Plant Cell Reports最新文献

Key message: SnRK1 response and cellular energy status are evaluated using a novel N/ER index, which reflects changes in the intracellular distribution of its catalytic subunit, SnRK1.1. Maintaining energy homeostasis is a major challenge for plants facing changes in growth conditions. The Sucrose non-Fermenting 1 (SNF1) Related Kinase 1 (SnRK1) complex is a central player in securing cell energy homeostasis. The α subunit of this complex, also known as SnRK1.1, is a protein kinase that plays a critical role in sensing energy status and coordinating metabolic reprogramming to counter any energy imbalance. The discovery of a dual and dynamic intracellular distribution of SnRK1.1 suggests that its activity and function might be regulated by spatiotemporal changes. To investigate the link between the spatiotemporal localization of SnRK1.1 and SnRK1 response, we developed a protocol to quantify its intracellular distribution. We conceptualized and defined a new parameter, the N/ER index, which quantifies changes in distribution between nuclear and non-nuclear SnRK1.1 fractions. Using fluorescence confocal images acquired along the z-axis in plants expressing SnRK1.1-eGFP, and the open-source software Fiji/ImageJ, we calculated this parameter under control conditions and in plants treated with DCMU, a well-known trigger of SnRK1 response. These results showed that changes in SnRK1.1 intracellular localization constitute a major mechanistic step in the SnRK1-mediated response to restore energy homeostasis in planta. In addition, we establish the compatibility of our robust and simple method with a commercial software-based approach with different segmentation and quantification tools. Finally, our work demonstrates that N/ER index serves as a readout of SnRK1 response cell energy levels.

Key message: This study promotes AaTPS3-mediated caryophyllene synthesis by negatively regulating AaWRKY1/2 under low-phosphorus conditions, and enhances Artemisia argyi quality via appropriate phosphorus fertilizer application. Artemisia argyi (A. argyi), a plant species within the Asteraceae family, is extensively applied in pharmaceuticals, dietary therapy, and cultural practices. Caryophyllene, its primary bioactive compound, exhibits mosquito-repellent, analgesic, and anti-inflammatory activities. While there are preliminary understandings of the caryophyllene biosynthesis pathway in A. argyi, the functional characterization of critical synthases and the regulatory effects of environmental factors on caryophyllene accumulation remain incompletely understood. Phosphorus (Pi), an essential element for plant growth, plays an unclear role in regulating A. argyi development and caryophyllene metabolism at the molecular level. In this study, we treated A. argyi with varying phosphorus concentrations, measuring growth parameters, morphological changes, and yield of A. argyi. Under low-phosphorus (NKP_1/5) treatment, the contents of caryophyllene (in volatile oil and fresh leaves), soluble sugar, soluble protein, root activity, chlorophyll content, and total flavonoids of mugwort were notably higher than those under normal phosphorus (NKP₁) treatment, while the fluff rate and yield showed no significant differences between the two treatments. Low phosphorus promoted the content of caryophyllene and the expression of terpene synthase gene (AaTPS3). We also identified two low-phosphorus-responsive transcription factors AaWRKY1 and AaWRKY2, which negatively regulate the transcription of AaTPS3. The content of caryophyllene in A. argyi overexpressing AaWRKY1/2 decreased significantly. The above results uncover the molecular mechanism by which low phosphorus promotes caryophyllene synthesis through the "AaWRKY1/2-AaTPS3" pathway. It fills a research gap in the relationship between phosphorus and caryophyllene biosynthesis in A. argyi and provides a theoretical foundation for optimizing phosphorus management and enhancing A. argyi quality.

Key message: GABA enhanced Al tolerance in broad bean through reducing Al accumulation by fine-tuning transport genes, reinforcing transcriptional activation of lignin biosynthesis, and enhancing internal detoxification by reconfiguring (iso)flavonoid biosynthesis. Aluminum (Al) toxicity is recognized as the second largest abiotic factor that limits crop productivity worldwide. While γ-aminobutyric acid (GABA) is known to enhance plant stress tolerance, its role in Al resistance, particularly in legumes like broad bean (Vicia faba L.), remains poorly understood at the molecular level. This study integrated physiological and transcriptomic analyses to elucidate the mechanisms by which exogenous GABA alleviates Al toxicity in broad bean. Results showed that 1000 μM GABA significantly mitigated Al-induced root growth inhibition. Crucially, GABA reduced root and shoot Al concentrations by 52.0% and 55.2%, respectively, which was linked to the upregulation of VfALMT1 (mediating Al efflux) and downregulation of VfNIP1;2 (mediating Al root-to-shoot translocation). Concurrently, GABA alleviated the Al-induced suppression of lignin biosynthesis, reinforcing the cell wall as a physical barrier. Furthermore, GABA synergistically amplified the flavonoid biosynthesis pathway and uniquely activated the Al-suppressed isoflavonoid biosynthesis pathway, enhancing antioxidant capacity and potentially internal detoxification. These findings demonstrate that GABA enhances Al tolerance not by simply reversing Al-induced changes but by actively reprogramming key processes, including Al transport, cell wall fortification, and secondary metabolism. This study provides novel insights into GABA's multifaceted role as a signaling molecule in plant Al stress tolerance, offering potential strategies for improving crop resilience in acid soils.

