College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, China, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
Plant J. 2019 Jun;98(5):783-797. doi: 10.1111/tpj.14271. Epub 2019 Feb 28.
The hypersensitive-induced reaction (HIR) gene family is associated with the hypersensitive response (HR) that is a part of the plant defense system against bacterial and fungal pathogens. The involvement of HIR genes in response to viral pathogens has not yet been studied. We now report that the HIR3 genes of Nicotiana benthamiana and Oryza sativa (rice) were upregulated following rice stripe virus (RSV) infection. Silencing of HIR3s in N. benthamiana resulted in an increased accumulation of RSV RNAs, whereas overexpression of HIR3s in N. benthamiana or rice reduced the expression of RSV RNAs and decreased symptom severity, while also conferring resistance to Turnip mosaic virus, Potato virus X, and the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. Silencing of HIR3 genes in N. benthamiana reduced the content of salicylic acid (SA) and was accompanied by the downregulated expression of genes in the SA pathway. Transient expression of the two HIR3 gene homologs from N. benthamiana or the rice HIR3 gene in N. benthamiana leaves caused cell death and an accumulation of SA, but did not do so in EDS1-silenced plants or in plants expressing NahG. The results indicate that HIR3 contributes to plant basal resistance via an EDS1- and SA-dependent pathway.
超敏诱导反应（HIR）基因家族与植物防御系统对细菌和真菌病原体的超敏反应（HR）有关。HIR 基因在响应病毒病原体中的参与尚未得到研究。我们现在报告说，烟草原生质体和水稻（水稻）的 HIR3 基因在感染水稻条纹病毒（RSV）后上调。在烟草原生质体中沉默 HIR3s 导致 RSV RNAs 的积累增加，而在烟草原生质体或水稻中过表达 HIR3s 则降低 RSV RNAs 的表达并减轻症状严重程度，同时还赋予对芜菁花叶病毒、马铃薯 X 病毒和细菌病原体丁香假单胞菌和稻黄单胞菌的抗性。在烟草原生质体中沉默 HIR3 基因降低了水杨酸（SA）的含量，并伴有 SA 途径中基因的下调表达。瞬时表达来自烟草原生质体的两个 HIR3 基因同源物或水稻 HIR3 基因在烟草原生质体叶片中引起细胞死亡和 SA 的积累，但在 EDS1 沉默的植物或表达 NahG 的植物中则不会。结果表明，HIR3 通过 EDS1 和 SA 依赖途径有助于植物基础抗性。
