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Maladie des taches noires de l'ananas : étude des relations hôte-pathogène et compréhension des mécanismes physiologiques de résistance
Abstract
La maladie de la tache noire affecte les fruits d’ananas mature, les rendant impropre à la consommation. Actuellement, aucune méthode de contrôle n'est disponible pour cette maladie. Une meilleure connaissance du pathosystème est nécessaire pour trouver des moyens de lutte efficaces.Des entretiens et échantillonnages menés auprès de producteurs durant l’hiver austral révèlent une prévalence de la maladie de 74%. Les champignons pathogènes appartiennent à plusieurs espèces : Fusarium ananatum (72% des isolats), Talaromyces stollii (21%), F. oxysporum (6%) et F. proliferatum (1%). Leur potentiel toxinogène a été déterminer, Les champignons du genre Fusarium ont produit des mycotoxines identifiées comme les fumonisines FB1, FB2 et la beauvericine. Sur un milieu de culture ananas, une concentration en beauvericine de 34959 µg kg-1 a été mesurée pour l’espèce F. proliferatum.Une méthode d’inoculation de Fusarium ananatum directement dans le parenchyme a permis de décrire la réponse du biochimique du fruit. La voie des phénylpropanoïdes est sollicitée, particulièrement avec l’élicitation du caffeoylisocitrate et du coumaroylisocitrate dans la zone infectée. Une comparaison des profils métaboliques montre que la réponse du fruit à une inoculation est plus importante chez le cultivar résistant ‘MD-2’ que chez le cultivar sensible ‘Queen’. La majorité des métabolites élicités par l’attaque sont déjà présents dans les fruits sains mature de la variété résistante. Le potentiel antifongique des composés phénoliques à était évalué. Les acides coumarique, caféoylquinique et férulique inhibent la croissance du mycélium à des concentrations similaires à celle trouvées dans les fruits infectés.Une approche par imagerie a permis de décrire l’anatomie des fruits des deux cultivars et notamment la fusion imparfaite des sépales et bractée chez ‘Queen’. Les nectaires et les parois carpellaires jouent un rôle clef dans le processus d'infection et de colonisation de Fusarium ananatum.
... On Reunion Island, F. ananatum, F. proliferatum, F. oxysporum, and T. stollii were identified in diseased pineapple tissues and characterized as prevalent species of the fruitassociated mycobiome. Their ability to promote black spot symptoms was confirmed and all four fungal species are considered as FCR pathogens [6,43]. Searching for microbial interactions and chemical communication as potential drivers of the FCR pathogenic mycobiome (pathobiome) structure, one isolated strain of each species previously validated for Koch's postulates was selected for co-culture bioassays [6,14]. ...
... Environmental conditions may significantly influence mycotoxigenic potentials of FCR pathogens especially in Reunion Island where production areas of the 'Queen Victoria' pineapple cultivar are characterized by an important diversity of microclimates [17]. Actually, pineapple presents important pH variations within the same infructescence due to the gradual maturation (from basal section to upper section) corresponding to the shell's color [43]. For a mature infructescence, the mean pH of pineapple cv. ...
Pineapple Fruitlet Core Rot (FCR) is a fungal disease characterized by a multi-pathogen pathosystem. Recently, Fusarium proliferatum, Fusarium oxysporum, and Talaromyces stollii joined the set of FCR pathogens until then exclusively attributed to Fusarium ananatum. The particularity of FCR relies on the presence of healthy and diseased fruitlets within the same infructescence. The mycobiomes associated with these two types of tissues suggested that disease occurrence might be triggered by or linked to an ecological chemical communication-promoting pathogen(s) development within the fungal community. Interactions between the four recently identified pathogens were deciphered by in vitro pairwise co-culture bioassays. Both fungal growth and mycotoxin production patterns were monitored for 10 days. Results evidenced that Talaromyces stollii was the main fungal antagonist of Fusarium species, reducing by 22% the growth of Fusarium proliferatum. A collapse of beauvericin content was observed when FCR pathogens were cross-challenged while fumonisin concentrations were increased by up to 7-fold. Antagonism between Fusarium species and Talaromyces stollii was supported by the diffusion of a red pigmentation and droplets of red exudate at the mycelium surface. This study revealed that secondary metabolites could shape the fungal pathogenic community of a pineapple fruitlet and contribute to virulence promoting FCR establishment.
... fr, www.france-bioimaging.org). This work was performed as part of a thesis conducted at the French Agricultural Research Centre for International Development (CIRAD) (Barral, 2017). ...
Fruitlet core rot is one of the major postharvest disease of pineapple (Ananas comosus var. comosus). In the past, control strategies were designed to eliminate symptoms without addressing their causes or mechanisms, thus achieving only moderate success. In this study, (i) we focused on the anatomy of the fruitlets in the resistant “MD-2” and susceptible “Queen” pineapple cultivars; (ii) we identified the key role of the carpel margin in the infection process; (iii) we identified the key role of the sinuous layer of thick-walled cells in the inhibition of Fusarium ananatum colonization; and (iv) we linked the anatomy of the fruitlets with the phenolic content of cell walls. The fruitlet anatomy of the two cultivars was studied using X-ray, fluorescence, and multiphoton microscopy. Sepals and bracts were not perfectly fused with each other, allowing the pathogen to penetrate the fruit even after flowering. In fact, the fungi were found in the blossom cups of both cultivars but only became pathogenic in the flesh of the “Queen” pineapple fruit under natural conditions. The outer layer of the “MD-2” cavity was continuous with thick cell walls composed of ferulic and coumaric acids. The cell walls of the “Queen” blossom cup were less lignified at the extremities, and the outer layer was interspersed with cracks. The carpel margins were fused broadly in the “MD-2” pineapple, in contrast to the “Queen” pineapple. This blemish allows the fungus to penetrate deeper into the susceptible cultivar. In pineapple fruitlets, the hyphae of F. ananatum mainly progressed directly between cell walls into the parenchyma but never reached the vascular region. A layer of thick-walled cells, in the case of the resistant cultivar, stopped the colonization, which were probably the infralocular septal nectaries. Anatomical and histochemical observations coupled with spectral analysis of the hypodermis suggested the role of lignin deposition in the resistance to F. ananatum. The major phenolics bound to the cell walls were coumaric and ferulic acids and were found in higher amounts in the resistant cultivar postinoculation. The combination of fruitlet anatomy and lignification plays a role in the mechanism of host resistance to fruitlet core rot.
