Alternative splicing of the AGAMOUS orthologous gene in double flower of Magnolia stellata (Magnoliaceae).
Alternative splicing of the AGAMOUS orthologous gene in double flower of Magnolia stellata (Magnoliaceae).
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DOI：
10.1016/j.plantsci.2015.10.017
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发表时间：
2015-12
期刊：
影响因子：
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通讯作者：
Bo Zhang;Zhixiong Liu;Jiang Ma;Yi Song;Faju Chen
中科院分区：
文献类型：
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作者：
Bo Zhang;Zhixiong Liu;Jiang Ma;Yi Song;Faju Chen
木兰是木本观赏灌木，花瓣状花被比木兰科相关植物多。最近的研究表明，AnAGAMOUS(AG)同源基因的表达变化可能导致重瓣花的花瓣数量增加。我们分离到了编码单个AG同源基因MastAG，mastag_2和mastag_3不同亚型的三个转录本。星形。序列比对和Southern杂交分析表明，MastAGINM为单拷贝基因。以及mastag_2和mastag_3是MastAG的异常剪接异构体。MastAG中144个碱基的外显子跳过导致截短的mastag_2蛋白缺少完整的I结构域和K1亚区的18个氨基酸，而MastAG的165个碱基的外显子跳过导致截短的mastag_3蛋白缺少K3亚域的6个氨基酸和完整的C末端区域。表达分析表明，三种选择性剪接(AS)亚型仅在发育中的雄蕊和心皮中表达。功能分析表明，MastAG可以模拟内源AG来确定心皮的特性，但不能调控拟南芥的雄蕊发育。此外，以mastag_2和mastag_3为代表的关键域或亚域缺失导致C-功能丧失。但是，异位表达的mastag_2在拟南芥中产生了花，花被片转化为心形器官，但没有花瓣和雄蕊，而在拟南芥中异位表达的mastag_3可以模仿该突变体的花表型，并产生双花，雄蕊同源转化为花瓣，心皮转化为另一朵花。我们的结果还表明，mastag_3在生物技术工程中创造商业观赏品种的多花瓣表型具有一定的潜力。
Magnolia stellatais a woody ornamental shrub with more petaloid tepals than related plants from family Magnoliaceae. Recent studies revealed that expression changes in anAGAMOUS(AG) orthologous gene could resulted in double flowers with increased numbers of petals. We isolated three transcripts encoding different isoforms of a singleAGorthologous gene,MastAG,mastag_2andmastag_3, fromM. stellata. Sequence alignments and Southern blot analyses suggested thatMastAGwas a single-copy gene inM. stellatagenomes, and thatmastag_2andmastag_3were abnormally spliced isoforms ofMastAG. An 144 bp exon skipping inMastAGresults in the truncated mastag_2 protein lacking the completely I domain and 18 aa of the K1 subdomain, whereas an 165 bp exon skipping ofMastAGproduces a truncated mastag_3 protein lacking 6 aa of the K3 subdomain and the completely C terminal region. Expression analyses showed that three alternative splicing (AS) isoforms expressed only in developing stamens and carpels. Functional analyses revealed thatMastAGcould mimic the endogenousAGto specify carpel identity, but failed to regulate stamen development in anArabidopsis ag-1mutant. Moreover, the key domain or subdomain deletions represented by mastag_2 and mastag_3 resulted in loss of C-function. However, ectopic expression ofmastag_2inArabidopsisproduced flowers with sepals converted into carpeloid organs, but without petals and stamens, whereas ectopic expression ofmastag_3inArabidopsiscould mimic the flower phenotype of theagmutant and produced double flowers with homeotic transformation of stamens into petals and carpels into anotheragflower. Our results also suggest thatmastag_3holds some potential for biotechnical engineering to create multi-petal phenotypes in commercial ornamental cultivars.