Taxonomy and pathogenicity of Leptographium species associated with Ips subelongatus infestations of Larix spp. in northern China, including two new species

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• 作者：Xue-Wei Liu ; Hui-Min Wang ; Quan Lu ; Cony Decock ; Yong-Xia Li…
• 关键词：DNA multilocus ; Leptographium innermongolicum ; Leptographium taigense ; Leptographium zhangii
• 刊名：Mycological Progress
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：16
• 期：1
• 页码：1-13
• 全文大小：
• 刊物主题：Plant Sciences; Ecology; Microbiology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1861-8952
• 卷排序：16

文摘

The larch bark beetle (Ips subelongatus), which occurs in larch plantations over a vast area of eastern Asia, infects both dying and fallen trees. When its population reaches a high density, the beetle may also infect healthy trees, resulting in tree decline and, eventually, death. Leptographium spp., in both their sexual and asexual states, are mainly associated with conifer-infesting bark beetles; some species are important tree pathogens. The aims of this study were to identify the Leptographium spp. associated with I. subelongatus infestations of Larix spp. in northern China and to examine their pathogenicity towards the tree. Morphological studies and phylogenetic approaches based on multilocus DNA sequence data (ITS2- partial r28S, partial β-tubulin, and EF-1α gene regions) showed that three Leptographium species occur in association with I. subelongatus in the areas investigated: Leptographium taigense, which is recorded in China for the first time, and two new species, namely L. innermongolicum sp. nov. and L. zhangii sp. nov. Leptographium innermongolicum is closely related to L. taigense, whereas L. zhangii belongs to the Grosmannia piceaperda species complex. The pathogenicity of these Leptographium species towards mature Larix spp. was tested by stem inoculation in forests. All inoculations only resulted in small lesions on the inner bark; therefore, the three Leptographium species were not considered to be pathogenic.