Plant Physiology and Biochemistry最新文献

Nepenthes are carnivorous plants with photoactive leaves converted into jug-shaped containers filled with the digestive fluid. The digestion requires various enzymes and reactive oxygen species (ROS) that facilitate proteolysis. Reactive nitrogen species are present in the digestive fluid of Nepenthes × ventrata, and the increased nitric oxide (NO) formation is associated with protein degradation. The aim of the work was to verify the beneficial effect of NO application into the trap on the dynamics of protein digestion and ROS homeostasis. Measurements were done using the digestive fluid or the tissue collected from the mature pitcher plants (fed) grown in a greenhouse. Two independent methods confirmed NO formation in the digestive fluid of fed and non-fed traps. NO supplementation with food into the trap accelerated protein degradation in the digestive fluid by increasing the proteolytic activity. NO modulated free radical formation (as the result of direct impact on NADPH oxidase), stimulated ROS scavenging capacity, increased -SH groups and flavonoids content, particularly at the beginning of the digestion. In non-fed traps, the relatively high level of protein nitration in the digestive fluid may prevent self-protein proteolysis. Whereas, after initiation of the digestion decreasing level of nitrated proteins in the fluid may indicate their accelerated degradation.

Therefore, it can be assumed that NO exhibits a protective effect on the fluid and the trap tissue before digestion, while during digestion, NO is an accelerator of protein decomposition and the ROS balance keeper.

Drought stress strongly restricts the growth, development, and yield of wheat worldwide. Among the various transcription factors (TFs) involved in the wheat drought response, the specific functions of many basic leucine zipper (bZIP) TFs related to drought tolerance are still not well understood. In this study, we focused on the bZIP TF TabZIP156 in wheat. Our analysis showed that TabZIP156 was highly expressed in both roots and leaves, and it responded to drought and abscisic acid (ABA) stress. Through subcellular localization and transactivation assays, we confirmed that TabZIP156 was located to the nucleus and functioned as a transcriptional activator. Overexpression of TabZIP156 in Arabidopsis enhanced drought tolerance, as evidenced by higher germination rate, longer root length, lower water loss rate, reduced ion leakage, increased proline accumulation, decreased levels of H₂O₂, O²⁻ and MDA, and improved activities of POD, SOD, and CAT enzymes. Additionally, the expression of drought- and antioxidant-related genes were significantly upregulated in TabZIP156 transgenic Arabidopsis under drought stress. However, silencing TabZIP156 in wheat led to decreased proline content, increased accumulation of H₂O₂, O²⁻ and MDA, reduced activities of antioxidant enzymes, and downregulation of many drought- and antioxidant-related genes under drought stress. Furthermore, the dual-luciferase assay demonstrated that TabZIP156 could activate the expression of TaP5CS, TaDREB1A, and TaPOD by binding to their promoters. Taken together, this study highlights the significant role of TabZIP156 in drought stress and provides valuable insights for its potential application in breeding drought-resistant wheat.

The leaf apoplast contains several compounds that play important roles in the regulation of different physiological processes in plants. However, this compartment has been neglected in several experimental and modelling studies, which is mostly associated to the difficulty to collect apoplast washing fluid (AWF) in sufficient amount for metabolomics analysis and as free as possible from symplastic contamination. Here, we established an approach based in an infiltration-centrifugation technique that use little leaf material but allows sufficient AWF collection for gas chromatography mass spectrometry (GC-MS)-based metabolomics analysis in both tobacco and Arabidopsis. Up to 54 metabolites were annotated in leaf and apoplast samples from both species using either 20% (v/v) methanol (20% MeOH) or distilled deionized water (ddH₂O) as infiltration fluids. The use of 20% MeOH increased the yield of the AWF collected but also the level of symplastic contamination, especially in Arabidopsis. We propose a correction factor and recommend the use of multiple markers such as MDH activity, protein content and conductivity measurements to verify the level of symplastic contamination in MeOH-based protocols. Neither the concentration of sugars nor the level of primary metabolites differed between apoplast samples extracted with ddH₂O or 20% MeOH. This indicates that ddH₂O can be preferentially used, given that it is a non-toxic and highly accessible infiltration fluid. The infiltration-centrifugation-based approach established here uses little leaf material and ddH₂O as infiltration fluid, being suitable for GC-MS-based metabolomics analysis in tobacco and Arabidopsis, with great possibility to be extended for other plant species and tissues.

