Noon Jason B, Qi Mingsheng, Sill Danielle N, Muppirala Usha, Eves-van den Akker Sebastian, Maier Thomas R, Dobbs Drena, Mitchum Melissa G, Hewezi Tarek, Baum Thomas J
Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA.
Genome Informatics Facility, Iowa State University, Ames, IA, 50011, USA.
New Phytol. 2016 Oct;212(2):444-60. doi: 10.1111/nph.14047. Epub 2016 Jun 6.
Heterodera glycines, the soybean cyst nematode, delivers effector proteins into soybean roots to initiate and maintain an obligate parasitic relationship. HgGLAND18 encodes a candidate H. glycines effector and is expressed throughout the infection process. We used a combination of molecular, genetic, bioinformatic and phylogenetic analyses to determine the role of HgGLAND18 during H. glycines infection. HgGLAND18 is necessary for pathogenicity in compatible interactions with soybean. The encoded effector strongly suppresses both basal and hypersensitive cell death innate immune responses, and immunosuppression requires the presence and coordination between multiple protein domains. The N-terminal domain in HgGLAND18 contains unique sequence similarity to domains of an immunosuppressive effector of Plasmodium spp., the malaria parasites. The Plasmodium effector domains functionally complement the loss of the N-terminal domain from HgGLAND18. In-depth sequence searches and phylogenetic analyses demonstrate convergent evolution between effectors from divergent parasites of plants and animals as the cause of sequence and functional similarity.
大豆胞囊线虫（Heterodera glycines）会向大豆根中输送效应蛋白，以建立并维持专性寄生关系。HgGLAND18编码一种大豆胞囊线虫效应蛋白候选物，且在整个感染过程中均有表达。我们综合运用分子、遗传、生物信息学和系统发育分析方法，以确定HgGLAND18在大豆胞囊线虫感染过程中的作用。在与大豆的亲和性互作中，HgGLAND18对致病性而言是必需的。所编码的效应蛋白能强烈抑制基础细胞死亡和超敏细胞死亡这两种先天免疫反应，且免疫抑制需要多个蛋白结构域的存在与协同作用。HgGLAND18的N端结构域与疟原虫（Plasmodium spp.）的一种免疫抑制效应蛋白的结构域具有独特的序列相似性。疟原虫效应蛋白结构域在功能上可弥补HgGLAND18 N端结构域的缺失。深入的序列搜索和系统发育分析表明，动植物不同寄生虫的效应蛋白之间存在趋同进化，这是序列和功能相似性的原因。
