Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA.
Indigo Agriculture, Charlestown, Massachusetts, 02129, USA.
Sci Rep. 2017 Jul 17;7(1):5643. doi: 10.1038/s41598-017-06068-4.
Epichloë spp. are naturally occurring fungal endophytic symbionts of many cool-season grasses. Infection by the fungal endophytes often confers biotic and abiotic stress tolerance to their hosts. Endophyte-mediated disease resistance is well-established in the fine fescue grass Festuca rubra subsp. rubra (strong creeping red fescue) infected with E. festucae. Resistance to fungal pathogens is not an established effect of endophyte infection of other grass species, and may therefore be unique to the fine fescues. The underlying mechanism of the disease resistance is unknown. E. festucae produces a secreted antifungal protein that is highly expressed in the infected plant tissues and may therefore be involved in the disease resistance. Most Epichloë spp. do not have a gene for a similar antifungal protein. Here we report the characterization of the E. festucae antifungal protein, designated Efe-AfpA. The antifungal protein partially purified from the apoplastic proteins of endophyte-infected plant tissue and the recombinant protein expressed in the yeast Pichia pastoris was found to have activity against the important plant pathogen Sclerotinia homoeocarpa. Efe-AfpA may therefore be a component of the disease resistance seen in endophyte-infected strong creeping red fescue.
内生真菌 Epichloë spp. 是许多冷季型禾草的天然真菌内生共生体。真菌内生体的感染通常赋予宿主生物和非生物胁迫耐受性。内生体介导的抗病性在细羊茅 Festuca rubra subsp. rubra(强匍匐红羊茅)感染 E. festucae 中得到了很好的证实。对真菌病原体的抗性不是其他禾本科植物内生体感染的既定效应,因此可能是细羊茅特有的。抗病性的潜在机制尚不清楚。E. festucae 产生一种分泌的抗真菌蛋白,在感染的植物组织中高度表达,因此可能参与了抗病性。大多数 Epichloë spp. 没有类似抗真菌蛋白的基因。在这里,我们报告了 E. festucae 抗真菌蛋白的特性,命名为 Efe-AfpA。从内生体感染植物组织的质外体蛋白中部分纯化的抗真菌蛋白和在酵母 Pichia pastoris 中表达的重组蛋白被发现对重要的植物病原体核盘菌具有活性。因此,Efe-AfpA 可能是内生体感染强匍匐红羊茅中观察到的抗病性的一个组成部分。