Plant Cell Reports最新文献

Key message: SmMYC2 promotes SmNST1 expression and inhibits the expression of SmMYB108 and SmMYC2 itself in vivo, then thickens secondary cell wall and enhances drought resilience of eggplant. As climate change worsens, drought stress has emerged as a critical limiting factor for crop productivity. Members of the basic helix-loop-helix (bHLH) transcription factor family exhibit multifunctional regulatory roles in plant adaptation mechanisms. Nevertheless, the operational dynamics of bHLH-mediated genetic networks in Solanum melongena L. during water deficit conditions remain poorly characterized. This study focused on the molecular characterization of SmMYC2, a nuclear-localized bHLH transcription factor isolated from 'March eggplant' cultivar. Tissue-specific expression profiling revealed predominant transcript abundance in foliar tissues in comparison with other organs. Transgenic overexpression lines showed higher tolerance under drought treatment by increasing SOD content and decreasing MDA content with no significant change in POD activity in comparison with WT (wild-type) plants. Notably, SmMYC2-OE plants displayed significant stem diameter enlargement. In vivo protein interaction analyses employing bimolecular fluorescence complementation and luciferase-based imaging confirmed physical associations between SmMYC2 and SmJAZ1/SmJAZ3/SmMYB21. Functional genomic investigations through yeast one-hybrid systems and luciferase reporter analyses uncovered an autoregulatory mechanism where SmMYC2 binds to its autologous promoter to suppress transcriptional activity. Furthermore, SmMYC2 demonstrated differential regulatory effects by suppressing SmMYB108 promoter activity. Although SmMYC2 did not directly bind the SmNST1 promoter in vitro, it altered ProSmNST1 activity in vivo, suggesting an indirect regulatory mechanism. This comprehensive analysis reveals that SCW structural reinforcement correlates with improved drought adaptation in eggplant, elucidating a multilayered transcriptional framework with potential applications in eggplant productivity enhancement.

Key message: Melatonin enhances rice's stress resilience by altering stress responses through molecular mechanisms, suggesting innovative strategies for sustainable agriculture amid biotic and abiotic stressors. Melatonin, a well-known mammalian hormone, is a multifunctional regulator of plant growth, development, and adaptation to stressors. Rice (Oryza sativa L.) yields are under pressure from both biotic and abiotic challenges, which demand robust agricultural practices to ensure food security. Melatonin has attracted considerable attention in rice, owing to its ability to enhance tolerance to diverse abiotic and biotic stressors. Despite significant progress, the molecular and cellular mechanisms underlying melatonin-mediated stress response in rice remain poorly understood. This review summarizes current insights into melatonin biosynthesis, signal transduction, and cross-regulatory networks that coordinate its actions in rice. Particular emphasis is placed on the role of melatonin in mitigating abiotic stresses, such as drought, salinity, extreme temperature, and heavy metal toxicity, as well as strengthening biotic stress tolerance through the modulation of immune signaling and pathogen defense pathways. In addition, we discuss the emerging applications of melatonin-based nanotechnologies, which offer tailored dispersion and sustained bioavailability, as promising tools for enhancing stress resilience in rice. By integrating molecular understanding with nanobiotechnology, this review offers a comprehensive update on the dynamic role of melatonin in the regulation of rice stress. Future research should prioritize unraveling cross-regulatory pathways, along with genetic and biotechnological strategies, to fully exploit the defense potential of melatonin to improve rice productivity and agricultural sustainability under adverse conditions.

