Browsing by Author "Rahul Singh Rajput"

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A deeper insight into the symbiotic mechanism of Rhizobium spp. from the perspective of secondary metabolism
(Springer Singapore, 2019) Prachi Singh; Rahul Singh Rajput; Ratul Moni Ram; Harikesh Bahadur Singh
Rhizobia are group of organism, known globally for their nitrogen-fixing ability. In addition to nitrogen fixation, they significantly contribute to plant growth promotion and disease control. Rhizobial aptness for plant growth promotion and antagonism against a wide range of pathogens is due to its ability to produce a wide range of secondary metabolites such as HCN, siderophore, antibiotics, rhizobitoxin, lytic enzymes, IAA, phosphate solubilization and induced systemic resistance. Rhizobial inoculants, ascribed with multiple roles of nitrogen fixation, growth promotion and disease suppression, have strengthened crop productivity. This compilation urges the need to recognize and exploit the potential multifaceted secondary metabolites of rhizobia for biological control and growth promotion. © Springer Nature Singapore Pte Ltd. 2019.
A Thorough Comprehension of Host Endophytic Interaction Entailing the Biospherical Benefits: A Metabolomic Perspective
(Springer Science and Business Media B.V., 2019) Shatrupa Ray; Jyoti Singh; Rahul Singh Rajput; Smriti Yadav; Surendra Singh; Harikesh Bahadur Singh
Endophytism is the phenomenon of in planta residency and mutualistic association of microbes with hosts without causing any disease symptoms. The multifaceted attributes of endophytes include plant growth promotion as well as resistance of the host to several forms of abiotic or biotic stresses. Moreover, endophytes are reported to manipulate the rhizospheric microbiota as well as the microbiota present within plants so as to amplify the host beneficial mechanisms. Endophyte mediated host beneficial traits become far more significant owing to the differential recruitment of endophytes by host under varying root exudate profile, host’s age, as well as host-endophyte compatibility. However, in spite of such beneficial attributes, our understanding of endophytes is still quite limited and inadequate. Thus, the true potential of endophytes can be particularly harnessed when we gain a thorough insight on the molecular mechanisms responsible for mutualistic host-endophyte interaction. In this chapter, we present an exhaustive investigation of endophyte-plant interaction, beginning from chemotactic attraction of the supposed endophytic microflora from soil to establishment of endophytism. We will also focus on the endophyte-directed metabolite biosynthesis aiding in effective host functioning. © 2019, Springer Nature Switzerland AG.
Belowground fungal volatiles perception in okra (Abelmoschus esculentus) facilitates plant growth under biotic stress
(Elsevier GmbH, 2021) Jyoti Singh; Prachi Singh; Anukool Vaishnav; Shatrupa Ray; Rahul Singh Rajput; Shiv Mohan Singh; Harikesh Bahadur Singh
Microbial volatile organic compounds (mVOCs) have great potential in plant ecophysiology, yet the role of belowground VOCs in plant stress management remains largely obscure. Analysis of biocontrol producing VOCs into the soil allow detailed insight into their interaction with soil borne pathogens for plant disease management. A root interaction trial was set up to evaluate the effects of VOCs released from Trichoderma viride BHU-V2 on soil-inhabiting fungal pathogen and okra plant growth. VOCs released into soil by T. viride BHU-V2 inhibited the growth of collar rot pathogen, Sclerotium rolfsii. Okra plants responded to VOCs by increasing the root growth (lateral roots) and total biomass content. VOCs exposure increased defense mechanism in okra plants by inducing different enzyme activities i.e. chitinase (0.89 fold), β-1,3-glucanase (0.42 fold), peroxidase (0.29 fold), polyphenol oxidase (0.33 fold) and phenylalanine lyase (0.7 fold) when inoculated with S. rolfsii. In addition, T. viride BHU-V2 secreted VOCs reduced lipid peroxidation and cell death in okra plants under pathogen inoculated condition. GC/MS analysis of VOCs blend revealed that T. viride BHU-V2 produced more number of antifungal compounds in soil medium as compared to standard medium. Based on the above observations it is concluded that okra plant roots perceive VOCs secreted by T. viride BHU-V2 into soil that involved in induction of plant defense system against S. rolfsii. In an ecological context, the findings reveal that belowground microbial VOCs may play an important role in stress signaling mechanism to interact with plants. © 2021
