Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, 750 07 Uppsala, Sweden.
J Chem Ecol. 2013 Apr;39(4):516-24. doi: 10.1007/s10886-013-0266-3. Epub 2013 Mar 1.
The genotype of the plant determines, through the expression of the phenotype, how well it is suited as food for herbivores. Since hybridization often results in profound genomic alterations with subsequent changes in phenotypic traits, it has the potential to significantly affect plant-herbivore interactions. In this study, we used a population of F2 hybrids that originated from a cross between a Salix viminalis and a Salix dasyclados genotype, which differed in both phenolic content and resistance to the herbivorous leaf beetle Phratora vulgatissima. We screened for plants that showed a great variability in leaf beetle performance (i.e., oviposition and survival). By correlating leaf phenolics to the response of the herbivores, we evaluated the importance of different phenolic compounds for Salix resistance to the targeted insect species. The performance of P. vulgatissima varied among the F2 hybrids, and two patterns of resistance emerged: leaf beetle oviposition was intermediate on the F2 hybrids compared to the parental genotypes, whereas leaf beetle survival demonstrated similarities to one of the parents. The findings indicate that these life history traits are controlled by different resistance mechanisms that are inherited differently in the hybrids. Salicylates and a methylated luteolin derivative seem to play major roles in hybrid resistance to Phratora vulgatissima. Synergistic effects of these compounds, as well as potential threshold concentrations, are plausible. In addition, we found considerable variation in both distributions and concentrations of different phenolics in the F2 hybrids. The phenolic profiles of parental genotypes and F2 hybrids differed significantly (e.g., novel compounds appeared in the hybrids) suggesting genomic alterations with subsequent changes in biosynthetic pathways in the hybrids.
植物的基因型通过表型的表达决定了它作为食草动物食物的适宜程度。由于杂交通常会导致基因组的深刻改变，并随后改变表型特征，因此它有可能显著影响植物-食草动物的相互作用。在这项研究中，我们使用了源自柳属 viminalis 和柳属 dasyclados 基因型之间杂交的 F2 杂种群体，这两个基因型在酚类含量和对食草性叶甲 Phratora vulgatissima 的抗性方面存在差异。我们筛选了表现出叶甲表现出极大变异性的植物（即产卵和存活）。通过将叶片酚类物质与食草动物的反应相关联，我们评估了不同酚类化合物对柳属植物抵抗目标昆虫物种的重要性。P. vulgatissima 在 F2 杂种中的表现存在差异，并且出现了两种抗性模式：与亲本基因型相比，叶甲的产卵在 F2 杂种中处于中间水平，而叶甲的存活则与亲本之一相似。研究结果表明，这些生活史特征受不同的抗性机制控制，这些机制在杂种中以不同的方式遗传。水杨酸酯和甲基化的木樨草素衍生物似乎在柳属植物对 Phratora vulgatissima 的抗性中起主要作用。这些化合物的协同作用以及潜在的阈值浓度是合理的。此外，我们还发现 F2 杂种中不同酚类物质的分布和浓度存在相当大的差异。亲本基因型和 F2 杂种的酚类图谱差异显著（例如，在杂种中出现了新的化合物），这表明基因组发生了改变，并随后改变了杂种中的生物合成途径。
