Abstract:
The Cryphonectriaceae is a highly diverse group of fungi that are mainly parasites and endophytes with a few saprophytic species. Chrysoporthe and allied taxa are devastating tree pathogens especially of Myrtales (Myrtaceae and Melastomataceae). Every new region particularly tropical and sub-tropical areas of the world where trees in the Myrtales are examined for fungi in the Cryphonectriaceae seem to reveal previously unknown species of these fungi. Thus, description of new species is aided by molecular data using DNA sequence comparison combined with morphological characteristics.
The first chapter of this dissertation deals with a review of the major topics related to the Cryphonectriaceae. These include their taxonomic diversity, origin, identification tools, host jumps and shifts. It also summarizes the general approaches to working with fungi in the Cryphonectriaceae such as techniques for isolation and preservation. The Cryphonectriaceae represent a hugely diverse group of fungi with several new species only being discovered recently. Many areas where the hosts of these fungi grow are relatively under-explored and several species have yet to be adequately studied.
In the second chapter of this dissertation, a new genus and species Myrtonectria myrtacearum (prov. nom.) and two species of Celoporthe including C. borbonica (prov. nom.) and C. tibouchinae (prov. nom.) were described from native Myrtales in La R�union and South Africa. Description of the new taxa was based on multi-gene sequence comparisons and morphological characteristics. Pathogenicity trials showed that the new taxa were mildly pathogenic to Eucalyptus (TAG 5) clone after 6 weeks of greenhouse inoculation trials.
