Abstract
With global climate change leading to an increase in the frequency of
abnormally low temperatures, the yield of rice has significantly
impacted. Due to extensive efforts over the past four decades, many
genes involved in rice cold tolerance have been identified and cloned.
Despite these endeavors, the molecular mechanisms of rice’s response to
cold stress remain unclear. In this study, we used reverse genetics
along with biochemical and molecular biology approaches to characterize
OsRab6a, a small GTP-binding protein. Our findings revealed that OsRab6a
positively regulates rice cold tolerance during both the bud and
seedling stages. The expression of OsRab6a is induced by cold
stress, particularly in seedling roots. Overexpression of OsRab6a
enhances cold tolerance in transgenic rice, whereas the OsRab6a
mutants exhibit the opposite phenotype. Furthermore, OsRab6a physically
interacts with OsRAN2 under cold stress, functioning upstream of OsRAN2.
These results suggest that OsRab6a plays an crucial role in regulating
cold tolerance and the ABA signalling pathway. Our study elucidates the
functional significance of OsRab6a in rice cold tolerance and provides
potential strategies for enhancing the resilience of rice plants to cold
stress.