OsRLCK102 Regulates Development And XA21-mediated Immunity In Rice

RLCKs(receptor-like cytoplasmic kinases)belong to a kinase family without extracellular structures and transmenbrane domains in plant.RLCKs have been reported to involved in plant development,hormone response and plant immunity.There are 379 OsRLCKs predicted in rice.Based on their structures,these OsRLCKs can be divided into several different subfamilies,including OsRLCK I,OsRLCK II,OsRLCKVI,OsRLCK VII and etc.After analyzed the expression profiles of these OsRLCK genes using the data available from the database of microarray,we found that the expression of the OsRLCK 102 encoding a protein from OsRLCKVII subfamily was induced by biotic and abiotic stress.We then demonstrated that OsRLCK 102 was involved in regulating development and immune response in rice through genetic,pathogenic,molecular approaches.The main results are listed below:1.Clustering analysis revealed that OsRLCK 102 belonged to OsRLCKVII subfamily and shared high identities with BIK1 and PBL1 in Arabidopsis.2.Transcriptional analysis suggested that OsRLCK102 was expressed in various tissues with a preference in rice leaves and panicles.3.Sub-cellular localization analysis uncovered that the fluorescent signals in rice leaf protoplasts transformed with the plasmid 35S-OsRLCK102-GFP spread in thecytosols indicating that OsRLCK 102 is localized in rice cytosols,and is likelyfunctions in the cytoplasm.4.Using RNA interference(RNAi)approach,we obtained eight independent transgenic lines in Kitaake and thirteen in Xa21 silenced for OsRLCK102 that can be used for subsequent analysis of phenotype and functions.5.Transgenic plants in silence of OsRLCK102 displayed semi-dwarfed stature with increased lamina joint angles and lower rates of seed setting.These plants also exhibited higher sensitivity to the hormone brassinolide(BR)than did the wild type Kitaake.6.Inoculation with pathogen revealed that silencing of OsRLCK102 was able to compromise Xa21-mediated but not Xa3-mediated resistance to Xanthomonas oryzae pv.oryzae(Xoo).Further analysis suggested that the plants in silence of OsRLCK102 displayed similar full resistance to Xoo strain PXO86 and diverse strains of Magnaporthe oryzae(M.oryzae).Collectively,our study suggests that,OsRLCK102 negatively regulates plant development through BR signaling and positively modulates immunity via XA21-mediated signaling,respectively,in rice.