Morphological And Physiological Responses Of Pueraria Lobata To Low Phosphorus And Its Proteomic Mechanis

Phosphorus is the basic nutrient element for plant growth and reproduction,and its deficiency exists widely in many ecosystems and agricultural land.It is of far-reaching significance to explore the response and regulation mechanism of plants to low phosphorus.It not only has a far-reaching impact on the sustainable development of agriculture and animal husbandry,but also has a positive contribution to maintaining the overall situation of ecological balance and sustainable development.Pueraria lobate is of great value in feeding,medicine and ecology,but the research on its physiological response and molecular mechanism under low phosphorus stress is still lacking.Therefore,in this study,Kudzu（Pueraria lobate）vine from three different provenances,namely Kudzu vine from Australia,Kudzu vine from Jiangsu and Kudzu vine from Guizhou,were cultured at 0.5（normal phosphorus）and 0.05（low phosphorus）mmol·L^-1,respectively,and the phenotypic,physiological and biochemical analysis and mechanism of Kudzu vine cultured for 5 days,10 days and 20 days were studied.The main results are as follows:（1）Phenotypic evaluation of low phosphorus tolerance of Pueraria lobata:The plant height,stem diameter,fresh weight of aerial part,fresh weight of underground part,dry weight of aerial part and dry weight of underground part of Pueraria lobata from three provenances all decreased with the decrease of phosphorus concentration.It is worth noting that the root-shoot ratio of Pueraria lobata from Australia and Pueraria lobata from Jiangsu increased on the 5th and 10th day of low phosphorus treatment,while the root-shoot ratio of Pueraria lobata from Guizhou was on the 5th and 10th day of low phosphorus treatment.Among them,on the 5th day of low phosphorus treatment,the root-shoot ratio of Pueraria lobata increased by 50%（P<0.05）,which indicated that its aboveground biomass was transported to the underground under low phosphorus stress,so as to obtain phosphorus to the maximum extent by changing the root structure of the underground,and so was Pueraria lobata in Jiangsu,but under the same stress time,the sensitivity of Pueraria lobata in Australia was greater than that of Pueraria lobata in Jiangsu and Pueraria lobata in Guizhou.The results showed that low phosphorus stress induced the accumulation of biomass in the roots of pueraria lobata,while the growth of aerial parts was hindered.Compared with the other two kinds of kudzu vine,kudzu vine in Australia has stronger ability of root structure remodeling,and the more developed its root system,the stronger its resistance to low phosphorus environment.（2）Physiological and biochemical evaluation of low phosphorus tolerance of Pueraria lobata:The activities of antioxidant enzymes（superoxide dismutase,peroxidase and catalase）increased significantly（P<0.05）under low phosphorus(0.05mmol·L^-1)treatment for three different provenances,and the content of malondialdehyde decreased,indicating that Pueraria lobata improved the activities of protective enzymes through self-regulation under low phosphorus stress,and the activities of reactive oxygen radicals and membrane lipid peroxidation were increased.The proline content of Pueraria lobata from three different provenances increased,and the soluble sugar content changed as follows:Pueraria lobata from Australia increased first and then decreased,Pueraria lobata from Jiangsu continued to increase,and Pueraria lobata from Guizhou decreased first and then increased;The changes of soluble protein content are:Pueraria lobata in Australia showed a trend of first decreasing and then increasing,and Pueraria lobata in Jiangsu and Guizhou showed a continuous upward trend.It shows that the adaptability of kudzu vine with different sources is different under phosphorus stress at different times,which shows that the adaptability of kudzu vine in Australia is stronger than that of kudzu vine in Jiangsu and Guizhou.Based on the comprehensive analysis of the phenotype and physiological and biochemical indexes of Pueraria lobata,it is found that Pueraria lobata in Australia belongs to low phosphorus tolerance and Pueraria lobata in Jiangsu belongs to low phosphorus sensitivity.Further proteomic study was made on the two species of Pueraria lobata.（3）TMT technique was used to study the protein formation of low-phosphorus tolerant kudzu vine and low-sensitivity kudzu vine under low-phosphorus stress,and the protein differentially expressed in the roots of low-phosphorus tolerant kudzu vine was determined.By controlling the difference ratio by more than 1.5 times,234differentially expressed proteins were screened from Pueraria lobata with low phosphorus tolerance under low phosphorus treatment,of which 82 were up-regulated by protein and 152 were down-regulated.GO analysis and KEGG analysis of differential proteins showed that low phosphorus stress had a significant effect on the proteins related to carbohydrate and energy metabolism of Pueraria lobata,mainly affecting the content and expression of proteins related to glycolysis/gluconeogenesis,TCA cycle and photosynthesis.In particular,glyceraldehyde-3-phosphate dehydrogenase,glutathione-S-transferase and phosphoenolpyruvate carboxylase proteins are quite different in this study,which can be used as candidate genes for gene cloning and gene function verification related to low phosphorus stress.