title: Taxonomic and functional diversity of the culturable microbiomes of epigeic earthworms and their prospects in agriculture.
abstract: Eisenia foetida and Perionyx excavatus are potent vermicomposting earthworms having immense importance in organic matter recycling under tropical conditions, particularly in India. Comparative assessment of the cultivable gut microbiome of these two epigeic earthworms after growth on lignocellulosic biomass, revealed populations of 3.2-8.3 × 10(9) CFU. Diversity analyses using 16S rDNA sequences revealed that the major dominating classes were Firmicutes (50-60%), followed by Actinobacteria (26.7-33%), and Alphaproteobacteria (5.6-6.7%). Despite exhibiting similar diversity indices and species richness, Betaproteobacteria (6.7%) and Gammaproteobacteria (11.1%) were solely present in E. foetida and P. excavatus, respectively. A set of 33 distinct morphotypes, including 18 from E. foetida and 15 from P. excavatus were selected. Carbohydrate utilization profiles generated using Hi-Carbo™ kits revealed that the isolates from the gut of P. excavatus - Arthrobacter pascens IARI-L13 and Bacillus subtilis IARIC were able to utilize 54 and 51.4% of the carbohydrates tested. Sorbose was not utilized, while unusual carbohydrates - adonitol and methyl-d-mannoside were utilized only by members from the gut of P. excavatus, while melizitose was utilized by those uniquely by E. foetida microbiome. Functional characterization revealed that β-glucosidase activity was most prevalent in the culturable microbial community. Alkaline and acid phosphatase activity was more widespread in the E. foetida gut microbiome. All the culturable gut bacterial isolates produced ammonia, but IAA was detected only in five cultures. The unique functional attributes of the two culturable microbiomes, grown on a similar diet, reveals the significance of proper selection of earthworm substrate combinations for effective vermicomposting.
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.|ICAR - National Bureau of Agriculturally Important Microorganisms, Kushmaur, Mau Nath Bhanjan, Uttar Pradesh, India.
authors.forename: Arjun
authors.initials: A
authors.lastname: Singh
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Rameshwar
authors.initials: R
authors.lastname: Tiwari
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Anamika
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Anurup
authors.initials: A
authors.lastname: Adak
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Surender
authors.initials: S
authors.lastname: Singh
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Radha
authors.initials: R
authors.lastname: Prasanna
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Saxena
authors.affiliation: Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India. latarajat@yahoo.co.in.
authors.forename: Lata
authors.initials: L
authors.lastname: Nain
authors.affiliation: ICAR - Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India.
authors.forename: Ran Vir
authors.initials: RV
authors.lastname: Singh
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D039903:Actinobacteria / Q000378:metabolism*; D000383:Agriculture; D000469:Alkaline Phosphatase / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D050260:Carbohydrate Metabolism; D000068536:Bacillota / Q000378:metabolism*; D000069196:Gastrointestinal Microbiome; D007210:Indoleacetic Acids / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D009835:Oligochaeta / Q000382:microbiology*; D020560:Proteobacteria / Q000378:metabolism*; D012988:Soil Microbiology; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; C036909:lignocellulose; D000641:Ammonia; D008031:Lignin; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D001617:beta-Glucosidase
keywords: Eisenia foetida; Hydrolytic enzymes; Metabolic profiling; Perionyx excavatus