Exploiting the Arabidopsis thaliana relative Cardamine hirsuta for understanding dissected leaf development

生物学中的一个关键问题是理解不同的有机体是如何形成不同的形式的。在植物中，这种形式的变化在公园散步时看到的许多不同的叶子形状中都很明显。叶片也是值得研究的，因为它们在食物链中扮演着关键角色，是陆地植物的主要光合器官，因此在陆地生态系统中负责固定二氧化碳。出于这些原因，了解树叶形态的多样性是如何产生的，这对科学家来说是相当感兴趣的。为了研究这个问题，我们用毛茸茸的苦菜(Cardamine Hirsuta)来研究这个问题，这种植物的叶子完全细分为更小的小叶。小叶的存在使这种植物与它的近亲拟南芥(Arabiopsis Thaliana)非常不同，后者有完整的、不分裂的叶子。我们已经知道了很多关于水芹是如何产生整个叶子形状的，因为它很容易种植和做实验。毛茸茸的苦菜在实验室里也很容易处理，所以我们用它来了解传单是如何产生的。我们最近已经证明，生长素的调节传递也是在毛茸茸的苦菜叶片中形成小叶所必需的。生长素是一种已知的小激素，可以在水芹和其他植物的生长顶端触发叶片的形成。这是一个令人兴奋的发现，因为它表明，指示细胞变成叶子的相同机制也可能在发育后期被用来塑造不同植物区分的不同叶子形状。我们现在想知道，毛茸茸的苦菜的基因构成的哪些方面允许这种物种产生对生长素有反应的小叶，而不是水芹。

A key problem in biology is to understand how different organisms come to have different forms. In plants this variation in form is obvious in the many different leaf shapes one sees during a walk in the park. Leaves are also interesting to study because they play a key role in the food chain being the main photosynthetic organs of land plants and thus responsible for CO2 fixation in terrestrial ecosystems. For these reasons, understanding how diversity in leaf form is generated is of considerable interest to scientists. To study this problem we work with hairy bittercress (Cardamine hirsuta), which is a plant that has leaves fully subdivided into smaller leaflets. The presence of leaflets makes this plant very different to its close relative thale cress (Arabidopsis thaliana), which has entire, undivided leaves. We already know a lot about how an entire leaf shape is produced in thale cress because it is easy to grow and do experiments with. Hairy bittercress is also very easy to work with in the lab, so we use it to understand how leaflets are produced. We have recently shown that regulated delivery of auxin which is a small hormone known to trigger leaf formation at the growing tips of the thale cress and other plants, is also required for leaflets to form in hairy bittercress leaves. This is an exciting finding because it suggests that the same mechanism that instructs cells to become leaves may also be used later in development to sculpt the various leaf shapes that distinguish different plants. We now want to understand what aspects of the genetic make up of the hairy bittercress allow auxin responsive leaflet production in this species but not thale cress.