Expression analysis of the catalase isoforms in tomato plants

SOSSI ML; DI PAOLO V; RÉ M; VALLE E

Rosario

Congreso; Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Catalases are one of the major systems for the enzymatic removal of hydrogen peroxide in plants. Plant catalases are tetramers of Fe-heme containing polypeptides. Higher plants may simultaneously express homotetrameric and heterotetrameric isoforms. In most plants three catalase genes have been identified. However, in tomato four genes have been found: cat1, cat2, er60 and cat3, being the latter identified in our lab. In order to elucidate the specific functions of catalase isoforms in tomato, enzyme activity, isoform profile employing activity gels and westerns, and gene expression in different parts of Solanum Lycopersicum plant (cv. Micro-Tom) were investigated, under normaland stress conditions. The catalase activity and the isoform pattern were different in the various parts of the plant. Also it was found that cat genes were expressed in different proportion in the different parts of the plant. This analysis allowed the classification of the tomato catalases according the classification based on the expression pattern and functional analyses established by Willekens. A phylogenetic tree including the tomato catalases supported this classification. These results showed that the different isoforms may contribute to alleviate oxidative stress under different conditions, probably displaying non-redundant functions.