title: trnL-F is a powerful marker for DNA identification of field vittarioid gametophytes (Pteridaceae).
abstract: OBJECTIVE
  The gametophyte phase of ferns plays an important role in habitat selection, dispersal, adaptation and evolution. However, ecological studies on fern gametophytes have been impeded due to the difficulty of species identification of free-living gametophytes. DNA barcoding provides an alternative approach to identifying fern gametophytes but is rarely applied to field studies. In this study, an example of field vittarioid gametophyte identification using DNA barcoding, which has not been done before, is given.
  
  
  METHODS
  A combination of distance-based and tree-based approaches was performed to evaluate the discriminating power of three candidate barcodes (matK, rbcL and trnL-F) on 16 vittarioid sporophytes. Sequences of the trnL-F region were generated from 15 fern gametophyte populations by tissue-direct PCR and were compared against the sporophyte dataset, using BLAST.
  
  
  RESULTS
  trnL-F earns highest primer universality and discriminatory ability scores, whereas PCR success rates were very low for matK and rbcL regions (10·8 % and 41·3 %, respectively). BLAST analyses showed that all the sampled field gametophytes could be successfully identified to species level. Three gametophyte populations were also discovered to be living beyond the known occurrence of their sporophyte counterparts.
  
  
  CONCLUSIONS
  This study demonstrates that DNA barcoding (i.e. reference databasing, tissue-direct PCR and molecular analysis), especially the trnL-F region, is an efficient tool to identify field gametophytes, and has considerable potential in exploring the ecology of fern gametophytes.
authors: Division of Silviculture, Taiwan Forestry Research Institute, Taipei, Taiwan.
authors: Cheng Wei
authors: CW
authors: Chen
authors: Yao Moan
authors: YM
authors: Huang
authors: Li Yaung
authors: LY
authors: Kuo
authors: Quoc Dat
authors: QD
authors: Nguyen
authors: Hong Truong
authors: HT
authors: Luu
authors: John Rey
authors: JR
authors: Callado
authors: Donald R
authors: DR
authors: Farrar
authors: Wen Liang
authors: WL
authors: Chiou
mesh_terms: D000595:Amino Acid Sequence; D058893:DNA Barcoding, Taxonomic / Q000379:methods*; D017753:Ecosystem; D005819:Genetic Markers; D055993:Germ Cells, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D029625:Pteridaceae / Q000235:genetics*; D013624:Taiwan
chemical_list: D005819:Genetic Markers
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