Mitochondrial Microsatellite Variability of Tobacco CMS Lines with Four Dif-ferent Cytoplasms

Abstract

Sequence variation of the mitochondrial DNA has a direct relation with cytoplasmic male sterility(CMS).In this study,we analyzed mtSSR variability of four sterile cytoplasm types,including four CMS lines,their maintainer lines and sterial cytoplasm sources,and explored the relationship between mtSSR variability and CMS.Based on the entire mitochondrial DNA sequence of Nicotiana tabacum,we identified 39 mtSSR loci having more than ten mononucleotide repeats and 24 mtSSR markers that can be used to analyze mitochondrial DNA variability of four sterile cytoplasm types.The results showed that the mtSSR polymorphism was very low in N.tabacum,which was 10.5%,and there were some different loci between the CMS lines and their maintainer lines,the wild tobacco provided the sterile cytoplasm.Such as,in the Nat(sua.)S,the different loci were located in coding regions of orf138a,orf138c and intergenic region orf102-orf210;in the Nat(gla.)S,the different loci were located in two coding regions of orf138a,orf138c and four intergenic regions nad2-sdh3,rps12-orf125b,orf116-orf101b,orf102-orf210;in the Nat(rep.)S,the different loci were located in coding region orf190 and intergenic region orf104c-orf202;in the Nat(rus.)S,the different loci were located in cod-ing regions of orf137 and rps12-orf125b.These different loci likely related to their CMS.The results also showed that the fragments of 184,172,212 and 225 bp were amplified by mtSSR primer TMS20 in four types of CMS of ms G-28,86-6,98-43,116,respec-tively,and using this primer we could distinguish the four types of CMS of Nat(sua.)S,Nat(gla.)S,Nat(rep.)S,Nat(rus.)S between each other.