Evaluation of bacteria isolated from rice rhizosphere for biological control of charcoal rot of sorghum caused by Macrophomina phaseolina (Tassi) Goid.

Abstract

A total of 360 bacteria, isolated from the rhizospheres of a system of rice intensification (SRI) fields, were characterized for the production of siderophore, fluorescence, indole acetic acid (IAA), hydrocyanic acid (HCN) and solubilization of phosphorus. Of them, seven most promising isolates and -360) were screened for their antagonistic potential against Macrophomina phaseolina (causes charcoal rot in sorghum) by dual culture assay, blotter paper assay and in greenhouse.All the seven isolates inhibited M. phaseolina in dual culture assay, whereas six isolates solubilized phosphorous (except SRI-360), all seven produced siderophore, four produced fluorescence (except SRI-178, -229 and -305), six produced IAA (except SRI-305) and five produced HCN (except SRI-158 and -305). In the blotter paper assay, no charcoal rot infection was observed in SRI-156-treated sorghum roots, indicating complete inhibition of the pathogen, while the roots treated with the other isolates showed 49−76% lesser charcoal rot infection compared to the control. In the antifungal activity test (in green house on sorghum), all the isolates increased shoot dry mass by 15−23% and root dry mass by 15−20% (except SRI-158 and -360), over the control. In order to confirm the plant growthpromoting (PGP) traits of the isolates, the green house experiment was repeated but, in the absence of M. phaseolina. The results further confirmed the PGP traits of the isolates as evidenced by increases in shoot and root dry mass, 22−100% and 5−20%, respectively, over the control. The sequences of 16S rDNA gene of the isolates were matched with Pseudomonas plecoglossicida, Brevibacterium antiquum, Bacillus altitudinis, Enterobacter ludwigii, E. ludwigii, Acinetobacter tandoii and P. monteilii, respectively in BLAST analysis. This study indicates that the selected bacterial isolates have the potential for PGP and control of charcoal rot disease in sorghum.3

Isolation and characterization of Bacillus altitudinis JSCX-1 as a new potential biocontrol agent against Phytophthora sojae in soybean [Glycine max (L.) Merr.]

“…1). Recently, reports of B. altitudinis having the ability to promote growth and suppress root fungal pathogens, such as Macrophomina phaseolina and Thanatephorus cucumeris, were described (Gopalakrishnan et al 2011;Sunar et al 2015), indicating that B. altitudinis was a promising BCA for controlling fungal diseases. In our study, B. altitudinis JSCX-1 showed significant biocontrol activity in in vivo and in vitro assays (Figs.…”

Evaluation ofStreptomycesspp. for their plant-growth-promotion traits in rice

“…The mechanism by which the Streptomyces strains enhanced morphological and yield traits of rice could be attributed to their enzymatic activities such as IAA and siderophore (direct stimulation of PGP) and/or chitinase, protease, hydrocyanic acid, cellulase, lipase and β-1,3-glucanase production capabilities (indirect stimulation of PGP; Gopalakrishnan et al 2011b). The influence of microorganisms on PGP including the root development of the plants has been reported by Birkhofer et al (2008), Uphoff et al (2009) and Gopalakrishnan et al (2011aGopalakrishnan et al ( , b, 2012a. Though the SRI method of rice cultivation supports the growth of PGP microbes (including phosphate solubilizing bacteria, diazotrophs, Azospirillium and Azotobacter) and microbial enzyme activities (Turner and Haygarth 2001;Gayathry 2002) such enhanced activities were found, in the present investigation, only in the Streptomycesinoculated treatments.…”

Antagonistic Evaluation of Bioactive Metabolite from Endophytic Fungus, Aspergillus flavipes KF671231

“…Primary screening for antagonism was done by a confrontation assay [7]. The endophyte and the pathogenic fungus (Sclerotinia sclerotiorum) were cocultured on 90 mm petri dish containing PDA and incubated at 28 ∘ C for 3-5 days to check the interaction between them.…”