Physiologia plantarum最新文献

Water deficit negatively affects crop yield and quality. Biostimulants, such as brown seaweed extracts, offer a sustainable solution to mitigate these effects. This study evaluated the impact of Laminaria digitata-aqueous extract (LE) on tomato performance and its potential to alleviate drought stress by examining morphological, physiological, and metabolic responses. Two-week-old tomato plants were foliar-sprayed with LE (0.0, 0.1, and 1.0 g L^-1) and split into well-watered (WW) and water-limited (WL) groups. WW plants received regular irrigation, while WL faced a one-week drought. Then, half of the WL plants were rewatered and allowed to recover for 24 h (REC group). In general, LE effects were influenced by irrigation conditions, mainly impacting physiological and metabolomic parameters. Under WW conditions, LE decreased chlorophyll content, improved energy conversion by regulating photosystem antenna size, enhanced photochemical efficiency (ΦPSII) and gas exchange parameters (g_s, C_i, P_N), and promoted photosynthesis through stomatal modulation and RuBisCO activity. Conversely, under WL conditions, LE (especially 0.1 g L^-1) decreased gas exchange parameters, but increased water use efficiency by inducing stomatal closure without impairing CO₂ assimilation. LE-treated plants exhibited ROS detoxification and phytohormone downregulation, which in turn negatively affected the content of certain secondary metabolites (e.g., catechin). Phytohormone modulation may result from reduced ROS levels or crosstalking with LE compounds, including mannitol, alginates, laminarans, minerals, and phlorotannins, which likely act synergistically to improve physiological regulation. Overall, LE application improved drought tolerance by enhancing photosystem regulation, phytohormone modulation, and antioxidant capacity in tomato plants, highlighting its potential use as a biostimulant for sustainable agriculture.

Camellia oleifera Abel. is an important woody oil tree species in China, and increasing the content of polyunsaturated fatty acids (PUFAs), particularly α-linolenic acid (ALA), is critical for improving the quality of its oil. Fatty acid desaturase 7 (FAD7) is a key enzyme in ALA biosynthesis in plants. However, the allelic variation, functional role, and regulatory mechanisms underlying FAD7-mediated ALA accumulation in C. oleifera remain poorly understood. In the study, we cloned three homologous CoFAD7 genes: CoFAD7-1, CoFAD7-2, and CoFAD7-3 from C. oleifera 'Huashuo'. All three genes contained eight exons and seven introns, encoding 452 amino acids. Expression analysis revealed that CoFAD7 was highly expressed during the fruit maturation stage (258-333 DAP), correlating positively with seed ALA accumulation. Haplotypes analysis and transgenic experiments identified CoFAD7-G as a superior genotype associated with higher ALA content. Biochemical assays further showed that the transcription factor CoAP2-3 binds to the CoFAD7 promoter and activates its expression. These findings suggest that CoFAD7-G is a key determinant of ALA content, providing a theoretical basis for the early identification of high-ALA C. oleifera germplasm.

Nitrogen (N) availability is a key determinant of plant growth and development. Here, we investigate how different N sources shape Arabidopsis thaliana root system architecture, metabolism and hormone dynamics. L-glutamine (L-GLN) significantly enhances root biomass compared to nitrate (KNO₃) without compromising shoot growth. This effect emerges after 2 weeks and is independent of L-GLN's role as a carbon or ammonium source or of potential L-GLN-induced pH changes due to ammonium release, indicating a specific function of L-GLN as a N source and signaling molecule. A reverse genetic screen identified AMINO ACID PERMEASE 1 (AAP1)-mediated uptake and GLUTAMINE SYNTHETASE (GS)-dependent assimilation as essential for L-GLN-induced root biomass. In contrast, the N-sensing regulators NITRATE TRANSPORTER 1.1 (NRT1.1) and AMMONIUM TRANSPORTER (AMT) family members contribute to the differential root responses between KNO₃ and L-GLN. Metabolic profiling revealed distinct amino acid signatures under these N sources, irrespective of genotype. Hormonal analyses showed that L-GLN modulates auxin homeostasis, with auxin supplementation restoring primary root growth and lateral root symmetry under L-GLN conditions. L-GLN also reconfigures cytokinin balance by elevating cZ while reducing tZ, collectively shaping root system architecture through hormone-dependent regulation. Together, these findings establish L-GLN as an integrator of N metabolism and hormone signaling in root development, highlighting its signaling capacity beyond nutrient supply and offering new perspectives for improving N use efficiency.

