Identification of a compound similar to triiodothyronine in the cells of higher plants

Iodothyronines play an important role in human and animal metabolism; however, their action in plant species is yet to be described. The known beneficial effects of medicinal plants on the function of the thyroid gland suggest the presence of compounds similar to thyroid hormones in plant cells. In this work, we aim to reveal the presence of 3,5,3'-triiodothyronine, the most active representative of iodothyronines, in the cells of higher plants. Using the method of immunoenzyme analysis, it was determined that the roots and stems of bean seedlings contain a compound interacting with a polyclonal serum to 3,5,3'-triiodothyronine. The identified compound is distributed unevenly within the cell: its concentration in the cell nuclei is 7-10 times higher than that in the cytoplasm. Along with bean plants, 8 randomly selected plants belonging to both dicotyledonous and monocotyledonous families were studied. In all the studied species, the presence of an analogue of 3,5,3'-triiodothyronine was determined using the method of immunoenzyme analysis. The use of exogenous iodothyronine - thyroxine (3,5,3',5'-tetraiodothyronine) - for the pre-sowing treatment of wheat seeds reliably improved their germination and led to a significant increase in the root-shoot mass ratio of five-day-old wheat seedlings under the soaking time of 6 and 12 hours. The treatment of wheat seeds with thyroxine led to a significant decrease in the concentration of the identified compound in the stem and root cell nuclei of five-day-old wheat seedlings. The revealed physiological and accumulation effects of exogeus 3,5,3',5' tetraiodothyronine suggest its involvement in gene regulation in the cells of higher plants, similarly to that in animal cells.

higher plants, iodothyronines, thyroxine, intracellular distribution, germination, root-shoot mass ratio