title: Bacteria can mobilize nematode-trapping fungi to kill nematodes.
abstract: In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode-predatory form; this predacious form is characterized by formation of specialized cellular structures or 'traps'. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator-prey interactions in prey defense mechanisms.
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Guo-Hong
authors.initials: GH
authors.lastname: Li
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Zou
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Xing-Lai
authors.initials: XL
authors.lastname: Ji
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
authors.forename: Pei-Ji
authors.initials: PJ
authors.lastname: Zhao
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Lian-Ming
authors.initials: LM
authors.lastname: Liang
authors.affiliation: 1] Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China [2] Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Xu
authors.affiliation: Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Texas 77030, USA.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: An
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Yue-Ke
authors.initials: YK
authors.lastname: Qin
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Meng-Qing
authors.initials: MQ
authors.lastname: Tian
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: You-Yao
authors.initials: YY
authors.lastname: Xu
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Ma
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Ze-Fen
authors.initials: ZF
authors.lastname: Yu
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Huang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Shu-Qun
authors.initials: SQ
authors.lastname: Liu
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Niu
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Jin-Kui
authors.initials: JK
authors.lastname: Yang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Ke-Qin
authors.initials: KQ
authors.lastname: Zhang
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D000818:Animals; D000898:Antibiosis; D001203:Ascomycota / Q000502:physiology*; D001419:Bacteria / Q000378:metabolism*; D009348:Nematoda / Q000382:microbiology*; D014508:Urea / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D014508:Urea