We present the latest version of the Molecular Evolutionary Genetics Analysis (MEGA) software, which contains many sophisticated
methods and tools for phylogenomics and phylomedicine. In this major upgrade, MEGA has been optimized for use on 64-bit computing
systems for analyzing bigger datasets. Researchers can now explore and analyze tens of thousands of sequences in MEGA. The
new version also provides an advanced wizard for building timetrees and includes a new functionality to automatically predict
gene duplication events in gene family trees. The 64-bit MEGA is made available in two interfaces: graphical and command line.
The graphical user interface (GUI) is a native Microsoft Windows application that can also be used on Mac OSX. The command
line MEGA is available as native applications for Windows, Linux, and Mac OSX. They are intended for use in high-throughput
and scripted analysis. Both versions are available from www.megasoftware.net free of charge.
In search for renewable energy sources, genetic engineering is a promising strategy to improve plant cell wall composition for biofuel and bioproducts generation. Lignin is a major factor determining saccharification efficiency and is therefore a prime target. Here, lignin content and composition were modified in poplar (Populus tremula×P. alba) by specifically downregulating CINNAMYL ALCOHOL DEHYDROGENASE1 (CAD1) by a hairpin-RNA-mediated silencing approach. These transgenic lines showed no biomass penalty despite a 10% reduction in Klason lignin content and severe shifts in lignin composition. NMR spectroscopy and thioacidolysis revealed a strong increase in sinapaldehyde incorporation into lignin, whereas coniferaldehyde was not markedly increased. Accordingly, ultrahigh-performance liquid chromatography-mass spectrometry-based phenolic profiling revealed a more than 24,000-fold accumulation of a newly identified compound made from 8-8 coupling of two sinapaldehyde radicals. However, no additional cinnamaldehyde coupling products could be detected. Instead, the CAD1-deficient lines accumulated a range of hydroxycinnamate-derived metabolites of which the most prominent accumulation was observed for a compound that was identified by purification and NMR as syringyl lactic acid hexoside. Our data suggest that upon downregulation of CAD1, coniferaldehyde is converted into ferulic acid and derivatives, whereas sinapaldehyde is either oxidatively coupled into S'(8-8)S' and lignin, or converted to sinapic acid and derivatives. The most prominent sink of the increased flux to hydroxycinnamates is syringyl lactic acid hexoside. Furthermore, low-extent saccharification assays, under different pretreatment conditions, showed strongly increased glucose and xylose release, suggesting that downregulating CAD1 is a promising strategy for improving lignocellulosic biomass for the 'sugar platform' industry.
Background
Plants contain a myriad of metabolites which exhibit diverse biological activities. However, in-depth analyses of these natural products with current analytical platforms remains an undisputed challenge due to the multidimensional chemo-diversity of these molecules, amplified by both isomerization and conjugation. In this study, we looked at molecules such as hydroxyl-cinnamic acids (HCAs), which are known to exist as positional and geometrical isomers conjugated to different organic acids namely quinic- and isocitric acid. Objective
The study aimed at providing a more defined distinction between HCA conjugates from Amaranthus viridis and Moringa oleifera, using mass spectrometry (MS) approaches. Methods
Here, we used a UHPLC–MS/MS targeted approach to analyze isobaric HCA conjugates extracted from the aforementioned plants. ResultsMass spectrometry results showed similar precursor ions and fragmentation pattern; however, distinct differences were seen with ions at m/z 155 and m/z 111 which are associated with isocitric acid conjugates. Conclusion
Our results highlight subtle differences between these two classes of compounds based on the MS fingerprints, enabling confidence differentiation of the compounds. Thus, these findings provide a template reference for accurate and confident annotation of such compounds in other plants.
Fusarium dimerum, typically a soil fungus, was isolated from an adult male suffering from a corneal ulcer following an injury to the eye. This fungus has not been described to cause human infections in South Africa and has not been recorded from soil, plant or organic material in this country. The macro- and microscopic characteristics of the isolate were found to be indistinguishable from described strains. Its authenticity was confirmed by comparing it to other human isolates from the eye obtained in the USA, thus rendering this the first report of F. dimerum from an eye infection in a human in South Africa.
The introduction of the elite pineapple variety, MD-2, has caused a significant market shift in the pineapple industry. Better productivity, overall increased in fruit quality and taste, resilience to chilled storage and resistance to internal browning are among the key advantages of the MD-2 as compared with its previous predecessor, the Smooth Cayenne. Here, we present the genome sequence of the MD-2 pineapple (Ananas comosus (L.) Merr.) by using the hybrid sequencing technology from two highly reputable platforms, i.e. the PacBio long sequencing reads and the accurate Illumina short reads. Our draft genome achieved 99.6% genome coverage with 27,017 predicted protein-coding genes while 45.21% of the genome was identified as repetitive elements. Furthermore, differential expression of ripening RNASeq library of pineapple fruits revealed ethylene-related transcripts, believed to be involved in regulating the process of non-climacteric pineapple fruit ripening. The MD-2 pineapple draft genome serves as
Erwinia amylovora is the causative agent of fire blight, a bacterial disease existing as an unsolved problem in most countries where pome fruits like apple (Malus domestica) and pear (Pyrus communis) or ornamental plants of Rosaceae are grown. The primary site of colonization is the open flower. As for the establishment of the disease, the importance of various organs within the flowers is considerably different. The usual place for developing a large epiphytic population is the stigma. The actual infection will be attained by the external washing (rain, heavy dew) of bacteria from the stigma to the hypanthium. The bacteria penetrate through the openings of the nectary, so, the nectarthodes are the main entrance sites for them. Nectar is an excellent medium for growth of fire blight bacteria. Most often, however, the incidence of disease is significantly less than the percentage of colonized flowers. Little is known about the interrelationships of free moisture, nectar sugar concentration, ovary water potential, fine-structural characteristics of nectary versus the disease incidence and severity. The aim of this paper is to review the ecology and infection biology of Erwinia amylovora on floral surfaces and in floral tissues.
Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established in various countries to protect consumers from the harmful effects of these mycotoxins. Several factors are involved in Fusarium disease and mycotoxin occurrence and among them environmental factors and the agronomic practices have been shown to deeply affect mycotoxin contamination in the field. In the present review particular emphasis will be placed on how environmental conditions and stress factors for the crops can affect Fusarium infection and mycotoxin production, with the aim to provide useful knowledge to develop strategies to prevent mycotoxin accumulation in cereals.
Fusarium is one of the most economically important fungal genus, since it includes many pathogenic species which cause a wide range of plant diseases. Morphological or molecular biology identification of Fusarium species is a limiting step in the fast diagnosis and treatment of plant disease caused by these fungi. Mass spectrometry by matrix-assisted laser/desorption ionisation-time-of-flight (MALDI-TOF)-based fingerprinting approach was applied to the fungal growth monitoring and direct detection of strain Fusarium guttiforme E-480 inoculated in both pineapple cultivars Pérola and Imperial side shoots, that are susceptible and resistant, respectively, to this fungal strain. MALDI-TOF MS technique was capable to detect fungal molecular mass peaks in the susceptible pineapple stem side shoot tissue. It is assumed that these molecular masses are mainly constituted by ribosomal proteins. MALDI-TOF-based fingerprinting approach has herein been demonstrated to be sensitive and accurate for the direct detection of F. guttiforme E-480 molecular masses on both susceptible and resistant pineapple side stem free of any pre-treatment. According to the results obtained, the changing on molecular mass peaks of infected susceptible pineapple tissue together with the possibility of fungal molecular masses analysis into this pineapple tissue can be a good indication for an early diagnosis by MALDI-TOF MS of pineapple fusariosis.
Gibberella and Fusarium Ear Rot and Fusarium Head Blight are major diseases affecting European cereals. These diseases are mainly caused by fungi of the Fusarium genus, primarily Fusarium graminearum and Fusarium verticillioides. These Fusarium species pose a serious threat to food safety because of their ability to produce a wide range of mycotoxins, including type B trichothecenes and fumonisins. Many factors such as environmental, agronomic or genetic ones may contribute to high levels of accumulation of mycotoxins in the grain and there is an urgent need to implement efficient and sustainable management strategies to reduce mycotoxin contamination. Actually, fungicides are not fully efficient to control the mycotoxin risk. In addition, because of harmful effects on human health and environment, their use should be seriously restricted in the near future. To durably solve the problem of mycotoxin accumulation, the breeding of tolerant genotypes is one of the most promising strategies for cereals. A deeper understanding of the molecular mechanisms of plant resistance to both Fusarium and mycotoxin contamination will shed light on plant-pathogen interactions and provide relevant information for improving breeding programs. Resistance to Fusarium depends on the plant ability in preventing initial infection and containing the development of the toxigenic fungi while resistance to mycotoxin contamination is also related to the capacity of plant tissues in reducing mycotoxin accumulation. This capacity can result from two mechanisms: metabolic transformation of the toxin into less toxic compounds and inhibition of toxin biosynthesis. This last mechanism involves host metabolites able to interfere with mycotoxin biosynthesis. This review aims at gathering the latest scientific advances that support the contribution of grain antioxidant secondary metabolites to the mechanisms of plant resistance to Fusarium and mycotoxin accumulation.
Fruit and vegetable farming generally involves high levels of chemical inputs despite the fact that consumers are increasingly concerned about the sanitary and organoleptic aspects of fruit quality. Pineapple is largely subject to these issues since it is dominated by conventional monocropping with high levels of agrochemical inputs due to nitrogen (N) and potassium (K) fertilisation, weed management, crop protection and flowering induction. However, low-input pineapple cropping systems are both rare and little documented. Our study aimed at replacing all or part of the chemical fertilisers used with local organic fertilisers. It was conducted on the cultivar ‘Queen Victoria’, without pesticides or herbicides, in Reunion Island. We compared the impacts of three fertilisation treatments on pineapple growth and yield, fruit quality traits, symptoms of two major fungal diseases in fruit and production costs and labour times: (i) conventional: NPK fertiliser at recommended doses (265.5 kg ha
−1
N–10.53 kg ha
−1
P–445.71 kg ha
−1
K); (ii) integrated:
Mucuna pruriens
green manure (240.03 kg ha
−1
N, 18.62 kg ha
−1
P, 136.11 kg ha
−1
K) incorporated into the soil and a half-dose of NPK fertiliser and (iii) organic:
M. pruriens
green manure incorporated into the soil and foliar applications of sugarcane vinasse from a local distillery, rich in K (14.44 g L
−1
). Our results showed that NPK fertilisation could be replaced by organic fertilisers as well as by integrated fertilisation. ‘D’-leaf analysis showed that vinasse supplies a largely sufficient K level for growing pineapples. With organic fertilisation, pineapple growth was slower, 199 days after planting vs. 149 days for integrated or conventional fertilisations, and fruit yield was lower, 47.25 t ha
−1
vs. 52.51 and 61.24 t ha
−1
, probably because
M. pruriens
green manure provided an early increase in soil mineral N, whereas N requirements are much higher four months after planting. However, the fruit weight (709.94 ± 123.53 g) was still within the size range required for the export market (600–900 g). Interestingly, organic fertilisation significantly reduced Leathery Pocket disease and produced the best quality fruit with the highest total soluble solids contents (TSS) and the lowest titratable acidity (TTA). Fruit quality was also significantly improved with integrated fertilisation, with fruit weight similar to that of conventional fertilisation. To conclude, these findings have implications for the sustainability of pineapple production and could lead to low-input innovative cropping systems that reduce production costs and develop local organic inputs.
