title: Induction of trap formation in nematode-trapping fungi by a bacterium.
abstract: Three soil bacterial strains were identified as Chryseobacterium sp. TFB on the basis of their 16S rRNA gene sequences. Conidia of Arthrobotrys oligospora produced a few mycelial traps (MT) and conidial traps (CT) when cultured with bacterial cells that they did not produce when cultured with a bacterial cell-free culture filtrate. However, co-culture of A. oligospora with bacterial cells and bacteria-free filtrate simultaneously induced MT and CT in large amounts. With the increased concentration of bacteria-free filtrate, the number of typical CT increased, but conidial germination was progressively inhibited. Scanning electron microscopy of A. oligospora co-cultured with bacteria revealed that bacterial attachment to hyphae was a prerequisite to trap formation and that bacteria-free filtrate facilitated bacterial attachments to hyphae. The results that the addition of nutrients in co-culture medium decreased the number of traps suggest that this type of trap formation may be favoured at a low nutrient status. Eight fungi tested were able to form MT and CT when co-cultured with bacterial cells and bacteria-free culture filtrate, but the abilities varied among species. This study provides novel evidence that under laboratory conditions, soil bacteria attaching to hyphae could induce traps in nematode-trapping fungi.
authors: Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China.
authors: Lei
authors: L
authors: Li
authors: Mingchuan
authors: M
authors: Ma
authors: Yongjun
authors: Y
authors: Liu
authors: Jingwei
authors: J
authors: Zhou
authors: Qing
authors: Q
authors: Qu
authors: Kaiping
authors: K
authors: Lu
authors: Denggao
authors: D
authors: Fu
authors: KeQin
authors: K
authors: Zhang
mesh_terms: D000818:Animals; D001203:Ascomycota / Q000502:physiology*; D045247:Chryseobacterium / Q000145:classification / Q000235:genetics / Q000502:physiology*; D018920:Coculture Techniques; D025301:Hyphae / Q000648:ultrastructure; D009348:Nematoda / Q000382:microbiology; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S