Genetic mapping, synteny, and physical location of two loci for Fusarium oxysporum f. sp. tracheiphilum race 4 resistance in cowpea [Vignaunguiculata (L.) Walp].

Fusarium wilt is a vascular disease caused by the fungus Fusariumoxysporum f.sp. tracheiphilum (Fot) in cowpea [Vignaunguiculata (L.) Walp]. In this study, we mapped loci conferring resistance to Fot race 4 in three cowpea RIL populations: IT93K-503-1 × CB46, CB27 × 24-125B-1, and CB27 × IT82E-18/Big Buff. Two independent loci which confer resistance to Fot race 4 were identified, Fot4-1 and Fot4-2. Fot4-1 was identified in the IT93K-503-1 (resistant) × CB46 (susceptible) population and was positioned on the cowpea consensus genetic map, spanning 21.57-29.40 cM on linkage group 5. The Fot4-2 locus was validated by identifying it in both the CB27 (resistant) × 24-125B-1 (susceptible) and CB27 (resistant) × IT82E-18/Big Buff (susceptible) populations. Fot4-2 was positioned on the cowpea consensus genetic map on linkage group 3; the minimum distance spanned 71.52-71.75 cM whereas the maximum distance spanned 64.44-80.23 cM. These genomic locations of Fot4-1 and Fot4-2 on the cowpea consensus genetic map, relative to Fot3-1 which was previously identified as the locus conferring resistance to Fot race 3, established that all three loci were independent. The Fot4-1 and Fot4-2 syntenic loci were examined in Glycine max, where several disease-resistance candidate genes were identified for both loci. In addition, Fot4-1 and Fot4-2 were coarsely positioned on the cowpea physical map. Fot4-1 and Fot4-2 will contribute to molecular marker development for future use in marker-assisted selection, thereby expediting introgression of Fot race 4 resistance into future cowpea cultivars

Identification of candidate genes and molecular markers for heat-induced brown discoloration of seed coats in cowpea [Vigna unguiculata (L.) Walp].

BackgroundHeat-induced browning (Hbs) of seed coats is caused by high temperatures which discolors the seed coats of many legumes, affecting the visual appearance and quality of seeds. The genetic determinants underlying Hbs in cowpea are unknown.ResultsWe identified three QTL associated with the heat-induced browning of seed coats trait, Hbs-1, Hbs-2 and Hbs-3, using cowpea RIL populations IT93K-503-1 (Hbs positive) x CB46 (hbs negative) and IT84S-2246 (Hbs positive) x TVu14676 (hbs negative). Hbs-1 was identified in both populations, accounting for 28.3% -77.3% of the phenotypic variation. SNP markers 1_0032 and 1_1128 co-segregated with the trait. Within the syntenic regions of Hbs-1 in soybean, Medicago and common bean, several ethylene forming enzymes, ethylene responsive element binding factors and an ACC oxidase 2 were observed. Hbs-1 was identified in a BAC clone in contig 217 of the cowpea physical map, where ethylene forming enzymes were present. Hbs-2 was identified in the IT93K-503-1 x CB46 population and accounted for of 9.5 to 12.3% of the phenotypic variance. Hbs-3 was identified in the IT84S-2246 x TVu14676 population and accounted for 6.2 to 6.8% of the phenotypic variance. SNP marker 1_0640 co-segregated with the heat-induced browning phenotype. Hbs-3 was positioned on BAC clones in contig512 of the cowpea physical map, where several ACC synthase 1 genes were present.ConclusionThe identification of loci determining heat-induced browning of seed coats and co-segregating molecular markers will enable transfer of hbs alleles into cowpea varieties, contributing to higher quality seeds

Carrot anthocyanins genetics and genomics: Status and perspectives to improve its application for the food colorant industry

