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New Aspects of Uptake and Metabolism of Non-organic and Organic Iodine Compounds—The Role of Vanadium and Plant-Derived Thyroid Hormone Analogs in Lettuce

2021; Frontiers Media; Volume: 12; Linguagem: Inglês

10.3389/fpls.2021.653168

1664-462X

Sylwester Smoleń, Małgorzata Czernicka, Iwona Kowalska, Kinga Kęska, Maria Halka, Dariusz Grzebelus, Marlena Grzanka, Łukasz Skoczylas, Joanna Pitala, Aneta Koronowicz, Peter Kováčik,

Vanadium and Halogenation Chemistry

The process of uptake and translocation of non-organic iodine (I) ions, I – and IO 3 – , has been relatively well-described in literature. The situation is different for low-molecular-weight organic aromatic I compounds, as data on their uptake or metabolic pathway is only fragmentary. The aim of this study was to determine the process of uptake, transport, and metabolism of I applied to lettuce plants by fertigation as KIO 3 , KIO 3 + salicylic acid (KIO 3 +SA), and iodosalicylates, 5-iodosalicylic acid (5-ISA) and 3,5-diiodosalicylic acid (3,5-diISA), depending on whether additional fertilization with vanadium (V) was used. Each I compound was applied at a dose of 10 μM, SA at a dose of 10 μM, and V at a dose of 0.1 μM. Three independent 2-year-long experiments were carried out with lettuce; two with pot systems using a peat substrate and mineral soil and one with hydroponic lettuce. The effectiveness of I uptake and translocation from the roots to leaves was as follows: 5-ISA > 3,5-diISA > KIO 3 . Iodosalicylates, 5-ISA and 3,5-diISA, were naturally synthesized in plants, similarly to other organic iodine metabolites, i.e., iodotyrosine, as well as plant-derived thyroid hormone analogs (PDTHA), triiodothyronine (T3) and thyroxine (T4). T3 and T4 were synthesized in roots with the participation of endogenous and exogenous 5-ISA and 3,5-diISA and then transported to leaves. The level of plant enrichment in I was safe for consumers. Several genes were shown to perform physiological functions, i.e., per64-like , samdmt , msams5 , and cipk6.