Impact assessment of pesticides on soil health through conventional and metagenomic approaches and their biodegradation using indigenous microbes
| dc.contributor.advisor | Sharma, Anita | |
| dc.contributor.author | Gangola, Saurabh | |
| dc.date.accessioned | 2019-02-21T10:07:11Z | |
| dc.date.available | 2019-02-21T10:07:11Z | |
| dc.date.issued | 2018-08 | |
| dc.description.abstract | Application of agro-pesticide technologies, hybrid seeds and systematic irrigation in agriculture practices has contributed significantly in enhanced food production and achieving green revolution. On the other hand injudicious use of synthetic chemicals has developed environmental pollution which is posing serious health problem in human beings. In this study attempt has been made to reduce pesticide pollution with the help of isolated indigenous bacteria. To isolate pesticide degrading bacteria, pesticide contaminated soil samples were collected from the agricultural fields of Gularbhoj, Bhatbhoj and Dineshpur, Uttarakhand. Out of 12 bacterial isolates recovered from the contaminated soil, only four isolates (1B, 1D, 2D and 3C) were selected for bidegradation studies. Bacterial isolates tolerated up to 450 ppm pesticide(s) and utilized cypermethrin, imidacloprid, fipronil and sulfosulfuron as C source in minimal medium and showed maximum degradation of cypermethrin (95%). Consortium of four bacterial isolates degraded cypermethrin (99%), imidacloprid (99%), fipronil(95%) and sulfosulfuron(93%) in 15 days as compared to control (7%). Molecular characterization of 1B, 1D, 2D and 3C showed 99-100% homology with Bacillus brevis (MG948470), Bacillus subtillis (MG948470), Bacillus cereus (MH341691) and Bacillus sp. (MH341692) respectively. Individual bacterial isolate(s) and their consortium showed maximum degradation of imidacloprid (99%) after 15 days as compared to control (7%) in soil slurry. Common metabolites of cypermethrin biodegradation by 1D were Phenol, 3-(2,2-dichloroethenyl) 2,2-dimethyl cyclopropane carboxylate, chloroacetic acid, 1-decanol, cyclododecylamine, cyclopentane, palmitoleic acid, decanoic acid and undecyl ester. Based on GC-MS analysis of biodegraded products of cypermethrin by 1D, a new pathway is proposed. Under stress conditions production of enzymes under stress was higher than control. Km values of the enzymes were low in stress. Amplification of esterase (EST) gene from 1B, 1D, ALDH gene from 1B, 3C and laccase gene from 1D, 2D and 3C was observed. Proteomic analysis of ID and 2D isolates showed increase in stressed response proteins and catabolic/pesticide degrading proteins as compared to control. Metagenomic study of 2 soil samples by DGGE revealed that number of bands were high in unspiked but contaminated soil as compared to pesticide spiked contaminated soil. Maximum copy number of 16S rDNA was observed in Dineshpur soil (pesticide contaminated soil) followed by Gularbhoj (control and pesticide contaminated soil) and Dineshpur (Control) in qRTPCR study. Metagenomic analysis of the pesticide contaminated (Dineshpur 1D, Gularbhoj 2G) and uncontaminated soil samples (Dineshpur1DC and Gularbhoj 2GC) revealed that total reads for 1D (893,487) were high as compared to 1DC (99,265). Total reads for 2G (562,416) were low as compared to 2GC (873,083) soil sample. Results of metagenomic study showed the presence of Proteobacteria (Kaistobacter, Serratia,), Firmicutes (Clostridium, Bacillus), and Actinobacteria (Nocardioides,Arthrobacter) Dineshpur (ID). Gularbhoj (2G) soil showed the presence of Firmicutes (Clostridium), Actinobacteria (Nocardioides) and Chloroflexi (Bellilinea, Anaerolinea, Caldilinea). Repeated application of the pesticides in the agriculture fields forces to adopt new microbial population with simultaneous replacement of the older one. Present study recommends the application of indigenous microorganisms in biodegradation of common agriculture pesticides. Study on metabolomics and proteomics gives significant insight of three major genes responsible for biodegradation of pesticides. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810096352 | |
| dc.keywords | pesticides, soil health, biodegradation, microbes | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 219 | en_US |
| dc.publisher | G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand) | en_US |
| dc.research.problem | Pesticides | en_US |
| dc.sub | Microbiology | en_US |
| dc.subject | null | en_US |
| dc.theme | Soil Health | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Impact assessment of pesticides on soil health through conventional and metagenomic approaches and their biodegradation using indigenous microbes | en_US |
| dc.type | Thesis | en_US |