Examinando por Materia "Carrot"

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Extended studies of interspecific relationships in Daucus (Apiaceae) using DNA sequences from ten nuclear orthologues
(Oxford University, 2019-09-24) Martínez Flores, Fernando; Crespo, Manuel B.; Geoffriau, Emmanuel; Allender, Charlotte; Ruess, Holly; Arbizu Berrocal, Carlos Irvin; Simon, Philipp W.; Spooner, David M.
Daucus has traditionally been estimated to comprise 21–25 species, but a recent study expanded the genus to c. 40 species. The present study uses ten nuclear orthologues to examine 125 accessions, including 40 collections of 11 species (D. annuus, D. arcanus, D. decipiens, D. durieua, D. edulis, D. gracilis, D. minusculus, D. montanus, D. pumilus, D. setifolius and D. tenuissimus) newly examined with nuclear orthologues. As in previous nuclear orthologue studies, Daucus resolves into two well-defined clades, and groups different accessions of species together. Maximum likelihood and maximum parsimony analyses provide concordant results, but SVD quartets reveals many areas of disagreement of species within these two major clades. With maximum likelihood and maximum parsimony analyses Daucus montanus (hexaploid) is resolved as an allopolyploid between D. pusillus (diploid) and D. glochidiatus (tetraploid), whereas with SVD quartets it is resolved as an allopolyploid between D. glochidiatus and an unknown Daucus sp. We propose the new combination Daucus junceus (Durieua juncea) for a neglected species endemic to the south-western Iberian Peninsula often referred to as D. setifolius, and we place D. arcanus in synonymy with D. pusillus. Three lectotypes are also designated.
Genotyping-by-sequencing provides the discriminating power to investigate the subspecies of Daucus carota (Apiaceae)
(Springer Nature, 2016-10-28) Arbizu Berrocal, Carlos Irvin; Ellison, Shelby L.; Senalik, Douglas; Simon, Philipp W.; Spooner, David M.
Results: We used GBS to obtain SNPs covering all nine Daucus carota chromosomes from 162 accessions of Daucus and two related genera. To study Daucus phylogeny, we scored a total of 10,814 or 38,920 SNPs with a maximum of 10 or 30% missing data, respectively. To investigate the subspecies of D. carota, we employed two data sets including 150 accessions: (i) rate of missing data 10% with a total of 18,565 SNPs, and (ii) rate of missing data 30%, totaling 43,713 SNPs. Consistent with prior results, the topology of both data sets separated species with 2n = 18 chromosome from all other species. Our results place all cultivated carrots (D. carota subsp. sativus) in a single clade. The wild members of D. carota from central Asia were on a clade with eastern members of subsp. sativus. The other subspecies of D. carota were in four clades associated with geographic groups: (1) the Balkan Peninsula and the Middle East, (2) North America and Europe, (3) North Africa exclusive of Morocco, and (4) the Iberian Peninsula and Morocco. Daucus carota subsp. maximus was discriminated, but neither it, nor subsp. gummifer (defined in a broad sense) are monophyletic. Conclusions: Our study suggests that (1) the morphotypes identified as D. carota subspecies gummifer (as currently broadly circumscribed), all confined to areas near the Atlantic Ocean and the western Mediterranean Sea, have separate origins from sympatric members of other subspecies of D. carota, (2) D. carota subsp. maximus, on two clades with some accessions of subsp. carota, can be distinguished from each other but only with poor morphological support, (3) D. carota subsp. capillifolius, well distinguished morphologically, is an apospecies relative to North African populations of D. carota subsp. carota, (4) the eastern cultivated carrots have origins closer to wild carrots from central Asia than to western cultivated carrots, and (5) large SNP data sets are suitable for species-level phylogenetic studies in Daucus
Inter-primer binding site (iPBS) retrotransposon markers provide insights into the genetic diversity and population structure of carrots (Daucus, Apiaceae)
(TUBITAK, 2022-04-25) Yildiz, Mehtap; Arbizu Berrocal, Carlos Irvin
Studies of genetic diversity and population structure are essential as an initial step in conservation and breeding programs for modern crops. Carrot (Daucus spp.) is among the ten most important vegetables worldwide, however, its genetic structure and phylogenetic relationships are not totally deciphered. Here, we explored the utility of 21 inter-primer binding site (iPBS) retrotransposon markers to determine the genetic diversity and population structure of 38 accessions of Daucus and one accession of a related genus. The manual scoring revealed 309 bands based on their presence/absence. The dendrogram based on the UPGMA clustering algorithm and a principal coordinate analysis (PCoA) indicated the presence of four clusters. The Daucus species with 2n = 18 chromosome (subclade A´) separated from the other two species D. pusillus and D. muricatus, which were positioned into two individual clusters. The other clade includes the Daucus from the B group. It was also noticed that few accessions were intermixed amongst clusters. Different genetic diversity parameters were estimated based on the four clusters (populations) defined by STRUCTURE software, demonstrating that clusters 3 and 4 possessed the lowest and highest diversity values, respectively. AMOVA showed variation between and within clusters of 41.85% and 58.15%, respectively. The highest population divergence (Fst) was observed between clusters 2 and 3 (0.579), on the other hand, clusters 1 and 4 depicted the lowest Fst with 0.160. Our research highlighted that iPBS markers were successful and effective to study Daucus genetic diversity. These results will contribute to the genetic improvement of carrots and sustainable management of its diversity.
Phylogenomics of the Carrot Genus (Daucus, Apiaceae)
(John Wiley & Sons, 2014-10-01) Arbizu Berrocal, Carlos Irvin; Ruess, Holly; Senalik, Douglas; Simon, Philipp W.; Spooner, David M.
•Premise of the study: We explored the utility of multiple nuclear orthologs for the taxonomic resolution of wild and cultivated carrot, Daucus species. •Methods: We studied the phylogeny of 92 accessions of 13 species and two subspecies of Daucus and 15 accessions of related genera (107 accessions total) with DNA sequences of 94 nuclear orthologs. Reiterative analyses examined data of both alleles using ambiguity codes or a single allele with the highest coverage, trimmed vs. untrimmed homopolymers; pure exonic vs. pure intronic data; the use of all 94 markers vs. a reduced subset of markers; and analysis of a concatenated data set vs. a coalescent (species tree) approach. •Key results: Our maximum parsimony and maximum likelihood trees were highly resolved, with 100% bootstrap support for most of the external and many of the internal clades. They resolved multiple accessions of many different species as monophyletic with strong support, but failed to support other species. The single allele analysis gave slightly better topological resolution; trimming homopolymers failed to increase taxonomic resolution; the exonic data had a smaller proportion of parsimony‐informative characters. Similar results demonstrating the same dominant topology can be obtained with many fewer markers. A Bayesian concordance analysis provided an overall similar phylogeny, but the coalescent analysis provided drastic changes in topology to all the above. •Conclusions: Our research highlights some difficult species groups in Daucus and misidentifications in germplasm collections. It highlights a useful subset of markers and approaches for future studies of dominant topologies in Daucus.