title: Antifungal activity of borrelidin produced by a Streptomyces strain isolated from soybean.
abstract: In this study, an endophytic  Streptomyces  sp. neau-D50 with strong antifungal activity against  Phytophthora sojae  was isolated from healthy soybean root, using an in vitro screening technique. A bioactivity-guided approach was then employed to isolate and determine the chemical identity of bioactive constituents with antifungal activity from strain neau-D50. The structure of the antifungal metabolite was elucidated as borrelidin on the basis of spectral analysis. To our knowledge, this is the first report that borrelidin has strong antifungal activity against dominant race 1 of  P. sojae  with EC(50) and EC(95) of 0.0056 and 0.026 mg/L, respectively. The values were respectively 62.5- and 262.3-fold lower than those of the commercial fungicide metalaxyl, which has been used to treat soybean seed for the control of  P. sojae . The in situ bioassays demonstrated that borrelidin at 10 mg/L reduced  P. sojae  race 1 lesions on soybean seedlings by 94.72% without affecting root growth. Thus, borrelidin might be a promising candidate for new antifungal agents against  P. sojae.
authors.affiliation: School of Life Science, Northeast Agricultural University, Harbin, PR China.
authors.forename: Chong-Xi
authors.initials: CX
authors.lastname: Liu
authors.forename: Ji
authors.initials: J
authors.lastname: Zhang
authors.forename: Xiang-Jing
authors.initials: XJ
authors.lastname: Wang
authors.forename: Ping-Ting
authors.initials: PT
authors.lastname: Qian
authors.forename: Ji-Dong
authors.initials: JD
authors.lastname: Wang
authors.forename: Ya-Mei
authors.initials: YM
authors.lastname: Gao
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Yan
authors.forename: Shu-Zhen
authors.initials: SZ
authors.lastname: Zhang
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Xu
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Li
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Xiang
mesh_terms: D000935:Antifungal Agents / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D005233:Fatty Alcohols / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D010838:Phytophthora / Q000187:drug effects; D013025:Glycine max / Q000382:microbiology*; D013302:Streptomyces / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D005233:Fatty Alcohols; C005066:borrelidin