Functional Analyysis Of Two Stress Related Genes In Rice(Oryza Sativa L.)

Abiotic stresses such as salt,drought,heat and low temperature can easily affect crop's development,production and quality.Rice is one of the important cereal,which is especially vital for Asains.Thus,it is of high importance to investigate the molecular mechanism of responses and discover valuable genes under abiotic stresses,in order to gurantee the production and quality of crop.Our research primarlily studied a salt responsive membrane protein OsSRLP1 and a SBP-box transcriptional factor OsSPL2 in the responses of abiotic stresses.1.Plant plasma membrane proteins play critical roles in abiotic stress responses.In present study,we characterized an Oryza sativa Salt Responsive Little Protein 1(OsSRLP1)in rice.OsSRLP1 was constitutively expressed in various rice tissues and at almost all developing stages.Expression analysis indicated that OsSRLP1 was highly induced by high temperature,drought and salt.Overexpression of OsSRLP1 in rice improved free proline content,expression level of OsP5CS gene,and mitigated ion balance under salt stress.OsSRLP1 showed reduced sensitivity to ABA treatment,implying the salt tolerance mediated by OsSRLP1 was likely ABA-independent.Moreover,it was observed that overexpression of OsSRLP1 led to dwarfism phenotype,which was correlated to OsSRLP1 expression level in transgenic rice.In conclusion,OsSRLP1 is a little membrane protein conferring salt tolerance by modulating the ion balance and proline accumulation in rice.2.OsSPL2 belongs to the SBP-box transcription factor family,which was found to be regulated by two small RNAs under drought stress verified by degradome analysis.Thus,we speculated that it may perform function in the regulation and responsive process under drought stress.Real-time analysis revealed that it was constitutively expressed in various tissues at mature stage.OsSPL2-GFP was localized in nuclear,which was consistent with the characteration of transcription factor.We obtained the transgenic OsSPL2Pro:GUS,overexpression,RNAi and CRISPR/Cas9 target editing lines through Agrobacterium tumefaciens-mediated transformation.We detected OsSPL2 expression at the mature stage via G GUS activity assay,and we found that it was mainly expressed in the culm node,leaf shealth and primary panicle.The OsSPL2 overexpression lines exhibited more dispersered architecture,lower plant height and increased grain length.The transactivation activity assays in the yeast and rice protoplast indicated that OsSPL2 was a transcription activator.