首页|期刊导航|农业科学学报（英文）|Citrus PR4A is involved in the defense responses against Xanthomonas citri subsp.citri.
农业科学学报（英文）2025，Vol.24Issue(12)：4643-4655,13.DOI:10.1016/j.jia.2024.11.011
Citrus PR4A is involved in the defense responses against Xanthomonas citri subsp.citri.
Citrus PR4A is involved in the defense responses against Xanthomonas citri subsp.citri
摘要
Abstract
Citrus canker,caused by Xanthomonas citri subsp.citri(Xcc),is a globally quarantine disease infecting nearly all Citrus cultivars.Citron C-05 has been identified with complete and active resistance to Xcc.However,the mechanism underlying Citron C-05's resistance to Xcc remains elusive.We identified a gene cluster on chromosome 8 of the citrus genome comprising five pathogenesis-related 4-like genes.PR4A was upregulated in Citron C-05 leaves under Xcc infection,exhibiting the highest expression among these PR4-like genes.In addition,PR4A expression was higher in leaves of disease-resistant genotypes than susceptible genotypes under Xcc invasion.Bimolecular fluorescence complementation(BiFC)and Split-Luc assays indicated that CmWRKY75,a positive regulator of PR4A,interacted with pthA4 and upregulated expression of PR4A in Citron C-05 leaves.Regulatory function for the expression of CmPR4A was localized to a 516-nucleotide region upstream of the translational start site,which was designated ProCmPR4A-P516.Transient overexpression of CmPR4A improved resistance to Xcc in sweet orange,and three transgenic lines of OE-CmPR4A exhibited resistance to Pseudomonas syringae pv.tomato DC3000(Pst DC3000)in Arabidopsis.Furthermore,CmSMU2 was identified through yeast two-hybrid library using CmPR4A as bait,BiFC and Split-Luc assays further verified their interaction.Transient overexpression of CmSMU2 in sweet orange increased resistance to Xcc.Co-expression of CmSMU2 and CmPR4A enhanced accumulation of reactive oxygen species compared to CmSMU2 or CmPR4A,indicating that they may synergistically enhance resistance to Xcc in citrus.These findings lay the groundwork for a theoretical analysis of the mechanism underlying the resistance of Citron C-05 against citrus canker.关键词
Citron C-05/citrus canker/pathogenesis-related protein/PR4A/SMU2/reactive oxygen speciesKey words
Citron C-05/citrus canker/pathogenesis-related protein/PR4A/SMU2/reactive oxygen species引用本文复制引用
Chenxing Hao,Jian Han,Peihan Yan,Jia Ouyang,Ling Sheng,Guiyou Long,Ziniu Deng,Yunlin Cao,Xianfeng Ma..Citrus PR4A is involved in the defense responses against Xanthomonas citri subsp.citri.[J].农业科学学报（英文）,2025,24(12):4643-4655,13.基金项目
This work was supported by the National Natural Science Foundation of China(32402500 and 31741110)and the Scientific Research Fund of Hunan Provincial Education Department,China(21B0220). （32402500 and 31741110）
