Physiologia plantarum最新文献

Seagrass meadows have been heavily affected by human activities, with Zostera marina L. (Zosteraceae) being one of the most impacted species. Seed-based methods are currently the preferred approach for their restoration, yet low germination rates and poor seedling establishment remain significant challenges. This study explored the combined effects of light spectra (white, red, and darkness), photoperiod, and gibberellic acid (GA_3-0, 50, 500, and 1000 mg L^-1) on Z. marina seed germination using a fully crossed incubation experiment. Penalised logistic regression and Cox proportional hazards analysis were chosen to account for low germination events and to analyse the temporal dynamics of germination. We found that light conditions, particularly red light and darkness, when combined with GA₃, significantly enhanced germination probability. Furthermore, mid (50 mg L^-1) and high (500 mg L^-1) GA₃ concentrations reduced time-to-germination. Morphometric analysis of the cotyledonary and leaf tissue development indicates no adverse effects of the treatments on seedling development. Our findings suggest that light and GA₃ treatments effectively improve germination success and reduce dormancy in Z. marina seeds. Seed treatments can mitigate stress- or manipulation-induced dormancy and can represent a viable strategy for on-demand germination, such as in the context of seed-based restoration efforts.

Toona sinensis, a plant species renowned for its culinary and medicinal properties, exhibits diverse colour variations that contribute to its aesthetic appeal and commercial value. Understanding the molecular mechanisms underlying colour and aroma traits in Toona sinensis is crucial for breeding programs and quality regulation in agriculture and the food industry. The present investigation included a comprehensive analysis of the transcriptomic and metabolomic profiles of Toona sinensis with different colours, including green, red, and red leaves with green stems. Metabolic analysis revealed that the flavonoid biosynthesis pathway governs the colour distinction between green and red Toona sinensis. The top 10 metabolites influenced by transcriptome include terpenoids (5), heterocyclic compounds (1), phenol (1), ketone (1), aldehyde (1), and alcohol (1). Fifteen highly expressed genes impacted by phenylpropanoid, sesquiterpenoid, and triterpenoid biosynthesis in coloured Toona sinensis. Functional annotation and pathway analysis revealed that terpene metabolites are predominantly synthesized via terpene metabolic pathway, involving eight key gene families. This study underscores the importance of multi-omics approaches in unravelling the genetic and metabolic basis of phenotypic traits in plant species aimed at improving colour, aroma, and nutritional quality in plants and derived products. HIGHLIGHTS: Flavonoid biosynthesis pathway governs the colour distinction between green and red Toona sinensis. The top 10 metabolites influenced by transcriptome include five terpenoids, one heterocyclic compound, one phenol, one ketone, one aldehyde, and one alcohol. Fifteen highly expressed genes impacted by phenylpropanoid, sesquiterpenoid, and triterpenoid biosynthesis in coloured Toona sinensis. Terpene metabolites are predominantly synthesized via the terpene metabolic pathway, involving eight key gene families. The net photosynthetic rate and intercellular CO₂ concentration are relatively high in the red Toon sinensis morph.

Zinc is an essential trace element for plant growth and development. Zinc transporters play an important role in regulating zinc homeostasis in plants. In this study, the potato cultivar 'Atlantic' was used as experimental material to analyze the expression characteristics of the StZIP2 gene in different potato tissues under zinc deficiency stress. Transgenic plants with overexpression and interference expression of the StZIP2 gene were obtained by genetic transformation and treated with zinc deficiency stress. Chlorophyll content, antioxidant enzyme activity, proline (Pro) and malonic dialdehyde (MDA) content, zinc content in aboveground parts and roots, and root indices were determined. The results showed that the expression level of the StZIP2 gene in roots, stems and leaves under zinc deficiency stress was significantly higher than that of the control, and the expression level of the StZIP2 gene in roots under zinc deficiency stress was the highest. After zinc deficiency treatment, the content of chlorophyll and Pro, the activity of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), root-to-shoot ratio, root length and root fresh weight of overexpressed plants were significantly increased, while the MDA content was significantly decreased. The ratio of zinc content between the above-ground part and the root of the overexpressed plants was significantly higher than that of the non-transgenic plants, and the transport efficiency from the root to the above-ground part was significantly increased in the overexpressed plants, whereas it was just the opposite in the interference expressing plants. The result provides basic data to further elucidate the StZIP2 gene function.

