Amin A, Naveed M, Munawar U, Sarwar A, Latif Z. Characterization of Mercury-Resistant Rhizobacteria for Plant Growth Promotion: An In Vitro and In Silico Approach.
Curr Microbiol 2021;
78:3968-3979. [PMID:
34550433 DOI:
10.1007/s00284-021-02660-0]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
In this study, a total 30 rhizobacterial isolates were screened out based on resistance against different concentrations of mercuric chloride (HgCl2), growth on nitrogen-free mannitol (NFM) and production of indole-3-acetic acid (IAA). The biochemical and plant growth promoting characterization of selected isolates was performed by different biochemical tests. Out of 30, six isolates, UM-3, AZ-5, UM-7, UM-11, UM-26, and UM-28 showed resistance at 30 µg/ml HgCl2, pronounced growth on NFM and high production of IAA as 18.6, 16.7, 16, 18.7, 14, and 16 µg/ml, respectively (P < 0.05). The 16S rDNA ribotyping and phylogenetic analysis of selected bacterial isolates were performed and characterized as Exiguobacterium sp. UM-3 (KJ736011), Bacillus thuringiensis AZ-5 (KJ675627), Bacillus subtilis UM-7 (KJ736013), Enterobacter cloacae UM-11 (KJ736014), Pseudomonas aeruginosa UM-26 (KJ736016), P. aeruginosa UM-28 (KJ736017) and Bacillus pumilus UM-16 (KJ736015) used as negative control. B. thuringiensis AZ-5 showed high resistance against 30 µg/ml of HgCl2 due to the presence of merB gene. The structural determination of MerB protein was carried out using bioinformatics tools, i.e., Protparam, Pfam, InterProScan, STRING, Jpred4, PSIPRED, I-TASSER, COACH server and ERRAT. These tools predicted the structural based functional homology of MerB protein (organomercuric lyase) in association with MerA (mercuric reductase) in bacterial Hg-detoxification system.
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