Evolutionary Ecology of Marine Yeasts as Determined by Molecular Relatedness

人们对海洋微生物在生物地球化学循环等过程中的作用知之甚少。这在一定程度上是由于对这些海洋生物的基础生物学信息不足。分子生物学的最新进展使回答各种基本问题的工具成为可能。这项研究将考察海洋酵母的起源和系统发育关系。初步调查表明，海洋酵母菌起源于陆生植物寄生虫异杆菌，包括锈菌和黑穗病等真菌。最近的研究表明，异源担子菌能够产生自由生活的酵母菌阶段，这些阶段可以通过翼或陆地排水来分布。我们的研究基于表型特征，表明许多海洋酵母是从植物寄生虫的酵母阶段进化而来的，或者与之相同。然而，基于核DNA相关性的分子研究表明，基于表型反应的比较可能具有误导性，因为许多标准的遗传基础只存在于少数几个基因中。我们建议通过分子关联性的研究来确定海洋酵母的种类之间的关系以及酵母与陆生植物寄生虫的关系。

There is a considerable lack of knowledge of the role of marine microorganisms is biogeochemical cycling and other processes. This is due, in part, to inadequate information on the fundamental biology of these marine organisms. Recent advances in molecular biology have made tools available to answer a variety of basic questions. This research will examine the origin and phylogenetic relationships among marine yeasts. Preliminary investigations indicate that marine yeasts originated from terrestrial plant parasites, the heterobacidiomycetes, a group that includes such fungi as the rusts and smuts. Recent studies have shown that the heterobasidiomycetes are capable of producing free living yeasts stages that may be distributed by wing or land drainage. Our studies, based on phenotypic characteristics, suggests that many of the marine yeasts are evolved from, or are identical to, the yeasts stages of the plant parasites. However, molecular studies, based on nuclear DNA relatedness, have shown that comparisons based on phenotypic responses can be misleading because the genetic bases for many of thes criteria reside in only a few genes. We propose to determine the relationships between species of marine yeasts and the relationships of yeasts to terrestrial plant parasites through studies of molecular relatedness.