The increasing impacts of climate change and intensified human activities exacerbate soil salinization, posing significant challenges to agricultural productivity. Therefore, addressing salt stress in crops is a critical area of research. In this study, strawberry seedlings (Fragaria×ananassa Duch. 'Benihoppe') were used to investigate the alleviating effects of hydrogen-rich water (HRW) on salt stress through integrated transcriptomic and metabolomic analyses. HRW treatment was found to significantly enhance plant growth, notably increasing root biomass by 49.50%. Additionally, HRW modulated key parameters, including the levels of soluble sugars, malondialdehyde (MDA), and antioxidant enzyme activities, while promoting K⁺ uptake and Na⁺ exclusion. Transcriptomic analysis revealed that HRW induced the expression of genes associated with ion transport, antioxidant defence, and cell wall biosynthesis in roots. Metabolomic profiling identified phenolic acids, flavonoids, and amino acids as critical metabolites in HRW-mediated salt stress mitigation. Integrated multi-omics analysis highlighted two key metabolic pathways, phenylpropanoid biosynthesis and amino and nucleoside sugar metabolism, pivotal to the observed protective effects. This study provides molecular insights into the mechanisms by which HRW alleviates salt stress in strawberry seedlings, underscoring the potential of hydrogen gas applications in sustainable agriculture.

Reduced height (Rht) genes have revolutionised wheat cultivation, but they can compromise freezing tolerance, and only a few alleles are in use. Thus, evaluating the role of other Rht alleles in stress responses is crucial. Far-red supplementation of white light (W+FR) can induce pre-hardening in cereals at 15°C. However, the relevant effect of blue light enrichment (W+B) is poorly described. This study investigates the influence of W+FR or W+B exposure in young winter wheat leaves of a tall (wild-type, rht12) and a dwarf, gibberellin-deficient (near-isogenic line, Rht12) genotype in cv. Maris Huntsman background over 10 days at 15°C. The main objectives were to investigate the relationship between light quality, gibberellin homeostasis, and freezing tolerance. Key parameters such as frost injury, hormonal pools and the expression of relevant genes were examined. Results provided evidence about the involvement of Rht alleles in the basal freezing tolerance of wheat leaves from the side of gibberellin availability. It was revealed that W+FR and W+B treatments partially rescued the freezing-sensitive phenotype of Rht12 leaves, suggesting a potential compensatory mechanism. Analysis of gibberellic acid (GA) metabolism indicated differential responses to light treatments between the Rht12 and wild-type leaves, with implications for freezing tolerance. Moreover, alterations in hormone levels, including jasmonic acid (JA) and salicylic acid (SA), were observed, highlighting the complex interplay between light signalling and hormonal regulation in wheat. Overall, these findings suggest that manipulating light responses may offer a strategy to enhance freezing tolerance in gibberellin-deficient dwarf wheat genotypes.

Bermudagrass [Cynodon dactylon (L.) Pers.] is widely used for soil remediation, livestock forage, and as turfgrass for sports fields, parks, and gardens due to its resilience and adaptability. However, low temperatures are critical factors limiting its geographical distribution and ornamental season, even preventing its safe overwintering. PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) acts as a hub transcription factor, not only regulating various light responses but also integrating multiple external stimuli to improve plant productivity and architectural adaptation under adverse stress conditions, which makes it potential as a target gene. In this study, we cloned and characterized the CdPIF4 genes in bermudagrass. Expression analysis revealed that it is predominantly expressed in leaves and is regulated by photoperiod and cold stress. Using Agrobacterium-mediated genetic modification, we successfully generated CdPIF4a-overexpressing bermudagrass lines. Under cold stress at 4°C, these transgenic plants demonstrated enhanced cold tolerance, as indicated by higher relative water content, reduced membrane damage, and lower levels of lipid peroxidation levels. Photosynthetic analysis revealed that CdPIF4a-overexpressing plants exhibited higher light energy capture and transfer efficiency at this low temperature, with less energy loss. Additionally, they showed higher antioxidant enzyme activity and lower levels of reactive oxygen species levels. The responsive regulation of cold stress-related genes further validated the role of the CdPIF4a gene in enhancing cold tolerance. This study elucidates that CdPIF4 enhances cold tolerance in bermudagrass through physiological and molecular mechanisms, offering new insights and valuable genetic resources for advancing cold resistance research in bermudagrass and other grass species.