Pineapple is considered as one of the most wanted tropical fruits and it is widely taken for fresh consumption as well as their flesh and juice are used for preparation of different product in Agro-processing industries. For such industrial processes, it is important to know the information of characteristics changes of pineapple during day after storage. Four varieties of pineapple were collected from different areas of Bangladesh named Honey Queen (H.Q), Giant Kew (G.K), Asshini and Ghorasal. Some Physico-chemical properties (weight loss, moisture content, ash and edible portion, pH, TSS, titrable acidity (TA), total sugar, reducing sugar) biochemical properties (ascorbic acid) and sensorial attributes (color, odor, firmness, appearances, sweetness and overall acceptability) of pineapple juice were studied during day after storage. This study examined the Comparison of different varieties of pineapple fruit characteristics and sensory quality of the pineapple fruits during storage. It was shown that there was a significant changes between the storage periods in relation to different varieties of fruits. The firmness of pineapple fruits were in outside and inside to be 0.21 to 0.27 N/m2 and 0.06 to 0.10 N/m2, respectively. The pH values of different varieties were found to be in the range of 4.30 to 4.36. The highest and lowest sweetness index were estimated to be 36.30 and 22.15 for Honey Queen and Asshini respectively. The highest and lowest magnitude of sugar contents of four pineapple varieties were found to be in the range of 14.16 to 15.8 mg/100g.The average TSS values were found to be 15.12%, 12.33%, 13.14% and 12.95% for H.Q., G.K., Asshini and Ghorashal, respectively. The comparative study indicated the characteristics of different varieties of pineapple changes during after storage.Res. Agric., Livest. Fish.2(3): 395-410, December 2015
Root and stem rot (RSR) disease caused by Fusarium oxysporum f. sp. radicis-vanillae (Forv) is the most damaging disease of vanilla (Vanilla planifolia and V. × tahitensis, Orchidaceae). Breeding programs aimed at developing resistant vanilla varieties are hampered by the scarcity of sources of resistance to RSR and insufficient knowledge about the histopathology of Forv. In this work we have (i) identified new genetic resources resistant to RSR including V. planifolia inbreds and vanilla relatives, (ii) thoroughly described the colonization pattern of Forv into selected vanilla accessions, confirming its necrotic non-vascular behavior in roots, and (iii) evidenced the key role played by hypodermis, and particularly lignin deposition onto hypodermal cell walls, for resistance to Forv in two highly resistant vanilla accessions. Two hundred and fifty-four vanilla accessions were evaluated in the field under natural conditions of infection and in controlled conditions using in vitro plants root-dip inoculated by the highly pathogenic isolate Fo072. For the 26 accessions evaluated in both conditions, a high correlation was observed between field evaluation and in vitro assay. The root infection process and plant response of one susceptible and two resistant accessions challenged with Fo072 were studied using wide field and multiphoton microscopy. In susceptible V. planifolia, hyphae penetrated directly into the rhizodermis in the hairy root region then invaded the cortex through the passage cells where it induced plasmolysis, but never reached the vascular region. In the case of the resistant accessions, the penetration was stopped at the hypodermal layer. Anatomical and histochemical observations coupled with spectral analysis of the hypodermis suggested the role of lignin deposition in the resistance to Forv. The thickness of lignin constitutively deposited onto outer cell walls of hypodermis was highly correlated with the level of resistance for 21 accessions tested. The accumulation of p-coumaric and sinapic acids, two phenolic precursors of lignin, was observed in the resistant plants inoculated with Fo072, but not in the susceptible one. Altogether, our analyses enlightened the mechanisms at work in RSR resistant genotypes and should enhance the development of novel breeding strategies aimed at improving the genetic control of RSR of vanilla.
Pineapple (Ananas comosus (L.) Merr.) is the most economically valuable crop possessing crassulacean acid metabolism (CAM), a photosynthetic carbon assimilation pathway with high water-use efficiency, and the second most important tropical fruit. We sequenced the genomes of pineapple varieties F153 and MD2 and a wild pineapple relative, Ananas bracteatus accession CB5. The pineapple genome has one fewer ancient whole-genome duplication event than sequenced grass genomes and a conserved karyotype with seven chromosomes from before the ρ duplication event. The pineapple lineage has transitioned from C3 photosynthesis to CAM, with CAM-related genes exhibiting a diel expression pattern in photosynthetic tissues. CAM pathway genes were enriched with cis-regulatory elements associated with the regulation of circadian clock genes, providing the first cis-regulatory link between CAM and circadian clock regulation. Pineapple CAM photosynthesis evolved by the reconfiguration of pathways in C3 plants, through the regulatory neofunctionalization of preexisting genes and not through the acquisition of neofunctionalized genes via whole-genome or tandem gene duplication.
Fusarium graminearum is the causal agent of Fusarium head blight (FHB) and Gibberella ear rot (GER), two devastating diseases of wheat, barley, and maize. Furthermore, F. graminearum species can produce type B trichothecene mycotoxins that accumulate in grains. Use of FHB and GER resistant cultivars is one of the most promising strategies to reduce damage induced by F. graminearum. Combined with genetic approaches, metabolomic ones can provide powerful opportunities for plant breeding through the identification of resistant biomarker metabolites which have the advantage of integrating the genetic background and the influence of the environment. In the past decade, several metabolomics attempts have been made to decipher the chemical defense that cereals employ to counteract F. graminearum. By covering the major classes of metabolites that have been highlighted and addressing their potential role, this review demonstrates the complex and integrated network of events that cereals can orchestrate to resist to F. graminearum.
This book, intended for researchers, professional horticulturists and tropical fruit growers, covers the history, distribution and world production; botany; breeding, genetic engineering, selection and cultivars; crop environment viz., temperature, water and light; propagation, cultural systems; flowering and fruit development; pests, diseases and weeds; postharvest physiology, handling and storage and processing of pineapple.
A simple method is described for designing primer sets that can amplify specific protein-encoding sequences in a wide variety of filamentous ascomycetes. Using this technique, we successfully designed primers that amplified the intergenic spacer region of the nuclear ribosomal DNA repeat, portions of the translation elongation factor 1 alpha, calmodulin, and chitin synthase 1 genes, and two other genes encoding actin and ras protein. All amplicons were sequenced and determined to amplify the target gene. Regions were successfully amplified in Sclerotinia sclerotiorum and other sclerotiniaceous species, Neurospora crassa, Trichophyton rubrum, Aspergillus nidulans, Podospora anserina, Fusarium solani, and Ophiostoma novo-ulmi. These regions are a potentially rich source of characters for population and speciation studies in filamentous ascomycetes. Each primer set amplified a DNA product of predicted size from N. crassa.