Purple or black carrots (Daucus carota ssp. sativus var. atrorubens Alef) are characterized bytheir dark purple- to black-colored roots, owing their appearance to high anthocyanin concentrations. In recent years, there has been increasing interest in the use of black carrot anthocyanins as natural food dyes. Black carrot roots contain large quantities of mono-acylated anthocyanins, which impart a measure of heat-, light- and pH-stability, enhancing the color-stability of food products over their shelf-life. The genetic pathway controlling anthocyanin biosynthesis appears well conserved among land plants; however, different variants of anthocyanin-related genes between cultivars results in tissue-specific accumulations of purple pigments. Thus, broad genetic variations of anthocyanin profile, and tissue-specific distributions in carrot tissues and organs, can be observed, and the ratio of acylated to non-acylated anthocyanins varies significantly in the purple carrot germplasm. Additionally, anthocyanins synthesis can also be influenced by a wide range of external factors, such as abiotic stressors and/or chemical elicitors, directly affecting the anthocyanin yield and stability potential in food and beverage applications. In this study, we critically review and discuss the current knowledge on anthocyanin diversity, genetics and the molecular mechanisms controlling anthocyanin accumulation in carrots. We also provide a view of the current knowledge gaps and advancement needs as regards developing and applying innovative molecular tools to improve the yield, product performance and stability of carrot anthocyanin for use as a natural food colorant.Fil: Iorizzo, Massimo. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Curaba, Julien. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Pottorff, Marti. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Ferruzzi, Mario G.. North Carolina State University. Department Of Food, Bioprocessing And Nutrition Sciences. Plants For Human Health Institute.; Estados UnidosFil: Simon, Pihilipp W.. United States Department of Agriculture. Agricultural Research Service; Argentina. University of Wisconsin; Estados UnidosFil: Cavagnaro, Pablo Federico. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuaria. Cátedra de Horticultura y Floricultura; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

There and back again: historical perspective and future directions for Vaccinium breeding and research studies

The genus Vaccinium L. (Ericaceae) contains a wide diversity of culturally and economically important berry crop species. Consumer demand and scientific research in blueberry (Vaccinium spp.) and cranberry (Vaccinium macrocarpon) have increased worldwide over the crops' relatively short domestication history (~100 years). Other species, including bilberry (Vaccinium myrtillus), lingonberry (Vaccinium vitis-idaea), and ohelo berry (Vaccinium reticulatum) are largely still harvested from the wild but with crop improvement efforts underway. Here, we present a review article on these Vaccinium berry crops on topics that span taxonomy to genetics and genomics to breeding. We highlight the accomplishments made thus far for each of these crops, along their journey from the wild, and propose research areas and questions that will require investments by the community over the coming decades to guide future crop improvement efforts. New tools and resources are needed to underpin the development of superior cultivars that are not only more resilient to various environmental stresses and higher yielding, but also produce fruit that continue to meet a variety of consumer preferences, including fruit quality and health related trait

Genetic Mapping of Fusarium oxysporum f.sp. tracheiphilum Race 3 and Race 4, Macrophomina phaseolina Resistance and Other Traits in Cowpea (Vigna unguiculata [L.] Walp).

Cowpea (Vigna unguiculata) is a legume crop which is grown in many warm regions around the world. Genomic resources have been developed for cowpea which has enabled the identification of QTL and candidate genes which can be utilized in trait improvement.Fungal diseases cause significant constraints to cowpea yield. Fusarium oxysporum f.sp. tracheiphilum (Fot) race 3 and race 4 cause vascular wilt disease and are problematic in California. Genetic mapping identified the Fot3-1 locus which confers resistance to Fot race 3 in the CB27 x 24-125B-1 population. Fot3-1 was identified on BAC clone CH093L18, which carries leucine-rich repeat serine/threonine protein kinases. QTLs were identified which confer resistance against Fot race 4. Fot4-1 was identified in the IT93K-503-1 x CB46 population and Fot4-2 was identified in the CB27 x 24-125B-1 and CB27 x IT82E-18(Big Buff) populations. The syntenic loci for Fot4-1 and Fot4-2 were examined with Glycine max, where several disease resistance candidate genes were identified. Macrophomina phaseolina is a fungal pathogen which causes diseases under high temperatures and drought-stress. QTLs, Mac-10, Mac-11, Mac-12 and Mac-13, were identified in the Sanzi x Vita 7 population. The Mac-11 locus was positioned within BAC clone CH038D17 where an auxin response factor was present. Mac-13 was identified within BAC clones CH062O11 and CH069K06, where an auxin-responsive GH3 family protein was present. Leaf morphology was studied in the cowpea RIL population, Sanzi x Vita 7, in which a QTL was identified for leaf shape, Hls. High co-linearity was observed for the syntenic Hls region in Medicago truncatula and Glycine max where EZA1/SWINGER genes were present. Heat-induced browning of seed coats is caused by high temperatures which discolors the seed coats of cowpea. Three QTL, Hbs-1, Hbs-2, and Hbs-3, were identified using cowpea RIL populations IT93K-503-1 x CB46 and IT84S-2246 x TVu14676. Hbs-1 was identified in BAC clone CM018C23 where ethylene forming enzymes were present. Hbs-3 was identified in BAC clones CH047M01 and CM014K16 where ACC synthase genes were present. Practical outcomes from these studies are the identification of molecular markers which can be used in a Marker Assisted Selection breeding scheme, which should expedite variety development for cowpea

Comparative multi-parameters approach to dissect texture subcomponents of highbush blueberry cultivars at harvest and postharvest

