Abstract
BackgroundABA-mediated processes are involved in plant responses to water deficit, especially the control of stomatal opening. However in grapevine it is not known if these processes participate in the phenotypic variation in drought adaptation existing between genotypes. To elucidate this question, the response to short-term water-deficit was analysed in roots and shoots of nine Vitis genotypes differing in their drought adaptation in the field. The transcript abundance of 12 genes involved in ABA biosynthesis, catabolism, and signalling were monitored, together with physiological and metabolic parameters related to ABA and its role in controlling plant transpiration.ResultsAlthough transpiration and ABA responses were well-conserved among the genotypes, multifactorial analyses separated Vitis vinifera varieties and V. berlandieri x V. rupestris hybrids (all considered drought tolerant) from the other genotypes studied. Generally, V. vinifera varieties, followed by V. berlandieri x V. rupestris hybrids, displayed more pronounced responses to water-deficit in comparison to the other genotypes. However, changes in transcript abundance in roots were more pronounced for Vitis hybrids than V. vinifera genotypes. Changes in the expression of the cornerstone ABA biosynthetic gene VviNCED1, and the ABA transcriptional regulator VviABF1, were associated with the response of V. vinifera genotypes, while changes in VviNCED2 abundance were associated with the response of other Vitis genotypes. In contrast, the ABA RCAR receptors were not identified as key components of the genotypic variability of water-deficit responses. Interestingly, the expression of VviSnRK2.6 (an AtOST1 ortholog) was constitutively lower in roots and leaves of V. vinifera genotypes and higher in roots of V. berlandieri x V. rupestris hybrids.ConclusionsThis study highlights that Vitis genotypes exhibiting different levels of drought adaptation differ in key steps involved in ABA metabolism and signalling; both under well-watered conditions and in response to water-deficit. In addition, it supports that adaptation may be related to various mechanisms related or not to ABA responses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0778-4) contains supplementary material, which is available to authorized users.
Highlights
abscisic acid (ABA)-mediated processes are involved in plant responses to water deficit, especially the control of stomatal opening
This study highlights that Vitis genotypes exhibiting different levels of drought adaptation differ in key steps involved in ABA metabolism and signalling; both under well-watered conditions and in response to water-deficit
Genotype-specific transpiration responses to water-deficit Four days after withholding irrigation, average pre-dawn shoot water potential was significantly reduced in all genotypes with the exception of SO4 (Fig. 1a)
Summary
ABA-mediated processes are involved in plant responses to water deficit, especially the control of stomatal opening. In grapevine it is not known if these processes participate in the phenotypic variation in drought adaptation existing between genotypes. The diversity within Vitis genus provides a good resource to select from in order to protect against phylloxera and be adapted to various environmental conditions Among these conditions, water availability is Rossdeutsch et al BMC Plant Biology (2016) 16:91 differences in drought tolerance among grapevine genotypes in the field [1] (and references cited therein). Among Vitis genotypes, differences in stomatal sensitivity to drought have been associated with ABA concentration in xylem sap or leaves [15], and there is variability in stomatal sensitivity to ABA [16,17,18]
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