Joao Paulo Rodrigues Marques

University of São Paulo | USP · Department of Basic Sciences (ZAB)

Citrus postbloom fruit drop, caused by Colletotrichum spp., is an important disease in the Americas. The pathogen infects citrus flowers, produces orange-brown lesions on petals, and may cause the abscission of young fruit. In diseased flowers, the calyxes remain attached to the peduncle after the young fruit drop. No anatomical and microanalysis s...

The increasing number of patents suggests that the use of nanoparticles (NP) in agriculture will continue to grow in the future. Properties associated with nanosized objects might be desirable, but may pose a threat to the environment since the fate of nanomaterials is poorly understood. Seed treatment is an extensive practice to provide micronutri...

Laboratory microprobe X-ray fluorescence (μ-XRF) spectrometry is a powerful analytical technique able to detect trace elements in biological samples. The present study compared univariate and multivariate strategies to investigate the elements detected with μ-XRF during soybean (Glycine max (L.) Merrill) germination. The conventional approach, i.e....

Strains of Bacillus thuringiensis (Bt) are commonly commercialized as bioinoculants for insect pest control, but their benefits go beyond their insecticidal property: they can act as plant growth-promoters. Auxins play a major role in the plant growth promotion. However, the mechanism of auxin production by the Bacilli group, and more specifically...

o longo desta obra são descritas diferentes técnicas em campo claro, fluorescência e microscopia eletrônica destacando a importância da escolha dos procedimentos de acordo com a necessidade e recursos disponíveis ao pesquisador. Acrescenta-se que esse Manual de Técnicas não visa investigar o funcionamento dos diferentes tipos de microscópios, mas s...

Breath passion fruit (Passifloranitida) has been used as rootstock for sour passion fruit (P. edulis) in order to control wilting and collar rot caused by Fusarium spp. However, it is supposedly susceptible to root-knot nematode (Meloidogyne incognita), which is widespread in tropical crop fields. Two trials were carried out to assess the effect of...

Breath passion fruit (Passiflora nitida) has been used as rootstock for sour passion fruit (P. edulis) in order to control wilting and collar rot caused by Fusarium spp. However, it is supposedly susceptible to root-knot nematode (Meloidogyne incognita), which is widespread in tropical crop fields. Two trials were carried out to assess the effect o...

Fertilization with boron (B) is a crucial aspect in the management of tropical soils to achieve high yield and wood quality in forest species. However, studies are still needed for a better understanding of the effects of B on the anatomy and physiology of African mahogany to improve borate fertilization programs in terms of doses and sources of B....

A qualidade do café é influenciada pelas condições climáticas do local de cultivo e principalmente do método de processamento dos grãos, conferindo características distintas ao produto. Objetivou-se avaliar a relação entre o processamento de pós-colheita e os atributos químicos e sensoriais de cafés de três locais de Minas Gerais. Nas avaliações fo...

Elephant grass (Pennisetum purpureum) exhibits high biomass production, is readily accepted by animals, and demonstrates good adaptation to the various soil types. Consequently, the utilization of P. purpureum shows promise in amending surface and subsurface soil acidity, thereby contributing to increased crop yield while enhancing water and nutrie...

The citrus leprosis is responsible for causing major damage in fruit production. The disease, in the stems, is characterized by caused “scaly bark” lesions of reddish tone, depending on the stage they can be called blisters and make ruptures in the longitudinal direction. The aim of this study was to analyze the evolution of leprosis lesions of typ...

The sugarcane ( Saccharum spp.) genome is one of the most complex of all. Modern varieties are highly polyploid and aneuploid as a result of hybridization between Saccharum officinarum and S. spontaneum . Little research has been done on meiotic control in polyploid species, with the exception of the wheat Ph1 locus harboring the ZIP4 gene ( TaZIP4...

Bacillus thuringiensis (Bt) can be effective in controlling insect pests either in spray products or by their toxins expressed in transgenic crops. The discovery of Bt as endophytic in citrus opened new perspectives for the control of Diaphorina citri Kuwayama, the vector of the bacteria Candidatus Liberibacter spp. associated with Huanglongbing. I...

A obra traz em detalhes e com exemplos práticos - os processos de captação, edição e tratamento de imagens científicas, além dos padrões de exigência dos principais periódicos internacionais. Os autores apresentam ainda modos adequados para a captura de imagens em microscópio de luz e eletrônico, abordam como introduzir os conceitos sobre a captura...

Austropuccinia psidii is a biotrophic fungus that causes myrtle rust. First described in Brazil, it has since spread to become a globally important pathogen that infects more than 480 myrtaceous species. One of the most important commercial crops affected by A. psidii is eucalypt, a widely grown forestry tree. The A. psidii–Eucalyptus spp. interact...

