35 - Issatchenkia Kudryavtsev emend. Kurtzman, Smiley & Johnson

Abstract

This chapter focuses on Issatchenkia genus and its constituent species. Asexual reproduction in this genus occurs through multilateral budding on a narrow base. Its cells are spheroidal, ellipsoidal or elongate, and pseudohyphae are present. The asci are unconjugated when formed from diploid cells or may be conjugated if formed by the pairing of complementary mating types. They are persistent and form 1–4roughened spheroidal ascospores. The protuberances causing ascospore roughness may not be visible under the light microscope. The constituent species of this genus include Issatchenkia occidentalis, Issatchenkia orientalis, Issatchenkia scutulata, and Issatchenkia terricola. The asci in Issatchenkia occidentalis are unconjugated, persistent, and form one or two roughened ascospores. Electron microscopy may be required to discern the protuberances on spore walls and isolation of single spores demonstrated this species to be heterothallic. Issatchenkia scutulata has two varieties: Issatchenkia scutulata and Issatchenkia scutulata var. exigua. The asci in this species are persistent, unconjugated, and usually form four spheroidal, roughened spores in diamond-shaped tetrads. This species is heterothallic and four-spored asci give two spores of each mating type.