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

球孢子虫是一种形态特征，由母细胞在雄蕊顶端形成，成熟后排出。在包括蘑菇和担子菌酵母在内的真菌的现有分类中，形成球孢子的活性一直被用作属水平的分类标准，但由于大量形成球孢子和非球孢子形成种的系统发育研究，人们对此提出了质疑。在这项研究中，用一株形成气球分生孢子的酵母菌Bullera oryzae JCM 5281进行了气球分生孢子形成的分子生物学研究。从JCM 5281出发，通过反复培养，获得了产孢子活性降低的突变株。从水稻大斑病菌JCM 5281及其突变体中提取总RNA，经基因图像分析试剂盒差异显示，突变株JCM 5281与突变体JCM 5281的mRNA图谱不同。然而，参与气球分生孢子形成的基因是…在本实验中，由于突变株在-80℃条件下保存后活性恢复，因此建议不删除，而是全部或部分抑制其表达。重新考察了球孢子形成的条件，发现琼脂中的水分影响了球孢子形成的强度。采用抑制性消减杂交方法，对气囊分生孢子形成条件(保存在实验室工作台上的培养基数)和不形成气球分生孢子的条件(保存在塑料容器内、盖上盖子的培养基数)进行了比较，分析了195个克隆。为了探索一种新的区分物种的标准，迄今报道的各种数据考察了最近重新分类的白色隐球菌复合体和劳伦蒂隐球菌复合体，以及报道了种内多样性的乳链霉菌。同工酶图谱被认为有助于区分物种间或物种内的多样性。较少

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