Abstract
Photorhabdus temperata M1021 is an entomopathogenic enterobacterium, producing an array of metabolites in the culture extract. Photorhabdus spp. produced various classes of toxic proteins and secondary metabolites, which generate mortality in a wide range of insects. Aim of present study was to assess the effects these metabolites towards the insect and plants. Intra-hemocoel injections of whole cell and soluble extract caused 100% mortality in Galleria mellonella larvae within 48 h as compare to control. However, the culture filtrate (CF) took 72 h to kill 100 % larvae. In addition, there was no significant (P<0.05) decrease in the rate of larval mortality, injected with CF, treated at 70 degrees C for 30 min as well as with 50 mg/l proteinase-K. Gas chromatography mass spectrometry analysis revealed 23 compounds, among which "trans-Cinnamic acid" and "indole" were the most important for the insecticidal activities and plant growth promotion. The auxin contents quantified through Salkowski's assay were 28 mu g/ml to 30 mu g/ml, insignificantly varied the by the addition of L-tryptophan ranged from 0 g/l to 0.5 g/l. The optimum pH for the auxin production was determined to be pH 7.0. The CF treatment increases significantly (P<0.05) plant growth that attributes e.g. total plant length, chlorophyll content and biomass of both Dongjin-beyo and Waito-Crice plants, in a comparison with control. The findings of this study suggest that the P. temperata M1021 could be an ideal candidate, to be exploited in agriculture as biocontrol agent.