Heavy metal resistant PGPR mediated bioremediation, phytostimulation and stress alleviation is an eco-friendly method for sustainable agriculture in the metal contaminated soil. The isolation of such PGPR is highly demanding to reduce heavy metals in contaminated cultivated fields for agricultural benefit. The present study was successful to isolate a potent multi-heavy metal resistant PGPR strain, identified as Enterobacter aerogenes strain K6 based on MALDI-TOF MS, FAME analysis and 16S rDNA sequence homology, from rice rhizosphere contaminated with a variety of heavy metals/metalloid near industrial area. The strain exhibited high degree of resistance to Cd²⁺, Pb²⁺ and As³⁺ upto 4000 µg/mL, 3800 µg/mL and 1500 µg/mL respectively. Intracellular Cd accumulation of this strain was evidenced by AAS-SEM-TEM-EDX-XRF studies. Moreover, it showed several important PGP traits like IAA production, nitrogen fixation, phosphate solubilization, ACC deaminase activity even under high Cd stress (upto 3000 µg/mL). The combined effect of Cd resistance and PGP activities of this strain was manifested to the significant (p < 0.05) growth promotion of rice seedling under Cd stress by reducing oxidative stress (through antioxidants), stress ethylene and Cd uptake in seedlings. Thus K6 strain conferred Cd-tolerance in rice seedlings and could be applied as PGPR in contaminated fields.

抗重金属的PGPR介导的生物修复，植物刺激和缓解压力是一种在金属污染土壤中实现可持续农业的生态友好方法。为了保护农业利益，对这类PGPR的隔离要求极高，以减少受污染的耕地中的重金属。本研究成功地从受多种重金属/准金属污染的水稻根际中分离出了有效的抗重金属的PGPR菌株，根据MALDI-TOF MS，FAME分析和16S rDNA序列同源性鉴定为产气肠杆菌K6菌株。工业区附近。该菌株对Cd 2 ⁺，Pb ²⁺和As ³⁺表现出高度的抗性分别高达4000 µg / mL，3800 µg / mL和1500 µg / mL。通过AAS-SEM-TEM-EDX-XRF研究证明了该菌株的细胞内Cd蓄积。而且，即使在高Cd胁迫下（高达3000 µg / mL），它也表现出一些重要的PGP特性，例如IAA产生，固氮，磷酸盐增溶，ACC脱氨酶活性。通过降低幼苗的氧化胁迫（通过抗氧化剂），胁迫乙烯和镉吸收，可证明该菌株对Cd抗性和PGP活性的联合作用显着（p <0.05）促进了Cd胁迫下水稻幼苗的生长。因此，K6菌株在水稻幼苗中具有耐Cd的特性，可作为PGPR在受污染的田地中使用。