Natural variation in Brachypodium distachyon responses to combined abiotic stresses

Abstract

SUMMARYThe demand for agricultural production is becoming more challenging as climate change increases global temperature and the frequency of extreme weather events. This study examines the phenotypic variation of 149 accessions of Brachypodium distachyon under drought, heat, and the combination of stresses. Heat alone causes the largest amounts of tissue damage while the combination of stresses causes the largest decrease in biomass compared to other treatments. Notably, Bd21‐0, the reference line for B. distachyon, did not have robust growth under stress conditions, especially the heat and combined drought and heat treatments. The climate of origin was significantly associated with B. distachyon responses to the assessed stress conditions. Additionally, a GWAS found loci associated with changes in plant height and the amount of damaged tissue under stress. Some of these SNPs were closely located to genes known to be involved in responses to abiotic stresses and point to potential causative loci in plant stress response. However, SNPs found to be significantly associated with a response to heat or drought individually are not also significantly associated with the combination of stresses. This, with the phenotypic data, suggests that the effects of these abiotic stresses are not simply additive, and the responses to the combined stresses differ from drought and heat alone.

Stress combination: from genes to ecosystems

“…These authors further identified the oxidative phosphorylation pathway and alternative oxidase 1 as potentially playing a key role in this stress combination. In the third research paper of the special issue, Ludwig et al (2024) studied phenotypic variation in the response of 149 accessions of Brachypodium to heat, drought, and drought combined with heat. Using GWAS and SNP analyses the authors identified different loci associated with plant responses to stress combination, revealing that these responses are not simply the additive effects of drought and heat, as they differ qualitatively from the responses to drought or heat alone.…”