Downregulation of GhALKBH10B improves drought tolerance through increasing the stability of photosynthesis related- and ABA signaling pathway genes in cotton

N6-methyladenosine (m6A) is a post-transcriptional modification found in eukaryotic mRNAs. It is installed and removed by methyltransferases and demethylases, respectively. Recent studies have demonstrated that alpha-ketoglutarate-dependent dioxygenase homolog 10B (ALKBH10B) is an mRNA m6A eraser affecting floral transition and responding to abiotic stresses in Arabidopsis thaliana. However, the roles of m6A eraser proteins, especially cotton GhALKBH10B, in plant adaptation to abiotic stresses are largely unknown. In this study, we aimed to determine the role of GhALKBH10B in the response of cotton to drought stress. The m6A level significantly increased in GhALKBH10B-silenced plants compared to that in the control plants. Seedling growth and survival rate of GhALKBH10B-silenced plants were enhanced under drought stress, while heterologous expression of GhALKBH10B in Arabidopsis thaliana attenuates the drought tolerance. Notably, drought-tolerant phenotypes of GhALKBH10B-silenced plants were correlated with the increased mRNA stability of photosynthesis-related genes and GhSnRK2;3 which is a key regulator in ABA-dependent pathway under both normal and dehydration conditions. In addition, GhALKBH10B interacts with a RNA binding protein GhSERBP1(Hyaluronic / mRNA binding family HABP4_PAI-RBP1) both in vitro and in vivo and silencing GhSERBP1 decreased the drought tolerance in cotton. Collectively, these findings indicate that GhALKBH10B-mediated m6A demethylation affects the transcript levels of photosynthesis-related genes and GhSnRK2;3, which are important for survival of cotton in response to drought stress. This will provide important clues for revealing the novel molecular mechanism at the epi-transcriptomic level in drought response and provide key candidate genes for cotton drought-tolerant breeding in the future.