Phytohormonal Control over the Grapevine Berry Development

Grapevine (Vitis vinifera) is one of the most important commercial plants since its berries are used for wine production or consumed as fresh fruit or dry fruit. Many studies have focused on berry development and have pointed out the hormonal regulation on the three phases, from early development to maturity. Grapevine fruit has been classified as non-climacteric based on the low levels of ethylene present around véraison, although recent evidence has suggested a role for this hormone during grape berry ripening. The control of different physiological processes depends on a complex integration between environmental cues and endogenous factors, which is mediated by a phytohormone crosstalk. In this chapter, we will focus on phytohormones, their signaling pathways, and their association to berry development in V. vinifera; in particular, we will refer to auxins, abscisic acid, brassinosteroids, ethylene, gibberellins, and cytokinins

Analysis of the grape MYB R2R3 subfamily reveals expanded wine quality-related clades and conserved gene structure organization across Vitis and Arabidopsis genomes

<p>Abstract</p> <p>Background</p> <p>The MYB superfamily constitutes the most abundant group of transcription factors described in plants. Members control processes such as epidermal cell differentiation, stomatal aperture, flavonoid synthesis, cold and drought tolerance and pathogen resistance. No genome-wide characterization of this family has been conducted in a woody species such as grapevine. In addition, previous analysis of the recently released grape genome sequence suggested expansion events of several gene families involved in wine quality.</p> <p>Results</p> <p>We describe and classify 108 members of the grape <it>R2R3 MYB </it>gene subfamily in terms of their genomic gene structures and similarity to their putative <it>Arabidopsis thaliana </it>orthologues. Seven gene models were derived and analyzed in terms of gene expression and their DNA binding domain structures. Despite low overall sequence homology in the C-terminus of all proteins, even in those with similar functions across <it>Arabidopsis </it>and <it>Vitis</it>, highly conserved motif sequences and exon lengths were found. The grape epidermal cell fate clade is expanded when compared with the <it>Arabidopsis </it>and rice MYB subfamilies. Two anthocyanin <it>MYBA </it>related clusters were identified in chromosomes 2 and 14, one of which includes the previously described grape colour locus. Tannin related loci were also detected with eight candidate homologues in chromosomes 4, 9 and 11.</p> <p>Conclusion</p> <p>This genome wide transcription factor analysis in <it>Vitis </it>suggests that clade-specific grape <it>R2R3 MYB </it>genes are expanded while other MYB genes could be well conserved compared to <it>Arabidopsis</it>. <it>MYB </it>gene abundance, homology and orientation within particular loci also suggests that expanded MYB clades conferring quality attributes of grapes and wines, such as colour and astringency, could possess redundant, overlapping and cooperative functions.</p

TRAUCO, a Trithorax-group gene homologue, is required for early embryogenesis in Arabidopsis thaliana

Embryogenesis is a critical stage during the plant life cycle in which a unicellular zygote develops into a multicellular organism. Co-ordinated gene expression is thus necessary for proper embryo development. Polycomb and Trithorax group genes are members of evolutionarily conserved machinery that maintains the correct expression patterns of key developmental regulators by repressing and activating gene transcription. TRAUCO (TRO), a gene homologous to the Trithorax group of genes that can functionally complement a BRE2P yeast mutant, has been identified in Arabidopsis thaliana. It is demonstrated that TRO is a nuclear gene product expressed during embryogenesis, and loss of TRO function leads to impaired early embryo development. Embryos that arrested at the globular stage in the tro-1 mutant allele were fully rescued by a TRO expression clone, a demonstration that the tro-1 mutation is a true loss-of-function in TRO. Our data have established that TRO is the first trithorax-group gene homologue in plants that is required for early embryogenesi

Grapevine Biotechnology: Molecular Approaches Underlying Abiotic and Biotic Stress Responses

