Intronless tandem duplicated class I sHSP genes involved in Solanum lycopersicum (cv Heinz 1706) fruit ripening

KRSTICEVIC, F.J.; ARCE, D.P.; PRATTA, G.; TAPIA, E.

Bordeaux

Conferencia; 12th Solanaceae Conference (SOL 2015); 2015

SOL (Salanaceae Internacional Conference)

The tomato S. lycopersicum (cv Heinz 1706) is a centerpiece of the Solanaceae family and its genome constitutes a reference in the fleshy fruit development study. Therefore, comparing Solanaceae genomic data is possible to detect gene duplication events and hypothesized their mechanisms of origin. In S. lycopersicum (cv Heinz 1706) duplication events are the principal source of small heat shock proteins (sHsps) gene family expansion. Goyal (2012) identified an intronless subfamily ofcytosolic class I sHsps in the chromosome 6 of in S. lycopersicum cv. Ohio 8245. The subfamily it is conformed by three members genes (Solyc06g076540, Solyc06g076560 and Solyc06g076570) alias Sl20.1, Sl117.6 and Sl120.0. The author described 5? UTR stress-responsive elements, probably involved in abiotic and biotic stress response. We found in tomato cv Heinz 1706 a fourth intronless gene member, Solyc06g076520 that conserve a 97.9% nucleotide identity with Solyc06g076560. Its promoter carries similar cis stress-responsive elements (ERE,Auxin responsive, GARE, HSE, MYB recognition site and ABRE-like sequence) that may explain fruit developmental and ripening transcript abundance and differential gene expression pattern in RNAseq experiments. A phylogenomic analysisof Solanum species suggests that duplication event in the chromosome 6 region occurred before the split of the ancestor of tomato related species and potato (~7.3 mya). Since then, their collinear arrangement of 5 class I sHsps genes has been possible maintained by natural selection. Nevertheless, in S. lycopersicum cultivars it might have changed due artificial selection.