Deciphering the potential of Sargassum tenerrimum extract: metabolic profiling and pathway analysis of groundnut (Arachis hypogaea) in response to Sargassum extract and Sclerotium rolfsii.

Seaweed extracts have enormous potential as bio-stimulants and demonstrated increased growth and yield in different crops. The presence of physiologically active component stimulate plant stress signaling pathways, enhances growth and productivity, as well as serve as plant defense agents. The seaweed extracts can reduce the use of chemicals that harm the environment for disease management. In the present study, the Sargassum tenerrimum extract treatment was applied, alone and in combination with Sclerotium rolfsii, to Arachis hypogea, to study the differential metabolite expression. The majority of metabolites showed maximum accumulation with Sargassum extract-treated plants compared to fungus-treated plants. The different classes of metabolite compounds like sugars, carboxylic acids, polyols, showed integrated peaks in different treatments of plants. The sugars were higher in Sargassum extract and Sargassum extract + fungus treatments compared to control and fungus treatment, respectively. Interestingly, Sargassum extract + fungus treatment showed maximum accumulation of carboxylic acids. Pathway enrichment analysis showed regulation of different metabolites, highest impact with galactose metabolism pathway, identifying sucrose, myo-inositol, glycerol and fructose. The differential metabolite profiling and pathway analysis of groundnut in response to Sargassum extract and S. rolfsii help in understanding the groundnut- S. rolfsii interactions and the potential role of the Sargassum extract towards these interactions. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-024-01418-9.

Comparative transcriptome analysis elucidates positive physiological effects of foliar application of pyraclostrobin on tomato (Solanum lycopersicum L.).

Strobilurins, including pyraclostrobin have frequently been reported showing positive physiological effects in various agricultural crops apart from fungicidal activity. Present study elucidates comparative transcriptome analysis of control and pyraclostrobin treated tomato leaf and identifies metabolic pathways and key genes responsible for positive effects of pyraclostrobin on tomato. Pair-end raw reads, generated by Illumina Hi-seq platform were pre-processed and good quality reads were mapped onto tomato reference genome using HISAT2 alignment programme. Transcript assembly and quantification were performed using StringTie assembler. Differential Gene Expression analysis by DESeq2 identified 1,952 upregulated genes including genes encoding pathogenesis related proteins and 835 downregulated genes. RT-PCR study showed increase in expression of RBCs (2.5-fold), GA20o (3-fold), and NR (1.4-fold) genes, which are the key genes of photosynthesis, gibberellic acid synthesis, and nitrogen assimilation pathways respectively identified in KEGG pathway analysis. Pyraclostrobin treated plants showed 1.6-folds increase in plant height, 3.3-folds increase in number of leaves, and 2.8-folds increase in number of flowers. Total protein content increased 1.7, 1.4, 1.2, 1.2, and 1.4 folds at 1 day after application (DAA), 4DAA, 7DAA, 10DAA, and 13DAA respectively in treated plants. Moreover, content of phenol also increased 1.14, 1.5, 2.4, and 1.5 folds in 4DAA, 7DAA, 10DAA, and 13DAA respectively. Nitrate reductase activity increased 2-fold, 1.8-fold, 1.5-fold and 1.15-fold in 1DAA, 7DAA, 10DAA and 13DAA respectively. Carbohydrate decreased in treated plants up to 7DAA. The present study is the first report of transcriptome analysis elucidating positive physiological effects of strobilurin on plant. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01191-7.

Improved live-cell PCR method for detection of organophosphates degrading opd genes and applications.

Organophosphates are becoming an emerging pollutant due to their various applications, particularly as pesticides. In this study, an improved Colony (Live-cell) PCR method was developed for the detection of opd genes from bacteria encoding the organophosphate hydrolase enzymes capable of degrading various organophosphates. The improved method does not require pre-heating or pre-lysis of bacterial cells as essential in the conventional colony PCR. The reaction volume was scaled down to 10 µl by optimizing the PCR buffer and amplification conditions. The improved method was used for Gram positive and negative bacteria, glycerol stocks, liquid cultures, recombinant and mutant strains. Also, 16S rRNA gene was amplified from unknown environmental isolates and known E. coli strains. The amplified opd and 16S rRNA genes from the improved colony PCR method and by conventional PCR were sequenced, and similar results were obtained from both techniques. Thus, the improved method can be further explored in molecular biology or during biomarker studies. KEY POINTS: • Improved colony PCR method was developed for screening of opd genes from bacteria. • Method was validated for Gram positive/negative bacteria from solid as well as liquid media. • The improved method was rapid, efficient, and can be applied under various conditions.