Exploration of multitrait antagonistic microbes against Fusarium oxysporum f.sp. lycopersici
(Applied and Natural Science Foundation, 2019) Prachi Singh; Jyoti Singh; Rahul Singh Rajput; Anukool Vaishnav; Shatrupa Ray; R.K. Singh; H.B. Singh
Fusarium wilt is one of the major diseases of tomato causing extensive loss of production. Exploration of agriculturally important microbes (AIMs) for management of the tomato wilt is an ecofriendly and cost effective approach. In the present study, a total 30 Trichoderma and 30 bacterial isolates were screened in the laboratory for their biocontrol activity against Fusarium oxysporum f.sp. lycopersici (FOL). Out of all the isolates tested, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 were found to show maximum inhibition of FOL in dual culture assay. Both the microbes also exhibited plant growth promoting activities such as phosphate solubilisation, production of siderophore, hydrogen cyanide (HCN), indole acetic acid (IAA) and protease activity. These microbes could be evaluated further in greenhouse and field studies for their potential use in management of Fusarium wilt of tomato. © 2019, Applied and Natural Science Foundation. All rights reserved.
Influence of Seed Biopriming and Vermiwash Treatment on Tomato Plant's Immunity and Nutritional Quality upon Sclerotium rolfsii Challenge Inoculation
(Springer, 2021) Rahul Singh Rajput; Jyoti Singh; Prachi Singh; Anukool Vaishnav; Harikesh Bahadur Singh
Tomato is an important nutritional vegetable crop and its nutrient contents are affected by both biotic and abiotic stresses. The main objective of this study was to determine the effect of seed biopriming with Trichoderma pseudokoningii BHUR2 and vermiwash treatment on nutrient content of tomato and defense response against Sclerotium rolfsii under heat stress condition. The combined application of T. pseudokoningii BHUR2 and vermiwash increased fresh weight of root (4.8-fold) and shoot (5.8-fold), dry weight of root (6.9-fold) and shoot (6.4-fold) and number of fruits per plant (4.2-fold) as compared to control under S. rolfsii inoculated condition. Plants treated with T. pseudokoningii BHUR2 and vermiwash exhibited higher defense response against S. rolfsii, mediated by higher activity of superoxide dismutase (3.57-fold), peroxidase (2.05-fold) and phenylalanine ammonia lyase (2.98-fold) enzymes and accumulation of total phenol content (5.35-fold) as compared to control plants. In addition, combined treatment was found to have a positive impact on nutritional status (N, P, K and Ca and lycopene, total soluble sugar and total protein) in tomato fruit. These results suggest potential of T. pseudokoningii BHUR2 and vermiwash in enhancing tomato immunity against S. rolfsii under heat stress condition, which was due to (1) induction in the antioxidant activity and phenylpropanoid pathway, which minimize oxidative damage and reduce pathogen infection and (2) significant improvement in nutrient content leads to better plant growth. The formulation of Trichoderma BHUR2 can be used for field application to mitigate heat stress in plants. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
Microbe-based novel biostimulants for sustainable crop production
(Springer Singapore, 2019) Rahul Singh Rajput; Ratul Moni Ram; Anukool Vaishnav; Harikesh Bahadur Singh
The emerging status and scope of microbial products for better plant growth and prevention of diseases have attracted attention of researchers, industrialists to promote this field and farmers to utilize them as microbial stimulants. The hazardous impact of chemical fungicides in our ecosystem can also be mitigated through these strategies. Owing to the multifarious applications of biostimulants, agriculturally important microorganisms (AIMs) have been incorporated in agricultural system as biofertilizers and biopesticides. AIMs employed multiple mechanisms including nutrient solubilization, production of siderophores, phytohormone, antimicrobial compounds and volatiles, ACC deaminase and exopolysaccharide to work as biostimulant for alleviation of abiotic and biotic stresses in plants. In the present chapter, a comprehensive study on microbial biostimulants has been emphasized to confer their growth promoting and stress alleviation activities in plants. This would surely facilitate in a profound perception about mechanism of the plant-microbe interaction. Once a better knowledge developed about the governing action mechanisms of the microbe-based biostimulants is made, it will be easy to target next generation of biostimulants which may have multitargeted approach. © Springer Nature Singapore Pte Ltd. 2019.
