The tomato mutant ars1 (altered response to salt stress 1) identifies an R1‐type MYB transcription factor involved in stomatal closure under salt acclimation

Abstract

SummaryA screening under salt stress conditions of a T-DNA mutant collection of tomato (Solanum lycopersicum L.) led to the identification of the altered response to salt stress 1 (ars1) mutant, which showed a salt-sensitive phenotype. Genetic analysis of the ars1 mutation revealed that a single T-DNA insertion in the ARS1 gene was responsible of the mutant phenotype. ARS1 coded for an R1-MYB type transcription factor and its expression was induced by salinity in leaves. The mutant reduced fruit yield under salt acclimation while in the absence of stress the disruption of ARS1 did not affect this agronomic trait. The stomatal behaviour of ars1 mutant leaves induced higher Na + accumulation via the transpiration stream, as the decreases of stomatal conductance and transpiration rate induced by salt stress were markedly lower in the mutant plants. Moreover, the mutation affected stomatal closure in a response mediated by abscisic acid (ABA). The characterization of tomato transgenic lines silencing and overexpressing ARS1 corroborates the role of the gene in regulating the water loss via transpiration under salinity. Together, our results show that ARS1 tomato gene contributes to reduce transpirational water loss under salt stress. Finally, this gene could be interesting for tomato molecular breeding, because its manipulation could lead to improved stress tolerance without yield penalty under optimal culture conditions.

A Member of the 14-3-3 Gene Family in Brachypodium distachyon, BdGF14d, Confers Salt Tolerance in Transgenic Tobacco Plants

“…Salt stress facilitates the accumulation of endogenous ABA, which is a vital regulator of stomatal closure to reduce the amount of Na + transported from roots to shoots and to minimize water loss via transpiration (Kim et al, 2010; Campos et al, 2016). The differences in morphology and physiology observed above between the transgenic lines and WT plants under salt stress prompted us to investigate whether the overexpressing BdGF14d in tobacco plants affected the stomatal closure in seedlings treated with NaCl or ABA.…”

“…The adaptive responses to abiotic stresses as mediated by ABA include stomatal closure and the transcription of a number of related genes involved in the stress tolerance process (Choi et al, 2000; An et al, 2008; Wang R.S. et al, 2011; Geilfus et al, 2015; Campos et al, 2016). The 14-3-3 proteins seem to participate in ABA-mediated stomatal closure (Cotelle and Leonhardt, 2016): there was less stomatal aperture in leaves of the BdGF14d -overexpression plants than in those of WT under the ABA treatment ( Figure 7 ); this implicates BdGF14d in ABA-mediated stomatal closure.…”

A collection of enhancer trap insertional mutants for functional genomics in tomato

“…Likewise, the screening of this T‐DNA mutant collection has allowed us to identify other tagged mutants. Among them are vegetative inflorescence ( mc‐vin ) and altered response to salt stress 1 ( ars1 ) mutants (Campos et al ., ; Yuste‐Lisbona et al ., ). All together, these results strongly support the usefulness of enhancer trapping as an efficient strategy for functional genomics, allowing for the discovery of novel genes and regulatory elements.…”

Multifaceted regulatory function of tomato SlTAF1 in the response to salinity stress

“…Enhanced leaf transpiration and, therefore, water loss leads to massive transport of Na + to leaves (Campos et al, 2016). Enhanced leaf transpiration and, therefore, water loss leads to massive transport of Na + to leaves (Campos et al, 2016).…”

“…Optimising transpiration by controlling stomatal aperture is amongst the main determinants for reducing the rate of Na + transport to shoots, thereby leading to salt acclimation over time (Shabala, 2013;Campos et al, 2016). Optimising transpiration by controlling stomatal aperture is amongst the main determinants for reducing the rate of Na + transport to shoots, thereby leading to salt acclimation over time (Shabala, 2013;Campos et al, 2016).…”