Cipollini Donald F, Busch Jeremiah W, Stowe Kirk A, Simms Ellen L, Bergelson Joy
Department of Ecology and Evolution, The University of Chicago, 1101 E. 57th St., Chicago, Illinois 60637, USA.
J Chem Ecol. 2003 Feb;29(2):285-302. doi: 10.1023/a:1022673726325.
We examined genetic variation in inducibility and in constitutive and herbivore-induced levels of glucosinolates, trypsin inhibitors, and resistance to herbivory in families of Brassica rapa originating from a wild population. We also examined phenotypic and genetic correlations among absolute levels of these traits in control and induced plants. We grew seedlings of 10 half-sib families in pairs in pots, and exposed one plant per pair to folivory by Trichoplusia ni larvae. Two days later, we sampled all plants for total glucosinolate and trypsin inhibitor levels and examined the preference and consumption by T. ni larvae of previously damaged (induced) and undamaged (control) plants. There was no significant variation among sire families in the induction of glucosinolates or trypsin inhibitors by T. ni feeding. Total glucosinolate levels in either control or induced plants did not vary by family. In contrast, trypsin inhibitor levels in both control and induced plants varied significantly by family. Trichoplusia ni fed less on induced plants than on control plants in the bioassay, but neither the induction of resistance by prior T. ni feeding nor absolute levels of damage done to control and induced plants varied significantly by sire family. Temporal blocking strongly affected trypsin inhibitor levels and the response of some families in the bioassays. There were no significant phenotypic or genetic correlations of levels of glucosinolates or trypsin inhibitors with each other or with damage in either control or induced plants. Overall, these results suggest that in the B. rapa population that we studied, both total glucosinolate content and biological resistance to herbivory by T. ni was nonvariable and almost universally inducible by prior T. ni feeding. In contrast, control and induced levels of trypsin inhibitors varied genetically and have the capacity to respond to future selection imposed by herbivores. However, the role of these defenses in constitutive or induced resistance to T. ni in this species remains unclear.
我们研究了源自野生种群的白菜型油菜家系中芥子油苷、胰蛋白酶抑制剂的诱导性、组成型水平以及草食动物诱导水平，以及对草食性的抗性方面的遗传变异。我们还研究了对照植物和诱导植物中这些性状绝对水平之间的表型和遗传相关性。我们将10个半同胞家系的幼苗成对种植在花盆中，每对中的一株植株让烟芽夜蛾幼虫取食叶片。两天后，我们采集所有植株样本以测定总芥子油苷和胰蛋白酶抑制剂水平，并检测烟芽夜蛾幼虫对先前受损（诱导）和未受损（对照）植株的取食偏好和食量。烟芽夜蛾取食诱导产生的芥子油苷或胰蛋白酶抑制剂在父本家系间没有显著差异。对照植物或诱导植物中的总芥子油苷水平在各家族间没有变化。相比之下，对照植物和诱导植物中的胰蛋白酶抑制剂水平在家族间有显著差异。在生物测定中，烟芽夜蛾对诱导植物的取食量少于对照植物，但先前烟芽夜蛾取食诱导产生的抗性以及对照植物和诱导植物的绝对损伤水平在父本家系间均无显著差异。时间区组强烈影响胰蛋白酶抑制剂水平以及生物测定中一些家系的反应。在对照植物或诱导植物中，芥子油苷或胰蛋白酶抑制剂水平之间，以及它们与损伤之间均无显著的表型或遗传相关性。总体而言，这些结果表明，在我们研究的白菜型油菜种群中，总芥子油苷含量和对烟芽夜蛾草食性的生物抗性都是不变的，并且几乎都能被先前烟芽夜蛾的取食诱导产生。相比之下，对照和诱导条件下的胰蛋白酶抑制剂水平存在遗传变异，并且有能力响应草食动物未来施加的选择。然而，这些防御机制在该物种对烟芽夜蛾的组成型或诱导抗性中的作用仍不清楚。
