Division of Plant Sciences, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA.
Department of Environmental Sciences, Bowman-Oddy Laboratories, University of Toledo, Toledo, OH, 43606, USA.
Sci Rep. 2019 Feb 12;9(1):1833. doi: 10.1038/s41598-018-38475-6.
Many insect species have acquired the ability to redirect plant development to form unique organs called galls, which provide these insects with unique, enhanced food and protection from enemies and the elements. Many galls resemble flowers or fruits, suggesting that elements of reproductive development may be involved. We tested this hypothesis using RNA sequencing to quantify the transcriptional responses of wild grapevine (Vitis riparia) leaves to a galling parasite, phylloxera (Daktulosphaira vitifoliae). If development of reproductive structures is part of gall formation, we expected to find significantly elevated expression of genes involved in flower and/or fruit development in developing galls as opposed to ungalled leaves. We found that reproductive gene ontology categories were significantly enriched in developing galls, and that expression of many candidate genes involved in floral development were significantly increased, particularly in later gall stages. The patterns of gene expression found in galls suggest that phylloxera exploits vascular cambium to provide meristematic tissue and redirects leaf development towards formation of carpels. The phylloxera leaf gall appears to be phenotypically and transcriptionally similar to the carpel, due to the parasite hijacking underlying genetic machinery in the host plant.
许多昆虫物种已经获得了重新定向植物发育的能力，形成了独特的器官，称为虫瘿，这些器官为昆虫提供了独特的、增强的食物，并保护它们免受敌人和自然环境的侵害。许多虫瘿类似于花或果实，这表明生殖发育的某些元素可能参与其中。我们使用 RNA 测序来量化野生葡萄（Vitis riparia）叶片对寄生性瘿蚊（Daktulosphaira vitifoliae）的转录反应，以此来验证这一假设。如果生殖结构的发育是形成虫瘿的一部分，我们预计在发育中的虫瘿中会发现参与花和/或果实发育的基因表达显著升高，而在未受瘿蚊侵害的叶片中则不会。我们发现，发育中的虫瘿中生殖基因本体论类别显著富集，许多参与花发育的候选基因的表达显著增加，尤其是在后期的虫瘿阶段。在虫瘿中发现的基因表达模式表明，瘿蚊利用维管形成层为分生组织提供营养，并将叶片发育方向转向心皮的形成。由于寄生虫劫持了宿主植物的潜在遗传机制，因此，叶瘿的表型和转录与心皮相似。
