Application of heavy metal resistant plant growth promoting rhizobacteria has an important role as they help to evade metal-induced toxicity in plants on one hand and enhance plant growth on the other. The present study is therefore focused on the characterization of a cadmium resistant bacterial strain isolated from heavy metal contaminated rhizospheric soil designated as S8. This S8 strain was selected in terms of cadmium resistance and plant growth promoting traits. Moreover, it also showed resistance to lead and arsenic to a considerable extent. The selected strain S8 was identified as Klebsiella michiganensis by modern approaches of bacterial taxonomy. The plant growth promoting traits exhibited by the strain include 1-aminocyclopropane-1-carboxylic acid deaminase activity (58.33 ng α-keto butyrate/mg protein/h), Indole-3-acetic acid production (671 μg/ml), phosphate solubilization (71.98 ppm), nitrogen fixation (3.72 μg of nitrogen fixed/h/mg protein) etc. Besides, the strain also exhibited high cadmium removal efficiency (73–97%) from the medium and intracellular accumulation as well. Its efficiency to alleviate cadmium-induced toxicity was determined against a rice cultivar in terms of morphological and biochemical changes. Enhanced growth and reduced oxidative stress were detected in presence of the bacterium. On the basis of these results, it can be concluded that K. michiganensis strain S8 is cadmium accumulating plant growth promoting rhizobacterium that can be applied in cadmium contaminated agricultural soil to achieve better productivity of rice.

抗重金属植物生长促进根瘤菌的应用具有重要作用，因为它们一方面有助于避免金属诱导的植物毒性，另一方面可以帮助植物生长。因此，本研究着重于从重金属污染的根际土壤中命名为S8的抗镉细菌菌株的表征。根据对镉的抗性和促进植物生长的性状选择了该S8菌株。而且，它还显示出对铅和砷的相当大的抵抗力。选定的菌株S8被鉴定为密歇根氏克雷伯菌通过现代的细菌分类学方法。该菌株表现出的促进植物生长的特性包括1-氨基环丙烷-1-羧酸脱氨酶活性（58.33 ngα-酮丁酸/ mg蛋白质/ h），吲哚-3-乙酸的产生（671μg/ ml），磷酸盐增溶。 （71.98 ppm），固氮（3.72μg固氮/ h / mg蛋白）等。此外，该菌株还显示出从培养基和细胞内积累的高镉去除效率（73-97％）。根据形态和生化变化，确定了其减轻镉诱导的毒性对水稻品种的效率。在细菌的存在下检测到生长增强和氧化应激降低。根据这些结果，可以得出结论：密歇根K. S8菌株是促进植物生长的镉积累根瘤菌，可应用于受镉污染的农业土壤中，以提高水稻的生产力。