The bigleaf hydrangea (Hydrangea macrophylla) is an emerging fashionable flower. However, leaf spot disease caused by Corynespora cassiicola is a major fungal disease in this species, seriously limiting the high-quality development of the industry. Since potential C. cassiicola induced genes have been identified via RNA-seq data, we aimed to develop an efficient method to screen C. cassiicola resistant genes in hydrangea. Firstly, we established a C. cassiicola inoculation system for detached leaf discs (CISDLD) and applied it to assess leaf spot resistance in hydrangea cultivators. Then, HmPDS1 and HmPDS2 were selected as the reporter genes to test the silencing effect in both cuttings and detached leaf discs, through observing a significant reduction in gene expression and chlorophyll content. Furthermore, ethylene was identified as a positive regulator in hydrangea defense responding to C. cassiicola, as well as jasmonic acid. The results showed that ethylene synthesis genes (HmACS1 and HmACO3) and signaling transduction genes (HmEIN3 and HmERF001) were validated as the C. cassiicola resistant genes in hydrangea. The VIGS screen of C. cassiicola-induced ethylene related genes demonstrated the potential benefits of this method for the high-throughput identification of gene function. This study offers a rapid approach for characterizing C. cassiicola-related gene functions in hydrangea and provides a theoretical framework for high-throughput gene screening in other plant species. KEY MESSAGE: A rapid and effective method for gene function screening based on VIGS with detached leaf discs reveals the crucial role of ethylene in hydrangea leaf spot resistance.

Key message: Transcriptomic analysis revealed that GmERF1 expression is induced by Phytophthora sojae and positively regulates soybean resistance to P. sojae via salicylic acid signal transduction pathway. Soybean (Glycine max) root rot caused by Phytophthora sojae is a major disease constraining the global soybean industry. Therefore, improving crop resistance to this pathogen remains a key objective in breeding efforts. However, the mechanisms by which soybeans respond to P. sojae infection, as well as the specific regulatory networks of key transcription factors (TFs), remain to be elucidated. Here, we report that Ethylene Response Factor 1 (GmERF1), encoding an AP2/ERF transcription factor, exhibits significant differences in expression between resistant and susceptible soybean cultivars. Molecular evaluation and disease resistance analysis show that GmERF1 could improve soybean resistance to P. sojae. Further transcriptomic analysis and quantitative analysis of salicylic acid (SA) signal transduction genes indicate that GmERF1 could positively regulate the expression of Non-expressor of Pathogenesis-Related genes 1 (GmNPR1), TGACG sequence-specific binding factor (GmTGA) and Pathogenesis-Related gene 1 (GmPR1). Taken together, these results suggest that GmERF1 positively regulates soybean resistance to P. sojae by enhancing SA signaling, providing novel insights into soybean resistance to Phytophthora root rot.

Key message: The overexpression of VlPAT2 enhances the resistance of grapevine and Arabidopsis thaliana to Botrytis cinerea, and promotes the accumulation of reactive oxygen species, as well as the expression of multiple PR genes and R genes. Grape grey mould caused by the necrotrophic fungus Botrytis cinerea causes severe economic losses to the grape industry. Identifying disease resistance genes and elucidating their mechanisms provide critical insights for molecular breeding. Here, we report a GRAS family transcription factor VlPAT2 from the grapevine cultivar 'Beta' (Vitis labrusca) that exhibits high resistance to B. cinerea, which is involved in positively regulating grape resistance to this fungal pathogen. The VlPAT2 expression is responsive to treatments of salicylic acid, ethephon, bacterial flagellin peptide flg22, and hydrogen peroxide (H₂O₂). Overexpression of VlPAT2 in grapes and Arabidopsis thaliana can enhance resistance to B. cinerea, accompanied by the accumulation of reactive oxygen species (ROS). In addition, the transcriptional levels of salicylic acid signalling-associated defence genes (PR1 and PR5) and multiple resistance genes (R genes) were significantly upregulated in VlPAT2-overexpressing grape leaves. In conclusion, our findings indicate that the transcription factor VlPAT2 enhances disease resistance in grapevines and provides a gene source for the molecular breeding of grape varieties resistant to B. cinerea.

