生命科学最新文献

Plants growing in nature are exposed to multiple abiotic and biotic stressors that sometimes occur sequentially. We hypothesised that drought will not compromise the resistance levels to herbivores when plants are associated with Epichloë endophytes able to produce bioactive alkaloids. Lolium perenne plants without (nil) and with Epichloë LpTG-3 sp. strain AR37 able (wild type (wt), ∆idtA) and unable (∆idtM) to produce indole diterpene alkaloids were subjected to a drought treatment followed by a challenge with Rhopalosiphum padi aphids at drought recovery. Drought increased the susceptibility to aphids in both nil and ∆idtM-associated plants, whereas it did not affect the aphid resistance in wt-associated plants. Drought increased the aphid resistance in ∆idtD-associated plants, a response that was related to a drought-mediated increase in concentrations of some AR37-derived alkaloids. The negative effects of drought on plants were alleviated through the AR37 symbiosis via host growth promotion associated with increased concentrations of drought protective phytohormones and amino acids (e.g., abscisic acid and proline), and enriched abundance of bacteria belonging to Agrococcus, Chryseobacterium, and Parcubacteria that contain members providing stress protective traits. Our study highlights the key role of endophytes in increasing the performance of plants challenged by abiotic and biotic stressors.

Plants produce broad spectra of metabolites comprising primary metabolites involved in core physiological processes and specialized metabolites mediating responses to biotic and abiotic stress. Understanding how these various components of the metabolome respond to different environmental pressures can help us to understand drivers of phytochemical diversity and its role in plant ecology and evolution. We investigated how climatic stress, soil resources, and herbivory influence various measures of phytochemical diversity in four willow species along an elevational gradient (950-2250 m a.s.l.), focusing on flavonoids, salicinoids, and primary metabolites. Harsher climates increased metabolite concentrations, particularly salicinoids, but reduced flavonoid richness and overall structural α-diversity. Similar responses in primary metabolites suggest that these shifts extend beyond defence chemistry. Chemical properties showed the strongest shifts in flavonoids and salicinoids and weaker changes in primary metabolites. β-diversity generally increased with elevation and was most strongly associated with climate, while soil nutrients contributed to shifts in β-diversity of salicinoids and primary metabolites. Willow species showed weak genetic differentiation across elevation, suggesting limited population divergence. Together, these results indicate that elevational shifts in willow chemistry involve broad but uneven reorganization across the metabolome, with different metabolite groups and measures of diversity plastically responding to different drivers.

Berry cracking is a severe physiological disorder that compromises quality and causes economic losses in grapes. Despite recent research progress, current knowledge offers limited insight into the molecular pathways. This study shows that gibberellin (GA₃) effectively mitigates berry cracking in the susceptible cultivar 'White Munake' by modulating cell wall remodeling processes. Multi-omics analysis revealed that GA₃ treatment significantly alters key pectin-modifying enzymes and cell wall related pathways. Results showed that VviPME39, which encodes a pectin methylesterase, facilitates the maintenance of cell wall structure. Functional validation through heterologous overexpression in tomato confirmed that VviPME39 enhances fruit cracking susceptibility and reduces firmness. Furthermore, we identified VviWRKY50 as a transcriptional repressor that directly binds to the VviPME39 promoter and inhibits its expression, proposing a potential novel GA₃-VviWRKY50-VviPME39 regulatory module. This pathway operates independently of ethylene-mediated softening mechanisms reported in other species, revealing a unique hormonal regulatory strategy in grape. Our study showed fundamental insights into the molecular mechanism of berry cracking and identified possible targets for breeding crack-resistant grape varieties through manipulation of the VviWRKY50-VviPME39 regulatory mechanism.

