Physiology and Molecular Biology of Plants最新文献

Cadmium (Cd) severely inhibits plant growth. While our previous physiological study established that the protein kinase gene NtGCN2 enhances Cd tolerance in tobacco, the underlying molecular mechanisms remained unknown. Here, we conducted comparative transcriptomic profiling of NtGCN2-overexpressing, NtGCN2-silenced, and K326 under Cd stress to bridge this molecular gap. Critically, our analysis moves beyond confirming known physiological phenotypes (e.g., enhanced antioxidant activity) to reveal the unexpected and multi-layered transcriptional logic orchestrated by NtGCN2. We discovered that NtGCN2 expression correlates with a coordinated transcriptional program that simultaneously (1) preserves glutathione pools by downregulating the glutathione-degrading enzyme Chac2-a previously unrecognized mechanism supporting both ROS scavenging and phytochelatin synthesis; (2) restructures cell wall architecture via coordinated upregulation of cellulose (CSLG2) and pectin-modifying (PME45) genes alongside suppression of a lignin inhibitor (SCL14); (3) sustains nitrogen assimilation by upregulating nitrate transporters (NPF8.1, NRT2.5) and reductase (NIA); and (4) orchestrates multilayered Cd detoxification including uptake suppression (bHLH37↓), chelation (PCS1↑), and vacuolar sequestration (HIPPs, CAX6↑). WGCNA further identified co‑expression modules correlated with Cd tolerance traits, and hub genes independently supported the DEG‑based findings. These findings suggest that NtGCN2 is associated with a putative transcriptional hub that may integrate growth, metabolism, and detoxification pathways, providing candidate genes and a testable framework for future functional validation. We provide a mechanistic model and a rich set of candidate genes for engineering heavy metal tolerance in crops.

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Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01776-6.

Stevia rebaudiana Bertoni is a globally recognized natural sweetener owing to its zero-calorie steviol glycosides (SGs). However, drought stress, one of the leading abiotic constraints to crop productivity, adversely affects stevia growth and development, while simultaneously altering its biochemical composition. This review highlights the impact of polyethylene glycol (PEG)-induced drought stress on stevia, with particular emphasis on agronomic traits, metabolites, antioxidant activities, and SGs biosynthesis. PEG-mediated stress reduces key growth parameters, such as plant height, biomass, and leaf area, but in some cases, it promotes root elongation as an adaptive strategy to optimize water uptake. Such alterations are accompanied by biochemical adjustments, notably the up-regulation of antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), which neutralize reactive oxygen species (ROS)-induced oxidative stress. Moreover, PEG stress enhances the accumulation of secondary metabolites, such as phenolic, flavonoids and terpenoids, thereby improving antioxidant potential and stress tolerance. Notably, PEG-induced drought stress shapes SG biosynthesis through the up-regulation of the methylerythritol phosphate (MEP) pathway and the differential expression of key SG-related genes. Such modulation frequently increases SG accumulation, thereby strengthening their medicinal and economic value. Overall, this review covers the dual nature of PEG-induced drought stress: while limiting agronomic performance, enhances SGs biosynthesis and antioxidant capacity. Gaining insights into these mechanisms will facilitate the development of optimized cultivation strategies under water deficit conditions. Future research should prioritize molecular breeding and advanced biotechnological approaches to enhance drought tolerance and maximize the production of bioactive metabolites in stevia.

N-acetyl-L-thiazolidine-4-carboxylic acid (NATCA) is an organic amino acid derivative that functions as a plant growth regulator, enhancing growth and nutrient utilization in fruit trees and various crops. However, the molecular responses underlying its growth-promoting effects remain poorly understood. Here, we demonstrate that NATCA significantly promotes the growth and development of wheat (Triticum aestivum), with application at different concentrations enhancing physiological performance in stems, leaves, and roots. Treatment with 0.7 mg/L NATCA yielded the most pronounced positive effects. Under this treatment, chlorophyll content, free amino acids (FAA), soluble protein (SP), fresh weight, and dry weight all significantly increased compared to the control. Furthermore, NATCA elevated the activities of antioxidant enzymes including peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD). Transcriptome analysis identified 743 differentially expressed genes (DEGs, 505 up-regulated and 238 down-regulated) in response to NATCA. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment in phenylpropanoid biosynthesis (taes00940), starch and sucrose metabolism (taes00500), plant hormone signal transduction (taes04075), and biosynthesis of secondary metabolites. Notably, 49 DEGs (47 up, 2 down) were associated with phenylpropanoid biosynthesis, suggesting its potential involvement in NATCA-induced growth responses. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) validated the expression patterns of seven selected DEGs. Collectively, these findings indicate that NATCA treatment associates with extensive transcriptional reprogramming and enhanced physiological performance in wheat seedlings. The observed enrichment of phenylpropanoid-related genes may contribute to growth promotion and biomass accumulation, although further biochemical and functional studies are required to establish causal relationships.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01799-z.

