Map-based Cloning And Functional Analysis Of Gene OsRLK2 Regulating Phosphorus Absorption In Rice

Phosphorus is one of the mass elements necessary for plant growth and development,and plays an important role in plants.Phosphorus participates in a series of processes such as material synthesis,energy conversion,and signal transmission during plant growth and development.The fixation of phosphorus to the soil results in a very low concentration of soluble phosphorus in the soil,so the efficiency of phosphorus uptake and utilization by plants is also very low.The absorption and transport of phosphorus mainly depends on the phosphorus transporter in plants,so the phosphorus transporter plays an important role in maintaining the phosphorus balance and normal development in plants.By screening the library of rice T-DNA insertion mutants in our laboratory,we obtained a mutant of phosphorus accumulation,partial tip necrosis,plant dwarf,and named it rlk2.The mutant rlk2 was based on the indica rice variety Nipponbare.There was no significant difference in the available phosphorus content between the mutant to the wild type.The effective phosphorus content in the mutant was significantly higher than the wild type after the tillering stage.The phenotypes such as dwarfing of plants and necrosis of leaf tips gradually appeared.A statistical experiment of the genetic population and the field phenotype revealed that the rlk2 mutation was a recessive homozygous mutation.By constructing a targeting population and using map-based cloning technique,we cloned a gene encoding a receptor-like protein kinase from the rice genome and named it OsRLK2.OsRLK2 is expressed in both underground and above-ground tissues.Receptor-like protein kinases are a very important signal regulator in plants.The structure of the receptor-like protein kinase mainly includes an extracellular receptor domain,a transmembrane domain and an intracellular protein kinase domain.Subcellular localization experiments indicate that the OsRLK2 protein is localized on the plasma membrane.Through the yeast screening experiment,we obtained a phosphorus transporter OsPT8 that interacts with OsRLK2.Further experiments demonstrated the interaction between OsRLK2 to OsPT8.As a high-affinity phosphotransporter,OsPT8 is expressed in all tissues of rice and is an important transporter of phosphorus uptake and transport in rice.OsRLK2 has a post-translational modification effect on OsPT8 by in vitro phosphorylation assay.OsRLK2 may regulate the uptake and transport of phosphorus by OsPT8 through phosphorylation of OsPT8.This experiment preliminarily describes the molecular mechanism of the receptor-like kinase OsRLK2 regulating phosphorus uptake and transport,which is of great significance for improving the utilization efficiency of phosphorus in rice and maintaining the balance of phosphorus in rice.