Knock out of the annexin gene OsAnn3 via CRISPR/Cas9-mediated genome editing decreased cold tolerance in rice

Plant annexins are Ca2+-dependent phospholipid-binding proteins and exist as multigene families in plants. They are implicated in the regulation of plant development as well as protection from environmental stresses. In this study, the rice annexin gene OsAnn3 knockout was performed via the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR associated proteins) mediated genome editing. Thus, mutant plantlets were successfully obtained. We identified cold tolerance phenotype of T-1 mutant lines from T0 biallelic mutants using the 4 similar to 6A degrees C for 3 days cold treatment. The results showed that REC (the relative electrical conductivity) of T-1 mutant lines was increased, and the survival ratio of T-1 mutant lines was decreased dramatically compared with the wild type after the exposure to cold treatment. It was suggested that OsAnn3 was involved in cold tolerance of rice.