Ballistospore-forming yeasts found on the surface of the Japanese rice plant, Oryza sativa L.

Abstract

Ninety-nine strains of ballistospore-forming yeasts were isolated from 43 samples of dead leaves and stems of the Japanese rice plant (Oryza sativa L.), and identified as belonging to the genera Bullera, Sporobolomyces, and Tilletiopsis. Thirty-one strains out of 55 of Bullera were assigned to B. alba (15 strains), B. crocea (13 strains), and B. piricola (3 strains). The remaining 24 strains of this genus were divided into 6 groups (species) which could not be assigned to any hitherto known species. Thirty-nine strains out of 41 of Sporobolomyces were assigned to S. roseus (35 strains) and S. shibatarrus (4 strains). The remaining 2 strains of this genus were divided into 2 groups (species) which could not be assigned to any hitherto described species. Three strains of Tilletiopsis were assigned to T. lilacina. Of the 8 undescribed species, two were described respectively as the new species, B. oryzae and S. subbrunneus. Strains JCM 5281 and JCM 5278 respectively were designated as the types of the two species. Further study of the remaining 6 undescribed species is required before we determine their taxonomic position. The frequency of isolation of ballistosporeforming yeasts from Oryza sativa L. was 86°c. Sporobolomyces roseus was found in the highest frequency, 72 %, followed by Bullera sp. 1 (35 %), B. crocea (300) , and B. alba (28 %). The remaining species were found in relatively low frequencies below 9 %. Ballistospore-forming yeasts are known as one of the most common yeasts. They are often found on the surface of various kinds of plants. Since the description of Torula shibatana and Pseudomonilia rubicundula by OKUNUKI (1), several investigations of the classification and distribution of these yeasts have been carried out in Japan (2-5). YAMASAKI and Full (2) described 5 new species of ballistospore-forming yeasts; 4 in Sporobolomyces and 1 in Bu//era. However, three of these Sporobolomyces species were re-identified as known species (6) and the culture of Bullera (B. stramina) was lost. Sporobolomyces coralliformis (4) 457

Studies on ballistospore-forming yeasts from the dead leaves of Miscanthus sinensis with descriptions of the new species Sporobolomyces miscanthi, Sporobolomyces subroseus, and Sporobolomyces weijmanii.

“…Yeasts were isolated by the ballistospore-fall method as described in a previous paper (1). The YM agar (Difco Labs) plates used in the isolation were replaced by new ones every day to diminish the disturbance by filamentous fungi and to recover the slowly growing yeasts.…”

“…Ballistospore-forming yeasts were found on 86% of the samples examined and were considered to be common inhabitants of this plant. Further, seven new species of ballistospore-forming yeasts were described based on the isolates from Oryza sativa (1)(2)(3)(4). This suggests that a number of undescribed species of ballistosporeforming yeasts are living in natural conditions, especially on the surface of plant materials.…”

Sporobolomyces griseoflavus and Sporobolomyces sasicola, two new species of ballistosporous yeasts isolated from dead leaves of Sasa sp. in Japan.

“…collected on Suga-daira, Nagano Pref., by Dr. G. Okada, in May 1985. These strains were isolated by the ballistospore-fall method of DERx (1) by using YM agar (Difco Labs) plates as described in the previous paper (2).…”

Ballistosporomyces, a new ballistospore-forming anamorphic yeast genus.

“…This is rarely found in ascomycetous yeasts but sometimes appears in basidiomycetous yeasts (3), especially in ballistospore-forming genera Sporobolomyces and Bensingtonia (27,28,(31)(32)(33)35).…”