茶树菇原生质体再生及单核体菌株的特性

【背景】茶树菇遗传育种工作是茶树菇产业持续发展的保障和关键,原生质体的制备及单核体菌株的获得可为茶树菇遗传育种工作的开展提供技术支持。【目的】获得茶树菇原生质体的再生特性、单核化特性及其交配型,为开展茶树菇的杂交育种、融合育种、诱变育种、遗传转化和功能基因挖掘等奠定基础。【方法】以茶树菇保藏菌种Aa11的菌丝为材料,采用甘露醇溶液和溶壁酶溶液直接处理平板菌丝制备茶树菇原生质体,而后对原生质体进行分离和再生培养。通过原生质体单核菌丝体两两单单对峙培养,观察对峙培养过程中的菌落形态变化。【结果】当接种块数量为7、酶解温度为33-34℃、酶解时间为60-80 min时,原生质体数量为107个/mL。茶树菇原生质体在涂布平板7 d后肉眼才可见明显的再生菌落形成,在再生培养基上再生率为0.71%,单核化率为41.1%;再生异核体和再生单核体在形成再生菌落时有时间差,从第7天开始往后连续3 d的再生菌落均为异核体菌株,往后第4天开始陆续出现单核体菌落,之后时间内的菌落均为单核体菌株。试验共得到290个原生质体单核体,分为A1B1和A2B2两种亲本交配型,A1B1和A2B2二者的比例为138:152...     

茯苓原生质体单核化及同核体杂交

茯苓Wolfiporia hoelen是一种食药兼用的大型真菌,在我国栽培历史悠久,但由于长期无性繁殖,导致菌种退化,栽培产量下降,严重影响产业发展。为解决茯苓育种的难题,我们前期建立了茯苓同核体鉴定方法,明确了其交配系统,建立了单孢同核体杂交育种体系,但是部分茯苓菌株子实体形成困难或子实体贴生,导致担孢子收集困难,因此原生质体单核化的研究具有重要意义。本研究以两株存在较大遗传差异且同核体类型不同的菌株776和775为材料,核荧光染色表明超过60%的原生质体具有细胞核,原生质体再生率分别为11.0%和7.6%,不易生长的再生菌株中既有同核也有异核菌株。原生质体单核化获得了两个菌株的同核体菌株,比例可达到10%以上,菌株776获得了两种交配型的同核体菌株(5:3),不存在偏分离(χ²=0.5),但菌株775原生质体单核化仅获得了一种交配型的同核体菌株,表现出严重的交配型偏分离。通过杂交菌株与两亲本对峙试验及基于rpb2的杂合位点验证,证实获得了原生质体同核体杂交菌株25株,原生质体同核体与单孢同核体杂交菌株50株,表明茯苓原生质体同核体杂交育种的可行性。     

中国香菇交配型和基因型的分析

自1987—1990,在长江以南九省(区)采集52个香菇品系,43株制作了孢子印用以检测交配型,又以检测A.B因子位点的等位基因方法测定了担孢子的基因型,保藏了以A_xB_x(或A_xB_y……)标记的标准单核菌丝体,这是建立中国香菇种质库的第一步,将为香菇杂交育种提供有效亲本。结果表明:每一菌株的四个交配型呈随机分配。具有四个交配型的菌株百分率是79%,有二个交配型的香菇菌株百分率是21%。有9个菌株的单核菌丝的基因型从A_1B_1……A_(18)B_(18)不同,A.B因子等位基因差异明显,这些菌株显示了A.B因子的很低的地区性重复频率。本项研究中建立了区分同宗A同宗B以及四个交配型的试验方法,遵循着核移动的规律,这个方法能够重复。     

金针菇子实体颜色的遗传规律研究

以金针菇黄色菌株F19和白色菌株F8801为亲本,原生质体单核化获得两亲本的单核菌株,配对杂交获得F1,从F1的子实体分离单孢菌株,与两亲本的原生质体单核化菌株进行回交配对,出菇观察子实体颜色,分析菇体颜色的遗传规律。研究结果表明,黄色为显性、白色为隐性,菇体颜色受一对基因(Cc)控制,与不亲和性因子A或B都没有连锁。     

灵芝尿嘧啶营养缺陷型菌株的筛选和分子鉴定

【背景】营养缺陷型是一种应用广泛的分子标记,但是目前在灵芝中还未有研究和应用报道。【目的】为灵芝遗传转化研究、杂交育种和菌种鉴别提供亲本材料和技术支持。【方法】采用紫外光诱变、单单杂交、孢子单核化的方法从灵芝单核体菌株出发得到尿嘧啶营养缺陷型双核体菌株。【结果】获得8株稳定的尿嘧啶营养缺陷型单核体突变菌株和7株尿嘧啶营养缺陷型双核体菌株。【结论】灵芝尿嘧啶营养缺陷型菌株在添加外源营养物的基础上可恢复正常生长,可以为灵芝遗传转化体系的构建和灵芝育种提供材料。     

