Genomic Fingerprinting of <i>Camelina</i> Species Using cTBP as Molecular Marker

Abstract

Interest on the genus Camelina has recently increased due to the biofuel, or jet fuel, potential of the oil extracted from seeds of the cultivated species Camelina sativa (L.) Crantz. While our knowledge on C. sativa is constantly augmenting, only few studies have been performed on the other species of the genus, which could be a potentially useful material for the genetic improvement of C. sativa. The genus Camelina consists of 11 species, but only six (C. sativa, C. microcarpa, C. alyssum, C. rumelica, C. hispida and C. laxa) could be retrieved from germplasm banks to carry out genomic fingerprinting studies based on the use of the cTBP molecular marker. Each species, with the exception of C. alyssum that is proposed to be a subspecies of C. sativa, shows a distinct cTBP profile resulting from multiple DNA length polymorphisms present in the second intron of the members of the β-tubulin gene family. In contrast to the high level of genetic diversity detected among the six Camelina species, low variability is observed among and within the accessions of the same species, except for C. hispida that is characterized by an intra-accession high number of cTBP polymorphic bands. In addition, cTBP is also able to identify incorrectly classified accessions and provide information on the ploidy level of each species.

Natural trait variation for taxonomic classification and breeding potential assessment in the genus Camelina

“…For instance, no significant difference was observed for oil content between the HG-240 C. hispida accession and C. sativa accessions (Appendix 7.5). Galasso et al (2015) also observed high genetic variability within C. hispida accessions relative to the other Camelina species perhaps indicating that this species may be a predecessor for subsequent polyploid species within the genus. In this case, we hypothesize that the parental ancestors of C. sativa may be the result of a hybridization event between C. hispida (n = 7) and the diploid C. microcarpa (n = 6) or C. laxa (n = 6) due to its basal chromosome numbers of 7+7+6 (Kagale et al, 2014).…”

“…microcarpa and Camelina species in general. A chromosome count of 2n = 26 has been reported for C. rumelica indicating a tetraploid status for this species (Galasso et al, 2015;Martin et al, 2016). Diploid counts of 2n = 14 were reported for C. hispida which has been consistent across several studies (Al-Shehbaz, 1987;Hutcheon et al, 2010;Galasso et al, 2015;Martin et al, 2016) whereas diploid counts of 2n = 12 were reported for C. laxa (Galasso et al, 2015;Martin et al, 2016).…”

“…Camelina species using introns of a family of β-tubulin genes to determine the level of genetic diversity among the genus precisely for the aforementioned purpose. Galasso et al (2015) identified a high level of genetic diversity among six Camelina species, however, low variability was observed among and within accessions of the same species except for Camelina hispida…”

“…Polyploidy poses challenges to traditional breeding and gene manipulation approaches but knowledge of the genome organization of camelina combined with the characterization of its germplasm diversity within and across the genus will accelerate future breeding objectives (Kagale et al, 2014). In fact, Galasso et al (2015) undertook a genomic fingerprinting study for…”

“…The Chromosome counts have varied considerably between the species but 2n = 40 has been most commonly reported among C. alyssum, C. microcarpa, and C. sativa (Séguin-Swartz et al, 2013;Galasso et al, 2015). Various chromosome counts have been documented for C. microcarpa ranging from 2n = 12, 16, 18-20, 26, 32, 38, and 40 and it has recently been suggested that this species comprises three cytotypes (Warwick et al, 2009;Martin et al, 2016).…”