Ophiostoma tsotsi sp. nov., A Wound-infesting Fungus of Hardwood Trees in Africa

Abstract

Polymorphic sequence-characterised marker assays from a recent diversity study on the Ascomycete fungus Ophiostoma quercus reported that some isolates from Africa were genetically distinct from O. quercus. In the present study, these African isolates were compared with authentic O. quercus isolates by evaluating morphological characters, growth in culture, mating compatibility and DNA sequence data. The isolates from Africa were morphologically similar to O. quercus, presenting Pesotum and Sporothrix synanamorphs in culture. Phylogenetic analyses of the ribosomal internal transcribed spacer regions 1 and 2, b-tubulin and translation elongation factor 1-a gene regions confirmed that the African group represents a distinct species within the hardwood lineage of the O. piceae complex, closely related to O. ulmi and O. himalulmi. Mating studies between O. quercus and the African isolates showed that isolates mated predominantly with those of their own group, although there were rare cases of fertile crosses between the groups. Isolates residing in the African lineage are described here as a new species, O. tsotsi sp. nov.

Ophiostomatoid fungi associated with mangroves in South Africa, including Ophiostoma palustre sp. nov.

“…Similarly, Yin et al (2016) distinguished between the O. ulmi complex and a newly defined O. piceae complex that includes only conifer-associated fungi. Grobbelaar et al (2010) showed that BT and EF sequences are needed in addition to ITS to resolve species level questions in the O. ulmi complex. Our analyses of these three gene regions (Fig.…”

“…Although the O. ulmi complex includes Ophiostoma ulmi and O. novo-ulmi, the causal agents of the Dutch elm disease (Brasier 1991), most species in the complex, including O. tsotsi, are known as non-pathogenic sapstain fungi on hardwood trees De Beer et al 2003;Grobbelaar et al 2010). Inoculation studies with O. tsotsi on young…”

The Ophiostoma clavatum species complex: a newly defined group in the Ophiostomatales including three novel taxa

“…In an attempt to obtain sexual structures for morphological descriptions of species revealed by the phylogenetic analyses, crosses between different isolates of the same species were made in all possible combinations on Petri dishes to which autoclaved host tree twigs had been added (Grobbelaar et al (2010). To serve as controls, isolates were inoculated individually on Petri dishes.…”

Taxonomy and phylogeny of the Leptographium procerum complex, including Leptographium sinense sp. nov. and Leptographium longiconidiophorum sp. nov.

“…Isolates of opposite mating type of the same species were paired with each other in all possible combinations. These pairings were done on water agar with sterilized pieces of pine wood using the technique described by Grobbelaar et al (2010), and incubated for 3-4 months at 25°C. Interspecific crosses were also performed using isolates of four morphologically indistinguishable species (L. bhutanense, L. sinoprocerum, L. gracile and L. latens).…”