Peltaster fructicola genome reveals evolution from an invasive phytopathogen to an ectophytic parasite.
Peltaster fructicola genome reveals evolution from an invasive phytopathogen to an ectophytic parasite.
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Peltaster fructicola 基因组揭示了从入侵植物病原体到外生寄生虫的进化
DOI：
10.1038/srep22926
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发表时间：
2016-03-11
影响因子：
4.6
通讯作者：
Sun G
中科院分区：
文献类型：
--
作者：
Xu C;Chen H;Gleason ML;Xu JR;Liu H;Zhang R;Sun G
烟斑和蝇斑（SBFS）真菌是非常规的植物病原体，通过玷污受感染的水果的表面外观而造成经济损失。在这里，我们介绍了18.14 Mb的基因组Peltaster fructicola，苹果上最流行的SBFS物种之一。这个小型组装体仅包含8，334个预测的蛋白质编码基因和非常小的重复元件库。系统发育基因组学和比较基因组学研究表明，果生假单胞菌经历了一个还原性进化过程，在此过程中，孤儿基因、细胞壁降解基因、次生代谢基因、分泌的肽酶基因和效应子基因的数量急剧减少。相反，控制1，8-二羟基萘（DHN）-黑色素生物合成和附着胞介导的渗透的基因基本上保留。此外，对受感染苹果表面的显微镜检查首次表明，苹果疫霉不仅能溶解表皮蜡，而且能部分穿透表皮。我们的研究结果表明，基因组收缩，其主要特征是大量的致病性相关基因的丢失，已发挥了重要作用，在P. fructicola（并暗示其他SBFS物种）从植物穿透的祖先到非入侵的外生植物，显示了一种新的形式的植物和真菌之间的营养相互作用。
Sooty blotch and flyspeck (SBFS) fungi are unconventional plant pathogens that cause economic losses by blemishing the surface appearance of infected fruit. Here, we introduce the 18.14-Mb genome of Peltaster fructicola, one of the most prevalent SBFS species on apple. This undersized assembly contains only 8,334 predicted protein-coding genes and a very small repertoire of repetitive elements. Phylogenomics and comparative genomics revealed that P. fructicola had undergone a reductive evolution, during which the numbers of orphan genes and genes involved in plant cell wall degradation, secondary metabolism, and secreted peptidases and effectors were drastically reduced. In contrast, the genes controlling 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis and appressorium-mediated penetration were retained substantially. Additionally, microscopic examination of the surfaces of infected apple indicated for the first time that P. fructicola can not only dissolve epicuticular waxes but also partially penetrate the cuticle proper. Our findings indicate that genome contraction, characterized mainly by the massive loss of pathogenicity-related genes, has played an important role in the evolution of P. fructicola (and by implication other SBFS species) from a plant-penetrating ancestor to a non-invasive ectophyte, displaying a novel form of trophic interaction between plants and fungi.