Spontaneous mutations in KNOX genes give rise to a novel floral structure in Antirrhinum
Spontaneous mutations in KNOX genes give rise to a novel floral structure in Antirrhinum
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DOI：
10.1016/s0960-9822(02)00721-2
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发表时间：
2002-04-02
期刊：
影响因子：
9.2
通讯作者：
Hudson, A
中科院分区：
文献类型：
--
作者：
Golz, JF;Keck, EJ;Hudson, A
背景资料：花瓣短枝收集花蜜的管状突起被认为是关键的创新，因为它们能够改变传粉者的特异性，从而导致生殖隔离和物种形成。在许多分类群中，刺已经频繁而迅速地出现。为了测试其潜在的起源，我们在两个位点，HIRZ和INA，导致新的产物金鱼草花瓣，类似的花瓣刺密切相关generation.Results：HIRZ和INA分离和编码类似的KNOX同源结构域蛋白，通常只在顶端分生组织表达，并可能采取冗余的自发显性突变。这两种显性突变都是由转座子插入非编码区引起的，引起功能转录本的异位表达，无论是在花瓣中还是在具有多效性效应的所有侧部器官中。形成一个马刺样的产物，这类似于一个异位花瓣管，是依赖于KNOX基因的表达和背腹侧的不对称的flower.Conclusions：这些突变提供了一个例子，如何花瓣马刺可能会迅速演变，由于调节基因表达的变化。
Background: Petal spurs-tubular outgrowths that collect nectar-are considered key innovations because of their ability to change pollinator specificity and so cause reproductive isolation and speciation. Spurs have arisen frequently and rapidly in many taxa. To test their potential origins, we isolated spontaneous dominant mutations at two loci, HIRZ and INA, that cause novel outgrowths from Antirrhinum petals, resembling the petal spurs of closely related genera.Results: HIRZ and INA were isolated and shown to encode similar KNOX homeodomain proteins that are normally expressed only in apical meristems and are likely to act redundantly. Both dominant mutations were caused by transposon insertions in noncoding regions that caused ectopic expression of functional transcripts, either in petals or in all lateral organs with more pleiotropic effects. Formation of a spur-like outgrowth, which resembled an ectopic petal tube, was dependent both on KNOX gene expression and dorsiventral asymmetry of the flower.Conclusions: These mutations provide an example of how petal spurs might evolve rapidly due to changes in regulatory gene expression.