Cavallaro Viviana, Maghrebi Moez, Caschetto Mariachiara, Sacchi Gian Attilio, Nocito Fabio Francesco
Dipartimento di Scienze Agrarie e Ambientali-Produzione, Territorio, Agroenergia, Università degli Studi di Milano, Milan, Italy.
Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, Turin, Italy.
Front Plant Sci. 2022 Mar 10;13:837517. doi: 10.3389/fpls.2022.837517. eCollection 2022.
The use of sulfur (S) stable isotopes to study S metabolism in plants is still limited by the relatively small number of studies. It is generally accepted that less S stable isotope discrimination occurs during sulfate (SO ) uptake. However, S metabolism and allocation are expected to produce separations of S stable isotopes among the different plant S pools and organs. In this study, we measured the S isotope composition of the main S pools of rice plants grown under different SO availabilities in appropriate closed and open hydroponic-plant systems. The main results indicate that fractionation against S occurred during SO uptake. Fractionation was dependent on the amount of residual SO in the solution, showing a biphasic behavior related to the relative expression of two SO transporter genes ( and ) in the roots. S isotope separations among S pools and organs were also observed as the result of substantial S isotope fractionations and mixing effects occurring during SO assimilation and plant S partitioning. Since the S stable isotope separations conserve the memory of the physiological and metabolic activities that determined them, we here underline the potential of the S/S analysis for the detailed characterization of the metabolic and molecular processes involved in plant S nutrition and homeostasis.
利用硫（S）稳定同位素研究植物中的硫代谢，仍受限于相关研究数量相对较少。一般认为，在硫酸盐（SO₄²⁻）吸收过程中，硫稳定同位素分馏现象较少发生。然而，预计硫代谢和分配会导致不同植物硫库和器官之间硫稳定同位素的分馏。在本研究中，我们在合适的封闭和开放水培植物系统中，测量了不同SO₄²⁻有效性条件下生长的水稻植株主要硫库的硫同位素组成。主要结果表明，在SO₄²⁻吸收过程中发生了硫分馏。分馏取决于溶液中残留SO₄²⁻的量，呈现出与根中两个SO₄²⁻转运蛋白基因（和）相对表达相关的双相行为。由于在SO₄²⁻同化和植物硫分配过程中发生了大量硫同位素分馏和混合效应，因此在硫库和器官之间也观察到了硫同位素分馏。由于硫稳定同位素分馏保留了决定它们的生理和代谢活动的记忆，我们在此强调硫/硫分析在详细表征植物硫营养和稳态所涉及的代谢和分子过程方面的潜力。
