Lassiter Erica S, Russ Carsten, Nusbaum Chad, Zeng Qiandong, Saville Amanda C, Olarte Rodrigo A, Carbone Ignazio, Hu Chia-Hui, Seguin-Orlando Andaine, Samaniego Jose A, Thorne Jeffrey L, Ristaino Jean B
Department of Biological Sciences, North Carolina State University, Raleigh, NC, 27695, USA.
BROAD Institute, MIT, Cambridge, MA, 02142, USA.
Curr Genet. 2015 Nov;61(4):567-77. doi: 10.1007/s00294-015-0480-3. Epub 2015 Mar 10.
Phytophthora infestans is one of the most destructive plant pathogens of potato and tomato globally. The pathogen is closely related to four other Phytophthora species in the 1c clade including P. phaseoli, P. ipomoeae, P. mirabilis and P. andina that are important pathogens of other wild and domesticated hosts. P. andina is an interspecific hybrid between P. infestans and an unknown Phytophthora species. We have sequenced mitochondrial genomes of the sister species of P. infestans and examined the evolutionary relationships within the clade. Phylogenetic analysis indicates that the P. phaseoli mitochondrial lineage is basal within the clade. P. mirabilis and P. ipomoeae are sister lineages and share a common ancestor with the Ic mitochondrial lineage of P. andina. These lineages in turn are sister to the P. infestans and P. andina Ia mitochondrial lineages. The P. andina Ic lineage diverged much earlier than the P. andina Ia mitochondrial lineage and P. infestans. The presence of two mitochondrial lineages in P. andina supports the hybrid nature of this species. The ancestral state of the P. andina Ic lineage in the tree and its occurrence only in the Andean regions of Ecuador, Colombia and Peru suggests that the origin of this species hybrid in nature may occur there.
致病疫霉是全球马铃薯和番茄最具毁灭性的植物病原体之一。该病原体与1c进化枝中的其他四种疫霉密切相关，包括菜豆疫霉、甘薯疫霉、奇异疫霉和安第斯疫霉，它们是其他野生和驯化寄主的重要病原体。安第斯疫霉是致病疫霉与一种未知疫霉物种之间的种间杂种。我们对致病疫霉姐妹物种的线粒体基因组进行了测序，并研究了进化枝内的进化关系。系统发育分析表明，菜豆疫霉线粒体谱系是进化枝内的基部谱系。奇异疫霉和甘薯疫霉是姐妹谱系，与安第斯疫霉的Ic线粒体谱系有共同祖先。这些谱系依次是致病疫霉和安第斯疫霉Ia线粒体谱系的姐妹。安第斯疫霉Ic谱系比安第斯疫霉Ia线粒体谱系和致病疫霉分化得早得多。安第斯疫霉中两个线粒体谱系的存在支持了该物种的杂种性质。进化树中安第斯疫霉Ic谱系的祖先状态及其仅在厄瓜多尔、哥伦比亚和秘鲁的安第斯地区出现，表明该物种在自然界中的杂种起源可能发生在那里。
