The plant-growth-promoting actinobacteria of the genus Nocardia induces root nodule formation in Casuarina glauca

The threat of arsenic (As) pollution has become serious and leading to opt of low-cost microbial remediation strategies.Some bacteria have the ability to resist As. A group of rhizosphere bacteria have the ability to absorb arsenic. So these bacteria may be a good candidate for arsenic bioremediation from contaminated environment. Our present study of identifying suitable rhizobacterial strains led to the isolation of As-tolerant strains from arsenic pollutedrhizospheric soils of lentil in West Bengal, India.The isolated rhizobacterial strain LAR-7 had a high MIC (minimum inhibitory concentration) towards arsenate (260 mM) and arsenite (27.5 mM) and transformed 39% of arenite to arsenate under laboratory condition. Further, the strain LAR-7 had enormous plant growth-promoting characteristics (PGP), as categorized by efficient ability to solubilize phosphate, siderophore production, production of indole acetic acid-like molecules, ACC deaminase production, and nodule formation under As stressed condition. Based on 16S rRNA homology the LAR-7 was identified as Rhizobium leguminosarum andemerged as the most potent strain for As decontamination and plant growth promoter under the stress environment of As.

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Investigation of Arsenic-Resistant, Arsenite-Oxidizing Bacteria for Plant Growth Promoting Traits Isolated From Arsenic Contaminated Soils

10.21203/rs.3.rs-196992/v1 ◽

2021 ◽

Author(s):

Aritri Laha ◽

Somnath Bhattacharyya ◽

Sudip Sengupta ◽

Kallol Bhattacharyya ◽

Sanjoy GuhaRoy

Keyword(s):

Plant Growth ◽

Contaminated Soils ◽

Burkholderia Cepacia ◽

Growth Promotion ◽

Burkholderia Cenocepacia ◽

Nodule Formation ◽

Stressed Condition ◽

Bacterial Strains ◽

Plant Growth Promoting ◽

Growth Promoting

Abstract The menace of arsenic (As) pollution being severe warrants opting for low cost microbial remediation strategies. The present study of identifying suitable bacterial strains led to isolation of eleven As-tolerant strains from the As contaminated rhizosphere soils of West Bengal, India. They were found to oxidize/reduce 55%-31.6% of 5 mM As(III) and 73%-37.6% of 5 mM As(V) within 12 hrs. The four isolates (BcAl-1, JN 73, LAR-2 and AR-30) had high level of As(III) oxidase activity along with higher level of As(V) and As(III) resistance. The presence of aoxB gene was observed in these four As(III) oxidizing isolates. Evaluation of plant growth promoting characteristics revealed that BcAl-1 (Burkholderia cepacia), JN73 (Burkholderia metallica), AR-30 (Burkholderia cenocepacia) and LAR-2 (Burkholderia sp) had enormous plant growth-promoting characteristics (PGP), including ability to solubilize phosphate, siderophore production, indole acetic acid like molecules production, ACC deaminase production and nodule formation under As stressed condition. BcAl-1 and JN73 emerged as the most promising traits in As removal as well as plant growth promotion.

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