Isolation and screening of pesticide-tolerant phosphate-solublizing bacteria from potato rhizosphere

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dc.contributor.advisorVyas, Pratibha
dc.contributor.authorManpreet Kaur
dc.date.accessioned2021-07-30T04:37:27Z
dc.date.available2021-07-30T04:37:27Z
dc.date.issued2021
dc.description.abstractThe present study was carried out with the aim to develop pesticide-tolerant phosphatesolubilizing bacterial inoculants for improving the growth and phosphorus uptake in potato. A total of 37 phosphate-solubilizing bacteria were isolated from the rhizosphere of potato growing at different locations of Punjab and Himachal Pradesh. The bacterial isolates showed phosphate solubilization index ranging from 1.3 to 6.7 mm on modified Pikovskaya agar and phosphate solubilization in liquid medium varying from 115.4 – 919 µg ml-1 with significant difference among the isolates. The isolates were further tested for their tolerance against two commonly used pesticides in potato on minimal salt agar medium amended with three concentrations 1.25, 2.5 and 7.5 μl ml-1 (lower, recommended and higher dosages) of chlorpyrifos and 0.187, 0.375 and 0.75 g ml-1 (lower, recommended and higher dosages) of carbofuran. Out of 37 PSB isolates, only 7 showed pesticide tolerance. The phosphate solubilising ability of the isolates was found to decrease significantly with increased concentrations of pesticides. Seven pesticide-tolerant PSB were identified as Arthrobacter oxydans (PR2PSB2), Bacillus licheniformis (PR3PSB9, PR3PSB10, PR3PSB12 and PR3PSB13), Bacillus subtilis (PR3PSB11) and Bacillus flexus (PR4PSB1) based on phenotypic features, biochemical tests and Matrix-Assisted Laser Desorption/Ionization time of Flight Mass Spectroscopy (MALDI-TOF-MS) analysis. Four pesticide-tolerant and phosphate-solubilizing bacterial isolates belonging to different species were tested for their ability to promote growth and phosphorus uptake in potato in pesticide amended soils under greenhouse conditions in pots. A significant difference was observed in the growth parameters, P content in shoots and soil P with the use of pesticide-tolerant PSB strains over the uninoculated control. The plant growth promotion and phosphorus content decreased with an increase in pesticide concentrations. The bacterial strains also differed significantly in their ability to promote the potato growth and phosphorus uptake. The highest growth promotion and P uptake was observed with consortium 1 containing Bacillus licheniformis, Bacillus flexus and Bacillus subtilis (PR3PSB10, PR4PSB1 and PR3PSB11). The study has led to the selection of pesticidetolerant phosphate-solubilizing bacterial consortium for improved growth and phosphorus uptake in potato.en_US
dc.identifier.citationManpreet Kaur (2021). Isolation and screening of pesticide-tolerant phosphate-solublizing bacteria from potato rhizosphere (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.en_US
dc.identifier.urihttps://krishikosh.egranth.ac.in/handle/1/5810171117
dc.keywordsCarbofuran, chlorpyrifos, growth promotion, pesticide tolerance, phosphate solubilization, potatoen_US
dc.language.isoEnglishen_US
dc.pages64en_US
dc.publisherPunjab Agricultural University, Ludhianaen_US
dc.research.problemIsolation and screening of pesticide-tolerant phosphate-solublizing bacteria from potato rhizosphereen_US
dc.subMicrobiologyen_US
dc.themeIsolation and screening of pesticide-tolerant phosphate-solublizing bacteria from potato rhizosphereen_US
dc.these.typeM.Scen_US
dc.titleIsolation and screening of pesticide-tolerant phosphate-solublizing bacteria from potato rhizosphereen_US
dc.typeThesisen_US
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