OAR@ICRISATIdentification and Characterization of a Streptomyces albus Strain and Its Secondary Metabolite Organophosphate against Charcoal Rot of SorghumSGopalakrishnanauthorRSharmaauthorVSrinivasauthorNNareshauthorS PMishraauthorSAnkatiauthorSPratyushaauthorMGovindarajauthorS VGonzalezauthorSNervikauthorNSimicauthorStreptomycesalbus strain CAI-21 has been previously reported to have plant growth-promotion abilities in chickpea, pigeonpea, rice, and sorghum. The strain CAI-21 and its secondary metabolite were evaluated for their biocontrol potential against charcoal rot disease in sorghum caused by Macrophomina phaseolina. Results exhibited that CAI-21 significantly inhibited the growth of the pathogen, M. phaseolina, in dual-culture (15 mm; zone of inhibition), metabolite production (74% inhibition), and blotter paper (90% inhibition) assays. When CAI-21 was tested for its biocontrol potential under greenhouse and field conditions following inoculation of M. phaseolina by toothpick method, it significantly reduced the number of internodes infected (75% and 45% less, respectively) and length of infection (75% and 51% less, respectively) over the positive control (only M. phaseolina inoculated) plants. Under greenhouse conditions, scanning electron microscopic analysis showed that the phloem and xylem tissues of the CAI-21-treated shoot samples were intact compared to those of the diseased stem samples. The culture filtrate of the CAI-21 was purified by various chromatographic techniques, and the active compound was identified as “organophosphate” by NMR and MS. The e�cacy of organophosphate was found to inhibit the growth of M. phaseolina in the poisoned food technique. This study indicates that S. albus CAI-21 and its active metabolite organophosphate have the potential to control charcoal rot in sorghum.SorghumPlant Disease2020-12MDPIArticle

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