Ophiostoma gemellus and Sporothrix variecibatus from mites infesting Protea infructescences in South Africa

Abstract

Ophiostoma (Ophiostomatales) represents a large genus of fungi mainly known from associations with bark beetles (Curculionidae: Scolytinae) infesting conifers in the northern hemisphere. Few southern hemisphere native species are known, and the five species that consistently occur in the infructescences of Protea spp. in South Africa are ecologically unusual. Little is known about the vectors of Ophiostoma spp. from Protea infructescences, however recent studies have considered the possible role of insects and mites in the distribution of these exceptional fungi. In this study we describe a new species of Ophiostoma and a new Sporothrix spp. with affinities to Ophiostoma, both initially isolated from mites associated with Protea spp. They are described as Ophiostoma gemellus sp. nov. and Sporothrix variecibatus sp. nov. based on their morphology and comparisons of DNA sequence data of the 28S ribosomal, β-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. DNA sequences of S. variecibatus were identical to those of a Sporothrix isolate obtained from Eucalyptus leaf litter in the same area in which S. variecibatus occurs in Protea infructescences. Results of this study add evidence to the view that mites are the vectors of Ophiostoma spp. that colonize Protea infructescences. They also show that DNA sequence comparisons are likely to reveal additional cryptic species of Ophiostoma in this unusual niche.

• β-tubulin
• ITS
• LSU
• phylogeny
• vector

We thank the National Research Foundation (NRF) and the NRF/DST Centre of Excellence in Tree Health Biotechnology (CTHB) for financial support, as well as colleagues at the Forestry and Agricultural Biotechnology Institute (FABI) and the Centraalbureau voor Schimmelcultures (CBS) for making cultures available for study. We also thank the Western Cape Nature Conservation Board for issuing the necessary collecting permits. Dr Walter Gams (CBS) is acknowledged for providing the Latin diagnoses.