A molecular approach to exploring and evaluating novel criteria for fungal taxonomy

球形分生孢子是一种形态特征，由母细胞在柱头顶端形成，成熟后排出体外。球形分生孢子的形成活性在目前的真菌分类中被用作属水平的分类标准，包括蘑菇和担子菌酵母，但由于对球形分生孢子和非球形分生孢子的大量系统发育研究而受到质疑。在这项研究中，利用形成球孢分生孢子的酵母米芽孢酵母JCM 5281，采用分子方法来阐明球孢分生孢子的形成。对JCM 5281进行重复培养，获得了球孢子形成活性降低的突变体。利用基因图像试剂盒进行差异显示，获得稻瘟病菌JCM 5281及其突变体的总rna，发现JCM 5281的mRNA模式与突变体不同。然而，参与球孢分生孢子形成的基因在本实验中被认为没有被删除，而是全部或部分表达被抑制，因为突变体在-80℃保存后恢复了活性。重新考察了球状分生孢子形成的条件，发现球状分生孢子的形成强度受琼脂培养基含水量的影响。将形成球形分生孢子条件（实验室工作台上的培养基）与未形成球形分生孢子条件（盖紧盖子的塑料容器中保存的培养基）进行抑制减法杂交，分析195个无性系。球孢子的形成活性有待进一步研究。在寻找一种新的物种区分标准方面，目前已有的各种资料研究了最近重新分类的隐球菌（Cryptococcus albidus）复合体和C.laurentii复合体，以及已报道的种内多样性的pyricola Udeinomyces。同工酶模式被认为对物种间或物种内多样性的区分是有用的。少

Ballistoconidium, which is made on the tip of the sterigma from the mother cell and discharged when it matures, is a morphological characteristic. Ballistoconidium-forming activity has been employed as a taxonomic criterion of the generic level in the present taxonomy of fungi including mushrooms and basidiomycetous yeasts, but is questioned as a result of numerous phylogenetic studies of ballistoconidium-forming and non-ballistoconidium-forming species. In this study, a molecular approach to the elucidation of the ballistoconidium formation has been made using a ballistoconidium-forming yeast Bullera oryzae JCM 5281. From JCM 5281,its ballistoconidium-forming activity decreased mutants were obtained by a repetitive cultivation. When total RNAs were obtained from Bullera oryzae JCM 5281 and its mutants, the mRNA patterns of JCM 5281 were different from those of mutants by the differential display using Gene image kit. However, the genes involved in the ballistoconidium-formation were a … More ssumed not to be deleted but all or part of their expression suppressed in this experiment, because the activity of the mutant was recovered after being stored at -80℃.The condition for ballisitoconidium formation was reexamined and the strength of the ballistoconidium-formation was found to be affected by the water content of agar media. Suppression subtraction hybridization between the ballistoconidium-forming condition (media kept on a workbench in the laboratory) and the condition under which ballistoconidium not formed (media kept in a plastic container covered tightly with a lid) was performed, and 195 clones were analyzed. Further study is necessary to discuss the ballistoconidium-forming activity.Concerning the exploration of a novel criterion to discriminate among species, various data so far reported examined the genus Cryptococcus albidus complex and C.laurentii complex that were reclassified recently, and Udeinomyces pyricola, which the intra-species diversity was reported. Isozyme patterns were thought to be useful for differentiating inter or intra-species diversity. Less