Ustilago violacea sporidia of the white (w) MAD strain (a‐2 w lys‐3 ino‐1 thi) incubated on minimal medium containing 100 mM KClO3 (potassium chlorate) produced only colonies with the pink phenotype. Sporidia from these colonies retained their pink color on complex medium. Sporidia of the diploid D1 strain (a‐1 y nic‐1 thi/a‐2 w met‐1 arg‐f Chl70 thi) and of the diploid D2 strain (a‐1 y his‐1 glu‐1 thi/a‐2 w lys‐3 ino‐1 thi) produced pink colonies on complex medium. Streaks of diploid D1 sporidia from the pink colonies were stable on complex medium. In contrast, streaks of diploid D2 sporidia, which are heterozygous for the MAD strain, were unstable, initially producing pink colonies on complex medium but then, with continued incubation, producing white termini. Sporidia from the white termini with diploid morphology continued to yield white colonies. Teliospore colonies from three crosses with the MAD strain as a common parent were uniformly pink or had a pink sector instead of the expected uniformly white colonies or colonies having a white sector. Four of 20 and 13 of 20 teliospore colonies, respectively, from two of the three crosses had both a‐1 and a‐2 sporidia, and the remaining colonies had only a‐1 or only a‐2 sporidia. All 40 teliospore colonies from the third cross had only a‐1 or only a‐2 sporidia. All of these observations indicated that the MAD strain may have two autonomous, transactive transposable elements in different chromosomes and that insertional mutations in at least two haplolethal loci were responsible for the teliospore colonies with only a‐1 or only a‐2 mating type. Crossing over between a haplolethal locus and the centromere would account for teliospore colonies with both a‐1 and a‐2 sporidia.

中文翻译：

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紫花黑粉病的遗传学。三十五。单倍体和二倍体孢子的转座和萌发的冬孢子

在含有 100 mM KClO3（氯酸钾）的基本培养基上培养的白色 (w) MAD 菌株 (a-2 w lys-3 ino-1 thi) 的黑粉病孢子菌仅产生具有粉红色表型的菌落。来自这些菌落的孢子在复杂培养基上保持其粉红色。二倍体 D1 菌株（a-1 y nic-1 thi/a-2 w met-1 arg-f Chl70 thi）和二倍体 D2 菌株（a-1 y his-1 glu-1 thi/a-）的孢子2 w lys-3 ino-1 thi) 在复杂培养基上产生粉红色菌落。来自粉红色菌落的二倍体 D1 孢子条纹在复杂培养基上是稳定的。相比之下，杂合的 MAD 菌株的二倍体 D2 孢子的条纹不稳定，最初在复杂培养基上产生粉红色菌落，但随后继续孵育，产生白色末端。来自具有二倍体形态的白色末端的孢子继续产生白色菌落。来自以 MAD 菌株作为共同亲本的三个杂交的冬孢子菌落呈均匀粉红色或具有粉红色扇区，而不是预期的均匀白色菌落或具有白色扇区的菌落。三个杂交中的两个分别有 20 个冬孢子菌落中的 4 个和 13 个同时具有 a-1 和 a-2 孢子，其余菌落只有 a-1 或只有 a-2 孢子。来自第三次杂交的所有 40 个冬孢子菌落只有 a-1 或只有 a-2 孢子。所有这些观察结果表明，MAD 菌株可能在不同的染色体中具有两个自主的、反式激活的转座元件，并且至少有两个单致死位点的插入突变是导致只有 a-1 或只有 a-2 交配型的冬孢子菌落的原因。