Browsing by Author "Ajit Varma"

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Comparative expression analysis of defence-related genes in Bacillus-treated Glycine max upon challenge inoculation with selective fungal phytopathogens
(Indian Academy of Sciences, 2018) Shekhar Jain; Anukool Vaishnav; Ajit Varma; Devendra Kumar Choudhary
Activation of defence-related genes by the application of beneficial bacteria leads to prior protection against pathogens through induced systemic resistance. The present study was carried out to examine the qRT- PCR-based relative quantification of differently expressed defence-related genes in soybean (Glycine max L. Merrill) plants primed with Bacillus sp. strain SJ-5 against the fungal pathogen Rhizoctonia solani and Fusarium oxysporum. In this context, molecular characterization of plant growth promoting and biocontrol genes of SJ-5 was done by PCR followed by homology analysis. In the GC-MS analysis of SJ-5 volatile organic compounds, potent antifungal compound bis(2-ethylhexyl) phthalate and antioxidant compound butylated hydroxy toluene were reported with the highest peak area 47.96% and 21.82% respectively, along with other antifungal compounds in small proportion. Qualitative expression of different defence-related genes like lipoxygenase, phenylalanine ammonia-lyase 2, peroxidase, polyphenol oxidase, endo-1,3-beta-glucanase, catalase, defensin-like protein, vegetative storage protein and chitinase class I was found elicited in the plants primed with SJ-5 against the fungal pathogens. In the qPCR analysis, the highest upregulation was observed in the transcript profile of ppojh2 in the treatments T5 and T6 with 4.12- and 4.06-fold increase respectively. © 2018 Current Science Association, Bengaluru.
Influence of cellulolytic organisms associated with a termite, Odontotermes obesus, on carbon mobility in a semiarid ecosystem
(1988) Aditi Sarkar; Ajit Varma; Asit Sarkar
The heterotrophic microbial activity of Odontotermes obesus gut and mound soil of the semiarid zone of Delhi, India was examined by implying enrichments technique. The cellulose degraders along with the total bacterial population of the mounds were lowest in summer months, but no relative decline of cellulose degraders was observed in comparison to the total population. The feeding habit of Odontotermes was associated with the gut inhabitants Staphylococcus, Micrococcus luteus, M. roseus, and with soil inhabitants Bacillus “thermoalcaliphilus” and Cellulomonas sp. M. luteus and M. roseus degrade various types of cellulose by producing endogenous and exogenous cellulose in vitro. As cellulose and lignocellu- lose are the organic C sources available in soil, the conversion of cellulosic detritus to bacterial biomass can be expected to constitute a significant flow of carbon and energy from plant to bacteria and, therefore, to animals in these ecosystems. © 1988 Taylor & Francis.
Modulation in Biofertilization and Biofortification of Wheat Crop by Inoculation of Zinc-Solubilizing Rhizobacteria
(Frontiers Media S.A., 2022) Ramesh Chandra Yadav; Sushil K. Sharma; Ajit Varma; Mahendra Vikram Singh Rajawat; Mohammad Shavez Khan; Pawan K. Sharma; Deepti Malviya; Udai B. Singh; Jai P. Rai; Anil K. Saxena
Zinc is an important micronutrient needed for the optimum growth and development of plants. Contrary to chemical zinc fertilizers, the use of zinc-solubilizing bacteria is an environmentally friendly option for zinc enrichment in edible parts of crops. This study was conducted with the objective of selecting potential zinc-solubilizing rhizobacteria from the rhizosphere of chickpea grown in soils of eastern Uttar Pradesh and further assessing their impact on the magnitude of zinc assimilation in wheat crops. Among 15 isolates, CRS-9, CRS-17, CRS-30, and CRS-38 produced net soluble zinc in broth to the tune of 6.1, 5.9, 5.63, and 5.6 μg ml–1, respectively, in zinc phosphate with the corresponding pH of 4.48, 5.31, 5.2, and 4.76. However, the bacterial strains CRS-17, CRS-30, CRS-38, and CRS-9 showed maximum zinc phosphate solubilization efficiency of 427.79, 317.39, 253.57, and 237.04%, respectively. The four bacterial isolates were identified as Bacillus glycinifermentans CRS-9, Microbacterium oxydans CRS-17, Paenarthrobacter nicotinovorans CRS-30, and Bacillus tequilensis CRS-38 on the basis of morphological and biochemical studies and 16S rRNA gene sequencing. Bacterial inoculants significantly colonized the roots of wheat plants and formed a biofilm in the root matrix. These strains significantly increased seed germination (%) and vigor indices in wheat grown under glasshouse conditions. After 30 days of sowing of wheat under microcosm conditions, eight zinc transporter (TaZIP) genes were expressed maximally in roots, with concomitant accumulation of higher zinc content in the bacterially treated plant compared to the absolute control. Out of the four strains tested, two bacteria, B. tequilensis CRS-38 and P. nicotinovorans CRS-30, improved seed germination (%), vigor indices (2–2.5 folds), plant biomass, grain yield (2.39 g plant–1), and biofortificated grains (54.25 μg g–1Zn) of wheat. To the best of our knowledge, this may be the first report on the presence of zinc solubilization trait in B. glycinifermentans CRS-9, M. oxydans CRS-17, and P. nicotinovorans CRS-30. Copyright © 2022 Yadav, Sharma, Varma, Rajawat, Khan, Sharma, Malviya, Singh, Rai and Saxena.
