PDF(Pubmed)
Abstract：
Variations in chromosome number are occasionally observed among oomycetes, a group that includes many plant pathogens, but the emergence of such variations and their effects on genome and virulence evolution remain ambiguous. We generated complete telomere-to-telomere genome assemblies for Phytophthora sojae, Globisporangium ultimum, Pythium oligandrum, and G. spinosum. Reconstructing the karyotype of the most recent common ancestor in Peronosporales revealed that frequent chromosome fusion and fission drove changes in chromosome number. Centromeres enriched with Copia-like transposons may contribute to chromosome fusion and fission events. Chromosome fusion facilitated the emergence of pathogenicity genes and their adaptive evolution. Effectors tended to duplicate in the sub-telomere regions of fused chromosomes, which exhibited evolutionary features distinct to the non-fused chromosomes. By integrating ancestral genomic dynamics and structural predictions, we have identified secreted Ankyrin repeat-containing proteins (ANKs) as a novel class of effectors in P. sojae. Phylogenetic analysis and experiments further revealed that ANK is a specifically expanded effector family in oomycetes. These results revealed chromosome dynamics in oomycete plant pathogens, and provided novel insights into karyotype and effector evolution.
摘要：
在卵菌中偶尔观察到染色体数量的变化，一个包括许多植物病原体的群体，但是这种变异的出现及其对基因组和毒力进化的影响仍然模棱两可。我们为大豆疫霉生成了完整的端粒到端粒基因组组装，gloisporangiumultimum,寡雄腐霉，还有G.spinosum.重建Peronosporales最新共同祖先的核型表明，频繁的染色体融合和裂变驱动染色体数量的变化。富含Copia样转座子的着丝粒可能有助于染色体融合和裂变事件。染色体融合促进了致病基因的出现及其适应性进化。效应物倾向于在融合染色体的端粒亚区域复制，表现出与非融合染色体不同的进化特征。通过整合祖先的基因组动力学和结构预测，我们已经确定分泌的含有Ankyrin重复序列的蛋白质（ANK）是大豆假单胞菌中的一类新型效应物。系统发育分析和实验进一步表明，ANK是卵菌中一个特别扩展的效应子家族。这些结果揭示了卵菌植物病原体的染色体动力学，并为核型和效应子进化提供了新的见解。