Aluminium (Al) toxicity severely limits crop productivity in acidic soils by inhibiting root growth and nutrient uptake, yet the hormonal mechanisms coordinating Al defence in tobacco remain unclear. Here, we show that Al stress rapidly induces gibberellin (GA) biosynthesis in tobacco roots, and that GA signalling mitigates Al toxicity by promoting root growth and reducing Al accumulation. Using exogenous GA application, CRISPR/Cas9-mediated NtGA3-ox1 mutants, GA biosynthesis inhibitors, transcriptomic profiling, and biochemical analyses, we demonstrate that GA enhances Al exclusion through two complementary mechanisms: remodelling root cell wall composition, particularly by increasing hemicellulose content to sequester Al, and reinforcing the endodermal Casparian strip (CS) through the upregulation of CS-associated genes. Pharmacological manipulation of lignin biosynthesis confirms that early CS formation was critical for restricting Al entry. These findings reveal GA as a dynamic regulator of Al stress adaptation, coordinating structural and biochemical defences to maintain root growth, and highlight GA signalling as a potential target for improving crop tolerance to Al-toxic acidic soils.

Cuticular waxes, together with cutin, form a hydrophobic barrier that protects the plants against various biotic and abiotic stresses. The past decade has seen remarkable progress in deciphering the wax biosynthesis and transport, however, the continuous discovery of wax-defective mutants and the development of diverse technologies are progressively refining our current understanding of wax biosynthetic pathways. Here, we provide a comprehensive summary of the biosynthetic pathway and transport mechanisms of plant cuticular waxes, with a particular emphasis on recent breakthroughs, including the carbon reallocation mechanism between the alkane-forming and alcohol-forming pathways, as well as the emerging branched-chain wax biosynthesis pathway. We also review how wax synthesis responds to diverse abiotic stresses, including salt, extreme water conditions and temperature, light, and outline critical knowledge gaps that remain to be addressed, including the wax biosynthesis in non-model plants, the physiological function of branched wax and their underlying molecular mechanisms.

Temperate ring-porous tree species are more vulnerable to freezing-induced embolism than their diffuse-porous counterparts due to their large earlywood vessels. Although ring-porous species can restore hydraulic function by forming earlywood vessels in early spring, they may face high risk of embolism during spring frosts. Here, we tested the hypothesis that ring-porous temperate trees employ a strategy of enhanced freezing avoidance to protect their vulnerable earlywood vessels from the risk of freezing-induced embolism. We quantified the degree of embolism in overwintering stems, ice nucleation temperature (INT_xylem), water content (WC_xylem), and non-structural carbohydrate (NSC) concentrations in stem xylems of 20 temperate tree species (nine diffuse-porous and 11 ring-porous) grown in a common garden. Consistent with our hypothesis, ring-porous species suffered severe embolism over the winter and exhibited stronger freezing avoidance during spring. While diffuse-porous species rely on smaller vessels to resist freezing-induced embolism, ring-porous species showed stronger ability of freezing avoidance by lowering INT_xylem via reduced WC_xylem and higher NSC concentrations. This strategy likely protects their vulnerable, newly developed earlywood vessels from freezing-induced hydraulic dysfunction. These findings reveal distinct strategies between temperate diffuse-porous and ring-porous species for coping with spring frost stress, providing insights into forest responses to climate change.

Cereal crops collectively account for more than half of global human caloric intake, yet the molecular mechanisms governing their root systems under water and nitrogen limitation remain poorly understood relative to their agronomic importance. The C-terminally encoded peptide (CEP) family has emerged, primarily from work in Arabidopsis thaliana and Medicago truncatula, as a class of post-translationally modified peptide hormones that coordinate nitrogen demand signalling through a root-to-shoot-to-root relay involving CEPR1 leucine-rich repeat receptor-like kinases and phloem-mobile CEPD glutaredoxins, regulate lateral root gravitropic set-point angle through integrated auxin and cytokinin pathway interactions, and contribute to abiotic stress responses through stabilisation of AUX/IAA transcriptional repressors under osmotic stress. This review synthesises CEP biology with the specific architectural and agronomic characteristics of cereal root systems, explicitly distinguishing between findings established in model dicots, evidence for receptor-ligand conservation in cereals, and mechanisms that remain untested in crops. CEPR1 orthologues in barley, maize, and rice restore wild-type phenotypes in Arabidopsis complementation assays, and CRISPR-Cas9 knockout of CEPR1 in barley confirms effects on seminal root angle, though an associated fecundity defect highlights translational complexity. Proposed connections between CEP signalling and ABA pathways remain hypothetical. In wheat, TaCEP15 modulates primary root length and drought tolerance through a receptor pathway mechanistically distinct from the canonical CEP-CEPR1-CEPD nitrogen relay, indicating functional diversification within the CEP family. Five tractable research priorities are identified, and CRISPR-based approaches, synthetic peptide application, and marker-assisted selection are discussed as near-term strategies for cereal crop improvement under drought and nitrogen-limited conditions.

