PDF(Pubmed)
Abstract：
The development of floral organs, crucial for the establishment of floral symmetry and morphology in higher plants, is regulated by MADS-box genes. In sunflower, the capitulum is comprised of ray and disc florets with various floral organs. In the sunflower long petal mutant (lpm), the abnormal disc (ray-like) floret possesses prolongated petals and degenerated stamens, resulting in a transformation from zygomorphic to actinomorphic symmetry. In this study, we investigated the effect of MADS-box genes on floral organs, particularly on petals, using WT and lpm plants as materials. Based on our RNA-seq data, 29 MADS-box candidate genes were identified, and their roles on floral organ development, especially in petals, were explored, by analyzing the expression levels in various tissues in WT and lpm plants through RNA-sequencing and qPCR. The results suggested that HaMADS3, HaMADS7, and HaMADS8 could regulate petal development in sunflower. High levels of HaMADS3 that relieved the inhibition of cell proliferation, together with low levels of HaMADS7 and HaMADS8, promoted petal prolongation and maintained the morphology of ray florets. In contrast, low levels of HaMADS3 and high levels of HaMADS7 and HaMADS8 repressed petal extension and maintained the morphology of disc florets. Their coordination may contribute to the differentiation of disc and ray florets in sunflower and maintain the balance between attracting pollinators and producing offspring. Meanwhile, Pearson correlation analysis between petal length and expression levels of MADS-box genes further indicated their involvement in petal prolongation. Additionally, the analysis of cis-acting elements indicated that these three MADS-box genes may regulate petal development and floral symmetry establishment by regulating the expression activity of HaCYC2c. Our findings can provide some new understanding of the molecular regulatory network of petal development and floral morphology formation, as well as the differentiation of disc and ray florets in sunflower.
摘要：
花器官的发育，对于在高等植物中建立花的对称性和形态至关重要，受MADS-box基因调控。在向日葵，头状花序由射线和圆盘小花组成，具有各种花器官。在向日葵长花瓣突变体（lpm）中，异常的圆盘状（射线状）小花具有延长的花瓣和退化的雄蕊，导致从同构对称到辐射对称的转变。在这项研究中,我们研究了MADS-box基因对花器官的影响，特别是在花瓣上，使用WT和LPM植物作为材料。根据我们的RNA-seq数据,确定了29个MADS-box候选基因，以及它们在花器官发育中的作用，尤其是花瓣,被探索，通过RNA测序和qPCR分析WT和lpm植物中各种组织的表达水平。结果表明，HaMADS3，HaMADS7和HaMADS8可以调节向日葵花瓣的发育。高水平的HaMADS3缓解了对细胞增殖的抑制，与低水平的HaMADS7和HaMADS8一起，促进了花瓣的延长并保持了射线小花的形态。相比之下,低水平的HaMADS3和高水平的HaMADS7和HaMADS8抑制了花瓣的延伸并维持了椎间盘小花的形态。它们的协调可能有助于向日葵中圆盘和射线小花的分化，并保持吸引传粉者和产生后代之间的平衡。同时,花瓣长度和MADS-box基因表达水平之间的Pearson相关性分析进一步表明它们参与花瓣延长。此外,对顺式作用元件的分析表明，这三个MADS-box基因可能通过调节HaCYC2c的表达活性来调节花瓣发育和花对称性的建立。我们的发现可以为花瓣发育和花形态形成的分子调控网络提供一些新的认识。以及向日葵中圆盘和光线小花的分化。
