Acyl carrier protein OsMTACP2 mediated wax biogenesis is essential for rice cold tolerance at the booting stage (PRJCA019009)

Low temperatures occurring at rice (Oryza sativa L.) booting stage often result in yield loss by impeding male reproductive development. However, the underlying mechanisms by which rice responds to cold at this stage remain largely unknown. Here, we identified MITOCHONDRIAL ACYL CARRIER PROTEIN 2 (OsMTACP2), which mediates lipid metabolism involved in the cold response at rice booting stage. Loss-of-function of OsMTACP2 leads to compromised cold tolerance, hindering the development of anther cuticle and pollen wall, resulting in abnormal anther morphology, reduced pollen fertility, and lower seed setting. OsMTACP2 is highly expressed in tapetal cells and microspores during anther development, with the encoded protein localizing to both mitochondria and cytoplasm. Comparative transcriptomic analysis revealed differential expression of genes related to lipid metabolism between the wild-type Longdao 5 (LD5) and osmtacp2-1 mutant in response to cold. Through lipidomic analysis, we demonstrate that wax esters, which are the primary lipid components of anther cuticle and pollen walls, function as cold-responsive lipids. Their levels increased dramatically in the wild type but not in the osmtacp2-1 mutant when exposed to cold. These results suggest that OsMTACP2-mediated wax ester biosynthesis is essential for cold tolerance in rice at the booting stage.