[This corrects the article DOI: 10.1007/s12298-025-01650-x.].

G-quadruplexes are non-canonical DNA structures formed by guanine-rich sequences that regulate gene expression and genome stability. Despite AT-rich phytoplasma genomes, their G-quadruplex potential remains unexplored. We performed genome-wide mapping, comparative analyses and biophysical validation of putative G-quadruplex forming sequences (PGQSs) in four phytoplasma strains: Onion yellows phytoplasma, Aster yellows witches'-broom phytoplasma, 'Candidatus Phytoplasma australiense' and 'Candidatus Phytoplasma mali'. We identified 376 (OY-M, previously reported by Singh and Lakhanpaul 2019), 286, 340 and 129 PGQSs in OY-M, AY-WB, AUSGY and AT, respectively, with densities of 0.2143-0.4407 PGQSs/Kbp. Strong positive correlations between GC content and PGQS density occurred in whole genomes and genic regions, while regulatory and repeat-rich regions showed weak correlations, suggesting functional enrichment beyond GC bias. PGQSs were enriched in putative regulatory regions and essential Sec translocation pathway genes (secA and secY). Circular dichroism spectroscopy and native PAGE confirmed parallel and mixed G4 topologies in vitro, while mutated controls failed to form stable structures. These findings highlight non-random distribution and potential regulatory significance of G-quadruplexes in phytoplasma genomes, providing insights into molecular mechanisms underlying phytoplasma pathogenicity.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01801-8.

Pre-sowing halopriming with sodium chloride (NaCl) was evaluated as a strategy to improve germination, growth, physiological performance, and rhizome yield in turmeric (Curcuma longa L. cv. IISR Pragati) through a multi-year assessment. A preliminary optimization experiment evaluating NaCl concentrations from 0 to 500 mM in a randomized design with three replicates identified 250 mM as the optimal priming concentration, resulting in the highest germination (92.66%) and improved physiological and biochemical responses, whereas higher concentrations were inhibitory. The optimized treatment was subsequently evaluated over three consecutive years (2022-2025) under open growbag conditions. NaCl priming exerted significant treatment effects (P < 0.05) across all parameters, enhancing germination (92.77-94.44%) and vegetative growth, while year and interaction effects were largely non-significant for most traits, indicating consistent performance. Primed plants exhibited higher relative water content (92.58%) and increased chlorophyll and carotenoid contents, indicating improved physiological status. Biochemical analysis showed increased carbohydrate and protein accumulation, elevated proline levels, and reduced malondialdehyde (MDA), reflecting improved osmotic adjustment and membrane stability. SDS-PAGE analysis revealed changes in protein banding patterns and band intensity, suggesting modulation of the overall leaf protein profile following NaCl priming. These physiological and biochemical responses were accompanied by enhanced rhizome development, with fresh rhizome yield increasing from 95.0 to 147.83 g plant^- 1 in the control to 287.45-339.56 g plant^- 1 in primed plants across years. Curcumin and essential oil contents were also improved. Overall, NaCl halopriming at 250 mM provides a practical pre-planting treatment for enhancing turmeric growth, yield, and quality under the tested conditions. Further field validation across diverse agro-climatic regions is required to confirm its broader applicability.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01810-7.

