Lilleskov Erik A, Bruns Thomas D
Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, California 94720, USA.
Mycologia. 2005 Jul-Aug;97(4):762-9. doi: 10.3852/mycologia.97.4.762.
Patterns of fungal spore dispersal affect gene flow, population structure and fungal community structure. Many Basidiomycota produce resupinate (crust-like) basidiocarps buried in the soil. Although spores are actively discharged, they often do not appear to be well positioned for aerial dispersal. We investigated the potential spore dispersal mechanisms of one exemplar of this growth form, Tomentella sublilacina. It is a widespread ectomycorrhizal fungus that sporulates in the soil organic horizon, can establish from the spore bank shortly after disturbance, but also can be a dominant species in mature forest stands. We investigated whether its spores could be dispersed via spore-based food webs. We examined external surfaces, gut contents and feces from arthropod fungivores (mites, springtails, millipedes, beetles, fly larvae) and arthropod and vertebrate predators (centipedes, salamanders) from on and around T. sublilacina sporocarps. Spore densities were high in the guts of many individuals from all fungivore groups. Centipede gut contents, centipede feces and salamander feces contained undigested invertebrate exoskeletons and many apparently intact spores. DAPI staining of spores from feces of fungivores indicated that 7-73% of spores contained intact nuclei, whereas spores from predators had lower percentages of intact nuclei. The spiny spores often were lodged on invertebrate exoskeletons. To test the viability of spores that had passed through invertebrate guts we used fecal droppings of the millipede Harpaphe haydeniana to successfully inoculate seedlings of Pinus muricata (Bishop pine). These results indicate the potential for T. sublilacina spore dispersal via invertebrates and their predators in soil food webs and might help to explain the widespread distribution of this species. It is likely that this is a general mechanism of dispersal for fungi producing resupinate sporocarps, indicating a need to develop a fuller understanding of the linkages of soil food webs and spore dispersal.
真菌孢子传播模式影响基因流动、种群结构和真菌群落结构。许多担子菌产生埋于土壤中的平伏（壳状）子实体。尽管孢子会主动释放，但它们似乎通常不利于进行空中传播。我们研究了这种生长形式的一个典型代表——浅紫丝膜菌（Tomentella sublilacina）潜在的孢子传播机制。它是一种广泛分布的外生菌根真菌，在土壤有机层中产生孢子，在干扰后不久能从孢子库中定殖，同时也可能是成熟林分中的优势物种。我们研究了其孢子是否能通过基于孢子的食物网进行传播。我们检查了浅紫丝膜菌子实体及其周围的节肢动物食真菌者（螨、跳虫、千足虫、甲虫、蝇幼虫）以及节肢动物和脊椎动物捕食者（蜈蚣、蝾螈）的体表、肠道内容物和粪便。所有食真菌者群体中许多个体的肠道内孢子密度都很高。蜈蚣的肠道内容物、蜈蚣粪便和蝾螈粪便中含有未消化的无脊椎动物外骨骼以及许多明显完整的孢子。对食真菌者粪便中的孢子进行DAPI染色表明，7% - 73%的孢子含有完整的细胞核，而捕食者粪便中的孢子完整细胞核的比例较低。有刺的孢子常常附着在无脊椎动物的外骨骼上。为了测试通过无脊椎动物肠道的孢子的活力，我们使用千足虫哈氏糙足千足虫（Harpaphe haydeniana）的粪便成功接种了滨海松（Pinus muricata，主教松）的幼苗。这些结果表明浅紫丝膜菌的孢子有可能通过土壤食物网中的无脊椎动物及其捕食者进行传播，这可能有助于解释该物种的广泛分布。很可能这是产生平伏子实体的真菌的一种普遍传播机制，这表明有必要更全面地了解土壤食物网与孢子传播之间的联系。
