Genetic analysis of genes in mutants of graminicolous leaf-blight fungi

与突变基因的交叉实验揭示了植物病原真菌的遗传信息，对于阐明这些寄生虫的性质是必不可少的。在本项目中，我利用突变基因在试管中形成有丝分裂相，为禾本科叶枯病真菌子囊孢子分析奠定了基础。一些植物病原真菌中的无性型-无性型联系及其应用综述了包括禾本科叶枯病真菌在内的一些植物病原真菌中的无性型-无性型联系。子囊-子囊孢子在受控的实验室条件下产生，并与分生孢子产生进行了比较。也证实了黑胡椒黑斑病病原菌的子囊孢子散布。研究了N-甲基-N-硝基-N-亚硝基-N-亚硝胺(MNNG)、甲烷磺酸乙酯(EMS)、紫外线、射线等4种诱变剂对Cochliobolus terostrophus的致死和诱变作用。MNNG和EMS在诱导突变方面几乎同样有效。在MNNG治疗组和EMS治疗组中，突变基因的最高存活率分别为5%和1.4%。Cochliobolus herostrophus突变体基因的遗传分析通过化学诱变获得了5种颜色突变体。确定了突变体的遗传缺陷位点。在黑色素生物合成中，携带Alb1、Scy、Brn和PGR的突变株的遗传缺陷位点分别位于五酮的环化、司他林的转化、1，3，8-THN的转化和1，8-DHN的氧化。杂交试验结果表明，Lb1、Alb2和Brn紧密连锁，Scy和Pgr为同一连锁群。还获得了携带Pol的多恶英抗性突变体。POL与上述基因座分离独立。

Crossing experiments with mutants genes, that reveal genetic information about plant pathogenic fungi are essential for elucidationg the nature of these parasites. In this project, I have confirmed the basis for ascospore analysis of graminicolous leaf-blight fungi by using teleomorph formation with mutant genes in vitro.1. Anamorph-teleomorph connection in some plant pathogenic fungi and its application; Anamorph-teleomorph connection in some plant pathogenic fungi including graminicolous leaf-blight fungi were summarized. Ascocarp-ascospore production under controlled laboratory conditions have demonstrated and compared with conidium production. Ascospore dispersion of the causal agent of Nectria blight of Piper nigrum in the field was also confirmed.2. Comparison of mutagenes in Cochliobolus heterostrophus mutagenesis; Lethal and mutagenic effects of four kinds of mutagenes (N-methyl-N-nitro-N-nitrosoguanidine(MNNG) ethyl methanesulfonate(EMS), UV light, -ray) on the fungus were studied. MNNG and EMS are almost equally effective in inducing the mutants. The maximum frequency of mutants among the suvaivors was at ca. 5 % survival in MNNG treatment and at 1.4 % survaival in EMS treatment.3. Genetic analysis of genes in mutants of Cochliobolus heterostrophus; Five types of color mutants were obtained through chemical mutagenesis. The genetic deficient sites of the mutants were determined. The genetic deficient sites of mutants carring Albl,Scy,Brn, and Pgr were at the cyclization of pentaketide, conversion of scytalone, conversion of 1,3,8-THN, and oxidation of 1,8-DHN respectively, in the melanin biosynthesis. The results of crossing experiments indicated that lbl,Alb2 and Brn were closely linked, and that Scy and Pgr were same linkage group. Polyoxin resistant mutant carring Pol was also obtained. Pol was segregated indipendently from above mentioned loci.