Identification of Amazonian trees with DNA barcodes.
BACKGROUND
Large-scale plant diversity inventories are critical to develop informed conservation strategies. However, the workload required for classic taxonomic surveys remains high and is particularly problematic for megadiverse tropical forests.


RESULTS
Based on a comprehensive census of all trees in two hectares of a tropical forest in French Guiana, we examined whether plant DNA barcoding could contribute to increasing the quality and the pace of tropical plant biodiversity surveys. Of the eight plant DNA markers we tested (rbcLa, rpoC1, rpoB, matK, ycf5, trnL, psbA-trnH, ITS), matK and ITS had a low rate of sequencing success. More critically, none of the plastid markers achieved a rate of correct plant identification greater than 70%, either alone or combined. The performance of all barcoding markers was noticeably low in few species-rich clades, such as the Laureae, and the Sapotaceae. A field test of the approach enabled us to detect 130 molecular operational taxonomic units in a sample of 252 juvenile trees. Including molecular markers increased the identification rate of juveniles from 72% (morphology alone) to 96% (morphology and molecular) of the individuals assigned to a known tree taxon.


CONCLUSIONS
We conclude that while DNA barcoding is an invaluable tool for detecting errors in identifications and for identifying plants at juvenile stages, its limited ability to identify collections will constrain the practical implementation of DNA-based tropical plant biodiversity programs.
Gonzalez
Mailyn Adriana
MA
Laboratoire Evolution et Diversité Biologique, Université Paul Sabatier and CNRS, UMR 5174, Toulouse, France.
Baraloto
Christopher
C
Engel
Julien
J
Mori
Scott A
SA
Pétronelli
Pascal
P
Riéra
Bernard
B
Roger
Aurélien
A
Thébaud
Christophe
C
Chave
Jérôme
J
D044822:Biodiversity; D016000:Cluster Analysis; D018744:DNA, Plant / Q000235:genetics*; D001330:Electronic Data Processing; D005616:French Guiana; D005819:Genetic Markers; D015233:Models, Statistical; D010802:Phylogeny; D012621:Seasons; D017422:Sequence Analysis, DNA; D014197:Trees / Q000145:classification* / Q000235:genetics*
D018744:DNA, Plant; D005819:Genetic Markers