Affiliation:
1. College of Grassland Agriculture Northwest A&F University Yangling Shaanxi 712100 People's Republic of China
2. College of Horticulture Northwest A&F University Yangling Shaanxi 712100 People's Republic of China
3. Institute for Agricultural Biosciences Oklahoma State University 3210 Sam Noble Parkway Ardmore Oklahoma 73401 USA
4. Department of Plant and Microbial Biology University of California Berkeley California 94720 USA
Abstract
SUMMARYAlthough vacuolar phosphate transporters (VPTs) are essential for plant phosphorus adaptation, their role in Rhizobium–legume symbiosis is unclear. In this study, homologous genes of VPT1 (MtVPTs) were identified in Medicago truncatula to assess their roles in Rhizobium–legume symbiosis and phosphorus adaptation. MtVPT2 and MtVPT3 mainly positively responded to low and high phosphate, respectively. However, both mtvpt2 and mtvpt3 mutants displayed shoot phenotypes with high phosphate sensitivity and low phosphate tolerance. The root‐to‐shoot phosphate transfer efficiency was significantly enhanced in mtvpt3 but weakened in mtvpt2, accompanied by lower and higher root cytosolic inorganic phosphate (Pi) concentration, respectively. Low phosphate induced MtVPT2 and MtVPT3 expressions in nodules. MtVPT2 and MtVPT3 mutations markedly reduced the nodule number and nitrogenase activity under different phosphate conditions. Cytosolic Pi concentration in nodules was significantly lower in mtvpt2 and mtvpt3 than in the wildtype, especially in tissues near the base of nodules, probably due to inhibition of long‐distance Pi transport and cytosolic Pi supply. Also, mtvpt2 and mtvpt3 could not maintain a stable cytosolic Pi level in the nodule fixation zone as the wildtype under low phosphate stress. These findings show that MtVPT2 and MtVPT3 modulate phosphorus adaptation and rhizobia–legume symbiosis, possibly by regulating long‐distance Pi transport.
Funder
National Natural Science Foundation of China
Subject
Cell Biology,Plant Science,Genetics
Cited by
1 articles.
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