A morphological study of the ascocarps of 29 strains of Aspergillus and Penicillium indicates that these forms comprise five genera of the Eurotiaceae. The perfect stages of Aspergillus are included in the genera Eurotium, Sartorya, and Emericella. Those of Penicillium are included in Carpenteles and Talaromyces, the latter a new genus erected for the forms with ascocarpic walls of interwoven hyphae. Species which had not previously been assigned to an ascomycetous genus are here so assigned.
This fascinating work provides state-of-the-art information on phenolic compounds in fruits. Written in a concise format, it covers qualitative aspects by demonstrating the diversity of phenolic features in the major fruits of economic importance. It extensively covers the role played by phenolic compounds in the quality of fruits, with regard to organoleptic characteristics and also as a parameter involved in enzymatic browning and other modifications which take place during fruit processing. This easy-to-read resource particularly emphasizes beverages made from fruits and the use of phenolic compounds in the detection of adulteration. This reference is indispensable to researchers in fundamental fields (plant physiologists, phytochemists, biochemists) as well as engineers and technologists working on practical applications in fruits.
Phylogenetic relationships of the phyto-pathogenic Gibberella fujikuroi species complex were investigated by maximum parsimony analysis of DNA sequences from multiple loci. Gene trees inferred from the β-tubulin gene exons and introns, mitochondrial small subunit (mtSSU) rDNA, and 5′ portion of the nuclear 28S rDNA were largely concordant, and in a combined analysis, provide strong statistical support for a phylogeny consistent with species radiations in South America, Africa, and Asia. These analyses place the American clade as a mono-phyletic sister-group of an African-Asian clade. Africa is the most phylogenetically diverse area examined with 16 species, followed by America (12 species) and Asia (8 species). The biogeographic hypothesis proposed from the phylogenetic evidence is based primarily on the formation of natural barriers associated with the fragmentation of the ancient super-continent Gondwana. Discordance of the nuclear ribosomal internal transcribed spacer (ITS) based tree with gene trees from the other loci sequenced is due to nonorthologous ITS2 sequences. The molecular evidence suggests the divergent ITS2 types were combined by an ancient interspecific hybridization (xenologous origin) or gene duplication (paralogous origin) that predates the evolutionary radiation of the G. fujikuroi complex. Two highly divergent nonorthologous ITS2 types designated type I and type II were identified and characterized with conserved ITS and ITS2 type-specific polymerase chain reaction (PCR) primers and DNA sequence analysis. Only the major ITS2 type is discernible when conserved ITS primers are used; however, a minor ITS2 type was amplified from every strain tested with type-specific PCR primers. The evolutionary pattern exhibited by the major ITS2 type is homoplastic when mapped onto the species lineages inferred from the combined nuclear 28S rDNA, mtSSU rDNA, and β-tubulin gene sequences. Remarkably, the data indicate the major ITS2 type has switched between a type I and type II sequence at least three times during the evolution of the G. fujikuroi complex, but neither type has been fixed in any of the 45 species examined. Twenty-six of the 45 species included in this study represent either new species (23 species), new combinations (F. bulbicola and F. phyllophilum), or a rediscovered species (F. lactis). The results further indicate that traditional sectional and species-level taxonomic schemes for this lineage are artificial and a more natural classification is proposed.
Ten Fusarium species within the Gibberella fujikuroi complex are described and illustrated as new species: F. acutatum ex Triticum sp. (wheat) and Cajanus sp.,F. begoniae ex Begonia elatior hybrid, F. circinatum ex Pinus spp. and its teleomorph G. circinata, F. concentricum ex Musa sapientum (banana) and Nilaparvata lugens (Asian brown leaf hopper), F. denticulatum ex Ipomoea batatas (sweet potato), F. guttiforme ex Ananas comosus (pineapple), F. phyllophilum ex Dracaena, Sansevieria and Gasteria spp., F. pseudocircinatum ex Solanum sp. as well as Pinus kesiya and Heteropsylla incisa, F. pseudonygamai ex Pennisetum typhoides (millet) and F. ramigenum ex Ficus carica (figs). One variety, F. sacchari var. elongatum ex Nerine bowdenii, Vallota sp. and Haemanthus sp. is given species rank as F. bulbicola. A neotype is designated for F. lactis, a pathogen of Ficus carica. A key to the described species is provided.
Fusarium ananatum causes fruitlet core rot (FCR) in pineapple (Ananas comosus var. comosus) when the fruit reaches maturity. Hidden symptoms make it difficult to assess the disease, regardless of its stage, and basic questions concerning the involvement of the phenolic compounds in response to infection remain unknown. A direct inoculation method of F. ananatum in pineapple fruitlets was developed to monitor the growth of black spots and the changes in phenolic acids and ascorbic acid concentration under controlled conditions. After inoculation, infection began with a flesh discolouration at the inoculation point and then spread in a darker shade to form a black spot. Coumaroyl-isocitric and caffeoyl-isocitric acids levels respectively showed a 150- and 200-fold increase in infected fruitlet when compared to healthy fruitlet. These hydroxycinnamic acids increased minimally in the adjacent fruitlet and remained stable in the other parts of the fruit. By contrast, sinapic acid and hydroxybenzoic acid isomers (HBA) decreased after F. ananatum inoculation in the infected fruitlet, whereas they remained stable in the adjacent and healthy fruitlets. Ascorbic acid decreased to zero in the infected fruitlet. The antifungal activity of phenolic compounds and ascorbic acid was evaluated against the mycelial growth of F. ananatum. p-Coumaric acid exhibited a total inhibition of the mycelial growth at 1000 μg g⁻¹. Ferulic acid inhibited 64 % of mycelial growth at a concentration of 1000 μg g⁻¹. Caffeoylquinic acid, sinapic acid, and ascorbic acid also showed significant antifungal activity, but to a lesser extent. Finally, coinoculation of the hydroxycinnamic acids with the pathogen restrains its development in the fruit. This is the first study to highlight the involvement of phenolic compounds in the pineapple FCR disease.
