This study reveals that while brassinosteroid receptors BRI1 and BRL3 both impact drought response, BRL3 promotes drought tolerance in sorghum through osmotic protection, whereas BRI1 signaling is associated with drought susceptibility due to growth-related sensitivities.
Keywords: BRI1, Brassinosteroids, DAP‐seq, Drought, Phenylpropanoid, Sorghum bicolor
Beyond being a scientific breakthrough, this discovery has the potential to significantly enhance food security in climate-vulnerable regions – Matus
One of the most surprising findings was how well these plants maintained photosynthesis during a severe drought,” says Juan Fontanet-Manzaneque, first author of the study. “Normally, drought causes a decrease in photosynthesis, which leads to stunted growth and lower yields. “But these mutants were still performing at a higher level, which could mean better yields under drought conditions. – Fontanet
Drought is a critical environmental challenge that greatly impacts global crop yields, surpassing the losses caused by pathogens. Sorghum, a crop known for its resilience to drought, still suffers substantial yield reductions during critical growth phases, such as the anthesis and grain-filling stages. Research efforts have focused on enhancing drought tolerance in sorghum by studying stay-green traits—characteristics that delay leaf senescence under drought conditions. However, the genes controlling these traits are not fully understood. Brassinosteroids (BRs), a class of plant steroid hormones, have garnered attention due to their significant roles in plant growth and development. Despite evidence showing that exogenous BRs can enhance drought tolerance in certain crops, studies reveal contrasting results with genetically modified BR pathways, underscoring the complexity of BR-mediated drought responses.
Researchers from Centre for Research in Agricultural Genomics (CRAG), I2SysBio (Universitat de València-CSIC), Max-Planck-Institute of Molecular Plant Physiology, Center of Plant Systems Biology and Biotechnology and University of Copenhagen investigated how the roles of BR receptors, specifically BRI1 and BRL3, illustrate how distinct BR pathways impact drought responses. BRI1 loss-of-function mutants exhibit drought avoidance, likely due to reduced growth, while overexpression of BRL3 enhances drought tolerance through osmotic protection mechanisms. These findings suggest that BRL3, rather than BRI1, might drive beneficial drought-resilient traits. The authors also characterized downstream BR-effectors such as BES1. Furthermore, studies highlight the interplay between BR and reactive oxygen species (ROS) signaling, suggesting a complex crosstalk that may underpin stress responses. For example, BR-induced ROS production aids in osmotic stress resistance in certain plants. These insights into BR signaling pathways reveal potential for selective BR pathway modulation in sorghum to improve drought resilience without compromising growth, with implications for breeding more resilient crop varieties.
SorghumBase examples:
Brassinosteroid signalling pathway genes
Reference:
Fontanet-Manzaneque JB, Laibach N, Herrero-García I, Coleto-Alcudia V, Blasco-Escámez D, Zhang C, Orduña L, Alseekh S, Miller S, Bjarnholt N, Fernie AR, Matus JT, Caño-Delgado AI. Untargeted mutagenesis of brassinosteroid receptor SbBRI1 confers drought tolerance by altering phenylpropanoid metabolism in Sorghum bicolor. Plant Biotechnol J. 2024 Sep 26. PMID: 39325724. doi: 10.1111/pbi.14461. Read more
Related Project Websites:
- Caño-Delgado paper at Center for Research in Agricultural Genomics (CRAG): https://www.cragenomica.es/research-groups/brassinosteroid-signaling-plant-development-and-adaption-climate-change