Expression analysis of new Metallothionein2-like protein under mercury stress in tomato seedling

Abstract

Plants including tomato produce several kinds of chelator proteins such as metallothioneins (MTs) for protection against Hg 2+ toxicity. However, the mechanism of protection from Hg 2+ is not perfectly clear. Hg 2+content subsequently was plateaued from days 1 to 7. Cell death and DNA digestion were not observed in the primary root in the presence of Hg 2+ over the 7 days. The predicted protein sequences of 5 tomato type 2 MT-like (MT2-like) proteins were compared. The coding sequences of accession number Z68185 had no Cys-Cys motif in the N-terminal. However, the Z68185 cDNA genetic recombinant showed high resistance to Hg 2+ in bacteria. In tomato, the expression was observed in the roots, but not in the leaves or stems. mRNA of the MT2-like protein was measured in tomato seedlings exposed to 1 μM Hg 2+ . The expression level did not increase until day 3, but increased expression was observed after day 5. These results suggest that new Metallothionein2-like protein express in root specific and it may trap mercury. Our results indicate that functional identification of an MT2-like protein will be useful for molecular breeding designed to improve plant tolerance to Hg 2+ .

Strontium-induced mineral imbalance, cell death, and reactive oxygen species generation in <i>Arabidopsis thaliana</i>

“…The phytotoxicity of metal ions, such as Fe, Hg, and Bi to dicotyledonous plants have been demonstrated in our previous reports (Nagata 2014, 2015, Nishimura and Nagata 2021. Arabidopsis halleri is a hyperaccumulator plant species able to take up large amounts of several metals.…”

Effect of strontium on the growth, ion balance, and suberin induction in <i>Solanum lycopersicum</i>

“…We studied the phytotoxicity of the metal ions as non-essential nutrients in dicotyledonous plants (Nagata et al 2010, Nagata 2014, 2015. Sr is also a non-essential ion, and its concentration in soil has not been investigated in Japan.…”