An ortholog of MIXTA-like2 controls epidermal cell shape in flowers of Thalictrum
An ortholog of MIXTA-like2 controls epidermal cell shape in flowers of Thalictrum
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DOI：
10.1111/j.1469-8137.2009.02945.x
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发表时间：
2009-01-01
期刊：
影响因子：
9.4
通讯作者：
Connelly, Caitlin F.
中科院分区：
文献类型：
--
作者：
Di Stilio, Veronica S.;Martin, Cathie;Connelly, Caitlin F.
P>在这里，我们研究了唐松草（一种具有无花瓣花的毛茛科植物）与授粉相关的花表型的遗传基础。其他花器官中花瓣状特征的不同存在与昆虫与风授粉的不同适应相关。圆锥形细胞存在于昆虫授粉物种的萼片或雄蕊以及柱头中。我们对金鱼草转录因子 MIXTA-like2 的唐松草直向同源物进行了表征，该因子负责圆锥形细胞，来自具有不同花形态的三个物种，代表两种授粉综合症。通过 PCR 克隆基因并进行系统发育分析。通过定量PCR和原位杂交进行表达分析，然后进行转基因烟草中的功能研究。克隆的基因编码与金鱼草AmMYBML2和矮牵牛PhMYB1密切相关的R2R3 MYB蛋白。原位杂交的空间表达与圆锥形细胞的区域重叠。烟草中的过度表达会诱导心皮表皮细胞生长，并显着增加花瓣圆锥形细胞的高度。我们已经描述了核心真双子叶植物之外的 AmMIXTA-like2 的第一个直系同源物，可能是 MIXTA/MIXTA-like1 重复的祖先。表皮细胞伸长中的保守作用导致圆锥形细胞的产生，这是花瓣状的微形态标记。在唐松草的风授粉进化之后，这种吸引昆虫传粉媒介的适应性显然消失了。New Phytological (2009) 183:718-728doi:10.1111/j.1469-8137.2009.02945.x。
P>Here, we investigated the genetic underpinnings of pollination-related floral phenotypes in Thalictrum, a ranunculid with apetalous flowers. The variable presence of petaloid features in other floral organs correlates with distinct adaptations to insect vs. wind pollination. Conical cells are present in sepals or stamens of insect-pollinated species, and in stigmas. We characterized a Thalictrum ortholog of the Antirrhinum majus transcription factor MIXTA-like2, responsible for conical cells, from three species with distinct floral morphologies, representing two pollination syndromes.Genes were cloned by PCR and analysed phylogenetically. Expression analyses were conducted by quantitative PCR and in situ hybridization, followed by functional studies in transgenic tobacco.The cloned genes encode R2R3 MYB proteins closely related to Antirrhinum AmMYBML2 and Petunia hybrida PhMYB1. Spatial expression by in situ hybridization overlaps areas of conical cells. Overexpression in tobacco induces cell outgrowths in carpel epidermis and significantly increases the height of petal conical cells.We have described the first orthologs of AmMIXTA-like2 outside the core eudicots, likely ancestral to the MIXTA/MIXTA-like1 duplication. The conserved role in epidermal cell elongation results in conical cells, micromorphological markers for petaloidy. This adaptation to attract insect pollinators was apparently lost after the evolution of wind pollination in Thalictrum.New Phytologist (2009) 183: 718-728doi: 10.1111/j.1469-8137.2009.02945.x.