Differential gene expression in irradiated potato tubers contributed to sprout inhibition and quality retention during a commercial scale storage.

Current study is the first ever storage cum market trial of radiation processed (28 tons) of potato conducted in India at a commercial scale. The objective was to affirm the efficacy of very low dose of gamma radiation processing of potato for extended storage with retained quality and to understand the plausible mechanism at the gene modulation level for suppression of potato sprouting. Genes pertaining to abscisic acid (ABA) biosynthesis were upregulated whereas its catabolism was downregulated in irradiated potatoes. Additionally, genes related to auxin buildup were downregulated in irradiated potatoes. The change in the endogenous phytohormone contents in irradiated potato with respect to the control were found to be correlated well with the differential expression level of certain related genes. Irradiated potatoes showed retention of processing attributes including cooking and chip-making qualities, which could be attributed to the elevated expression of invertase inhibitor in these tubers. Further, quality retention in radiation treated potatoes may also be related to inhibition in the physiological changes due to sprout inhibition. Ecological and economical analysis of national and global data showed that successful adoption of radiation processing may gradually replace sprout suppressants like isopropyl N-(3-chlorophenyl) carbamate (CIPC), known to leave residue in the commodity, stabilize the wholesale annual market price, and provide a boost to the industries involved in product manufacturing.

Programmed cell death in Xanthomonas axonopodis pv. glycines is associated with modulation of gene expression resulting in altered states of motility, biofilm and virulence.

One of the foremost report of apoptosis-like programmed cell death (PCD) came from Xanthomonas axonopodis pv. glycines (Xag), which displayed rapid post-exponential cell death in PCD inducing media (PIM) but not in a non-inducing media (PNIM). The current study aims to decipher for the first time, the advantages of the existence of PCD in this phytopathogenic microorganism. Analysis of RNA-seq under inducing and non-inducing conditions, revealed differential expression of a number of genes related to key physiology of Xag, such as, motility, xanthan biosynthesis and export as well as virulence. A PCD negative mutant Xag M42 displayed diminished virulence and a contrasting transcriptome pattern. In vitro experiments revealed that under PCD inducing condition, Xag produced negligible xanthan gum as well as extracellular amylase, displayed enhanced swarming motility, released copious e-DNA and formed scanty biofilm. Lack of 'diffusible signalling factor' production was eliminated as possible reason for PCD-induction. Altogether, it appears that, in planta existence of the pathogen metabolically resembles PNIM, and on being transferred to PIM, the cells experience oxidative stress and circumvents it by adopting PCD as an altruistic response. Survival of the remaining population is encouraged by upregulating motility, detachment from the fragile biofilm to achieve dispersal.

Suppression of SOS repair in E. coli: possible mechanism of antimutagenicity and protective effects of common vegetables.

This study aims to understand variations in antimutagenic potential of vegetables, as observed in reduction of UV-induced mutation (Rif(S)→Rif(R)) in Escherichia coli cells. On further investigation, the juice of vegetables [eggplant (small-violet), pepper (hot Arbol), bean (French), and tomato] was found to suppress mutagenic SOS response as measured by cell filamentation, LexA degradation, and induction of defective prophage as per their antimutagenic potential. Cell filamentation which was observed in 25 and 60% of the UV- and gamma-induced cells, reduced to 2-8%, and 3-16%, respectively in the presence of the vegetable juice; moreover, LexA was also not significantly affected. Phage induction frequency reduced upto 76% compared to control UV-exposed cells. The antimutagenic effect was found to be partially dependent on recB, ruvB gene functions, and was independent of uvrA function. Phenolic compounds were found to be the major contributors to the observed antimutagenicity.

Variety-based variation in the antimutagenic potential of various vegetables and lack of its correlation with their antioxidant capacity.

As mutation causes many life-threatening diseases including cancer, a diet enriched with specific vegetables having potential to reduce mutagenesis possesses immense significance. In this study, 41 commonly used vegetables from diverse botanical taxa were evaluated and compared for their relative antimutagenic potential using standard assays [Escherichia coli RNA polymerase ß (rpoB)-based Rif(S) â†’ Rif(R) assay and Ames test] against known mutagens (UV, gamma radiation, 4-nitroquinoline-N-oxide and ethylmethanesulphonate). Significant differences in antimutagenicity were observed even among the cultivars within the same species, as well as at other phylogenetic levels such as genus or family. The effect of cooking in terms of boiling (aquathermal treatment), on the antimutagenicity of these vegetables, was also investigated. In majority of the cases, aquathermal treatment did not affect the antimutagenic potential. The antimutagenicity of these vegetables was not found to correlate well with their antioxidant properties.