Key message: Solanum lycopersicum SlMYB2 enhances drought, salt, and cadmium stress tolerance by upregulating stress-responsive genes, improving proline levels and antioxidant activity, and reducing oxidative damage. MYB transcription factors are widely present in plants and play critical roles in regulating responses to abiotic stresses, yet most remain poorly characterized. In this study, a typical R2R3-MYB gene (SlMYB2) from Solanum lycopersicum was isolated and identified, and its role in abiotic stress response was investigated. Stress-related cis-acting elements were present in the promoter sequence of SlMYB2, such as drought response elements, low-temperature response elements, and ABA response elements. Subcellular localization analysis showed that SlMYB2 is localized in the nucleus. Transactivation activity assay in yeast cells revealed that SlMYB2 has transactivation activity, and its active domain is located in the C-terminal. Drought, salt, and cadmium stress resulted in a rapid induction of SlMYB2 expression in tomato. Furthermore, compared to wild-type plants, SlMYB2-overexpressing Arabidopsis thaliana showed a higher seed germination rate and cotyledon greening rate, along with significantly increased proline content, chlorophyll levels, and peroxidase activity under drought, salt, and cadmium stress. In contrast, the transgenic lines exhibited a significantly lower malondialdehyde content than the wild-type. Expression analysis demonstrated that SlMYB2 overexpression upregulated key drought-, salt-, and cadmium-responsive genes under stress conditions, supporting its central role in the transcriptional regulation of integrated multi-stress tolerance in plants. These results indicated that SlMYB2 acts as a positive regulator in enhancing plant tolerance to drought, salt, and cadmium stress.

Key message: Bioinformatics analysis revealed 39 TIFY genes in two Medicago species, with MsTF2 significantly improving abiotic stress tolerance in both prokaryotic and eukaryotic cells. Transcription factor (TF) serves as crucial regulatory proteins in eukaryotes, facilitating RNA polymerase's ability to initiate transcription at particular promoter regions. TIFY proteins are crucial for plant growth and development, as well as signal transduction and stress responses. The TIFY gene family plays crucial roles in stress responses in higher plants, yet comprehensive studies on this protein family in Medicago species remain unexplored. The study identified 39 TIFY genes, comprising 19 in Medicago sativa and 20 in Medicago truncatula, which were unevenly distributed across their respective eight chromosomes. Synteny analysis indicated that tandem and segmental duplications were the primary drivers of TIFY family expansion in these two species. Promoter cis-element analysis revealed an enrichment of stress-responsive motifs, suggesting their functional involvement in abiotic stress adaptation. Transcriptomic and RT-qPCR analyses demonstrated that most TIFY members exhibited strong induction under drought, cold, and high-salinity conditions. Notably, MsTF2, a nuclear-localized protein, displayed the most pronounced stress-responsive expression among all examined TIFY genes. Heterologous expression of MsTF2 in both prokaryotic and eukaryotic systems conferred significant enhancement of tolerance to drought, extreme temperature, and high-salinity stresses. These findings provide a molecular framework for understanding MsTF2-mediated stress resistance and highlight potential genetic targets for improving abiotic stress resilience in Medicago through molecular breeding strategies.

Key message: The AtVIP1-SbARF7 module controls root development via auxin signaling, offering insights into root regulatory networks and crop improvement. Plant root development is regulated by the auxin signaling pathway. It has been found that AtVIP1 (Arabidopsis thaliana VirE2-interacting Protein 1) gene overexpression promotes lateral root growth in sorghum, but its mechanism of action is not clear. The purpose of this study is to analyze the molecular mechanism by which AtVIP1 regulates sorghum root development through the auxin pathway, By constructing AtVIP1 overexpressing and silencing lines, it was found that overexpressing plants had a more developed root system (increased number of lateral root primordia and increased root volume), whereas silencing lines had suppressed growth. Expression analysis showed that AtVIP1 was enriched in root tips and lateral root primordia with subcellular localization in the nucleoplasm. Hormone treatment confirmed that AtVIP1 promoted auxin accumulation through the IAA pathway and stably up-regulated the expression of downstream genes such as SbYUCCA2 and SbIAA14. Y1H and EMSA confirmed that AtVIP1 directly binds to the SbARF7 promoter. The Dual-Luciferase Reporter constructed shows that AtVIP1 increases the promoter activity of SbARF7 by 2.3 times. After silencing SbARF7 in the background of AtVIP1-OE, the root branches decreased, indicating that AtVIP1 promotes root development by activating SbARF7 transcription. This study reveals the molecular mechanism by which the AtVIP1-SbARF7 module regulates root development through the auxin signaling pathway, providing new insights into the transcriptional regulatory network of root development and potential targets for the genetic improvement of crop root traits.

