杨柳田头菇担孢子交配型偏分离成因研究

Analysis of Distorted Segregation of Mating Types Ratio of Basidiospores in Agrocybe salicacola

以8个杨柳田头菇菌株为材料,用统计学方法分析了担孢子单核体的各类交配型比例。结果表明,不同菌株都存在一定的偏分离现象但程度不同,12.5%的菌株担孢子交配型不呈预期的比例;单孢挑取时间过短会导致一些菌株极性的丢失,多数菌株其亲本型孢子多于重组型孢子的趋势,若将生长速度极慢单孢菌株排除在统计之外,发生偏分离的菌株占供试菌株的25%,在各菌株4种交配型中,除菌株Y2外,菌株Y1也发生严重的偏分离现象(χ2=47.40),菌株Y1亲本型出现了处理前没有的偏分离现象(χ2=38.19),整个群体亲本型和重组型的担孢子分布偏分离程度加重,而Y1自交后代因挑取的单孢数量相对少(37～75个单孢菌株)并未发生偏分离现象。因此,挑取时间作为一个人为因素会导致生长速度极慢的菌株丢失,而表现出虚假的偏分离现象,所以担子菌的交配型偏分离应该是孢子萌发力或生长速度导致的结果,而不是孢子比例差别的结果。

The statistical analysis of the mating type ratios of basidiospores from 8 strains of Agrocybe salicacola were carried out.The results showed that distortion degrees of segregation of different strains were obviously different.12.5 % tested strains did not have a expected segregation ratio of basidiospores.The time for picking up single spore colony could affect the mating type ratio,and some spore colonies with low germination capability or low-growth rate may be lost.These single spores with a very slow growth rate were ignored in data analysis,and 25 % tested strains did not have expected segregation ratio of basidiospores.Strain Y1（χ2=47.40） had a obvious distortion segregation as strain Y2.The distortion segregation phenomenon of parental type of strain Y1（χ2=38.19）was newly emersion,basidiospores distribution of all the parental types and recombinant types had more severe distortion degree of segregation.However,the distortion segregation did not happen in the single spore isolations from self-fertilizing strains of Y1 when fewer single spore colonies were isolated（37-75）.Isolating time as a contrived factor could result in omitting some single spore isolation and pseudo-distortion segregation degree of mating types of basidiospores from A.salicacola could happen.Therefore,the distortion segregation of mating types of basidiomycete may be the result of lower germination capability or lower growth rate of basidiospores rather than the proportion of spores with different mating types.