North Carolina State University, Department of Plant Pathology, Raleigh, NC 27607, USA.
Mol Plant Pathol. 2011 May;12(4):355-64. doi: 10.1111/j.1364-3703.2010.00675.x. Epub 2010 Nov 18.
The expression pattern of pathogenesis-related genes PR-1 to PR-5 was examined in the roots and leaves of Arabidopsis thaliana plants on infection with beet-cyst (Heterodera schachtii) and root-knot (Meloidogyne incognita) nematodes. During H. schachtii parasitism of Arabidopsis, the expression of PR-1, PR-2 and PR-5, which are considered to be markers for salicylic acid (SA)-dependent systemic acquired resistance (SAR), was induced in both roots and leaves of infected plants. In addition, the expression of PR-3 and PR-4, which are used as markers for jasmonic acid (JA)-dependent SAR, was not altered in roots, but in the leaves of H. schachtii-infected plants, the expression PR-3 was induced, whereas the expression of PR-4 was down-regulated. During M. incognita infection of Arabidopsis, the expression of PR-1, PR-2 and PR-5 was highly induced in roots, as was PR-3 to a lesser extent, but the expression of PR-4 was not altered, indicating that infection with M. incognita activated both SA- and JA-dependent SAR in roots. However, all PRgenes examined (PR-1 to PR-5) were down-regulated in the leaves of M. incognita-infected plants, suggesting the suppression of both SA- and JA-dependent SAR. Furthermore, constitutive expression of a single PR in Arabidopsis altered the transcription patterns of other PR genes, and the over-expression of PR-1 reduced successful infection by both H. schachtii and M. incognita, whereas the over-expression of PR-3 reduced host susceptibility to M. incognita but had no effect on H. schachtii parasitism. The results suggest that fundamental differences in the mechanisms of infection by beet-cyst and root-knot nematodes differentially regulate PR protein production and mobilization within susceptible host plants.
在感染甜菜胞囊线虫(Heterodera schachtii)和根结线虫(Meloidogyne incognita)后,拟南芥(Arabidopsis thaliana)植物的根和叶中与发病相关基因 PR-1 至 PR-5 的表达模式被检测到。在拟南芥被 H. schachtii 寄生期间,被认为是水杨酸(SA)依赖性系统获得性抗性(SAR)标记的 PR-1、PR-2 和 PR-5 在受感染植物的根和叶中均被诱导。此外,被用作茉莉酸(JA)依赖性 SAR 标记的 PR-3 和 PR-4 在根中未改变,但在 H. schachtii 感染的植物叶片中,PR-3 的表达被诱导,而 PR-4 的表达被下调。在拟南芥感染 M. incognita 期间,PR-1、PR-2 和 PR-5 在根中高度诱导,PR-3 也有一定程度的诱导,但 PR-4 未改变,表明 M. incognita 感染激活了根中 SA 和 JA 依赖性 SAR。然而,在 M. incognita 感染的植物叶片中,所有检测到的 PR 基因(PR-1 至 PR-5)均被下调,表明 SA 和 JA 依赖性 SAR 均被抑制。此外,拟南芥中单个 PR 的组成型表达改变了其他 PR 基因的转录模式,PR-1 的过表达降低了 H. schachtii 和 M. incognita 的成功感染,而 PR-3 的过表达降低了宿主对 M. incognita 的易感性,但对 H. schachtii 的寄生没有影响。结果表明,甜菜胞囊线虫和根结线虫感染机制的根本差异调节了易感宿主植物中 PR 蛋白的产生和动员。