Genetic Redundancy in Soybean Photoresponses Associated With Duplication of the Phytochrome A Gene
Genetic Redundancy in Soybean Photoresponses Associated With Duplication of the Phytochrome A Gene
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DOI：
10.1534/genetics.108.092742
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发表时间：
2008-10-01
期刊：
影响因子：
3.3
通讯作者：
Abe, Jun
中科院分区：
文献类型：
--
作者：
Liu, Baohui;Kanazawa, Akira;Abe, Jun
基因和基因组复制是植物进化新颖性的基础。大豆被认为是一个具有复杂基因组的古老多倍体物种。我们在大豆基因组中发现了光敏色素A基因(PhyA)的多个同源基因，并测定了两个同源基因Gmphy A1和Gmphy A2的DNA序列。对在光周期不敏感基因E4上带有隐性等位基因的品系Gmphy A2基因的分析表明，在该基因的第一外显子中插入了一个Ty1/CopiA类反转录转座子，导致了该基因的功能障碍。图谱研究表明Gmphy A2是由E4编码的。Gmphy A1基因被定位到0连锁群的一个区域，该区域与连锁群1中含有E4的区域同源。e4等位基因纯合的植株在连续的远红光下会黄化，但部分脱黄化，表明该突变本身并不会导致PhyA功能的完全丧失。遗传冗余表明，PhyA基因的复制副本的存在导致了光周期不敏感的产生，同时防止了突变的有害影响。因此，这种现象提供了基因复制和植物对环境的适应性反应之间的联系。
Gene and genome duplications underlie the origins of evolutionary novelty in plants. Soybean, Glycine max, is considered to be a paleopolyploid species with a complex genome. We found multiple homologs of the phytochrome A gene (phyA) in the soybean genome and determined the DNA sequences of two paralogs designated GmphyA1 and GmphyA2. Analysis of the GmphyA2 gene from the lines carrying a recessive allele at a photoperiod insensitivity locus, E4, revealed that a Ty1/copia-like retrotransposon was inserted in exon 1 of the gene, which resulted in dysfunction of the gene. Mapping studies suggested that GmphyA2 is encoded by E4. The GmphyA1 gene was mapped to a region of linkage group 0, which is homeologous to the region harboring E4 in linkage group I. Plants homozygous for the e4 allele were etiolated under continuous far red light, but the de-etiolation Occurred partially, indicating that the mutation alone did not cause a complete loss of phyA function. The genetic redundancy suggests that the presence of duplicated copies of phyA genes accounts for the generation of photoperiod insensitivity, while protecting against the deleterious effects Of Mutation. Thus, this phenomenon provides a link between gene duplication and establishment of an adaptive response of plants to environments.