The garden strawberry (Fragaria x ananassa Duch.) is cultivated and consumed worldwide because of the pleasant flavor and health-promoting phytochemicals of its false fruits. Monocrop cultivars produce fully ripe strawberries in about one month post-anthesis throughout the spring, while everbearing cultivars undergo additional strawberry production in autumn. In this work, we evaluated the impact of different season-dependent environmental conditions on the ripening program of an everbearing field-gown strawberry variety from autumn 2015 to spring 2016. We combined ad hoc sampling and environmental data collection with LC-MS-based untargeted metabolomics to dissect the effects of cumulative temperature and solar irradiation on fruit quality parameters and secondary metabolism during ripening. Different dynamics in specific sub-groups of metabolites were observed in strawberries experiencing distinct amounts of cumulative temperature and solar irradiation during spring and autumn. The integration of statistical analyses on collected data revealed that solar irradiation mainly affected fruit fresh weight and organic acid levels, whereas temperature had a more selective effect on the accumulation of specific flavonols, anthocyanins, and soluble sugar. These findings are of suitable interest to design further approaches for the study of the complex interactions among environmental conditions and ripening in strawberries grown in a real-world scenario.

Salt stress affects the growth of rice, which reduces grain yield. However, the mechanism of the rice response to salt stress is not fully understood. The rice salt tolerance 31 (rst31) mutant exhibits longer shoots and greater dry weight than wild type (WT) plants under salt stress conditions. Through map-based cloning and genetic complementation methods, we determined that RST31 encodes a half-size ABCG transporter protein, ABCG18. We showed that mutation of RST31 reduces DNA damage under salt stress, with less accumulation of reactive oxygen species (ROS). The deficiency of RST31 suppressed the root-to-shoot transport of cytokinin, which resulted in a decrease in cytokinin content in the shoot and an increase in cytokinin content in the root. ROS accumulated abundantly in WT and rst31 mutant plants after exogenous treatment with trans-zeatin, reducing rst31 tolerance of salt stress. Collectively, our results suggest that high cytokinin level in shoots leads to an increase in ROS content and severe DNA damage under salt stress, which lead to sensitivity to salt stress. These findings enhance our understanding of plant responses to salt stress through cytokinin pathways.

Amino acids serve as the primary means of transport and organic nitrogen carrier in plants, playing an essential role in plant growth and development. Amino acid transporters (AATs) facilitate the movement of amino acids within plants and have been identified and characterised in a number of species. It has been demonstrated that these amino acid transporters exert an influence on the quality attributes of plants, in addition to their primary function of transporting amino acid transport. This paper presents a summary of the role of AATs in plant quality improvement. This encompasses the enhancement of nitrogen utilization efficiency, root development, tiller number and fruit yield. Concurrently, AATs can bolster the resilience of plants to pests, diseases and abiotic stresses, thereby further enhancing the yield and quality of fruit. AATs exhibit a wide range of substrate specificity, which greatly optimizes the use of pesticides and significantly reduces pesticide residues, and reduces the risk of environmental pollution while increasing the safety of fruit. The discovery of AATs function provides new ideas and ways to cultivate high-quality crop and promote changes in agricultural development, and has great potential in the application of plant quality improvement.

Zinc (Zn) plays a crucial role in metabolism in both plant and animal life. Zn deficiency is a worldwide problem that has recently gotten worse. This micronutrient shortage can be largely attributed to eating foods that are poor in zinc. If biofortification methods were widely used, Zn enrichment of the organ or tissue of interest would increase dramatically. However, Zn absorption mechanisms in rice plants must be understood on a fundamental level before these methods can be used effectively. Plant systems' Zn transporters and metal chelators play a major role in regulating this intricate physiological characteristic. The Zn efficiency of specific species is affected by a variety of factors, including the plant's growth stage, edaphic conditions, the time of year, and more. Both old and new ways of breeding plants can be used for biofortification. We have highlighted the significance of recombinant and genetic approaches to biofortifying in rice. In this review, we have the metabolic role of zinc in rice, and the different transporter families involved in the transportation of zinc in rice. We have also discussed the combined approaches of agronomic and genetic in zinc biofortification in rice and potential outcomes and future predictions.

