甘蓝型油菜EMS诱变矮秆突变体分析

Analysis of Dwarf Mutants Induced by EMS in Brassica napus

本研究分析了甲基磺酸乙酯(ethylmethylsulfone,EMS)诱变甘蓝型油菜矮秆突变体Bnd2(Brassica napus dwarf 2)的农艺性状、矮秆性状遗传特性以及对不同植物激素的响应。农艺性状分析结果显示:成熟期Bnd2株高、有效分枝高度、伸长节数、节间距、主花序有效长度显著低于诱变亲本2B。矮秆性状遗传分析结果显示:回交F1代株高偏向亲本2B,表现为高秆,F2群体高秆与矮秆的分离比符合3∶1的分离规律,表明Bnd2矮秆性状受单个隐性基因控制。不同植物激素处理结果显示:Bnd2幼苗下胚轴比2B要短,但Bnd2幼苗下胚轴对赤霉素(gibberellin,GA)的响应减弱,对油菜素甾醇(brassinosteroid,BR)的响应增强,且BR处理可恢复Bnd2幼苗的下胚轴表型,推测Bnd2的矮秆性状可能与GA信号和/或BR合成有关,这为后期矮秆基因定位提供了线索。

The agronomic traits and genetic characteristics of dwarf mutant Brassica napus dwarf 2(Bnd2)induced by ethylmethylsulfone(EMS)and its responses to different plant hormones were analyzed.Analysis of agronomic traits showed that the plant height,effective branch height,number of elongated internode,internode length and effective length of raceme of Bnd2 at maturity were significantly lower than those of the mutagenized parent 2B.Genetic analysis of dwarf traits showed that the plant height of backcross F1 generation deviated to its parent 2B,which was tall,and the ratio of tall plants to the dwarf plants in F2 generation was 3︰1,indicating that the dwarf traits of Bnd2 mutant were controlled by a single recessive gene.The results of different hormone treatments showed that the hypocotyls of Bnd2 seedlings were shorter than those of 2B seedlings,but the hypocotyls of Bnd2 seedlings were less responsive to gibberellin(GA)and more responsive to brassinosteroid(BR).Moreover,BR treatment could restore the hypocotyl phenotype of Bnd2 seedlings,suggesting that the dwarf traits of Bnd2 might be related to GA signal and/or BR synthesis,which provided clues for the later dwarf gene mapping.