Qiao Zhongquan, Deng Fuyuan, Zeng Huijie, Li Xuelu, Lu Liushu, Lei Yuxing, Li Lu, Chen Yi, Chen Jianjun
Hunan Provincial Key Laboratory of Forest Clonal Breeding, Hunan Academy of Forestry, Changsha 410004, China.
College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China.
Plants (Basel). 2024 Mar 1;13(5):709. doi: 10.3390/plants13050709.
MADS-box is a key transcription factor regulating the transition to flowering and flower development. 'Xiang Yun' is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of 'Xiang Yun', 82 MADS-box genes were identified from the genome of . The physicochemical properties of these genes were examined using bioinformatics methods, and their expression as well as endogenous hormone levels at various stages of flower development were analyzed. The results showed that genes were primarily classified into two types: type I and type II, with the majority being type II that contained an abundance of cis-acting elements in their promoters. By screening nine core proteins by predicted protein interactions and performing qRT-PCR analysis as well as in combination with transcriptome data, we found that the expression levels of most genes involved in flower development were significantly lower in 'Xiang Yun' than in the wild type 'Hong Ye'. Hormonal analysis indicated that 'Xiang Yun' had higher levels of iP, IPR, TZR, and zeatin during its early stages of flower development than 'Hong Ye', whereas the MeJA content was substantially lower at the late stage of flower development of 'Hong Ye'. Finally, correlation analysis showed that JA, IAA, SA, and TZR were positively correlated with the expression levels of most type II genes. Based on these analyses, a working model for the non-fruiting 'Xiang Yun' was proposed. During the course of flower development, plant hormone response pathways may affect the expression of MADS genes, resulting in their low expression in flower development, which led to the abnormal development of the stamen and embryo sac and ultimately affected the fruiting process of 'Xiang Yun'.
MADS盒是调控开花转变和花发育的关键转录因子。‘祥云’是紫薇的一个新栽培品种，其特点是不结果。为了研究‘祥云’不结果特性的分子机制，从其基因组中鉴定出82个MADS盒基因。利用生物信息学方法检测了这些基因的理化性质，并分析了它们在花发育各个阶段的表达以及内源激素水平。结果表明，这些基因主要分为两类：I型和II型，其中大多数为II型，其启动子中含有丰富的顺式作用元件。通过预测蛋白质相互作用筛选出9个核心蛋白，进行qRT-PCR分析并结合转录组数据，我们发现参与花发育的大多数基因在‘祥云’中的表达水平显著低于野生型‘红叶’。激素分析表明，‘祥云’在花发育早期的iP、IPR、TZR和玉米素水平高于‘红叶’，而在‘红叶’花发育后期茉莉酸甲酯含量则显著较低。最后，相关性分析表明，茉莉酸、生长素、水杨酸和TZR与大多数II型基因的表达水平呈正相关。基于这些分析，提出了‘祥云’不结果的工作模型。在花发育过程中，植物激素反应途径可能影响MADS基因的表达，导致其在花发育中表达量低，进而导致雄蕊和胚囊发育异常，最终影响‘祥云’的结果过程。
