Infection mechanisms and putative effector repertoire of the mosquito pathogenic oomycete Pythium guiyangense uncovered by genomic analysis
Infection mechanisms and putative effector repertoire of the mosquito pathogenic oomycete Pythium guiyangense uncovered by genomic analysis
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通过基因组分析揭示蚊子致病卵菌贵阳腐霉的感染机制和假定效应子库
DOI：
10.1371/journal.pgen.1008116
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发表时间：
2019-04-01
期刊：
影响因子：
4.5
通讯作者：
Xia, Ai
中科院分区：
文献类型：
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作者：
Shen, Danyu;Tang, Zhaoyang;Xia, Ai
贵阳腐霉是一种主要来自植物病原体属的卵菌，是一种有效的生防剂，在控制各种蚊子方面具有广泛的潜力。然而，它的灭蚊机制几乎不为人知。在本研究中，我们观察到贵阳拟青霉可以利用角质层穿透和摄取菌丝进入消化系统来感染蚊子幼虫。为了探讨致病机理，我们获得了239个重叠群和1009kb的N50重叠群序列。基因组组装约为110Mb，几乎是其他已测序腐霉基因组的两倍。进一步的基因组分析表明，贵阳白杨可能来自两个相关但不同的亲本物种的杂交。系统发育分析表明，贵阳疫霉可能是由与植物病原菌相同的共同祖先进化而来。比较基因组分析结合转录组测序数据表明，贵阳拟青霉可能通过多种毒力机制感染蚊虫，包括分泌型蛋白水解酶和Kazal型蛋白水解酶抑制剂。它还与植物病原卵菌共同使用细胞内CRN(CRN)效应器，以促进植物寄主的定植。我们的实验证据表明，贵阳拟青霉的CRN效应物对昆虫细胞具有毒性。本研究发现的贵阳按蚊的感染机制和可能的毒力效应因子，为制定改进的灭蚊策略提供了依据。这些数据还提供了有关卵菌谱系中昆虫病原生活方式的宿主适应和进化的有用知识。更深入地了解贵阳松毛虫的生物学特性，也可能对其他重要农业害虫的管理有所帮助。
Pythium guiyangense, an oomycete from a genus of mostly plant pathogens, is an effective biological control agent that has wide potential to manage diverse mosquitoes. However, its mosquito-killing mechanisms are almost unknown. In this study, we observed that P. guiyangense could utilize cuticle penetration and ingestion of mycelia into the digestive system to infect mosquito larvae. To explore pathogenic mechanisms, a high-quality genome sequence with 239 contigs and an N50 contig length of 1,009 kb was generated. The genome assembly is approximately 110 Mb, which is almost twice the size of other sequenced Pythium genomes. Further genome analysis suggests that P. guiyangense may arise from a hybridization of two related but distinct parental species. Phylogenetic analysis demonstrated that P. guiyangense likely evolved from common ancestors shared with plant pathogens. Comparative genome analysis coupled with transcriptome sequencing data suggested that P. guiyangense may employ multiple virulence mechanisms to infect mosquitoes, including secreted proteases and kazal-type protease inhibitors. It also shares intracellular Crinkler (CRN) effectors used by plant pathogenic oomycetes to facilitate the colonization of plant hosts. Our experimental evidence demonstrates that CRN effectors of P. guiyangense can be toxic to insect cells. The infection mechanisms and putative virulence effectors of P. guiyangense uncovered by this study provide the basis to develop improved mosquito control strategies. These data also provide useful knowledge on host adaptation and evolution of the entomopathogenic lifestyle within the oomycete lineage. A deeper understanding of the biology of P. guiyangense effectors might also be useful for management of other important agricultural pests.