Abstract
Two phosphate-solubilizing bacterial strains were isolated and identified as Acinetobacter calcoaceticus YC-5a and Enterobacter agglomerans KMC-7 based on the 16S rRNA gene sequence analysis. A. calcoaceticus YC-5a is less well known as a phosphate-solubilizing plant-associated bacterium. The plant growth-promoting properties of the phosphate-solubilizing bacteria (PSB) were characterized in vitro, including their phosphate-solubilizing activities and their capabilities for producing indole-3-acetic acid and siderophores. A pot experiment was conducted to elucidate the effects of inoculating both strains on the growth and Pb uptake of Brassica juncea grown in different concentrations of Pb-contaminated soils. Inoculation with both PSB not only stimulated the growth of B. juncea, but it also influenced the accumulation of Pb in the shoots and roots of the host plant. The present study demonstrates that PSB are a valuable microbial resource that can be exploited to improve the efficiency of phytoextraction.
Acknowledgements
This study was financially supported by the National High Technology Research and Development Program of China [grant number 2007AA03Z456]; the National Natural Science Foundation of China [grant numbers 20606026, 20776119, 21076169 and 31000019]; the Xi'an Research and Development Program [grant numbers NC08005, YF07078]; the Scientific Research Program of Shaanxi Provincial Department of Education, China [grant numbers 08JK452, 08JK453, JG08181, 2010JC21, 2010JS107, 2010JS108, 2010JK876 and 2010JS109]; Shaanxi Provincial Scientific Technology Research and Development Program [grant number 2007K06-03, 2010JQ2012 and SJ08B03]; the Specialized Research Fund for the Doctoral Program of Higher Education of China [grant numbers 20096101120023 and 20096101110014] and Shaanxi Key Subject Program, China.