Chun Quan Zhu1,2,3, Xiao Fang Zhu1, Chao Wang1, Xiao Ying Dong1, Ren Fang Shen4,5. 1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China. 2. University of Chinese Academy of Sciences, Beijing, 100049, China. 3. National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China. 4. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China. rfshen@issas.ac.cn. 5. University of Chinese Academy of Sciences, Beijing, 100049, China. rfshen@issas.ac.cn.
Abstract
MAIN CONCLUSION: NO3- not only inhibited the reutilization of cell wall P via decreasing root cell wall pectin content and PME activity, but also hampered the P translocation from root to shoot. The rice cultivars 'Kasalath' (Kas) and 'Nipponbare' (Nip) were used to demonstrate that the nitrogen source NO3- inhibits internal phosphorus (P) reutilization in rice under P-absence conditions. Analysis using Kas showed that the expression of - P-induced marker genes OsIPS1/2 and OsSPX1/2/3/5 are significantly higher under 1 mM NO 3- - P (1N - P) treatment than 0 mM NO 3- - P (0N - P) treatment. The absence of NO3- from the nutrient solution significantly increased cell wall P release by increasing pectin synthesis and increasing the activity of pectin methylesterase (PME), and also significantly improved the translocation of soluble P from the root to the shoot by increasing xylem sap P content under P-absence conditions. The rice seedlings grown in 0 mM NO3- accumulated significantly higher nitric oxide (NO) in the roots than those grown in 1 mM NO3-. Exogenously applying the NO donor sodium nitroprusside (SNP) revealed that NO is a major contributor to differential cell wall P remobilization in rice by mediating pectin synthesis and demethylation under different NO3- concentrations (0 and 1 mM) under P-deprived conditions.
MAIN CONCLUSION: NO3- not only inhibited the reutilization of cell wall P via decreasing root cell wall pectin content and PME activity, but also hampered the P translocation from root to shoot. The rice cultivars 'Kasalath' (Kas) and 'Nipponbare' (Nip) were used to demonstrate that the nitrogen source NO3- inhibits internal phosphorus (P) reutilization in rice under P-absence conditions. Analysis using Kas showed that the expression of - P-induced marker genes OsIPS1/2 and OsSPX1/2/3/5 are significantly higher under 1 mM NO 3- - P (1N - P) treatment than 0 mM NO 3- - P (0N - P) treatment. The absence of NO3- from the nutrient solution significantly increased cell wall P release by increasing pectin synthesis and increasing the activity of pectin methylesterase (PME), and also significantly improved the translocation of soluble P from the root to the shoot by increasing xylem sap P content under P-absence conditions. The rice seedlings grown in 0 mM NO3- accumulated significantly higher nitric oxide (NO) in the roots than those grown in 1 mM NO3-. Exogenously applying the NO donor sodium nitroprusside (SNP) revealed that NO is a major contributor to differential cell wall P remobilization in rice by mediating pectin synthesis and demethylation under different NO3- concentrations (0 and 1 mM) under P-deprived conditions.