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加拿大安大略南部,英国、瑞典和美国小麦白粉菌自然种群的田间调查表明该病菌具广泛的遗传变异性。本地种群内这种变异性的原因可能有:1)基因突变,2)从异地传入新的病源接种体,3)毒性基因在有性凡殖期的重组,4)无性重组。尽管无性杂交的作用在其他植物病原真菌中已经被证实,但是在小麦白粉菌生活史中无性重组的作用尚未进行过考查。已知在尖孢镰刀菌蕃茄专化型中有无性遗传交换,在锈菌中也有人提出有无性重组。在大麦白粉菌中未检测出无性重组。本研究之目的在于考察无性重组可否作为一种机制,来解释田间小麦白粉菌种群的某些遗传变异性。
Field surveys of the natural population of powdery mildew in southern Ontario, the United Kingdom, Sweden and the United States revealed extensive genetic variability among the pathogens. The reasons for this variability in local populations may include: 1) gene mutation, 2) introduction of new pathogen inoculum from a different site, 3) recombination of virulence genes during sexual reproduction, 4) clonal recombination. Although the role of cloning has been demonstrated in other plant pathogenic fungi, the role of asexual recombination in the life history of powdery mildew has not been examined. It is known that there is asexual genetic exchange in Fusarium oxysporum tomato, and in Aureus, there is also a suggestion of asexual recombination. Asexual recombination was not detected in B. barley. The purpose of this study was to examine whether asexual recombination can be used as a mechanism to explain some of the genetic variability of wheat powdery mildew in the field.