Who orchestrates phenylpropanoids biosynthesis in eggplant? A search for candidate TF regulators

S. melongena (eggplant) is a food plant, whose fruits are widely consumed worldwide. Fruits have a high content in polyphenols, among which chlorogenic acid (CGA) represents the 80-90% of the total phenols molecules. Due to the wide range of health promoting effects of polyphenols, a considerable scientific interest has been addressed towards the production of high quality S. melongena varieties improved for their CGA and polyphenol composition. However, opposite to tomato and potato, genomic information on the regulation of phenylpropanoid and CGA biosynthesis in this Solanaceous specie is still lacking. In search for a MYB TF regulator of phenylpropanoid pathway in eggplant, we used a S. tuberosum MYB TF regulator of CGA and flavonols biosynthesis (EU310399.1) as query for mining the available S. melongena EST's database (Fukuoka et al, 2011). S. melongena EST SmFL27I13 was used to design 5' and 3' end RACE primers for the isolation of an homologous MYB transcription factor. From S. melongena leaves, an ORF (open reading frame) of 741 bp encoding for a 247 aa protein was identified. tBlast analysis indicates S. lycopersicum Ant1 (NM_001247488.1), S. tuberosum Myb113 (XM_006366078.1) and Cai (EU310399.1) as having the highest similarity (76%, 72% and 67%, respectively) to our putative TF from eggplant. Developmental and temporal expression of this TF and of relevant key phenylpropanoid genes (PAL, HQT, DFR, ANS) has been investigated in several eggplant tissues, such as young and mature leaves, stems, roots and flowers and variable transcript levels were detected among these tissues. In the attempt of understand the function of this novel S. melongena TF in relation with phenylpropanoid pathway, here we report our molecular genetic approach and our findings. This work was supported by the Project GenHORT PON02_00395_3215002 funded by the Italian Ministry of Education, University and Research (MIUR), PON R&C 2007-2013.