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Isolation and characterization of secondary metabolites of actinomycetes against plant pathogens of chickpea and sorghum. *Gottumukkala Alekhya and S. Gopalakrishnan. INTRODUCTION
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Isolation and characterization of secondary metabolites of actinomycetes against plant pathogens of chickpea and sorghum *Gottumukkala Alekhya and S. Gopalakrishnan INTRODUCTION Actinomycetes are known to have plant growth promoting traits and antagonistic activity against plant pathogens. The objective of the present experiment is to isolate the promising strains of actinomycetes against pathogenic fungi and to isolate the metabolites responsible for it. The fungal pathogens studied include Sclerotium rolfsii, Rhizoctonia bataticola (three strains viz. RB-6, -24 and -115) Fusarium oxysporum f. sp. ciceri, Botrytiscinerea, and Macrophomina phaseolina causes collar rot, dry root rot, Fusarium wilt, Botrytis grey mould diseases in chick pea and charcoal rot in sorghum, respectively. Botrytis grey mould Fusarium wilt Dry root rot Charcoal rot Collar rot Fungal diseases of chickpea and sorghum Actinomycetes cultures showing inhibition METHODOLOGY • Isolation of actinomycetes from ICRISAT SRI rice field • Antagonistic activity of actinomycetes against plant pathogens were tested by Duel Culture Assay • Effect of the culture filtrates of actinomycetes on fungal pathogens were done • The PGPR traits of the antagonistic actinomycetes were studied by using different selective media. • The physiological and morphological properties of the potential actinomycetes were studied. SRI CONT BCA 696 Inhibiting RB6 BCA 696 inhibiting FOC Duel plate assay BCA 696 inhibiting Rb115 CAI 133 inhibiting Fm 242 Antagonistic activity of culture filtrates against fungal pathogens Actinomycetes cultures showing inhibition CONCLUSION A total of 45 actinomycetes were isolated from SRI fields Among 45 actinomycete isolates screened 16 isolates showed broad spectrum anti fungal activity. In the culture filtrate assay, six actinomycetes showed broad spectrum inhibition at 10% filtrate. The potential antagonistic actinomycetes showed PGPR traits which includes chitinase activity, HCN production, lipase activity, protease activity, cellulase, IAA production and Siderophore activity. The duel plate assay and culture filtrate bioassay results showed difference which should be further studied, as some of the cultures showing good results in DPA failed to inhibit in the form of culture filterates. Further the metabolites of the positive cultures should be studied to isolate the most promising compound. The amount of chemical fungicide used against fungal pathogen should be reduced by supplementing with positive actinomycetes cultures BCA 667 inhibiting different fungal pathogens FUTURE WORK Tests have to be done to reduce the amount of chemical fungicide used normally by supplementing with positive actinomycetes cultures. Isolation and purification of metabolites of actinomycetes and to check their antagonistic activity against plant pathogens *Corresponding author G.Alekhya, Email: alekhya.chinnu@gmail.com