Local maternal control of seed size by KLUH/CYP78A5-dependent growth signaling
Local maternal control of seed size by KLUH/CYP78A5-dependent growth signaling
复制标题
DOI：
10.1073/pnas.0907024106
复制
发表时间：
2009-11-24
影响因子：
11.1
通讯作者：
Lenhard, Michael
中科院分区：
文献类型：
--
作者：
Adamski, Nikolai M.;Anastasiou, Elena;Lenhard, Michael
植物种子的发育涉及胚、胚乳和母体组织的协调生长。已经鉴定出几个基因通过母性作用影响种子大小，如生长素反应因子2、APETALA 2和DA 1。然而，鉴于这些基因对种子大小缺乏功能获得效应，尚不清楚它们的活性水平是否在WT植物中是限制性的，以及它们是否因此可以用于在发育或进化中调节种子大小。此外，改变的种子大小是否反映了局部基因活性或整体生理变化尚不清楚。在这里，我们证明了细胞色素P450 KLUH（KLU）调节种子大小。KLU在花发育中局部作用以促进种子生长，并且其活性水平限制WT中的种子生长。KLU在发育胚珠的内珠被中表达，在那里它非细胞自主地刺激细胞增殖，从而决定种皮和种子的生长潜力。KLU诱导的种子大小的增加导致更大的幼苗和更高的种子相对含油量。遗传分析表明，KLU的行为独立于其他测试的母体因素，影响珠被细胞增殖。因此，KLU依赖性生长因子信号传导的水平决定了胚珠和种子的大小，这表明该途径是作物改良的目标。
Seed development in plants involves the coordinated growth of the embryo, endosperm, and maternal tissue. Several genes have been identified that influence seed size by acting maternally, such as AUXIN RESPONSE FACTOR2, APETALA2, and DA1. However, given the lack of gain-of-function effects of these genes on seed size, it is unclear whether their activity levels are limiting in WT plants and whether they could thus be used to regulate seed size in development or evolution. Also, whether the altered seed sizes reflect local gene activity or global physiological changes is unknown. Here, we demonstrate that the cytochrome P450 KLUH (KLU) regulates seed size. KLU acts locally in developing flowers to promote seed growth, and its activity level is limiting for seed growth in WT. KLU is expressed in the inner integument of developing ovules, where it non-cell autonomously stimulates cell proliferation, thus determining the growth potential of the seed coat and seed. A KLU-induced increase in seed size leads to larger seedlings and higher relative oil content of the seeds. Genetic analyses indicate that KLU acts independently of other tested maternal factors that influence integument cell proliferation. Thus, the level of KLU-dependent growth factor signaling determines size in ovules and seeds, suggesting this pathway as a target for crop improvement.