Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada.
Department of Statistics, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
New Phytol. 2019 Feb;221(3):1503-1517. doi: 10.1111/nph.15477. Epub 2018 Oct 23.
Conifers depend on complex defense systems against herbivores. Stone cells (SC) and oleoresin are physical and chemical defenses of Sitka spruce that have been separately studied in previous work. Weevil oviposit at the tip of the previous year's apical shoot (PYAS). We investigated interactions between weevil larvae and trees in controlled oviposition experiments with resistant (R) and susceptible (S) Sitka spruce. R trees have an abundance of SC in the PYAS cortex. SC are mostly absent in S trees. R trees and S trees also differ in the composition of oleoresin terpenes. Transcriptomes of R and S trees revealed differences in long-term weevil-induced responses. Performance of larvae was significantly reduced on R trees compared with S trees under experimental conditions that mimicked natural oviposition behavior at apical shoot tips and may be attributed to the effects of SC. In oviposition experiments designed for larvae to feed below the area of highest SC abundance, larvae showed an unusual feeding behavior and oleoresin appeared to function as the major defense. The results support a role for both SC and oleoresin terpenes and possible synergies between these traits in the defense syndrome of weevil-resistant Sitka spruce.
针叶树依赖于复杂的防御系统来抵御食草动物。石细胞（SC）和油树脂是云杉的物理和化学防御系统，之前的研究已经分别对其进行了研究。象鼻虫在去年的顶梢（PYAS）的尖端产卵。我们在具有抗性（R）和易感性（S）的云杉的受控产卵实验中，研究了象鼻虫幼虫和树木之间的相互作用。R 树在 PYAS 皮层中有大量的 SC。S 树上的 SC 几乎不存在。R 树和 S 树的油树脂萜烯组成也不同。R 树和 S 树的转录组显示出长期象鼻虫诱导反应的差异。在模拟顶梢自然产卵行为的实验条件下，与 S 树相比，幼虫在 R 树上的表现明显降低，这可能归因于 SC 的影响。在设计用于幼虫在 SC 丰度最高区域下方进食的产卵实验中，幼虫表现出异常的进食行为，油树脂似乎是主要的防御物质。结果支持 SC 和油树脂萜烯的作用以及这些特征在抗象鼻虫云杉防御综合征中的协同作用。
