江苏省稻瘟病菌有性态的研究

用标准菌株对1997－1999年在江苏吴江市、宜兴市、通州市、高邮市和赣榆县采集的325个稻瘟病菌单孢分离菌株的可育性和交配型进行了测定,结果表明江苏省稻瘟病菌菌株的育性较低,可交配率为22．77％,可育率仅为7．08％。不同年份、不同地区采集的稻瘟病菌菌株的性亲和力和交配型有较大的差异,三年的交配率分别为26．61％、8．26％和33．64％;通州地区和赣榆地区菌株的交本相对较高,分别为26．15％和25．42％,宜兴地区菌株的交配率较低,只有15．38％。江苏省稻瘟病菌菌株的交配型在不同年份亦出现很大差别,1997年29个可交配菌株中有21个菌株表现为MAT1－2交配型,而1999年36个可交配菌株均为MAT1－1交配型。用江苏省稻瘟病菌的可育菌株进行互交,25个组合中只有6个组合能产生子囊壳和子囊,但均不产生子囊孢子,提示江苏省稻瘟病菌在田间产生健康有性后代的几率不大。对杂交后代的遗传学分析表明,菌株的交配型是受单基因控制的。     

利用原生质体融合研究凤尾菇中性菌株的交配反应

凤尾菇营养缺陷型突变型中性菌株与另一株营养缺陷型的正常交配型菌株进行了原生质体融合反应.融合子之间以及与亲本之间在菌落形态和菌丝生长速度上表现出了较大差异。融合子菌落角变的菌丝体从多核体转变为双核体,并且在菌丝体上产生了圆桶状的特殊结构而不是通常的锁状联合。初步观察表明这些结构似乎与细胞核的迁移有关.对融合子子实体的担孢子进行了遗传分析,结果确证子实体是由两个亲本菌株的融合子产生,同时也表明要对中性菌株交配反应中基因重组进行深入分析还需要进行更多的研究。     

利用原生质体融合研究凤尾菇中性菌株的交配反应

凤尾菇营养缺陷型突变型中性菌株与另一株营养缺陷型的正常交配型菌株进行了原生质体融合反应融合子之间以及与亲本之间在菌落形态和菌丝生长速度上表现出了较大差异。融合子菌落角变的菌丝体多核体转变为双核体,并且在菌丝体上产生了圆桶状的特殊结构而不是通常的锁状联合。初步观察表明这些结构似乎与细胞核的迁移有关,对融合子子实体的担孢子进行了遗传分析,结果确实了实体是由两个亲本菌株的融合子产生,同时也表明要对中性菌株交配反应中基因重组进入深入分析还需要进行更多的研究。     

江苏省稻瘟病菌有性态的研究*

用标准菌株对１９９７～１９９９年在江苏省吴江市,宜兴市、通州市、高邮市和赣榆县采集的３２５个猪瘟病菌单孢分离菌株的可育性和交配型进行了测定,结果表明江苏省稻瘟病菌菌株的育性较低,可交配率为２２．７７％,可育率仅为７．０８％。不同年份、不同地区采集的猪瘟病菌茵株的性亲和力和交配型有较大的差异,三年的交配率分别为２６．６１％、８．２６％和３３．６４％;温州地区和赣榆地区菌株的交配率相对较高,分别为２６．１５％和２５．４２％,宜兴地区菌株的交配率较低,只有１５．３８％。江苏省稻瘟病菌菌株的交配型在不同年份亦出现很大差别,１９９７年２９个可交配菌株中有２１个菌株表现为ＭＡＴ１－２ 交配型,而１９９９年３６个可交配茵株均为ＭＡＴ１－１交配型。用江苏省稻瘟病菌的可育菌株进行互交,２５个组合中只有６个组合能产生子囊壳和子囊,但均不产生子囊孢子,提示江苏省稻瘟病菌在田间产生健康有性后代的几率不大。对杂交后代的遗传学分析表明,菌株的交配型是受单基因控制的。     

