Comparative Transcriptomes Reveal the Mitigation Effect of GR24 in Alfalfa Under Drought Stress

Drought stress can cause irreversible damage to plants and long-term water shortage will reduce forage yield. GR24, a kind of synthetic strigolactone, plays an important role in resisting abiotic stress for plants. However, the mitigation mechanism underlying of GR24 under drought stress in alfalfa remained obscure. From a view of physiological point, GR24 could reduce the damage by increasing the content of osmotic adjustment substances and antioxidant enzyme activities in plants. Analysis from the perspective of transcriptome, RNA sequencing was performed to analyze how genes were regulated in response to spraying GR24 under drought stress in alfalfa. There are 72 significant genes in all pairwise comparison combinations. Subsequent bioinformatics analysis showed transcription factors such as PYL/PYR, PP2C, and bZIP families were enriched in the plant signal transduction. GR24 may induce this KEGG pathway to reduce water evaporation by regulating stomata to alleviate drought damage. In summary, our results provide basic information on how some genes are induced by GR24 to respond to drought stress and help to understand the comprehensive mechanism of legume forages after spraying GR24.

Automated summary

This study investigates the mechanism of GR24 in mitigating drought stress in alfalfa. The results show that GR24 can reduce plant damage by increasing the content of osmotic adjustment substances and antioxidant enzyme activities. It also regulates gene expression involved in plant signal transduction and water evaporation, thereby alleviating drought damage.