The Roles Of Transcription Factor Gene OsPHR3 On The Utilization Of Phosphate And Nitrogen In Rice

Phosphorus,an essential macronutrient element for plant growth and development,is broadly participating in various of plant life activities.However,the phosphorus in soil has a low availability,which is a major barrier for crop production in many agricultural systems.Ammonium(NH4+)and nitrate(NO3-)are two main forms of nitrogen which are uptaken by plant roots.In soil,the nitrogen is easy to run off,and its concentration is quite low.So the nitrogen supply can’t meet the need for crops.Rice is one of the most important cereal crops feeding a large segment of the world’s population.In addition,phosphorus and nitrogen are two major factors limiting crop growth in the world.Therefore,research on the funtion of OsPHR3 with regard to rice nutrients uptake and translocation is extreme importance for understanding of the mechanism and breeding new rice variety.In this study,the transcription factor gene OsPHR3 is considered as the object of research.We take the Nipponbare,a rice model breed,as the study material.Identifying the expression characteristics of the gene by bioinformatics analysis and expression pattern analysis.Using Tosl7 insertion in mutants and over-expression materials to verify OsPHR3’s function.These provided some solid studying basis for the efficient absorbing and utilizing of phosphorus and nitrogen in rice as well as the modern molecular breeding technology.What the main results we obtained are as follows:1.The bioinformatics analysis informed that OsPHR3 was located on the 2nd chromosome of rice.The full length of cDNA was 1404bp,which could encode 467 amino acids.Sequence alignment between genomic and cDNA sequences showed that OsPHR3 had seven exons and six introns,have MYB-CC and MYB-HTH domain.And Real-time RT-PCR analysis indicated that the shoots and roots of the OsPHR3 strain were subjected to the phosphorus deficiency,but the roots was decrease under nitrogen deficiency.2.With the deep research and analysis of mutant and over-expression material of OsPHR3,we could find that the OsPHR3 can promote the absorption and transportation of phosphorus and nitrogen to the shoots during the seeding stage.Compared with the wild type strain,the available phosphorus and total phosphorus in roots and shoots of the mutant material had no significant change.While in the over-expression strain of OsPHR3,the phosphorus content increased obviously in shoots and roots.32Pi and 15N isotopic experiments revealed the consistent conclusion,that the absorption and transport rate in over-expression lines are faster than wild type plants under phosphorus and nitrogen deficiency conditions.3.Pot experiments demonstrated that the OsPHR3 involved in the transport of phosphate and nitrogen during the reproductive growth period of rice,and promoting the yield per plant of rice.The knock-out lines had no significant difference between wild type plants in the development process of rice,the plant height and panicle length have merely changed in mature period.Compared with wild type strain,the effective tillers and yield increased by 14.7%,11.9%per plant when the OsPHR3 was over-expressed.While the total phosphorus and total nitrogen content in seeds enhanced significantly.In conclusion,the over-expression of OsPHR3 may promoting the absorption and improving the phosphorus and nitrogen content of shoots in rice and promoting the rice yield per plant.