以含中節片段異源染色體添加系從事菸草的基因定位

Abstract

以含二套Nicotiana. plumbaginifolia (2n＝20)染色體及一套N. sylvestris (n＝12)染色體的異源三倍體體細胞雜種（2n＝32）與二倍體N. plumbaginifolia回交產生的5株染色體2n＝23-25的添加系，再與N. plumbaginifolia回交後，得到13株含二套N. plumbaginifolia及一條含N. sylvestris中節片段的異源單染色體添加植株。添加之N. sylvestris中節片段經由分析RFLP標誌及核型分析鑑定。分析分佈於九條N. sylvestris染色體之66個RFLP標誌的結果，其中10株染色體添加系之N. sylvestris染色體片段，分屬於N. sylvestris之第6, 7, 8, 9, 10, 12條染色體，其餘三株中有一株於植株維持過程中發生染色體片段丟失，另兩株則未檢定出。綜合染色體型態觀察、RFLP標誌分析、5S rDNA之螢光原位雜交以及Suen等人（1997）4株染色體轉座添加系和2株染色體丟失添加系的資料，繪製N. sylvestris之第6, 7, 8, 9, 10, 12條染色體之標誌分區圖。

A sesquidiploid hybrid (PPS, 2n = 32) between Nicotiana plumbaginifolia (PP, 2n = 20) and N. sylvestris (SS, 2n = 24) was backcrossed to N. plumbaginifolia to produce monosomic alien addition lines. A total of 13 2n = 20 + 1 f (f: fragment) plants, each containing two sets of N. plumbaginifolia chromosomes and a centric fragment of N. sylvestris chromosome, were obtained from the 5 hyperploids (2n=23-25) of the BC1 generation backcrossed again to N. plumbaginifolia. The centric fragments of N. sylvestris chromosome in these plants were identified by RFLP and karyotype analyses. Among the 66 RFLP markers distributed on 9 N. sylvestris chromosomes tested, the centric fragments of the 10 telomonosomic alien addition lines corresponded to chromosomes 6, 7, 8, 9, 10 and 12, respectively. One addition line of the remaining 3 lost the centric fragment during plant maintenance and the other two lines was detected in no N. sylvestris - specific DNA band. Based on chromosome morphology, RFLP markers analysis, fluorescence in situ hybridization of 5S rDNA, data of 4 translocation and 2 deletion addition lines (Suen et al., 1997), the distributions of markers among N. sylvestris chromosomes 6, 7, 8, 9, 10 and 12 were illustrated.