Browsing by Author "Sushil K. Sharma"

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Bio-protective microbial agents from rhizosphere eco-systems trigger plant defense responses provide protection against sheath blight disease in rice (Oryza sativa L.)
(Elsevier GmbH, 2016) Udai B. Singh; Deepti Malviya; Wasiullah; Shailendra Singh; Jatindra K. Pradhan; Bhanu P. Singh; Manish Roy; Mohd Imram; Neelam Pathak; B.M. Baisyal; Jai P. Rai; B.K. Sarma; Rajiv K. Singh; P.K. Sharma; Saman Deep Kaur; M.C. Manna; Sushil K. Sharma; Arun K. Sharma
Sheath blight of rice (Oryza sativa L.) caused by Rhizoctonia solani is a major disease and attempts are being made to develop microbe based technologies for biocontrol of this pathogen. However, the mechanisms of biocontrol are not fully understood and still require indepth study in the backdrop of emerging concepts in biological systems. The present investigation was aimed at deciphering the mechanisms of biocontrol of sheath blight of rice employing Pseudomonas fluorescens and Trichoderma harzianum as model agents for biocontrol. Initially 25, 5 and 5 strains of P. fluorescens, T. viride and T. harzianum, respectively, were screened for their biocontrol potential. Out of which, six strains with higher value of percent inhibition of fungal mycelium in dual plate assay were selected. The role of P. fluorescens, T. viride and T. harzianum were investigated in induction and bioaccumulation of natural antioxidants, defence-related biomolecules and other changes in plant which lead not only to growth promotion but also protection from pathogenic stress conditions in rice. The two most promising strains, P. fluorescens PF-08 and T. harzianum UBSTH-501 selected on the basis of in planta evaluation, when applied individually or in combination, significantly enhanced the accumulation of defence-related biomolecules, enzymes and exhibited biocontrol potential against R. solani. A modified/newly developed delivery system was applied for the first time in the experiments involving inoculation of plants with both bioagents, viz. P. fluorescens PF-08 and T. harzianum UBSTH-501. Results suggested that application of P. fluorescens PF-08 and T. harzianum UBSTH-501 alone or in combination, not only helps in control of the disease but also increases plant growth along with reduction in application of toxic chemical pesticides. © 2016 Elsevier GmbH
Drechslerella dactyloides and Dactylaria brochopaga mediated induction of defense related mediator molecules in tomato plants pre-challenged with Meloidogyne incognita
(Springer, 2019) Udai B. Singh; Shailendra Singh; Wasiullah Khan; Deepti Malviya; Pramod K. Sahu; Rajan Chaurasia; Sushil K. Sharma; A.K. Saxena
The present investigation was aimed to isolate and characterize the strains of Drechslerella dactyloides and Dactylaria brochopaga from decaying root galls of tomato in order to investigate their role in reprogramming of root apoplast that enhance defence responses in tomato pre-challenged with Meloidogyne incognita. Out of 23 strains of D. brochopaga and D. dactyloides were isolated from decaying root galls of tomato, three strains of D. dactyloides and five strains of D. brochopaga were found effective and these were selected for further characterization under controlled laboratory conditions. Further, D. dactyloides NDAd-05 and D. brochopaga NDDb-15 were found most promising strains for control of M. incognita. The study elucidates multifarious effects of D. dactyloides NDAd-05 and D. brochopaga NDDb-15 inoculated either individually or in combination on tomato plants pre-challenged with M. incognita under nethouse conditions. Results of this investigation revealed that inoculation of D. dactyloides NDAd-05 and D. brochopaga NDDb-15 increased various attributes in plants to significant degree conferring defence against M. incognita. Both the strains were found to have potential to enhance site-specific accumulation and activation of defence-related mediator molecules, enzymes and thus, exhibited biocontrol potential against M. incognita. Further, application of D. dactyloides NDAd-05 and D. brochopaga NDDb-15 not only assisted in the growth promotion but also activated phenylpropanoid pathway in root apoplast in addition to direct trapping of M. incognita. © 2019, Indian Phytopathological Society.
