Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829, Köln, Germany.
Plant Sciences Department, University of Oxford, South Parks Rd, Oxford, OX1 3RB, UK.
New Phytol. 2017 Oct;216(2):549-561. doi: 10.1111/nph.14419. Epub 2017 Jan 18.
A conserved genetic toolkit underlies the development of diverse floral forms among angiosperms. However, the degree of conservation vs divergence in the configuration of these gene regulatory networks is less clear. We addressed this question in a parallel genetic study between the closely related species Arabidopsis thaliana and Cardamine hirsuta. We identified leafy (lfy) and apetala1 (ap1) alleles in a mutant screen for floral regulators in C. hirsuta. C. hirsuta lfy mutants showed a complete homeotic conversion of flowers to leafy shoots, mimicking lfy ap1 double mutants in A. thaliana. Through genetic and molecular experiments, we showed that AP1 activation is fully dependent on LFY in C. hirsuta, by contrast to A. thaliana. Additionally, we found that LFY influences heteroblasty in C. hirsuta, such that loss or gain of LFY function affects its progression. Overexpression of UNUSUAL FLORAL ORGANS also alters C. hirsuta leaf shape in an LFY-dependent manner. We found that LFY and AP1 are conserved floral regulators that act nonredundantly in C. hirsuta, such that LFY has more obvious roles in floral and leaf development in C. hirsuta than in A. thaliana.
一套保守的遗传工具为被子植物多样化的花部形态发育奠定了基础。然而，这些基因调控网络的结构在保守性与分化程度上的情况并不明晰。我们通过对近缘物种拟南芥和长角车前之间的平行遗传学研究来解答这个问题。我们在长角车前的花发育调控因子突变体筛选中鉴定到了叶状（lfy）和无花瓣 1（ap1）等位基因。长角车前的 lfy 突变体表现出花完全同源转化为叶状茎，与拟南芥的 lfy ap1 双突变体类似。通过遗传和分子实验，我们发现 AP1 的激活在长角车前完全依赖于 LFY，而在拟南芥中并非如此。此外，我们发现 LFY 影响长角车前的异型叶性，其功能的缺失或获得会影响异型叶性的进程。过量表达 UNUSUAL FLORAL ORGANS 也以 LFY 依赖的方式改变长角车前的叶形。我们发现 LFY 和 AP1 是保守的花发育调控因子，在长角车前中发挥非冗余作用，因此 LFY 在长角车前的花和叶发育中比在拟南芥中具有更明显的作用。
