Genetic analysis of floral symmetry in Van Gogh's sunflowers reveals independent recruitment of CYCLOIDEA genes in the Asteraceae.
Genetic analysis of floral symmetry in Van Gogh's sunflowers reveals independent recruitment of CYCLOIDEA genes in the Asteraceae.
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DOI：
10.1371/journal.pgen.1002628
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发表时间：
2012
期刊：
影响因子：
4.5
通讯作者：
Burke JM
中科院分区：
文献类型：
--
作者：
Chapman MA;Tang S;Draeger D;Nambeesan S;Shaffer H;Barb JG;Knapp SJ;Burke JM
花对称的遗传基础是一个非常有趣的话题，因为它影响传粉者的行为，从而导致植物多样性。菊科是开花植物中最大的一科，是研究这一特征的理想系统，因为该科中的许多物种都表现出包含两侧对称(即左右对称)和径向对称(即辐射对称)小花的复合花序。在向日葵及其近缘种中，花序由一轮伞状小花围绕着多轮花盘小花组成。我们发现，在双花(DBL)向日葵突变体(其中圆盘小花发展成双边对称)中，例如文森特·梵高在他著名的19世纪向日葵绘画中捕捉到的那些突变体中，通常在WT射线中特异表达的环状病毒(CyC)类基因(HaCyC2c)的启动子区域的插入反而在整个花序中表达，这可能导致了观察到的辐射形态学的丧失。同样的基因在两个独立的管状射线(Tub)突变体中发生突变，尽管这些突变显然涉及最近的转座子插入，导致正常同形的射线小花很少或几乎没有表达和辐射。有趣的是，对整个家族的类CyC基因的系统发育分析表明，这个迷人的基因家族的不同平行基因已经被独立招募来确定菊科不同物种的同型。植物生物学家对花朵形状和对称性的进化非常感兴趣，因为它会影响传粉者的行为。菊科开花植物的花冠可以包含两侧和径向对称的花。在这项研究中，我们发现了一个类似于环科动物的基因，它负责决定向日葵的花对称性。这个基因的错误表达导致了一个双花的表型，类似于文森特·梵高在19世纪的著名画作中捕捉到的那些，而基因功能的丧失导致正常的两侧对称的射线小花的放射化。有趣的是，这个基因与菊科其他成员中负责花对称的环科类基因并不是同源的，这为同一基因家族的不同成员为相同的功能平行招募提供了证据。
The genetic basis of floral symmetry is a topic of great interest because of its effect on pollinator behavior and, consequently, plant diversification. The Asteraceae, which is the largest family of flowering plants, is an ideal system in which to study this trait, as many species within the family exhibit a compound inflorescence containing both bilaterally symmetric (i.e., zygomorphic) and radially symmetric (i.e., actinomorphic) florets. In sunflower and related species, the inflorescence is composed of a single whorl of ray florets surrounding multiple whorls of disc florets. We show that in double-flowered (dbl) sunflower mutants (in which disc florets develop bilateral symmetry), such as those captured by Vincent van Gogh in his famous nineteenth-century sunflower paintings, an insertion into the promoter region of a CYCLOIDEA (CYC)-like gene (HaCYC2c) that is normally expressed specifically in WT rays is instead expressed throughout the inflorescence, presumably resulting in the observed loss of actinomorphy. This same gene is mutated in two independent tubular-rayed (tub) mutants, though these mutations involve apparently recent transposon insertions, resulting in little or no expression and radialization of the normally zygomorphic ray florets. Interestingly, a phylogenetic analysis of CYC-like genes from across the family suggests that different paralogs of this fascinating gene family have been independently recruited to specify zygomorphy in different species within the Asteraceae. The evolution of flower shape and symmetry is of great interest to plant biologists, because it can affect pollinator behavior. Species in the flowering plant family Asteraceae exhibit flower heads that can contain both bilaterally and radially symmetric flowers. In this study, we identify a CYCLOIDEA-like gene that is responsible for determining flower symmetry in sunflower. Mis-expression of this gene causes a double-flowered phenotype, similar to those captured in Vincent van Gogh's famous nineteenth-century paintings, whereas loss of gene function causes radialization of the normally bilaterally symmetric ray florets. Interestingly, this gene is not orthologous to the CYCLOIDEA-like gene responsible for floral symmetry in other members of the Asteraceae, providing evidence of the parallel recruitment of different members of the same gene family for the same function.
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DOI：
10.1073/pnas.0801359105
发表时间：
2008-07-01
影响因子：
11.1
作者：
Broholm, Suvi K.;Tahtiharju, Sari;Elomaa, Paula
通讯作者：
Elomaa, Paula
DOI：
10.1073/pnas.94.8.3817
发表时间：
1997-04-15
影响因子：
11.1
作者：
Chen, LB;DeVries, AL;Cheng, CHC
通讯作者：
Cheng, CHC
影响因子：
2.6
作者：
Fambrini, M;Bertini, D;Pugliesi, C
通讯作者：
Pugliesi, C
影响因子：
2.3
作者：
Howarth, DG;Donoghue, MJ
通讯作者：
Donoghue, MJ
影响因子：
3.1
作者：
FICK, GN
通讯作者：
FICK, GN