Expression of B-class MADS-box genes in response to variations in photoperiod is associated with chasmogamous and cleistogamous flower development in Viola philippica
Expression of B-class MADS-box genes in response to variations in photoperiod is associated with chasmogamous and cleistogamous flower development in Viola philippica
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B 类 MADS-box 基因响应光周期变化的表达与紫花地丁的开花和闭锁花发育相关
DOI：
10.1186/s12870-016-0832-2
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发表时间：
2016-07-07
影响因子：
5.3
通讯作者：
He, Chaoying
中科院分区：
文献类型：
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作者：
Li, Qiaoxia;Huo, Qingdi;He, Chaoying
背景：一些植物发展出一种繁殖系统，既能产生杂交花(CH)，又能产生闭合花(CL)。结果：在本研究中，我们观察到蝴蝶兰在短日照的情况下发育CH花，而延长的光周期诱导中间CL和CL花的形成。在长日照条件下，花瓣和雄蕊的数目和大小均低于正常发育的CH花，并且至少14h的光照诱导的完全CL花没有花瓣，但形成两个雄蕊育性降低。花的ABC模型表明，B类MADS-box基因在很大程度上影响着受影响的双轮花器官的发育；因此，我们重点研究了这些基因在菲律宾葡萄中的特征，以了解这种特殊的发育转换。分离到3个这样的基因，分别命名为VpTM6-1、VpTM6-2和VpPI。在花的发育过程中(特别是在花瓣和雄蕊中)，这些基因均有不同程度的表达，其中CH花的表达水平最高，中花的表达水平较低，CL花的表达水平最低。花诱导和器官发生后表达水平的变化明显地响应于光周期的变化。结论：花瓣和雄蕊的发育受到抑制可能是由于长日照下调了B类MADS-box基因的表达，从而诱导了CL花的产生。我们的工作有助于理解植物二形花的适应性进化形成。
Background: Some plants develop a breeding system that produces both chasmogamous (CH) and cleistogamous (CL) flowers. However, the underlying molecular mechanism remains elusive.Results: In the present study, we observed that Viola philippica develops CH flowers with short daylight, whereas an extended photoperiod induces the formation of intermediate CL and CL flowers. In response to long daylight, the respective number and size of petals and stamens was lower and smaller than those of normally developed CH flowers, and a minimum of 14-h light induced complete CL flowers that had no petals but developed two stamens of reduced fertility. The floral ABC model indicates that B-class MADS- box genes largely influence the development of the affected two-whorl floral organs; therefore, we focused on characterizing these genes in V. philippica to understand this particular developmental transition. Three such genes were isolated and respectively designated as VpTM6-1, VpTM6-2, and VpPI. These were differentially expressed during floral development (particularly in petals and stamens) and the highest level of expression was observed in CH flowers; significantly low levels were detected in intermediate CL flowers, and the lowest level in CL flowers. The observed variations in the levels of expression after floral induction and organogenesis apparently occurred in response to variations in photoperiod.Conclusions: Therefore, inhibition of the development of petals and stamens might be due to the downregulation of B-class MADS- box gene expression by long daylight, thereby inducing the generation of CL flowers. Our work contributes to the understanding of the adaptive evolutionary formation of dimorphic flowers in plants.