The coexistence mechanisms of wide-ranging species across climate gradients are crucial for predicting their geographic range shift and community assembly. Two coexisting oaks (Quercus acutissima and Quercus variabilis) were sampled from broad-leaved forests across China. Fifteen plant functional traits related to morphology, physiology and stoichiometry were determined to assess the interspecific and intraspecific variability, trait integration and ecological strategies. Nine among the 15 studied functional traits differed significantly between the two oaks. Given all the studied traits, the two oaks exhibited similar intraspecific variability (29.0 vs. 27.9), but diverged trait-level variability, with Q. acutissima showing 13.1% lower morphological but 11.4% higher physiological variability than Q. variabilis. The connectivity and complexity within trait correlation networks of the two oaks covaried across favourable temperature ranges (ca. 15°C-20°C), but diverged below 15°C and above 20°C and along precipitation gradients. Both the oaks were clustered around competitive and stress-tolerant ecological strategies within their sampling ranges; however, Q. variabilis were more competitive but less stress-tolerant than Q. acutissima when growing at their distribution edges. Our results imply local divergent and convergent adaptation of the sympatric oaks via altering trait-level plasticity and trait integration along climate gradients, potentially leading to greater niche differentiation and complex community assembly.

Plants employ cell-type-specific transcriptional programs to defend against pathogens, yet the cellular heterogeneity of immune responses in the medicinal orchid Dendrobium officinale Kimura et Migo remains largely unexplored. A single-cell transcriptomic atlas of the D. officinale stem base upon Sclerotium rolfsii infection was constructed, profiling over 20 000 cells across 12 and 24 h post-infection. A total of 21 cell clusters were resolved into 6 major cell types-epidermal, ground tissue parenchyma, proliferating, xylem, phloem, and vascular bundle parenchyma cells-with identities validated by fluorescence in situ hybridization. Cell-type-specific analyses revealed that epidermal and phloem cells mounted early defense responses, while xylem cells exhibited the most extensive transcriptional reprogramming at 24 hpi, coinciding with the activation of lignin biosynthesis pathways. WRKY33 was identified as a central transcriptional activator that directly binds W-box motifs in the promoters of lignin biosynthetic genes C4H and HCT, promoting lignin deposition and enhancing disease resistance. Conversely, the nuclear-localized chaperone HSP81 physically interacts with WRKY33 and functions as a broad regulator of multiple transcription factors via co-factor sequestration, thereby compromising defense when overexpressed. These findings uncover a WRKY33-HSP81 regulatory module that orchestrates phenylpropanoid-mediated defense in D. officinale, providing a high-resolution cellular framework for understanding plant immunity and offering potential targets for improving disease resistance in this economically valuable species.

Alfalfa (Medicago sativa), an autotetraploid species, is a globally important forage crop. Traditional genetic transformation methods predominantly rely on leaf-derived callus, a process that is complex, inefficient, and particularly challenging to generate stable transgenic lines in polyploid plants. To address these limitations, we developed an efficient transformation system that bypasses callus induction by directly exploiting stem regeneration. Our protocol enables the generation of stable gene-edited alfalfa plants from shoot tips. It accommodates stem explants from various developmental stages and significantly reduces the time required. Moreover, this approach was effective across multiple alfalfa cultivars, and preliminary proof-of-concept experiments in Nicotiana tabacum and Solanum lycopersicum suggested potential transferability beyond alfalfa. This study represents a substantial advancement in perennial plant transformation and provides a robust and practical platform for optimizing stem regeneration-based genetic modification systems.