A CsWRKY30-centered transcriptional network crucial for immunity activation is elucidates, establishing an important theoretical and molecular foundation for breeding disease-resistant tea cultivars.
Abstract
Tea anthracnose, caused by Colletotrichum camelliae, severely compromises tea yield and quality. However, the molecular mechanisms underlying tea plants resistance to C. camelliae remain poorly understood. In this study, multi-omics profiling revealed that C. camelliae infection triggers a series of resistance responses represented by H2O2 production, carbohydrates reallocation, and especially biosynthesis of defensive phenylpropanoids. Among these, dihydroquercetin, 3-O-methylquercetin, quercetin, and eriodictyol exerted observable antifungal activity. Genetic analysis of genes (CsPAL1 and CsPAL3) encoding phenylpropanoid biosynthesis confirmed the importance of defensive phenylpropanoids in conferring diseases resistance of tea plants to C. camelliae. Meanwhile, the mannitol content increased in tea leaves infected by C. camelliae. Furthermore, overexpression of CsMTD31 encoding mannitol dehydrogenase (MTD) reduced mannitol levels, enhancing ROS accumulation and tea resistance. Notably, we identified that CsWRKY30 directly transactivated CsMTD31, CsPAL1 and CsPAL3 expressions via binding to their promoters. This regulatory action simultaneously increases the content of phenylpropanoids and reduces mannitol levels, thereby enhancing disease resistance in tea plants. Moreover, CsWRKY30 was found to be a hub regulator in activating basal resistance responses, and its overexpression induced a general up-regulation of genes involved in defensive metabolisms and basal immunity. Collectively, this study elucidates a CsWRKY30-centered transcriptional network crucial for immunity activation, establishing an important theoretical and molecular foundation for breeding disease-resistant tea cultivars.
Tea plants frequently encounter combined abiotic and biotic stresses, which severely threaten sustainable tea production. However, how plants integrate responses to multiple stresses remains unclear. Here, we demonstrate that short-term drought preconditioning enhances tea plant susceptibility to infection by the fungal pathogen Pseudopestalotiopsis camelliae-sinensis (Pcs). Transcriptome analysis identified a UDP-dependent glycosyltransferase, CsUGT72BV9, that is co-induced under drought, Pcs infection, and combined stress. Biochemical assays showed that CsUGT72BV9 preferentially glycosylates 4-hydroxycoumarin, a key metabolite in the phenylpropanoid pathway. Silencing CsUGT72BV9 significantly promoted lignin accumulation and enhanced disease resistance, whereas its overexpression reduced resistance, indicating a negative role in defense. Furthermore, CsUGT72BV9 influences jasmonic acid (JA) accumulation, and we identified the transcription factor CsMYC2c, which directly binds to and activates CsUGT72BV9 expression, thereby forming a regulatory module that attenuates disease resistance. Collectively, our findings support a working model in which the CsMYC2c-CsUGT72BV9 module links drought-induced JA signaling to coumarin glycosylation, lignin remodeling and increased susceptibility to Pcs. This study provides new insights into the molecular basis of plant adaptation to complex stress conditions and highlights potential targets for breeding stress-resistant tea varieties.
Theanine, a unique nonproteinogenic natural amino acid predominantly accumulated in tea plants (Camellia sinensis), is a key determinant of tea flavor and quality, with broad applications. Theanine synthase (CsTSI) is a key enzyme in theanine biosynthesis. However, the transcriptional regulation of CsTSI, particularly by bHLH transcription factors, remains largely unexplored. Through coexpression network screening and tissue-specific qPCR, we identified CsbHLH18 as a putative regulator of CsTSI. Yeast one-hybrid (Y1H) and dual-luciferase reporter assays confirmed the direct interaction between CsbHLH18 and the CsTSI promoter. An electrophoretic mobility shift assay (EMSA) further identified the specific binding motif of CsbHLH18 as "CAAATG". Transient overexpression and virus-induced gene silencing (VIGS) in tea plants demonstrated that CsbHLH18 positively regulates theanine biosynthesis by activating CsTSI transcription. These findings elucidate a previously uncharacterized molecular mechanism underlying theanine biosynthesis and provide theoretical insights into molecular breeding and cultivation of high-quality tea varieties.
Yu Fu, Siqing Zhu, Qianlan Liu et al.· Journal of Agricultural and...· 0 citations
Strawberry (Fragaria × ananassa) is highly susceptible to gray mold caused by Botrytis cinerea. WRKY transcription factors and jasmonic acid (JA) are central to defense against necrotrophs, yet the regulatory interaction in strawberry remains unclear. Here, we characterized FaWRKY21, a terpinen-4-ol-responsive, Group IIc WRKY gene encoding a nuclear-localized protein. Transient overexpression in strawberry fruit enhanced defense against B. cinerea and increased endogenous JA concentrations. This enhanced defense was confirmed in transgenic Arabidopsis plants overexpressing FaWRKY21, where AtPDF1.2 and other defense markers were upregulated. Transcriptomic and qRT-PCR analyses revealed that FaWRKY21 upregulates JA biosynthetic genes, notably FaOPR3II, FaJMT, and FaAOS-C. Yeast one-hybrid, EMSA, and dual-luciferase assays demonstrated direct binding to W-box elements in their promoters and transcriptional activation. Our findings establish FaWRKY21 as a direct activator of JA biosynthesis that positively regulates defense against B. cinerea, offering molecular targets for developing elicitor-based strategies to control postharvest gray mold.
