Nanopore RNA direct sequencing identifies that m6A modification is essential for sorbitol-controlled resistance to
Zhihua Song1, Qing Yang1, Biying Dong1
1State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing 100083, China; The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China; Ecological Observation and Research Station of Heilongjiang Sanjiang Plain Wetlands, National Forestry and Grassland Administration, Beijing Forestry University, Beijing 100083, China.
Abstract:
Sorbitol, a main photosynthate and transport carbohydrate in all tree fruit species in Rosaceae, acts as a signal controlling resistance against Alternaria (A.) alternata in apple by altering the expression of the MdNLR16 resistance gene via the MdWRKY79 transcription factor. However, it is not known if N6-methyladenosine (m6A) methylation of the mRNAs of these genes participates in the process. Here, we found that decreased sorbitol synthesis in apple leaves leads to a transcriptome-wide reduction in the m6A modification, with fewer transcripts containing two or more methylation sites. We identified two methyltransferases, MdVIR1 and MdVIR2, that respond to sorbitol and A. alternata inoculation and positively control resistance to A. alternata. MdVIR1 and MdVIR2 act on MdWRKY79 and MdNLR16 mRNAs, and the resulting m6A modification stabilizes their mRNAs and improves translation efficiency. These data identify that m6A modification through MdVIR1 and MdVIR2 methyltransferases is essential for sorbitol-controlled resistance to A. alternata.
