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Abstract Plants regenerated from seedling explants (hypocotyls and cotyledons) of the Solanaceae family membersPhysalis grisea(groundcherry),Solanum lycopersicum(tomato), andSolanum prinophyllum(forest nightshade) were used to determine the in vitro culture parameters that contribute to the incidence in polyploidization of tissue culture-derived plants (regenerants) from these species. We examined the possible effects of zeatin concentration in the plant regeneration medium, explant source, and species. Plants were grown to maturity under greenhouse conditions, pollen was collected and germinated. Flow cytometry analysis verified the utility of the pollen germination method for determining differences in ploidy, which was based on the number of pollen tubes produced with one tube representing diploid and two indicating polyploid. As for zeatin concentration, we assessed the effect of our standard method of initiation on medium containing 2 mg/l followed by 1 mg/l 2 weeks after culture initiation in comparison with 0.25, 0.5, and 1 mg/l throughout the culture lifetime. There were no major correlations for zeatin concentration on ploidy status across the species except for plants regenerated fromS. lycopersicumhypocotyl explants where the percentage of polyploid regenerants increased with increasing concentrations. As for species and explant effects,P. griseaplants regenerated from hypocotyl explants had the highest percentage of polyploid plants at 81% compared to 43% and 35% forS. lycopersicumandS. prinophyllum, respectively. From cotyledons, 8% ofS. lycopersicumand 20% ofS. prinophyllumwere polyploid. A comparison withP. griseacould not be made because cotyledon explants do not regenerate on zeatin-containing medium. The results indicated the incidence of polyploidization cannot be generalized for zeatin concentration, however, an influence of explant type and species was observed. Effects of increased ploidy on plant morphology were primarily larger flower and seed size; however, no significant differences were observed in plant or fruit size.
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Chromosome-scale genome assemblies of wild tomato relatives Solanum habrochaites and Solanum galapagense reveal structural variants associated with stress tolerance and terpene biosynthesis
- Award ID(s):
- 1855585
- PAR ID:
- 10410293
- Date Published:
- Journal Name:
- Horticulture Research
- Volume:
- 9
- ISSN:
- 2052-7276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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SUMMARY Wild relatives of tomato are a valuable source of natural variation in tomato breeding, as many can be hybridized to the cultivated species (Solanum lycopersicum). Several, includingSolanum lycopersicoides, have been crossed toS. lycopersicumfor the development of ordered introgression lines (ILs), facilitating breeding for desirable traits. Despite the utility of these wild relatives and their associated ILs, few finished genome sequences have been produced to aid genetic and genomic studies. Here we report a chromosome‐scale genome assembly forS. lycopersicoidesLA2951, which contains 37 938 predicted protein‐coding genes. With the aid of this genome assembly, we have precisely delimited the boundaries of theS. lycopersicoidesintrogressions in a set ofS. lycopersicumcv. VF36 × LA2951 ILs. We demonstrate the usefulness of the LA2951 genome by identifying several quantitative trait loci for phenolics and carotenoids, including underlying candidate genes, and by investigating the genome organization and immunity‐associated function of the clusteredPtogene family. In addition, syntenic analysis of R2R3MYB genes sheds light on the identity of theAuberginelocus underlying anthocyanin production. The genome sequence and IL map provide valuable resources for studying fruit nutrient/quality traits, pathogen resistance, and environmental stress tolerance. We present a new genome resource for the wild speciesS. lycopersicoides, which we use to shed light on theAuberginelocus responsible for anthocyanin production. We also provide IL boundary mappings, which facilitated identifying novel carotenoid quantitative trait loci of which one was likely driven by an uncharacterized lycopene β‐cyclase whose function we demonstrate.more » « less
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/hr/uhac139