Understanding soil microbiota dynamics is essential for enhancing bio-sustainability in agriculture, yet the complexity of microbial communities hampers the prediction of their functional roles. Artificial intelligence (AI) and machine learning (ML) offer powerful tools to analyse high-dimensional microbiome data generated by high-throughput sequencing. Here, we apply unsupervised AI-based algorithms to uncover microbial patterns that are not immediately recognisable but are crucial for characterising the biological status of agricultural soils. Soil samples were collected from a site in Northern Italy managed under four strategies: conventional farming without organic matter (C), with organic matter (C + O), with beneficial microorganisms but without organic matter (M), and with both beneficial microorganisms and organic matter (M + O). Metagenomic amplicon sequencing of the 16S ribosomal RNA (rRNA) gene and the internal transcribed spacer (ITS) region was used to profile bacterial and fungal communities. Principal component analysis (PCA), k-means clustering, and t-distributed stochastic neighbour embedding (t-SNE) revealed coherent temporal trajectories in both datasets, with sampling time and crop presence emerging as dominant drivers of community assembly and only subtle compositional shifts attributable to treatments. Fungal communities exhibited higher plasticity and a stronger response to management than bacterial communities, which converged towards a stable oligotrophic core. Our findings highlight the complementary roles of fungal and bacterial guilds and show that unsupervised ML-based workflows provide an effective framework to disentangle temporal and treatment effects in complex microbiome datasets. This exploratory study lays the groundwork for future predictive models aimed at identifying microbial indicators of soil biological status and supporting bio-sustainable agronomic decisions.

To explore how plant growth-promoting rhizobacteria (PGPR) regulate stress-tolerant plant growth and enhance heavy metal remediation under combined cadmium (Cd) and salt stress, we conducted hydroponic experiments using Suaeda salsa inoculated with Escherichia coli-10,527. We investigated the changes in plant growth and stress tolerance, Cd translocation, cell ultrastructure, Cd subcellular distribution, and gene expression under hydroponic conditions. The results showed that inoculation improved plant biomass, stress tolerance, and Cd uptake, particularly under low Cd/salt concentrations. E. coli-10,527 colonized lateral root zones and secreted extracellular polymeric substances (EPS), which promoted flavonoid accumulation (by 12.68%-36.76%), thereby enhancing root growth and Cd accumulation. Compared with the uninoculated control, E. coli-10,527 inoculation altered the subcellular distribution of Cd in S. salsa; the proportion of Cd in the cytoplasm increased from 16.29% (29.06%) to 24.28% (45.57%) in roots (shoots). Transcriptomic analysis revealed the upregulation of genes (ZIPA, NRAMP3, and HMA4) potentially involved in enhanced Cd transport and vacuolar sequestration. Overall, inoculation with E. coli-10,527 can promote root development in S. salsa under Cd and salt stress, while facilitating simultaneous phytoremediation of Cd and salt. This study provides an effective microbial inoculation strategy for Cd remediation in saline soils affected by combined stresses.

Proteomics is defined as the identification, quantification, and characterization of the complete set of proteins expressed in a cell or tissue under specific conditions. The last two decades have witnessed rapid advancements in proteomics technologies, including the development of the Data-Independent Acquisition (DIA) mode, which has significantly improved the sensitivity, reproducibility, and depth of proteome coverage. These advancements, together with the development of cutting-edge data analysis tools, have undoubtedly facilitated the identification of stress-responsive proteins and potential biomarkers in different organisms. However, the identification of such stress-responsive proteins, particularly in plants, remains relatively challenging because of the presence of various high-abundance proteins such as RuBisCO, which hinders the identification and subsequent characterization of these stress-responsive proteins due to their low abundance. More recently, a four-dimensional (4D) proteomics approach has been introduced, which includes "ion mobility" as the fourth dimension to classical quantitative proteomics. This 4D-proteomics method utilizes trapped ion mobility spectrometry (TIMS) combined with parallel accumulation-serial fragmentation (PASEF), which significantly enhances the sensitivity and coverage of proteomics experiments, thus allowing the detection of low-abundance proteins. This review highlights the evolution of proteomic technologies, the development of the 4D proteomics workflow, and their potential application in unraveling the molecular mechanisms underlying plant responses to environmental stress conditions. In essence, this review article provides a comprehensive overview of the state-of-the-art in proteomics, emphasizing its transformative impact on plant science research and its potential to understand crop stress resilience.

