三种致病疫霉交配型分子检测方法的比较

致病疫霉Phytophthora infestans属于异宗配合卵菌,当A1、A2两种交配型同时存在时,可以进行有性生殖,产生卵孢子。检测疫霉菌交配型的传统方法是采用对峙培养,这种方法耗时长并且需要标准的A1、A2交配型菌株作为参照。因此,人们希望开发出更加简便和快捷的可直接基于核苷酸序列差异的分子检测方法。目前,已报道了3个与致病疫霉交配型紧密连锁的分子标记可用于交配型的检测。本研究用64株致病疫霉菌比较了3种基于交配型分子标记的检测方法与传统方法检测的结果。结果显示,依据分子标记的3种分子检测方法与传统对峙培养方法测定的交配型结果一致率为61%-73%,而且3种分子检测方法都不能检测出自育菌株。因此,致病疫霉交配型的分子检测方法还有待进一步研究。

Comparison of molecular markers in mating type determination of Phytophthora infestans

Phytophthora infestans is a heterothallic oomycete, which commonly requires two opposite mating types, A1 and A2 to complete sexual reproduction for producing oospores. Conventional method of mating type determination is through pair-culturing the test isolates with A1 and A2 mating type on medium, which is time-consuming and require the standard cultures. Therefore, a simple and fast method based on difference of nucleotide sequence is highly demanding. So far, three molecular markers closely linked to the mating type locus have been reported. In this study, the mating types of 64 isolates of P. infestans are tested by using the molecular methods base on three reported molecular markers for mating types, and the results are compared with those determined by using conventional method. The comparison indicates that the coincidence rate of mating types determined by the three molecular methods and those determined by the conventional method varied from 61% to 73%, and none of the molecular methods could discriminate the self-fertile isolates. Therefore, the molecular method for mating type determination of P. infestans remained to be investigated.