Raúl Herrera

Raúl Herrera
Universidad de Talca · Instituto of Biological Science (ICB)

PhD

About

136
Publications
42,537
Reads
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2,033
Citations
Citations since 2017
33 Research Items
1277 Citations
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
Additional affiliations
January 1990 - April 2015
Universidad de Talca
Position
  • Professor (Full)
Education
January 1992 - December 1994
University of Reading
Field of study
  • Plant Molecular Biology
March 1983 - December 1987
Universidad de Concepcion
Field of study
  • Biochemistry

Publications

Publications (136)
Article
Quantitative real-time PCR (RT-qPCR) is used extensively in gene expression studies. For adequate comparisons, the identification and use of reliable reference genes are crucial. Nevertheless, the availability of such genes in strawberry species is limited and has yet to be described for the Chilean strawberry, Fragaria chiloensis. In this study, t...
Article
Full-text available
Fragaria chiloensis (Chilean strawberry) is a native species that produces fruit with an exotic pinkish color and a fruity aroma. It has a non-climacteric pattern of fruit ripening, and it is the mother of the commercial Fragaria x ananassa. The ripening of F. chiloensis fruit seems stimulated by ABA, and a complete set of genes participate in its...
Article
Aquaporins are an ancient family of membrane channel proteins present in all eukaryotes and most prokaryotes, and apart from water, allow the transport of neutral solutes and organic compounds through the pore. These proteins are essential role differentially expressed during ripening in Fragaria vesca fruits. Fv PIP2-1a is intensively expressed in...
Article
Full-text available
Arabinogalactan proteins (AGPs) are members of a family of proteins that play important roles in cell wall dynamics. AGPs from inclined pines were determined using JIM7, LM2, and LM6 antibodies, showing a higher concentration in one side of the stem. The accumulation of AGPs in xylem and cell wall tissues is enhanced in response to loss of tree ste...
Article
Full-text available
Phenolic compounds with antioxidant properties have risen in interest due to their benefits for human health. Fragaria chiloensis is a native wild berry species from Chile that develops a white/pink receptacle and white flesh at the ripe stage. Changes in color parameters, anthocyanins, secondary metabolites (phenolics, flavonoids), and total antio...
Article
Full-text available
Fragaria chiloensis is a native species from Chile and has interesting attributes such as good taste, aroma, and exotic white color. As the maternal relative of commercial strawberry, it is interesting to understand its ripening physiology. Changes in physiological parameters (size, soluble solids, acidity, and firmness) were followed during the de...
Article
Two interesting plants within the Chilean flora (wild and crop species) can be found with a history related to modern fruticulture: Fragaria chiloensis subsp. chiloensis (Rosaceae) and Vasconcellea pubescens (Caricaceae). Both species have a wide natural distribution, which goes from the Andes mountains to the sea (East-West), and from the Atacama...
Article
Full-text available
Xyloglucan endotransglycosylase/hydrolases (XTHs) are cell wall enzymes with hydrolase (XEH) and/or endotransglycosylase (XET) activities. As they are involved in the modification of the xyloglucans, a type of hemicellulose present in the cell wall, they are believed to be very important in different processes, including growth, development, and fr...
Article
Full-text available
The molecular mechanisms underlying inclination responses in trees are unclear. In this study, we identified a MADS-box transcription factor differentially expressed early after inclination in the stems of Pinus radiata D. Don. PrMADS10 has a CDS of 582 bp and encodes a group II MADS-box transcription factor. We measured highest accumulation of thi...
Article
Fragaria chiloensis (L.) Mill. fruit has exotic organoleptic properties however commercialization is a challenge due to its fast and intensive softening. Texture modifications associated to ripening are related to cell wall metabolism. Main cell wall polysaccharides metabolized in F. chiloensis fruit are pectins, being rhamnogalacturonan I (RG-I) a...
Article
Deschampsia antarctica inhabits the maritime territory of Antarctica and South Patagonia. It grows under very harsh environmental conditions. The survival of this species in low freezing temperatures and under high levels of UV-B radiation may constitute some of the most remarkable adaptive plant responses and suggests that this plant possesses gen...
Article
Expansins are cell wall proteins associated to several processes, including changes in the cell wall during ripening of fruit, which matches softening of the fruit. We have previously reported an increase in expression of specific expansins transcripts during softening of Fragaria chiloensis fruit. Here we characterized three α-expansins. Their ful...
Article
Changes in fruit texture taking place during ripening, described as softening, are mainly due to alterations in structure and/or composition of the cell wall. Several non-covalent interactions between the three carbohydrate polymers of the cell wall, cellulose, pectins and hemicellulose, and many structural proteins and ions, enable a complex struc...
