Still armed after domestication? Impacts of domestication and agronomic selection on silicon defences in cereals
Still armed after domestication? Impacts of domestication and agronomic selection on silicon defences in cereals
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DOI：
10.1111/1365-2435.12935
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发表时间：
2017-11
影响因子：
5.2
通讯作者：
Kimberley J. Simpson;R. Wade;M. Rees;C. Osborne;S. Hartley
中科院分区：
文献类型：
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作者：
Kimberley J. Simpson;R. Wade;M. Rees;C. Osborne;S. Hartley
《功能生态学》由John Wiley & Sons Ltd代表英国生态学会出版。植物表型反映了竞争性资源密集型生理过程之间的权衡。通过植物驯化，预计资源分配将从抗草食动物防御转向生长和繁殖，这样作物比其野生祖先生长更快，产量更高。据推测，这些变化是以国防投资为代价的，使作物“因驯化而解除武装”。硅是草的主要抗草食动物防御，包括我们许多最重要的主食谷物作物，但驯化对硅基防御的影响尚不清楚。我们测量了驯化和现代农艺选择对生长速度和一套抗草食动物防御措施的影响，特别是叶片韧性，硅和酚类浓度。我们对野生、地方品种和现代栽培谷物进行了比较，包括小麦、大麦和玉米，取样了8个独立的驯化事件和5个现代农艺选择的例子。叶片硅浓度表现出一个小的，但显着的，通过驯化减少10%，但没有现代农艺选择的影响，酚类浓度不受任何因素。硅浓度与叶片抗张强度呈正相关，但与叶片酚类物质浓度呈负相关，表明化学和物理防御之间的权衡。大小标准化的增长率是独立的驯化状态，并没有权衡硅或酚防御。然而，模型显示，在硅含量较高的植物中，相对生长速度随着尺寸的增加而减慢，因此它们达到了较小的最终尺寸，这意味着硅基防御的成本。我们发现了相反的模式酚为基础的防御，增加酚浓度与成熟时更大的植物大小，更快的最大相对生长速率。通过驯化，硅基防御在谷物中已经减少，与我们预测的这些防御对生长的成本一致。然而，现代农艺选择并没有影响硅防御谷类作物和硅浓度的小幅度下降与驯化不太可能有重大影响的能力，谷物承受一系列的非生物和生物胁迫。这些发现对作物保护和我们对植物权衡的理解具有广泛的意义。本文提供了一个简单的语言摘要。(http wiley.com/doi/10.1111/1365-2435.12935/suppinfo）。
Functional Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. Plant phenotypes reflect trade-offs between competing resource-intensive physiological processes. A shift in resource allocation, away from anti-herbivore defences and towards growth and reproduction, is predicted through plant domestication, such that crops are faster growing and higher yielding than their wild ancestors. These changes are hypothesized to have come at the cost of defence investment, leaving crops “disarmed by domestication”. Silicon is the principal anti-herbivore defence in grasses, including many of our most important staple cereal crops, but the impact of domestication on silicon-based defences is unknown. We measured the effects of both domestication and modern agronomic selection on growth rate and a suite of anti-herbivore defences, specifically leaf toughness, silicon and phenolic concentrations. Our comparison of wild, landrace and modern cultivated cereals spanned multiple cereal species, including wheat, barley and maize, sampling eight independent domestication events and five examples of modern agronomic selection. Leaf silicon concentration showed a small, but significant, 10% reduction through domestication, but there was no effect of modern agronomic selection, and phenolic concentration was not affected by either factor. Silicon concentration correlated positively with leaf tensile strength, but negatively with foliar phenolic concentrations, suggesting a trade-off between chemical and physical defences. Size-standardized growth rate was independent of domestication status, and did not trade-off with silicon or phenolic defences. However, modelling showed that relative growth rate slowed more with increasing size in plants with higher silicon levels, so that they reached a smaller final size, implying a cost of silicon-based defence. We found the opposite pattern for phenolic-based defence, with increasing phenolic concentrations associated with a greater plant size at maturity, and faster maximum relative growth rates. Silicon-based defences have been reduced in cereals through domestication, consistent with our predicted costs of these defences to growth. However, modern agronomic selection has not influenced silicon defences in cereal crops and the small decrease in silicon concentration associated with domestication is unlikely to have a major effect on the ability of cereals to withstand a range of abiotic and biotic stresses. These findings have broad implications for crop protection and our understanding of plant trade-offs. A plain language summary is available for this article. (http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12935/suppinfo).