Evolutionary Ecology of Marine Yeasts as Determined by Molecular Relatedness

对海洋微生物在生物地球化学循环和其他过程中的作用的认识相当缺乏。这在一定程度上是由于对这些海洋生物的基本生物学知识不足。分子生物学的最新进展为解答各种基本问题提供了工具。本研究将探讨海洋酵母的起源和系统发育关系。初步调查表明，海洋酵母起源于陆生植物寄生虫，即异酸菌，该菌群包括锈菌和黑穗病等真菌。最近的研究表明，异担子菌能够产生自由活的酵母菌阶段，这些酵母菌可能通过翅膀或陆地排水分布。我们基于表型特征的研究表明，许多海洋酵母是从植物寄生虫的酵母阶段进化而来的，或者与植物寄生虫的酵母阶段相同。然而，基于核DNA亲缘关系的分子研究表明，基于表型反应的比较可能会产生误导，因为许多这些标准的遗传基础只存在于少数基因中。我们建议通过分子亲缘关系的研究来确定海洋酵母菌种间的关系以及酵母菌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.