PubMed | Indian Institute of Science, ICAR Directorate of Seed Research, Integral University, Narendra Dev University of Agriculture and Technology and 3 more.
Type: | Journal: Microbiological research | Year: 2016
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.
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.)
Singh U.B.,Integral University |
Malviya D.,ICAR National Bureau of Agriculturally Important Microorganisms |
Wasiullah,ICAR National Bureau of Agriculturally Important Microorganisms |
Singh S.,ICAR National Bureau of Agriculturally Important Microorganisms |
And 8 more authors.
Applied Soil Ecology | Year: 2016
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.
Kashyap P.L.,ICAR Indian Institute of Wheat and Barley Research IIWBR |
Kumar S.,ICAR Indian Institute of Wheat and Barley Research IIWBR |
Srivastava A.K.,ICAR National Bureau of Agriculturally Important Microorganisms
Environmental Chemistry Letters | Year: 2016
Rapid detection technologies with high sensitivity and selectivity for plant pathogens are essential to prevent disease spread and minimize losses to assure optimal productivity and food security. Traditional laboratory techniques such as microscopy and culture are time-consuming, labour intensive and require complex sample handling. Immunological and molecular techniques have advanced but have some issues related to rapidity, signal strength and instrumentation. The integration of immunological and molecular diagnostics with nanotechnology systems offers an option where all detection steps can be accommodated on a portable miniaturized device for rapid and accurate detection of plant pathogens. The sensitive nature of functionalized nanoparticles can be used to design phytopathogen detection devices with smart sensing capabilities for field use. This review summarizes the current status and future prospects of nanotechnology for detection and diagnosis of plant pathogens. © 2016 Springer International Publishing Switzerland
PubMed | ICAR National Bureau of Agriculturally Important Microorganisms
Type: Journal Article | Journal: Journal of basic microbiology | Year: 2016
Penicilliopsis clavariiformis AP, a rare salt tolerant fungus reported for the first time from India was identified through polyphasic taxonomy. Scanning electron microscopy showed that the fungus has unique features such as biverticillate penicilli bearing masses of oval to ellipsoidal conidia. The fungus has been characterized for salt tolerance and to understand the relevance of central carbon metabolism in salt stress adaptation. It showed optimal growth at 24C and able to tolerate up to 10% (w/v) NaCl. To understand the mechanism of adaptation to high salinity, activities of the key enzymes regulating glycolysis, pentose phosphate pathway, and tricarboxylic acid cycle were investigated under normal (0% NaCl) and saline stress environment (10% NaCl). The results revealed a re-routing of carbon metabolism away from glycolysis to the pentose phosphate pathway (PPP), served as a cellular stress-resistance mechanism in fungi under saline environment. The detection and significant expression of fungus genes (Hsp98, Hsp60, HTB, and RHO) under saline stress suggest that these halotolerance conferring genes from the fungus could have a role in fungus protection and adaptation under saline environment. Overall, the present findings indicate that the rearrangement of the metabolic fluxes distribution and stress related genes play an important role in cell survival and adaptation under saline environment.