Novel species of Celoporthe from Eucalyptus and Syzygium trees in China and Indonesia

Abstract

Many species in the Cryphonectriaceae cause diseases of trees, including those in the genera Eucalyptus and Syzygium. During disease surveys on these trees in southern China, fruiting structures typical of fungi in the Cryphonectriaceae and associated with dying branches and stems were observed. Morphological comparisons suggested that these fungi were distinct from the well known Chrysoporthe deuterocubensis, also found on these trees in China. The aim of this study was to identify these fungi and evaluate their pathogenicity to Eucalyptus clones/species as well as Syzygium cumini. Three morphologically similar fungal isolates collected previously from Indonesia also were included in the study. Isolates were characterized based on comparisons of morphology and DNA sequence data for the partial LSU and ITS nuclear ribosomal DNA, β-tubulin and TEF-1α gene regions. After glasshouse trials to select virulent isolates field inoculations were undertaken to screen different commercial Eucalyptus clones/species and S. cumini trees for susceptibility to infection. Phylogenetic analyses showed that the Chinese isolates and those from Indonesia reside in a clade close to previously identified South African Celoporthe isolates. Based on morphology and DNA sequence comparisons, four new Celoporthe spp. were identified and they are described as C. syzygii, C. eucalypti, C. guangdongensis and C. indonesiensis. Field inoculations indicated that the three Chinese Celoporthe spp., C. syzygii, C. eucalypti and C. guangdongensis, are pathogenic to all tested Eucalyptus and S. cumini trees. Significant differences in the susceptibility of the inoculated Eucalyptus clones/species suggest that it will be possible to select disease-tolerant planting stock for forestry operations in the future.

• Cryphonectriaceae
• Myrtales
• plantation forestry
• southeastern Asia
• stem canker pathogens

ACKNOWLEDGMENTS

This study was initiated through the bilateral agreement between South Africa and China, and financially supported through projects 2007DFA31190, 2008B050100014 and 10145624536-400000.

We also appreciate the financial and logistical support of the members of Tree Protection Co-operative Programme (TPCP) and Dr Treena I. Burgess (Murdoch University, Australia) for providing some isolates used in this study. We are grateful for the help of Prof Hennie Groeneveld and Dr Mike van der Linde who assisted with the statistical analyses, Dr Hugh Glen who provided the Latin description, Miss Marcele Vermeulen for the TEF-1α sequence data for Celoporthe dispersa, and colleagues of LeiZhou Forestry Bureau, XinTao Mou, GuiXiang Zhao and ChunYan Xie for their valuable assistance in the field.