Browsing by Author "Shree P. Pandey"

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A halotolerant growth promoting rhizobacteria triggers induced systemic resistance in plants and defends against fungal infection
(Nature Publishing Group, 2019) Sandeep Sharma; Chen Chen; Sudhir Navathe; Ramesh Chand; Shree P. Pandey
A halotolerant rhizobacteria, Klebsiella species (referred to MBE02), was identified that had a growth stimulation effect on peanut. To gain mechanistic insights into how molecular components were reprogrammed during the interaction of MBE02 and peanut roots, we performed deep RNA-sequencing. In total, 1260 genes were differentially expressed: 979 genes were up-regulated, whereas 281 were down-regulated by MBE02 treatment as compared to uninoculated controls. A large component of the differentially regulated genes were related to phytohormone signalling. This included activation of a significant proportion of genes involved in jasmonic acid, ethylene and pathogen-defense signalling, which indicated a role of MBE02 in modulating plant immunity. In vivo and in vitro pathogenesis assays demonstrated that MBE02 treatment indeed provide fitness benefits to peanut against Aspergillus infection under controlled as well as field environment. Further, MBE02 directly reduced the growth of a wide range of fungal pathogens including Aspergillus. We also identified possible molecular components involved in rhizobacteria-mediated plant protection. Our results show the potential of MBE02 as a biocontrol agent in preventing infection against several fungal phytopathogens. © 2019, The Author(s).
A Klebsiella rhizobacterium deregulates the metabolism of phytopathogenic Aspergillus flavus during in-vitro assays and confers protective functions
(Elsevier B.V., 2024) Shree P. Pandey; Shivam Singh; Deepesh Khandwal; Avinash Mishra; Bhagya Shree Acharya; Suman Bakshi; Sundeep Kumar; Vinod Mishra; Sandeep Sharma
In previous investigations, we have identified a rhizobacterium (Klebsiella sp. MBE02) that confers host protection against several phytopathogenic fungi. For instance, this rhizobacterium prevents Aspergillus flavus infection and promotes peanut growth and fitness in controlled and field-conditions. The mechanistic basis of the protective function offered by this rhizobacterium is not completely understood. MBE02 directly restricts the growth of the pathogenic fungi, which led us to hypothesize that it may strongly dysregulate the metabolism of A. flavus, and inhibit critical metabolic processes of the fungus, which severely restricts pathogen growth. We have tested this hypothesis by using untargeted metabolite profiling. Sixty-nine A. flavus metabolites accumulated differentially due to the presence of the MBE02. MBE02 could inhibit several important metabolic pathways, which include the biosynthesis of critical primary metabolites such as amino acids and fatty acids. It also impacts energy metabolism of the fungus, and that the accumulation of several structural components, including of the cell wall, were strongly inhibited. MBE02 abrogated the accumulation of disease-causing metabolites in A. flavus, whereas the accumulation of metabolites that inhibit fungal growth were enhanced. On the other hand, A. flavus did not strikingly impact the accumulation of metabolites of the MBE02. Our investigation supports the hypothesis that Klebsiella sp. MBE02 mediates protective function by directly impairing the pathogen's metabolism. © 2024 The Authors
Clonal variability and its relevance in generation of new pathotypes in the spot blotch pathogen, Bipolaris sorokiniana
(2008) Shree P. Pandey; Sandeep Sharma; R. Chand; P. Shahi; A.K. Joshi
Spot blotch pathogen Bipolaris sorokiniana of wheat was investigated with threefold objectives: to establish a relationship between morphological and pathological variability of isolates, identify clonal genotype(s) acting as a source for the generation of new variability, and to determine the mechanism of generation of such variability in the pathogen. Isolates were collected from the leaves and seeds of field-grown wheat crop at four different sites in eastern Gangetic plains of India. Eighty-six clonal isolates derived from a single isolate (gray with white patches, Group III), which segregated in an equal proportion of parental and nonparental types, were studied. Morphological characters-i.e., colony morphology, growth rate, and sporulation-were studied along with disease-causing ability of the isolate clones. Clonal isolates were grouped into three categories. Microscopic analysis of nuclei was done to determine the causes of such variability. Morphological variability appeared to be related to the pathological variability. The isolate having epidemic potential appeared different than that acting as the reservoir for variability. The cause of such variability could be attributed either to hyphal fusion and heterokaryosis, nuclear migration and occurrence of multinucleate state, or a combination of these factors. Random Amplified Polymorphic DNA (RAPD) assay suggested that the unique fragments for different groups could be utilized as molecular markers to identify the isolates of specific groups. © 2007 Springer Science+Business Media, LLC.