简讯

用曹养缺陷型的回复突变株提高谷氨酸生产菌的转化率用亚硝基胍处理谷氨酸生产菌钝齿棒状杆菌(Corynebacterium crenatum)B_9菌株,在100株营养缺陷型     

中国番茄晚疫病菌交配型及其分布研究

本文对中国番茄晚疫病菌交配型的发生和分布及病菌的生物学特性进行了研究,结果表明,我国主要番茄产区晚疫病菌以A1交配型为主,占总菌株数的96.02%;1999~2001年间从全国18个省市采集的201个番茄晚疫病菌株中,仅发现8个A2交配型菌株,分布于广西、云南、河北和福建;被测菌株在10%V8培养基上菌落生长均受到一定的限制,而在黑麦培养基上菌落的生长速度、产孢量有明显的差异,但菌落形态与交配型类型不相关。     

桦纤孔菌有性生殖相关特征及交配型位点分析

对桦纤孔菌菌株MDJCBS88的显微形态、菌丝及担孢子核相进行了观察。采用棉籽壳培养基对担孢子萌发形成的菌株进行栽培试验,筛选出不形成子实体或子实体发育不完整的菌株,将这些菌株在平板上进行了亲和试验,分析桦纤孔菌的有性生殖方式;并基于基因组序列进行交配型基因克隆验证,分析桦纤孔菌的交配型位点结构。显微观察发现,桦纤孔菌菌丝没有锁状联合结构,菌丝细胞无核到多核;子实层担孢子可含0-4个不等的细胞核,不同时期弹射的担孢子含有的细胞核数量不同。桦纤孔菌担孢子萌发率极低,能萌发的担孢子多为早期弹射的担孢子;培养基也影响担孢子的萌发率,与PDA培养基和CYM培养基相比,桦木屑培养基最适合桦纤孔菌担孢子萌发,萌发率为4.55%。从担孢子萌发的96个菌株中获得了2个不结实菌株和9个结实不产孢菌株,占11.5%,这些菌株间亲和试验出现不同的表现特征,包括形成产孢子实体,产生菌丝纽结,相互融合和相互拮抗等现象,认为桦纤孔菌的有性生殖以次级同宗结合为主,并受交配型基因控制。交配型位点克隆测序后分析发现,桦纤孔菌交配型A位点共14 034 bp,含有一个MIP基因和两组HD1和HD2基因;交配型B位点包含3个疑似信息素受体基因和1个信息素前体编码基因。     

费氏丙酸菌维生素B_1营养缺陷型菌株的诱变选育

在丙酸发酵过程中,乙酸为主要副产物,维生素B1与乙酸合成途径相关,筛选维生素B1营养缺陷型突变株有助于降低乙酸的合成,提高丙酸的产量。以费氏丙酸菌IFFI.10019作为出发菌株,经过紫外线诱变处理,筛选育种获得维生素B1营养缺陷型费氏丙酸菌二株,其中Pf007菌株的丙酸产量由原来的1.1 g/L提高到2.1 g/L,提高率达到91%。     

kar交配法转移YACs至新宿主的研究

利用改进的kar交配法,将一个含有340kb人基因组DNA的YAC片段的供体酵母菌株YAC23与受体菌株YLB504进行交配,以选择平板对所形成的候选YAC导入菌进行筛选。经PCR分析,候选YAC导入菌在404bp处有一个扩增带,即具有受体菌株的交配型(MAT α)。进一步用脉冲电泳进行核型鉴定,证实YACs己成功地进入受体,实现了YACs从一个宿主到另一个宿主之间的转移。     

