The RNA editing factor DUA1 is crucial to chloroplast development at low temperature in rice

Low temperature stress hinders plant growth and chloroplast development and can limit the geographic range of cultivars. In rice, japonica cultivars have greater chilling tolerance than indica cultivars, but the molecular mechanism underlying chilling tolerance is unclear. Here, we report an RNA-binding protein, DUA1, cloned from the indica cultivar Dular, which exhibits a deficiency in chloroplast development at an early stage of development under low-temperature conditions. DUA1 shares high sequence homology with the pentatricopeptide repeat family and functions in plastid RNA editing under low-temperature conditions. Our data suggest that DUA1 can bind to the plastid-encoded rps8-182 transcript and disruption of DUA1 activity impairs editing. The RNA editing cofactor WSP1, a partner of DUA1, also participates in chloroplast development at low temperature. Western blot analysis indicates that WSP1 enhances DUA1 stability under low temperatures. DUA1 sequence analyses of rice core germplasm revealed that three major haplotypes of DUA1 and one haplotype showed substantial differences in chlorophyll content under low-temperature conditions. Variation at DUA1 may play an important role in the adaptation of rice to different growing regions.