Kang S, Chumley F G, Valent B
DuPont Company, Wilmington, Delaware 19880-0402.
Genetics. 1994 Oct;138(2):289-96. doi: 10.1093/genetics/138.2.289.
Using genomic subtraction, we isolated the mating-type genes (Mat1-1 and Mat1-2) of the rice blast fungus, Magnaporthe grisea. Transformation of M. grisea strains of one mating type with a linearized cosmid clone carrying the opposite mating-type gene resulted in many "dual maters," strains that contain both mating-type genes and successfully mate with Mat1-1 and Mat1-2 testers. Dual maters differed in the frequency of production of perithecia in pure culture. Ascospores isolated from these homothallic crosses were either Mat1-1 or Mat1-2, but there were no dual maters. Most conidia from dual maters also had one or the other of the mating-type genes, but not both. Thus, dual maters appear to lose one of the mating-type genes during vegetative growth. The incidence of self-mating in dual maters appears to depend on the co-occurrence of strains with each mating type in vegetative cultures. In rare transformants, the incoming sequences had replaced the resident mating-type gene. Nearly isogenic pairs produced from three M. grisea laboratory strains were mated to investigate their fertility. One transformant with switched mating type appears to have a mutation that impairs the development of asci when its mating partner has a similar genetic background. The M. grisea Mat1-1 and Mat1-2 genes are idiomorphs approximately 2.5 and 3.5 kb in length, respectively.
利用基因组消减技术，我们分离出了稻瘟病菌（Magnaporthe grisea）的交配型基因（Mat1-1和Mat1-2）。用携带相反交配型基因的线性化粘粒克隆转化一种交配型的稻瘟病菌株，产生了许多“双交配型菌株”，即含有两种交配型基因并能成功与Mat1-1和Mat1-2测试菌株交配的菌株。双交配型菌株在纯培养中产生子囊壳的频率有所不同。从这些同宗配合杂交中分离出的子囊孢子要么是Mat1-1型，要么是Mat1-2型，但没有双交配型的。双交配型菌株产生的大多数分生孢子也只含有一种交配型基因，而非两种都有。因此，双交配型菌株似乎在营养生长过程中丢失了其中一种交配型基因。双交配型菌株中自交的发生率似乎取决于营养培养中每种交配型菌株的同时存在。在极少数转化体中，导入的序列取代了原有的交配型基因。由三个稻瘟病菌实验室菌株产生的近等基因对进行了交配，以研究它们的育性。一个交配型发生转换的转化体，当它的交配伙伴具有相似的遗传背景时，似乎有一种突变会损害子囊的发育。稻瘟病菌的Mat1-1和Mat1-2基因是特异型基因，长度分别约为2.5 kb和3.5 kb。
