The expression and phylogenetic analysis of four AP3-like paralogs in the stamens, carpels, and single-whorl perianth of the paleoherb Asarum caudigerum
The expression and phylogenetic analysis of four AP3-like paralogs in the stamens, carpels, and single-whorl perianth of the paleoherb Asarum caudigerum
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古草本植物细辛雄蕊、心皮和单轮花被中四种 AP3 样旁系同源基因的表达和系统发育分析
DOI：
10.1007/s11033-013-2564-9
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发表时间：
2013-08-01
影响因子：
2.8
通讯作者：
Li，Cheng-Yun
中科院分区：
文献类型：
--
作者：
Zhao，Yin-He;Larson-Rabin，Zachary;Li，Cheng-Yun
古草本植物细辛（Aristolochiaceae）在被子植物花的起源和演化研究中占有重要地位。本研究从A.通过cDNA末端快速扩增（RACE）技术，序列比较和系统发育分析表明，它们与AP 3亚家族基因具有高度同源性，这些基因此前已被证明参与真双子叶植物花瓣和雄蕊的发育。逆转录定量PCR（RT-qPCR）和原位杂交分析表明，AcAP 3-A主要在第二轮（雄蕊）中表达，AcAP 3-B主要在第1轮和第3轮（花被和心皮）中表达。与真双子叶植物AP 3同源物相比，提前终止密码子是由AcAP 3-C的K1结构域的插入和AcAP 3-D的第7外显子的缺失引起的。序列分析表明，A. caudigerum AP 3基因在花被、雄蕊和心皮发育过程中经历了基因复制和亚功能化，表达模式发生了变化。基于比较基因组学和系统发育分析，我们得出结论，亚功能化可能有助于两个功能性AP 3旁系同源物的持续存在，另外两个拷贝可能已经成为假基因，这些AP 3复制和亚功能化事件可能有助于A.尾精
The paleoherb species Asarum caudigerum (Aristolochiaceae) is important for research into the origin and evolution of angiosperm flowers due to its basal position in the angiosperm phylogeny. In this study, four MADS-box-containing transcripts were isolated from A. caudigerum by rapid amplification of cDNA ends (RACE). Sequence comparisons and phylogenetic analyses indicated that they possess high homology to AP3 subfamily genes, which have been shown previously to be involved in petal and stamen development in eudicots. Reverse-transcription quantitative PCR (RT-qPCR) and in situ hybridization analyses showed AcAP3-A expression mainly in the second whorl (stamens) and AcAP3-B expression in whorls 1 and 3 (perianth and carpels). Compared with eudicot AP3 homologs, premature translation termination codons were caused by an insertion in the K1 domain of AcAP3-C, and by a deletion in the 7th exon of AcAP3-D. Sequence analyses suggested that the A. caudigerum AP3 lineage had undergone gene duplication and subfunctionalization, diverging in expression patterns during perianth, stamen, and carpel development. Based on comparative genomic and phylogenetic analyses, we concluded that subfunctionalization has likely contributed to the persistence of two functional AP3 paralogs, that two other copies may have become pseudogenes, and that these AP3 duplication and subfunctionalization events may have contributed to the evolution of the unusual floral morphology of A. caudigerum.