ABSTRACT: This study explored a field-based approach to precisely characterize the dynamics of the storage proteins (albumins and globulins fractions) biosynthesis and mineral nutrient accumulation (phosphorus, potassium, calcium, magnesium, sulfur, iron, boron, manganese, zinc, and copper) profile throughout the development of soybean seeds. Stora...

Even though the electromagnetic counterpart AT2017gfo to the binary neutron star merger GW170817 is powered by the radioactive decay of r-process nuclei, only few tentative identifications of light r-process elements have been made so far. One of the major limitations for the identification of heavy nuclei is incomplete or missing atomic data. Whil...

The deficiency of calcium (Ca) reduces the quality and shelf life of fruits. In this scenario, although foliar spraying of Ca2+ has been used, altogether with soil fertilization, as an alternative to prevent deficiencies, little is known regarding its absorption dynamics by plant leaves. Herein, in vivo microprobe X-ray fluorescence was employed ai...

X-ray fluorescence spectroscopy (XRF) is a powerful technique for the in vivo assessment of plant tissues. However, the potential X-ray exposure damages might affect the structure and elemental composition of living plant tissues leading to artefacts in the recorded data. Herein, we exposed in vivo soybean (Glycine max (L.) Merrill) leaves to sever...

This study explored a field-based approach to precisely characterise the dynamics of the storage proteins (albumins and globulins fractions) biosynthesis and mineral nutrients accumulation (phosphorus, potassium, calcium, magnesium, sulphur, iron, boron, manganese, zinc, and copper) profile throughout the development of soybean seeds. It reveals th...

In 2017, the electromagnetic counterpart AT2017gfo to the binary neutron star merger GW170817 was observed by all major telescopes on Earth. While it was immediately clear that the transient following the merger event, is powered by the radioactive decay of r-process nuclei, only a few tentative identifications of light r-process elements have been...

Currently, there are no resistant sweet orange cultivars to the citrus canker (cc) [Xanthomonas citri subsp. citri (Xcc)], and the production of transgenic plants resistant to cc can be an efficient solution in the search of improved cultivars. Several strategies can be applied in this scenario, including the expression of genes that code for antim...

Presents a wide compilation of laboratory practices and of light and electron microscopy for plant pathology analysis This book focuses on the main pathogens ocurring in plants such as fungi, viruses or bacteria It serves as an easy-to-reference material for professors, undergraduate and graduate students

The present study explored the microprobe X-ray fluorescence spectroscopy (µ-XRF) for quantitative and space-resolved distribution of macro, i . e ., K, P, S, and Ca, and micronutrients, i . e ., Fe, Zn, and Mn elemental composition in the cross-sectioned seeds of cowpea ( Vigna unguiculata L.), kidney bean ( Phaseolus vulgaris L.), and soybean (Gl...

Colonization of the xylem of sugarcane by Leifsonia xyli subsp. xyli (Lxx) results in the occlusion of the vessels by a gum-like compound and compromises the elongation of the stalk leading to stunted plants. However, no study has been performed in the apical tissue where the elongation of the stalks initiates at the intercalary meristem (IM). Micr...

Sapindales comprise nine families with a mainly tropical distribution and include numerous species of high economic importance. Members of this order are known for the production of chemical constituents with medicinal properties, such as antioxidant, anti-inflammatory, and antimicrobial activity, as well as species with insecticidal properties. Su...

Plant cells use different structural mechanisms, either constitutive or inducible, to defend themselves from fungal infection. Encapsulation is an efficient inducible mechanism to isolate the fungal haustoria from the plant cell protoplast. Conversely, pectin, one of the polymeric components of the cell wall, is a target of several pectolytic enzym...

X-ray fluorescence spectroscopy (XRF) is a powerful technique for the in vivo assessment of plant tissues. However, the potential X-ray exposure damages might affect the structure and elemental composition of living plant tissues leading to artefacts in the recorded data. Herein, we exposed soybean ( Glycine max (L.) Merrill) leaves to several X-ra...

Citrus relatives are a relevant source of valuable traits for use in citrus breeding, including resistance to diseases such as Huanglongbing (HLB). Resistant rootstocks may impact tree responses to HLB. This requires graft compatibility, which has been poorly investigated within the Aurantioi-deae. In this study, the biometric characteristics and t...

The pathways whereby nickel (Ni) moves within seeds after fertilization of different Ni-seed dressings in soybean seed remains unclear. This study aimed to evaluate the effect of Ni sources, i.e., different size particles, on germination rate of soybean seeds, and uptake/translocation of Ni by roots and seeds in soybean. For this, seeds were treate...

No livro foram publicadas as fotos inscritas no II Concurso: "Um olhar sobre as plantas", fotos classificadas por voto popular.

