灭蚊真菌贵阳腐霉原生质体诱变育种实验研究

An Experimental Study on Mutation Induction Technique of Pythium guiyangense Su,A Fungal Pathogen of Mosquitoes

目的:建立采用紫外线和氯化锂诱导灭蚊真菌发生突变的方法,为培育理想菌株开辟新的途径。方法:对出发菌株贵阳腐霉的原生质体进行诱变处理,通过正突变率与紫外、化学诱变剂量的相互关系,确定最佳诱变条件,经过酪蛋白平板透明圈和菌粉得率粗筛突变株,连续8代传代培养及摇瓶实验检测突变株的遗传稳定性。结果:当用0.6%氯化锂处理90min时,突变株的致死率和正突变率分别为86.9%和26.9%;用20W紫外灯30cm照射180s,突变株致死率为81.3%、正突变率为78.5%;筛选了7株突变株,其中U22经传代实验证明其遗传性状稳定。结论:本研究所建立的对贵阳腐霉原生质体诱变系统基本成功,为该菌的细胞工程育种创造了条件。

Objective： To establish a mutation induction system for mutation breeding of Pythium guiyangense Su, a fungal pathogen of mosquitoes. Methods： Protoplasts of original strain were treated with UV or LiC1 for mutation induction. Casein plate transparent loop method and mycelial weight determine were used to screen mutant colonies. Pertinent induction condition combination were summarized based on the analysis of the relationship between the positive mutation rates and treatment dosages and periods of UV or LiC1. One of the mutational colonies was continuously cultivated for 8 generations on KPYG2 plates for the observation of genetic stability. Results： A lethal rate of 86.9% and a posi- tive mutation rate of 26.9% were achieved when the protoplasts were treated by 0.6% of LiCl for 90mins, and a lethal rate of 81.3% and a positive mutation rate of 78.5% were obtained when the protoplasts were irradiated by a UV lamp of 20W in a distance of 30cm for 180s. Seven mutants were obtained, and one of them, U22, was proved genetically stable. Conclusions ： The mutation induction system of P. guiyangense by UV and LiCl is successful, and can provide basis for the mutation breeding of P. guiyangense in the future.