A β‐ketoacyl carrier protein reductase confers heat tolerance via the regulation of fatty acid biosynthesis and stress signaling in rice

• DOI: 10.1111/nph.17619
• Publication Date: 2021-07-14T14:21:25Z
• Authors: Fei Chen; Guojun Dong; Fang Wang; Yingqi Shi; Jiayu Zhu; Yanli Zhang; Banpu Ruan; Yepin Wu; Xue Feng; Chenchen Zhao; Miing T. Yong; Paul Holford; Dali Zeng; Qian Qian; Limin Wu; Zhong‐Hua Chen; Yanchun Yu
• Keywords: Thermotolerance; 2. Zero hunger; 0303 health sciences; Research; Fatty Acids; Oryza; 15. Life on land; Plants, Genetically Modified; Droughts; 03 medical and health sciences; Gene Expression Regulation, Plant; Stress, Physiological; XXXXXX - Unknown; Carrier Proteins; Oxidoreductases; Phylogeny; Plant Proteins

Summary Heat stress is a major environmental threat affecting crop growth and productivity. However, the molecular mechanisms associated with plant responses to heat are poorly understood. Here, we identified stress‐sensitive mutant, hts1 , in rice. HTS1 encodes thylakoid membrane‐localized β‐ketoacyl carrier protein reductase (KAR) involved de novo fatty acid biosynthesis. Phylogenetic bioinformatic analysis showed that probably originated from streptophyte algae evolutionarily conserved land plants. Thermostable predominantly expressed green tissues strongly induced by stress, but less responsive salinity, cold drought treatments. An amino substitution at A254T causes significant decrease KAR enzymatic activity and, consequently, impairs synthesis lipid metabolism especially under stress. Compared wild‐type, mutant exhibited heat‐induced higher H 2 O accumulation, larger Ca 2+ influx mesophyll cells, more damage membranes chloroplasts. Also, disrupted signaling depresses transcriptional activation of HsfA2s downstream target genes. We suggest critical for underpinning membrane stability, chloroplast integrity tolerance