Stress biology最新文献

During interactions, pathogenic fungi are subjected to endoplasmic reticulum (ER) stress from the host plants, resulting in the activation of the unfolded protein response (UPR) pathway. We identified the bZIP transcription factor CfHac1 in C. fructicola, which is a pathogenic organism implicated in a variety of plant diseases, and we found it to be crucial for the ER stress response and pathogenicity. However, the role of CfHac1 in regulating the degradation of ER-associated misfolded proteins remains unclear. In this study, we discovered that the CfHAC1 gene regulates conidial production, appressorium formation, response to ER stress, and pathogenicity through unconventional splicing. Further research revealed that the CfHAC1 gene also affects the ubiquitination of ER-associated misfolded proteins and mediates their degradation. We further identified two ubiquitin ligase genes, CfHRD1 and CfHRD3, that exhibit significant down-regulation in the ΔCfhac1 mutant strain. Subsequent investigations revealed that the CfHAC1 gene affects CfHRD1 and CfHRD3 expression through unconventional splicing, with both genes managing the degradation of ER-associated misfolded proteins via ubiquitination and influencing C. fructicola pathogenicity. Taken together, our results reveal a mechanism by which the transcription factor CfHac1 affects the expression of the ubiquitin ligase genes CfHRD1 and CfHRD3, leading to the ubiquitination and degradation of ER-associated misfolded proteins and pathogenicity. This provides a theoretical basis for the development of novel agents targeting key genes within this pathway.

Trail development is more prevalent as tourism develops globally. The depth effect of trail development on plant diversity and native species' stress response via tuning flavonoids in natural ecosystems remain relatively poorly understood. We investigated the depth effects by comparing plant species diversity and flavonoid contents (of six common native species) in sampling plots plots (Rabbit Mountain Open Space, Boulder County, CO, USA) with varying distances away from trail. We found plant diversity to be lowest in plots immediately proximal to trails and highest in intermediate plots. We also found the concentrations of total flavonoids to vary significantly between plots closer and away from trails. Specifically, we found the concentrations of isoorientin and myricetin higher in plots closer to trails. On the contrary, the concentrations of vitexin and kaempferol were higher in plots away from trails. Quercetin was higher in the intermediate plots. Overall, trail development negatively impacted herbaceous plant diversity, which was evident as depth effects. The plant species responded to environmental stresses imposed by trail development through fine-tuned flavonoid accumulation.

Drought is a common environmental condition that significantly impairs plant growth. In response to drought, plants close their stomata to minimize transpiration and meanwhile activate many stress-responsive genes to mitigate damage. These stress-related mRNA transcripts require the assistance of RNA-binding proteins throughout their metabolic process, culminating in protein synthesis in the cytoplasm. In this study, we identified HLN1 (Hyaluronan 1), an RNA-binding protein with similarity to the animal hyaluronan-binding protein 4 / serpin mRNA binding protein 1 (HABP4/SERBP1), as crucial for plant drought tolerance. The hln1 loss-of-function mutant exhibited higher transpiration rates due to impaired stomatal closure, making it highly susceptible to drought. Drought stress increased HLN1 expression, and the protein underwent liquid-liquid phase separation (LLPS) to form mRNA-ribonucleoprotein (mRNP) condensates in the cytoplasm under osmotic stress. We identified GAD2 as a potential mRNA target of HLN1. GAD2 encodes the predominant glutamate decarboxylase synthesizing γ-aminobutyric acid (GABA), a non-proteinogenic amino acid that modulates stomatal movement. RIP-qPCR and EMSA showed that HLN1 binds GAD2 mRNA, which promotes HLN1 condensate formation. In hln1 mutants, GAD2 transcripts were less stable, reducing steady-state mRNA levels. As a result, hln1 accumulated less GABA and exhibited impaired stomatal closure under drought. Conversely, HLN1 overexpression stabilized GAD2 mRNA, increased GABA levels, and enhanced drought tolerance in transgenic plants. GAD2 overexpression in hln1 mutants also rescued the drought-sensitive phenotypes. Overall, our study reveals a mechanism whereby HLN1 stabilizes GAD2 mRNA to enhance GABA production and drought tolerance. These findings provide novel strategies for engineering drought-resistant crops.

