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

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
DOI: 10.1111/nph.17619 Publication Date: 2021-07-14T14:21:25Z
ABSTRACT
Summary Heat stress is a major environmental threat affecting crop growth and productivity. However, the molecular mechanisms associated with plant responses to heat stress are poorly understood. Here, we identified a heat stress‐sensitive mutant, hts1, in rice. HTS1 encodes a thylakoid membrane‐localized β‐ketoacyl carrier protein reductase (KAR) involved in de novo fatty acid biosynthesis. Phylogenetic and bioinformatic analysis showed that HTS1 probably originated from streptophyte algae and is evolutionarily conserved in land plants. Thermostable HTS1 is predominantly expressed in green tissues and strongly induced by heat stress, but is less responsive to salinity, cold and drought treatments. An amino acid substitution at A254T in HTS1 causes a significant decrease in KAR enzymatic activity and, consequently, impairs fatty acid synthesis and lipid metabolism in the hts1 mutant, especially under heat stress. Compared to the wild‐type, the hts1 mutant exhibited heat‐induced higher H2O2 accumulation, a larger Ca2+ influx to mesophyll cells, and more damage to membranes and chloroplasts. Also, disrupted heat stress signaling in the hts1 mutant depresses the transcriptional activation of HsfA2s and the downstream target genes. We suggest that HTS1 is critical for underpinning membrane stability, chloroplast integrity and stress signaling for heat tolerance in rice.
SUPPLEMENTAL MATERIAL
Coming soon ....
REFERENCES (85)
CITATIONS (51)