Article
Full-text available
The response to inclination in plants is an attractive and extensively studied biological process. The most commonly held theory proposes a differential growth in stem tissue due to unequal auxin redistribution. Further evidence proposed that flavonoids act as molecular regulators of auxin distribution or flux. It is well known that flavonoids affe...
Article
Xyloglucan endotransglycosylase/hydrolases (XTH) may have endotransglycosylase (XET) and/or hydrolase (XEH) activities. Previous studies confirmed XET activity for PrXTH1 protein from radiata pine. XTHs could interact with many hemicellulose substrates, but the favorite substrate of PrXTH1 is still unknown. The prediction of union type and energy s...
Article
Plants respond to the loss of vertical growth re-orientating their affected organs. In trees, this phenomenon has received the scientific attention due to its importance for the forestry industry. Nowadays it is accepted that auxin distribution is involved in the modulation of the tilting response, but how this distribution is controlled is not ful...
Article
Full-text available
Fragaria chiloensis is a strawberry endemic from Chile with attractive white-pink fruit, pleasant aroma and taste. However, this fruit has a limited post-harvest period due to fast softening. Several transcription factors (TFs) are involved in the regulation of fruit ripening, and members of the NAC family have been implicated in cell wall remodeli...
Article
The equilibrium between protein synthesis and degradation is key to maintaining efficiency in different physiological processes. The proteinase inhibitor cystatin regulates protease activities in different developmental and physiological contexts. Here we describe for the first time the identification and the biological function of the cysteine pro...
Article
Full-text available
The response to inclination in plants is a well-studied biological process where hormones have been implicated in the modulation of vertical growth restoration. Studies on the involvement of auxins in differential growth of plant stems have resulted in the hypothesis that differential growth in stem tissue is due to unequal auxin re-distribution. I...
Article
Full-text available
Background Fragaria vesca or ‘woodland strawberry’ has emerged as an attractive model for the study of ripening of non-climacteric fruit. It has several advantages, such as its small genome and its diploidy. The recent availability of the complete sequence of its genome opens the possibility for further analysis and its use as a reference species....
Article
Xyloglucan endotransglycosylase/hydrolases (XTH) may have endotransglycosylase (XET) and/or hydrolase (XEH) activities. Previous studies suggest that XTHs might play a key role in ripening of Fragaria chiloensis fruit as FcXTH1 transcripts increase as fruit softens. FcXTH1 protein sequence contains a conserved N-glycosylation site adjacent to catal...
Article
The fungus Penicillium purpurogenum degrades plant cell walls by the action of cellulolytic, xylanolytic and pectinolytic enzymes. The α-D-galactosidase is one of the enzymes which may act on pectin degradation. This enzyme has several biotechnological and medical applications. The aim of this work was to better understand the molecular mechanism o...
Article
Fruit of Carica papaya L. (papaya) has several post-harvest problems mainly caused by quick softening that reduces its shelf life. This softening is directly related to degradation and modification of cell wall oligosaccharides. Therefore, it is important to study, understand and, eventually, regulate the softening process of this fruit to increase...
Article
Plants have the ability to reorient their vertical growth when exposed to inclination. This response can be as quick as 2 h in inclined young pine (Pinus radiata D. Don) seedlings, with over accumulation of lignin observed after 9 days s. Several studies have identified expansins involved in cell expansion among other developmental processes in pla...
Poster
Full-text available
Gravity plays an important role as environmental stimulus, particularly responding to loss of verticality, and triggering differential cellular responses. Molecular events in response to inclination promote cell wall modifications, such as, synthesis of hormones like Auxins and Ethylene, and gene expression of transcription factors (TFs) as MYB and...
Article
Full-text available
It has been argued that specific salivary proteins could have a protective effect against caries, but data from the many available studies are rather contradictory. The purpose of this study was to analyze whether there is a relationship between protein concentration, electrophoretic profile and concentration of salivary IgA and the presence or abs...
Article
White Chilean strawberries (Fragaria chiloensis) are non-climacteric fruits, with an exotic colour and aroma. In order to discover genes involved in the development of these fruits, we identified a fragment of a gene encoding a Late Embryogenesis Abundant (LEA) domain protein, FcLDP1, that was expressed in early stages of fruit development, particu...
Article
Full-text available
Aroma and flavor are important factors of fruit quality and consumer preference. The specific pattern of aroma is generated during ripening by the accumulation of volatiles compounds, which are mainly esters. Alcohol acyltransferase (AAT) (EC 2.3.1.84) catalyzes the esterification reaction of aliphatic and aromatic alcohols and acyl-CoA into esters...
