一个水稻显性高秆突变体的遗传分析和基因定位

摘要

从水稻(Oryza sativa L.)的两个半矮秆籼稻品种6442S-7和蜀恢881杂交F2代群体中发现一个高秆突变体D111,其株高和秆长分别比亲本蜀恢881增加63.0%和87.0%.用205个微卫星标记分析D¨1及其原始亲本6442S-7和蜀恢881之间的基因组DNA多态性,结果未发现D111具有2个原始亲本都没有的新带型,证明D1¨的确是6442S-7和蜀恢881的杂交后代发生基因突变产生的.将D111分别与蜀恢881、蜀恢527、明恢63、9311、IR68、G46B等6个半矮秆品种和高秆对照品种南京6号杂交,分析F1和F2代株高的遗传行为,结果表明D1¨的高秆性状由一对显性基因控制,且该基因与南京6号的高秆基因紧密连锁或等位.以蜀恢527/D111 F2群体为定位群体,运用微卫星标记将D111显性高秆突变基因定位于水稻第一染色体长臂,与RM212、RM302和RM472的遗传距离分别是27.7 cM、25.5 cM和6.0 cM,该基因暂命名为LC(t).认为D111是首例从半矮秆品种自然突变产生的水稻显性高秆突变体,LC(t)为首次定位的水稻显性高秆突变基因.此外,将上述基因定位结果与Causse等(1994)和Temnykh等(2000,2001)发表的水稻分子连锁图谱进行比较,发现LC(t)基因恰巧位于与水稻"绿色革命基因"sd1相同或十分相近的染色体区域,因此,还就LC(t)基因与sd1基因之间的可能关系进行了讨论.%A new long-culm mutant "D111" was discovered in breeding materials of rice (Oryza sativa L). Polymorphic analysis of microsatellite markers demonstrated that D111 derived from a gene mutation in the crossing progenies of two semidwarf varieties 6442S-7 and Shuhui 881. Plant height and culm length of D111 increased by 63.0% and 87.0%, respectively, compared with those of its parent Shuhui 881.Genetic analysis suggested that the long-culm trait of D111 was controlled by a pair of dominant genes, and the long-culm gene of D111 was tightly linked or allelic to that of long-culm control variety Nanjing 6.Molecular marker analysis showed that the mutant gene of D111 located on the long arm of rice chromosome 1, 27.7 cM, 25.5 cM and 6.0 cM from microsatellite markers RM212, RM302 and RM472,respectively. This Iong-culm mutant gene was designated tentatively as LC(t). It was considered that D111was the first rice example of dominant long-culm mutant derived from spontaneous mutation of semidwarf varieties and that LC(t) was the first mapped long-culm mutant gene of rice. In addition, the possible relationship between LC(t) gene and rice "green revolution gene" sd1was discussed.