Department of Entomology, Michigan State University, East Lansing, Michigan 48823, USA.
Escuela de Ciencias Biológicas, Pontifica Universidad Católica del Ecuador, Quito, Ecuador, 17-01-2184.
Mycologia. 2022 May-Jun;114(3):487-500. doi: 10.1080/00275514.2022.2065441. Epub 2022 May 24.
Ambrosia beetles from the scolytine tribe Xyleborini (Curculionidae) are important to the decomposition of woody plant material on every continent except Antarctica. These insects farm fungi on the walls of tunnels they build inside recently dead trees and rely on the fungi for nutrition during all stages of their lives. Such ambrosia fungi rely on the beetles to provide appropriate substrates and environmental conditions for growth. A small minority of xyleborine ambrosia beetle-fungal partnerships cause significant damage to healthy trees. The xyleborine beetle vectors a (Hypocreales) fungus that is lethal to balsa ( (Malvaceae)) trees in Ecuador. Although this pathogenic fungus and its associated beetle are not known to be established in the United States, several other non-native ambrosia beetle species are vectors of destructive plant diseases in this country. This fact and the acceleration of trade between South America and the United States demonstrate the importance of understanding fungal plant pathogens before they escape their native ranges. Here we identify the fungi accompanying ambrosia beetles collected in Ecuador. Classification based ribosomal internal transcribed spacer 1 (ITS) sequences revealed the most prevalent fungi associated with are sp. and sp. (Microascales: Microascaceae), which have been confirmed as ambrosia fungi for xyleborine ambrosia beetles, and sp. (Hypocreales), which is a diverse genus found abundantly in soils and associated with plants. Phylogenetic analyses of the strains based on ITS, translation elongation factor (), and two subunits of the DNA-directed RNA polymerase II ( and ) identified them as sp. AF-9 in the Ambrosia Clade (AFC). This species was previously associated with a few xyleborine ambrosia beetles, most notably the species complex (Eichhoff 1868) (Curculionidae: Scolytinae: Xyleborini). Examination of ITS and sequences showed a close affinity between the isolated from spp. and other xyleborine-associated as well as the soil fungus . This characterization of ambrosia fungi through DNA sequencing confirms the identity of a putative plant pathogen spread by beetles and expands the documented range of and ambrosia fungi.
除南极洲外，鞘翅目扁甲科（Coleoptera）的长蠹科（Xyleborini）拟步甲在各大洲分解木质植物材料都非常重要。这些昆虫在其在刚死亡的树木内部建造的隧道壁上种植真菌，并在其生命的所有阶段都依靠真菌获取营养。此类共生真菌依赖扁甲科昆虫为其生长提供适当的基质和环境条件。一小部分长蠹科拟步甲共生真菌会对健康树木造成严重损害。在厄瓜多尔，长蠹科扁甲携带一种（Hypocreales）真菌，这种真菌对轻木（Malvaceae）树是致命的。尽管这种致病真菌及其相关的扁甲尚未在美国确立，但该国还有其他几种非本地的拟步甲共生真菌是破坏性植物疾病的载体。这一事实以及南美洲与美国之间贸易的加速，表明在真菌植物病原体逃离其自然范围之前，了解它们是非常重要的。在这里，我们确定了在厄瓜多尔收集的拟步甲共生真菌。基于核糖体内部转录间隔区 1（ITS）序列的分类揭示了与共生真菌最相关的是 属的 种和 种（Microascales：Microascaceae），它们已被确认为长蠹科拟步甲共生真菌，以及 种（Hypocreales），这是一种在土壤中丰富存在并与植物相关的多样属。基于 ITS、翻译延伸因子（）和 DNA 指导的 RNA 聚合酶 II 的两个亚基（和）的菌株系统发育分析，将这些菌株鉴定为 Ambrosia 属 AFC 中的 种 AF-9。该种先前与少数几种长蠹科拟步甲共生，最显著的是 种复合体（Eichhoff 1868）（鞘翅目：象甲科：长蠹科）。ITS 和 序列的检查表明，从 种分离出的 与其他与长蠹共生的 以及土壤真菌 具有密切的亲缘关系。通过 DNA 测序对共生真菌的特征描述，确认了由拟步甲传播的潜在植物病原体的身份，并扩展了记录的 与 共生真菌的范围。