Fruit texture and firmness are important cues of blueberry quality for the fresh market. These attributes contribute to consumer acceptance, resistance to bruising during harvesting and transportation, and shelf-life. Thus, fruit firmness and texture are major priorities for blueberry breeders, producers and distributors. In this study, the discriminative power of texture analysis was examined using penetration tests with different probes and double compression for texture profile analysis (TPA). Mechanical parameters taken from the force deformation curves used to dissect texture subcomponents in blueberries that are associated with specific tissue layers. Principal component analysis (PCA) allows to filter and identify mechanical parameters that significantly discern the most variation amongst 24 blueberry genotypes and showed that texture in this crop is multi-trait and cultivar-dependent. Texture analysis was used also on blueberries stored over six weeks to identify mechanical parameters that could be used as predictors for long shelf life. Additionally, the mechanical parameters were correlated with dynamometer data to determine the utility and accuracy of a simple handheld device to measure fruit firmness in blueberries. This study provides a framework for the identification and characterization of the subcomponents of texture in highbush blueberr

Identification of candidate genes and molecular markers for heat-induced brown discoloration of seed coats in cowpea [Vigna unguiculata (L.) Walp].

BackgroundHeat-induced browning (Hbs) of seed coats is caused by high temperatures which discolors the seed coats of many legumes, affecting the visual appearance and quality of seeds. The genetic determinants underlying Hbs in cowpea are unknown.ResultsWe identified three QTL associated with the heat-induced browning of seed coats trait, Hbs-1, Hbs-2 and Hbs-3, using cowpea RIL populations IT93K-503-1 (Hbs positive) x CB46 (hbs negative) and IT84S-2246 (Hbs positive) x TVu14676 (hbs negative). Hbs-1 was identified in both populations, accounting for 28.3% -77.3% of the phenotypic variation. SNP markers 1_0032 and 1_1128 co-segregated with the trait. Within the syntenic regions of Hbs-1 in soybean, Medicago and common bean, several ethylene forming enzymes, ethylene responsive element binding factors and an ACC oxidase 2 were observed. Hbs-1 was identified in a BAC clone in contig 217 of the cowpea physical map, where ethylene forming enzymes were present. Hbs-2 was identified in the IT93K-503-1 x CB46 population and accounted for of 9.5 to 12.3% of the phenotypic variance. Hbs-3 was identified in the IT84S-2246 x TVu14676 population and accounted for 6.2 to 6.8% of the phenotypic variance. SNP marker 1_0640 co-segregated with the heat-induced browning phenotype. Hbs-3 was positioned on BAC clones in contig512 of the cowpea physical map, where several ACC synthase 1 genes were present.ConclusionThe identification of loci determining heat-induced browning of seed coats and co-segregating molecular markers will enable transfer of hbs alleles into cowpea varieties, contributing to higher quality seeds

Genetic mapping, synteny, and physical location of two loci for Fusarium oxysporum f. sp. tracheiphilum race 4 resistance in cowpea [Vignaunguiculata (L.) Walp].

Fusarium wilt is a vascular disease caused by the fungus Fusariumoxysporum f.sp. tracheiphilum (Fot) in cowpea [Vignaunguiculata (L.) Walp]. In this study, we mapped loci conferring resistance to Fot race 4 in three cowpea RIL populations: IT93K-503-1 × CB46, CB27 × 24-125B-1, and CB27 × IT82E-18/Big Buff. Two independent loci which confer resistance to Fot race 4 were identified, Fot4-1 and Fot4-2. Fot4-1 was identified in the IT93K-503-1 (resistant) × CB46 (susceptible) population and was positioned on the cowpea consensus genetic map, spanning 21.57-29.40 cM on linkage group 5. The Fot4-2 locus was validated by identifying it in both the CB27 (resistant) × 24-125B-1 (susceptible) and CB27 (resistant) × IT82E-18/Big Buff (susceptible) populations. Fot4-2 was positioned on the cowpea consensus genetic map on linkage group 3; the minimum distance spanned 71.52-71.75 cM whereas the maximum distance spanned 64.44-80.23 cM. These genomic locations of Fot4-1 and Fot4-2 on the cowpea consensus genetic map, relative to Fot3-1 which was previously identified as the locus conferring resistance to Fot race 3, established that all three loci were independent. The Fot4-1 and Fot4-2 syntenic loci were examined in Glycine max, where several disease-resistance candidate genes were identified for both loci. In addition, Fot4-1 and Fot4-2 were coarsely positioned on the cowpea physical map. Fot4-1 and Fot4-2 will contribute to molecular marker development for future use in marker-assisted selection, thereby expediting introgression of Fot race 4 resistance into future cowpea cultivars