Schirawski Jan, Heinze Bernadette, Wagenknecht Martin, Kahmann Regine
Max-Planck-Institut für Terrestrische Mikrobiologie, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
Eukaryot Cell. 2005 Aug;4(8):1317-27. doi: 10.1128/EC.4.8.1317-1327.2005.
Sporisorium reilianum and Ustilago maydis are two closely related smut fungi, which both infect maize but differ fundamentally in their mode of plant invasion and site of symptom development. As a prelude to studying the molecular basis of these differences, we have characterized the mating type loci of S. reilianum. S. reilianum has two unlinked mating type loci, a and b. Genes in both loci and adjacent regions show a high degree of synteny to the corresponding genes of U. maydis. The b locus occurs in at least five alleles and encodes two subunits of a heterodimeric homeodomain transcription factor, while the a locus encodes a pheromone/receptor system. However, in contrast to that of U. maydis, the a locus of S. reilianum exists in three alleles containing two active pheromone genes each. The alleles of the a locus appear to have arisen through recent recombination events within the locus itself. This has created a situation where each pheromone is specific for recognition by only one mating partner.
玉米丝轴黑粉菌和玉蜀黍黑粉菌是两种密切相关的黑粉菌，它们都侵染玉米，但在侵染植物的方式和症状出现的部位上存在根本差异。作为研究这些差异分子基础的前奏，我们对玉米丝轴黑粉菌的交配型位点进行了表征。玉米丝轴黑粉菌有两个不连锁的交配型位点，a和b。两个位点及其相邻区域的基因与玉蜀黍黑粉菌的相应基因具有高度的共线性。b位点至少有五个等位基因，编码一种异源二聚体同源域转录因子的两个亚基，而a位点编码一个信息素/受体系统。然而，与玉蜀黍黑粉菌不同的是，玉米丝轴黑粉菌的a位点存在于三个等位基因中，每个等位基因包含两个活性信息素基因。a位点的等位基因似乎是通过该位点自身最近的重组事件产生的。这就造成了一种情况，即每种信息素仅对一个交配伙伴的识别具有特异性。
