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Induction of S-nitrosoglutathione reductase reduces root cadmium uptake by inhibiting Iron-regulated transporter 1

Guan, Mei Yan, Zhu, Ya Xin, Liu, Xing Xing, Jin, Chong Wei
Plant and soil 2019 v.438 no.1-2 pp. 251-262
Arabidopsis, agricultural soils, cadmium, enzymes, gene overexpression, mutants, mutation, polluted soils, roots, transgenic plants
BACKGROUND AND AIMS: Increasing cadmium (Cd) contamination of agricultural soils is a serious problem. Identification of the mechanisms that control Cd uptake by roots is essential if we wish to improve the efficiency of plants in removing Cd from contaminated soils. METHODS: We dissected the role and the mechanism of S-nitrosoglutathione reductase (GSNOR) in regulating root Cd uptake in Arabidopsis plants using GSNOR-related mutants and pharmacological methods. RESULTS: Exposure to Cd stimulated the activity of GSNOR in roots. Both treatment with S-nitrosoglutathione (substrate of GSNOR) in wild-type plants and loss of GSNOR function in gsnor mutants improved expression of IRON-REGULATED TRANSPORTER 1 (IRT1) and increased root Cd uptake, thereby elevating the Cd levels in plants. The opposite patterns were observed in the GSNOR over-expression transgenic plant GSNORᴼᴱ, suggesting a negative regulation of IRT1 expression and Cd uptake by GSNOR. However, both the improvement of Cd uptake owing to S-nitrosoglutathione treatment or GSNOR mutation and the inhibition of Cd uptake due to GSNOR over-expression, could be blocked by loss of function of IRT1 in plants. CONCLUSIONS: We concluded that induction of GSNOR reduced Cd uptake because of its negative regulation of IRT1 in roots, which lowered Cd accumulation in plants.