Barley HOMOCYSTEINE METHYLTRANSFERASE 2 confers drought tolerance by improving polyamine metabolism

• DOI: 10.1093/plphys/kiad333
• Publication Date: 2023-06-10T14:08:05Z
• Authors: Cheng-Wei Qiu; Yue Ma; Qing-Qing Wang; Man-Man Fu; Chengdao Li; Yizhou Wang; Feibo Wu
• Keywords: 2. Zero hunger; Plant Breeding; 13. Climate action; Stress, Physiological; Drought Resistance; Hordeum; Spermine; 15. Life on land; Homocysteine S-Methyltransferase; Reactive Oxygen Species; 6. Clean water; Droughts

Abstract Drought stress poses a serious threat to crop production worldwide. Genes encoding homocysteine methyltransferase (HMT) have been identified in some plant species response abiotic stress, but its molecular mechanism drought tolerance remains unclear. Here, transcriptional profiling, evolutionary bioinformatics, and population genetics were conducted obtain insight into the involvement of HvHMT2 from Tibetan wild barley (Hordeum vulgare ssp. agriocrithon) tolerance. We then performed genetic transformation coupled with physio-biochemical dissection comparative multiomics approaches determine function this protein underlying HvHMT2-mediated expression was strongly induced by tolerant genotypes natural contributed through S-adenosylmethionine (SAM) metabolism. Overexpression promoted HMT synthesis efficiency SAM cycle, leading enhanced increased endogenous spermine less oxidative damage growth inhibition, thus improving water status final yield. Disruption led hypersensitivity under treatment. Application exogenous reduced accumulation reactive oxygen (ROS), which mitoguazone (inhibitor biosynthesis), consistent association metabolism ROS scavenging adaptation. Our findings reveal positive role key plants, providing valuable gene not only for breeding drought-tolerant cultivars also facilitating schemes other crops changing global climate.