摘要
A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus （P） is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmALMT genes were identified in the soybean genome. Expression patterns diverged considerably among GmALMTs in response to phosphate （Pi） starvation in leaves, roots and flowers, with expression altered by P availability in 26 of the ：34 GmALMTs. One root-specific GmALMT whose expression was significantly enhanced by Pi-starvation, GmALMTS, was studied in more detail to determine its possible role in soybean P nutrition. Analysis of GmALMT5 tissue expression patterns, subcellular localization, and malate exudation from transgenic soybean hairy rootsoverexpressing GmALMT5, demonstrated that GmALMT5 is a plasma membrane protein that mediates malate efflux from roots. Furthermore, both growth and P content of transgenic Arabidopsis overexpressing GmALMT5 were significantly increased when sparingly soluble Ca-P was used as the external P source. Taken together, these results indicate that members of the soybean GmALMT gene family exhibit diverse responses to Pi starvation. One member of this family, GmALMT5, might contribute to soybean P efficiency by enhancing utilization of sparingly soluble P sources under P limited conditions.
A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus （P） is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmALMT genes were identified in the soybean genome. Expression patterns diverged considerably among GmALMTs in response to phosphate （Pi） starvation in leaves, roots and flowers, with expression altered by P availability in 26 of the ：34 GmALMTs. One root-specific GmALMT whose expression was significantly enhanced by Pi-starvation, GmALMTS, was studied in more detail to determine its possible role in soybean P nutrition. Analysis of GmALMT5 tissue expression patterns, subcellular localization, and malate exudation from transgenic soybean hairy rootsoverexpressing GmALMT5, demonstrated that GmALMT5 is a plasma membrane protein that mediates malate efflux from roots. Furthermore, both growth and P content of transgenic Arabidopsis overexpressing GmALMT5 were significantly increased when sparingly soluble Ca-P was used as the external P source. Taken together, these results indicate that members of the soybean GmALMT gene family exhibit diverse responses to Pi starvation. One member of this family, GmALMT5, might contribute to soybean P efficiency by enhancing utilization of sparingly soluble P sources under P limited conditions.
基金
supported by grants from the National Natural Science Foundation of China (31672220, 31422046 and U1301212)
the National Key Research and Development Program (2016YFD0100700)
the Guangdong Natural Science Funds for Distinguished Young Scholars (2015A030306034)
the Guangdong High-level Personnel of Special Support Program (2015TQ01N078 and 2015TX01N042)
the Research Team Project of the Natural Science Foundation of Guangdong Province (2016A030312009). D D F
