title: Lasiodiplodia sp. ME4-2, an endophytic fungus from the floral parts of Viscum coloratum, produces indole-3-carboxylic acid and other aromatic metabolites.
abstract: BACKGROUND
  Studies on endophytes, a relatively under-explored group of microorganisms, are currently popular amongst biologists and natural product researchers. A fungal strain (ME4-2) was isolated from flower samples of mistletoe (Viscum coloratum) during a screening program for endophytes. As limited information on floral endophytes is available, the aim of the present study is to characterise fungal endophytes using their secondary metabolites.
  
  
  RESULTS
  ME4-2 grew well in both natural and basic synthetic media but produced no conidia. Sequence analysis of its internal transcribed spacer rDNA demonstrated that ME4-2 forms a distinct branch within the genus Lasiodiplodia and is closely related to L. pseudotheobromae. This floral endophyte was thus identified as Lasiodiplodia sp. based on its molecular biological characteristics. Five aromatic compounds, including cyclo-(Trp-Ala), indole-3-carboxylic acid (ICA), indole-3-carbaldehyde, mellein and 2-phenylethanol, were found in the culture. The structures of these compounds were determined using spectroscopic methods combined with gas chromatography. To the best of our knowledge, our work is the first to report isolation of these aromatic metabolites from a floral endophyte. Interestingly, ICA, a major secondary metabolite produced by ME4-2, seemed to be biosynthesized via an unusual pathway. Furthermore, our results indicate that the fungus ME4-2 is a potent producer of 2-phenylethanol, which is a common component of floral essential oils.
  
  
  CONCLUSIONS
  This study introduces a fungal strain producing several important aromatic metabolites with pharmaceutical or food applications and suggests that endophytic fungi isolated from plant flowers are promising natural sources of aromatic compounds.
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. qian201@163.com.
authors.forename: Chao-Dong
authors.initials: CD
authors.lastname: Qian
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. fireflyfyh2008@126.com.
authors.forename: Yu-Hang
authors.initials: YH
authors.lastname: Fu
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. jfs1020@163.com.
authors.forename: Fu-Sheng
authors.initials: FS
authors.lastname: Jiang
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. xiaozhutou719@gmail.com.
authors.forename: Zheng-Hong
authors.initials: ZH
authors.lastname: Xu
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. B2006069@163.com.
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Cheng
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. bin.dingcn@yahoo.de.
authors.forename: Bin
authors.initials: B
authors.lastname: Ding
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. zjtcmgcx@126.com.
authors.forename: Cheng-Xian
authors.initials: CX
authors.lastname: Gao
authors.affiliation: Zhejiang Chinese Medical University, Hangzhou, Zhejiang province, China. dzszjtcm@163.com.
authors.forename: Zhi-Shan
authors.initials: ZS
authors.lastname: Ding
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D002849:Chromatography, Gas; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D060026:Endophytes / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D035264:Flowers / Q000382:microbiology; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013057:Spectrum Analysis; D028181:Viscum / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D006841:Hydrocarbons, Aromatic; D007211:Indoles; C012382:indole-3-carboxylic acid