Key message: RNAi mediated combinatorial silencing of StUGPase and StVInv genes in potato demonstrated significant reduction of sucrose and reducing sugar accumulation after cold storage with improved chipping quality. Potato (Solanum tuberosum L.) is stored in cold conditions after harvest to maintain year-round availability by preserving its physiological vigour and preventing rotting. However, cold storage of potato leads to cold-induced sweetening, an undesirable physiological pathway of breakdown of starch into reducing sugars (RS), primarily glucose and fructose. These RS react with free amino acids at high temperature, producing dark, bitter-tasting products due to non-enzymatic Maillard reaction, rendering the tubers unsuitable for processing. UDP-glucose pyrophosphorylase (StUGPase) and vacuolar acid invertase (StVInv) are the two key enzymes that play central roles in the CIS pathway. To mitigate CIS, a combinatorial RNA interference (RNAi) approach was adopted to simultaneously silence both genes. A hairpin RNA (hpRNA) construct, CISCOM, was designed by fusing cDNA fragments of StUGPase and StVInv in sense and antisense orientations, separated by the potato GBSS intron. CISCOM transgenics of two Indian cultivars of processing quality, Kufri Chipsona-1 (KC1) and Kufri Chipsona-3 (KC3), demonstrated significantly low sucrose and RS accumulation following one month of cold storage at 4 °C due to many folds reduction at the transcript level and activities of both the enzymes. Chips produced from cold-stored RNAi potato tubers were lighter in colour, as acceptable by processing standards, compared to those from non-transgenic controls, which were unacceptably dark brown in colour. The study highlights the potential of combinatorial RNAi as an effective strategy to ameliorate cold-induced sweetening and much needed boost to the potato processing sector.

Key message: We resolved that SlMYC2 positively regulated tomato leaf senescence by inhibiting ROS scavenging capacity and exacerbating oxidative damage and PSII functional decline using a darkness-induced senescence model. Tomato leaf senescence seriously affects its yield and quality. Jasmonic acid (JA) signaling can promote tomato leaf senescence, but the mechanism is unclear. SlMYC2, as a core transcription factor in JA signaling, may play a role in regulating leaf senescence. Therefore, this study used SlMYC2 overexpression and silencing lines to systematically analyze the mechanism of SlMYC2 regulation of leaf senescence through a darkness-induced senescence model. The results showed SlMYC2 accelerated the leaf senescence process in tomato by increased chlorophyll degradation and malondialdehyde accumulation in SlMYC2-OE lines after dark treatment, and the expressions of senescence-related genes SlSGR1, SlSAG12, and SlSAG15 were significantly upregulated. At the photosynthetic physiological level, SlMYC2-OE caused damage to photosystem II (PSII) function, with a significant decrease in maximum photochemical efficiency (F_v/F_m) and performance index (PI_ABS), and exacerbated damage to the donor side (W_k). Further studies found SlMYC2 accelerated programmed cell death (PCD) by promoting the accumulation of reactive oxygen species (ROS). The contents of superoxide anion (O₂^⁻·) and hydrogen peroxide (H₂O₂) significantly increased in the SlMYC2-OE lines, while the contents of ascorbic acid (AsA) and glutathione (GSH), as well as the activities and gene expressions of key antioxidant enzymes such as SOD, POD, CAT, APX, and GR were all inhibited. In summary, SlMYC2 has been shown to inhibit the removal of reactive oxygen species (ROS), exacerbate oxidative damage and photosystem II (PSII) function decline, and positively regulate the process of leaf senescence in tomato. This study will provide a theoretical foundation for targeting the JA signaling pathway to regulate tomato senescence.

