Elevated Sporulation Efficiency in Fission Yeast Schizosaccharomyces japonicus Strains Isolated from Drosophila.

Taisuke Seike,Chikara Furusawa,Fumio Matsuda,Natsue Sakata

doi:10.3390/jof7050350

Abstract

The fission yeast Schizosaccharomyces japonicus, comprising S. japonicus var. japonicus and S. japonicus var. versatilis varieties, has unique characteristics such as striking hyphal growth not seen in other Schizosaccharomyces species; however, information on its diversity and evolution, in particular mating and sporulation, remains limited. Here we compared the growth and mating phenotypes of 17 wild strains of S. japonicus, including eight S. japonicus var. japonicus strains newly isolated from an insect (Drosophila). Unlike existing wild strains isolated from fruits/plants, the strains isolated from Drosophila sporulated at high frequency even under nitrogen-abundant conditions. In addition, one of the strains from Drosophila was stained by iodine vapor, although the type strain of S. japonicus var. japonicus is not stained. Sequence analysis further showed that the nucleotide and amino acid sequences of pheromone-related genes have diversified among the eight strains from Drosophila, suggesting crossing between S. japonicus cells of different genetic backgrounds occurs frequently in this insect. Much of yeast ecology remains unclear, but our findings suggest that insects such as Drosophila might be a good niche for mating and sporulation, and will provide a basis for the understanding of sporulation mechanisms via signal transduction, as well as the ecology and evolution of yeast.

Highlights

The fission yeast Schizosaccharomyces japonicus, which was first isolated from strawberries at a farm of Kyusyu University in Japan [1], is a close relative of the well-studied model organism Schizosaccharomyces pombe [2]
Because fruit flies feed on immobile yeast and are known to accumulate yeast and bacteria in their crop [1], we attempted to isolate novel S. japonicus strains from Drosophila
We isolated eight strains from fruit flies sampled at two distinct locations in Japan, indicating that the fission yeast S. japonicus species may live symbiotically in Drosophila

Summary

Introduction

The fission yeast Schizosaccharomyces japonicus, which was first isolated from strawberries at a farm of Kyusyu University in Japan [1], is a close relative of the well-studied model organism Schizosaccharomyces pombe [2]. Hyphal growth of S. japonicus is triggered by environmental stresses as nutritional starvation [8,9,10] and DNA damage [11] This response is thought to enable hyphae cells of S. japonicus to escape more quickly from harmful stimuli. S. japonicus has unique physiological features such as semi-open mitosis [4], light response [12], and growth via fermentation under anaerobic conditions [13]. Despite these interesting properties, relatively few studies on S. japonicus have been reported to date

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Conclusion