药用植物菘蓝的遗传及远缘杂交研究进展

Advances in Genetics and Distant Hybridization of Medicinal Plant Isatis indigotica

十字花科菘蓝为我国大宗常用中药材植物,其叶和根分别是大青叶和板蓝根的原料。本文总结了菘蓝的基因组结构、生物活性成分及其生物合成途径、远缘杂交及新材料创建等方面的研究进展。菘蓝(2n=2x=14)的基因组大小为300 Mb,为tPCK核型,3万余蛋白编码基因。高质量的基因组测序解析了菘蓝的主要生物活性成分吲哚生物碱、苯丙烷类、萜类的合成途径及其候选基因。由于染色体消除,菘蓝(父本)与白菜及甘蓝型油菜的族间有性杂交只产生了具有少数菘蓝遗传成分的非预期杂种。菘蓝与萝卜的体细胞杂种具有双亲染色体,但自交及回交均未产生后代。菘蓝与白菜的体细胞杂种具有加倍的菘蓝染色体组,花粉部分可育而雌性不育。菘蓝与甘蓝型油菜的体细胞杂种与甘蓝型油菜连续回交后创建了全套的7个甘蓝型油菜-菘蓝附加系,一些附加系具有比菘蓝更强的广谱抗病毒效果;体细胞杂交中发生的双亲线粒体基因组重组导致甘蓝型油菜新细胞质雄性不育系的产生,菘蓝特定染色体上的育性基因导入培育了恢复系。最后讨论了这些附加系对菘蓝遗传研究的价值及开发利用前景。

Chinese woad(Isatis indigotica Fort.,2n=14;Radix Isatidis)is the traditional Chinese medicinal plant widely used in China,and serves as the germplasm resources in crop genetic improvement.This article reviews the progresses in the genomic structure,bioactive compounds and their biosynthesis,as well as distant hybridization with other crop species.The genome size of Chinese woad is about 300 Mb with the tPCK karyotype and 30,000 protein coding genes,and the high quality reference genome reveals the candidate genes and synthesis pathways for main bioactive compounds,indole alkaloids,phenylpropanoids and terpenoids.Through making crosses(male parent)with Brassica rapa and B.napus,the non-classical hybrids containing few chromosomes and fragments of Chinese woad are produced.The somatic hybrids with radish were found with chromosomes of both parents,while they failed to produce seeds by either selfing or backcrossing.The somatic hybrids with B.rapa ssp.chinensis(L.)P.Hanelt show its duplicated chromosomes but male fertile.The somatic hybrids with B.napus derive the whole set of rapeseed-woad additional lines,after successive backcrossing with B.napus.Several lines,if compared to the woad,showed improved resistance against many viruses.The recombinant mitochondria DNA molecule produced during the somatic fusion causes the new cytoplasmic male sterility,and the fertility restoration is realized by the introgression of the gene(s)from one particular chromosome of woad.Finally,we discuss the future genetic study and their utilization based on their novel additional lines.