Monday, November 13, 2006 - 10:30 AM
53-3
FUR Regulated Defensive Proteins as Anti Fungal Agents.
Munazza Gull and Dr Fauzia Yusuf. National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, Faisalabad, Pakistan
Although many studies have been conducted to identify the specific traits by which plant growth–promoting rhizobacteria (PGPR) promote plant growth, usually they were limited to studying just one or two of these traits. We selected 85 rhizobacterial isolates and examined them for a wide array of traits associated with biocontrol, rhizobial inhibition, and rhizosphere competence that might increase early plant growth. Bacterial strains were studied for in vitro antibiosis against Rhizoctonia solani using various dual cultural techniques.The bacterial strains were screened for FUR regulated defensive proteins (siderophore) production qualitatively by chrome azurol sulphonate (CAS) agar medium and quantitatively by spectrophotometer.The potential role of defensive proteins in the inhibition of Rhizoctonia solani in relation to iron chelator i.e. FeCl3 was also evaluated. Partial characterization of these defensive proteins was carried out by different biochemical assays, purified by gel electrophoresis and HPLC and identified through ESI-Q-TOF mass spectrometry. Strains were tested for hydrolytic enzymatic activity, ARA activity, IAA production, antibiotic resistance, HCN and volatile and diffusible antibiotic production. Bioantagonistic bacterial strains Mst 8.2 and 3.1.1.C produced two types of FUR regulated defensive proteins with the molecular weight 1416.12 and 1416.23 a.m.u. The preliminary screening of bioantagonistic strains showed that they could be used as biocontrol agents against Rhizoctonia solani and have an excellent potential to be used as biocontrol agents in greenhouses and at the field level.