华山松印度块菌菌根中的块菌交配型基因的初步研究

印度块菌属于子囊菌门异宗配合真菌,其交配型基因(mating type gene)的表达调控与块菌子囊果的形成和发育直接相关。已有研究表明在种植园内,两种交配型基因竞争性地感染宿主植物且不同交配型菌株的时空分布吻合概率可能是决定子实体产出及产量的关键因素之一。为增加印度块菌子囊果形成的几率,本研究以交配型基因MAT1-1-1及MAT1-2-1作为分子标记,检测了接种印度块菌菌剂后6个月、24个月和36个月的华山松菌根中块菌的两种交配型基因的动态变化,结果表明接种后24个月的单株苗存在两种交配型基因的菌根苗占总菌根苗的比例最高,暗示在此时间点进行块菌菌根苗室外移栽,有望在后期提高两种交配型菌株的时空分布吻合概率,从而提高子实体产生的几率。     

THE INDUCTION OF BIOCHEMICAL AND MORPHOLOGICAL MUTANTS IN THE MOSS PHYSCOMITRELLA PATENS

Physcomitrella patens is a monoecious, cleistocarpous moss which completes its life cycle under defined conditions in 7 to 8 weeks. Sexual reproduction is readily obtained by culturing gametophytes at 15 to 19 C. Mutants were induced by treatment of either spores or protonemal cells with ethyl methane sulfonate, N-methyl-N'-nitro-N-nitrosoguanidine and X-rays. Thiamine, para-aminobenzoic acid, niacin and yeast extract auxotrophs were obtained. Growth response to various supplements was studied in the auxotrophic mutants. Five yellow mutants and two morphological mutants were induced. The chlorophyll content of the yellow mutants is reduced 35-65% of wild type. The self-sterile, para-aminobenzoic acid-dependent mutant was used as the archegonial parent in crosses with a yellow mutant and a morphological mutant. The self-sterility of the para-aminobenzoic acid-requiring mutant appears to be pleiotropically related to the auxotrophic condition, since self-sterility does not segregate from nutritional dependence in progeny of crosses. On the basis of tests with heterozygous diploids obtained by aposporous regeneration of capsule cells, two mutant alleles were shown to be recessive to their respective wild-type alleles.     

The spectrum of auxotrophic mutants from the liverwort Sphaerocarpos donnellii Aust.

Summary Thirteen nutritionally deficient mutants have been found amongst 22,553 plants raised from X-ray irradiated spores of the liverwort Sphaerocarpos donnellii Aust. Of the thirteen mutants four require nicotinic acid two choline and four arginine. Two strains must be supplemented with glucose but one is distinguishable by its pale green colour. One strain requires yeast extract in addition to glucose. The auxotrophic mutants of Sphaerocarpos donnellii identified in these studies are discussed in relation to those already found in other green plants, viz. Chlamydomonas reinhardi, Chl. eugametos, Marchantia polymorpha, Physcomittella patens, Todea barbara, Arabidopsis thaliana, and Lycopersicum esculentum.     

Genetic interaction observed in Bacillus subtilis

Summary Some evidence was obtained that genetic interaction occurs inBacillus subtilis K. A mixed inoculation of two doubly auxotrophic mutants onto approriate media yielded tiny colonies which seemed to be initiated by heterocaryons or heterozygotes. The tiny colonies contained not only a recombinant type which acquired two characters from one or another parent, but also some abnormal types having new characters which were not recognized in either parent. The phenomenon is similar to the genetic interaction found inStreptomyces.With 5 Figures in the Text     

Intraspecific heterokaryon and fruit body formation in Coprinus macrorhizus by protoplast fusion of auxotrophic mutants

Summary Fusion of protoplasts of Coprinus macrorhizus mutants with different amino acid requirements resulted in the production of prototrophic clones at frequencies of 1–4% of the protoplasts surviving the fusion treatment. The frequencies were at least 200 times higher than those of the appearance of revertants. Few prototrophic colonies appeared also when the mutant protoplasts were individually subjected to fusion treatment, or when they were mixedly cultured without fusion treatment. It was thus concluded that intraspecific heterokaryons were formed by protoplast fusion.The auxotrophic mutants did not form fruit bodies when cultured singly or mixedly with each other. In contrast, the heterokaryons produced by protoplast fusion between the mutants of compatible mating types developed into fruit bodies with intermediate morphology of those of the strains from which the mutants were derived. Heterokaryons were also formed by fusion of mutant protoplasts with identical mating genotype, but they failed to form fruit bodies.Abbreviations PEG polyethyleneglycol - HEPES N-2-hydroxyethylpiperazine-N-2-ethane sulfonic acid     