Background:
Pineapple is the fruit of Ananas comosus var. comosus plant, being cultivated in tropical areas and has high energy content and nutritional value. Herein, 30 samples of pineapple cv. Vitória were analyzed as a function of the maturation stage (0-5) and their physicochemical parameters monitored. Besides, negative-ion mode electrospray ionization mass spectrometry (ESI(-)FT-ICR MS) was used to identify and semi-quantify primary and secondary metabolites present in the crude and phenolic extracts of pineapple, respectively.
Results:
Physicochemical tests show an increase in the total soluble solids (TSS) values and in the TSS/total titratable acidity ratio as a function of the maturity stage, where a maximum value was observed in stage 3 (¾ of the fruit is yellow, which corresponds to the color of the fruit peel). ESI(-)FT-ICR MS analysis for crude extracts showed the presence mainly of sugars as primary metabolites present in deprotonated molecule form ([M-H](-) and [2M-H](-) ions) whereas, for phenolic fractions, 13 compounds were detected, being the most abundant in the third stage of maturation. This behavior was confirmed by quantitative analysis of total polyphenols.
Conclusion:
ESI-FT-ICR MS was efficient in identifying primary (carbohydrates and organic acids) and secondary metabolites (13 phenolic compounds) presents in the crude and phenolic extract of the samples, respectively.
Fusarium verticillioides causes ear rot in maize and contaminates the kernels with the fumonisin mycotoxins. It is known that plant lipoxygenase (LOX)-derived oxylipins regulate defence against pathogens and that the host-pathogen lipid cross-talk influences the pathogenesis. The expression profiles of fifteen genes of the LOX pathway were studied in kernels of resistant and susceptible maize lines, grown in field condition, at 3, 7 and 14 days post inoculation (dpi) with F. verticillioides. Plant defence responses were correlated with the pathogen growth, the expression profiles of fungal FUM genes for fumonisin biosynthesis and fumonisin content in the kernels. The resistant genotype limited fungal growth and fumonisin accumulation between 7 and 14 dpi. Pathogen growth became exponential in the susceptible line after 7 dpi, in correspondence with massive transcription of FUM genes and fumonisins augmented exponentially at 14 dpi. LOX pathway genes resulted strongly induced after pathogen inoculation in the resistant line at 3 and 7 dpi, whilst in the susceptible line the induction was reduced or delayed at 14 dpi. In addition, all genes resulted overexpressed before infection in kernels of the resistant genotype already at 3 dpi. The results suggest that resistance in maize may depend on an earlier activation of LOX genes and genes for jasmonic acid biosynthesis.
Pineapple occupies an important phylogenetic position and its reference genome expedites genomic research within the family Bromeliaceae and more widely among monocots. One such research focus is the evolution of crassulacean acid metabolism (CAM) photosynthesis. Acquiring circadian clock cis-regulatory elements in CAM-related genes might be a critical step in the evolution of this form of photosynthesis. Follow-up studies will clarify the processes and evolutionary forces leading to the multiple independent origins of CAM photosynthesis within the family Bromeliaceae and in over 400 genera across 36 families.
A typical symptom of postharvest chilling injury (PCI) in pineapple fruit (Ananas comosus L.) is internal browning (IB) near the fruit core. Since vascular bundles (VBs) are localized to this region, it was hypothesized that the VBs might be the site of IB. To test this, the anatomy and histochemistry of VBs during chilling stress in four pineapple cultivars with different levels of sensitivity to PCI were examined. Fruit were stored at 10 °C for up to three weeks to stimulate translucency symptoms (TS; the initiation of IB). After three weeks of chilling exposure, the cultivars ‘MD2′ showed 0%, ‘Pattavia’ and ‘Savee’ showed 10-16%, and ‘Trad Sri Thong’ showed 100% TS and IB symptom. Scanning electron microscopy and in situ histochemical staining techniques that detect enzymes and substrates commonly associated with IB initiation were used in parallel. The TS of pineapple fruit coincided with the collapse of the phloem tissue. The VBs in the tissue where IB was initiated (i.e. the flesh adjacent to the core or F/C) had the highest activity of polyphenol oxidase, hydrogen peroxide, and phenolic compounds. The IB-resistant ‘MD2′ genotype had fewer VBs, but a greater proportion of sclerenchyma fibers (P < 0.05) than did the susceptible ‘Trad Sri Thong’. Based on these data, the first report of pineapple IB occurrence in the phloem was proposed.
Polyphenol oxidase (PPO) activity was found to be low in the leaves, roots, inflorescence tissues and developing and mature fruit of pineapple (Ananas comosus L.). In fruit affected by the chill-induced internal browning disorder known as Blackheart, PPO activity was 10-fold higher than in unaffected fruit, and there was a direct correlation between PPO activity and the severity of Blackheart symptoms. Degenerate oligonucleotide primers were designed to conserved regions of plant PPO genes, and used to amplify two distinct pineapple PPO cDNAs, designated PINPPO1 (2181 bp) and PINPPO2 (1319 bp), which share 81% sequence identity at the DNA level and show a high degree of homology to other plant PPO genes. PINPPO1 encodes a peptide of 604 amino acids, including a putative transit peptide of 95 amino acids and two copper-binding regions, CuA and CuB, which are highly conserved in plant PPOs. Southern analysis suggested the presence of at least four PPO genes in pineapple. Expression of PINPPO1 and PINPPO2 was low in roots, leaves, inflorescence tissues and developing fruit, but was strongly up-regulated in response to chilling and wounding. These results indicate that PPO is synthesised de novo in response to chilling of pineapple fruit, and implicate a role for the enzyme in the development of Blackheart disorder.