Trehalose-6-phosphate (T6P), an intermediate in trehalose metabolic pathways, is ubiquitously present in nearly all cellular organisms except vertebrates. The most well-characterized metabolic route involves its synthesis by trehalose-6-phosphate synthase (TPS) and dephosphorylation to trehalose by trehalose-6-phosphate phosphatase (TPP) in the TPS/TPP pathway. Besides, alternative trehalose metabolic pathways aslo exist. In addition to being the precursor of trehalose synthesis, T6P functions as a signal molecule regulating various biological processes. In plants, T6P inhibits SnRK1 (Sucrose-nonfermenting 1 Related Kinase 1), while in fungi, T6P primarily inhibits hexokinase and regulates glycolysis. Notably, TPS and TPP themselves also have some regulatory functions. Genetic studies reveal that deletion of TPS or TPP usually causes developmental and virulence defects in fungi, bacteria and invertebrates. Given that TPS and TPP have important biological functions in pathogenic fungi but are absent in humans and vertebrates, they are ideal targets for fungicide development. This review summarizes trehalose metabolic pathways and the multifaceted roles of T6P in plants, fungi and invertebrates, providing a comprehensive overview of its biological functions. Additionally, it discusses some reported TPS/TPP inhibitor to offer insights for pathogen control strategies.

Wheat stripe rust, caused by an obligate biotrophic pathogen Puccinia striiformis f. sp. tritici (Pst) seriously threatens wheat production. Discovering and utilizing of wheat resistance genes is the most effective and economical method to control diseases. The G-type lectin receptor-like kinase (LecRLKs) involved in biotic stress perception, while their roles in wheat resistance to Pst remain elusive. In our study, we identified 398 G-type LecRKs in wheat through BLAST and HMM profiling. The transcript level of 16 random selected G-type LecRKs from each subfamily were analyzed and found TaSRLK is highly induced by avirulent Pst CYR23 infection. TaSRLK-silenced wheat plants showed reduced resistance to Pst with increased hyphal length and decreased H₂O₂ accumulation. Surprisingly, TaSRLK was localized to the chloroplast and can induce cell death in Nicotiana benthamiana. Further, TaSRLK was shown to interact with and phosphorylate a peroxidase TaPrx1. Importantly, TaPrx1 involved in wheat resistance to Pst through regulating reactive oxygen species (ROS) production. Together these findings demonstrate that TaSRLK positively modulates ROS-associated wheat resistance by binding with TaPrx1.

Plant peptides play crucial roles in various biological processes, including stress responses. This study investigates the functions of plant peptides in response to different adversity stresses, focusing on drought, salt, high temperature, and other environmental challenges. In drought conditions, specific peptides such as CLE25 and CLE9 were found to regulate stomatal closure and root architecture to enhance the efficiency of water utilization. Salt stress induces the expression of CAPE1 and CEP3, which are involved in ion homeostasis and osmoregulation, thereby contributing to salt tolerance in plants. Heat stress triggers the expression of peptides such as CEL45, which contributes to the heat tolerance of cells. Besides, we have also verified a new class of non-conventional peptides, and a large number of non-conventional peptides have been identified in rice seedlings. Understanding the origin and functions of these peptides presents both challenges and opportunities for developing stress-resistant crops. Future research should focus on elucidating the precise molecular mechanisms of peptide-mediated stress responses and exploring their potential applications in agriculture and biotechnology.

The Cucurbitaceae family includes a wide range of economically important fruits and vegetables; however, the laborious and highly inefficient genetic transformation efficacy of cucurbits has hindered the exploration of their gene functions. Virus-induced gene silencing (VIGS) technology, employed from the antiviral RNA silencing defense, has emerged as a viable alternative for high-throughput study of plant gene function. In this study, we successfully established a VIGS system utilizing Trichosanthes mottle mosaic virus (TrMMV), a new member of the genus Tobamovirus. We demonstrated the high efficacy and durability of gene silencing mediated by the TrMMV-VIGS vector in Nicotiana benthamiana, as well as in several cucurbit species, including Cucurbita pepo, Cucumis sativus, C. lanatus, and C. melo. The insertion of 90-400 bp fragments into the vector led to effective silencing of the target gene in both C. sativus and C. melo, with a notably higher silencing efficiency observed in C. melo. Furthermore, the TrMMV-VIGS vector induced a pronounced photobleaching phenotype in the flowers of C. melo, underscoring its potential application in functional genomic research concerning floral traits in this particular species. Taken together, the TrMMV-VIGS system developed herein will facilitate rapid and high-throughput identification of gene functions in cucurbit crops.

