Ge S, Sang T, Lu B R, Hong D Y
Laboratory of Systematic Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Proc Natl Acad Sci U S A. 1999 Dec 7;96(25):14400-5. doi: 10.1073/pnas.96.25.14400.
The rice genus, Oryza, which comprises 23 species and 9 recognized genome types, represents an enormous gene pool for genetic improvement of rice cultivars. Clarification of phylogenetic relationships of rice genomes is critical for effective utilization of the wild rice germ plasm. By generating and comparing two nuclear gene (Adh1 and Adh2) trees and a chloroplast gene (matK) tree of all rice species, phylogenetic relationships among the rice genomes were inferred. Origins of the allotetraploid species, which constitute more than one-third of rice species diversity, were reconstructed based on the Adh gene phylogenies. Genome types of the maternal parents of allotetraploid species were determined based on the matK gene tree. The phylogenetic reconstruction largely supports the previous recognition of rice genomes. It further revealed that the EE genome species is most closely related to the DD genome progenitor that gave rise to the CCDD genome. Three species of the CCDD genome may have originated through a single hybridization event, and their maternal parent had the CC genome. The BBCC genome species had different origins, and their maternal parents had either a BB or CC genome. An additional genome type, HHKK, was recognized for Oryza schlechteri and Porteresia coarctata, suggesting that P. coarctata is an Oryza species. The AA genome lineage, which contains cultivated rice, is a recently diverged and rapidly radiated lineage within the rice genus.
稻属(Oryza)包含23个物种和9种公认的基因组类型,是水稻品种遗传改良的巨大基因库。阐明水稻基因组的系统发育关系对于有效利用野生稻种质至关重要。通过构建并比较所有水稻物种的两个核基因(Adh1和Adh2)树和一个叶绿体基因(matK)树,推断出水稻基因组之间的系统发育关系。基于Adh基因系统发育重建了占水稻物种多样性三分之一以上的异源四倍体物种的起源。基于matK基因树确定了异源四倍体物种母本的基因组类型。系统发育重建在很大程度上支持了先前对水稻基因组的认识。它进一步揭示,EE基因组物种与产生CCDD基因组的DD基因组祖先关系最为密切。CCDD基因组的三个物种可能起源于一次单一的杂交事件,它们的母本具有CC基因组。BBCC基因组物种有不同的起源,它们的母本具有BB或CC基因组。在糙叶稻(Oryza schlechteri)和紧穗野生稻(Porteresia coarctata)中识别出了一种额外的基因组类型HHKK, 这表明紧穗野生稻是一种稻属物种。包含栽培稻的AA基因组谱系是稻属内一个最近分化且快速辐射的谱系。