A SmelAAT Acyltransferase Variant Causes a Major Difference in Eggplant (Solanum melongena L.) Peel Anthocyanin Composition

Eggplant berries are rich in anthocyanins like delphinidin-3-rutinoside (D3R) and nasunin (NAS), which are accumulated at high amounts in the peel. NAS is derived by D3R through acylation and glycosylation steps. The presence of D3R or NAS is usually associated with black-purple or lilac fruit coloration of the most cultivated varieties, respectively. Building on QTL mapping position, a candidate gene approach was used to investigate the involvement of a BAHD anthocyanin acyltransferase (SmelAAT) in determining anthocyanin type. The cDNA sequence comparison revealed the presence of a single-base deletion in D3R-type line ‘305E40’ (305E40_aat) with respect to the NAS-type reference line ‘67/3’. This is predicted to cause a frame shift mutation, leading to a loss of SmelAAT function and, thus, D3R retention. RT-qPCR analyses confirmed SmelAAT and 305E40_aat expression during berry maturation. In D3R-type lines, ‘305E40’ and ‘DR2’ overexpressing the functional SmelAAT allele from ‘67/3’, the transcript levels of the transgene, correlated with the accumulation of NAS in fruit peel. Furthermore, it was also found a higher expression of the transcript for glucosyltransferase Smel5GT1, putatively involved with SmelAAT in the last steps of anthocyanin decoration. Finally, an indel marker matching with anthocyanin type in the ‘305E40’ × ’67/3’ segregating population was developed and validated in a wide number of accessions, proving its usefulness for breeding purposes.

Characterization of Anthocyanins From Intraspecific Crosses of Monastrell With Other Premium Varieties

One way in which the wine sector is reacting to the challenge of climate change is to develop plant material that is adapted to the new conditions. Such a strategy will allow the continuation of quality viticulture in traditional winemaking areas that will otherwise be abandoned. The objective of this study was to characterize the anthocyanin composition and content of selected intraspecific hybrids of Monastrell with two other varieties (Syrah and Cabernet Sauvignon). The experiment was carried out over three successive seasons, and the polyphenolic quality of the grapes and wines was assessed along with the adaptation of the hybrids to the high temperatures which will inevitably affect our area (south-eastern Spain). The results showed that, compared with grapes of the Monastrell variety and the wines made from them, most of the hybrids (MS10, MS34, and MC111) had a higher total anthocyanin concentration and overall content of acylated anthocyanins, depending on the year studied.