Study On The Difference Of Phosphorus-zinc Interaction Effect And Mechanism In Different Rice Varieties

Rice is one of the three major food crops in the world and the main food crop in China.Phosphorus and Zinc play an important role in the normal growth and development of rice.Phosphorus is an important component of a variety of organic compounds in rice.Zinc is a structural cofactor of important proteins and more than 300 enzymes,and it plays an important role in biological metabolism,biological membrane stability and gene expression regulation.Although the P-Zn interaction is recognized in recent years,the physiological and molecular mechanism is still unclear.In this study,Guangliangyou 35,Taichung 65,Jarjan and Anjana Dhan,osnla1-2 mutants and Os PHR2-OE transgenic plants were used as research materials to analyze the growth phenotype,phosphorus and zinc content,related gene expression levels,acid phosphatase activity and SOD activity in rice under the condition of phosphorus and zinc interaction.The genotypic differences,physiological and molecular mechanisms of phosphorus and zinc interaction in rice were also analyzed.Under the condition of low phosphorus,the total root length of Guangliangyou 35,average root diameter of Jarjan,root-to-shoot translocation of P of Taichung 65,and distribution rate of P in new leaves of different rice varieties were significantly reduced by zinc addition.Under normal P condition,the root length of Taichung 65 and Anjana Dhan,the P concentration in the root of Nipponbare and Taichung 65,the phosphorus accumulation in the middle and old leaves of Guangliangyou 35,the root uptake ability of P of Nipponbare,Taichung 65 and Jarjan,root-to-shoot translocation of P of Guangliangyou 35 and Jarjan,and the distribution rate of P in the new leaves of Nipponbare,Taichung 65 and Jarjan were significantly reduced.Under the condition of zinc deficiency,phosphorus treatment significantly reduced the zinc concentration in root of Taichung 65 and Anjana Dhan,the zinc concentration in new leaves of Taichung 65 and Anjana Dhan,the root uptake ability of Zn of Taichung 65 and Anjana Dhan,and the distribution of Zn in Guangliangyou 35,Nipponbare and Anjana Dhan.Under normal zinc condition,the zinc concentration in root of Guangliangyou 35,Taichung 65 and Anjana Dhan,zinc concentration in new leaves and middle leaves of all rice varieties,zinc accumulation of Guangliangyou 35,Nipponbare,Jarjan and Anjana Dhan,the root uptake ability of zinc in Guangliangyou 35 and Jarjan,and the distribution of zinc in new leaves of all rice varieties were significantly reduced.Under the condition of low phosphorus,zinc treatment significantly increased both root and shoot dry weight of Guangliangyou 35,but significantly reduced the inorganic phosphorus concentration in basal node and other leaves.Under normal P condition,zinc treatment significantly reduced the inorganic phosphorus concentration in the root of Guangliangyou 35 and Nipponbare,but significantly increased the expression levels of P transporter genes Os PT2 and Os PT8,and the expression levels of P uptake regulated genes Os IPS1 and Os SPX1 in root of Guangliangyou 35,indicating that zinc treatment reduced the phosphorus content in roots and induced the expression of P transporter genes in Guangliangyou 35 and P uptake regulated genes in Nipponbare.Zinc treatment significantly increased the activity of acid phosphatase of root-secreted in Guangliangyou 35 and Nipponbare,indicating that the concentration of phosphorus in root decreased after zinc treatment,which induced root secreted more acid phosphatase,and increased the activity of acid phosphatase in root-secreted.Under the condition of zinc deficiency,the expression levels of Zn transporter genes Os ZIP4,Os ZIP7,Os ZIP10 and Os ZIP 11 in shoot of Guangliangyou 35 and Nipponbare were significantly reduced,and the expression levels of Zn transporter genes Os ZIP4,Os ZIP6,Os ZIP7,Os ZIP8,Os ZIP10 in root of Guangliangyou 35 and Nipponbare were significantly reduced,and the activity of superoxide dismutase(SOD)in root of Nipponbare was significantly decreased.The expression levels of Os ZIP6,Os ZIP7 and Os ZIP11 were significantly decreased by phosphorus treatment under normal zinc condition.Under low phosphorus condition,zinc treatment significantly reduced the expression levels of Os PT8 and Os SPX1 in shoot of wild type,and increased the expression level of Os SPX1 in shoot of osnla1-2 and Os PHR2-OE.Under normal phosphorus condition,the inorganic phosphorus concentration in wild-type root was significantly reduced by zinc treatment,and the expression level of Os PAP10 related to organic phosphorus hydrolysis was up-regulated.The activity of acid phosphatase of root-secreted in osnla1-2 was increased by adding zinc.Under zinc deficiency,phosphorus treatment significantly reduced the expression levels of Os ZIP8,Os ZIP9,Os ZIP10 in shoot of osnla1-2,Os PHR2-OE and wild-type,significantly increased the expression levels of Os ZIP4,Os ZIP8,Os ZIP10 in osnla1-2 and Os PHR2-OE,and Os ZIP4,Os ZIP8,Os ZIP10 in wild-type root,and decreased the activity of SOD in root of Os PHR2-OE and wild-type.In rice,the interaction between P and Zn was antagonistic.The supply of Zn inhibited the distribution of P in new leaves and the transport of P.The supply of phosphorus inhibited the ability of root system to absorb zinc.But there are some differences among different genotypes.At the same time,the molecular mechanism also showed antagonistic effect.Zinc treatment increased the expression level of related genes induced by phosphorus deficiency in roots of Guangliangyou 35 and Nipponbare,and phosphorus treatment increased the expression level of zinc transport genes in roots of Guangliangyou 35 and Nipponbare.