Tanaka Yuichiro, Okada Koichi, Asami Tadao, Suzuki Yoshihito
Department of Bioresource Science, Ibaraki University.
Biosci Biotechnol Biochem. 2013;77(9):1942-8. doi: 10.1271/bbb.130406. Epub 2013 Sep 7.
A variety of insect species induce galls on host plants. Liquid chromatographic/tandem mass spectrometric analyses showed that a gall midge (Rhopalomyia yomogicola) that induces galls on Artemisia princeps contained high levels of indole-3-acetic acid and cytokinins. The gall midge larvae also synthesized indole-3-acetic acid from tryptophan. Close observation of gall tissue sections indicated that the larval chamber was surrounded by layers of cells having secondary cell walls with extensive lignin deposition, except for the part of the gall that constituted the feeding nutritive tissue which was composed of small cells negatively stained for lignin. The differences between these two types of tissue were confirmed by an expression analysis of the genes involved in the synthesis of the secondary cell wall. Phytohormones may have functioned in maintaining the feeding part of the gall as fresh nutritive tissue. Together with the results in our previous study, those presented here suggest the importance of phytohormones in gall induction.
多种昆虫会在寄主植物上诱导形成虫瘿。液相色谱/串联质谱分析表明，一种在魁蒿上诱导形成虫瘿的瘿蚊（艾蒿瘿蚊）含有高水平的吲哚 - 3 - 乙酸和细胞分裂素。瘿蚊幼虫也能从色氨酸合成吲哚 - 3 - 乙酸。对虫瘿组织切片的仔细观察表明，幼虫腔被具有次生细胞壁且有大量木质素沉积的细胞层包围，除了构成取食营养组织的那部分虫瘿，该营养组织由对木质素呈负染色的小细胞组成。通过对参与次生细胞壁合成的基因进行表达分析，证实了这两种组织类型之间的差异。植物激素可能在维持虫瘿的取食部分作为新鲜营养组织方面发挥了作用。结合我们之前研究的结果，此处呈现的结果表明植物激素在虫瘿诱导中的重要性。
