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Rice sheath blight pathogen, Rhizoctonia solani, produces numerous sclerotia to overwinter. As a rich source of nutrients in the soil, sclerotia may lead to the change of soil microbiota. For this purpose, we amended the sclerotia of R. solani in soil and analyzed the changes in bacterial microbiota within the soil at different time points. At the phyla level, Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chloroflexi and Firmicutes showed varied abundance in the amended soil samples compared to those in the control. An increased abundance of ammonia-oxidizing bacterium (AOB) Nitrosospira and Nitrite oxidizing bacteria (NOB) i.e., Nitrospira was observed, where the latter is reportedly involved in the nitrifier denitrification. Moreover, Thiobacillus, Gemmatimonas, Anaeromyxobacter and Geobacter, the vital players in denitrification, N2O reduction and reductive nitrogen transformation, respectively, depicted enhanced abundance in R. solani sclerotia-amended samples. Furthermore, asymbiotic nitrogen-fixing bacteria, notably, Azotobacter as well as Microvirga and Phenylobacterium with nitrogen-fixing potential also enriched in the amended samples compared to the control. Plant growth promoting bacteria, such as Kribbella, Chitinophaga and Flavisolibacter also enriched in the sclerotia-amended soil. As per our knowledge, this study is of its kind where pathogenic fungal sclerotia activated microbes with a potential role in N transformation and provided clues about the ecological functions of R. solani sclerotia on the stimulation of bacterial genera involved in different processes of N-cycle within the soil in the absence of host plants.

Bitter gourd is of great importance due to its usage against the treatment of numerous ailments in human beings. A comprehensive survey at four localities of Southern Punjab, Pakistan was carried out to determine the severity of Myrothecium leaf spot. Maximum disease severity was at C1 (Chak 11/NP) and least at C2 (Kot Mehtab). Among isolated species Myrothecium roridum was found more prevalent and pathogenic as compared to M. verrucaria. Antifungal activity using solvent extracts of five medicinal plants (Mangifera indica, Melia azedarach, Nicotiana tabacum, Moringa oleifera and Eucalyptus globosum) were evaluated against isolated species by agar well diffusion method at various concentrations (0.01, 0.10, 1.0 and 10.0 µg / mL). N. tabacum revealed maximum zone size (13.40 mm and 8.28 mm) with ethanol and chloroform solvents respectively followed by M. azedarach (9.00mm and 6.48mm). However, least inhibition was observed with ethanol and chloroform extracts of E. globosum (6.04mm and 3.88mm zone size respectively). Ethanol extracts showed highest activity when compared to chloroform extracts. Qualitative phytochemical analysis showed that all the selected plants are rich in chemical compounds such as alkaloids, terpenoids, flavonoids and phenols whereas Saponins was only present in N. tabacum while absent in rest of the extracts.