Metabolic profiles of peanut (Arachis hypogaea L.) in response to Puccinia arachidis fungal infection.

Background Puccinia arachidis fungus causes rust disease in the peanut plants (Arachis hypogaea L.), which leads to high yield loss. Metabolomic profiling of Arachis hypogaea was performed to identify the pathogen-induced production of metabolites involved in the defense mechanism of peanut plants. In this study, two peanut genotypes, one susceptible (JL-24) and one resistant (GPBD-4) were inoculated with Puccinia arachidis fungal pathogen. The metabolic response was assessed at the control stage (0 day without inoculation), 2 DAI (Day after inoculation), 4 DAI and 6 DAI by Gas Chromatography-Mass Spectrometry (GC-MS). Results About 61 metabolites were identified by NIST library, comprising sugars, phenols, fatty acids, carboxylic acids and sugar alcohols. Sugars and fatty acids were predominant in leaf extracts compared to other metabolites. Concentration of different metabolites such as salicylic acid, mannitol, flavonoid, 9,12-octadecadienoic acid, linolenic acid and glucopyranoside were higher in resistant genotype than in susceptible genotype during infection. Systemic acquired resistance (SAR) and hypersensitive reaction (HR) components such as oxalic acid was elevated in resistant genotype during pathogen infection. Partial least square-discriminant analysis (PLS-DA) was applied to GC-MS data for revealing metabolites profile between resistant and susceptible genotype during infection. Conclusion The phenol content and oxidative enzyme activity i.e. catalase, peroxidase and polyphenol oxidase were found to be very high at 4 DAI in resistant genotype (p-value < 0.01). This metabolic approach provides information about bioactive plant metabolites and their application in crop protection and marker-assisted plant breeding.

Comparative assessment of soil microbial community in crude oil contaminated sites.

Petroleum refineries generate oily sludge that contains hazardous polycyclic aromatic hydrocarbons (PAH), and hence, its proper disposal is of foremost concern. Analysis of the physicochemical properties and functions of indigenous microbes of the contaminated sites are essential in deciding the strategy for bioremediation. This study analyses both parameters at two geographically distant sites, with different crude oil sources, and compares the metabolic capability of soil bacteria with reference to different contamination sources and the age of the contaminated site. The results indicate that organic carbon and total nitrogen derived from petroleum hydrocarbon negatively affect microbial diversity. Contamination levels vary widely on site, with levels of PAHs ranging from 5.04 to 1.66 × 103 µg kg-1 and 6.20 to 5.64 × 103 µg kg-1 in Assam and Gujarat sites respectively, covering a higher proportion of low molecular weight (LMW) PAHs (fluorene, phenanthrene, pyrene, and anthracene). Functional diversity values were observed to be positively correlated (p < 0.05) with acenaphthylene, fluorene, anthracene, and phenanthrene. Microbial diversity was the highest in fresh oily sludge which decreased upon storage, indicating that immediate bioremediation, soon after its generation, would be beneficial. Improvement in the bio-accessibility of hydrocarbon compounds by the treatment of biosurfactant produced by a (soil isolate/isolate) was demonstrated., with respect to substrate utilization.

Comparative RNA-Seq profiling of a resistant and susceptible peanut (Arachis hypogaea) genotypes in response to leaf rust infection caused by Puccinia arachidis.

The goal of this study was to identify differentially expressed genes (DEGs) responsible for peanut plant (Arachis hypogaea) defence against Puccinia arachidis (causative agent of rust disease). Genes were identified using a high-throughput RNA-sequencing strategy. In total, 86,380,930 reads were generated from RNA-Seq data of two peanut genotypes, JL-24 (susceptible), and GPBD-4 (resistant). Gene Ontology (GO) and KEGG analysis of DEGs revealed essential genes and their pathways responsible for defence response to P. arachidis. DEGs uniquely upregulated in resistant genotype included pathogenesis-related (PR) proteins, MLO such as protein, ethylene-responsive factor, thaumatin, and F-box, whereas, other genes down-regulated in susceptible genotype were Caffeate O-methyltransferase, beta-glucosidase, and transcription factors (WRKY, bZIP, MYB). Moreover, various genes, such as Chitinase, Cytochrome P450, Glutathione S-transferase, and R genes such as NBS-LRR were highly up-regulated in the resistant genotype, indicating their involvement in the plant defence mechanism. RNA-Seq analysis data were validated by RT-qPCR using 15 primer sets derived from DEGs producing high correlation value (R 2 = 0.82). A total of 4511 EST-SSRs were identified from the unigenes, which can be useful in evaluating genetic diversity among genotypes, QTL mapping, and plant variety improvement through marker-assisted breeding. These findings will help to understand the molecular defence mechanisms of the peanut plant in response to P. arachidis infection.

Uncloaking lncRNA-meditated gene expression as a potential regulator of CMS in cotton (Gossypium hirsutum L.).

Cytoplasmic male sterility is a well-proven mechanism for cotton hybrid production. Long non-coding RNAs belong to a class of transcriptional regulators that function in multiple biological processes. The cDNA libraries from the flower buds of the cotton CGMS, it's restorer (Rf) and maintainer lines were sequenced using high throughput NGS technique. A total of 1531 lncRNAs showed significant differential expression patterns between these three lines. Functional analysis of the co-expression network of lncRNA-mRNA using gene ontology vouchsafes that, lncRNAs play a crucial role in cytoplasmic male sterility and fertility restoration through pollen development, INO80 complex, development of anther wall tapetum, chromatin remodeling, and histone modification. Additionally, 94 lncRNAs were identified as putative precursors of 49 miRNAs. qRT-PCR affirms the concordance of expression pattern to RNA-seq data. These findings divulge the lncRNA driven miRNA-mediated regulation of gene expression profiling superintended for a better understanding of the CMS mechanisms of cotton.

Draft Genome Sequence of the Endophytic Bacterium Enterobacter spp. MR1, Isolated from Drought Tolerant Plant (Butea monosperma).

Enterobacter sp. MR1 an endophytic plant growth promoting bacterium was isolated from the roots of Butea monosperma, a drought tolerant plant. Genome sequencing of Enterobacter spp. MR1 was carried out in Ion Torrent (PGM), Next Generation Sequencer. The data obtained revealed 640 contigs with genome size of 4.58 Mb and G+C content of 52.8 %. This bacterium may contain genes responsible for inducing drought tolerance in plant, including genes for phosphate solubilization, growth hormones and other useful genes for plant growth.

Draft Genome Sequence of the Methyl Parathion (Pesticide) Degrading Bacterium Pseudomonas spp. MR3.

Pseudomonas spp. MR3 was isolated from the surrounding soil of pesticide manufacturing industries of Ankleshwar, Gujarat. Under laboratory conditions these microbes were able to degrade up to 500 ppm of methyl parathion within 72 h. Genome sequencing of Pseudomonas spp. MR3 was carried out inIon Torrent (PGM), next generation sequencer. The data obtained revealed 1,268 contigs with genome size of 2.99 Mb and G + C content of 60.9 %. The draft genome sequence of strain MR3 will be helpful in studying the genetic pathways involved in the degradation of several pesticides.