Poplar canker, caused by the fungus Cytospora chrysosperma, results in tremendous losses in poplar plantations in China. Although NADPH oxidases (NOXs) play important roles in the development and pathogenicity of several pathogenic fungi, their roles in C. chrysosperma remain unclear. In this study, we characterized three NOX genes (CcNox1, CcNox2, and CcNoxR) in C. chrysosperma. All three genes were highly upregulated during poplar branch infection, and deletion of any of them severely reduced virulence on poplar branches. Furthermore, deletion of either CcNox1 or CcNoxR resulted in a significant increase in endogenous reactive oxygen species production in hyphae, enhanced influx of Ca²⁺, the disruption of redox homeostasis and compromised mitochondrial integrity. Moreover, biosynthesis and secretion of a known virulence factor oxalic acid was obviously defective and exogenous oxalic acid supplementation rescued the virulence of the mutants. Taken together, our findings reveal that NOXs play important roles in redox homeostasis, mitochondrial integrity and pathogenicity in C. chrysosperma.

This review synthesises current research findings and modelling approaches to explore the impact of elevated atmospheric carbon dioxide (eCO₂) concentrations on crop productivity, water and nutrient use efficiency, plant nutritional quality, and the implications for global food security. Over recent decades, rising atmospheric CO₂ levels have sparked significant concern due to their role in driving climate change. While some studies highlight the potential benefits of eCO₂, such as increased crop yields and improved water-use efficiency, many recent investigations reveal a concerning decline in crop nutritional quality. eCO₂ has been shown to reduce concentrations of key nutrients, including nitrogen, minerals, vitamins, polyphenols, and other non-nutrient compounds, as well as alter gene expression. These changes are further complicated by interactions with heat stress and drought, presenting significant challenges in predicting sustainable future crop productivity. These nutritional declines exacerbate the global crisis of malnutrition and hidden hunger, threatening the achievement of Sustainable Development Goal 2 (SDG2), which aims to end hunger and ensure food security. Addressing these challenges requires further research, interdisciplinary collaboration, and innovative approaches to mitigate the adverse effects of eCO₂ on crop physiology and nutritional content while maximising agricultural sustainability. This review aims to provide insights into the complex mechanisms governing crop responses to eCO₂ using wheat as a model and proposes pathways for future research and agricultural practices. These strategies are critical for tackling the intricate dynamics of climate variability, ensuring nutrient-rich food production, and securing food security in the face of a rapidly changing climate.

Zur (zinc uptake regulator), a member of the Fur (ferric uptake regulator) family of transcriptional regulators, plays multifaceted roles by regulating the gene expressions, such as modulating zinc ion uptake by regulating the znuABC gene cluster and influencing bacterial motility by modulating genes associated with flagella or pili. The photosynthetic autotroph Synechocystis sp. PCC 6803 is frequently used as an indicator organism for water pollution and a cell factory for high-value biochemical production in synthetic biology. During its growth, this organism often encounters various abiotic stresses, including oxidative, salt, and antibiotic stress. In this study, we conducted transcriptomic analysis on both Δzur mutant and wild-type (WT) strains to identify potential Zur-regulated genes in Synechocystis sp. PCC 6803. These genes primarily participate in multiple pathways such as inorganic ion transport, carbohydrate transport, energy production and conversion, and cell motility. Zur not only controls zinc ion homeostasis within the cell but also influences the iron balance by directly regulating the expression of the fur gene. In terms of motility, Zur regulates the expression of bacterial pili gene cluster and other motility-related genes, thereby affecting the twitching motility of Synechocystis sp. PCC 6803. Furthermore, Zur plays a crucial role in promoting biofilm formation and enhancing resistance to salt, oxidative, and antibiotic stresses by modulating relative gene expression. In conclusion, as a global transcriptional regulator, Zur plays pivotal roles in metal ion homeostasis, motility, and resistance to multiple stresses in Synechocystis sp. PCC 6803. This study illustrates the Zur regulons in Synechocystis sp. PCC 6803, and underscores the importance of Zur in enhancing the environmental adaptability of cyanobacteria.