B交配型位点基因对杏鲍菇极性的鉴定

[目的]用B交配型位点基因对杏鲍菇不同极性菌株进行快速鉴定。[方法]根据杏鲍菇B交配型位点基因的信息素PEphb(3.3.1~3.3.4)和信息素受体PEPHSTE(3.3.1~3.3.4)基因设计8对特异性引物,对原生质体单核化得到的2个不同极性的杏鲍菇样本进行PCR扩增。[结果]4个信息素基因和3个信息素受体基因仅能在A2B2极性中存在,而在A1B1极性中不存在。[结论]用B交配型位点基因能对杏鲍菇不同极性进行鉴定,且这7个基因可以作为杏鲍菇原生质体单核化极性快速鉴定的SCAR分子标记。     

田头菇属不同分离菌株杂交研究

目的:验证杨柳田头菇菌株YAASM0711的性遗传模式,探索田头菇属不同分离菌株间的杂交结果.方法:对菌株YAASM0962、YAASM0969以及茶树菇CS45做了交配型与种间杂交研究.结果:菌株YAASM0962其性遗传模式为四极异宗结合,4种交配型比例A3B3∶A4B3∶A3B4∶A4B4为6∶10∶14∶7;菌株YAASM0969和茶树菇CS45出现偏分离现象,只有两种极性出现,2种交配型比例分别为(YAASM0969,A5B5∶A6B6)38∶35和(CS45,A7B7∶A8B8)51∶55.菌株YAASM0711与YAASM0962、YAASM0969、YAASM0967、CS45之间杂交能形成具锁状联合的双核菌丝,且除茶树菇外均能产生子实体.结论:除茶树菇CS45外其余的菌株为杨柳田头菇,它们的有性繁殖方式应该均为四极异宗结合,伴随人工的栽培,其交配因子基因之间不断的重组、插入或删除引发偏分离现象,导致极性菌株比例失调,甚至使一些极性丢失.     

香菇自然群体中个体间的空间分布及其遗传联系

应用体细胞不亲和性反应、交配型因子分析和基因组DNA的RAPD分析,研究了一个分布于方圆约1km的6根倒木上的18个香菇野生菌株间的遗传差异。结果表明,该群体大多数菌株间配对（80．4％）体细胞不亲和,而同一倒木菌株间配对的体细胞亲和率达62．5％。不同倒木菌株间未发现体细胞亲和的配对。该群体存在11个特异的A因子和7个特异的B因子。同一倒木的菌株有的交配型因子相同,有的则不同。不同倒木的菌株大多数交配型因子不同,未发现交配型因子完全相同的菌株。RAPD分析显示,体细胞亲和的菌株,交配型因子完全相同的菌株,在基于DNA相似系数的遗传相关聚类中,首先聚为小类。总起来看,在自然群体中,香菇个体间的遗传差异与其空间分布之间存在一定的联系,随着空间距离的增大,菌株间的异质性相应增高。     

草菇子代单孢菌株的菌落类型与A因子分布规律研究

根据菌株在培养皿中的生长情况,草菇V23的124个单孢分离菌株可分为气生型和匍匐型两大类,气生型菌株为44株,匍匐型菌株为80株。根据草菇A因子相关特异性分子标记,PCR验证单孢萌发菌株的A因子中的A1、A2分子标记的分布情况,探讨了A因子与不同菌落形态的相关性。试验结果表明:124株菌株中,同核体101株,异核体为23株,所占比例分别为81.45%和18.55%。气生型的草菇单孢菌株A1因子为20株,占气生型菌株比例为45.45%,气生型的草菇单孢菌株A2因子为15株,其比例为34.09%;匍匐型的草菇单孢菌株A1因子为15株,占匍匐型菌株比例为18.75%,匍匐型的草菇菌株A2因子为51株,其比例为63.75%,未能发现A因子与菌落形态之间的明显相关性。选用不同A因子,不同菌落表型的草菇菌株相互交配,经PCR筛选,获得20株真正的杂交菌株,杂交菌株的菌落形态气生型与匍匐型占的比例为1:1。表明只要气生型菌丝参与杂交,其杂交菌株的菌落形态则是以气生型为主;匍匐型与匍匐型杂交后的菌丝也不全是气生型,而是以匍匐型为优势群体。选取8株杂交菌株进行岀菇,只有1株产生子实体。     

