Interactive effects of water limitation and elevated temperature on the physiology, development and fitness of diverse accessions of Brachypodium distachyon

Abstract

An enduring question in plant physiology and evolution is how single genotypes of plants optimize performance in diverse, often highly variable, environments. We grew 35 natural accessions of the grass Brachypodium distachyon in four environments in the glasshouse, contrasting soil water deficit, elevated temperature and their interaction. We modeled treatment, genotype and interactive effects on leaf-level and whole-plant traits, including fecundity. We also assessed the relationship between glasshouse-measured traits and parameters related to climate at the place of origin. We found abundant genetic variation in both constitutive and induced traits related to plant-water relations. Most traits showed strong interaction between temperature and water availability, and we observed genotype-by-environment interaction for several traits. Notably, leaf free proline abundance showed a strong effect of genotype × temperature × water. We found strong associations between phenology, biomass and water use efficiency (WUE) with parameters describing climate of origin. Plants respond to multiple stressors in ways not directly predictable from single stressors, underscoring the complex and trait-specific mechanisms of environmental response. Climate-trait correlations support a role for WUE and phenology in local adaptation to climate in B. distachyon.

Phenotypic and metabolic plasticity shapes life‐history strategies under combinations of abiotic stresses

“…is a model system for Pooid cereal and forage species that has been used to study environmental stress responses such as: drought, extreme temperature, salinity, and nutrient availability (reviewed by Scholthof, Irigoyen, Catalan, & Mandadi, 2018). However, except for a few studies (e.g., Barhoumi et al, 2010;Des Marais, Lasky, Verslues, Chang, & Juenger, 2017; Shaar-Moshe, Blumwald, & Peleg, 2017), most of these experiments involved single stresses at early vegetative stages. In order to study B. distachyon acclimation strategies to environmental stresses, information on life-history and phenological data are required since they determine the coordination of environmental conditions with developmental transitions, the occurrence of the stress and the expected acclimation strategy (Des Marais & Juenger, 2016).…”

Unique Physiological and Transcriptional Shifts under Combinations of Salinity, Drought, and Heat

“…is a wild temperate model grass with close evolutionary relationships to wheat and barley (International Brachypodium Initiative, 2010). In recent years, B. distachyon has emerged as a powerful model plant to accelerate improvement of stress related traits in cereal crops (Lv et al, 2014;Priest et al, 2014;Shaar-Moshe et al, 2015;Des Marais et al, 2017). Here, we employed a system biology approach to study the morpho-physiological and transcriptional patterns associated with acclimations of B. distachyon to combinations of salinity, drought, and heat stresses.…”

Trait plasticity and covariance along a continuous soil moisture gradient

“…). Mean leaf RWC for plants in the 10% tail of soil water content was 85.21% which is drier than that observed in the dry treatment of DesMarais et al (Des Marais et al 2017). Additional observations made during the experiment such as leaf rolling, another symptom of dehydration stress, was evident in plants at the lowest water treatment by the end of the dry down period.…”

“…Five genotypes of each species were studied to characterize patterns of variation in plant traits across an environmental gradient: Brachypodium distachyon inbred lines ABR2, Adi-10, Bd21, Bd3-1, and Koz-1 and Brachypodium sylvaticum inbred lines Ain-1, Ast-1, Kry-1, Osl-1, Vel-1. For each species, these genotypes represent a range of geographical origins and phenotypic diversity (Steinwand et al 2013;Des Marais et al 2017). Both species are self-compatible and each of the lines used here have been maintained as inbred lines for greater than six generations (Vogel et al 2009;Steinwand et al 2013); as such, experimental replicates may be considered nearly homozygous.…”

“…Quantitative genetic variation in myriad drought resistance traits have been observed in natural populations and laboratory model systems. In particular, natural populations of Brassicaceae species (including Arabidopsis thaliana) and Brachypodium harbor variation both constitutive and inducible traits mediating plant-water relations, including water use efficiency (Des Marais et al 2012Marais et al , 2017Edwards et al 2012;Greenham et al 2017), leaf chemistry (Kesari et al 2012;Des Marais et al 2017), leaf anatomy (Skirycz et al 2011;Verelst et al 2013;Dittberner et al 2018), rootshoot biomass partitioning (Des Marais et al 2012Marais et al , 2017, and many others (Verslues and Juenger 2011;Edwards et al 2012;Juenger 2013;Luo et al 2016;Yarkhunova et al 2016;Lenk et al 2019). Among the numerous plant traits that can and have been measured, few have been studied more extensively than specific leaf area (SLA -often reported as it's inverse, leaf mass per area or LMA).…”