DNA hypomethylation is the plausible driver of heat stress adaptation in Linum usitatissimum.

Heat stress has a significant impact on the climatic adaptation of flax, a cool-season economic crop. Genome-wide DNA methylation patterns are crucial for understanding how flax cultivars respond to heat adversities. It is worth noting that the DNA methylome in flax has yet to be investigated at the nucleotide level. Although heat stress above 40°C caused oxidative damage in flax leaves, 5-azacytidine, a hypomethylating agent, reduced this effect by 15%-24%. Differences in the expression of the LuMET1 (DNA methyltransferase) gene suggested that DNA methylation/demethylation may play a major role in the flax heat stress response. Thus, whole-genome bisulfite sequencing-derived DNA methylation profiles in flax, with or without heat stress and 5-azaC, were developed and analyzed here. In response to heat stress, a high percentage of significant differentially methylated regions (DMRs), particularly hypomethylated DMRs, were identified in the CHH nucleotide sequence context (H = A/T/C). Some of these DMRs overlapped with transposable element insertions. The majority of DMRs were discovered in intergenic regions, but several DMR loci were also found near genes relevant to heat stress response and epigenetic processes. These DMRs, in particular, are linked to CpG islands, implying a possible role in promoter methylation and gene silencing. The DMRs discovered in this study are crucial for understanding and identifying the key players in heat stress response in flax, which will help in developing climate-smart flax varieties.

Sweet Potato Peels and Cancer Prevention.

A bioassay-guided fractionation of an alcoholic extract from the peels of Ipomoea batatas Lam has been carried out. Sulforhodamine B and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were used to evaluate the anticancer and antioxidant potential, respectively, while silica gel column chromatography (CC) was used to isolate compounds that were characterized using 1D- and 2D-NMR (Nuclear Magnetic Resonance) and mass spectrometry. The alcoholic extract was fractionated into n-hexane, ethyl acetate, n-butanol, and water. The n-hexane fraction which showed the most promising anticancer activity was further fractionated via silica gel CC into IB-F002A, IB-F002B, and IB-F002C. Of these, IB-F002C was the most active with IC50 values 24.75, 47.91, 52.37, 34.17, 46.07, and 25.89 µg/ml against breast, colon-1, colon-2, ovary, lung, and head/neck cancer cell lines, respectively. The bioassay-guided isolation from IB-F002C afforded a glucocerebroside, which showed 10.51%, 12.19%, 16.14%, and 34.05% inhibition of head and neck, breast-1, colon-1, and ovarian cancer cell lines, respectively. Octadecyl coumarate, 7-hydroxycoumarin, and 6-methoxy-7-hydroxycoumarin that showed different antioxidant potentials were also identified in this study. Sweet potato peel, which is usually discarded as waste, contains constituents that can serve as dietary components to prevent the development of different types of cancer.

Untying arsenite tolerance mechanisms in contrasting maize genotypes attributed to NIPs-mediated controlled influx and root-to-shoot translocation, redox homeostasis and phytochelatin-mediated detoxification pathway.

Contamination of ground water and soil with toxic metalloids like arsenic (As) poses a serious hazard to the global agricultural food production. One of the best ways to restrict entry of As into the food chain is selection of germplasms which accrue extremely low level of As in grains. Here, we screened diverse maize genotypes under high arsenite (100 µM AsIII) stress and identified PMI-PV-9 and PMI-PV-3 as AsIII-tolerant and -sensitive maize genotype respectively. Expression of genes associated with As uptake, vacuolar sequestration, biosynthesis of phytochelatins, root-to-shoot translocation, in vivo ROS generation, fine tuning of antioxidant defense system, DNA and membrane damage, H2O2 and superoxide anion (O2•-) levels were compared among the selected genotypes. PMI-PV-9 plants performed much better than PMI-PV-3 in terms of plant growth with no visible symptom of As toxicity. Susceptibility of PMI-PV-3 to AsIII stress may be attributed to comparatively low expression of genes involved in phytochelatins (PCs) biosynthesis. Concomitant decrease in ABCC1 expression might be another key factor for futile sequestration of AsIII into root vacuoles. Moreover, up-regulation of ZmNIP3;1 might contribute in high root-to-leaf As translocation. Substantial spike in H2O2, O2•- and MDA levels indicates that PMI-PV-3 plants have experienced more oxidative stress than PMI-PV-9 plants. Appearance of prominent deep brown and dark blue spots/stripes on leaves as revealed after DAB and NBT staining respectively suggest severe oxidative burst in PMI-PV-3 plants. Marked reduction in DHAR and MDAR activity rendered PMI-PV-3 cells to recycle ascorbate pool ineffectively, which might have exacerbated their susceptibility to AsIII stress. In a nutshell, incompetent PCs mediated detoxification system and disruption of cellular redox homeostasis owing to feeble antioxidant defence system resulting oxidative burst might be the prime reasons behind reduced performance of PMI-PV-3 plants under AsIII stress.

microRNAomic profiling of maize root reveals multifaceted mechanisms to cope with Cr (VI) stress.

