Li Yan, Jeewon Rajesh, Hyde Kevin D, Mo Ming-He, Zhang Ke-Qin
Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, Yunnan Province, PR China.
Mycol Res. 2006 Jul;110(Pt 7):790-800. doi: 10.1016/j.mycres.2006.04.011.
Two new nematode-trapping fungi, Dactylellina sichuanensis and D. varietas from China, which capture nematodes by both adhesive knobs and non-constricting rings, are described and illustrated. D. sichuanensis is characterized by both adhesive knobs and non-constricting rings, solitary conidiophores and 3-(4)-6 septate conidia, as compared with species such as D. appendiculata, D. candida, D. leptospora and D. lysipaga. Although D. sichuanensis shares similar types of trapping devices, the presence of simple conidiophores and spindle-shaped conidia with these species, it can be distinguished by its larger conidia and presence of more than four septa. In D. sichuanensis, a single conidium is born at the tip of conidiophore, while in D. candida, 3-10 conidia are born near the apex of conidiophore in a capitate arrangement. It produces spindle-shaped conidia with 3-6 septa, whereas D. leptospora produces cylindrical-shaped conidia with 5-15 septa. D. appendiculata captures nematodes by adhesive knobs whereas D. sichuanensis captures nematodes by both adhesive knobs and non-constricting rings. They also differ in conidial size (35-82.5mum in D. sichuanensis as compared with 57-108mum in D. appendiculata). D. varietas is characterized by conidiophores that are branched at right-angles, and elongate to fusoid conidia, with 7-8 septa (more than 25% of which are curved). D. varietas resembles D. asthenopaga, Dactylella oxyspora and Monacrosporium multiseptatum, but has elongate-fusoid conidia, whereas D. asthenopaga possesses obconical or clavate conidia. D. varietas forms both adhesive knobs and non-constricting rings whereas Dactylella oxyspora does not produce any trapping device. M. multiseptatum differs from D. varietas in having larger conidia with an inflated middle cell. Phylogenetic analyses based on nuclear and protein coding DNA sequences (18 S, and a combined 28 S+5.8 S+beta-tubulin dataset) indicate that these two taxa should be assigned to the family Orbiliaceae.
本文描述并阐释了两种来自中国的新的捕食线虫真菌，即四川隔指孢（Dactylellina sichuanensis）和变异隔指孢（D. varietas），它们通过粘性瘤和非收缩环来捕获线虫。与附枝隔指孢（D. appendiculata）、白色隔指孢（D. candida）、细孢隔指孢（D. leptospora）和缢缩隔指孢（D. lysipaga）等物种相比，四川隔指孢的特征在于具有粘性瘤和非收缩环、单生分生孢子梗以及3-（4）-6隔膜的分生孢子。尽管四川隔指孢与这些物种具有相似类型的捕食器官，以及简单的分生孢子梗和纺锤形分生孢子，但它可以通过更大的分生孢子和超过四个隔膜来区分。在四川隔指孢中，单个分生孢子生于分生孢子梗顶端，而在白色隔指孢中，3-10个分生孢子以头状排列生于分生孢子梗顶端附近。它产生具3-6个隔膜的纺锤形分生孢子，而细孢隔指孢产生具5-15个隔膜的圆柱形分生孢子。附枝隔指孢通过粘性瘤捕获线虫，而四川隔指孢通过粘性瘤和非收缩环捕获线虫。它们在分生孢子大小上也有所不同（四川隔指孢为35-82.5μm，而附枝隔指孢为57-108μm）。变异隔指孢的特征是分生孢子梗直角分枝，以及细长至梭形的分生孢子，具7-8个隔膜（其中超过25%为弯曲隔膜）。变异隔指孢与虚弱隔指孢（D. asthenopaga）、尖孢隔指孢（Dactylella oxyspora）和多隔单顶孢（Monacrosporium multiseptatum）相似，但具有细长梭形分生孢子，而虚弱隔指孢具有倒圆锥形或棒状分生孢子。变异隔指孢形成粘性瘤和非收缩环，而尖孢隔指孢不产生任何捕食器官。多隔单顶孢与变异隔指孢的不同之处在于其分生孢子更大，中间细胞膨大。基于核DNA和蛋白质编码DNA序列（18 S，以及28 S + 5.8 S +β-微管蛋白联合数据集）的系统发育分析表明，这两个分类单元应归入圆盘菌科（Orbiliaceae）。
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