Genome mining
of secondary metabolites from Streptomyces spp. for the screening of novel and potent
fungicide: Focus on rice blast disease
Ajitha Antony, Varsini Sakthi, Shanthi Veerappapillai and Ramanathan Karuppasamy
Res. J. Chem. Environ.; Vol. 29(10); 66-75;
doi: https://doi.org/10.25303/2910rjce066075; (2025)
Abstract
Rice stands as the most consumed commodity globally, serving as the primary energy
source for nearly half of the world's population. However, rice blast disease, caused
by the fungus Magnaporthe oryzae, leads to significant production losses. This research
focuses on devising a sustainable solution against M. oryzae using advanced computational
techniques including genome mining and in silico screening. The melanin pathway
in M. oryzae involving the conversion of tyrosine to melanin is crucial for its
pathogenicity. Succinate dehydrogenase (SDH) plays a key role in this pathway by
catalysing the oxidation of succinate to fumarate, thereby contributing to the production
of melanin. Currently, carpropamid is used as a commercial inhibitor for rice blast
disease due to its broad-spectrum fungicidal activity. However, its unintended harm
to non-target organisms presents limitations, highlighting the need for alternative
solutions to combat rice blast disease.
Streptomyces-derived bio-fungicides emerge as a promising alternative, harnessing
bioactive chemicals produced by plant endophytic bacteria to suppress pathogen growth.
The research leveraged genome mining from the 23 whole genome sequence of plant
endophytic streptomyces. This process yielded 3343 putative molecules and further
reduced to 906 compounds after removing duplicates. These compounds were subjected
to a series of molecular simulation strategy to unveil the potent fungicide compound.
Ultimately, the study identifies Cremeomycin and Azetidomonamide B as secondary
metabolites with superior binding affinity, interaction and fungicidal potential
compared to carpropamid. The future trajectory of this research entails experimental
validation and the development of sustainable bio-fungicides against rice blast
disease.
