Genetic fingerprinting of germplasm accessions as an aid for species conservation: a case study with Borderea chouardii (Dioscoreaceae), one of the most critically endangered Iberian plants.
OBJECTIVE
Molecular markers have changed previous expectations about germplasm collections of endangered plants, as new perspectives aim at holding a significant representation of all the genetic diversity in the studied species to accomplish further conservation initiatives successfully. Borderea chouardii is a critically endangered allotetraploid dioecious member of Dioscoreaceae, known from a single population in the Iberian pre-Pyrenees. This population was reported to be highly structured into two genetically distinct groups of individuals corresponding to their spatial separation along the vertical cliff where it grows. In 1999, the Spanish Government of Aragón launched the first conservation programme for the ex situ preservation of this species, and since then a seed collection has been conserved at the Germplasm Bank of the Universidad Politécnica de Madrid. However, as some seed samples had not been labelled clearly at the time of collection, their origin was uncertain.


METHODS
Genetic variation in germplasm accessions of B. chouardii was investigated using microsatellite (simple sequence repeat; SSR) markers.


RESULTS
The 17 primer pairs used detected 62 SSR alleles in the 46 samples analysed from five different germplasm stocks. Eight alleles scored from the wild population were not detected in the germplasm samples analysed. The relatedness of the germplasm samples to the wild subpopulations through neighbour-joining clustering, principal coordinates analysis (PCO) and assignment tests revealed a biased higher representation of the genetic diversity of the lower cliff (43 samples) subpopulation than that of the upper cliff (three samples).


CONCLUSIONS
The collection of additional samples from the upper cliff is recommended to achieve a better representation of the genetic diversity of this subpopulation. It is also recommended that these stocks should be managed separately according to their distinct microspatial origin in order to preserve the genetic substructuring of the wild population.
Segarra-Moragues
José Gabriel
JG
Departamento de Agricultura y Economía Agraria, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, C/Carretera de Cuarte s/n, E-22071 Huesca, Spain. jogasemo@unizar.es
Iriondo
José María
JM
Catalán
Pilar
P
D000483:Alleles; D003247:Conservation of Natural Resources / Q000379:methods*; D016172:DNA Fingerprinting; D027743:Dioscoreaceae / Q000235:genetics*; D014644:Genetic Variation; D010802:Phylogeny; D013030:Spain; D018911:Trinucleotide Repeats