Mechanisms by Which Root Disease Induced Changes in Ponderosa Pine Physiology Effect Bark Beetle Behavior

9630934树木对根部病原体的生理反应，以及由此产生的对植物取食昆虫行为的影响，人们知之甚少。1)黄松根真菌病(Heterobasidion Annosum)引起的生化变化，着重于未受真菌侵染的部分树的诱导变化(即系统诱导)。初步证据表明，发生了全身反应，特别是对二苯乙烯类物质，这些物质与疾病症状的发展有关。将进行温室和田间实验，以进一步描述这种在针叶树中意想不到的新现象。2)寄主对根部病原物的反应产生的化合物(包括二苯乙烯类和乙烯等)以及病原菌本身对树皮甲虫行为的影响。在寄主树对根部病原体的生理反应中产生的化合物作为引诱剂和/或取食刺激剂的作用将在实验室和田间确定，以便更好地了解这些树皮甲虫是如何检测适合定殖的寄主组织的。这项工作将极大地促进我们对基本生态生理相互作用的了解，整合各种伙伴，如真菌病原体、林木和相关的树皮甲虫。对这三种相互作用的更多了解也将最终导致对其他植物/草食系统的更多了解，并为阐明寄主对草食动物的抗性的生理机制提供基础。因此，基于对树木衰退和寄主生理病理学在树皮甲虫定殖中的作用的更好的了解，这项研究还可能导致对森林疾病和树皮甲虫管理的改进策略。

9630934 Wood The physiological responses of trees to root pathogens, and the resulting effects on plant-feeding insect behavior are poorly understood. The studies outlined here aim to characterize: 1) the biochemical changes in ponderosa pine (Pinus ponderosa) in response to annosus root disease (Heterobasidion annosum), emphasizing induced changes in parts of the tree not infected by the fungus (i.e., systematic induction). Preliminary evidence indicates that a systemic response occurs, especially with respect to stilbenes, and that these substances are associated with development of disease symptoms. Greenhouse and field experiments will be carried out to further characterize this unexpected and novel phenomenon in conifers. 2) the influence of compounds produced by the host in response to the root pathogen (including stilbenes and ethylene, among others), and by the pathogen itself, on bark beetle behavior mountain pine beetle (Dendroctonus ponderosae) and the western pine beetle (D. brevicomis) (Coleoptera: Scolytidae) . The role of compounds produced during the physiological response of the host tree to the root pathogen as attractants and/or feeding stimulants will be determined in the laboratory and the field, in order to better understand how these bark beetles detect suitable host tissue for colonization. This work will significantly advance our knowledge of fundamental ecophysiological interactions, integrating partners as diverse as fungal pathogens, forest trees, and associated bark beetles. A greater knowledge of this three way interaction will also ultimately lead to a greater understanding of other plant/herbivore systems and provide the basis for elucidating the physiological mechanisms of host resistance to herbivores. Hence, this investigation may also result in modified strategies for forest disease and bark beetle man agement, based on better knowledge of tree decline and the role of host physiopathology in bark beetle colonization.