Biosurfactant from Bacillus sp. A5F Reduces Disease Incidence of Sclerotinia sclerotiorum in Soybean Crop.

The present study was conducted to assess the biocontrol activity of biosurfactants obtained from Bacillus species A5F. The variables significantly influencing the production of biosurfactants under in vitro conditions were further optimized using response surface methodology. Optimal values of selected culture variables, i.e., glucose, soybean oil, and incubation time were 3.5 g l-1, 3.5 ml l-1, and 78 h, respectively, resulting in 2.14-fold enhancement in biosurfactant levels in 5 l fermentor. Identified biosurfactants had a significant effect on chlorophyll content, shoot biomass, number of pods, and seed weight. Biosurfactants also reduced the disease incidence in S. sclerotiorum infected soybean plants and showed antagonistic action against major phytopathogens by disrupting the hyphal cell wall. 16% reduction in ITS gene copy number was observed as compared to control with less non-target effect upon biosurfactant spray on foliar parts of soybean. Thus, the study confirms that biosurfactants from strain A5F can be used as a potent biocontrol agent to control sclerotium wilt on soybean plants.

Prospect of pink pigmented facultative methylotrophs in mitigating abiotic stress and climate change.

Apparently, climate change is observed in form of increased greenhouse gases (CH4 , CO2 , N2 O, CFC), temperature (0.5-1°C), and UV radiations (UV B and UV C). It is affecting every aspect of ecosystem functioning; however, terrestrial crops are the most vulnerable group and crop productivity largely remains a challenge. Due to climate change, seed yield and nutrient depletion are inevitable in future scenarios. To overcome this problem microbial groups that exhibit plant growth promoting attributes and provide protection against environmental stress should be studied. One such group is the pink pigmented facultative methylotrophs (PPFMs) that can induce overall fitness to plants. PPFMs are involved in phosphorous mineralization, siderophore, ACC deaminase, phytohormone production, and assimilation of greenhouse gases. Additionally, these organisms can also resist harmful UV radiations effectively as they possess polyketide synthases that could serve as source of novel bioactives that can protect plant from abiotic stress. The review article comprehensively highlights the multifunctional traits of PPFMs and their role in mitigating climate change with an aim to use this important organism as microbial inoculants for sustainable agriculture under climate-changing scenarios.

Methylotroph bacteria and cellular metabolite carotenoid alleviate ultraviolet radiation-driven abiotic stress in plants.

Increasing UV radiation in the atmosphere due to the depletion of ozone layer is emerging abiotic stress for agriculture. Although plants have evolved to adapt to UV radiation through different mechanisms, but the role of phyllosphere microorganisms in counteracting UV radiation is not well studied. The current experiment was undertaken to evaluate the role of phyllosphere Methylobacteria and its metabolite in the alleviation of abiotic stress rendered by ultraviolet (UV) radiation. A potential pink pigmenting methylotroph bacterium was isolated from the phylloplane of the rice plant (oryzae sativa). The 16S rRNA gene sequence of the bacterium was homologous to the Methylobacter sp. The isolate referred to as Methylobacter sp N39, produced beta-carotene at a rate (µg ml-1 d-1) of 0.45-3.09. Biosynthesis of beta-carotene was stimulated by brief exposure to UV for 10 min per 2 days. Carotenoid biosynthesis was predicted as y = 3.09 × incubation period + 22.151 (r 2 = 0.90). The carotenoid extract of N39 protected E. coli from UV radiation by declining its death rate from 14.67% min-1 to 4.30% min-1 under UV radiation. Application of N39 cells and carotenoid extract also protected rhizobium (Bradyrhizobium japonicum) cells from UV radiation. Scanning electron microscopy indicated that the carotenoid extracts protected E. coli cells from UV radiation. Foliar application of either N39 cells or carotenoid extract enhanced the plant's (Pigeon pea) resistance to UV irradiation. This study highlight that Methylobacter sp N39 and its carotenoid extract can be explored to manage UV radiation stress in agriculture.

Draft Genome Sequence of the Plant Growth-Promoting Rhizobacterium Pseudomonas protegens Strain BNJ-SS-45, Isolated from Rhizosphere Soil of Wheat (Triticum aestivum).

Here, we present the draft genome sequence of Pseudomonas protegens strain BNJ-SS-45, which was isolated from wheat rhizosphere. The genome is assembled with 7,116,445 bp with a GC content of 63.34% consisting of 32 scaffolds. The genome is useful in prediction of secondary metabolites, particularly rhizoxin, pyoverdine, and bacteriocin.