Data
Main distances established between ligands and catalytic residues at the SAAT active site during 5 ns of MD simulations. (A) Distances between the oxygen atom of the alcohols and the carbonylic carbon of the acetyl-CoA (dHO•••O = C-AcCoA); (B) Distances between the oxygen atom of the alcohols and the Nε of the His157 (dHO•••Nε-His157). Distances fo...
Data
Evaluation of non-local environment interactions performed by the atomic empirical mean force potential ANOLEA on each heavy atom in the SAAT model. Negatives energies (on green) represent favorable interactions of the respective residue. (TIFF)
Data
RMSD values of SAAT–acetylCoA–octanol (upper left), SAAT–acetylCoA–hexanol (upper right), SAAT–acetylCoA–benzylalcohol (bottom left) and SAAT–acetylCoA–butanol complexes (bottom right), measured during the 5ns equilibration molecular dynamics simulation. On black is represented the protein backbone, on red the acetylCoA substrate and on green the r...
Data
Sequence alignment between Vironina synthase (Rauvolfia serpentina) and the AAT of Fragaria ananassa. The highly conserved motifs HXXXD and DFGWG are highlighted in yellow. (TIFF)
Data
2D representation of vdW interactions, between octanol and nonpolar groups in SAAT. The purple arrow represent the hydrogen bond interaction made between the hydroxyl group of octanol and the Nε of His157. (TIFF)
Data
Schematic and 3D representations of the solvent channel in SAAT protein. The upper scheme emphasizes the size difference in volume between the front and back faces of the channel. The former allows the binding of acetyl-CoA and the latter the binding of alcohol substrates. Catalytic residues are represented in sticks and the channel as a molecular...
Data
Average distances for electrostatic interactions made between residues Asp166, Arg177, Arg180 and Asn182 with respect acetyl-CoA during a 5 ns MD simulation (see also Fig 2). (PDF)
Article
Full-text available
Abstract Stem reorientation in response to inclination in trees has commanded the attention of the research community widely, but the molecular mechanisms of the response are still unknown. The most accepted theory is auxin redistribution in affected tissues. Flavonols have been reported as potent inhibitors of polar auxin transport; however, no re...
Book
Full-text available
Entendemos que hacer universidad, más allá de la investigación y la docencia, es utilizar sus espacios para imaginarla. En tardes de conversación nos surgió la inquietud de plasmar nuestras disímiles miradas sobre la universidad. Por ello, agradecemos a los académicos que aceptaron nuestra invitación a participar en esta aventura cuyo propósito es...
Article
Full-text available
Symposium 20 - PABMB: Teaching biochemistry in a connected world Chair: Miguel Castanho, Universidade de Lisboa, PortugalAbstract:The new paradigm of higher education requires new teaching strategies to meet the learning objectives of biochemistry courses. Teaching biochemistry in the current state of science and society requires a special motivati...
Article
Alcohol acyltransferases (AAT) catalyze the esterification reaction of alcohols and acyl-CoA into esters in fruits and flowers. Despite the high divergence between AAT enzymes, two important and conserved motifs are shared: the catalytic HxxxD motif, and the DFGWG motif. The latter is proposed to play a structural role; however, its function remain...
Article
Fruit softening is associated to cell wall modifications produced by a set of hydrolytic enzymes and proteins. Expansins are proteins with no catalytic activity, which have been associated with several processes during plant growth and development. A role for expansins has been proposed during softening of fruits, and many fruit-specific expansins...
Article
Full-text available
Background The development of a high throughput genome scanning platform for the cultivated strawberry, Fragaria ×ananassa, is necessary for enabling marker assisted breeding in this allo-octoploid species. Short-read sequencing of nineteen octoploid strawberry accessions was used to identify single nucleotide polymorphism (SNPs) and indels after a...
Chapter
Full-text available
Anthocyanins are one of the most abundant flavonoid compounds. These pigments, naturally present in fruits and vegetables, provide color and promote health benefits to consumers due to their antioxidant capacity. To date, more than 600 anthocyanins have been identified in nature, all coming from six anthocyanidin aglycones derived from flavylium ba...
Article
Fragaria chiloensis ssp. chiloensis has two native botanical forms. Fruits from both botanical forms, Fragaria chiloensis ssp. chiloensis f. chiloensis (native white strawberry) and f. patagonica (native red strawberry), were collected from Bio-Bio Region, and a comparative study in the biosynthesis and pigment accumulation was performed from achen...
