OsCTP1 negatively regulates seedling cold tolerance in rice.

Cold stress poses a significant threat to rice production and grain quality. As a complex quantitative trait, cold tolerance is regulated by multiple genetic loci and environmental factors. Here, we identified OsCTP1 (LOC_Os11g15570), a homolog of the Arabidopsis gene AtSLP2, as a negative regulator of seedling cold tolerance in rice. Subcellular localization and expression analyses showed that OsCTP1 is localized to the endoplasmic reticulum (ER) and mitochondria (Mito), with its transcripts predominantly accumulated in roots, leaves, leaf sheaths, husks, and anthers. Transcriptomic and quantitative analyses further revealed that OsCTP1 likely suppresses the OsWRKY76/OsbHLH148‑OsDREB1B signaling pathway, thereby negatively modulating cold tolerance. Additionally, phenotypic evaluation under exogenous abscisic acid (ABA) treatment suggests that OsCTP1 may function in an ABA‑dependent manner, though the precise molecular mechanism warrants further investigation. In summary, OsCTP1 represents both a valuable genetic resource for elucidating low‑temperature signaling networks and a promising candidate for molecular breeding aimed at improving cold tolerance in rice.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-026-01660-x.