Xylaria is a diverse and ecologically important genus in the Ascomycota. This paper describes the xylariaceous fungi present in an Ecuadorian Amazon Rainforest and investigates the decay potential of selected Xylaria species. Fungi were collected at Yasuní National Park, Ecuador during two collection trips to a single hectare plot divided into a 10-m by 10-m grid, providing 121 collection points. All Xylaria fruiting bodies found within a 1.2-m radius of each grid point were collected. Dried fruiting bodies were used for culturing and the internal transcribed spacer region was sequenced to identify Xylaria samples to species level. Agar microcosms were used to assess the decay potential of three selected species, two unknown species referred to as Xylaria 1 and Xylaria 2 and Xylaria curta, on four different types of wood from trees growing in Ecuador including balsa (Ochroma pyramidale), melina (Gmelina arborea), saman (Samanea saman), and moral (Chlorophora tinctoria). ANOVA and post-hoc comparisons were used to test for differences in biomass lost between wood blocks inoculated with Xylaria and uninoculated control blocks. Scanning electron micrographs of transverse sections of each wood and assay fungus were used to assess the type of degradation present. 210 Xylaria collections were sequenced, with 106 collections belonging to 60 taxa that were unknown species, all with less than 97% match to NCBI reference sequences. Xylaria with sequence matches of 97% or greater included X. aff. comosa (28 isolates), X. cuneata (9 isolates) X. curta and X. oligotoma (7 isolates), and X. apiculta (6 isolates)., All Xylaria species tested were able to cause type 1 or type 2 soft rot degradation in the four wood types and significant biomass loss was observed compared to the uninoculated controls. Balsa and melina woods had the greatest amount of biomass loss, with as much as 60% and 25% lost, respectively, compared to the controls. Xylaria species were found in extraordinary abundance in the Ecuadorian rainforest studied. Our study demonstrated that the Xylaria species tested can cause a soft rot type of wood decay and with the significant amount of biomass loss that occurred within a short incubation time, it indicates these fungi likely play a significant role in nutrient cycling in the Amazonian rainforest.

中文翻译：

---

厄瓜多尔亚马逊地区的不同 Xylaria 及其木材降解模式

Xylaria 是子囊菌门中一个多样化且具有重要生态意义的属。本文描述了厄瓜多尔亚马逊雨林中存在的木聚糖真菌，并研究了选定的木聚糖真菌物种的腐烂潜力。真菌是在厄瓜多尔亚苏尼国家公园进行的两次采集过程中采集的，该采集地点被划分为 10 米 x 10 米的网格，提供 121 个采集点。收集每个网格点 1.2 米半径内发现的所有 Xylaria 子实体。使用干燥的子实体进行培养，并对内部转录间隔区进行测序，以鉴定木霉属样品的物种水平。使用琼脂微环境来评估三种选定物种（两种未知物种，称为 Xylaria 1 和 Xylaria 2 和 Xylaria curta）对厄瓜多尔生长的四种不同类型木材的腐烂潜力，包括轻木 (Ochroma Pyramidale)、梅利纳木 (Gmelina) arborea）、萨曼（Samanea saman）和道德（Chlorophoratinctoria）。使用方差分析和事后比较来测试接种 Xylaria 的木块和未接种的对照木块之间生物量损失的差异。使用每种木材和分析真菌的横截面的扫描电子显微照片来评估存在的降解类型。对 210 个 Xylaria 收藏品进行了测序，其中 106 个收藏品属于 60 个分类群，属于未知物种，所有与 NCBI 参考序列的匹配度均低于 97%。序列匹配度为 97% 或更高的 Xylaria 包括 X. aff。comosa（28 个分离株）、X. cuneata（9 个分离株）、X. curta 和 X.oligotoma（7 个分离株）和 X. apiculta（6 个分离株）。所有测试的 Xylaria 物种均能够引起 1 型或 2 型软腐病与未接种的对照相比，观察到四种木材类型的退化和显着的生物量损失。轻木和梅利纳木的生物量损失最大，与对照相比，损失分别高达 60% 和 25%。在所研究的厄瓜多尔雨林中发现了异常丰富的木霉属物种。我们的研究表明，所测试的 Xylaria 物种可导致软腐型木材腐烂，并且在短时间内发生大量生物量损失，这表明这些真菌可能在亚马逊雨林的养分循环中发挥着重要作用。