利用甲基磺酸乙酯和枯萎病菌毒素诱变筛选香蕉抗毒素突变体

Screening of Mutants Resistant to the Toxin Produced by Fusarium oxysporum f.sp.cubense Using Ethyl Methane Sulfonate and Toxin Mutagenesis Techniques

以化学诱变剂甲基磺酸乙酯(EMS)和香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense)4号生理小种的粗毒素为诱变剂,以香蕉愈伤组织和分化芽为筛选材料,通过多步筛选法,优化了筛选体系,并筛选出了抗香蕉枯萎病菌毒素的突变体。以体积百分比浓度为0.5%的EMS分别处理香蕉愈伤组织和分化芽40min,获得"半致死剂量"效应,对存活的香蕉愈伤组织和分化芽在依次递增的粗毒素浓度(5.0%→10.0%→12.5%)胁迫下进行定向筛选,获得了抗香蕉枯萎病菌毒素的愈伤组织块和分化芽,从抗病分化芽突变体获得了再生植株。对再生植株抗毒素的性能进行鉴定,其病情指数(24.72)显著低于对照植株(96.11),抗毒素效果达到74.28%。

The calli and differentiation buds of banana were treated with chemical mutagen ethyl methane sulfonate （EMS） and the crude toxin produced by Fusarium oxysporum f. sp. cubense race 4 （Foc 4）, the causal agent of banana fusarium wilt, via a multi-step screen method. As a result, an optimized screen system was established and the resistant mutants were obtained. The optimized screen system as follows, Firstly, the calli and differentiation buds of banana were treated with 0.5% （v/v） of EMS for 40 minutes which resulted in the effect of＂ semi-lethal dose＂; Then, the survived calli and differentiation buds of banana were screened directionally under the stress of successively increasing concentrations （5.0%→10.0%4 12.5%） of Foc 4 crude toxin; And finally, toxin-resistant calli and toxin-resistant differentiation buds were successlly obtained by using this multi-step screen method. The regenerated banana plantlets derived from toxin-resistant mutants of differentiation buds were tested for their resistance to Foe 4 toxin, the results showed that the disease index （24.72） of mutant plantlets was significantly lower than that （96.11） of control plantlets, and the effect of toxin-resistance reached 74.28%.