Browsing by Author "Wasiullah"

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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
Bioremediation of heavy metals from soil and aquatic environment: An overview of principles and criteria of fundamental processes
(MDPI, 2015) Ruchita Dixit; Wasiullah; Deepti Malaviya; Kuppusamy Pandiyan; Udai B. Singh; Asha Sahu; Renu Shukla; Bhanu P. Singh; Jai P. Rai; Pawan Kumar Sharma; Harshad Lade; Diby Paul
Heavy metals are natural constituents of the environment, but indiscriminate use for human purposes has altered their geochemical cycles and biochemical balance. This results in excess release of heavy metals such as cadmium, copper, lead, nickel, zinc etc. into natural resources like the soil and aquatic environments. Prolonged exposure and higher accumulation of such heavy metals can have deleterious health effects on human life and aquatic biota. The role of microorganisms and plants in biotransformation of heavy metals into nontoxic forms is well-documented, and understanding the molecular mechanism of metal accumulation has numerous biotechnological implications for bioremediation of metal-contaminated sites. In view of this, the present review investigates the abilities of microorganisms and plants in terms of tolerance and degradation of heavy metals. Also, advances in bioremediation technologies and strategies to explore these immense and valuable biological resources for bioremediation are discussed. An assessment of the current status of technology deployment and suggestions for future bioremediation research has also been included. Finally, there is a discussion of the genetic and molecular basis of metal tolerance in microbes, with special reference to the genomics of heavy metal accumulator plants and the identification of functional genes involved in tolerance and detoxification. © 2015 by the authors.
Compatible salt-tolerant rhizosphere microbe-mediated induction of phenylpropanoid cascade and induced systemic responses against Bipolaris sorokiniana (Sacc.) Shoemaker causing spot blotch disease in wheat (Triticum aestivum L.)
(Elsevier B.V., 2016) Udai B. Singh; Deepti Malviya; Wasiullah; Shailendra Singh; Mohd. Imran; Neelam Pathak; Manzar Alam; Jai P. Rai; Rajiv K. Singh; B.K. Sarma; P.K. Sharma; Arun K. Sharma
Cell wall is one of the first lines of defence used by plants to restrict invading fungal pathogens. Lignin is a complex polymer of hydroxylated and methoxylated phenylpropane units (monolignols). Cell wall lignification can establish mechanical barriers to pathogen invasion and renders the cell wall more resistant to pathogen attack. Compatible salt-tolerant rhizosphere microbe-mediated induction of phenylpropanoid cascade and induced systemic responses against Bipolaris sorokiniana (Sacc.) Shoemaker causing spot blotch disease in wheat (Triticum aestivum L.) is demonstrated and the details are being shared through this paper. Twelve rhizospheric microbial strains were tested against Bipolaris sorokiniana under in vitro condition on dual plate. Bacillus amyloliquefaciens B-16 and Trichoderma harzianum UBSTH-501 showed maximum inhibition of mycelial growth of B. sorokiniana and was used in further in planta assay. These selected antagonists were tested alone and in combination for induction of phenylpropanoid cascade in wheat infected with B. sorokiniana. Results showed that plants co-inoculated with B. amyloliquefaciens B-16 and T. harzianum UBSTH-501 up-regulated the phenylpropanoid cascade and manifold increase was recorded in phenylalanine ammonia lyase (PAL), peroxidase, chitinase and other enzymes related to induced systemic resistance. Results also showed that significantly higher amounts of phenolic acids viz. gallic acid, ferulic acid were accumulated in the plant leaves co-inoculated with B. amyloliquefaciens B-16 and T. harzianum UBSTH-501 as compared to individually inoculated and uninoculated control plants. Histopathological studies showed significantly higher cell wall lignification in plant leaves co-inoculated with B. amyloliquefaciens B-16 and T. harzianum UBSTH-501 than the plants under control. These results illustrate that microbe-mediated up-regulation of phenylpropanoid biosynthesis pathway is of critical importance for host defence against spot blotch pathogen invasion in wheat. © 2016 Elsevier B.V.