Mycorrhiza Based Approaches for Soil Remediation and Abiotic Stress Management
(Springer Singapore, 2019) Ratul Moni Ram; Prakash Jyoti Kalita; Rahul Singh Rajput; H.B. Singh
Anthropogenic activities have resulted into degradation of land and water bodies. Excessive mining activities lead to the contamination of nearby areas with heavy metals viz. Pb, As, Cd, Zn etc. All these elements are highly toxic to the plants when they are exposed at a higher concentration. Apart from these heavy metals even the excessive use of fertilizers, herbicides and unmetabolized antibiotics from livestock farming can also leaves considerable amount of toxic residues in the soil which hinder the overall growth of plants. In addition to this, abiotic stresses viz. drought stress, salt stress, osmotic stress and ozone stress etc. also limits the crop production. The level of their impact on the different crops across the globe varies depending upon the geographical location and unscrupulous human activities but altogether it results into a huge annual loss to the global crop productivity. Several approaches have been designed to figure out the stress right from artificial to biological. The biological approach includes the use of living organism for stress alleviation among which Arbuscular Mycorrhizal fungi (AMF) emerged as a potent tool for stress alleviation and phytoremediation. The term “phytoremediation” has got more and more attention over the past decade. Due to the multifaceted applications of AMF, it has been widely used as a xenobiotic tool. © Springer Nature Singapore Pte Ltd. 2019.
Plant Growth-Promoting Rhizobacteria: Benign and Useful Substitute for Mitigation of Biotic and Abiotic Stresses
(Springer, 2019) Jyoti Singh; Prachi Singh; Shatrupa Ray; Rahul Singh Rajput; Harikesh Bahadur Singh
An incessant increase in global population along with a continuous augmentation in abiotic stress conditions, such as temperature, pH, salinity, etc., and limitation of natural resources has posed a serious threat to developing nations in terms of food security and enhanced nutritional value of the yield. Substantial crop losses in both qualitative and quantitative aspects due to the several prevalent phytopathogens are adding severity to the existing trouble. Confrontation with this ongoing problem initially led to the application of chemical fertilizers. However, hazardous aftereffects of the chemical fertilizers on the ecosystem have instigated a demand for a promising eco-friendly substitute that deals with both biotic and abiotic stresses. Rhizospheric microorganisms can be utilized as an effective alternative because they reside in soil and have the intrinsic property of upholding balanced ecosystem. These plant growth-promoting rhizobacteria (PGPRs) enhance plant growth even in poor and stressed environmental conditions by the formation of beneficial associations with the host through biological nitrogen fixation, phosphate solubilization, siderophore and hormone production, etc. They can also trigger host defense mechanism through induced systemic resistance (ISR). These PGPRs are also helpful for phytoremediation by various processes such as direct absorption, accumulation, etc. PGPRs are utilized in the fields of phytostimulation, biofertilization, and biocontrol activities. In the current chapter, we would aim to uphold the mechanisms opted by PGPR for effective plant growth promotion and defense under various abiotic as well as biotic stress conditions. In this context, we would also aim to delve in detail about the host-PGPR cross talk during the onset of stress conditions. © Springer Nature Singapore Pte Ltd. 2019.
