The avocado genome informs deep angiosperm phylogeny, highlights introgressive hybridization, and reveals pathogen-influenced gene space adaptation
The avocado genome informs deep angiosperm phylogeny, highlights introgressive hybridization, and reveals pathogen-influenced gene space adaptation
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DOI：
10.1073/pnas.1822129116
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发表时间：
2019-08-20
影响因子：
11.1
通讯作者：
Herrera-Estrella, Luis
中科院分区：
文献类型：
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作者：
Rendon-Anaya, Martha;Ibarra-Laclette, Enrique;Herrera-Estrella, Luis
鳄梨，Persea americana，是一种对墨西哥农业非常重要的水果作物，全球需求量不断增加。鳄梨属于被子植物木兰科分支，与真双子叶植物和单子叶植物的系统发育位置存在争议。我们对墨西哥鳄梨品种P. americana var. drymifolia，和最商业化流行的杂交品种，哈斯，并锚定后者的染色体使用遗传图谱。危地马拉和西印度群岛品种的重测序显示，类似于39%的哈斯基因组代表危地马拉来源地区渗入到墨西哥种族背景。一些基因渗入块非常大，与该品种的最近起源一致。鳄梨谱系在其进化史上经历了2次谱系特异性多倍体事件。虽然基因树/物种树的基因组结果是不确定的，同线的直系同源物距离其他物种的地方鳄梨作为姐妹的巨大的单子叶植物和真双子叶植物血统的组合。重复基因下降多倍体增加鳄梨转录因子的多样性，而串联重复增强物种的次生代谢。已知由鳄梨炭疽病病原体感染引起的苯丙素类生物合成是串联体中的一种富集功能。此外，转录组数据显示，串联重复显着上调和下调炭疽感染的反应，而多倍体重复没有，支持的一般观点，即串联重复的集合有助于进化最近的“调谐旋钮”在基因组适应景观的给定物种。
The avocado, Persea americana, is a fruit crop of immense importance to Mexican agriculture with an increasing demand worldwide. Avocado lies in the anciently diverged magnoliid clade of angiosperms, which has a controversial phylogenetic position relative to eudicots and monocots. We sequenced the nuclear genomes of the Mexican avocado race, P. americana var. drymifolia, and the most commercially popular hybrid cultivar, Hass, and anchored the latter to chromosomes using a genetic map. Resequencing of Guatemalan and West Indian varieties revealed that similar to 39% of the Hass genome represents Guatemalan source regions introgressed into a Mexican race background. Some introgressed blocks are extremely large, consistent with the recent origin of the cultivar. The avocado lineage experienced 2 lineage-specific polyploidy events during its evolutionary history. Although gene-tree/species-tree phylogenomic results are inconclusive, syntenic ortholog distances to other species place avocado as sister to the enormous monocot and eudicot lineages combined. Duplicate genes descending from polyploidy augmented the transcription factor diversity of avocado, while tandem duplicates enhanced the secondary metabolism of the species. Phenylpropanoid biosynthesis, known to be elicited by Colletotrichum (anthracnose) pathogen infection in avocado, is one enriched function among tandems. Furthermore, transcriptome data show that tandem duplicates are significantly up- and down-regulated in response to anthracnose infection, whereas polyploid duplicates are not, supporting the general view that collections of tandem duplicates contribute evolutionarily recent "tuning knobs" in the genome adaptive landscapes of given species.