Hori Tada-aki, Hayashi Akiko, Sasanuma Tsuneo, Kurita Siro
Transcriptome Profiling Group, National Institute of Radiological Sciences, Chiba, Japan.
Genes Genet Syst. 2006 Aug;81(4):243-53. doi: 10.1266/ggs.81.243.
The genus Lycoris of Amaryllidaceae comprises approximately 20 species that are distributed only in the moist warm temperate woodlands of eastern Asia. The objectives of this study were: (1) to clarify the phylogeny of the Lycoris species by using the definitive DNA sequencing method and (2) to examine the possible maternal donor of the hybrid origin Lycoris species and the Japanese triploid strains of Lycoris radiata var. radiata. The nucleotide sequence of the maturase K (matK) gene and the noncoding intergenic spacer (IGS) between the atpB and rbcL genes in the chloroplast genome were determined in a total of 27 strains of 11 species of the genus Lycoris. Variation among taxa was mainly due to nucleotide substitution, although deletions and an insertion were found in the IGS. For two chloroplast regions, the phylogenetic trees showed essentially similar topology, indicating the existence of four clades, I, II, III, and IV. For all the species except L. radiata, intraspecific variation was smaller than interspecific variation. For L. radiata, triploid strains were divided into clades I and II, and diploid strains were divided into clades I and IV. This implies that the diploid species of L. radiata var. pumila is a probable ancestral species. The clustering indicated that the chloroplast genome has not evolved in parallel with the karyotype in genus Lycoris. Regarding the hybrid origin species, the maternal parents of L. squamigara, L. albiflora and L. rosea were revealed to be L. longituba, L. radiata and L. radiata var pumila, respectively. We also suggest that a diploid strain of L. radiata var. pumila in clade I might be a candidate of the maternal donor of the Japanese triploid strains. A possible model of the maternal donor of Lycoris species is proposed.
石蒜科石蒜属包含约20个物种，仅分布于东亚温暖湿润的温带林地。本研究的目的是：（1）通过使用确定性DNA测序方法阐明石蒜属物种的系统发育，以及（2）研究杂交起源的石蒜属物种和日本石蒜辐射变种的三倍体菌株的可能母本供体。对石蒜属11个物种的27个菌株测定了叶绿体基因组中成熟酶K（matK）基因的核苷酸序列以及atpB和rbcL基因之间的非编码基因间隔区（IGS）。尽管在IGS中发现了缺失和一个插入，但类群间的变异主要是由于核苷酸替换。对于两个叶绿体区域，系统发育树显示出基本相似的拓扑结构，表明存在四个分支，即I、II、III和IV。除石蒜外，所有物种的种内变异均小于种间变异。对于石蒜，三倍体菌株分为分支I和II，二倍体菌株分为分支I和IV。这意味着石蒜辐射变种矮小的二倍体物种可能是祖先物种。聚类分析表明，石蒜属的叶绿体基因组并未与核型平行进化。关于杂交起源的物种，已揭示出换锦花、白花石蒜和玫瑰石蒜的母本分别为长筒石蒜、石蒜和石蒜辐射变种矮小。我们还认为，分支I中的石蒜辐射变种矮小的二倍体菌株可能是日本三倍体菌株母本供体的候选者。提出了石蒜属物种母本供体的一种可能模型。
