Browsing by Author "Cavagnaro, Pablo F."

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Characterization of Purple Carrot Germplasm for Antioxidant Capacity and Root Concentration of Anthocyanins, Phenolics, and Carotenoids
(Mdpi, 2023) Perez, Maria Belen; Carvajal, Sofia; Beretta, Vanesa; Bannoud, Florencia; Fangio, Maria Florencia; Berli, Federico; Cavagnaro, Pablo F.
The present study characterized a genetically and phenotypically diverse collection of 27 purple and two non-purple (one orange and one yellow) carrot accessions for concentration of root anthocyanins, phenolics, and carotenoids, and antioxidant capacity estimated by four different methods (ORAC, DPPH, ABTS, FRAP), in a partially replicated experimental design comprising data from two growing seasons (2018 and 2019). Broad and significant (p < 0.0001) variation was found among the accessions for all the traits. Acylated anthocyanins (AA) predominated over non-acylated anthocyanins (NAA) in all the accessions and years analyzed, with AA accounting for 55.5-100% of the total anthocyanin content (TAC). Anthocyanins acylated with ferulic acid and coumaric acid were the most abundant carrot anthocyanins. In general, black or solid purple carrots had the greatest TAC and total phenolic content (TPC), and the strongest antioxidant capacities, measured by all methods. Antioxidant capacity, estimated by all methods, was significantly, positively, and moderately-to-strongly correlated with the content of all individual anthocyanins pigments, TAC, and TPC, in both years (r = 0.59-0.90, p < 0.0001), but not with the carotenoid pigments lutein and beta-carotene; suggesting that anthocyanins and other phenolics, but not carotenoids, are major contributors of the antioxidant capacity in purple carrots. We identified accessions with high concentration of chemically stable AA, with potential value for the production of food dyes, and accessions with relatively high content of bioavailable NAA that can be selected for increased nutraceutical value (e.g., for fresh consumption).
Determination of the Effective Radiation Dose for Mutation Breeding in Purple Carrot (Daucus Carota L.) and Possible Variations Formed
(Springer, 2022) Yarar, Gulistan; Kocak, Metin; Denli, Nihal; Cavagnaro, Pablo F.; Yildiz, Mehtap
Background Plant breeding allows altering the genetic structure of plants to meet human needs. The use of radiation technology for inducing mutations and -thereby- new phenotypic variants has become increasingly common as a tool for developing new crops. The aim of this study was to determine the effective gamma irradiation dose for inducing mutations in purple carrot. Methods and results Increasing gamma radiation doses [0, 50, 100, 200, 300, 400, 500, and 600 Gy] were applied to purple carrot seeds. The irradiated seeds were sown in pots and the emergence and survival rates of the seedlings were analyzed. Considering plant emergence (%) as a response variable, the LD50 dose was 387.5 Gy. Analysis of root length, root width (shoulder diameter) and plant height in control (0 Gy) and irradiated plants (50-600 Gy) revealed an inverse association between these morphological traits and radiation dose. SRAP and ISSR markers were used to identify DNA polymorphisms in irradiated and control plants. The range of amplicons per primer set revealed by ISSR and SRAP markers was 4-10 and 2-13, respectively. In the ISSR analysis of the irradiated carrots (for the 8 doses used), we obtained range values for the average Nei's gene diversity, Shannon's information index, and polymorphism information content (PIC) of 0.13-0.25, 0.20-0.35, and 1.39-1.67, respectively, whereas in the SRAP analysis, the range values for these parameters were 0.15-0.25, 0.23-0.37, and 0.43-0.58, respectively. Cluster analysis revealed three main groups; (a) non-irradiated (control) plants, (b) plants from the 600 Gy dose, and (c) a third group with two subgroups: one with individuals from the lowest irradiation doses (50-200 Gy) and a second group with individuals from the highest irradiation doses (300-500 Gy). Conclusions This is the first report on determining effective mutagen doses and genetic characterization of induced mutagenesis via gamma irradiation in purple carrot. ISSR and SRAP markers were successful in detecting variations among different levels of mutagen doses.
Expression and Mapping of Anthocyanin Biosynthesis Genes in Carrot
(Springer, 2013) Yildiz, Mehtap; Willis, David K.; Cavagnaro, Pablo F.; Iorizzo, Massimo; Abak, Kazim; Simon, Philipp W.
Anthocyanin gene expression has been extensively studied in leaves, fruits and flowers of numerous plants. Little, however, is known about anthocyanin accumulation in roots of carrots or other species. We quantified expression of six anthocyanin biosynthetic genes [phenylalanine ammonia-lyase (PAL3), chalcone synthase (CHS1), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR1), leucoanthocyanidin dioxygenase (LDOX2), and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGT)] in three carrot inbreds with contrasting root color: solid purple (phloem and xylem); purple outer phloem/orange xylem; and orange phloem and xylem. Transcripts for five of these genes (CHS1, DFR1, F3H, LDOX2, PAL3) accumulated at high levels in solid purple carrots, less in purple-orange carrot, and low or no transcript in orange carrots. Gene expression coincided with anthocyanin accumulation. In contrast, UFGT expression was comparable in purple and orange carrots and relatively unchanged during root development. In addition, five anthocyanin biosynthesis genes [FLS1 (flavonol synthase), F3H, LDOX2, PAL3, and UFGT] and three anthocyanin transcription factors (DcEFR1, DcMYB3 and DcMYB5) were mapped in a population segregating for the P (1) locus that conditions purple root color. P (1) mapped to chromosome 3 and of the eight anthocyanin biosynthesis genes, only F3H and FLS1 were linked to P (1). The gene expression and mapping data suggest a coordinated regulatory control of anthocyanin expression in carrot root and establish a framework for studying the anthocyanin pathway in carrots, and they also suggest that none of the genes evaluated is a candidate for P (1).