香菇交配型因子次级重组体的鉴定

对13个香菇菌株的担孢子后代进行了交配型分析,其中8个菌株非亲和反应与亲和反应之比与预期的3∶1的比例无显著差异。另外5个菌株非亲和反应与亲和反应之比不符合3∶1,其中4个菌株在0.05显著水平的X2值仅略高于理论值,而另一菌株HL01具有特殊的表现,其单核体132个随机配对的非亲和反应与亲和反应之比为82∶50,X2值显著偏离3∶1的临界值。用4个标准测试菌株鉴定了来自HL01同一子实体的189个孢子单核体的交配型,在189个单核体中,161个单核体归于4种正常交配型(A1B1,A2B2,A1B2,A2B1)之一。而另外28个可能源于次级重组的单核体可分成另外4个类群。通过以所有可能的组合进行配对杂交,进一步分析了28个单核体的交配型。结果表明,次级重组同时在A因子和B因子中发生,重组值分别为8.5%和11.6%。A因子至少由2个亚基组成而B因子可能由不止2个亚基组成。随后的出菇试验表明,至少含有1个重组体的所有可亲和配对均具有结实能力。     

杨柳田头菇交配型因子与菌丝生长速度关系

以杨柳田头菇（Agrocybe salicacola）菌株711子实体为材料,经担孢子弹射,用稀释分离法获得224个单孢菌株,其中单核菌株210个,交配试验及单孢出菇证明其性遗传模式为四极异宗结合,4种交配型的比例为AxBx∶AxBy∶AyBx∶AyBy为47∶59∶53∶51。研究结果还表明,杨柳田头菇4种交配型的数量、比例与单孢萌发速度、生长速度相关,生长速度较慢的菌株基本上属于一种交配型,只有少数生长慢的菌株属于另外两种交配型。值得注意的是,尽管快（F）-慢（S）配对的异核体与快（F）-快（F）配对的异核体在YPD平板上生长速度无明显差别,但在聚丙烯栽培袋上F-S异核体的生长速度明显快于F-F异核体,这说明交配因子A和B与生长速度基因可能连锁,且存在重组现象,F-S交配的异核体在生长上有优势,可能是人工选择后交配因子亚基减少导致偏分离发生的原因。     

Population structure and mycelial phenotypic variability of the ectomycorrhizal basidiomycete Laccaria bicolor (Maire) Orton

Mating type allele distribution and phenotypic variability were investigated in field populations of Laccaria bicolor. Sporophores associated with Norway spruce (Picea abies), colonized by natural sources of inoculum and growing in a seed orchard, were sampled to obtain dikaryotic strains and assay their phenotypic variability for traits important to the symbiosis. Basid-iospores were also collected for mating type analysis of different mycelia. Four sporophore mating types were identified containing seven A and five B factors. Out-breeding efficiency was estimated at 73.8% and the population was slightly inbred. Crosses with previously characterized L. bicolor strains from two nearby populations identified in total six sporophore mating types and ten A and nine B factors, for an estimated outbreeding efficiency (85.7%) similar to previous studies of more spatially disparate Laccaria spp. populations. Dikaryotic strains were tested for mycelial growth rate, as a measure of their competitive ability, on agar media containing a soluble (NaH₂PO₄), or an insoluble (CaHPO₄) phosphate source. Their ability to solubilize the latter was also tested to assess their relative capacity to access insoluble, inorganic phosphate. In most cases, significant variation was detected among strains from the same site for all variables. On three sites (VC4, VC5 and VC7), each determined previously to possess a uniform mycelial genotype, phenotypic variability was likely due to epigenetic variation among different strains of the same genotype. Possible evidence for dikaryon-monokaryon crosses was observed in vivo on one sample site (VC2) where adjacent mycelia shared two mating factors. The phenotypic variability of different mycelial genotypes reflected their genetic variability observed as mating type allele diversity and underlined the importance of basidiospore dispersal in introducing new genotypes into the population. The reproductive strategies of L. bicolor are discussed and compared to those of other basidiomycete species.     

香菇自然群体中个体间的空间分布及其遗传联系*

应用体细胞不亲和性反应、交配型因子分析和基因组ＤＮＡ的ＲＡＰＤ分析,研究了一个分布于方圆约１ｋｍ的６根倒木上的１８个香菇野生菌株间的遗传差异。结果表明,该群体大多数菌株间配对（８０．４％）体细胞不亲和,而同一倒木菌株间配对的体细胞亲和率达 ６２．５％。不同倒木菌株间未发现体细胞亲和的配对。该群体存在 １１个特异的Ａ因子和７个特异的Ｂ因子。同一倒木的菌株有的交配型因子相同,有的则不同。不同倒木的菌株大多数交配型因子不同,未发现交配型因子完全相同的菌株。ＲＡＰＤ分析显示,体细胞亲和的菌株,交配型因子完全相同的菌株,在基于ＤＮＡ相似系数的遗传相关聚类中,首先聚为小类。总起来看,在自然群体中,香菇个体间的遗传差异与其空间分布之间存在一定的联系,随着空间距离的增大,菌株间的异质性相应增高。     