Monokaryotization by protoplasting heterothallic species of edible mushrooms

After regeneration of protoplasts of seven heterothallic of edible mushrooms, two types of monokaryons were recovered, being identified by the absence of clamp connections. In regenerated colonies, monokaryons grew more slowly than dikaryons and so could be distinguished from them. In all species, the yield of monokaryons in the regenerated colonies was over 45%. The mating types and auxotrophic markers were the same in the protoplasted monokaryons and parental monokaryons. In comparison with other monokaryotization methods, protoplasting is rapid, simple and effective; its applications in breeding of edible mushrooms are discussed.     

凤尾菇和桃红平菇种间原生质体电融合获杂种菌株

以有自然标记的双核风尾菇(Pleurotus sajor-caju)和桃红平菇(P．Rhodophyllus)为出发菌株,以它们携带营养缺陷型标记的单孢菌株为直接亲本,采用BAEKON 2 000基因转移仪进行侧耳属种间原生质体电融合,成功地获得若干株融合体,其中有一株编号为F57的融台体已培育出子实体。比较了融合体F57与亲本的形态、生理、生化和遗传等性状,结果证实,融合体F57是一株新的种间杂种菌株。     

香菇亲本菌株及其杂交后代的RAPD分析

运用随机扩增多态性DNA（RandomamplifiedpolymorphicDNA,RAPD）技术对源于两个香菇（Lentinulaedodes）双核菌株的孢子单核体、原生质体单核体及其杂交后代进行了基因组DNA多态性分析。用9个随机引物共扩增出116条DNA片段,其中82．5％具有多态性。综合分析9个随机引物的扩增谱带,可将所有供试亲本单核体清楚地分开,且早核体聚类分析的结果与其来源及遗传背景相吻合。此外,用两个双核亲本菌株的各4个不同交配型的孢子单核体两两支配所得的所有杂交组合,也均可与双核亲本菌株明确地区分开来。因此,在杂交育种中,RAPD分析可为亲本的选配及杂种的鉴定提供可靠依据。     

香菇亲本菌株及其杂交后代的RAPD分析*

运用随机扩增多态性DNA（RandomamplifiedpolymorphicDNA,RAPD）技术对源于两个香菇（Lentinulaedodes）双核菌株的孢子单核体、原生质体单核体及其杂交后代进行了基因组DNA多态性分析。用9个随机引物共扩增出116条DNA片段,其中82．5％具有多态性。综合分析9个随机引物的扩增谱带,可将所有供试亲本单核体清楚地分开,且早核体聚类分析的结果与其来源及遗传背景相吻合。此外,用两个双核亲本菌株的各4个不同交配型的孢子单核体两两支配所得的所有杂交组合,也均可与双核亲本菌株明确地区分开来。因此,在杂交育种中,RAPD分析可为亲本的选配及杂种的鉴定提供可靠依据。     

Monokariotic fruiting body and clamp cell formation in Mycoleptodonoides aitchisonii (Bunaharitake)

The ability to produce monokaryotic fruiting bodies and clamp cells in culture was examined in monokaryotic strain isolated from several dikaryotic parental strains of the edible mushroom, Mycoleptodonoides aitchisonii (Bunaharitake). We describe a single dikaryotic M. aitchisonii strain, TUFC50005, and 20 monokaryons derived from it, which exhibited a wide spectrum of monokaryotic fruiting types. Most strains formed primordia, or young fruiting body-like structures, but only one of the monokaryons, strain TUFC50005-4, formed a fruiting body, even though it had only one nucleus and produced only two spores after meiosis. We demonstrated that dikariotization was not required for clamp cell formation, fruiting body formation, or meiosis, in this mushroom.