It is known that red light irradiation enhances the biosynthesis of (E)-β-caryophyllene in plants. However, the underlying mechanism connecting red light to (E)-β-caryophyllene biosynthesis remains elusive. This study reveals a molecular cascade involving the phyB-PIF4-MYC2 module, which regulates (E)-β-caryophyllene biosynthesis in response to the red light signal in Arabidopsis thaliana. In this module, phyB positively regulates (E)-β-caryophyllene biosynthesis under red light, whereas PIF4 negatively regulates it; both regulations require the involvement of MYC2, a transcription factor that can bind directly to the promoter of the TPS21 gene which encodes (E)-β-caryophyllene synthase. Importantly, protein-protein and protein-DNA interaction assays show that PIF4 reduces the binding affinity of MYC2 to the TPS21 promoter through direct interaction with MYC2. We propose that the phyB-PIF4-MYC2 module represents a universal mechanism linking red light to sesquiterpene biosynthesis in plants.

A lack of iron (Fe) inhibits the growth and development of plants, leading to reduced agricultural yields and quality. In the last ten years, numerous studies have focused on the induction of Fe uptake and translocation under Fe deficiency, but the regulatory mechanisms governing Fe reutilization within plants are still not well understood. Here, we demonstrated the involvement of the NAM/ATAF1/2/CUC2 (NAC) transcription factor NAC50 in response to Fe shortage. The content of soluble Fe was greatly reduced in nac50 mutants, leading to increased chlorosis in the newly emerging leaves under the Fe-deficient condition. Subsequent investigation revealed that the cell wall of the nac50 mutants' roots accumulated more Fe, along with an increment in hemicellulose content, indicating that a cell wall-associated Fe reutilization pathway was involved in the NAC50-regulated Fe insufficiency response. Interestingly, the expression of NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3 (NCED3), a key enzyme in the abscisic acid (ABA) biosynthetic pathway, was down-regulated in the Fe-deficient nac50 mutants, resulting in decreased endogenous ABA level and Fe-deficient sensitive phenotype. Since no direct relationship was observed between NAC50 and NCED3, this suggests a potential role of NAC50 in mediating the ABA accumulation. Moreover, exogenous ABA application in the nac50 mutant restored Fe deficiency resistance to the level observed in wild-type plants (WT), indicating that NAC50 induced the cell wall Fe reutilization potentially through the regulation of ABA accumulation.

Aphids cause massive agricultural losses through direct damage or as pathogen vectors. Control often relies on insecticides, which are expensive and not selective. An interesting alternative is to use aphid sex pheromones nepetalactone (NON) and nepetalactol (NOL) to interfere with aphid mating or attract aphid predators. Here, we explore production of these compounds in plants, as their precursors can be derived from mevalonate (MVA) and methylerythritol phosphate (MEP) pathways. By introducing six genes, including a major latex protein-like (MLPL) enzyme, we engineered a functional nepetalactol biosynthetic pathway into plants. Transient expression of these enzymes in N. benthamiana caused production of nepetalactone, without the need for external supplementation with substrates. Targeting all six enzymes into the chloroplast appeared to result in higher NON yields than just chloroplast-targeting the first two enzymes. We could not detect NOL, suggesting it is rapidly oxidised to NON. In addition, we produced NON in stably transformed Camelina sativa (Camelina) lines. Interestingly, the specific NON enantiomer was different in N. benthamiana compared to in Camelina, indicating the value of different platforms for producing specific isoforms. This opens possibilities for using plants as green factories of pheromones for baits or as pheromone dispensers that interfere with insect behaviour.