TY - JOUR
T1 - Influence of nitrogen and phosphorus on polyphosphate accumulation in Gigaspora margarita during spore germination
AU - Yao, Qing
AU - Ohtomo, Ryo
AU - Saito, Masanori
N1 - Funding Information:
Acknowledgments We thank Drs. Katsuharu Saito and Tomoko Kojima for their helpful suggestions during the experiments. This work was supported by the Japan Society for the Promotion of Science (JSPS, P03518) and the Natural Science Fund of China (NSFC, 30570060).
PY - 2010/5
Y1 - 2010/5
N2 - Polyphosphate (polyP) is the form in which phosphorus (P) is transferred from extraradical hyphae into arbuscles in the symbiotic stage of arbuscular mycorrhizal fungi. However, polyP dynamics in the presymbiotic stage are less understood. In this study, we aimed to investigate polyP accumulation in Gigaspora margarita as influenced by nitrogen (N) and/or P supply during germination. Spores of G. margarita were incubated on medium with or without P or N addition. PolyP content in the fungal tissue was monitored using a polyP kinase/luciferase system, and polyP synthetic activity was determined with 32P labeling. The results showed that both N and P were necessary for polyP accumulation in germ tubes. Nitrate increased the polyP content in germ tubes, but ammonium did not. Along with germination, polyP content decreased in spores, but increased in germ tubes. 32P labeling indicated that polyP synthetic activity increased in germ tubes along with germination, but was negligible in spores. Our results suggest that, in the presymbiotic stage of G. margarita, uptake of environmental N and P increases polyP content in germ tubes, and that polyP synthesis occurs mainly therein, leading to polyP accumulation. The possible mechanism of transfer of polyP from spores to hyphae remains to be elucidated.
AB - Polyphosphate (polyP) is the form in which phosphorus (P) is transferred from extraradical hyphae into arbuscles in the symbiotic stage of arbuscular mycorrhizal fungi. However, polyP dynamics in the presymbiotic stage are less understood. In this study, we aimed to investigate polyP accumulation in Gigaspora margarita as influenced by nitrogen (N) and/or P supply during germination. Spores of G. margarita were incubated on medium with or without P or N addition. PolyP content in the fungal tissue was monitored using a polyP kinase/luciferase system, and polyP synthetic activity was determined with 32P labeling. The results showed that both N and P were necessary for polyP accumulation in germ tubes. Nitrate increased the polyP content in germ tubes, but ammonium did not. Along with germination, polyP content decreased in spores, but increased in germ tubes. 32P labeling indicated that polyP synthetic activity increased in germ tubes along with germination, but was negligible in spores. Our results suggest that, in the presymbiotic stage of G. margarita, uptake of environmental N and P increases polyP content in germ tubes, and that polyP synthesis occurs mainly therein, leading to polyP accumulation. The possible mechanism of transfer of polyP from spores to hyphae remains to be elucidated.
KW - Arbuscular mycorrhizal fungi
KW - Nitrogen sources
KW - Phosphorus
KW - Polyphosphate accumulation
KW - Presymbiotic stage
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U2 - 10.1007/s11104-009-0201-0
DO - 10.1007/s11104-009-0201-0
M3 - Article
AN - SCOPUS:77950340657
VL - 330
SP - 303
EP - 311
JO - Plant and Soil
JF - Plant and Soil
SN - 0032-079X
IS - 1
ER -