Grapevine is one of the most abundant crops worldwide, with varieties destined for fresh and dry consumption, as well as wine production. Unfortunately, grapevine plants are affected by both biotic and abiotic stresses, generating significant economic losses. These conditions can negatively impact grape cultivation at different stages: plant and berry development during pre- and post-harvest, production, fresh fruit processing and export, along with wine quality. Most of the grapevine varieties are susceptible to several pathogens and within this chapter, particular attention is given to fungi (Botrytis cinerea and Erysiphe necator) and viruses, since they are a worldwide concern. Within the latter, special focus is given to the grapevine leafroll disease, a complex and destructive infection. On the other hand, abiotic stress is also relevant in grapevine, and in this chapter it will be exemplified by UV-B radiation and its impact on growth and fruit development, plant adaptive responses and its relationship with the quality of grape berries for winemaking. The main biotic and abiotic grapevine stress factors are reviewed in this chapter, considering a special focus on biotechnological approaches carried out in order to address them and minimize their detrimental consequences

Genetic and histological studies on the delayed systemic movement of Tobacco Mosaic Virus in Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p>Viral infections and their spread throughout a plant require numerous interactions between the host and the virus. While new functions of viral proteins involved in these processes have been revealed, current knowledge of host factors involved in the spread of a viral infection is still insufficient. In <it>Arabidopsis thaliana</it>, different ecotypes present varying susceptibilities to <it>Tobacco mosaic virus </it>strain U1 (TMV-U1). The rate of TMV-U1 systemic movement is delayed in ecotype Col-0 when compared with other 13 ecotypes.</p> <p>We followed viral movement through vascular tissue in Col-0 plants by electronic microscopy studies. In addition, the delay in systemic movement of TMV-U1 was genetically studied.</p> <p>Results</p> <p>TMV-U1 reaches apical leaves only after 18 days post rosette inoculation (dpi) in Col-0, whereas it is detected at 9 dpi in the Uk-4 ecotype. Genetic crosses between Col-0 and Uk-4 ecotypes, followed by analysis of viral movement in F₁and F₂populations, revealed that this delayed movement correlates with a recessive, monogenic and nuclear locus. The use of selected polymorphic markers showed that this locus, denoted <it>DSTM1 </it>(Delayed Systemic Tobamovirus Movement 1), is positioned on the large arm of chromosome II. Electron microscopy studies following the virion's route in stems of Col-0 infected plants showed the presence of curved structures, instead of the typical rigid rods of TMV-U1. This was not observed in the case of TMV-U1 infection in Uk-4, where the observed virions have the typical rigid rod morphology.</p> <p>Conclusion</p> <p>The presence of defectively assembled virions observed by electron microscopy in vascular tissue of Col-0 infected plants correlates with a recessive delayed systemic movement trait of TMV-U1 in this ecotype.</p

Foods with Functional Properties and their Potential Uses in Human Health

Vegetables and fruits have been a part of human diet since ancient times; nevertheless, as countries develop, its population’s feeding habits change and tend to have a diet poor in vegetables and fruits, with well-known consequences. Several food plant products with massive consumption and within the reach of the population are products such as artichoke, leek, hot chili pepper, coriander, kiwifruit, sweet orange, highbush blueberry, and maracuyá to name a few. They have many beneficial properties principally by its content of phytochemicals with high impact on human health, beyond nutritional support. The phytochemicals are bioactive compounds such as vitamins, carotenoids, phenolic acid, and flavonoids, which contribute to antioxidant capacity and as a whole prevent chronic nontransmissible diseases such as: diabetes, high blood pressure, high cholesterol in blood, cardiovascular risks, among others. This relationship between food plant for human consumption and its impacts on human health is discussed in this chapter, highlighting coriander and kiwifruit by its wide range of benefits

Desarrollo de aplicación para el análisis in silico de secuencias promotoras del genoma de vitis vinifera