Root‐knot nematodes (RKNs), particularly Meloidogyne incognita, are among the most damaging and prevalent agricultural pathogens due to their ability to infect roots of almost all crops. The best strategy for their control is through the use of resistant cultivars. However, laborious phenotyping procedures make it difficult to assess nematode resis...

Guava producers in Brazil have reported the occurrence of small, pink spot lesions on the surface of fruits in orchards. Symptomatic fruits were harvested from commercial guava orchards, and 18 monosporic isolates were obtained. All tested isolates were pathogenic to guava fruit and showed colony and conidial characteristics indicative of cercospor...

Sugarcane is widely used as feed for cattle, buffalo, goats, and sheep, primarily during drought periods. Some sugarcane cultivars contain low digestibility fibers, which compromises animal performance. Thus, the present study reports on anatomical, chemical, and elemental analysis along stem internodes of two sugarcane cultivars to better understa...

Sugarcane is widely used as feed for cattle, buffalo, goats, and sheep, primarily during drought periods. Some sugarcane cultivars contain low digestibility fibers, which compromises animal performance. Thus, the present study reports on anatomical, chemical, and elemental analysis along stem internodes of two sugarcane cultivars to better understa...

New approaches for developing disease-resistant genetically modified organisms have included specific targets for gene expression to enhance the chances for pathogen control. Gene expression driven by phloem-derived Citrus sinensis gene promoters could be evaluated and compared with the expression induced by a strong constitutive promoter in the sa...

X-ray fluorescence (XRF) spectroscopy can be used to analyze the distribution and fate of fertilizers applied to plant leaves (foliar fertilization). Our group has been developing methods to adapt commercial and in-house-built portable systems to quantify, in the field, several mineral nutrients in major crops such as soybean, maize, and coffee by...

This article comments on: Li C, Wu J, Pax F, Blamey F, Wang L, Zhou L, Paterson DJ, van der En A, Fernández V, Lombi E, Wang Y, Kopittke PM. 2021. Non-glandular trichomes of sunflower are important in the absorption and translocation of foliar-applied Zn. Journal of Experimental Botany 72, 5079–5092.

The aim of the present study was to evaluate structural and biochemical aspects related to the interaction of resistant (RRIM 937, IAC 502 and 507) and susceptible (RRIM 600) rubber tree clones with C. tamarillo. For such analysis, ultrathin sections of the leaf limb were embedded in historesin and differently stained to verify structural alteratio...

Root-knot nematodes (RKN), particularly Meloidogyne incognita , are among the most damaging and prevalent agricultural pathogens due to their ability to infect roots of almost all crop species, including common bean. The best strategy for their control is through the use of resistant cultivars. However, laborious phenotyping procedures make it diff...

Different from most plant viruses, Brevipalpus mite-transmitted viruses (BTV) cause localized infection, not being able to systemically invade the infected plant. To broaden the specter of the histopathological changes in leaf tissues induced by BTV infection, we examined the tissue organization of leaf lesions caused by the infection of two additi...

Cercosporiosis, caused by Pseudocercospora kaki, is the major foliar disease in persimmon crops. Despite the importance of the disease, we have little information about the interaction of this pathogen with persimmon leaf tissues. Therefore, to elucidate the infection and colonization process in these pathosystem, we investigated this interaction u...

The Asian citrus psyllid, Diaphorina citri Kuwayama, transmits the bacteria Candidatus Liberibacter associated with huanglongbing (HLB), a devastating disease of the citrus industry. The use of genetically modified plants is an alternative to control this vector. Conversely, technology based on RNA interference (RNAi) for silencing specific genes o...

Due to a zinc-deficient diet, about 800,000 children die each year worldwide. This aspect is amended by exploiting foliar fertilization, a useful alternative to improve crop yield and nutritional quality of food crops. The aim of this study was then to investigate the leaf uptake and transport of zinc by soybean (Glycine max (L) Merrill). Plant lea...

In this study, we characterized Zn seed coats adhered on soybean seed surface [Glycine max (L.) Merrill] and then investigated the effects of such coatings on germination and finally monitored the transference of Zn from the coatings to the seedlings. For that, seeds were coated with ZnSO 4 , 40 nm ZnO, and 5 µm ZnO at 4 mg of Zn per kg of seed. Th...

The objective of this work was to investigate the potential of energy dispersive X-ray fluorescence spectrometry for polymeric thin film thickness measurements using univariate and multivariate statistical tools. To this end, nine polymeric films 1.5 to 7.6 μm thick with different composition were used for calibration and validation purposes. The u...

This study aims at investigating the effects of foliar application of aqueous solutions of La3þand Ce3þnitrates on soybean plants (Glycine max). First, we observe that Triton HW 1000 surfactant at 0.01 vol%reduces droplets contact angle and increases their drying time. Under greenhouse conditions, the foliartreatments do not affect chlorophyll cont...