Diversity in Indian barley (Hordeum vulgare) cultivars and identification of genotype-specific fingerprints using microsatellite markers
(Springer India, 2013) S.K. Jaiswal; Shree P. Pandey; S. Sharma; R. Prasad; L.C. Prasad; R.P.S. Verma; Arun K. Joshi
[No abstract available]
Elucidation of defense-related signaling responses to spot blotch infection in bread wheat (Triticum aestivum L.)
(Blackwell Publishing Ltd, 2016) Ranabir Sahu; Murali Sharaff; Maitree Pradhan; Avinash Sethi; Tirthankar Bandyopadhyay; Vinod K. Mishra; Ramesh Chand; Apurba K. Chowdhury; Arun K. Joshi; Shree P. Pandey
Spot blotch disease, caused by Bipolaris sorokiniana, is an important threat to wheat, causing an annual loss of ~17%. Under epidemic conditions, these losses may be 100%, yet the molecular responses of wheat to spot blotch remain almost uncharacterized. Moreover, defense-related phytohormone signaling genes have been poorly characterized in wheat. Here, we have identified 18 central components of salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and enhanced disease susceptibility 1 (EDS1) signaling pathways as well as the genes of the phenylpropanoid pathway in wheat. In time-course experiments, we characterized the reprogramming of expression of these pathways in two contrasting genotypes: Yangmai #6 (resistant to spot blotch) and Sonalika (susceptible to spot blotch). We further evaluated the performance of a population of recombinant inbred lines (RILs) by crossing Yangmai#6 and Sonalika (parents) and subsequent selfing to F10 under field conditions in trials at multiple locations. We characterized the reprogramming of defense-related signaling in these RILs as a consequence of spot blotch attack. During resistance to spot blotch attack, wheat strongly elicits SA signaling (SA biogenesis as well as the NPR1-dependent signaling pathway), along with WRKY33 transcription factor, followed by an enhanced expression of phenylpropanoid pathway genes. These may lead to accumulation of phenolics-based defense metabolites that may render resistance against spot blotch. JA signaling may synergistically contribute to the resistance. Failure to elicit SA (and possibly JA) signaling may lead to susceptibility against spot blotch infection in wheat. © 2016 The Authors. © 2016 John Wiley & Sons Ltd.
Genetic factors affecting photosynthesis
(CRC Press, 2016) A.K. Joshi; Shree P. Pandey
[No abstract available]
Isolation and identification of natural endophytic rhizobia from rice (Oryza sativa L.) through rDNA PCR-RFLP and sequence analysis
(2006) Ramesh K. Singh; Ravi P. N. Mishra; Hemant K. Jaiswal; Vinod Kumar; Shree P. Pandey; Sasi B. Rao; Kannapali Annapurna
Three novel endophytic rhizobial strains (RRE3, RRE5, and RRE6) were isolated from naturally growing surface sterilized rice roots. These isolates had the ability to nodulate common bean (Phaseolus vulgaris). Polymerase chain reaction-restriction fragment length polymorphism and sequencing of 16S rDNA of these isolates revealed that RRE3 and RRE5 are phylogenetically very close to Burkholderia cepacia complex, whereas RRE6 has affinity with Rhizobium leguminosarum bv. phaseoli. Plant infection test using gusA reporter gene tagged construct of these isolates indicated that bacterial cells can go inside and colonize the rice root interiors. A significant increase in biomass and grain yield was also recorded in greenhouse-grown rice plants inoculated with these isolates. © Springer Science+Business Media, Inc. 2006.
