Comparative genomic analysis of N6-methyladenosine regulators in nine rosaceae species and functional characterization in response to drought stress in pear

N6-methylated adenine(m6A)is an emerging epigenetic marker in eukaryotic organisms that plays an important role in biological functions and in enriching genetic information.m6A exerts these functions via the dynamic interplay among m6A writers,erasers,and readers.However,little is known about the underlying mechanisms of m6A in plant growth and stress responses.Here,we identified 276 masked m6A regulators from nine Rosaceae species(Pyrus bretschneideri,Pyrus betulifolia,Pyrus communis,Malus domestica,Fragaria vesca,Prunus avium,Prunus mume,Prunus persica,and Rubus occidentalis).We classified and named these genes in more detail based on phylogenetic and synteny analysis.The expansion of m6A regulators in Maloideae was dated back to the recent whole-genome duplication(WGD)in Rosaceae.Based on the expression pattern analysis and gene structure analysis of m6A regulators,m6A was shown to be a significant factor in regulating plant development and resistance.In addition,PbrMTA1-silenced pear plants displayed significantly reduced drought tolerance and chlorophyll content,as well as increased electrolyte leakage and concentrations of malondialdehyde and H2O2.