@article { ISI:000344448000015, title = {Anti-fungal potentials of extracellular metabolites of western ghats isolated streptomyces sp NII 1006 against moulds and yeasts}, journal = {Indian Journal of Experimental Biology }, volume = {52}, number = {11}, year = {2014}, month = {NOV}, pages = {1138-1146}, publisher = {NATL INST SCIENCE COMMUNICATION-NISCAIR}, type = {Article}, address = {DR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIA}, abstract = {

Realization of hazardious effects of chemical fungicides has led to an interest in the usage of biocontrol agents. The present study, therefore, evaluates the biocontrol efficacy of Western Ghats (India) soil bacterial isolates. A potential strain NII 1006 was evaluated for its antagonistic property against a diverse range of moulds and yeasts. The strain was characterized morphologically, biochemically and molecularly, which revealed the isolate belonged to Streptomyces genus. Organic solvent extracts of NII 1006 culture filtrates inhibited the growth of the test pathogens indicating that growth suppression was due to extracellular anti-fungal metabolites present in the culture filtrates. The strain produced extracellular chitinase enzyme in addition to some stable partially purified anti-fungal compounds. Morphological changes such as hyphae degradation into debris and abnormal shapes were observed in test fungi and yeast grown on potato dextrose broth that contained the NII 1006 culture filtrate. The cell free supernatant has a tolerance to wide range of pH, temperature and enzymes such as lipase and protease. The biocontrol potential of NII 1006 strain may be correlated significantly with their ability to produce antibiotics as well as extracellular hydrolytic enzymes particularly chitinolytic enzyme.

}, keywords = {Anti-fungal activity, Biocontrol, Extracellular anti-fungal metabolites, Streptomyces}, issn = {0019-5189}, author = {Jayamurthy, Himani and Sajna, Kuttavan Valappil and Dastager, Syed Gulam and Pandey, Ashok} } @article {47161, title = {Potent chitin-hydrolyzing enzyme from Myrothecium verrucaria affects growth and development of Helicoverpa armigera and plant fungal pathogens}, journal = {International Journal of Biological Macromolecules}, volume = {141}, year = {2019}, month = {DEC }, pages = {517-528}, type = {Article}, abstract = {

Chitin, a crucial structural and functional component of insects and fungi, serves as a target for pest management by utilizing novel chitinases. Here, we report the biocontrol potential of recombinant Myrothecium verrucaria endochitinase (rMvEChi) against insect pest and fungal pathogens. A complete ORF of MvEChi (1185 bp) was cloned and heterologously expressed in Escherichia coli. Structure based sequence alignment of MvEChi revealed the presence of conserved domains SXGG and DXXDXDXE specific for GH-18 family, involved in substrate binding and catalysis, respectively. rMvEChi (46.6 kDa) showed optimum pH and temperature as 7.0 and 30 degrees C, respectively. Furthermore, rMvEChi remained stable within the pH range of 6.0 to 8.0 and up to 40 degrees C. rMvEChi exhibited k(cat)/K-m values of 129.83 x 10(3) [(g/L)(-1) s(-1)] towards 4MU chitotrioside. Hydrolysis of chitooligosaccharides with various degrees of polymerization (DP) using rMvEChi indicated the release of DP2 as main end product with order of reaction as DP6 \> DP5 \> DP4 \> DP3. Bioassay of rMvEChi against Helicoverpa armigera displayed potent anti-feedant activity and induced mortality. In vitro antifungal activity against plant pathogenic fungi (Ustilago maydis and Bipolaris sorokiniana) exhibited significant inhibition of mycelium growth. These results suggest that MvEChi has significant potential in enzyme-based pest and pathogen management. (C) 2019 Elsevier B.V. All rights reserved.

}, keywords = {Biocontrol, endochitinase, Myrothecium verrucaria}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2019.09.031}, author = {Vidhate, Ravindra P. and Bhide, Amey J. and Gaikwad, Sushama M. and Giri, Ashok P.} } @article {46153, title = {Puzzle of highly virulent Metarhizium anisopliae strains from Annona squamosa fields against Helicoverpa armigera}, journal = {Journal of Basic Microbiology}, volume = {59}, year = {2019}, month = {APR}, pages = {392-401}, type = {Article}, abstract = {

In our search for indigenous virulent strains of the entomopathogenic fungi, we observed that Metarhizium isolates from soils associated with Annona squamosa (custard apple) have higher virulence (\>90\% mortality of Helicoverpa armigera larvae at 1/10(th) spore concentration) than strains isolated from Solanum lycopersicum (tomato) fields. Proteomic analysis revealed two insecticidal cyclopeptides of A. squamosa origin in the M. anisopliae strains that led to higher virulence against H. armigera. Transcriptomic and genomic data indicated that M. anisopliae strains and A. squamosa had more than 20 genes in common, including those for cyclic hexapeptide synthase, non-ribosomal peptide synthetase, and plant cyclotide genes, which are involved in the biosynthesis of insecticidal cyclopeptides. These genes were absent in M. anisopliae strains isolated from the S. lycopersicum fields. Further, these strains can establish an endophytic relationship with A. squamosa suggesting that these rhizospheric strains originally could be endophytes, which were eventually released into the soil. Further, Metarhizium strains associated with Capsicum annuum (chili), Azadirachta indica (neem), and Carica papaya (papaya) - plants with insecticidal properties - also had higher virulence against H. armigera. Thus exploration of rhizospheres of plants producing insecticidal metabolites to isolate entomopathogenic fungi, per se, could be a viable strategy in agricultural for crop protection.

}, keywords = {Annona squamosa, Biocontrol, endophyte, entomopathogen, Helicoverpa armigera, horizontal gene transfer, insecticidal peptides, Metarhizium, natural transformation}, issn = {0233-111X}, doi = {10.1002/jobm.201800631}, author = {Pathan, Ejaj K. and Deshpande, Mukund V.} } @article {48446, title = {Genomic determinants of entomopathogenic fungi and their involvement in pathogenesis}, journal = {Microbial Ecology}, volume = {85}, year = {2023}, month = {JAN}, pages = {49-60}, type = {Article}, abstract = {

Entomopathogenic fungi offer an effective and eco-friendly alternative to curb insect populations in biocontrol strategy. The evolutionary history of selected entomopathogenic fungi indicates their ancestral relationship with plant endophytes. During this host shifting, entomopathogenic fungi must have acquired multiple mechanisms, including a combination of various biomolecules that make them distinguishable from other fungi. In this review, we focus on understanding various biochemical and molecular mechanisms involved in entomopathogenesis. In particular, we attempt to explain the indispensable role of enlarged gene families of various virulent factors, viz. chitinases, proteases, lipases, specialized metabolites, and cytochrome P450, in entomopathogenesis. Our analysis suggests that entomopathogenic fungi recruit a different set of gene products during the progression of pathogenesis. Knowledge of these bio-molecular interactions between fungi and insect hosts will allow researchers to execute pointed efforts towards the development of improved entomopathogenic fungal strains.

}, keywords = {Biocontrol, Chitinases, Endophytic fungi, Entomopathogenic fungi, Hydrolytic enzymes, Insect pests}, issn = {0095-3628}, doi = {10.1007/s00248-021-01936-z}, author = {Vidhate, Ravindra P. and Dawkar, Vishal V. and Punekar, Sachin A. and Giri, Ashok P.} }