Article
Full-text available
The cell wall is a dynamic structure that can be modified by different conditions during growth. Stem inclina- tion induces biochemical changes and chemical modifications in the cell walls of conifers driving plant stem reorientation. Different enzymes take part in cell wall remodeling, including xyloglucan endotransglycosylase/hydrolase (XTH). Thi...
Chapter
Forest trees cover 30% of the earth's land surface, providing renewable fuel, wood, timber, shelter, fruits, leaves, bark, roots, and are source of medicinal products in addition to benefits such as carbon sequestration, water shed protection, and habitat for 1/3 of terrestrial species. However, the genetic analysis and breeding of trees has lagged...
Article
Full-text available
Secondary xylem (wood) is formed through an intricate biological process that results in a highly variable final product. Studies have focused on understanding the molecular events for wood formation in conifers. In this process environmental, ontogenic and genetic factors influence variation in wood characteristics, including anatomical, chemical...
Article
Aroma in Vasconcellea pubescens fruit is determined by esters, which are the products of catalysis by alcohol acyltransferase (VpAAT1). VpAAT1 protein structure displayed the conserved HxxxD motif facing the solvent channel in the center of the structure. To gain insight into the role of these catalytic residues, kinetic and site-directed mutagenes...
Article
In conifers, relationship between ethylene and the response to inclination are not well understood. The aim of this work was to study the consequence for the application of 2-chloroethyl phosphonic acid (ethephon), compound able to release ethylene, in one-year-old Pinus radiata D. Don seedlings subjected to inclination. In plants exposed to inclin...
Article
Fragaria chiloensis (L.) Mill. is one of the parent of the commercial strawberry, and has emerged as a variety for breeding purposes. Botrytis cinerea infection is one of the most important infectious diseases for cultivated plant species, producing important losses in yield as well as fruit quality. Plants and fruits of Chilean strawberry have sho...
Article
Alcohol acyltransferases (AAT) play a key role in ester biosynthesis. In Cucumis melo var. cantalupensis, AATs are encoded by a gene family of four members (CmAAT1-4). CmAAT1, CmAAT3 and CmAAT4 are capable of synthesizing esters, being CmAAT1 the most active. CmAAT2 is inactive and has a 268-alanine residue instead of a threonine which is present i...
Article
Full-text available
Teaching biochemistry in the current state of science and society requires a special motivation for learning, especially for students where Biochemistry is one of the courses on their careers. The traditional way of teaching, based on the teacher-student relationship, mostly unidirectional, does not fulfil the needs imposed in this era. Considering...
Article
Full-text available
Loss of verticality in conifers affects the nor-mal wood development by inducing changes and chemical modifications in tree stems called compression wood. It is known that ethylene influences the response during this abnormal wood-forming process. The expression pattern of genes involved in the ethylene biosynthesis pathway during gravitropic respo...
Article
Tropical papaya (Carica papaya) and mountain papaya (Vasconcellea pubescens) fruits are characterised for their strong and particular aroma. The aroma of both fruits is different and dominated by esters, which are synthesised by alcohol acyltransferases (AATs). The ability to produce esters is contrasting, V. pubescens (VpAAT1) being a very active...
Conference Paper
Introduction: Human saliva is essential to preserve oral health, acting like a buffer to the acids generated by the oral microflora. It has been demonstrated that the salivary buffer capacity presents a trend to the increase after the consumption of a chamomilla infusion in comparison with a basal sample and increases significantly in comparison to...
Article
The gravitropic response in trees is a widely studied phenomenon, however understanding of the molecular mechanism involved remains unclear. The purpose of this work was to identify differentially expressed genes in response to inclination using a comparative approach for two conifer species. Young seedlings were subjected to inclination and sample...
Article
Aroma in fruits is an important attribute of quality determined by a set of volatile compounds. Tropical papaya (Carica papaya) and mountain papaya (Vasconcellea pubescens) fruit are characterized for their strong and particular aroma. Their aroma is different and dominated by esters, compounds which are synthesized by alcohol acyltransferases (AAT...
Article
Aroma in fruits is an important attribute of quality determined by a set of volatile compounds. Tropical papaya (Carica papaya) and mountain papaya (Vasconcellea pubescens) fruit are characterized for their strong and particular aroma. Their aroma is different and dominated by esters, compounds which are synthesized by alcohol acyltransferases (AAT...
Article
Chilean strawberry (Fragaria chiloensis) is a berry fruit with excellent organoleptic properties, however its fast softening limits its commercialization. Fruit softening is related to cell wall degradation and several related enzymes have been studied in strawberries, including xyloglucan endotransglycosylase/hydrolase (XTH). Two XTH genes have be...