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

abstract

  • A total of 360 bacteria, isolated from the rhizospheres of a system of riceintensification (SRI) fields, were characterized for the production of siderophore,fluorescence, indole acetic acid (IAA), hydrocyanic acid (HCN) and solubilization ofphosphorus. Of them, seven most promising isolates (SRI-156, -158, -178, -211, -229, -305and -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 isolatessolubilized phosphorous (except SRI-360), all seven produced siderophore, four producedfluorescence (except SRI-178, -229 and -305), six produced IAA (except SRI-305) and fiveproduced HCN (except SRI-158 and -305). In the blotter paper assay, no charcoal rotinfection was observed in SRI-156-treated sorghum roots, indicating complete inhibition ofthe pathogen, while the roots treated with the other isolates showed 49?76% lesser charcoalrot infection compared to the control. In the antifungal activity test (in green house onsorghum), all the isolates increased shoot dry mass by 15?23% and root dry mass by15?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 theabsence of M. phaseolina. The results further confirmed the PGP traits of the isolates asevidenced by increases in shoot and root dry mass, 22?100% and 5?20%, respectively, overthe control. The sequences of 16S rDNA gene of the isolates SRI-156, -158, -178, -211, -229,-305 and -360 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 bacterialisolates have the potential for PGP and control of charcoal rot disease in sorghum

publication date

  • 2011
  • 2011