Abstract
N6-methyladenosine (m(6)A) methylation functions as a vital post-transcriptional and epigenetic modification in higher plants regulated by α-ketoglutarate-dependent dioxygenases (ALKBH). However, the role of ALKBH genes in oriental melon (Cucumis melo L.) fruit ripening has not been explored. Therefore, we treated oriental melon with an exogenous m(6)A demethylase inhibitor (mechlorfenamic acid) then analyzed endogenous ethylene production and ripening-related indicators to explore the effects of m(6)A methylation on ripening. Bioinformatics and real-time quantitative PCR analyses were used to determine the impact of ALKBH genes on key ethylene synthesis gene expression. Treatment effectively inhibited endogenous ethylene production, firmness changes, and soluble solid contents, thereby extending fruit ripening. Eight ALKBH gene family members belonging to five major groups were identified in the melon genome. All members were expressed in ripening fruits, with different expression patterns during ripening. CmALKBH6, CmALKBH7, and CmALKBH8 expression was inhibited by an ethylene inhibitor (1-methylcyclopropene). The transient overexpression (OE) of CmALKBH8 in oriental melon led to the increased expression of the ethylene synthesis genes CmACS1, CmACS2, and CmACO1. In summary, the ethylene-regulated gene CmALKBH8 may participate in oriental melon fruit ripening regulation by modulating the methylation levels of ethylene synthesis-related genes. These findings help us better understand how m(6)A methylation regulates melon ripening.