Mating Behaviour and Vegetative Compatibility in Spanish Populations of Botryotinia fuckeliana

Mating behaviour and vegetative compatibility were studied in Spanish populations of Botryotinia fuckeliana. Fifty-seven isolates out of the 61 tested were sexually fertile with one or more of the reference strains of known mating type (MAT1-1 or MAT1-2). Thirty-nine isolates were heterothallic, giving fertile crosses when mated with the MAT1-1 (24 isolates) or the MAT1-2 (15 isolates) reference strain. Eighteen isolates crossed successfully with both MAT1-1 and MAT1-2 reference strains, and were referred to as homothallic or MAT1-1/2. Both mating types were widespread, being represented in isolates from two regions, from the same and different greenhouses, from different hosts, and from different years of isolation. Isolates were paired on Malt Extract Agar + NaCl to evaluate vegetative compatibility. Most of the paired isolates were unable to fuse and showed a different reaction of incompatibility. Nitrate-non-utilising (nit) mutants were selected by growth on a medium amended with 30–50gl^–1 potassium chlorate. Over 600 chlorate-resistant sectors were recovered from 40 isolates at a mean frequency of 0.15–2.39 sectors per colony, but only 11% were identified as nit mutants by their thin growth with no aerial mycelium on minimal medium. However, most of these nit mutants reverted to wild type during six months of storage on chlorate-amended medium. Genetic complementation between nit mutants occurred only in two cases between mutants from the same isolate.     

小麦条锈菌异核作用产生的一新菌系

在小麦条锈菌黄色和白色夏孢子菌系混合繁殖的群体中,筛选出一新的白化菌系。新菌系在鉴别寄主上的反应型明显不同于两原始菌系,其夏孢子芽管的多核率较原始菌系高,这些结果表明该新菌系是经异核作用产生的。本研究还发现,新苗系的多核率随继代转接而下降,但其毒性不变。     

淡紫拟青霉种内异核现象的初步研究

研究了淡紫拟青霉的不同田间分离菌株单孢子后代的异核现象。结果表明,来源于福建、江苏、安徽的4个菌株(19,20,459,641)的单孢子培养后代,在PPDA+1%活性炭的培养基上进行配接试验,仅在19和459 2个菌株间能形成异核体,其频率为12.25%;在配接试验中,2个亲和菌落交界处长出致密的菌丝簇组成的实线,可推测为异核体。从来自菌丝簇线的每个单菌丝尖端培养物中分离出30个以上的单孢子,将其分别移接到PDA平板上,将来源于单孢子的菌落与2个亲本菌落进行比较,有3个菌丝尖端培养物(459-8×19-2,459-7×19-10,459-6×19-1)重现了两亲本类型或出现了新的菌落类型,异核现象得到证实。     

Use of nitrate non-utilising (Nit) mutants to determine vegetative compatibility in Botryotinia fuckeliana (Botrytis cinerea)

Nitrate non-utilising (Nit) mutants of six field strains and three single-ascospore strains of Botryotinia fuckeliana were selected by plating mycelial plugs onto a nitrate-containing minimal medium amended with chlorate. Mutants were characterised by growth responses on minimal medium amended with various sole nitrogen sources. For each parental strain two mutants were produced: nit1, defective in nitrate reductase apoenzyme; and NitM, defective in the molybdenum cofactor pathway. Complementation on nitrate minimal medium was observed between nit1 and NitM mutants from the same parent in all instances. However, complementation was not observed between any such combinations when the mutants were derived from different parents. It is concluded that a vegetative incompatibility system operates in B. fuckeliana resulting in multiple vegetative compatibility groups. One of the single-ascospore strains was derived from a cross between two of the field strains, indicating that new compatibility groups can be generated during sexual reproduction. Mycelial interaction zones were formed between all parental strains when they were paired on NaCl-amended medium, indicating congruence between mycelial incompatibility and vegetative incompatibility.     

不产子实体蛹虫草单孢子分离株的获得及RAPD分析

对优势蛹虫草原始菌株WWM04进行单孢子分离,共获得9个单孢子分离株,采用米饭培养基培养确证并且获得6个完全不产子实体的单孢子分离株。利用随机扩增多态性DNA(RAPD)分子标记方法对菌落差异的4个菌落特征典型的不产子实体单孢子分离株(SSP2、SSP7、SSP19和SSP21)、原始菌株以及由原始菌株12次转接后退化的菌株进行遗传多样性分析。结果表明,引物S37、S61对6个菌株的扩增谱带具有非常明显的特异性,该结果为蛹虫草退化分子标记奠定基础,并且在一定程度上也印证了蛹虫草异核现象和准性生殖理论。     

葡萄霜霉菌异核现象对致病力表现的作用

对取自法国不同地区的葡萄霜霉菌群体的孢子囊的观察表明,该菌致病力的差异首先表现在其孢子囊的大小和其中所含有的细胞核数量的差异。通过连续孢子囊移种,由任意取自自然群体的一个孢子囊获得了几个致病力各异的纯系。致病力不同的纯系混合侵染,可提高混合群体的致病力,利用对 Metalaxyl的抗性作标记,证明了不同菌丝体间的细胞核交换现象和异核现象。由于异核现象的作用,霜霉菌的自然群体的致病力可以通过细胞核之间的协生作用达到其最高水平。