Kingdom-Wide Analysis of Fungal Small Secreted Proteins (SSPs) Reveals their Potential Role in Host Association
Kingdom-Wide Analysis of Fungal Small Secreted Proteins (SSPs) Reveals their Potential Role in Host Association
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DOI：
10.3389/fpfs.2016.00186
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发表时间：
2016-02-19
影响因子：
5.6
通讯作者：
Lee, Yong-Hwan
中科院分区：
文献类型：
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作者：
Kim, Ki-Tae;Jeon, Jongbum;Lee, Yong-Hwan
真菌分泌组由多种蛋白质功能基团组成，其中许多蛋白质参与营养获取、自我保护或对环境和邻近生物的操纵。分泌体中特征最少的成分是小分泌蛋白(SSPs)。据报道，一些SSP具有效应器的功能，但大多数仍有待研究。主要分泌体成分的组成，如碳水化合物活性酶、蛋白水解酶、脂肪酶和氧化还原酶，似乎反映了个体物种的生活方式和生态位。我们假设许多SSP作为效应器参与操纵植物。与通常使用细胞壁降解酶和植物毒素杀死宿主的坏死营养因子相比，专性生物营养因子可能编码更多和不同的效应器样SSP来抑制宿主防御。由于不同的研究使用了不同的分泌组预测工作流程，现有的分泌组数据很难整合，以便进行全面的比较研究来检验这一假说。在这项研究中，通过改进的分泌组工作流程，从真菌分泌组数据库(FSD)中的数据中鉴定了由136个真菌物种编码的SSP。随后，根据分类群和生活方式对SSP和其他分泌组分的组成进行了比较。那些与寄主细胞关系密切的物种，如生物营养体和共生体，通常比半生物营养体和坏死营养体具有更高比例的物种特异性SSP(SSSP)，但后者显示出更高比例的分泌酶。我们的研究结果为SSP的功能研究奠定了基础，也将有助于理解潜在支持不同真菌生活方式的基因组变化。
Fungal secretome consists of various functional groups of proteins, many of which participate in nutrient acquisition, self-protection, or manipulation of the environment and neighboring organisms. The least characterized component of the secretome is small secreted proteins (SSPs). Some SSPs have been reported to function as effectors, but most remain to be characterized. The composition of major secretome components, such as carbohydrate active enzymes, proteases, lipases, and oxidoreductases, appear to reflect the lifestyle and ecological niche of individual species. We hypothesize that many SSPs participate in manipulating plants as effectors. Obligate biotrophs likely encode more and diverse effector-like SSPs to suppress host defense compared to necrotrophs, which generally use cell wall degrading enzymes and phytotoxins to kill hosts. Because different secretome prediction workflows have been used in different studies, available secretome data are difficult to integrate for comprehensive comparative studies to test this hypothesis. In this study, SSPs encoded by 136 fungal species were identified from data archived in Fungal Secretome Database (FSD) via a refined secretome workflow. Subsequently, compositions of SSPs and other secretome components were compared in light of taxa and lifestyles. Those species that are intimately associated with host cells, such as biotrophs and symbionts, usually have higher proportion of species-specific SSPs (SSSPs) than hemibiotrophs and necrotrophs, but the latter groups displayed higher proportions of secreted enzymes. Results from our study established a foundation for functional studies on SSPs and will also help understand genomic changes potentially underpinning different fungal lifestyles.