Drechslerella dactyloides and Dactylaria brochopaga mediated structural defense in tomato plants pre-challenged with Meloidogyne incognita
(Academic Press Inc., 2020) Udai B. Singh; Shailendra Singh; Deepti Malviya; Rajan Chaurasia; Pramod K. Sahu; Sushil K. Sharma; A.K. Saxena
The present study was undertaken with the objectives to study Drechslerella dactyloides NDAd-05 and Dactylaria brochopaga NDDb-15 mediated induction of structural defense responses leading to lower disease development and promoting growth in tomato pre-challenged with Meloidogyne incognita. The potential strains D. dactyloides NDAd-05 and D. brochopaga NDDb-15 were taken from Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Kushmaur, Maunath Bhanjan, India. In vitro root colonization assay was performed using D. dactyloides NDAd-05 and D. brochopaga NDDb-15 in sand:soil culture (2:1) and significant tomato root colonization by NDAd-05 and NDDb-15 was recorded. The study elucidated multifarious effects of D. dactyloides NDAd-05 and D. brochopaga NDDb-15 when inoculated either individually or in combination in tomato plants pre-challenged with M. incognita. Additionally, D. dactyloides NDAd-05 and D. brochopaga NDDb-15 increased antioxidant as well as biocontrol activities significantly in tomato against M. incognita. Microscopic visualization of H2O2 and superoxide radicals in tomato leaves further corroborated the above findings. Further, inoculation of D. dactyloides NDAd-05 and D. brochopaga NDDb-15 activated the phenylpropanoid pathway in roots leading to increase cell wall lignifications and pectin deposition in tomato roots in addition to direct trapping and parasitizing of juveniles and adults of M. incognita. From the results it can be concluded that increased cell wall lignifications and pectin deposition probably restricted the entry of nematodes and ultimately decreased the M. incognita population in tomato roots. It was also observed that plants treated with bioagents individually or in combination modulated the phenotypical alterations and assisted plant growth promotion. This might be due to the interaction-dependent modulation of physio-biochemical pathways in the tomato plants which ultimately reduced the inoculum potential and disease intensity of M. incognita. © 2020 Elsevier Inc.
Engineering the Plant Microbiome for Biotic Stress Tolerance: Biotechnological Advances
(Springer, 2022) Deepti Malviya; Talat Ilyas; Rajan Chaurasia; Udai B. Singh; Mohammad Shahid; Shailesh K. Vishwakarma; Zaryab Shafi; Bavita Yadav; Sushil K. Sharma; Harsh V. Singh
The transformation of rhizosphere microbiota is essentially the result of a series of events that can enhance the formation of constant and different microbial associations in the plant microbiome/holobiome based on supportive information/communications. Beneficial microbial communities act as influential identities for the elevation of ecological stresses in plants and ultimately decrease the usage of fertilizer and pesticides in order to increase the crop yield. Microbiome has the capability to stimulate the growth of plants, develop resistance to stress, and enhance the health of plants. To accomplish these objectives, it is essential to learn more about the relationship between plant, microbiome, microbial community present in soil, and their resilience to environmental changes. The information acquired will help in understanding the effect of these microorganisms on the biotic resistance, biogeochemical cycles, and productivity of the crops. A comprehensive understanding of the biological mechanisms underlying stress-induced microbiome modifications would also allow for the development of personalized DefenseBiomes and chemicals in order to combat with crop stresses. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.
Microbial Interactions in the Rhizosphere Contributing Crop Resilience to Biotic and Abiotic Stresses
(Springer, 2020) Deepti Malviya; Udai B. Singh; Shailendra Singh; Pramod K. Sahu; K. Pandiyan; Abhijeet S. Kashyap; Nazia Manzar; Pawan K. Sharma; H.V. Singh; Jai P. Rai; Sushil K. Sharma
Rhizosphere is a hot spot where specific kinds of diverse microbial communities develop under the influence of exudates from plant roots and in turn modulate growth and development of the plant. Such communities with or without interactions perform an array of functions, including nitrogen fixation, P, Zn, Si and K-solubilization, siderophore production, ammonification, hormones production, ACC deaminase production, ethylene production, anammox, comammox, nitrification, denitrification, antagonisms, induce resistance to plant, C-sequestration, volatile production, secondary metabolites production and many others that are known to modulate soil and plant health contributing to the corresponding responses to various stresses of biotic and abiotic nature. The magnitude of resilience of plant to biotic and abiotic stresses is completely dependent on types of communities and their interactions. With enhanced knowledge and understanding about rhizosphere, researchers are evaluating various approaches to engineer rhizosphere in such way that it enables plant to enhance the productivity and sustain it while maintaining soil health. This chapter highlights detailed account of microbial interactions in the rhizosphere with associated mechanisms that contribute to resilience of plants to stress for better growth and development. © Springer Nature Singapore Pte Ltd. 2020.
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.