Fusarium subglutinans f. sp. Pini represents a distinct mating population in the gibberella fujikuroi species complex

Fusarium strains in the Gibberella fujikuroi species complex cause diseases on a variety of economically important plants. One of these diseases, pitch canker of Pinus spp., is caused by strains identified as Fusarium subglutinans f. sp. pini. Fertile crosses were detected between F. subglutinans f. sp. pini strains from South Africa, California, and Florida. F. subglutinans f. sp. pini strains were not cross-fertile with the standard tester strains of six of the seven other mating populations of G. fujikuroi. Sporadic perithecia with ascospores were obtained in two crosses with the mating population B tester strains. These perithecia were homothallic, and the ascospores derived from these perithecia were vegetatively compatible with the mating population B tester strain parent. We concluded that fertile F. subglutinans f. sp. pini isolates represent a new mating population (mating population H) of G. fujikuroi and that they belong to a unique biological species in a distinct taxon.     

Cellulase activity of Polyporus betulinus

Methods are described for isolating and crossing monocaryons of P. betulinus and of determining their cellulase activity by observing changes in viscosity of a carboxy-methyl cellulose preparation. Cellulase activity, so measured, is not correlated with growth rate in the presence or absence of cellulose. Cellulase activity is almost certainly controlled polygenically and is inherited independently of mating type.     

Mating Type Switching in the Tetrapolar Basidiomycete Agrocybe Aegerita

The study of fruiting in the basidiomycete Agrocybe aegerita has shown that some haploid homokaryotic strains can spontaneously switch their mating specificities at the two unlinked A and B mating type factors. This event causes the dikaryotisation of primary homokaryons without plasmogamy and leads to the differentiation of sporulating fruit-bodies (pseudo-homokaryotic fruiting). For each mating type factor, the genetic analyses have revealed that: (1) parental and switched mating types segregate meiotically as Mendelian markers, (2) a total of six switched mating type factors (two parental and four nonparental) were obtained from a wild strain, (3) most of the nonparental factors have specificities differing from those of a large series of wild factors, (4) strains with the same expressed mating type can generate different specificities, (5) switching is always restricted to the same mating type in a homokaryon, (6) nonparental types can switch again, and (7) meiosis fixes the specificities to which switching can occur. This suggests, for the first time in filamentous fungi, the existence of a mechanism analogous to the mating type switching in yeasts. We hypothese that both A and B mating type regions in A. aegerita are constituted of three loci, one specialized in expression and two other carrying silent information. Mating type switching in homokaryotic strains would occur by copy transposition of silent A and B information into the expression loci. Moreover, we propose that during meiosis the silent loci are substituted by copies of the expressed loci.     

The Species Problem in a Ciliate with a High Multiple Mating Type System, Euplotes crassus

ABSTRACT. One hundred twenty non-autogamous wild-type strains of Euplotes crassus , collected over seven years, mainly from the Mediterranean coasts, were investigated for their mating interactions. The strains were mixed pair-wise and data from mating reactions were evaluated and organized by means of a specially constructed computer program. The program identified 38 strains with distinctive mating patterns which could be clustered in nine clumps, all of which were connected either directly or indirectly. Thus, all these strains appeared to be components of the same gene pool, even though direct genetic exchange between strains was not possible in every combination. Subsequently, the 38 strains were subjected to cytometric analysis and scored for zymic variations resulting from electrophoretic patterns of five enzyme systems (acid phosphatases, amylases, malic dehydrogenase, malic enzyme, and tetrazolium oxidases) of proved diagnostic value in the identification of Euplotes species. No significant discontinuities correlated with mating patterns was apparent from these analyses. It was concluded that the E. crassus strains analyzed are not properly divided in sibling species and it was consistently suggested to avoid a genetic partitioning of ciliate species endowed with high multiple mating type systems, in which the sets of wild strains brought under investigation with difficulty represent the natural dimensions of the species.     

不同交配型马尔尼菲篮状菌的抗真菌药物敏感性

马尔尼菲篮状菌是马尔尼菲篮状菌病的致病菌,具有不同交配型,且交配型分布具有地域差异。交配型是影响某些真菌药物敏感性的因素之一,但是否影响马尔尼菲篮状菌的药物敏感性不详。为了解马尔尼菲篮状菌交配型和其药物敏感性的关系,本研究检测了不同交配型马尔尼菲篮状菌对7种抗真菌药物的敏感性。结果显示,与MAT-1型马尔尼菲篮状菌相比,MAT-2型马尔尼菲篮状菌对伊曲康唑的敏感性较低,提示马尔尼菲篮状菌交配型可能与马尔尼菲唑类耐药相关。