Key message: ZmDRZ1 serves as a negative regulator of drought tolerance in maize seedlings by modulating stomatal closure through an ABA-dependent signaling pathway. Drought is one of the major risk factors for maize (Zea mays L.) yield. Some genes controling drought resistance have been cloned, but the role of drought resistance is still not clear in maize. The RING (Really Interesting New Gene) domain-containing protein family plays critical role in abscisic acid (ABA) signaling pathways that orchestrate plant responses to abiotic stress. Here, we characterized the RING protein family of maize and identified a novel RING-v gene, designated drought-related RING Zinc finger 1 (ZmDRZ1). Tissue-specific expression analysis indicated that ZmDRZ1 expression was significantly down-regulated in maize seedlings under drought conditions. CRISPR/Cas9-mediated knockout of ZmDRZ1 enhanced drought resistance by increasing ABA content, promoting stomatal closure, and improving photosynthetic performance. Conversely, ZmDRZ1- overexpression (OE) lines exhibited reduced relative water content, elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), and increased sensitivity to drought stress. Further investigation showed that ZmDRZ1 regulates key ABA-related drought resistance genes, including ZmPP2C80, ZmPP2C30, and ZmCYP707As, which are involved in ABA signal transduction and degradation, respectively. In conclusion, our findings indicate that ZmDRZ1 modulates drought resistance in maize through an ABA-dependent pathway. These findings provide insights for further elucidating the ZmDRZ1-mediated mechanisms underlying drought responses in maize.

Transcription factors (TFs) are central regulators of plant life activities. Trihelix transcription factors, a plant-specific family characterized by a conserved trihelix (helix-loop-helix-loop-helix) DNA-binding domain, play essential roles in modulating plant growth, development, and stress responses. This review systematically outlines the structural characteristics and phylogenetic classification of trihelix transcription factors, with a particular emphasis on their multifaceted regulatory functions during the development of seeds, fruits, leaves, flowers, and roots. We also provide a deep analysis of the molecular mechanisms by which trihelix members mediate responses to abiotic stresses (e.g., drought, salinity, temperature extremes, and hypoxia) and biotic stresses (e.g., pathogen infection). Critically, we synthesize emerging evidence into core regulatory pathways, illustrating how key trihelix factors such as GTL1 function as central nodes that coordinate antagonistic processes like growth, stress adaptation, and immunity. Finally, we highlight unresolved key questions in the field and suggest future research directions, aiming to establish a theoretical foundation for further functional exploration and agricultural utilization of trihelix transcription factors.

Key message: The rice pollen-specific calmodulin-like protein OsCML17 contributes to fertilization by regulating pollen germination and pollen tube elongation, and is localized to the endoplasmic reticulum and plasma membrane. In angiosperms, successful fertilization relies on the precise growth of the pollen tube growth. Calcium ion (Ca²⁺) regulates various physiological responses and plays a critical role in pollen germination and pollen tube growth. Calmodulin-like proteins (CMLs), which consist of EF-hand motifs, function as Ca²⁺ sensors that detect changes in intracellular Ca²⁺ concentrations and regulate specific signaling pathways. Despite their significance, the expression dynamics and functional significance of CMLs in rice remain largely unexplored. In this study, we examined expression profiles and structural properties of 32 CML genes in rice to identify those preferentially expressed in pollen. OsCML17 exhibited strong expression in rice mature anthers containing tricellular pollen and was localized to both the endoplasmic reticulum and the plasma membrane in the tobacco cells. Knockout mutants of OsCML17 generated by CRISPR/Cas9 exhibited consistently reduced pollen germination rates and shorter pollen tubes. Moreover, the OsCML17 transcript was markedly decreased in the mature pollen of the madstri mutant, indicating potential transcriptional regulation by MADS-box factors. Overall, these findings suggest that OsCML17 functions as an important factor regulating pollen germination and tube elongation in rice.

Key message: Bacillus velezensis D103 improves drought tolerance through enhanced antioxidant activity and lignin deposition, with VIGS analysis indicating roles for ZmAPX3, ZmAOX1B, ZmPER72, and ZmPRX74. Drought stress is a major abiotic constrain on global crop productivity. The application of plant growth-promoting rhizobacteria (PGPR) offers a promising strategy to enhance plant drought tolerance, yet the associated molecular mechanisms remain incompletely characterized. In this study, we examined the role of Bacillus velezensis D103 in maize drought responses by assessing physiological and transcriptomic changes. Under drought stress, D103 inoculation supported plant growth and increased leaf relative water content (RWC), reducing the RWC deficit from 12.4% to 5.1%. This response was accompanied by greater lignin deposition (28.5%) and higher antioxidant enzyme activities. Transcriptome data showed that D103 treatment activated key drought-associated pathways, including glutathione metabolism and phenylpropanoid biosynthesis. VIGS assays suggested that ZmAPX3 (glutathione metabolism), ZmAOX1B (ROS-scavenging), and ZmPER72 and ZmPRX74 (phenylpropanoid metabolism) contribute to the drought tolerance observed in D103-treated plants. Overall, the findings suggest that B. velezensis D103 supports maize drought tolerance by regulating lignin biosynthesis and ROS-related processes. This study provides insights into PGPR-mediated stress resistance responses and highlights strain D103 as a candidate microbial inoculant for improving crop performance under water-limited conditions.