Metal accumuation in soybean: metallothionein family characterization

PAGANI MA; CARRILLO J; REGGIARDO M; TOMAS M; CAPDEVILA M; BOFILL R; ATRIAN S; ANDREO CS

Potrero de los Funes, San Luis

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, SAIB; 2011

SAIB

Plants produce different types of peptidic defences against heavy metals: phytochelatins?enzymatically synthesized peptides-, metallothioneins (MTs) ?proteins deeply studied in the animal kingdom- and metallohistins ?a new kind of vegetal protein thought to be involved in metal metabolism. Nevertheless, data on the last two systems (polymorphism, regulation, structure and function of these genes and corresponding proteins) in plants are scarce, so the aim of this study is the characterization of the molecular mechanisms involved in metal accumulation in plants of interest in agriculture, such as soybean. In silico analysis of soybean genome and ESTs banks with known MT sequences or motifs has rendered 10 sequences of probable MT genes. Four of these genes, whose sequences codify for the 4 plant MT types described, are currently under studies. All of them are expressed at high levels: MT1, MT2 and MT3 in root, shoot and seeds and MT4 only in seeds. Heterologous expression in S.cerevisiae restores Cd and Cu tolerance, only marginally enhances Zn tolerance, and improves resistance to oxidative stress in MT-null yeast strains. Soybean MTs, purified from E. coli cells cultured in different metal rich media, render better folded polypeptides with Cd and Cu than with Zn. These results point towards a role in metal.