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Descripción
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| Indole-3-acetic acid (IAA), the main naturally occurring auxin in plants, is an essential plant hormone that has been associated with the regulation of many aspects of plant development and growth (Hentrich et al., 2013a; Woodward & Bartel, 2005). Nonetheless, insight into the role of auxin in plant stress responses is just emerging. Recently, Hentrich et al. (2013a) demonstrated that exogenous application of methyl jasmonate (MeJA) or endogenous production of jasmonic acid (JA), a hormone with a prevalent role in plant defense to necrotrophic pathogens and insect herbivores (Studham & MacIntosh, 2012), is sufficient to trigger IAA production through the up-regulation of YUCCA9; a flavinlike monooxygenase gene whose product is involved in the rate-limiting step of the IPyA pathway of auxin biosynthesis (Mashiguchi et al., 2011; Stepanova et al., 2011; Won et al., 2011; Zhao 2010). Using whole-genome transcriptomic analysis of wild-type Col-0 and 35S::YUCCA9 (YUC9ox) Arabidopsis transgenic lines, which exhibit increased IAA levels (Hentrich et al., 2013b), we revealed a group of XYLOGLUCAN ENDOTRANS-GLYCOSYLASE/HYDROLASE (XTH) cell wall-related genes that were up-regulated in the YUC9ox mutant. In addition, our histochemical analyses and quantitative cell wall assays performed in mature stems showed that, in comparison to Col-0, the overexpression of YUC9 leads to stimulated xylem and interfascicular fibers differentiation, as well as increased lignification, which is enriched in H-lignin deposition. These alterations are likely to be triggered by elevated ethylene (ET) levels, as we demonstrated that ET production is significantly increased in the YUC9ox line. On the other hand, the analysis of differential gene expression levels in YUC9ox provided first evidence for the existence of an IAA-dependent negative feedback loop that controls chitin-triggered cellular defenses, and an implication of YUC9 in water deficit responses. Our experiments exposing YUC9 mutants to the two-spotted spider mite Tetranychus urticae and to drought conditions revealed that the overexpression of the YUC9 gene rendered the mutant plants more resistant toward T.urticae and more tolerant to drought. Taken together, the presented findings suggest that the induction of YUC9 gene expression plays a role in the regulation of the complex response to herbivore predators and possibly to water deprivation. | |
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Internacional
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No |
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Nombre congreso
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XIV Reunión de Biología Molecular de Plantas. |
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Tipo de participación
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970 |
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Lugar del congreso
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Salamanca |
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Revisores
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Si |
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ISBN o ISSN
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0000-0000 |
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DOI
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Fecha inicio congreso
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04/06/2018 |
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Fecha fin congreso
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06/06/2018 |
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Desde la página
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115 |
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Hasta la página
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115 |
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Título de las actas
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XIV Reunión de Biología Molecular de Plantas. Libro de Resumenes |