The accumulation of excess manganese (Mn) is toxic to plants and limits agricultural productivity. Although selenium (Se) is known to be a beneficial element that can alleviate heavy metal stress, its role in mitigating Mn-related stress remains insufficiently explored. This research explores the effects of Se (applied as sodium selenite at 0.5 μM) on 0.5 mM Mn toxicity in Malus robusta seedlings, focusing on Mn accumulation, physiological performance, polyamine metabolism, proline biosynthesis, and the enzymatic activity and expression levels of critical genes. Exogenous Se significantly reduced Mn accumulation and alleviated Mn toxicity, as evidenced by enhanced root growth, increased photosynthetic pigments, improved fluorescence parameters (Fv/fm and ΦPSII), and maintained antioxidant balance via a reduced production of reactive oxygen species (ROS) and an activation of the antioxidant system. Moreover, total putrescine (Put) and spermine (Spm) contents declined after Se application, whereas spermidine (Spd) levels showed no noticeable change. This led to an increased (Spd + Spm)/Put ratio, highlighting the pivotal role of Put reduction in Mn stress response. A decrease in Put corresponded with significant downregulation of ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) activities and gene expressions. Furthermore, soluble conjugated and insoluble bound polyamines followed a similar trend, except for a notable increase in bound Spd. In addition, Se treatment decreased proline (Pro) content mainly through the suppression of ornithine aminotransferase (OAT; EC 2.6.1.13). It is observed that Se enhances the ability of M. robusta to withstand Mn stress by regulating polyamine and proline metabolism, thereby highlighting a possible mechanism for reducing Mn toxicity in plants.

Abiotic stress, particularly heat and drought, significantly impacts plant reproductive development, threatening crop productivity and food security. Understanding stress tolerance mechanisms requires a multi-level approach that integrates physiological, biochemical, and molecular traits in different experimental settings. This review explores key methodologies for assessing resilience to single and combined abiotic stress in reproductive tissues, from growth chamber experiments to greenhouse and field trials. Essential physiological and biochemical traits indicative of stress responses are highlighted alongside molecular pathways that provide deeper insights into adaptation to drought and heat stress. The use of multi-omics techniques, including transcriptomics, proteomics, and metabolomics, as powerful tools for identifying novel stress-associated traits is discussed, with an emphasis on the integration of these techniques into a holistic framework, which also incorporates single-cell approaches. Finally, we address the limitations of the current methodologies and propose future research directions to improve stress resilience assessment in plant reproductive development.

Increasing soil salinization poses a severe threat to global agricultural production. Quercetin, a natural compound known to effectively alleviate abiotic stress, has an unclear molecular regulatory mechanism in enhancing soybean salt tolerance. To investigate its mechanism of action, this study established control, quercetin treatment, salt stress, and quercetin plus salt stress groups. By integrating physiological indices with transcriptomic and metabolomic analyses, we systematically elucidated the molecular mechanisms by which exogenous quercetin enhances salt tolerance in soybeans. The results demonstrated that quercetin treatment not only significantly improved root growth and ionic homeostasis (increased K⁺/Na⁺ ratio) under salt stress but also enhanced energy supply by reinforcing sucrose metabolism and the tricarboxylic acid cycle. Furthermore, it coordinately regulated key genes in the abscisic acid and jasmonic acid signaling pathways to bolster stress responses, while simultaneously promoting proline accumulation and reprogramming the flavonoid metabolic pathway. Thereby, a multifaceted regulatory network for salt tolerance was constructed. This study provides new insights into the role of quercetin in plant stress resistance and offers a theoretical basis for crop breeding for improved stress tolerance.