Takei Mami, Yoshida Sayaka, Kawai Takashi, Hasegawa Morifumi, Suzuki Yoshihito
Department of Bioresource Science, College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki 300-0393, Japan.
Department of Bioresource Science, College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki 300-0393, Japan.
J Insect Physiol. 2015 Jan;72:43-51. doi: 10.1016/j.jinsphys.2014.11.006. Epub 2014 Nov 28.
Insect galls are abnormal plant tissues induced by external stimuli from parasitizing insects. It has been suggested that the stimuli include phytohormones such as auxin and cytokinins produced by the insects. In our study on the role of hormones in gall induction by the aphid Tetraneura nigriabdominalis, it was found that feedback regulation related to auxin and cytokinin activity is absent in gall tissues, even though the aphids contain higher concentrations of those phytohormones than do plant tissues. Moreover, jasmonic acid signaling appears to be compromised in gall tissue, and consequently, the production of volatile organic compounds, which are a typical defense response of host plants to herbivory, is diminished. These findings suggest that these traits of the gall tissue benefit aphids, because the gall tissue is highly sensitive to auxin and cytokinin, which induce and maintain it. The induced defenses against aphid feeding are also compromised. The abnormal responsiveness to phytohormones is regarded as a new type of extended phenotype of gall-inducing insects.
虫瘿是由寄生昆虫的外部刺激诱导形成的异常植物组织。有人认为，这些刺激包括昆虫产生的植物激素，如生长素和细胞分裂素。在我们关于激素在黑腹四脉绵蚜诱导虫瘿中的作用的研究中，发现虫瘿组织中不存在与生长素和细胞分裂素活性相关的反馈调节，尽管蚜虫体内这些植物激素的浓度高于植物组织。此外，茉莉酸信号传导在虫瘿组织中似乎受到损害，因此，作为宿主植物对食草动物典型防御反应的挥发性有机化合物的产生减少。这些发现表明，虫瘿组织的这些特性对蚜虫有利，因为虫瘿组织对诱导和维持它的生长素和细胞分裂素高度敏感。针对蚜虫取食的诱导防御也受到损害。对植物激素的异常反应被视为诱导虫瘿昆虫的一种新型扩展表型。
