Understanding interactions between osmotolerant rhizobacteria and mustard under water deficit stress conditions
| dc.contributor.advisor | Sangeeta Paul | |
| dc.contributor.author | ARAMBAM ASHA DEVI | |
| dc.date.accessioned | 2021-09-13T05:24:04Z | |
| dc.date.available | 2021-09-13T05:24:04Z | |
| dc.date.issued | 2020 | |
| dc.description | T-10472 | en_US |
| dc.description.abstract | Drought stress is considered to be one of the most predominant abiotic stresses, causing a setback in crop production worldwide. Mustard is one among the major oil seed crops of India that is grown in rainfed lands. Recent studies indicate that employing osmotolerant rhizobacteria can help plants cope with drought stress which is an ecofriendly and cost-effective method. In the present investigation, eleven osmotolerant rhizobacterial cultures isolated from mustard and nagphani plants were evaluated for their effect on growth and yield of drought sensitive Brassica juncea variety Pusa Karishma LES-39 under water deficit stress condition. Plants inoculated with Bacillus cereus strain NAD-7 and Bacillus casamancensis strain MKS-6 exhibited superior performance in yield and growth, thus were selected for further studies. The effect of osmotic stress on mustard-rhizobacterial interactions was studied in detail. It was observed that osmotic stress significantly affected the rhizobacteriamustard root interaction. Also the quality and quantity of sugar monomers of both the rhizobacterial EPS was improved. The protein and phenolics profile of NAD-7 and MKS-6 were altered in the presence of osmotic stress. It was also found that several proteins of mustard roots were differentially expressed due to osmotic stress and inoculation treatment. Further, a pot experiment was conducted to determine the effect of inoculation with osmotolerant rhizobacterial strains NAD-7 and MKS-6 during vegetative and reproductive growth stages under drought stress conditions. It was observed that under drought stress, the inoculated plants exhibited better root and shoot biomass over uninoculated treatment during both stages. These observations led to investigation into the physiological, biochemical and molecular mechanisms involved. The inoculated plants outperformed in various parameters namely RWC, MSI and photosynthetic pigments in comparison to uninoculated conditions. The net photosynthetic rate, stomatal conductance and sugar contents were better in case of inoculated plants under drought stress. The proline content was significantly reduced by inoculation under drought stress during both stages and was interpreted as the improvement in plant health status by microbes. The H2O2 content of inoculated plants was lowered significantly and the activity of SOD, CAT and APX was significantly high in inoculated plants. Finally the hormonal regulation of plant growth was studied under drought during both stages. HPLC analysis of root samples showed that the level of auxin (IAA) was significantly higher in inoculated plants under stress that must have influenced the root growth during both stages. In leaves, the similar trend was followed for hormones namely GA and ABA. This also was explanatory to improved shoot growth and flowering. The expression of genes involved in the hormone biosynthetic pathways BjYUCCA1, BjNCED3 and BjGA20ox correlated with the hormone levels. Similarly, the transcript level of BjFeSOD and BjP5CSB, various stress signaling pathway genes namely BjDREB1-2, BjDREB2 and BjNAC14 were upregulated in inoculated plants under drought stress during both stages. The data on biomass, yield and oil content upon inoculation showed relatively superior performance even under drought stress conditions. It also appeared that the vegetative stage was more responsive to rhizobacterial inoculation than reproductive stage under drought. These investigations indicate the potency of rhizobacteria in reducing the negative impacts of drought stress in mustard. It can serve as potent biofertilizer to sustain crop production under stressed environment. Keywords :- Bacillus cereus, Rhizobacterial, Biosynthetic | en_US |
| dc.identifier.uri | https://krishikosh.egranth.ac.in/handle/1/5810175642 | |
| dc.keywords | Bacillus cereus, Rhizobacterial, Biosynthetic | en_US |
| dc.language.iso | English | en_US |
| dc.publisher | DIVISION OF MICROBIOLOGY ICAR- INDIAN AGRICULTURAL RESEARCHINSTITUTE NEW DELHI | en_US |
| dc.sub | Microbiology | en_US |
| dc.theme | Understanding interactions between osmotolerant rhizobacteria and mustard under water deficit stress conditions | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Understanding interactions between osmotolerant rhizobacteria and mustard under water deficit stress conditions | en_US |
| dc.type | Thesis | en_US |