【摘要】 通过原生质体融合和秋水仙素加倍技术，将糖化酵母的3个等效异位基因（STA1、STA2和STA3）分别构建成交配型位点等位基因纯合（a／a）、和糖化酶基因各自纯合加倍的纯合二倍体（STA1／STA1、STA2／STA2和STA3／STA3）以及糖化酶基因相互组合加倍的组合二倍体（STA1／STA2、STA2／STA3和STA1／STA3）。研究了这3个糖化酶基因表达的剂量效应及其相互关系。糖化酶酶活测定的结果表明，在交配型位点等位基因纯合状态下，糖化酶基因的剂量效应明显。例如，1株纯合二倍体SFY56-6的酶活可达其单倍体亲株的2．35倍，而1株纯合三倍体SFY56-104其酶活是亲株的3．18倍。糖化酶基因组合二倍体的酶活也表现出不同程度的组合剂量效应。更多还原

【Abstract】 Diploid strains homozygous for both MAT allele and STA genes (a/a. STA1/ STA1 or STA2/ STA2 or STA3/ STA3) and diploid strains homozygous for MAT allele but intercombinahve for STA genes (a / a. STA1/ STA2 or STA2/ STA3 or STA1/ STA3) were constructed by means of the protoplast fusion or the colchicine beatment.According to glucoamylase activity in YPS medium, we studied the gene-dosage effect and their interrelation of these three polymeric genes coding for glucoamylase. The results of the glucoamylase activity determination showed that the gene-dosage effect of glucoamylase is obvious in diploid and triploid strains homozygous for both MAT allele and STA gene, such as the glucoamylase achvity of a diploid strain SFY56-6 and a triploid strain SFY56-104 homozygous for both MAT allele and STA genes were respectively 2.35 and 3.18-fold as compared with that of the their parental strain IATA-Y56 that is a haploid Aaccharomyces diastaticus. Moreover, the glucoamylase achvity of diploid stains homozygous for MAT allele but intereombinative for STA genes also showed the combinative gene-dosage effect to a certain extent.更多还原