The m6 A reader MhYTP2 regulates MdMLO19 mRNA stability and antioxidant genes translation efficiency conferring powdery mildew resistance in apple.

N6 -methyladenosine (m6 A) reader protein plays an important role in trichome morphology, developmental timing and morphogenesis in Arabidopsis. However, the function of m6 A readers in plant-microbe interaction remains unclear. Here, a Malus YTH-domain family protein MhYTP2 was initially characterized as an m6 A reader. MhYTP2 overexpression increased mRNA m6 A modification level and translation efficiency. The m6 A in the exon regions appeared to destabilize the mRNAs, whereas m6 A in the untranslated regions positively correlated with the associated mRNA abundance. MhYTP2 overexpression enhanced apple powdery mildew resistance, possibly by rapidly degrading the bound mRNAs of MdMLO19 and MdMLO19-X1 and improving the translation efficiency of the antioxidant genes. To conclude, the results shed light on the apple m6 A profile, the effect of MhYTP2 on m6 A profile, and the m6 A roles in MdMLO19 and MdMLO19-X1 mRNAs stability and glutamate dehydrogenase 1-like MdGDH1L mRNA translation efficiency.