Isolation and identification of natural endophytic rhizobia from rice (Oryza sativa L.) through rDNA PCR-RFLP and sequence analysis
(2006) Ramesh K. Singh; Ravi P. N. Mishra; Hemant K. Jaiswal; Vinod Kumar; Shree P. Pandey; Sasi B. Rao; Kannepalli Annapurna
Three novel endophytic rhizobial strains (RRE3, RRE5, and RRE6) were isolated from naturally growing surface-sterilized rice roots. These isolates had the ability to nodulate common bean (Phaseolus vulgaris). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing of 16S rDNA of these isolates revealed that RRE3 and RRE5 are phylogenetically very close to Burkholderia cepacia complex, whereas RRE6 has affinity with Rhizobium leguminosarum bv. phaseoli. Plant infection test using gusA reporter gene-tagged construct of these isolates indicated that bacterial cells can go inside and colonize the rice root interiors. A significant increase in biomass and grain yield was also recorded in greenhouse-grown rice plants inoculated with these isolates. © Springer Science+Business Media, Inc. 2006.
Metabolite profiling identified pipecolic acid as an important component of peanut seed resistance against Aspergillus flavus infection
(Elsevier B.V., 2021) Sandeep Sharma; Babita Choudhary; Sonam Yadav; Avinash Mishra; Vinod K. Mishra; Ramesh Chand; Chen Chen; Shree P. Pandey
In a previous study, we identified a halotolerant rhizobacterium belonging to the genus Klebsiella (MBE02) that protected peanut seeds from Aspergillus flavus infection. Here, we investigated the mechanisms underlying the effect of MBE02 against A. flavus via untargeted metabolite profiling of peanut seeds treated with MBE02, A. flavus, or MBE02+A. flavus. Thirty-five metabolites were differentially accumulated across the three treatments (compared to the control), and the levels of pipecolic acid (Pip) were reduced upon A. flavus treatment only. We validated the function of Pip against A. flavus using multiple resistant and susceptible peanut cultivars. Pip accumulation was strongly associated with the resistant genotypes that also accumulated several mRNAs of the ALD1-like gene in the Pip biosynthesis pathway. Furthermore, exogenous treatment of a susceptible peanut cultivar with Pip reduced A. flavus infection in the seeds. Our findings indicate that Pip is a key component of peanut resistance to A. flavus. © 2020 Elsevier B.V.
Natural variation in elicitation of defense-signaling associates to field resistance against the spot blotch disease in bread wheat (Triticum aestivum L.)
(Frontiers Media S.A., 2018) Sandeep Sharma; Ranabir Sahu; Sudhir Navathe; Vinod K. Mishra; Ramesh Chand; Pawan K. Singh; Arun K. Joshi; Shree P. Pandey
Spot blotch, caused by the hemibiotropic fungus Bipolaris sorokiniana, is amongst the most damaging diseases of wheat. Still, natural variation in expression of biochemical traits that determine field resistance to spot blotch in wheat remain unaddressed. To understand how genotypic variations relate to metabolite profiles of the components of defense-signaling and the plant performance, as well as to discover novel sources of resistance against spot blotch, we have conducted field studies using 968 wheat genotypes at 5 geographical locations in South-Asia in 2 years. 46 genotypes were identified as resistant. Further, in independent confirmatory trials in subsequent 3 years, over 5 geographical locations, we re-characterized 55 genotypes for their resistance (above 46 along with Yangmai#6, a well characterized resistant genotype, and eight susceptible genotypes). We next determined time-dependent spot blotch-induced metabolite profiles of components of defense-signaling as well as levels of enzymatic components of defense pathway (such as salicylic acid (SA), phenolic acids, and redox components), and derived co-variation patterns with respect to resistance in these 55 genotypes. Spot blotch-induced SA accumulation was negatively correlated to disease progression. Amongst phenolic acids, syringic acid was most strongly inversely correlated to disease progression, indicating a defensive function, which was independently confirmed. Thus, exploring natural variation proved extremely useful in determining traits influencing phenotypic plasticity and adaptation to complex environments. Further, by overcoming environmental heterogeneity, our study identifies germplasmand biochemical traits that are deployable for spot blotch resistance in wheat along South-Asia. © 2018 Sharma, Sahu, Navathe, Mishra, Chand, Singh, Joshi and Pandey.