Autophagy deficiency confers freezing tolerance in Arabidopsis thaliana

Plants have evolved multiple strategies to cope with the ever-changing external environment. Autophagy, as one of the crucial mechanisms involved, has been demonstrated to play a pivotal role in plant responses and adaptation to abiotic stresses. However, the precise molecular mechanisms underlying the role of autophagy in mediating cold stress remain to be fully elucidated.

In this study, we demonstrated that autophagy mutants presented increased freezing tolerance under both non-acclimated and cold-acclimated conditions in Arabidopsis. Autophagy positively regulates the expression of anthocyanin biosynthesis-related genes, thereby influencing anthocyanin accumulation in Arabidopsis under low-temperature conditions. Moreover, we found that cold stress directly suppresses the expression of autophagy-related genes and reduces autophagic flux in Arabidopsis. The RNA-seq data revealed that cold-responsive genes were pre-activated in the autophagy mutant atg13ab even before cold treatment. Additionally, we observed constitutive accumulation of the dehydrin protein COR47 in atg13ab mutant.

Taken together, these data suggest that autophagy is a negative regulator of freezing tolerance in Arabidopsis.