Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of cotton seedlings due to F. oxysporum infection. SVI values of 30 day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillus subtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis.

Objective: To investigate the antioxidant activity of methanolic extract of endophytic fungi isolated from Calotropis procera plant. Methods:The endophytic fungi were isolated from explants of leaf, stem, and flower of C. procera on potato dextrose broth (PDB) medium. The fungal isolates were mass cultured in PDB. The methanolic extracts of these fungi were prepared and evaluated for the antioxidant activity by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay and reducing power assay. The extracts were characterized for the presence of phenolics and flavonoids.Results: A total of 8 endophytic fungi were isolated from C. procera explants. Out of these 8 fungal isolates, the crude extracts of two fungi, i.e. CPIMR-2 and CPIL-1 showed positive antioxidant activity. From the morphological characteristics, the isolates CPIMR-2 and CPIL-1 were identified as Penicillium spp. and Aspergillus spp., respectively. Both the isolates were found to possess antioxidant potential with % inhibition value of 81.16% and 80.97% in the DPPH radical scavenging assay. The phytochemical screening of the methanolic extracts showed the presence of phenolics and flavonoids. The total flavonoids content in Penicillium species and Aspergillus species were found to be 130.50 µg/mg and 94.91 µg/mg of extracts, respectively. The total phenolic content was found to be 9.16 µg/mg and 12.13 µg/mg of extracts in Penicillium species and Aspergillus species, respectively. Conclusions:Endophtyic fungi were found to be present in medicinal value plant C. procera. The probable bioactive component for antioxidant activity possessed by the fungi would be the flavonoids and phenolics. These metabolite produced by endophytic fungi from C. procera need to be explored further as potential source of novel natural antioxidant compound.

Use of green compounds to achieve the sustainable agriculture is the present necessity. Biosurfactants are one of the green compounds reported to be produced by bacteria, yeasts, and fungi which are considered to be less toxic and eco-friendly with extensive applications in pharmaceutical, cosmetics, and food industries. Bacillus group is one of the examples of biosurfactant producers. In the present study, soil isolates of Bacillus species were screened for the production of biosurfactant by oil spread assay. The activity was found positive in three isolates which were assayed for antifungal activity against the phytopathogens R. oryzae-sativae and F. solani. The biocontrol activity was observed in both extracellular and the homogenized biomass fractions of B. subtilis BP-9, B. subtilis BP-13 and Bacillus isolate PRIS-1. Different methods as acid precipitation, organic solvent extraction and salting out by ammonium sulfate were used for isolation of biosurfactant lipoeptides from the extracellular fractions of B. subtilis BP-9, B. subtilis BP-13 and Bacillus species PRIS-1. The antifungal as well as biosurfactant property was confirmed in the acid precipitated fraction of Bacillus isolate PRIS-1. The compound was identified as a high molecular weight protein by SDS-PAGE with approximate size of 100kD.

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