Independent evolution of ancestral and novel defenses in a genus of toxic plants (Erysimum, Brassicaceae)
Independent evolution of ancestral and novel defenses in a genus of toxic plants (Erysimum, Brassicaceae)
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DOI：
10.7554/elife.51712
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发表时间：
2020-04
期刊：
影响因子：
7.7
通讯作者：
Tobias Züst;S. Strickler;Adrian F. Powell;Makenzie E. Mabry;H. An;M. Mirzaei;T. York;Cynthia K Holland;Pavan Kumar;Matthias Erb;Georg Petschenka;J. Gómez;F. Perfectti;C. Müller;J. C. Pires;Lukas A Mueller;G. Jander
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作者：
Tobias Züst;S. Strickler;Adrian F. Powell;Makenzie E. Mabry;H. An;M. Mirzaei;T. York;Cynthia K Holland;Pavan Kumar;Matthias Erb;Georg Petschenka;J. Gómez;F. Perfectti;C. Müller;J. C. Pires;Lukas A Mueller;G. Jander
植物化学多样性被认为是共同进化周期的结果，因为草食动物的专门化对植物化学防御施加了多样化的选择。十字花科植物属(Erysimum)中的植物既产生祖先的硫代葡萄糖苷，又产生进化上新的腰果内酯作为防御。在这里，我们测试宏观进化假说的共同表达，共同调节，和多样化的这些潜在的冗余防御整个属。我们测序和组装了菊花的基因组和另外47个种的叶片转录本，从9868个同源基因构建了一个系统发育树，揭示了几个地理分支，但也显示了高度的基因不一致。这两种防御的浓度、诱导性和多样性在物种之间是独立的，没有权衡取舍的证据。密切相关的、地理上共同出现的物种具有相似的肉豆内酯特征，但不具有硫代葡萄糖苷特征，这可能是由于作用于每个防御系统的特定选择压力的结果。因此，Erysimum中的祖先和新的化学防御似乎提供了补充而不是多余的功能。
Phytochemical diversity is thought to result from coevolutionary cycles as specialization in herbivores imposes diversifying selection on plant chemical defenses. Plants in the speciose genus Erysimum (Brassicaceae) produce both ancestral glucosinolates and evolutionarily novel cardenolides as defenses. Here we test macroevolutionary hypotheses on co-expression, co-regulation, and diversification of these potentially redundant defenses across this genus. We sequenced and assembled the genome of E. cheiranthoides and foliar transcriptomes of 47 additional Erysimum species to construct a phylogeny from 9868 orthologous genes, revealing several geographic clades but also high levels of gene discordance. Concentrations, inducibility, and diversity of the two defenses varied independently among species, with no evidence for trade-offs. Closely related, geographically co-occurring species shared similar cardenolide traits, but not glucosinolate traits, likely as a result of specific selective pressures acting on each defense. Ancestral and novel chemical defenses in Erysimum thus appear to provide complementary rather than redundant functions.