甘薯及其近缘野生种Ipomoea lacunosa种间体细胞杂种的特性鉴定和遗传组成分析

Characterization and genetic component analysis in a somatic hybrid between Ipomoea batatas(L.) Lam. and I. lacunosa

以甘薯(Ipomoea batatas)品种‘徐薯18’(2n=6x=90)及其近缘野生种I.lacunosa(K61,2n=2x=30)的种间体细胞杂种XL1为材料,利用形态学与细胞学分析、酯酶同工酶、重金属离子胁迫的离体鉴定、扩增片段长度多态性(AFLP)、甲基化敏感扩增多态性(MSAP)等技术对XL1的特性和遗传组成进行了分析。结果表明,XL1对铝和铬的耐受性显著高于‘徐薯18’,胁迫条件下,XL1的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著高于‘徐薯18’,而丙二醛(MDA)含量显著低于‘徐薯18’。XL1的基因组含有双亲的特异条带和改变的条带,XL1的胞嘧啶甲基化位点由双亲的特异位点和改变的位点组成,XL1中‘徐薯18’特异的基因组条带和甲基化位点比例显著高于I.lacunosa的比例。XL1具有与‘徐薯18’相同的叶绿体和线粒体基因组组成。本研究进一步证明了体细胞杂交在甘薯遗传改良上的重要作用,同时,本研究结果将有助于甘薯近缘野生种中的有益基因发掘,也有助于进一步理解甘薯栽培种的进化和系统发育。

Characteristics and genetic components of a somatic hybrid, XL1, between sweetpotato （lpomoea batatas） cv. ＇Xushu 18＇ （2n=6x=90） and its wild relatives 1. lacunosa （2n=2x=30） were systematically studied through morphological, cytological and esterase isozyme analyses, in-vitro assay for heavy metal stress toler- ance, amplified fragment length polymorphism （AFLP） and methylation-sensitive amplified polymorphism （MSAP） analyses. The results showed that XL1 exhibited significantly higher tolerance to heavy metal alumi- num （A13＋） and chromium （Cr6＋） stresses compared to ＇Xushu 18＇. Superoxide dismutase （SOD） and catalase （CAT） activities were significantly increased, while malondialdehyde （MDA） content was significantly de- creased compared to ＇Xushu 18＇ after exposure to various concentrations of Al3~ and Cr6~. XL1 had genomic DNA band patterns consisting of both parent specific bands and changed bands; its DNA methylation site pat- terns consisted of both parent specific sites and changed sites. Further analysis demonstrated that XL 1 had the much higher proportions of ＇Xushu 18＇ specific genomic DNA bands and methylation sites compared to those of/. lacunosa. XL1 had the same chloroplast and mitochondrial genomes as ＇Xushu 18＇. These results show the significance of somatic hybridization techniques in the genetic improvement of sweetpotato, and will aid in ex- ploring the useful genes of/. lacunosa and understanding the evolution and phylogeny of the cultivated sweet- potato.