Resistance to host conifer chemical defenses by bark beetles

树木对试图以它们为食的食草昆虫发动化学战。例如，当树皮甲虫攻击一棵树时，树立即开始将含有毒素的树脂扩散到它们身上。随着甲虫的持续攻击，树通常能够通过制造新的树脂化学物质来做出反应，这些化学物质的毒性甚至更大，以努力杀死甲虫或将它们赶出去。然而，通常情况下，甲虫在攻击中获胜，树被杀死，因为甲虫进化出了有效解毒树脂化学物质的酶。其中一些酶被称为“细胞色素P450”，任何给定的昆虫物种都可能有许多不同种类的这些酶，每一种酶都帮助它解毒不同的植物化学物质。我的研究目的是发现细胞色素P450，这对树皮甲虫攻击针叶树很重要。我打算确定甲虫“开启”产生解毒酶的细胞色素P450基因，并描述酶解毒树树脂化学物质的机制。有了这些知识，就有可能设计出只对某些种类的树皮甲虫抑制特定酶的杀虫剂。这种类型的杀虫剂会使甲虫更容易受到宿主树毒素的影响，因此树可以更频繁地“赢得”与甲虫的战斗。由于杀虫剂被设计成只针对一种甲虫的一种或两种酶，所以它不会对其他重要的森林生物产生影响。此外，更好地了解哪些树脂化学物质是足够危险的，树皮甲虫会花费相当大的能量来解毒这种化合物，这将有助于树木育种者努力生产更能抵抗树皮甲虫攻击的针叶树。

Trees wage chemical warfare upon the herbivorous insects that try to feed on them.  For instance, when  bark beetles attack a tree, the tree immediately begins to spread resin, which contains toxins, onto them.  As the attack by the beetles continues, the tree is often able to respond by manufacturing new resin chemicals that are even more toxic in an effort to kill the beetles or to drive them out.  Often, however, the beetles prevail in their attack and the tree is killed, because the beetles have evolved enzymes that effectively detoxify the resin chemicals.  Some of these enzymes are called "cytochromes P450" and any given insect species likely has many different varieties of these enzymes, which each help it to detoxify different plant chemicals.  The intent of my research is to discover the cytochromes P450 that are important to bark beetles attacking conifers.  I intend to both identify cytochrome P450 genes that the beetles "turn on" to produce the detoxification enzymes and to characterize the mechanisms by which the enzymes detoxify the tree resin chemicals.  With this knowledge, it might be possible to design pesticides that inhibit specific enzymes in only certain species of bark beetles.  This type of pesticide would make the beetles more susceptible to the host tree toxins, and thus the tree could "win" the battle with the beetles more often. Since the pesticide would be designed to be very specific to just one or two enzymes in a particular species of beetle, it would not have effects on other important forest organisms.  In addition, a better understanding of which resin chemicals are sufficiently dangerous that a bark beetle will expend considerable energy to detoxify the compound will assist tree breeders in their efforts to produce conifers that are more resistant to bark beetle attack.