Key message: The present study demonstrates the first CRISPR/Cas-mediated precise knock-in of the eGFP gene at the BABYBOOM2 (GN-BBM2) locus in banana cv. Grand Naine, facilitating the detection of editing events in early embryogenic developmental stages. Genome editing has accelerated crop improvement programs by introducing targeted and precise genetic modifications. Among different tools, CRISPR/Cas-based genome editing has been widely used for enabling mutations through double-stranded breaks (DSBs), repaired either by non-homologous end joining (NHEJ) for gene knockouts or homology-directed repair (HDR) to generate knock-in events. While gene knockouts are well established in banana, efficient knock-in remains a major challenge due to low HDR activity, sterility, and the vegetatively propagated nature of banana. In the present study, we report the first successful CRISPR/Cas-based gene knock-in editing in banana by targeting the BABYBOOM2 (BBM2) gene, which encodes a transcription factor involved in somatic embryogenesis. The enhanced green fluorescent protein (eGFP) gene was precisely inserted at the BBM2 locus in banana cv. Grand Naine to enable visual detection during embryogenesis. In vitro validation showed ~ 95% target cleavage efficiency of the selected gRNA. The PCR-based screening and shift-in amplicon size analyses confirmed three edited lines (#3, #11, and #14) harboring eGFP knock-in at the targeted locus. Sequencing of the amplicon from these lines further confirmed the precise knock-in events. Hence, this study establishes a foundation for precise knock-in-based genome modification in banana and opens new avenues for targeted trait improvement in this important clonally propagated crop.

Key message: This study uncovers a temperature-mediated, localized auxin status perturbation in the meristem region responsible for root growth suppression under elevated temperature environments, revealing novel insights into root-environment interactions. Agriculture is highly sensitive to weather and climate because of its heavy reliance on temperature, water, and other natural resources. Among these variables, plants are particularly susceptible to changes in ambient temperature due to its influence on growth and development throughout the life cycle. Therefore, global warming presents a fundamental threat to plant life and productivity. As this climate crisis worsens, it is critical to deepen our understanding about the adverse impacts of elevated temperature on aspects of plant development. In this study, we investigate the negative influence of a rising temperature environment on root system attributes. Compared to the shoot system, roots are known for higher thermosensitivity. Here, our findings demonstrate that besides growth, multiple root system aspects, such as gravitropism response, root system architecture, etc., are affected by elevated temperature environments. Root meristem activities appear to be highly auxin-dependent in a rising temperature environment compared to ambient growth conditions. Furthermore, our findings demonstrate a disruption in auxin status within the root meristem region, in plants exposed to elevated temperature. This temperature-mediated, localized perturbation in the auxin pathway contributes to defective cell proliferation activities and culminates in root growth suppression under elevated temperature. Collectively, these findings provide novel insights into the interplay between root system traits and a rising temperature environment.

Key message: SNFE framework identifies 10 key CTgenes and reveals novel cold-tolerance mechanisms in soybean. Cold stress poses a significant threat to soybean (Glycine max (L.) Merr) productivity, during early developmental stages. Traditional approaches for identifying cold-responsive genes have been limited by size bias, pathway redundancy, and lack of integrative validation. To address these challenges, we developed a multi-layered systems biology framework, termed SNFE (systems and network-based feature engineering), to uncover key cold-tolerant genes (CTgenes) by leveraging both panomics and non-omics data in a network-informed context. The SNFE framework integrates five analytical layers: functional pathway enrichment, pathway crosstalk, co-functional network construction, network topology analysis, and experimental validation. From an initial pool of cold-responsive genes, SNFE identified 10 key CTgenes demonstrating high connectivity, regulatory importance, and consistent differential expression in short- and mid-term cold conditions. These genes were validated via independent transcriptomic datasets, Quantitative real-time PCR analysis, and hormone profiling. Notably, SNFE revealed novel regulatory mechanisms, including dual-timed transcription factors, ABA-JA hormone synergy in membrane stabilization, and convergence of abiotic and biotic stress signaling. A Sankey diagram and volcano plot further confirmed that most CTgenes reside at key regulatory nodes, linking upstream functions to downstream cold-tolerance pathways. SNFE is a reliable, efficient, and interpretable tool that not only improves prediction accuracy but also enables the discovery of novel biological insights. Its scalability and analytical depth make it a powerful platform for dissecting complex stress responses in crops. This framework provides a strategic foundation for molecular breeding; we also discuss the potential of multiplex "full gene packages" as a downstream engineering avenue to enhance cold resilience.