Understanding the mechanisms by which weeds develop herbicide resistance is crucial for managing resistance effectively and optimizing herbicide use. Beckmannia syzigachne, a harmful grass weed prevalent in wheat and rice-wheat rotation areas, poses a significant threat to crop productivity. A field herbicide resistance survey identified a resistant population with a new ALS mutation (Asp-376-Glu). The Glu-376-Asp population displayed varying resistance levels to seven ALS herbicides, verified using the dCAPS method. qRT-PCR analysis showed that no significant difference existed in the ALS gene expression between the Asp-376-Glu and S populations. P450 and GST inhibitors failed to reverse resistance to mesosulfuron-methyl, suggesting no involvement of P450- and GST-based metabolic resistance. Molecular docking indicated that the Asp-376-Glu mutation reduces the binding affinity between ALS-inhibitors and BsALS. The findings provide valuable insights into herbicide resistance mechanisms for weed resistance control.

—Action potential (AP) of excitable plant cells is an important signaling event that can differentially alter physicochemical and physiological processes in various parts of the same cell. In giant cells of characean algae, the AP propagation has minor effect on photosynthetic electron transport in areas with high activity of plasmalemmal H⁺-pump but inhibits linear electron flow in regions featuring high passive H⁺/OH⁻ conductance of the plasma membrane (PM). Uneven spatial distributions of local periplasmic and cytoplasmic pH facilitate the operation of distinct (CO₂-dependent and O₂-mediated) pathways of photoinduced electron flow, which presumably accounts for differential influence of AP on photosynthesis. The excitation of Chara australis cell in the presence of methyl viologen (MV), a redox mediator with the prooxidant action, provides a convenient model system to clarify the influence of voltage-dependent ion fluxes across PM on photosynthetic activity of chloroplasts. This study shows that permeation of MV to their target sites in chloroplasts is restricted by PM in resting cells, but MV easily passes through ionic channels opened during the PM depolarization. This gated permeation of MV gives rise to strong non-photochemical quenching, decrease in the effective quantum yield of linear electron flow, apparent O₂ uptake, and, finally, the enhanced ROS production, as detected by the fluorescent probe dichlorofluorescein. Taken together, the results indicate that the AP generation in the presence of MV acts as trigger for instant redirection of photosynthetic linear electron flow from CO₂-dependent route to the path of O₂ reduction with the eventual formation of H₂O₂ as a dominant and most stable ROS form.

Drought is a major challenge for the cultivation of durum wheat, a crucial crop for global food security. Plants respond to drought by adjusting their mineral nutrient profiles to cope with water scarcity, showing the importance of nutrient plasticity for plant acclimation and adaptation to diverse environments. Therefore, it is essential to understand the genetic basis of mineral nutrient profile plasticity in durum wheat under drought stress to select drought-tolerant varieties. The research study investigated the responses of different durum wheat genotypes to severe drought stress at the seedling stage. The study employed an ionomic, molecular, biochemical and physiological approach to shed light on distinct behaviors among different genotypes. The drought tolerance of SVEMS16, SVEVO, and BULEL was related to their capacity of maintaining or increasing nutrient's accumulation, while the limited nutrient acquisition capability of CRESO and S.CAP likely resulted in their susceptibility to drought. The study highlighted the importance of macronutrients such as SO₄²⁻, NO₃⁻, PO₄³⁻, and K⁺ in stress resilience and identified variant-containing genes potentially influencing nutritional variations under drought. These findings provide valuable insights for further field studies to assess the drought tolerance of durum wheat genotypes across various growth stages, ultimately ensuring food security and sustainable production in the face of changing environmental conditions.