Scientists reveal gene that weakens tea disease resistance
image: A model of CsPRMT5 regulation of CsMAPK3 expression represses resistance to gray blight in tea plant. CsPRMT5 binds to defense-related genes, including CsMAPK3, and regulates their expression through H4R3sme2 modification. Under normal growth conditions, CsPRMT5 associates with CsMAPK3 to mediate its H4R3sme2, inhibiting the expression of CsMAPK3. After infection by the gray blight pathogen (Ps), the expression of CsPRMT5 is suppressed, leading to less CsPRMT5 association with chromatin and a decline in H4R3sme2 levels, thereby releasing the transcriptional suppression of pathogen-induced CsMAPK3 and enhancing plant resistance.. Image link: https://academic.oup.com/view-large/figure/521467791/uhaf100f7.tif?login=false
Credit: Horticulture Research
Tea is one of the world’s most economically valuable crops, but fungal gray blight causes severe leaf damage and yield loss. Previous research has shown that immune responses in tea involve phenylpropanoid metabolism, WRKY transcription factors, salicylic acid signaling, and multi-omics defense reprogramming. However, how histone arginine methylation shapes disease resistance remained unknown. Protein arginine methyltransferases (PRMTs) regulate key chromatin states affecting transcription activation or inhibition in plants. Among them, Type II PRMT5 is known to deposit H4R3sme2 and often acts as a transcriptional repressor. Due to these unanswered questions, deeper investigation into PRMT-mediated epigenetic defense control mechanisms is urgently needed.
Researchers from Anhui Agricultural University reported (DOI: 10.1093/hr/uhaf100) on April 9, 2025, in Horticulture Research that the gene CsPRMT5 functions as a negative regulator of gray blight resistance in tea plants. Through gene silencing, overexpression, histone methylation profiling, RNA-seq, and ChIP-seq, the team found that PRMT5-mediated H4R3 dimethylation represses disease-responsive pathways. Suppressing CsPRMT5 reduced lesion development, boosted ROS-detoxifying enzyme activity, and strongly induced the defense kinase CsMAPK3, demonstrating an epigenetic switch controlling immune activation.
The researchers first monitored histone arginine methylation dynamics after fungal infection. They observed that H4R3sme2 levels dropped continuously after inoculation, coinciding with the downregulation of CsPRMT5. Seven tea cultivars were compared, and a strong positive correlation was identified between CsPRMT5 expression and lesion severity—cultivars with naturally lower CsPRMT5 were more resistant. Using antisense oligonucleotide-based gene silencing, tea leaves displayed smaller lesion areas and higher expression of immune genes such as CsPR1, CsPP2C, and CsDSP1. Overexpression of CsPRMT5 had the opposite effect, increasing susceptibility.
RNA-seq revealed 748 genes upregulated upon CsPRMT5 suppression, with immune pathways significantly enriched. ChIP-seq further confirmed that PRMT5 binds to defense genes, and ChIP-qPCR validated direct association with the CsMAPK3 promoter. Under infection, CsPRMT5 dissociation reduced H4R3sme2 deposition, lifting transcriptional repression and leading to enhanced CsMAPK3 activity. Overexpression of CsMAPK3 improved resistance, while silencing reversed the protective effect. The mechanism was also conserved across species—heterologous expression in Arabidopsis restored susceptibility in prmt5 mutants.
Lead authors stated that this work reveals an essential epigenetic checkpoint controlling tea immunity. “Our study demonstrates that CsPRMT5 operates as a molecular brake,” the researchers noted. “By reducing CsPRMT5 levels, tea plants can rapidly activate defense genes and strengthen protection against gray blight. Targeting histone arginine methylation opens exciting opportunities to enhance disease resistance without compromising growth.” They further emphasized that PRMT-mediated chromatin modifications could become a powerful tool for precision breeding of stress-resilient tea varieties.
This discovery offers promising molecular targets for developing disease-resistant tea cultivars through selective breeding, genome editing, or epigenetic modulation of CsPRMT5. By suppressing repressive histone marks, plants could activate defense pathways more efficiently under pathogen challenge, reducing chemical control needs and improving sustainable tea production. As PRMT5 functions are conserved among crops, similar strategies may enhance resistance in economically important species like rice, potato, and maize. Future work could integrate PRMT regulation with chromatin acetylation, DNA methylation, and metabolite-based immunity to build multi-layered protection networks for future agriculture.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhaf100
Funding information
This research was supported by the National Natural Science Foundation of China (32072624, 32402622, 32402623), the National Key R&D Program of China (2021YFD1601101), the Postdoctoral Fellowship Program of CPSF under Grant Number GZC20240006 and China Postdoctoral Science Foundation (2024 M750020), the Open Fund of State Key Laboratory of Tea Plant Biology and Utilization, SKLTOF20220115.
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.