Meng-Ze Wei, Yi Chen, Yijia You et al.· Journal of Agricultural and...· 0 citations
Tea gray blight, caused by the Pestalotiopsis-like species, poses a major threat to global tea production. The pathogen’s complexity, characterized by cryptic diversity (Pestalotiopsis, Pseudopestalotiopsis, and Neopestalotiopsis) and a dynamic ‘endophyte-pathogen’ lifestyle switch modulated by ecological factors, complicates effective control. Synthesizing recent breakthroughs in multi-omics and functional genomics, this review delineates a tripartite defense architecture in tea plants: (1) Signal-Epigenetic Coordination, featuring a unique spatiotemporal synergy between Salicylic Acid (SA) and Jasmonic Acid (JA), and a CsPRMT5-mediated histone methylation module that functions as a ‘molecular brake’ to fine-tune immune onset; (2) Metabolic Flux Redirection, wherein alternative splicing (e.g., CsDFR isoforms) acts as a rapid switch to prioritize the biosynthesis of high-potency esterified catechins and volatiles; and (3) Physical Reinforcement, driven by miRNA-regulated lignification (e.g., the miR397a-CsLAC17 module). To bridge the critical ‘translation gap’ between mechanistic discovery and field stability, we propose a closed-loop research framework. This roadmap integrates pan-genome taxonomy to resolve classification ambiguities, RNP-CRISPR gene editing to validate effector-receptor interactions, synthetic microbial communities for ecological engineering, and AI-driven precision management. This review not only decodes the molecular dialogue in the tea-Pestalotiopsis pathosystem but also provides a blueprint for leveraging systems biology to achieve resilient, quality-preserving disease control.
Qingtao Jiang, Chengcheng Yang, Xujie Wang et al.· Horticulture Research· 0 citations
In recent years, tea leaf spot, caused by the fungus Epicoccum sorghinum, adversely affects both the yield and quality of tea in China. Transient overexpression and antisense oligonucleotide (AsODN) assays revealed that upregulating CsMYB1, a transcription factor located in the nucleus, enhances resistance to E. sorghinum infection in tea leaves. Overexpression of CsMYB1 in transgenic Nicotiana benthamiana conferred resistance to Botrytis cinerea. Multi-omics assays of transiently overexpressed CsMYB1 in tea leaves indicated that CsMYB1 induces the expression of numerous disease resistance genes. DNA affinity purification sequencing assay indicated that CsMYB1 can activate the expression of the disease resistance gene pectinesterase/pectinesterase inhibitor 41 (CsPME41). β-glucuronidase and dual-luciferase assays showed that csi-miR858-3p_L-1 targets and cleaves CsMYB1. Moreover, transient overexpression and AsODN assays in tea leaves and transgenic csi-miR858-3p_L-1 N. benthamiana plants indicated that increasing csi-miR858-3p_L-1 levels heightens susceptibility to E. sorghinum in tea leaves. The relative expression levels of CsMYB1, CsPME41, and csi-miR858-3p_L-1 in tea leaves exhibited distinct spatial and temporal patterns in response to E. sorghinum invasion. This study reveals that the csi-miR858-3p_L-1–CsMYB1–CsPME41 module plays a role in the disease resistance response of tea plants to E. sorghinum infection, providing crucial data for resistance breeding.
Dongqin Zhang, Bin Wang, Zeqi Qi et al.· Molecular Horticulture· 0 citations
Colletotrichum viniferum, the causal agent of grape ripe rot and leaf spot, poses a serious threat to grape yield and fruit quality. Like many phytopathogens, C. viniferum secretes effector proteins; however, the molecular mechanisms by which these effectors manipulate host immune responses remain poorly understood. In this study, we functionally characterized a candidate effector, CvA10999. CvA10999 suppressed INF1 (infestans 1, P. infestans PAMP elicitor) triggered cell death in Nicotiana benthamiana and was significantly upregulated during C. viniferum infection of susceptible grape V. vinifera cv. Thompson Seedless (TS) leaves. Targeted deletion of CvA10999 resulted in reduced sporulation, abnormal appressorium formation, and attenuated virulence on TS leaves. Further analysis revealed that CvA10999 interacts with the grape protein β-subunit of sucrose non-fermenting 1-related protein kinase (VvSnRKb1). Transient overexpression of VvSnRKb1 in TS leaves, as well as stable transgenic grapevines overexpressing VvSnRKb1, conferred enhanced resistance to C. viniferum. Mechanistically, CvA10999 bound to VvSnRKb1, disrupting its interaction with nonexpressor of pathogenesis-related genes 1 (VvNPR1) and interfering with VvNPR1 phosphorylation. This likely impaired the transcriptional activator function of VvNPR1 and downregulated salicylic acid (SA)-responsive pathogenesis-related (PR) genes. Collectively, these findings demonstrate that CvA10999 targets VvSnRKb1 to subvert host immunity and promote C. viniferum infection.
