Functional characterization of tandem duplicated sHSPs genes in tomato, potato and Arabidopsis genomes

CACCHIARELLI, P.; ARCE, D.P.; TAPIA, E.; PRATTA, G.R.

Posadas

Congreso; VIII Congreso Argentino de Bioinformática y Biología Computacional; 2017

Asociación Argentina de Bioinformática y Biología Computacional

Small heat shock proteins (sHSPs, 12?40 kDa) have been associated with stress tolerance by preventing irreversible aggregation of misfolded proteins. Abiotic stress and developmental changes trigger sHSP gene expression and protein synthesis in Arabidopsis and Solanaceae plants, suggesting the existence of a complex chaperone-network to maintain cellular homeostasis. Previous analysis of tandem duplicated sHSPs identified two cytosolic (Solyc09g015000 and Solyc09g015020) in Solanum lycopersicum cv. Heinz 1706, that map together in chromosome 09. These two sHSPs gene members are highly abundant and strongly induced during tomato heat stress. We evaluated gene copy number and the presence of Solyc09g015000 and Solyc09g015020 orthologs across potato and Arabidopsis genomes. Comparison between tomato and potato indicates a numerical chromosome reorganization effect while comparison between tomato and Arabidopsis indicates a structural chromosome reorganization effect. Seven orthologs were found in S. tuberosum (PGSC v4.03) and one in Arabidopsis (Araport11). Solyc09g015000 is up-regulated during tomato abiotic stress and developmental changes, but the absence of heat shock elements (HSE) in its promoter region, rises the question about its actual importance for triggering sHSP expression. Instead, both Solyc09g015020 and its ortholog AT3G46230 are up-regulated and showed the presence of HSE. Contrarily, four from a total of seven potato sHSPs orthologs are down-regulated after HS and showed the presence of HSEs. The absence of typical HSEs appears to be counterparted by the presence of a specific non-HSE (CTAGA), which was observed in the promoter region of MBF1c in Arabidopsis. MBF1c is a thermotolerance regulator up-regulated during heat shock in Arabidopsis and tomato. Furthermore, to uncover functionality of target sHSP genes in these species, protein protein interactions networks were built, suggesting that a conserved set of genes is associated to heat shock response in the three plant species, independently of duplications and polyploidy.