Seed Biopriming Through Beneficial Rhizobacteria for Mitigating Soil-Borne and Seed-Borne Diseases
(Springer, 2019) Rahul Singh Rajput; Prachi Singh; Jyoti Singh; Shatrupa Ray; Anukool Vaishnav; Harikesh Bahadur Singh
Seed priming enables seed hydration, thereby activating its metabolism without substantial germination. It also assists in rapid germination as well as enhances resistance to both biotic and abiotic stresses. Soilborne pathogens such as Sclerotium rolfsii, Sclerotinia sclerotiorum, and Rhizoctonia possess major threat to crop production on a global scale. These pathogens cause diseases at the time of seed germination; hence, seed biopriming approach will be advantageous for early crop protection. Further, seed biopriming also providing greater protection by biocontrol increased adherence to seed surface. Thereby biocontrol agents will be establishing prior to pathogen infection. In this context, seed biopriming is a promising technique in comparison to seed treatment, soil application, and foliar spray, thereby providing a significant contribution to sustainable agriculture. © Springer Nature Singapore Pte Ltd. 2019.
Seed biopriming with antagonistic microbes and ascorbic acid induce resistance in tomato against Fusarium wilt
(Elsevier GmbH, 2020) Prachi Singh; Jyoti Singh; Shatrupa Ray; Rahul Singh Rajput; Anukool Vaishnav; Rakesh Kumar Singh; Harikesh Bahadur Singh
Seed biopriming is an emerging technique to enhance seed germination under stress conditions. An integrated approach of tomato seed biopriming with ascorbic acid, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 was applied to observe the response against wilt pathogen of tomato Fusarium oxysporum f. sp. lycopersici (FOL). Tomato seeds bioprimed with the aforementioned application expressed augmented seed germination and activated of defense response. Seed germination was recorded higher (80 %) at low concentration (1 pM) of ascorbic acid as compared to high concentration of 1 mM (41 %). Combination of both ascorbic acid and antagonistic microbe treatments (T5 & T6) significantly reduced disease incidence (up to 28 %) in tomato plants at 10 days. T5 and T6 treated plants exhibited higher accumulation of total phenol content and increased activity of Phenylammonia lyase (PAL), Peroxidase (PO), Chitinase (Chi) and Polyphenol oxidase (PPO) as compared to control (T1) plants. ROS formation in the form of H2O2 was also found to be reduced in combined treatment. Histochemical analysis revealed that phenylpropanoid pathway (lignin deposition) was more activated in combined priming treatment plants as compared to individual treatment upon challenge inoculation with FOL. Transcript expression analysis of defense genes confirmed the up-regulation of PAL (2.1 fold), Chi (0.92 fold), Pathogenesis related proteins (PR) (1.58 fold) and Lipoxygenase (Lox) (0.72 fold) in T6 treatment as compared to T1 treatment plants at 96 h. This study reveals that ascorbic acid treatment with antagonistic microbes through seed priming effectively induced seed germination and elicited defense mechanism to control wilt disease in tomato plants. © 2020 Elsevier GmbH
Sheath blight and drought stress management in rice (Oryza sativa) through Trichoderma spp.
(Springer, 2020) Divya Mishra; Rahul Singh Rajput; Najam Waris Zaidi; H.B. Singh
Sheath blight of rice caused by Rhizoctonia solani Kuhn is a major rice diseases worldwide, and cause up to 50% yield losses depending upon its severity. Native biocontrol agents were isolated from rice rhizospheric soil of different region and NADEP compost. Fourteen strains of Trichoderma were isolated and screened in vitro against Rhizoctonia solani causing sheath blight of rice through dual culture technique. Among all tested isolates under in vitro conditions Trichoderma BHU-11, T-4 and BHU-8 showed the maximum inhibition for Rhizoctonia solani (71.48%, 67.28% and 63.89%, respectively). These strains of Trichoderma were also taken for checking drought tolerance in rice crop. Trichoderma strains when applied as seed + root dip treatment showed reduction of disease incidence. It also acted as plant growth promoter and increased the number of tillers/hill, plant height and yield of the crop. Trichoderma alters the drought response including drought avoidance through different morpho-physiological and biochemical adaptations, and enhanced drought recovery. The root colonization by Trichoderma increased the growth of roots and plant productivity. Biochemical studies showed the ability of Trichoderma BHU-11, T-4 and BHU-8 to produce high level phenol and proline contents in Trichoderma treated stress challenged plants and higher accumulation of chlorophyll in Trichoderma treated plants. © 2019, Indian Phytopathological Society.
