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

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.亨蒂霉属（Huntiella，Microascales目）属于子囊菌类群，该属真菌全球广布，可在多种木本植物上定殖。目前，学界对于中国境内该属真菌的物种界定、多样性、起源及生态影响尚缺乏深入了解。近期，研究团队从中国南部广东、广西、福建及海南四省的人工林新伐桉树（Eucalyptus）的伐桩或植株伤口处，分离得到亨蒂霉属菌株。另有部分菌株分离自海南省桉树人工林周边的台湾相思（Acacia confusa）伐桩。本研究旨在明确这些亨蒂霉属菌株的物种分类，并测试其对桉树幼苗的致病性。通过形态学观察与核核糖体DNA内部转录间隔区（ITS1-5.8S-ITS2 = ITS）、部分β微管蛋白（BT1）基因及翻译延伸因子1α（TEF1α）的多基因系统发育分析，本研究发现了9个此前未被报道的亨蒂霉属新物种，其中8株分离自桉树，1株分离自台湾相思。研究明确了这些新物种的交配型：其中7个为异宗配合型，1个为同宗配合型，剩余1个为单性生殖型（仅携带MAT1-2-1基因）。致病性测试结果显示，这9个亨蒂霉属物种均可在桉树幼苗上形成病斑，且病斑面积显著大于对照组的机械损伤伤口。本研究为厘清中国南部地区亨蒂霉属真菌的分布格局、物种多样性及致病性提供了基础依据。