Zinc-solubilizing Bacillus spp. in conjunction with chemical fertilizers enhance growth, yield, nutrient content, and zinc biofortification in wheat crop
(Frontiers Media SA, 2023) Ramesh Chandra Yadav; Sushil K. Sharma; Ajit Varma; Udai B. Singh; Adarsh Kumar; Ingudam Bhupenchandra; Jai P. Rai; Pawan K. Sharma; Harsh V. Singh
Micronutrient deficiency is a serious health issue in resource-poor human populations worldwide, which is responsible for the death of millions of women and underage children in most developing countries. Zinc (Zn) malnutrition in middle- and lower-class families is rampant when daily calorie intake of staple cereals contains extremely low concentrations of micronutrients, especially Zn and Fe. Looking at the importance of the problem, the present investigation aimed to enhance the growth, yield, nutrient status, and biofortification of wheat crop by inoculation of native zinc-solubilizing Bacillus spp. in conjunction with soil-applied fertilizers (NPK) and zinc phosphate in saline soil. In this study, 175 bacterial isolates were recovered from the rhizosphere of wheat grown in the eastern parts of the Indo-Gangetic Plain of India. These isolates were further screened for Zn solubilization potential using sparingly insoluble zinc carbonate (ZnCO3), zinc oxide (ZnO), and zinc phosphate {Zn3(PO4)2} as a source of Zn under in vitro conditions. Of 175 bacterial isolates, 42 were found to solubilize either one or two or all the three insoluble Zn compounds, and subsequently, these isolates were identified based on 16S rRNA gene sequences. Based on zone halo diameter, solubilization efficiency, and amount of solubilized zinc, six potential bacterial strains, i.e., Bacillus altitudinis AJW-3, B. subtilis ABW-30, B. megaterium CHW-22, B. licheniformis MJW-38, Brevibacillus borstelensis CHW-2, and B. xiamenensis BLW-7, were further shortlisted for pot- and field-level evaluation in wheat crop. The results of the present investigation clearly indicated that these inoculants not only increase plant growth but also enhance the yield and yield attributes. Furthermore, bacterial inoculation also enhanced available nutrients and microbial activity in the wheat rhizosphere under pot experiments. It was observed that the application of B. megaterium CHW-22 significantly increased the Zn content in wheat straw and grains along with other nutrients (N, P, K, Fe, Cu, and Mn) followed by B. licheniformis MJW-38 as compared to other inoculants. By and large, similar observations were recorded under field conditions. Interestingly, when comparing the nutrient use efficiency (NUE) of wheat, bacterial inoculants showed their potential in enhancing the NUE in a greater way, which was further confirmed by correlation and principal component analyses. This study apparently provides evidence of Zn biofortification in wheat upon bacterial inoculation in conjunction with chemical fertilizers and zinc phosphate in degraded soil under both nethouse and field conditions. Copyright © 2023 Yadav, Sharma, Varma, Singh, Kumar, Bhupenchandra, Rai, Sharma and Singh.