Abstract
Paenibacillus polymyxa A18 was isolated from termite gut and was identified as a potential cellulase and hemicellulase producer in our previous study. Considering that members belonging to genus Paenibacillus are mostly free-living in soil, we investigated here the essential genetic features that helped P. polymyxa A18 to survive in gut environment. Genome sequencing and analysis identified 4608 coding sequences along with several elements of horizontal gene transfer, insertion sequences, transposases and integrated phages, which add to its genetic diversity. Many genes coding for carbohydrate-active enzymes, including the enzymes responsible for woody biomass hydrolysis in termite gut, were identified in P. polymyxa A18 genome. Further, a series of proteins conferring resistance to 11 antibiotics and responsible for production of 4 antibiotics were also found to be encoded, indicating selective advantage for growth and colonization in the gut environment. To further identify genomic regions unique to this strain, a BLAST-based comparative analysis with the sequenced genomes of 47 members belonging to genus Paenibacillus was carried out. Unique regions coding for nucleic acid modifying enzymes like CRISPR/Cas and Type I Restriction-Modification enzymes were identified in P. polymyxa A18 genome suggesting the presence of defense mechanism to combat viral infections in the gut. In addition, genes responsible for the formation of biofilms, such as Type IV pili and adhesins, which might be assisting P. polymyxa A18 in colonizing the gut were also identified in its genome. In situ colonization experiment further confirmed the ability of P. polymyxa A18 to colonize the gut of termite.
Highlights
Plant biomass or lignocellulosic biomass, which is composed of cellulose, hemicellulose, lignin, and pectin, is one of the largest repositories of naturally fixed carbon
Since termite guts have a dense microbial flora actively involved in lignocellulose degradation, it has served as an excellent platform for isolation of cellulolytic organisms
Screening of cellulolytic microorganisms from the termite gut in our previous study led to the identification of a strain designated A18, which was found to be the maximum producer of cellulases amongst all the isolates[6]
Summary
Plant biomass or lignocellulosic biomass, which is composed of cellulose, hemicellulose, lignin, and pectin, is one of the largest repositories of naturally fixed carbon. Other strains of P. polymyxa like M1, SC2, CR1, Sb3-1 have been found to be cellulolytic in nature but all are present in the rhizosphere[9,10]. These species are known as plant growth promoting rhizobacterium (PGPR) and are used in agriculture and industries[11]. Various proteins participating in biofilm synthesis, like capsular polysaccharides, RTX proteins, Type IV pili, Type 6 secretion systems, and adhesins, have been found to be associated with gut colonization[16,17] These features present in gut symbionts allow the formation of mutualistic interactions with the host organism[18]. Its ability to colonize the termite gut was established by performing in situ experiment
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
