title: Metagenomic assessment of methane production-oxidation and nitrogen metabolism of long term manured systems in lowland rice paddy.
abstract: Biochemical pathways of methanogenesis and methanotrophy coupled with carbon (C)-nitrogen (N) metabolism were studied in long term (13years) manured systems in lowland rice paddy through metagenomics approach. Manured systems included in this study were, control (exclusion of application of any manure), farm yard manure (FYM, @5Mgha-1yr-1) and green manuring (GM with Sesbania aculeata). Metagenomic sequence data revealed the dominance of C decomposing bacterial communities' like Proteobacteria, Planctomycetes, Actinobacteria, Firmicutes, Acidobacteria, in manure amended soils as compared to control. Diversities for assimilatory and dissimilatory N-fixing microorganisms at phylum level were found higher under GM as compared to rest. Two genera responsible for methanogenesis, viz. Methanolobus and Methanotorris were absent in manured systems as compared to control. The acetoclastic and serine pathway was found as the predominant pathway for methanogenesis and methanotrophy, respectively, in tropical lowland rice paddy. Abundance reads of enzymes were in the range of 254-445 in the acetoclastic methanogenesis pathway. On the other hand, these were varied from 165 to 216 in serine pathway of methanotrophy. Lowland paddy soil exhibited higher functional and structural diversities in manured systems as compared to unamended control in respect to labile C pools and CH4production. Methane (CH4) emission was 31% higher in FYM system than GM. However, nitrous oxide (N2O) emission was found 25% higher in GM as compared to FYM. As a whole, bacterial diversities were higher under FYM system in tropical lowland rice paddy as compared to GM and unamended systems.
authors.affiliation: Division of Crop Production, ICAR-Central Research Institute for Jute and Allied Fibre, Kolkata 700120, West Bengal, India. Electronic address: pratap162001@gmail.com.
authors.forename: P
authors.initials: P
authors.lastname: Bhattacharyya
authors.affiliation: Dept. of Applied Sciences, ITM University, Vadodadra, Gujarat 391510, India.
authors.forename: K S
authors.initials: KS
authors.lastname: Roy
authors.affiliation: Division of Crop Production, ICAR-National Rice Research Institute, Odisha 753006, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Nayak
authors.affiliation: Division of Crop Production, ICAR-National Rice Research Institute, Odisha 753006, India.
authors.forename: M
authors.initials: M
authors.lastname: Shahid
authors.affiliation: Division of Crop Production, ICAR-National Rice Research Institute, Odisha 753006, India.
authors.forename: B
authors.initials: B
authors.lastname: Lal
authors.affiliation: Division of Crop Production, ICAR-National Rice Research Institute, Odisha 753006, India.
authors.forename: P
authors.initials: P
authors.lastname: Gautam
authors.affiliation: Indian Council of Agricultural Research, India.
authors.forename: T
authors.initials: T
authors.lastname: Mohapatra
keywords: C-N metabolism; Green manure; Metagenome; Methane production-oxidation; Rice-paddy