The Genetic Architecture of Plant Defense Trade-offs in a Common Monkeyflower
The Genetic Architecture of Plant Defense Trade-offs in a Common Monkeyflower
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普通猴花植物防御权衡的遗传结构
DOI：
10.1093/jhered/esaa015
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发表时间：
2020
影响因子：
3.1
通讯作者：
Hodges, Scott
中科院分区：
文献类型：
--
作者：
Kooyers, Nicholas J;Donofrio, Abigail;Blackman, Benjamin K;Holeski, Liza M;Hodges, Scott
要确定性状的适应性组合是如何产生的，就需要了解遗传约束的普遍性和范围。经常观察到的植物生长，防御和/或繁殖时间之间的表型相关性，使研究人员提出，多效性或影响独立性状的变体之间的强遗传连锁是普遍存在的。或者，这些相关性可能是通过每个性状的不同基因的独立突变和广泛的相关选择而产生的。在这里，我们评估这些替代品进行的数量性状位点（QTL）定位实验，涉及2个人口之间的杂交普通monkeyflower（Mimulus guttatus），不同的生长速度，以及总浓度和阿森纳组成的植物防御化合物，苯丙素苷（PPG）。我们没有发现证据表明多效性是防御和生长率之间相关性的基础。然而，总PPG水平和开花时间之间存在很强的遗传相关性，这在很大程度上归因于单个共享QTL。虽然这一结果表明多效性/紧密连锁的作用，其他几个QTL也有助于总PPG的变化。此外，不同的PPG库受到许多较小效应QTL的影响，每个QTL都是1或2个PPG变异的基础。这一结果表明，化学防御武库可以很好地适应生物环境，尽管共享一个共同的生化前体。总之，我们的研究结果表明，防御和生活史性状之间的相关性受到多效性或遗传连锁的影响，但遗传约束可能对未来的进化反应的影响有限，因为每个性状的变异的很大一部分是由独立的基因座控制的。
Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL. While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs. This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.