A rice glutamyl-tRNA synthetase modulates early anther cell division and patterning

Abstract

Aminoacyl-tRNA synthetases (aaRSs) play a housekeeping role in cellular protein synthesis, but little is understood about how these aaRSs are involved in organ development. Here we report that, in the model crop rice (Oryza sativa), a glutamyl-tRNA synthetase (OsERS1) maintains proper somatic cell organization and limits the over-proliferation of male germinal cells during early anther development. The expression of OsERS1 is specifically detectable in meristematic layer 2-derived (L2-d) cells of the early anther, and osers1 exhibits over-proliferation and disorganization of L2-d cells, producing fused lobes and extra germinal cells in early anthers. The conserved biochemical function of OsERS1 in ligating glutamate to tRNAGlu, is enhanced by its cofactor OsARC (aminoacyl-tRNA synthetase co-factor). Further, metabolomics profiling reveals that OsERS1 is an important node for multiple metabolic pathways, indicated by the accumulation of amino acids and TCA components in osers1 anthers. Notably, the anther defects of osers1 are causally associated with the abnormal accumulation of H2O2, which can reconstitute the osers1 phenotype when applied to wild type. Collectively, this finding represents the first example on how aaRSs affect male organ development in plants, likely through protein synthesis, metabolic homeostasis and redox status.