Lectin receptor kinase OsLecRK-S.7 is required for pollen development and male fertility

Pollen grains are covered by exine that protects the pollen from stress and facilitates pollination. Here we isolated a male sterile mutants13283in rice exhibiting aborted pollen with abnormal exine and defective aperture. The mutant gene encodes a novel plasma membrane-localized legume-lectin receptor kinase that we named OsLecRK-S.7.OsLecRK-S.7was expressed at different levels in all tested tissues and throughout anther development.In vitrokinase assay showed OsLecRK-S.7 capable of autophosporylation. Mutation ins13283(E560K) and mutation of the conserved ATP binding site (K418E) both knocked out the kinase activity. Mass spectrometry showed Thr(376), Ser(378), Thr(386), Thr(403), and Thr(657)to be the autophosphorylation sites. Mutation of individual autophosphorylation site affected thein vitrokinase activity to different degrees, but did not abolish the gene function in fertility complementation.oslecrk-s.7mutant plant overexpressingOsLecRK-S.7recovered male fertility but showed severe growth retardation with reduced number of tillers, and these phenotypes were abolished by E560K or K418E mutation. The results indicated that OsLecRK-S.7 was a key regulator of pollen development.