Sphingobacterium sp. BHU-AV3 Induces Salt Tolerance in Tomato by Enhancing Antioxidant Activities and Energy Metabolism
(Frontiers Media S.A., 2020) Anukool Vaishnav; Jyoti Singh; Prachi Singh; Rahul Singh Rajput; Harikesh Bahadur Singh; Birinchi K. Sarma
Salt tolerant bacteria can be helpful in improving a plant’s tolerance to salinity. Although plant–bacteria interactions in response to salt stress have been characterized, the precise molecular mechanisms by which bacterial inoculation alleviates salt stress in plants are still poorly explored. In the present study, we aimed to determine the role of a salt-tolerant plant growth-promoting rhizobacteria (PGPR) Sphingobacterium BHU-AV3 for improving salt tolerance in tomato through investigating the physiological responses of tomato roots and leaves under salinity stress. Tomato plants inoculated with BHU-AV3 and challenged with 200 mM NaCl exhibited less senescence, positively correlated with the maintenance of ion balance, lowered reactive oxygen species (ROS), and increased proline content compared to the non-inoculated plants. BHU-AV3-inoculated plant leaves were less affected by oxidative stress, as evident from a reduction in superoxide contents, cell death, and lipid peroxidation. The reduction in ROS level was associated with the increased antioxidant enzyme activities along with multiple-isoform expression [peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD)] in plant roots. Additionally, BHU-AV3 inoculation induced the expression of proteins involved in (i) energy production [ATP synthase], (ii) carbohydrate metabolism (enolase), (iii) thiamine biosynthesis protein, (iv) translation protein (elongation factor 1 alpha), and the antioxidant defense system (catalase) in tomato roots. These findings have provided insight into the molecular mechanisms of bacteria-mediated alleviation of salt stress in plants. From the study, we can conclude that BHU-AV3 inoculation effectively induces antioxidant systems and energy metabolism in tomato roots, which leads to whole plant protection during salt stress through induced systemic tolerance. © Copyright © 2020 Vaishnav, Singh, Singh, Rajput, Singh and Sarma.
Trichoderma: A part of possible answer towards crop residue disposal
(Applied and Natural Science Foundation, 2019) O. Siva Devika; Subhadip Paul; Deepranjan Sarkar; Rahul Singh Rajput; Sonam Singh; Manoj Parihar; H.P. Parewa; Sumita Pal; H.B. Singh; Amitava Rakshit
India is one of the leading countries in agricultural production and generate large volume of crop residue. Increasing demand for food grains due to growing population leads to generation of crop residues. Due to lack of proper disposal mechanism of crop residue, farmers burn the residue which release greenhouse gases (GHGs) into the atmosphere, and poses great threat to environment as well as human health. The residue burning causes greater carbon emission and nutrient losses which otherwise incorporated into the soil system may substantially improve the soil biodiversity. Besides several practices of crop residue management, the most feasible method for farmers is incorporation of residue into the soil with the inoculation of microbes. In soil system the ability of microbial community in degrading organic substances is well known. In the early stages of residue decomposition simple substrates like carbohydrates are degraded by bacteria, but in later stages degradation of complex constituents viz., cellulose, lignin needs microbes which are capable of secreting enzymes like cellulase, acting on complex organic substrates. In this context, cellulolytic micro organisms like Trichoderma have the potential and emerging as an important microbial inoculants to enhance the rate of decomposition as well as alleviate the effect of residue burning. © 2019, Applied and Natural Science Foundation. All rights reserved.