The model plant Medicago truncatula exhibits biparental plastid inheritance
The model plant Medicago truncatula exhibits biparental plastid inheritance
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DOI：
10.1093/pcp/pcm170
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发表时间：
2008-01-01
影响因子：
4.9
通讯作者：
Sakamoto, Wataru
中科院分区：
文献类型：
--
作者：
Matsushima, Ryo;Hu, Yingchun;Sakamoto, Wataru
起源于蓝藻内共生的质体DNA(PtDNA)含有自己的质体DNA，表现出独特的遗传模式。大约80%的被子植物表现出母系遗传，其余的表现出ptDNA的双亲遗传。在这里，我们研究了模式豆科植物紫花苜蓿的ptDNA遗传。用DNA特异的荧光染料对成熟花粉进行细胞学分析表明，元宝菊是为数不多的可能显示ptDNA双亲遗传的模式植物之一。我们进一步用电子显微镜检查了花粉，发现生殖细胞(精子细胞的母亲)确实有许多含有DNA的质体。为了从遗传学上证实双亲遗传，我们用两个生态型(杰马龙A17和A20)杂交，并用聚合酶链式反应(PCR)辅助的多态方法研究了ptDNA的传递方式。与细胞学观察一致的是，大多数F-1植株都含有来自双亲的ptDNA。有趣的是，F-1植株的子叶倾向于保留双亲的ptDNA群体，而较晚的出苗叶片倾向于与亲本中的任何一种叶绿体基因型单亲。双亲传递在F-2群体中很明显，在F-2群体中，所有的植株都表现出同质性，要么是父本的，要么是母本的。综上所述，这些数据表明，元宝草是ptDNA传递的双亲，因此可以成为研究被子植物叶绿体遗传学的一个很好的模型。
The plastid, which originated from the endosymbiosis of a cyanobacterium, contains its own plastid DNA (ptDNA) that exhibits a unique mode of inheritance. Approximately 80 of angiosperms show maternal inheritance, whereas the remainder exhibit biparental inheritance of ptDNA. Here we studied ptDNA inheritance in the model legume, Medicago truncatula. Cytological analysis of mature pollen with DNA-specific fluorescent dyes suggested that M. truncatula is one of the few model plants potentially showing biparental inheritance of ptDNA. We further examined pollen by electron microscopy and revealed that the generative cell (a mother of sperm cells) indeed has many DNA-containing plastids. To confirm biparental inheritance genetically, we crossed two ecotypes (Jemalong A17 and A20), and the transmission mode of ptDNA was investigated by a PCR-assisted polymorphism. Consistent with the cytological observations, the majority of F-1 plants possessed ptDNAs from both parents. Interestingly, cotyledons of F-1 plants tended to retain a biparental ptDNA population, while later emergent leaves tended to be uniparental with either one of the parental plastid genotypes. Biparental transmission was obvious in the F-2 population, in which all plants showed homoplasmy with either a paternal or a maternal plastid genotype. Collectively, these data demonstrated that M. truncatula is biparental for ptDNA transmission and thus can be an excellent model to study plastid genetics in angiosperms.