Solanum melongena, L.

Meyer, Rachel S., Whitaker, Bruce D., Little, Damon P., Wu, Shi-Biao, Kennelly, Edward J., Long, Chun-Lin & Litt, Amy, 2015, Parallel reductions in phenolic constituents resulting from the domestication of eggplant, Phytochemistry 115 (1), pp. 194-206 : 200

2.6. Differences in S. melongena profiles among genetic clusters

To assess whether the eggplants from lineages of mainland origins ( India and China) were chemically distinct from each other or from the lineage largely made up of island (Malesian) landraces, chemical differences, if any, were explored among the clusters in the PCoA remade from the AFLP data ( Meyer et al., 2012b) containing only S. melongena samples used in this study. The PCoA resolved three clusters, in which the Chinese eggplants fell into both of the more populated clusters but were overrepresented in one (R), the Indian eggplants fell into the other of these clusters (L), and the small-fruited S. melongena subsp. ovigerum accessions, from SE Asia and Malesia, fell into the third, smaller, cluster (T) ( Fig. 5 ). ANOVA was used to assess whether there were differences in the abundance of any compounds among the three clusters, which would characterize the clusters for differences attributed to divergent selection on the lineages defined by genetic distance and geographic structure.

ANOVA was performed for each of the 20 compounds that were present in at least one S. melongena accession. Results established six compounds that were significantly different in abundance (p <0.05) among the three clusters ( Table 5 ), but these differences were between S. melongena subsp. ovigerum and the two mainland lineages; the two mainland lineages were not distinct from each other. Four of these compounds were the HCAAs (7, 9, 11, 12) and the remaining two compounds were tryptophan (32) and 5- O -[Z]-CQA (17). Five of these compounds [all but tryptophan (32)] were the most abundant in cluster T, representing S. melongena subsp. ovigerum and the Malesian lineage ( Fig. 5 , Table 5 ). The finding that the island lineage of eggplant was distinguished by relatively high abundance of HCAAs, whereas mainland eggplant lineages were not chemically distinct, suggests this subspecies underwent a strikingly different evolutionary trajectory.

Figures

Fig. 5. AFLP plot of only S. melongena samples. L, R, and T indicate delimitations for left, right, and top clusters that are subsets of the AFLP clusters in Meyer et al. (2012b), which represent hypothesized common lineages of three separate domestication events. Clusters are hypothesized to represent the following lineages: L = Indian background, R = Chinese background, T = Malesian background (S. melongena subsp. ovigerum) .