In the bipolar basidiomycete Pholiota nameko, a pair of homeodomain protein genes located at the A mating-type locus regulates mating compatibility. In the present study, we used a DNA-mediated transformation system in P. nameko to investigate the homeodomain proteins that control the clamp formation. When a single homeodomain protein gene (A3- hox1 or A3-hox2) from the A3 monokaryon strain was introduced into the A4 monokaryon strain, the transformants produced many pseudo-clamps but very few clamps. When two homeodomain protein genes (A3-hox1 and A3-hox2) were transformed either separately or together into the A4 monokaryon, the ratio of clamps to the clamp-like cells in the transformants was significantly increased to approximately 50%. We, therefore, concluded that the gene dosage of homeodomain protein genes is important for clamp formation. When the sip promoter was connected to the coding region of A3-hox1 and A3-hox2 and the fused fragments were introduced into NGW19-6 (A4), the transformants achieved more than 85% clamp formation and exhibited two nuclei per cell, similar to the dikaryon (NGW12 -163 × NGW19-6). The results of real-time RT-PCR confirmed that sip promoter activity is greater than that of the native promoter of homeodomain protein genes in P. nameko. So, we concluded that nearly 100% clamp formation requires high expression levels of homeodomain protein genes and that altered expression of the A mating-type genes alone is sufficient to drive true clamp formation.

맛버섯의 우량균주를 선발하고 병재배에 적합한 환경조건과 재배기술을 찾고자 시험한 결과는 다음과 같다. 맛버섯 균사는 MCM배지와 Hamada배지에서 잘 자랐고, 배지의 적정산도는 pH6~7이었다. 균사생육에 가장 적합한 온도는 25℃였으며, 15℃ 이하와 30℃ 이상의 조건에서는 균사생육이 현저하게 늦어졌다. 맛버섯 균주 29계통 중 생산성이 좋은 계통은 JNM19007, JNM19026, JNM19027과 JNM19028이었다. 자실체 생산을 위하여 가장 적합한 배지조성비는 미송톱밥 80%와 밀기울 20%(V/V) 혼합배지로 1,100cc 병당 평균 188g의 자실체가 생산되었다. 최적 후배양기간은 50일 이었으며, 균긁기 후 7일 만에 발이 되었다. 발이유기동안 적정 온도는 12℃이었고, 생육기에는 16℃였다. 맛버섯 전 재배기간 동안 적합한 상대습도는 95%였다.