88 p.La vid es el cultivo frutícola más importante económicamente en Chile y cultivado ampliamente en el mundo. De ella se obtiene un fruto que se utiliza no sólo para la producción de vino, sino también para consumo de fruta fresca, jarabes, jugos, pasas y fabricación de sus derivados tales como cosméticos y aceites. Este frutal ha sido recientemente secuenciado, por lo que su conocimiento acerca de su regulación génica es aún escaso. La regulación de la expresión génica está provista por un complejo mecanismo de control por los cuales las plantas responden a estrés biótico y abiótico y modulan procesos del desarrollo. Esta regulación es coordinada principalmente por mecanismos relacionados a factores de transcripción (TFs). Para comprender el mecanismo de regulación génica de Vitis vinifera, es necesario conocer los sitios donde se unen las secuencias reguladoras de la expresión génica. Si bien algunos sitios web son capaces de realizar búsquedas de este tipo, aún Vitis vinifera no está incorporada. En este trabajo se desarrolló una aplicación para la búsqueda y representación visual de los sitios de unión a factores de transcripción (TFBS), ya sea, caracterizados experimentalmente o de sitios de predicción, en secuencias flanqueantes de Vitis vinifera generando imágenes representativas de los sitios de unión encontrados. No se ha realizado con anterioridad una herramienta para el análisis de TFBS en todo el genoma de Vitis vinifera. Por ello, el desarrollo de esta aplicación es el primer paso para el conocimiento y la comprensión de su expresión génica, reconociendo los posibles sitios de unión de los TFs que regulan la expresión de todos los genes del genom

The grapevine guard cell-related VvMYB60 transcription factor is involved in the regulation of stomatal activity and is differentially expressed in response to ABA and osmotic stress

- Background: Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. - Results: Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during development of grape organs and in response to ABA and drought-related stress conditions. - Conclusions: These results show that VvMYB60 modulates physiological responses in guard cells, leading to the possibility of engineering stomatal conductance in grapevine, reducing water loss and helping this species to tolerate drought under extreme climatic conditions

Pollination: A key event controlling the expression of genes related to phytohormone biosynthesis during grapevine berry formation

Berry formation is the process of ovary conversion into a functional fruit, and is characterized by abrupt changes in the content of several phytohormones, associated with pollination and fertilization. Much effort has been made in order to improve our understanding of berry development, particularly from veraison to post-harvest time. However, the period of berry formation has been poorly investigated, despite its importance. Phytohormones are involved in the control of fruit formation; hence it is important to understand the regulation of their content at this stage. Grapevine is an excellent fleshy-fruit plant model since its fruits have particularities that differentiate them from those of commonly studied organisms. For instance, berries are prepared to cope with stress by producing several antioxidants and they are non-climacteric fruits. Also its genome is fully sequenced, which allows to identify genes involved in developmental processes. In grapevine, no link has been established between pollination and phytohormone biosynthesis, until recently. Here we highlight relevant findings regarding pollination effect on gene expression related to phytohormone biosynthesis, and present results showing how quickly this effect is achieved

Inspection of the grapevine BURP superfamily highlights an expansion of RD22 genes with distinctive expression features in berry development and ABA-mediated stress responses

The RESPONSIVE TO DEHYDRATION 22 (RD22) gene is a molecular link between abscisic acid (ABA) signalling and abiotic stress responses. Its expression has been used as a reliable ABA early response marker. In Arabidopsis, the single copy RD22 gene possesses a BURP domain also located at the C-terminus of USP embryonic proteins and the beta subunit of polygalacturonases. In grapevine, a RD22 gene has been identified but putative paralogs are also found in the grape genome, possibly forming a large RD22 family in this species. In this work, we searched for annotations containing BURP domains in the Vitis vinifera genome. Nineteen proteins were defined by a comparative analysis between the two genome predictions and RNA-Seq data. These sequences were compared to other plant BURPs identified in previous genome surveys allowing us to reconceive group classifications based on phylogenetic relationships and protein motif occurrence. We observed a lineage-specific evolution of the RD22 family, with the biggest expansion in grapevine and poplar. In contrast, rice, sorghum and maize presented highly expanded monocot-specific groups. The Vitis RD22 group may have expanded from segmental duplications as most of its members are confined to a region in chromosome 4. The inspection of transcriptomic data revealed variable expression of BURP genes in vegetative and reproductive organs. Many genes were induced in specific tissues or by abiotic and biotic stresses. Three RD22 genes were further studied showing that they responded oppositely to ABA and to stress conditions. Our results show that the inclusion of RNA-Seq data is essential while describing gene families and improving gene annotations. Robust phylogenetic analyses including all BURP members from other sequenced species helped us redefine previous relationships that were erroneously established. This work provides additional evidence for RD22 genes serving as marker genes for different organs or stresses in grapevine