Fusarium Head Blight and Gibberella Ear Rot, mainly caused by the fungi Fusarium graminearum and Fusarium culmorum, are two of the most devastating diseases of small-grain cereals and maize. In addition to yield loss, these diseases frequently result in contamination of kernels with toxic type B trichothecenes. The potential involvement of chlorogenic acid in cereal resistance to Fusarium Head Blight and Gibberella Ear Rot and to trichothecene accumulation was the focus of this study. The effects of chlorogenic acid and one of its hydrolyzed products, caffeic acid, on fungal growth and type B trichothecenes biosynthesis were studied using concentrations close to physiological amounts quantified in kernels and a set of F. graminearum and F. culmorum strains. Both chlorogenic and caffeic acids negatively impact fungal growth and mycotoxin production, with caffeic acid being significantly more toxic. Inhibitory efficiencies of both phenolic acids were strain-dependent. To further investigate the antifungal and anti “mycotoxin” effect of chlorogenic and caffeic acids, the metabolic fate of these two phenolic acids was characterized in supplemented F. graminearum broths. For the first time, our results demonstrated the ability of F. graminearum to degrade chlorogenic acid into caffeic, hydroxychlorogenic and protocatechuic acids and caffeic acid into protocatechuic and hydroxycaffeic acids. Some of these metabolic products can contribute to the inhibitory efficiency of chlorogenic acid that, therefore, can be compared as a “pro-drug”. As a whole, our data corroborate the contribution of chlorogenic acid to the chemical defense that cereals employ to counteract F. graminearum and its production of mycotoxins.
The date pineapple (Ananas comosus var. comosus) was introduced to Hawaii is not known, but its presence was first recorded in 1813. When American missionaries first arrived in Hawaii in 1820, pineapple was found growing wild and in gardens and small plots. The pineapple canning industry began in Baltimore in the mid-1860s and used fruit imported from the Caribbean. The export-based Hawaii pineapple industry was developed by an entrepreneurial group of California migrants who arrived in Hawaii in 1898 and the well-connected James D. Dole who arrived in 1899. The first profitable lot of canned pineapples was produced by Dole's Hawaiian Pineapple Company in 1903 and the industry grew rapidly from there. Difficulties encountered in production and processing as the industry grew included low yields resulting from severe iron chlorosis and the use of low plant populations, mealybug wilt that devastated whole fields, inadequate machinery that limited cannery capacity, and lack of or poorly developed markets for the industry's canned fruit. The major production problems were solved by public- and industry-funded research and innovation in the field and in the cannery. An industry association and industry-funded cooperative marketing efforts, initially led by James Dole, helped to expand the market for canned pineapple. Industry innovations were many and included: selection of 'Smooth Cayenne' pineapple as the most productive cultivar with the best quality fruit for canning; identification of the cause of manganese-induced iron chlorosis and its control with biweekly iron sulphate sprays; the use of mulch paper and the mechanization of its application, which increased yields by more than 20 t·ha-1; and the invention of the Ginaca peeler-corer machine, which greatly sped cannery throughput. Nematodes were also a serious problem for the industry, which resulted in the discovery and development of nematicides in the 1930s. As a result, by 1930 Hawaii led the world in the production of canned pineapple and had the world's largest canneries. Production and sale of canned pineapple fell sharply during the world depression that began in 1929. However, the formation of an industry cartel to control output and marketing of canned pineapple, aggressive industry-funded marketing programs, and rapid growth in the volume of canned juice after 1933 restored industry profitability. Although the industry supported the world's largest pineapple breeding program from 1914 until 1986, no cultivars emerged that replaced 'Smooth Cayenne' for canning. The lack of success was attributed in part to the superiority of 'Smooth Cayenne' in the field and the cannery, but also to the difficulty in producing defect-free progeny from crosses between highly heterozygous parents that were self-incompatible. Production of canned pineapple peaked in 1957, but the stage was set for the decline of the Hawaii industry when Del Monte, one of Hawaii's largest canners, established the Philippine Packing Corporation (PPC) in the Philippines in the 1930s. The expansion of the PPC after World War II, followed by the establishment of plantations and canneries by Castle and Cooke's Dole division in the Philippines in 1964 and in Thailand in 1972, sped the decline. The decline occurred mainly because foreign-based canneries had labor costs approximately one-tenth those in Hawaii. As the Hawaii canneries closed, the industry gradually shifted to the production of fresh pineapples. During that transition, the pineapple breeding program of the Pineapple Research Institute of Hawaii produced the MD-2 pineapple cultivar, now the world's pre-eminent fresh fruit cultivar. However, the first and major beneficiary of that cultivar was Costa Rica where Del Monte had established a fresh fruit plantation in the late 1970s. Dole Food Co. and Maui Gold Pineapple Co. continue to produce fresh pineapples in Hawaii, mostly for the local market. All of the canneries eventually closed, the last one on Maui in 2007.
Dans le cadre d'un projet de cooperation, le CIRAD-FLHOR et l'EMBRAPA ont collecte le germoplasme des genres Ananas et Pseudananas dans des zones de diversite majeure : le Bassin Amazonien (Amapa, Rio Negro, Rio Solimoes, Acre et Nord du Mato Grosso), la Guyane Francaise et le Sud du Bresil. Les expeditions ont ete organisees sur la base des donnees d'herbiers et d'informations recues des scientifiques et des agents regionaux de developpement, completees par enquete aupres des populations locales. Des moyens de transports routiers, fluviaux et plus rarement aeriens ont ete utilises. 434 accessions, en majorite sauvages ou cultivars natifs, ont ete collectees. Certaines sont vraisemblablement des doublons, les observations morphologiques ayant eu lieu a des stades de developpement ou dans des conditions ecologiques differentes. Les differentes especes presentent une repartition geographique coherente, mais de nombreux clones sont inclassables selon la cle de determination usuelle, dont la validite s'avere contestable. La structure de certaines populations observees a l'etat sauvage met en evidence le role actif de la reproduction sexuee dans la multiplication et la diversification. La variabilite tres grande de l'espece cultivee, Ananas comosus, n'a pu etre analysee en utilisant la repartition classique en 5 groupes. Le materiel vegetal est conserve dans les collection du CIRAD-FLHOR en Martinique, et de l'EMBRAPA-CNPMF a Cruz das Almas. Sa caracterisation botanique, agromorphologique et moleculaire est en cours. (Resume d'auteur)
Fruitlet Core Rot is one on the main disease that affects pineapple fruit development in the world. However, factors promoting the disease are not well known. A large survey, including soil, climatic, physiological and pathological variables at a field scale, and including spatial heterogeneity and temporal variability, was designed and conducted in the pineapple production area in Martinique. This on farm-approach allowed the identification and specification of the main factors responsible for the disease. Fruit sampling analysis revealed the Penicillium funiculosum was involved in 95% of the observer cases. However, although P. funiculosum was widespread in the soils of the survey, no quantitative relation was established between the quantity of inoculum in the soil or on the plant and the development of P. funiculosum in fruits. Fruit observations at harvest time showed a high level of variation between fruits within a field. However, significant correlations between the percentage of infected fruits within a field, the average number of spots per fruit and their size were established. A global analysis of the data showed that average ascorbic acid content in fruits at harvest is negatively linked with the percentage of infected fruits. The nutritional status of the plants, especially low levels of calcium and magnesium, and/or high levels of nitrogen, is also a significant promoting factor for the development of the disease. It is concluded that Fruitlet Core Rot in Martinique is promoted by a combination of factors which determine the sensitivity of fruits. Climatic conditions before harvest, acid content, and nutritional status are the main factors.
