Transposon-induced gene activation as a mechanism generating cluster shape somatic variation in grapevine
Transposon-induced gene activation as a mechanism generating cluster shape somatic variation in grapevine
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DOI：
10.1111/j.1365-313x.2009.04090.x
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发表时间：
2010-02-01
期刊：
影响因子：
7.2
通讯作者：
Martinez-Zapater, Jose M.
中科院分区：
文献类型：
--
作者：
Fernandez, Lucie;Torregrosa, Laurent;Martinez-Zapater, Jose M.
我们鉴定了葡萄品种Carignan的重复生殖分生组织(RRM)体细胞变异表型的遗传和分子起源。在这里，我们表明，在这种体细胞变异中观察到的极端丛生增殖和延迟开花是由单一显性突变引起的。Carignan和RRM植株在花序发育早期的转录图谱表明，一些调控基因在RRM花序中过表达，包括VvTFL1A，一个与拟南芥TFL1相近的同源物。遗传和分子分析表明，在VvTFl1a启动子中插入了第II类转座元件Hatvine1-RRM，与相应的VvTFl1a等位基因在茎尖的生殖和营养器官中上调有关。这些结果表明，这个TFL1葡萄同源基因在决定花序结构方面发挥了作用，对葡萄果串的大小和分枝模式具有关键影响。我们的结果证明了葡萄植物中存在由第二类转座元件引起的自发顺式激活过程，并指出它们可能是多年生植物体细胞变异的一种机制。这一机制预计将在嵌合部门产生显性表型，这些嵌合部门很容易受到自然选择的影响。
We have characterized the genetic and molecular origin of the reiterated reproductive meristem (RRM) somatic variant phenotype of grapevine cultivar Carignan. Here, we show that the extreme cluster proliferation and delayed anthesis observed in this somatic variant is caused by a single dominant mutation. Transcriptional profiling of Carignan and RRM plants during early stages of inflorescence development demonstrated the overexpression of a few regulatory genes, including VvTFL1A, a close TFL1 Arabidopsis homolog, in RRM inflorescences. Genetic and molecular analyses correlated the insertion of a class-II transposable element, Hatvine1-rrm, in the VvTFL1A promoter, with upregulation of the corresponding VvTFL1A allele in reproductive and vegetative organs of the shoot apex. These results suggest a role for this TFL1 grapevine homolog in the determination of inflorescence structure, with a critical effect on the size and branching pattern of grapevine fruit clusters. Our results demonstrate the existence of spontaneous cis-activation processes caused by class-II transposable elements in grapevine plants, and point to their possible role as a mechanism to generate somatic cell variation in perennial plants. This mechanism is expected to generate dominant phenotypes in chimeric sectors that can be readily exposed to natural selection.