Chromium (Cr) contamination of soil and water poses serious threats to agricultural crop production. MicroRNAs (miRNAs) are conserved, non-coding small RNAs that play pivotal roles in plant growth, development and stress responses through fine-tuning of post-transcriptional gene expression. To better understand the molecular circuit of Cr-responsive miRNAs, two sRNA libraries were prepared from control and Cr (VI) [100 ppm] exposed maize roots. Using deep sequencing, we identified 80 known (1 up and 79 down) and 18 downregulated novel miRNAs from Cr (VI) challenged roots. Gene ontology (GO) analysis reveals that predicted target genes of Cr (VI) responsive miRNAs are potentially involved in diverse cellular and biological processes including plant growth and development (miR159c, miR164d, miR319b-3p and zma_25.145), redox homeostasis (miR528-5p, miR396a-5p and zma_9.132), heavy metal uptake and detoxification (miR159f-5p, 164e-5p, miR408a, miR444f and zma_2.127), signal transduction (miR159f, miR160a-5p, miR393a-5p, miR408-5p and zma_43.158), cell signalling (miR156j, 159c-5p, miR166c-5p and miR398b). Higher accumulation of Cr in maize roots might be due to upregulation of ABC transporter G family member 29 targeted by miR444f. Instead of isolated increase in SOD expression, significant decline in GSH:GSSH ratio and histochemical staining strongly suggest Cr (VI) stress mediated disruption of ROS scavenging machinery thus unbalancing normal cellular homeostasis. Moreover, miR159c-mediated enhanced expression of GAMYB might be a reason for impaired root growth under Cr (VI) stress. In a nutshell, the present microRNAomic study sheds light on the miRNA-target gene regulatory network involved in adaptive responses of maize seedlings to Cr (VI) stress.

The role of bacterial exopolysaccharides (EPS) in the synthesis of antimicrobial silver nanomaterials: A state-of-the-art review.

The emergence of multi-drug resistant (MDR) pathogens poses a significant global health concern due to the failure of conventional medical treatment. As a result, the development of several metallic (Ag, Au, Zn, Ti, etc.) nanoparticles, has gained prominence as an alternative to conventional antimicrobial therapies. Among these, green-synthesized silver nanoparticles (AgNPs) have gained significant attention due to their notable efficiency and broad spectrum of antimicrobial activity. Bacterial exopolysaccharides (EPS) have recently emerged as a promising biological substrate for the green synthesis of AgNPs. EPS possess polyanionic functional groups (hydroxyl, carboxylic, sulfate, and phosphate) that effectively reduce and stabilize AgNPs. EPS-mediated AgNPs exhibit a wide range of antimicrobial activity against various pathogenic microbes, including Gram-positive and Gram-negative bacteria, as well as fungi. The extraction and purification of bacterial EPS play a vital role in obtaining high-quality and -quantity EPS for industrial applications. This study focuses on the comprehensive methodology of EPS extraction and purification, encompassing screening, fermentation optimization, pretreatment, protein elimination, precipitation, and purification. The review specifically highlights the utilization of bacterial EPS-mediated AgNPs, covering EPS extraction, the synthesis mechanism of green EPS-mediated AgNPs, their characterization, and their potential applications as antimicrobial agents against pathogens. These EPS-mediated AgNPs offer numerous advantages, including biocompatibility, biodegradability, non-toxicity, and eco-friendliness, making them a promising alternative to traditional antimicrobials and opening new avenues in nanotechnology-based approaches to combat microbial infections.

Natural antifungal compounds from the peels of Ipomoea batatas Lam.

Three antifungal compounds have been isolated for the first time from the peels of Ipomoea batatas Lam. Their structures were established on the basis of 1D and 2D NMR spectra data as well as ESI-MS and IR analysis. Urs-13(18)-ene-3ß-yl acetate was found to possess a weak activity against Sporothrix schenckii and Trichophyton metagrophytes fungi with an MIC value of 50 µg/mL each. Stigmasterol and 3-friedelanol were equally active against T. metagrophytes.

Impact of nano-CuO stress on rice (Oryza sativa L.) seedlings.

Indiscriminate release of metal oxide nanoparticles (NPs) into the environment due to anthropogenic activities has become a serious threat to the ecological system including plants. The present study assesses the toxicity of nano-CuO on rice (Oryza sativa cv. Swarna) seedlings. Three different levels of stress (0.5 mM, 1.0 mM and 1.5 mM suspensions of copper II oxide, <50 nm particle size) were imposed and seedling growth performance was studied along control at 7 and 14 d of experiment. Modulation of ascorbate-glutathione cycle, membrane damage, in vivo ROS detection, foliar H2O2 and proline accumulation under nano-CuO stress were investigated in detail to get an overview of nano-stress response of rice. Seed germination percentage was significantly reduced under stress. Higher uptake of Evans blue by nano-CuO stressed roots over control indicates loss of root cells viability. Presence of dark blue and deep brown spots on leaves evident after histochemical staining with NBT and DAB respectively indicate severe oxidative burst under nano-copper stress. APX activity was found to be significantly increased in 1.0 and 1.5 mM CuO treatments. Nevertheless, elevated APX activity might be insufficient to scavenge all H2O2 produced in excess under nano-CuO stress. That may be the reason why stressed leaves accumulated significantly higher H2O2 instead of having enhanced APX activity. In addition, increased GR activity coupled with isolated increase in GSH/GSSG ratio does not seem to prevent cells from oxidative damages, as evident from higher MDA level in leaves of nano-CuO stressed seedlings over control. Enhanced proline accumulation also does not give much protection against nano-CuO stress. Decline in carotenoids level might be another determining factor of meager performance of rice seedlings in combating nano-CuO stress induced oxidative damages.