We have reported on the unexplained increase in black spot which was observed where Thioflo (endosulfan) was applied for mite control on Queen pineapples in Hluhluwe. The previous trials were not all replicated, two being observational trials, but sufficient concern was raised for growers to cease using Thioflo. The current series of trials was initiated to establish whether Thioflo applications increased black spot incidence in pineapple. The trial was designed as a randomised block with seven treatments and four replicates, repeated on three farms. A five spray Thioflo program effectively controlled mites but was consistently and significantly in the worst group as regards black spot control at all sites. This contradicts previous results obtained with varying endosulfan sprays from the Eastern Cape and elsewhere, including Hluhluwe.
A process-based model simulating the change in total soluble solids (TSS (%)) in fruit flesh was developed to describe the effect of climatic conditions on the sugar content of ‘Queen Victoria’ pineapple at harvest on Reunion Island. Sugar content varies throughout fruit development according to three processes (the supply of carbohydrates to the fruit, fruit metabolism, and dilution) which are affected by environmental factors, mainly temperature, rainfall and fertilization. The ecophysiological model of soluble sugar accumulation was linked to SIMPIÑA, a crop model that accurately predicts the daily increases in flesh dry and fresh weight. When the process-based model and crop model were linked, the dry and fresh matter of the pineapple flesh, as affected by climatic conditions, could be used as inputs to predict the TSS (%) at harvest. The relative rate of transformation of carbon as sugars in the fruit flesh for the synthesis of compounds other than sugars was estimated during fruit growth. TSS (%) were compared for harvested fruit grown under eight agro-climatic conditions. In the flesh of fruit harvested close to maturity, i.e., at 1400 degree-days after flowering, TSS (%) were significantly related (r2 = 0.55, P < 0.001) to total soluble sugar content. The variability of TSS (%) between the eight agro-climatic groups ranged from 16.9 for pineapples grown in dry locations irrigated, under N-deficit conditions to 19.4 for pineapples grown in dry locations, without irrigation and without N deficiency. The variability of TSS (%) was substantial within each of the eight agro-climatic groups: standard deviations ranged from 0.9 to 1.5 for pineapples grown in dry locations, irrigated, without N deficiency and in dry locations, without irrigation and without N deficiency, respectively. For data from 14 experiments conducted under different climatic conditions, N fertilization, and irrigation conditions, the model predicted the TSS (%) at harvest with an RRMSE of 0.04. By linking this sugar model to the SIMPIÑA crop model, the impact of environmental conditions and cultural practices on the growth and development of pineapple are taken into account to predict the gustatory quality of pineapple grown on Reunion Island. The model could have a practical application to manage fruit quality, plan harvest, and marketing.
Penicilium funiculosum has been shown to be the main causal organism of the pineapple fruit diseases called fruitlet core rot (FCR) and leathery pocket (LP). These diseases occur in several producing countries and may result in important losses concerning fresh as well as processed fruits. Both FCR and LP result of preflower infection by P.funiculosum, but two distinct processes lead to either FCR or LP. Several factors seem to be implicated in the pathogenesis of P.funiculosum making these two fruit diseases very intricate. Some research allowed to display some aspects about the etiology of FCR / LP : 1. Importance of the inflorescence developmental stages (before anthesis) in relation to contamination. - 2. Implication of mites (Steneotarsonemus ananas). - 3. Importance of some environmental conditions. - 4. Physio-biochemical characteristics of the fruit during maturation.
Sugar accumulation of 'Comte de Paris' pineapple fruits was measured from 20 days after anthesis (DAA) to maturity at 80 DAA. The sugar content was highest in the basal section of ripe fruit, followed by the medial section, apical section and fruit core. Changes in activity of acid and neutral invertases (AI and NI respectively) and sucrose phosphate synthase (SPS) corresponded to changes in sugar concentration gradients within various sections during fruit maturation. The higher activity of invertase in the basal section of the fruit likely was associated with rapid cleavage of sucrose. High invertase activity would also help to form a sucrose gradient between the leaves and the fruit, which facilitated sucrose transport to the fruit. Higher SPS activity in the apical section could promote the synthesis of sucrose, which indicated that the difference between activity of invertase and SPS resulted in the difference of sugar accumulation among the various sections. Our results indicated that the SPS and invertase activity was a gradient distribution among the sections at the mature stage, which was similar with the sugar concentration, which showed the activities of SS and SPS had a great impact on the sugar accumulation in the medial and the basal sections of fruit during the period of 70 days after anthesis (DAA). Rapid sucrose accumulation of different sections was related with the increase of SPS activity and the reduction of NI activity from 70 to 80 d. The activity of SS regulated the sucrose accumulation in the fruit apical and core section in the period of 70 DAA, However, the activities of AI, NI and SPS regulated the sucrose accumulation of the fruit core after 70 DAA, whereas the activities of NI and SPS regulated the sucrose accumulation in the apical, medial and basal sections of the fruit.