UDP-glycosyltransferases (UGT) family enzymes are core genes for glycosylation of ginseng active ingredients (including polysaccharides and ginsenosides), transferring activated sugar moieties from nucleotide sugar donors to acceptors of secondary metabolites and polysaccharide intermediates. These active ingredients are widely used for replenishing vital energy and treating tumors but rely on traditional cultivation and extraction, limited by narrow suitable planting areas, long growth cycles, and low resource utilization. Based on the Panax ginseng telomere-to-telomere (T2T) genome, this study identified 167 UGT members via bioinformatics. Most localize to the cell membrane and chloroplasts, with only 4 containing a transmembrane domain. Phylogenetic analysis first revealed the ginseng-specific P-W subgroup; all members harbor 5 conserved motifs and the GT1_Gtf-like conserved domain, distributing unevenly across 24 chromosomes. Thirty-four types of promoter cis-acting elements were predicted, with light-responsive elements being the most abundant. Candidate genes related to polysaccharide synthesis showed regulated expression under salt, low-temperature, heavy metal, and PEG-induced osmotic stress. This study provides key genetic resources for elucidating ginseng polysaccharide biosynthesis, facilitating sustainable resource utilization and modernization of traditional Chinese medicine.
Plant growth-promoting microorganisms (PGPR) inoculated with seeds represent an innovative method in sustainable agriculture, and for improving crop performance in various environmental conditions. Microbial seed treatment promotes better germination, improve nutrient availability, stronger seedlings, water-use efficiency, stimulate root growth architecture and enhanced plant health, thus decreasing dependence on traditional chemical inputs. It modulates phytohormones including auxin, cytokinins, and abscisic acid, which support better plant development under stress. Environmental conditions including salinity, water deficit, metal toxicity stress, and other abiotic stresses, along with desiccation and temperature variations, pose considerable challenges, as they can greatly undermine microbial integrity and functionality. Microbial seed coating under water-deficit condition triggers stress-responsive gene expression, including dehydrins and aquaporins, which assist in maintaining cellular balance and improve stress adaptation. The intricate biochemical and physical processes, including exopolysaccharide production enhances rhizosheath stability, the activity of ACC-deaminase for regulating ethylene, and the induction of antioxidant defense systems for the detoxification of reactive oxygen species (ROS) support seedlings in overcoming challenging conditions. Beneficial microbes modulate plant signaling pathways including MAPK pathways, abscisic acid and dehydration‑response/antioxidant genes inducing systemic tolerance that integrates osmotic adjustment, hormonal tuning, and defense activation. Emerging research should focus on developing climate-resilient, multi-strain microbial seed treatments with enhanced shelf life and field performance under diverse abiotic stress conditions.
Melatonin (MT) is a critical regulator of mitochondria that affects bioenergetics, dynamics, and gene expression, and effectively protects them from oxidative stress. In this study we elucidated the role of the putative melatonin receptor CAND2/PMTR1 in mitochondrial respiration and the melatonin-mediated expression of mitochondrial genes under high light (HL) stress. Disruption of CAND2 and its associated partner GPA1 in Arabidopsis thaliana resulted in an increase in the respiration rate predominantly due to cytochrome respiration (CP), in contrast to wild type (WT) plants and 35SCAND2 overexpressing line in which an increase of alternative respiration (AP) prevails. MT treatment decreased AP activation under HL and reduced the overall leaf respiration rate, however, these effects were less pronounced in cand2 and gpa1 mutants. Increase in an AP capacity under HL stress positively correlated with an increase in transcript accumulation of the alternative oxidase (AOX) genes (AOX1a, AOX1d). At the same time, under stress conditions, the expression of the studied CP genes (cob, cox1) and the ATPase gene (atp6-1) was suppressed. MT treatment completely removed this inhibition, but only in WT and 35SCAND2 plants. Moreover, cand2 showed elevated steady state transcript levels of genes associated with mitochondrial dysfunction, suggesting an initial stress state of the mutant. The effects of exogenous melatonin on mitochondrial gene activity were mainly dependent on CAND2 receptor activity, although some genes were regulated by melatonin independently of CAND2, indicating the multiple mechanisms of melatonin perception in plants. Thus, disruption of MT signaling has a significant impact on mitochondrial respiration and mitochondrial gene expression.
This study focused on a unique cross-pollinated (self-incompatible) genotype of Indian Mustard for successful seed production and its maintenance. Protogynous (PG) line identified in Indian mustard is found to be self-incompatible (SI) which would be an alternate system to be used as female line in hybrid development. Fluorescence microscopic investigation was made to understand the interaction between developing pistil and pollen of PG-SI, PG, Non-PG and cytoplasmic male sterile (CMS) lines. Intra-specific crosses of (PG-SI) × (PG-SI) did not show single pollen germination on the stigmatic surface and, consequently, no pollen tube growth was observed up to three days after pollination. Stigma of flower in PG-SI plants treated with salts and hormone like NaCl (0.34 M), GA3 (1.45 mM) and Kinetin (2.23 mM) and their interaction showed successful selfing during maintenance of SI Plants. NaCl treatment was found to be more successful in breaking self-incompatibility in PG-SI lines. The entire process of intra-specific PG-SI × non-PG-SI and treated (PG-SI) × (PG-SI) post pollination events, starting from pollen deposition on the surface of the stigma and into the embryo sac, was rapid and completed within two days of pollination. This study establishes seed setting efficiency upon crossing similar to that found in self-compatible plants which is important for successful base line for SI based hybrid development.
Capsicum annuum is the most widely grown spice crop worldwide. However, salinity is one of the major abiotic stresses that affects crop plants. Our previous reports have identified Bacillus zhangzhouensis as effective in alleviating C. annuum salt stress. In this work, the RNA-seq analysis of plants under salt stress, grown with and without B. zhangzhouensis was used to elucidate plant salt-stress-alleviating mechanisms. Capsicum annuum plants were cultivated under the following conditions: (i) plants without salt stress, (ii) plants under salt stress, (iii) plants inoculated with B. zhangzhouensis without salt stress, and (iv) plants inoculated with B. zhangzhouensis and salt stress. Leaf tissue samples were collected at the end of the experiment. A total of 101 984 contigs were assembled, and the differentially expressed genes (DEGs) were obtained for each treatment. The results showed that salt stress led to a greater number of DEGs in C. annuum. Likewise, the presence of B. zhangzhouensis decreased the number of DEGs. Moreover, the analysis by GO and KEGG showed 6 main metabolic pathways involved in the three treatments. Finally, the results showed that the ethylene pathway was one of the main pathways involved in the response to the different treatments. In conclusion, our data provide a better understanding of the transcriptional changes in the molecular mechanism by which these bacterial inoculants ameliorate the deleterious effect of salt stress in C. annuum plants.
