%O We thank PVS Prasad for his significant contribution in the laboratory, greenhouse,
and field studies.
%K Macrophomina phaseolina, Charcoal rot, Sorghum, Biocontrol, Organophosphate
%A S Gopalakrishnan
%A R Sharma
%A V Srinivas
%A N Naresh
%A S P Mishra
%A S Ankati
%A S Pratyusha
%A M Govindaraj
%A S V Gonzalez
%A S Nervik
%A N Simic
%I MDPI
%V 9
%L icrisat11667
%J Plants (TSI)
%N 12
%P 1-14
%R doi:10.3390/plants9121727
%D 2020
%X Streptomycesalbus 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.
%T Identification and Characterization of a Streptomyces albus Strain and Its Secondary Metabolite Organophosphate against Charcoal Rot of Sorghum