X-ray fluorescence spectroscopy (XRF) is an analytical tool used to determine the elemental composition in a myriad of sample matrices. Due to the XRF non-destructive feature, this technique may allow time-resolved plant tissues analyses under vivo conditions, and additionally the combination with other non-destructive techniques. In this study, we...

Increasing soybean yield is a humankind challenge dependent on several management practices, such as fertilizing and weed control. While glyphosate contributes to controlling weeds, it can interfere with spray mixtures stability and, supposedly, complexing with micronutrients within the plant tissue. This study investigated the effects of glyphosat...

This study aimed at investigating the effects of foliar application of aqueous solutions of La3+ and Ce3+ nitrates on soybean plants (Glycine max). First, we observed that Triton HW 1000 surfactant at 0.01 vol% reduced droplets contact angle and increased their drying time. Under greenhouse conditions, the foliar treatments did not affect chlorophy...

Grapevine rust, caused by Phakopsora euvitis, has recently been introduced in Brazil; however, this disease has spread nationwide, causing significant damage to vineyards. The pathogen reduces CO2 assimilation and photoassimilate availability in host plants. Grapevine rust causes early defoliation and yield reduction, in the subsequent crop, since...

X-ray fluorescence spectroscopy (XRF) is suitable for in vivo analysis of plant tissues. However, potential damage induced by X-ray exposure is a concern. To evaluate this, soybean leaves were irradiated using a 1 mm collimated and 30 µm polycapillary focusing optic X-ray beams at 90% and 10% of maximum instrumental power (45 kV-900 µA and 45 kV-10...

Rust (Phakopsora euvitis) is an important fungal disease in grapevines grown in tropical and subtropical regions. Epidemiological works have been conducted on plant disease resistance, however, little is known about defense mechanisms of resistance to the disease. Leaves of Vitis vinifera cv. Moscato Giallo were inoculated with P. euvitis and lesio...

Austropuccinia psidii, the causal agent of myrtle rust, is a biotrophic pathogen whose growth and development depends on the host tissues. The uredospores of A. psidii infect Eucalyptus by engaging in close contact with the host surface and interacting with the leaf cuticle that provides important chemical and physical signals to trigger the infect...

The emergence of citrus huanglongbing (HLB) has been a constraint for worldwide citrus growers. HLB disease is associated to species of the biothrophic bacteria Candidatus Liberibacter spp. (CaL). In this study, we assessed the transcriptional status of salicylic acid (SA) genes and associated defenses between two contrasting citrus genotypes durin...

1. Introduction Nanomaterials are claimed as a viable alternative for plant nutrient supplementation, due to their nanoscale characteristics and physicochemical properties, which are expected to promote a new range and design of fertilizers [1;2;3]. The reports of ultrastructure of the interaction of nanomaterials and plants are scarce. Copper and...

Despite of the importance of ratoon stunting disease, little is known on the responses of sugarcane to its causal agent, the vascular bacterial endophyte Leifsonia xyli subsp. xyli. The transcriptome and proteome of young plants of a susceptible cultivar with no symptoms of stunting but with relative low and high bacterial titers were compared at 3...

The plant cell wall is known to be the first barrier against plant pathogens. Detailed information about sugarcane cell wall-associated defense responses to infection by the causal agent of smut, Sporisorium scitamineum, is scarce. Herein, (immuno)histochemical analysis of two smut resistant and two susceptible sugarcane cultivars was conducted to...

Entre as doenças que causam prejuízos aos canaviais está o Raquitismo das Soqueiras, causado pela bactéria endofítica Leifsonia xyli subsp. xyli (Lxx). O encurtamento das regiões do entrenó é o sintoma mais importante. O objetivo deste estudo foi analisar estruturalmente o ápice caulinar da cana-de-açúcar ‘CB49-260’ (suscetível) em amostras inocula...

A parede celular vegetal é conhecida como a primeira barreira a agentes fitopatogênicos. No entanto, ainda são escassas as informações sobre as respostas de defesa da cana-de-açúcar associadas à parede celular, em especial, na infecção por S. scitamineum, o fungo causador da doença carvão. Análises estruturais e histoquímicas foram conduzidas em ge...

A ferrugem da videira é uma doença endêmica no sul e sudeste do Brasil. A ferrugem é importante em cultivares de uvas americanas (Vitis labrusca), entretanto, pouco se conhece sobre a doença em videiras europeias (V. vinifera). Folhas de Vitis vinifera cv. Moscato com 30 dias de idade, inoculadas com 104 urediniósporos de Phakopsora euvitis mL-1 ,...

Background and Aims Sugarcane smut is caused by the fungus Sporisorium scitamineum (Ustilaginales/Ustilaginomycotina/Basidiomycota), which is responsible for losses in sugarcane production worldwide. Infected plants show a profound metabolic modification resulting in the development of a whip-shaped structure (sorus) composed of a mixture of plant...