The cytoplasmic-genic male sterility (CGMS) system enhances the economic efficiency of F₁ hybrid seed production by exploiting the interaction between sterile cytoplasm and nuclear restorer-of-fertility (Rf) genes. Molecular markers linked to the Rf gene facilitate the development of stable CMS lines by enabling fixation of the recessive rf allele in male-sterile (A) and maintainer (B) lines, identification of restorer lines, and assessment of genetic purity. In the present study, phenotyping of an F₂ population derived from IIHR4392A (rfrf) × IIHR4597R (RfRf) showed a 3:1 segregation ratio, confirming monogenic dominant inheritance of fertility restoration. Genotyping-by-sequencing (GBS) of this segregating F₂ population yielded 10,443 single-nucleotide polymorphisms (SNPs) with 481 to 1,074 SNPs per chromosome. Bulk segregant analysis identified three SNPs co-segregating with the Rf gene on chromosome 6. One candidate SNP, mapped at 2,343,509 bp on chromosome 6, was converted into a derived cleaved amplified polymorphic sequence (dCAPS) marker and validated in the F₂ population. Three putative candidate genes, i.e., two fertility restorer-like proteins (CA06g01070, CA06g01090) and a pentatricopeptide repeat protein (CA06g01100), were predicted as potential Rf candidates. The developed dCAPS marker associated with the Rf gene for fertility restoration provides a valuable tool for marker-assisted breeding in chilli.

Metal(loid) contamination is a significant threat to environmental health and agricultural productivity, as it can cause toxic elements such as lead, arsenic, or cadmium to accumulate in plants and enter the food chain. In recent years, the use of nanoparticles (NPs) and other approaches in nanotechnology has become a viable solution to this problem. Several mechanisms can be utilized by nanoscale materials to control plant metal (loid) accumulation, such as complexation of metal ions, transformation of toxic metals into more manageable forms, immobilization of harmful contaminants in the soil for preventative use, and modification of physiological pathways for improving plant tolerance. In this review, a comprehensive analysis of engineered nanoparticles, including metal-based NPs (e.g. iron oxide, zinc oxide), carbon-derived nanomaterials like graphene oxide and carbon nanotubes, and hybrid nanocomposites, is presented to illustrate their roles in controlling the uptake/translocation and detoxification of metal(loid)s in plants. The paper underscores the environmental consequences of nanoparticle usage, such as possible toxicity and ecological survival, while also highlighting important knowledge shortcomings, including the necessity for extended research or fieldwork. Additionally, the article culminates with a list of suggested research paths for enhancing the safe and effective application of nanotechnologies in sustainable agriculture and environmental remediation. Consistent with the scope of the available mechanistic evidence, the review focuses specifically on the two most widely cultivated staple cereals, rice (Oryza sativa L.) and wheat (Triticum aestivum L.), which together account for the majority of dietary metal(loid) exposure through cereal grain worldwide, and draws on Arabidopsis thaliana only as a model system for resolving the underlying molecular mechanisms.

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Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01803-6.

Herbivory represents an important ecological pressure influencing plant structure and function, yet the integration of morphological and physiological responses under natural browsing remains insufficiently understood. In Olea europaea L. subsp. cuspidata, a widely distributed wild olive species in Punjab, Pakistan, we compared morpho-anatomical, biochemical, and physiological traits between browsed and non-browsed populations across ecologically distinct regions. Browsed populations exhibited pronounced phenotypic variation, characterized by a shift toward a compact, shrubby architecture with reduced leaf size, increased branching, and higher squama density. Concurrent changes included reduced stomatal size and density, thinner cortical and vascular tissues, and lower photosynthetic pigment and ionic contents. In contrast, levels of phenolics, antioxidant enzymes, and osmoprotectants were generally elevated in browsed plants, suggesting a potential trade-off between growth-related traits and stress-associated responses. The combination of structural and biochemical traits observed in browsed individuals is consistent with plant responses commonly associated with herbivory and environmental stress. However, as herbivore pressure, feeding rates, and preference were not directly quantified, these trait shifts should be interpreted as correlates of browsing exposure rather than definitive evidence of herbivore deterrence or resistance mechanisms. Overall, this study provides an integrated assessment of trait variation associated with browsing in O. europaea subsp. cuspidata, while highlighting the need for direct herbivore interaction studies to clarify functional defense roles.