Arabidopsis species deploy distinct strategies to cope with drought stress.

M Bouzid,F He,A P M Weber,J De Meaux,R E Häusler,T Mettler-Altmann,G Schmitz

doi:10.1093/aob/mcy237

M Bouzid, F He + Show 5 more

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https://doi.org/10.1093/aob/mcy237

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Abstract

Background and AimsWater limitation is an important determinant of the distribution, abundance and diversity of plant species. Yet, little is known about how the response to limiting water supply changes among closely related plant species with distinct ecological preferences. Comparison of the model annual species Arabidopsis thaliana with its close perennial relatives A. lyrata and A. halleri, can help disentangle the molecular and physiological changes contributing to tolerance and avoidance mechanisms, because these species must maintain tolerance and avoidance mechanisms to increase long-term survival, but they are exposed to different levels of water stress and competition in their natural habitat.MethodsA dry-down experiment was conducted to mimic a period of missing precipitation. The covariation of a progressive decrease in soil water content (SWC) with various physiological and morphological plant traits across a set of representative genotypes in A. thaliana, A. lyrata and A. halleri was quantified. Transcriptome changes to soil dry-down were further monitored.Key ResultsThe analysis of trait covariation demonstrates that the three species differ in the strategies they deploy to respond to drought stress. Arabidopsis thaliana showed a drought avoidance reaction but failed to survive wilting. Arabidopsis lyrata efficiently combined avoidance and tolerance mechanisms. In contrast, A. halleri showed some degree of tolerance to wilting but it did not seem to protect itself from the stress imposed by drought. Transcriptome data collected just before plant wilting and after recovery corroborated the phenotypic analysis, with A. lyrata and A. halleri showing a stronger activation of recovery- and stress-related genes, respectively.ConclusionsThe response of the three Arabidopsis species to soil dry-down reveals that they have evolved distinct strategies to face drought stress. These strategic differences are in agreement with the distinct ecological priorities of the stress-tolerant A. lyrata, the competitive A. halleri and the ruderal A. thaliana.

Highlights

All physiological and cellular plant aspects depend on water, so limitation in its supply is a major abiotic stress restricting plant growth and crop yield (Stebbins, 1952; Boyer, 1982; Bohnert et al, 1995; Bray, 1997; Lambers et al, 1998; Bray et al, 2000)
Under well-watered conditions, constitutive physiological differences between A. lyrata and A. halleri can influence their potential to face limiting soil water content (SWC)
Stomata were larger in A. lyrata compared with A. halleri (M1: P-value

Summary

Introduction

All physiological and cellular plant aspects depend on water, so limitation in its supply is a major abiotic stress restricting plant growth and crop yield (Stebbins, 1952; Boyer, 1982; Bohnert et al, 1995; Bray, 1997; Lambers et al, 1998; Bray et al, 2000). Water limitation is a crucial determinant of the distribution, abundance and diversity of plant species (Hoffmann and Sgró, 2011). Adult plants can draw from this toolbox to tolerate a certain degree of dehydration in vegetative organs (Ludlow, 1989; Shinozaki and Yamaguchi-Shinozaki, 2007). This tolerance strategy relies on osmotic adjustment via the accumulation of an array of solutes, such as amino acids, sugars or dehydrins (Close, 1996). The expression of heat shock proteins, chaperones or late embryogenesis abundant (LEA) proteins can further help to protect the cell against damage imposed by low internal water potential (Ingram and Bartels, 1996; Reddy et al, 2004; Yue et al, 2006; Szabados, 2010)

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