Chrysoporthe puriensis sp. nov. from Tibouchina spp. in Brazil: an emerging threat to Eucalyptus

Abstract

The discovery of Cryphonectriaceae and more specifically species related to the Eucalyptus canker pathogen Chrysoporthe cubensis on shrubs and trees in the Melastomataceae, has deepened our understanding of relevant, and potentially globally threatening tree pathogens. Recent isolations of Cryphonectriaceae associated with cankers on Tibouchina spp. in Brazil gave rise to an apparently undescribed species of Chrysoporthe associated with stem and branch cankers that lead to tree death. Cultures of this fungus were subjected to phylogenetic studies based on sequences for the ITS and β-tubulin gene regions. These analyses revealed a novel taxon that is described here as Chrysoporthe puriensis sp. nov., having both sexual and asexual states. Pathogenicity tests on two species of Tibouchina (T. granulosa, T. heteromalla) and hybrids of Eucalyptus grandis x E. urophylla showed that Chr. puriensis can infect and cause disease on all of these trees. It is clearly not only damaging on native Tibouchina spp. where environmental conditions are conducive to disease development, but also potentially threatening to non-native Eucalyptus spp., which form the basis of a major plantation forest industry.