欧洲千里光SvAPETALA1基因的克隆及功能分析

  目的  花器官发育是影响花观赏价值的重要因素，AP1类基因调控植物花器官的形成。研究菊科Asteraceae欧洲千里光Senecio vulgaris的SvAP1基因在花器官形成中的重要作用，旨在探究菊科复杂花序结构产生的调控机制。  方法  以欧洲千里光为材料克隆获得了SvAP1基因，通过多序列比对、构建系统进化树、实时荧光定量PCR (qRT-PCR)反应、构建超表达载体、组织学染色观察等方法与技术，对SvAP1基因进行功能预测与分析。  结果  SvAP1基因开放阅读框长度为705 bp，编码234个氨基酸。多序列比对与系统进化分析显示:SvAP1基因属于MADS-box基因AP1类亚家族，C末端具有paleoAP1保守基序(motif)。欧洲千里光组织特异性表达分析表明:SvAP1基因在营养器官和花序中都有表达。转基因龙葵Solanum nigrum的形态学观察和石蜡切片技术分析显示:与野生型龙葵相比，转基因龙葵雌蕊发育异常，表现为子房膨大且雌蕊状组织增多。  结论  欧洲千里光SvAP1基因在龙葵中的超表达影响雌蕊发育，与ABC模型中A类基因超表达对植物花器官发育造成的影响存在差异，即转基因龙葵雄蕊无明显变化且雌蕊未转变为萼片状或叶片状器官。这可能与欧洲千里光花器官调节机制和花序结构的复杂性有关。由此可知，欧洲千里光SvAP1基因可能作为花器官特征基因在花器官形成中具有重要作用。图6表1参35

Cloning and functional analysis of SvAPETALA1 in Senecio vulgaris

  Objective  Floral organ development is an important factor affecting the ornamental value of flowers, and APETALA1 (AP1) genes regulate the formation of floral organs. This study aims to explore the important role of SvAP1 gene of Senecio vulgaris (Asteraceae) in floral organ formation, so as to reveal the regulatory mechanism of the complex inflorescence structure in Asteraceae.   Method  SvAP1 gene was cloned from S. vulgaris. The function of SvAP1 gene was predicted and analyzed by multiple sequence alignment, phylogenetic tree construction, qRT-PCR, overexpression vector construction, and histological staining observation.  Result  The open reading frame (ORF) of SvAP1 gene was 705 bp in length, and encoded 234 amino acids. Multiple sequence alignment and phylogenetic analysis showed that SvAP1 gene belonged to AP1 subfamily of MADS-box gene, and the C-terminus had a conserved motif of paleoAP1. Tissue specific expression analysis of S. vulgaris showed that SvAP1 gene was expressed in both vegetative organs and inflorescences. Morphological observation and paraffin section analysis of transgenic Solanum nigrum showed that compared with wild S. nigrum, the pistil development of transgenic S. nigrum was abnormal, which was characterized by enlarged ovary and increased pistil-like tissue.  Conclusion  The overexpression of SvAP1 gene in S. nigrum affects the pistil development, which is different from the effect of over expression of class A gene in ABC model on floral organ development, that is, the stamens of transgenic S. nigrum have no obvious changes and the pistils aren’t transformed into sepal or leaf-like organs, which may be related to the complexity of the floral organ regulation mechanism and the inflorescence structure of S. vulgaris. In conclusion, SvAP1 gene may play an important role in floral organ formation as a characteristic gene of floral organ. Ch, 6 fig. 1 tab. 35 ref.]