谷子近缘野生种的亲缘关系及其利用研究

谷子在约1万年前由青狗尾草驯化而来,我国是谷子的起源中心。谷子所属的狗尾草属在全世界约有125个种,其中中国有15个种,从二倍体到八倍体均有。目前利用染色体原位杂交技术鉴定出狗尾草属6个基因组,利用分子标记分析发现狗尾草属是多起源的,与其多样性的基因组一致。系统演化分析发现,青狗尾草和谷子亲缘关系最近,其次是法式狗尾草和轮生狗尾草;基因组比较分析发现, S. adhaerans的B基因组和S. grisebachii的C基因组与谷子和青狗尾草的A基因具有相对近的亲缘关系,而其他基因组和谷子亲缘较远。在野生资源的利用方面,谷子育种工作者已成功将近缘野生种自然发生的抗除草剂基因转育到谷子中,培育成功了可化学除草的新品种并在生产上利用。本文对谷子野生种的分类、基因组构成、系统进化关系和遗传育种的研究进展进行了综述,重点讨论了谷子近缘野生种在谷子起源与驯化、遗传育种中起到的作用,并对谷子近缘野生种在谷子驯化及育种中的进一步利用做了展望。

Phylogeny of wild Setaria species and their utilization in foxtail millet breeding

Foxtail millet(Setaria italica) was domesticated from the wild ancestor,green foxtail(S.viridis),about ten thousand years ago in China.Foxtail millet belongs to Setaria genus,which includes about 125 species of panicoid grasses worldwide,and 15 species of them in China varied from diploid to octoploid.Currently,six genomes in the Setaria genus have been identified by GISH(genomic in situ hybridization).Molecular phylogenetic analyses show that the Setaria genus is polyphyletic,in line with the characteristic of diversified genomes.Phylogeny of Setaria genus reveal that foxtail millet is most closely related with green foxtail,and then S.fabrei and S.verticillata,and that A genome of S.italica/S.viridis appears to be closer to B genome of S.adhaeran and C genome of S.grisebachii than the other known genomes.For utilization of wild species resources,foxtail millet breeders have successfully introduced the naturally mutated herbicide-resistant genes from green foxtail into cultivars,resulting in the herbicide-resistant foxtail millet variety.Here,we review the recent advances of wild species of foxtail millet in species classification,genome constitution and phylogenetic relationships,and highlight the utility of the wild species resources for breeding and domestication of foxtail millet.We also discuss the potentials of the wild Setaria species in discovery of domestication genes and breeding in foxtail millet in the future.