The Effection Of Phosphate Transporter On Nodulation And Nitrogen Fixtion In Legume

Symbiotic nitrogen fixation by legume was the most important source of nitrogen in agricultural ecosystem.Phosphorus is an essential mineral element for plant and it was uptaked and transported by phosphate transporter.Phosphate transporters As PT6 and Gigm PT were identified from Astragalus sinicus and G.margarita(BEG34)in our previous work,respectively.The function of As PT6 and the effection of Gigm PT on nodulation were explored in this research,respectively.The main results were as follow:1.As PT6 was expressed in root,stem and leaves in A.sinicus,with the highest expression in shoot.When inoculated with 7653 R,the expression of As PT6 was increased significantly in the root and nodules.2.The promoter-GUS analysis showed that As PT6 was expressed in the vascular tissue of roots and nodule as well as in the junction between root and nodule,implying that As PT6 played a role in the transportation of phosphate(Pi)in plant,especially from root to nodules.3.Overexpression and RNAi of As PT6 significant affected the nodulation and nitrogenase activity of nodules.This suggested that As PT6 played a role in phosphorus transport from root to nodule.As PT6 could promote the nodulation and nitrogen fixation in A.sinicus.4.The growth and nodulation of A.sinicus,M.trucutula and soybean were limited when inoculated with 7653R(Gigm PT),1021(Gigm PT)and HH103(Gigm PT).The results of increasing the amount of inoculum showed that biomass,nodule number and nitrogenase activity of M.truncatula and soybean didn't affected by Gigm PT.However,there still had significant differences in numbers of nodule and nitrogenase activity in A.sinicus when inoculated 7653R(Gigm PT)under high phosphorus concentration.5.The growth curve of the rhizobia indicated that Gigm PT limited the growth of rhizobia,especially in 7653 R.