• Title/Summary/Keyword: microbial genomics

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Diversity and Polymorphism in AHL-Lactonase Gene (aiiA) of Bacillus

  • Huma, Nusrat;Shankar, Pratap;Kushwah, Jyoti;Bhushan, Ashish;Joshi, Jayadev;Mukherjee, Tanmoy;Raju, Sajan C.;Purohit, Hemant J.;Kalia, Vipin Chandra
    • Journal of Microbiology and Biotechnology
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    • v.21 no.10
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    • pp.1001-1011
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    • 2011

  • To explore bacterial diversity for elucidating genetic variability in acylhomoserine lactone (AHL) lactonase structure, we screened 800 bacterial strains. It revealed the presence of a quorum quenching (QQ) AHL-lactonase gene (aiiA) in 42 strains. These 42 strains were identified using rrs (16S rDNA) sequencing as Bacillus strains, predominantly B. cereus. An in silico restriction endonuclease (RE) digestion of 22 AHL lactonase gene (aiiA) sequences (from NCBI database) belonging to 9 different genera, along with 42 aiiA gene sequences from different Bacillus spp. (isolated here) with 14 type II REs, revealed distinct patterns of fragments (nucleotide length and order) with four REs; AluI, DpnII, RsaI, and Tru9I. Our study reflects on the biodiversity of aiiA among Bacillus species. Bacillus sp. strain MBG11 with polymorphism (115Alanine > Valine) may confer increased stability to AHL lactonase, and can be a potential candidate for heterologous expression and mass production. Microbes with ability to produce AHL-lactonases degrade quorum sensing signals such as AHL by opening of the lactone ring. The naturally occurring diversity of QQ molecules provides opportunities to use them for preventing bacterial infections, spoilage of food, and bioremediation.

  • https://doi.org/10.4014/jmb.1105.05056 인용 PDF KSCI

Genome Snapshot of Paenibacillus polymyxa ATCC $842^T$

  • Jeong, Hae-Young;Kim, Ji-Hyun;Park, Yon-Kyoung;Kim, Seong-Bin;Kim, Chang-Hoon;Park, Seung-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.16 no.10
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    • pp.1650-1655
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    • 2006

  • Bacteria belonging to the genus Paenibacillus are facultatively anaerobic endospore formers and are attracting growing ecological and agricultural interest, yet their genome information is very limited. The present study surveyed the genomic features of P. polymyxa ATCC $842^T$ using pulse-field gel electrophoresis of restriction fragments and sample genome sequencing of 1,747 reads (approximately 17.5% coverage of the genome). Putative functions were assigned to more than 60% of the sequences. Functional classification of the sequences showed a similar pattern to that of B. subtilis. Sequence analysis suggests nitrogen fixation and antibiotic production by P. polymyxa ATCC $842^T$, which may explain its plant growth-promoting effects.

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Two Bacterial Entophytes Eliciting Both Plant Growth Promotion and Plant Defense on Pepper (Capsicum annuum L.)

  • Kang, Seung-Hoon;Cho, Hyun-Soo;Cheong, Hoon;Ryu Choong-Min;Kim, Ji-Hyun;Park, Seung-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.17 no.1
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    • pp.96-103
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    • 2007

  • Plant growth-promoting rhizobacteria (PGPR) have the potential to be used as microbial inoculants to reduce disease incidence and severity and to increase crop yield. Some of the PGPR have been reported to be able to enter plant tissues and establish endophytic populations. Here, we demonstrated an approach to screen bacterial endophytes that have the capacity to promote the growth of pepper seedlings and protect pepper plants against a bacterial pathogen. Initially, out of 150 bacterial isolates collected from healthy stems of peppers cultivated in the Chungcheong and Gyeongsang provinces of Korea, 23 putative endophytic isolates that were considered to be predominating and representative of each pepper sample were selected. By phenotypic characterization and partial 16S rDNA sequence analysis, the isolates were identified as species of Ochrobacterium, Pantoea, Pseudomonas, Sphingomonas, Janthinobacterium, Ralstonia, Arthrobacter, Clavibacter, Sporosarcina, Acidovorax, and Brevundimonas. Among them, two isolates, PS4 and PS27, were selected because they showed consistent colonizing capacity in pepper stems at the levels of $10^6-10^7CFU/g$ tissue, and were found to be most closely related to Pseudomonas rhodesiae and Pantoea ananatis, respectively, by additional analyses of their entire 16S rDNA sequences. Drenching application of the two strains on the pepper seedlings promoted significant growth of peppers, enhancing their root fresh weight by 73.9% and 41.5%, respectively. The two strains also elicited induced systemic resistance of plants against Xanthomonas axonopodis pv. vesicatoria.

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