Shull V, Hamer J E
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA.
Fungal Genet Biol. 1996 Mar;20(1):59-69. doi: 10.1006/fgbi.1996.0010.
Repetitive DNA sequences genetically differentiate certain host-specific forms of the plant pathogenic fungus Pyricularia grisea. For example, high copy numbers of a sequence designated MGR586 are conserved in isolates that infect rice. In this report, we describe the molecular characterization of another repetitive DNA sequence designated fosbury. Restriction mapping and DNA sequence analysis show that fosbury is a member of a long terminalrepeat (LTR)-containing retrotransposon family, and gel blot hybridization analysis suggests that, like MGR586, fosbury is preferentially found in isolates that infect rice. This supports the view that rice pathogens comprise a genetically distinct form of P. grisea. We also investigated the distribution of fosbury and MGR586 and found that these elements are sometimes associated in the genome, and gel blot hybridization analysis shows that restriction sites flanking both of these elements resolve rice pathogens into similar clonal lineage groups. We conclude that the transposition of repetitive DNA sequences plays an important role in generating DNA fingerprint variation in the rice blast fungus.
重复DNA序列在遗传上区分了植物致病真菌稻瘟病菌的某些宿主特异性形式。例如，在感染水稻的分离株中，一个名为MGR586的序列的高拷贝数是保守的。在本报告中，我们描述了另一个名为fosbury的重复DNA序列的分子特征。限制性图谱分析和DNA序列分析表明，fosbury是一个含有长末端重复序列（LTR）的逆转座子家族的成员，凝胶印迹杂交分析表明，与MGR586一样，fosbury优先存在于感染水稻的分离株中。这支持了水稻病原体构成稻瘟病菌一个遗传上不同形式的观点。我们还研究了fosbury和MGR586的分布，发现这些元件有时在基因组中相关联，凝胶印迹杂交分析表明，这两个元件两侧的限制性位点将水稻病原体解析为相似的克隆谱系组。我们得出结论，重复DNA序列的转座在稻瘟病菌DNA指纹变异的产生中起重要作用。
