Engineered nanomaterials have increased for their positive impact in improving many sectors of economy including agriculture. Silver nanoparticles (AgNPs) have been implicated nowadays to enhance seed germination, plant growth, improvement of photosynthetic quantum efficiency and as antimicrobial agents to manage plant diseases. In this study, we examined effect of AgNPs dosage on seed germination of three plant species; corn (Zea mays L.), watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) and zucchini (Cucurbita pepo L.). Therefore, this experiment designed to study the effect of AgNPs on germination percentage, germination rate, mean germination time, root length, fresh and dry weight of seedling for the three spices. Seven concentrations (0.05, 0.1, 0.5, 1, 1.5, 2 and 2.5 mg/L) of AgNPs were examined at seed germination stage. The results showed that the three spices revealed different dosage response to AgNPs on germination percentage and the measured growth characters. Germination rate values were enhanced for the three plants in response to AgNPs. Significant enhancement in germination percentage values for watermelon and zucchini plants were observed by treatment with AgNPs in comparison with nontreated seeds. AgNPs showed toxic effect on corn roots elongation whereas watermelon and zucchini seedling growth were positively affected by certain concentration of AgNPs. This study showed that exposure to AgNPs caused both positive and negative effects on plant growth and germination.

Lead pollution of the environment poses a major global threat to the ecosystem. Bacterial bioremediation offers a promising alternative to traditional methods for removing these pollutants, that are often hindered by various limitations. Our research focused on isolating lead-resistant bacteria from industrial wastewater generated by heavily lead-containing industries. Eight lead-resistant strains were successfully isolated, and subsequently identified through molecular analysis. Among these, Enterobacter kobei FACU6 emerged as a particularly promising candidate, demonstrating an efficient lead removal rate of 83.4% and a remarkable lead absorption capacity of 571.9 mg/g dry weight. Furthermore, E. kobei FACU6 displayed a remarkable a maximum tolerance concentration (MTC) for lead reaching 3,000 mg/L. To further investigate the morphological changes in E. kobei FACU6 in response to lead exposure, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed. These analyses revealed significant lead adsorption and intracellular accumulation in treated bacteria in contrast to the control bacterium. Whole-genome sequencing was performed to gain deeper insights into E. kobei’s lead resistance mechanisms. Structural annotation revealed a genome size of 4,856,454 bp, with a G + C content of 55.06%. The genome encodes 4,655 coding sequences (CDS), 75 tRNA genes, and 4 rRNA genes. Notably, genes associated with heavy metal resistance and their corresponding regulatory elements were identified within the genome. Furthermore, the expression levels of four specific heavy metal resistance genes were evaluated. Our findings revealed a statistically significant upregulation in gene expression under specific environmental conditions, including pH 7, temperature of 30°C, and high concentrations of heavy metals. The outstanding potential of E. kobei FACU6 as a source of diverse genes related to heavy metal resistance and plant growth promotion makes it a valuable candidate for developing safe and effective strategies for heavy metal disposal.

VERNALIZATION INSENSITIVE 3 (VIN3) is a chromatin remodelling protein that is induced by low temperatures and is required for the vernalization response in Arabidopsis thaliana. VIN3 is one of the polycomb group (PcG) proteins, which mediates epigenetic repression of FLOWERING LOCUS C (FLC) in A. thaliana. Here, we present cloning, characterization, and expression of a putative SlVIN3 gene in tomato (Solanum lycopersicum L.) by isolating cDNA clones corresponding to SlVIN3 gene using primers designed based on conserved sequences between PcG genes in A. thaliana and tomato. The SlVIN3 cDNAs were cloned into a pBS plasmid and sequenced. Both 5′ and 3′ RACE were generated and sequenced. The flcDNA of 2 823 bp length for the SlVIN3 gene was composed of 5’UTR (336 bp), ORF (2 217 bp), and 3’UTR (270 bp). The translated ORF encoded a polypeptide of 739 amino acids. Alignment of deduced amino acids indicates that there are highly conserved regions between tomato SlVIN3 predicted protein and plant VIN3 gene family members. Both unrooted phylogenetic trees constructed using the maximum parsimony and maximum likelihood methods indicate that there is a close relationship between SlVIN3 predicted protein and VIN3 protein of Vitis vinifera. The expression of SlVIN3 gene remained high during floral organ differentiation and growth and decreased when the fruit started to develop.