A Gene-Derived Snp-Based High Resolution Linkage Map of Carrot Including the Location of Qtl Conditioning Root and Leaf Anthocyanin Pigmentation
(Bmc, 2014) Cavagnaro, Pablo F.; Iorizzo, Massimo; Yildiz, Mehtap; Senalik, Douglas; Parsons, Joshua; Ellison, Shelby; Simon, Philipp W.
Background: Purple carrots accumulate large quantities of anthocyanins in their roots and leaves. These flavonoid pigments possess antioxidant activity and are implicated in providing health benefits. Informative, saturated linkage maps associated with well characterized populations segregating for anthocyanin pigmentation have not been developed. To investigate the genetic architecture conditioning anthocyanin pigmentation we scored root color visually, quantified root anthocyanin pigments by high performance liquid chromatography in segregating F-2, F-3 and F-4 generations of a mapping population, mapped quantitative trait loci (QTL) onto a dense gene-derived single nucleotide polymorphism (SNP)-based linkage map, and performed comparative trait mapping with two unrelated populations. Results: Root pigmentation, scored visually as presence or absence of purple coloration, segregated in a pattern consistent with a two gene model in an F2, and progeny testing of F-3-F-4 families confirmed the proposed genetic model. Purple petiole pigmentation was conditioned by a single dominant gene that co-segregates with one of the genes conditioning root pigmentation. Root total pigment estimate (RTPE) was scored as the percentage of the root with purple color. All five anthocyanin glycosides previously reported in carrot, as well as RTPE, varied quantitatively in the F2 population. For the purpose of QTL analysis, a high resolution gene-derived SNP-based linkage map of carrot was constructed with 894 markers covering 635.1 cM with a 1.3 cM map resolution. A total of 15 significant QTL for all anthocyanin pigments and for RTPE mapped to six chromosomes. Eight QTL with the largest phenotypic effects mapped to two regions of chromosome 3 with co-localized QTL for several anthocyanin glycosides and for RTPE. A single dominant gene conditioning anthocyanin acylation was identified and mapped. Comparative mapping with two other carrot populations segregating for purple color indicated that carrot anthocyanin pigmentation is controlled by at least three genes, in contrast to monogenic control reported previously. Conclusions: This study generated the first high resolution gene-derived SNP-based linkage map in the Apiaceae. Two regions of chromosome 3 with co-localized QTL for all anthocyanin pigments and for RTPE, largely condition anthocyanin accumulation in carrot roots and leaves. Loci controlling root and petiole anthocyanin pigmentation differ across diverse carrot genetic backgrounds.
Microsatellite Isolation and Marker Development in Carrot - Genomic Distribution, Linkage Mapping, Genetic Diversity Analysis and Marker Transferability Across Apiaceae
(Bmc, 2011) Cavagnaro, Pablo F.; Chung, Sang-Min; Manin, Sylvie; Yildiz, Mehtap; Ali, Aamir; Alessandro, Maria S.; Simon, Philipp W.
Background: The Apiaceae family includes several vegetable and spice crop species among which carrot is the most economically important member, with similar to 21 million tons produced yearly worldwide. Despite its importance, molecular resources in this species are relatively underdeveloped. The availability of informative, polymorphic, and robust PCR-based markers, such as microsatellites (or SSRs), will facilitate genetics and breeding of carrot and other Apiaceae, including integration of linkage maps, tagging of phenotypic traits and assisting positional gene cloning. Thus, with the purpose of isolating carrot microsatellites, two different strategies were used; a hybridization-based library enrichment for SSRs, and bioinformatic mining of SSRs in BAC-end sequence and EST sequence databases. This work reports on the development of 300 carrot SSR markers and their characterization at various levels. Results: Evaluation of microsatellites isolated from both DNA sources in subsets of 7 carrot F-2 mapping populations revealed that SSRs from the hybridization-based method were longer, had more repeat units and were more polymorphic than SSRs isolated by sequence search. Overall, 196 SSRs (65.1%) were polymorphic in at least one mapping population, and the percentage of polymophic SSRs across F-2 populations ranged from 17.8 to 24.7. Polymorphic markers in one family were evaluated in the entire F-2, allowing the genetic mapping of 55 SSRs (38 codominant) onto the carrot reference map. The SSR loci were distributed throughout all 9 carrot linkage groups (LGs), with 2 to 9 SSRs/LG. In addition, SSR evaluations in carrot-related taxa indicated that a significant fraction of the carrot SSRs transfer successfully across Apiaceae, with heterologous amplification success rate decreasing with the target-species evolutionary distance from carrot. SSR diversity evaluated in a collection of 65 D. carota accessions revealed a high level of polymorphism for these selected loci, with an average of 19 alleles/locus and 0.84 expected heterozygosity. Conclusions: The addition of 55 SSRs to the carrot map, together with marker characterizations in six other mapping populations, will facilitate future comparative mapping studies and integration of carrot maps. The markers developed herein will be a valuable resource for assisting breeding, genetic, diversity, and genomic studies of carrot and other Apiaceae.