The Sainsbury Laboratory, John Innes Centre, Norwich Research Park, Norwich, UK.
Plant Signal Behav. 2012 Jan;7(1):145-9. doi: 10.4161/psb.7.1.18450.
We examined changes to subcellular architecture during the compatible interaction between the biotroph pathogen Hyaloperonospora arabidopsidis (Hpa) and its host Arabidopsis. Live-cell imaging highlighted rearrangements in plant cell membranes upon infection. In particular, the tonoplast appeared close to the extrahaustorial membrane surrounding the haustorium. We investigated the subcellular localization patterns of Hpa RxLR effector candidates (HaRxLs) in planta. This subcellular localization screening led to the identification of an extrahaustorial membrane-localized effector, HaRxL17 that when stably expressed in Arabidopsis increased plant susceptibility to Hpa during compatible and incompatible interactions. Here, we report that the N-terminal part of HaRxL17 is sufficient to target the plant cell membranes. We showed that both C- or N-terminal fluorescent-tagged HaRxL17 localizes around Hpa haustoria, in early and in late stages of infection. As with Hpa infection, GFP-HaRxL17 also localizes around haustoria during infection with Albugo laibachii. Thus, HaRxL17 that increases plant susceptibility to Hpa during both compatible and incompatible interactions, localizes around oomycete haustoria when stably expressed in Arabidopsis.
我们研究了生物亲和性病原菌 Hyaloperonospora arabidopsidis（Hpa）与其宿主拟南芥之间兼容互作过程中细胞亚结构的变化。活细胞成像突出显示了感染过程中植物细胞膜的重排。特别是液泡膜似乎靠近围绕吸器的外生膜。我们研究了 Hpa RxLR 效应子候选物（HaRxLs）在植物体内的亚细胞定位模式。这种亚细胞定位筛选导致鉴定出一种定位于外生膜的效应子 HaRxL17，当在拟南芥中稳定表达时，它会增加植物对 Hpa 的易感性，无论是在兼容还是不兼容的互作中。在这里，我们报告 HaRxL17 的 N 端部分足以靶向植物细胞膜。我们表明，无论是 C 端还是 N 端荧光标记的 HaRxL17，在感染的早期和晚期，都定位于 Hpa 吸器周围。与 Hpa 感染一样，GFP-HaRxL17 在感染 Albugo laibachii 时也定位于吸器周围。因此，当在拟南芥中稳定表达时，HaRxL17 会增加植物对 Hpa 的易感性，无论是在兼容还是不兼容的互作中，都定位于卵菌吸器周围。
