Genome Size, Base Composition, and Ploidy Analysis in Scarlet Eggplant (Solanum aethiopicum L.), Poster Board #405

Solanum aethiopicum L. (scarlet eggplant), native to sub-Saharan Africa, is found throughout tropical Africa, South and North America, Asia, as well as southern Europe.  Its fruit, leaves, shoots, and roots are used for both food and medicinal purposes; the specific use depends on the geographic area and/or plant type.  S. aethiopicum is sometimes used as an ornamental and also as a rootstock for tomato and common eggplant because of its resistance to certain fungal pathogens. Despite its potential as a food, medicinal, and ornamental crop, very little is known about S. aethiopicum genome that will be useful in crop improvement. Therefore, flow cytometry was used to assess the ploidy, genome size, and base composition of 12 morphologically different S. aethiopicum accessions from different geographic regions (Africa, South America, and Europe). Nuclei were extracted from young leaves and stained with fluorochromes  - 4′, 6-diamidino-2-phenylindole (DAPI) or propidium iodide (PI). Fluorescence ratios, calculated relative to the internal reference Pisum sativum (cv. ‘Ctirad’, 2c = 9.09 pg), were converted to DNA content values and expressed in picograms (pg) and megabase pairs (Mbp). Base pair composition (%AT) was determined using DAPI and PI. The diploid nature (2n = 2x = 24) of S. aethiopicum was confirmed. The 2C nuclear DNA content of the accessions ranged from 2.62 pg (2565.48 Mbp) for PI 420230 to 3.08 pg (3008.40 Mbp) for PI 420226. Only the accession PI420226 was significantly different from the other genotypes, suggesting the stability of S. aethiopicum genome size. Similarly, very little variation was found among the accessions for base pair composition, which varied from 56.73 to 57.84% AT. The results obtained can be useful for future sequencing, cytogenetic, taxonomic, and breeding endeavors in S. aethiopicum.