Nine novel species of Huntiella from southern China with three distinct mating strategies and variable levels of pathogenicity

ABSTRACT

The ascomycete genus Huntiella (Microascales) has a cosmopolitan distribution and occurs on a wide range of woody plants. Little is known regarding the identity, diversity, origin, or impact of these fungi in China. Recently, isolates of Huntiella spp. were collected from stumps of freshly felled trees or wounds on plantation-grown Eucalyptus in Guangdong, Guangxi, Fujian, and Hainan provinces of southern China. Additional isolates were obtained from stumps of Acacia confusa near Eucalyptus plantations in Hainan Province. The aim of this study was to identify these Huntiella species and to test their pathogenicity on Eucalyptus seedlings. Morphology and multigene phylogenies of the nuclear rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) region and partial β-tubulin (BT1) and translation elongation factor 1α (TEF1α) genes revealed nine previously unknown Huntiella species, eight from Eucalyptus and one from A. confusa. The mating types of these species were determined, showing that seven are heterothallic, one is homothallic, and one is unisexual (MAT1-2-1 gene). Pathogenicity tests showed that the nine Huntiella species can produce lesions on Eucalyptus seedlings, larger than wounds caused by controls on these plants. This study provides a basic understanding of the distribution, diversity, and pathogenicity of Huntiella species in southern China.

KEYWORDS:

• Ceratocystidaceae
• Ceratocystis moniliformis complex
• phylogeny
• plantation forestry
• 9 new taxa

ACKNOWLEDGMENTS

We thank the University of Pretoria and China Eucalypt Research Centre (CERC) for facilities and equipment to undertake this work.

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Funding

This study was supported by the National Natural Science Foundation of China (NSFC) (project no. 31622019), the National Key R&D Program of China (project no. 2016YFD0600505), and the International Science & Technology Cooperation Program of China (project no. 2012DFG31830). We acknowledge members of the Tree Protection Cooperative Programme (TPCP) and the National Research Foundation (NRF), South Africa, for financial support.