School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
College of Food Science and Technology, Southwest Minzu University, Chengdu 610041, China.
Plant Physiol Biochem. 2023 Dec;205:108189. doi: 10.1016/j.plaphy.2023.108189. Epub 2023 Nov 13.
Selenite is widely used to increase Selenium (Se) content in cereals, however excessive selenite may be toxic to plant growth. In this study, barley was malted to elucidate the action mechanism of selenite in the generation and detoxification of oxidative toxicity. The results showed that high doses (600 μM) of selenite radically increased oxidative stress by the elevated accumulation of superoxide and malondialdehyde, leading to phenotypic symptoms of selenite-induced toxicity like stunted growth. Barley tolerates selenite through a combination of mechanisms, including altering Se distribution in barley, accelerating Se efflux, and increasing the activity of some essential antioxidant enzymes. Low doses (150 μM) of selenite improved barley biomass, respiratory rate, root vigor, and maintained the steady-state equilibrium between reactive oxygen species (ROS) and antioxidant enzyme. Selenite-induced proline may act as a biosignal to mediate the response of barley to Se stress. Furthermore, low doses of selenite increased the glutathione (GSH) and ascorbate (AsA) concentrations by mediating the ascorbate-glutathione cycle (AsA-GSH cycle). GSH intervention and dimethyl selenide volatilization appear to be the primary mechanisms of selenite tolerance in barley. Thus, results from this study will provide a better understanding of the mechanisms of selenite tolerance in crops.
亚硒酸盐被广泛用于提高谷物中的硒（Se）含量，然而，过量的亚硒酸盐可能对植物生长有毒。在这项研究中，大麦被麦芽化，以阐明亚硒酸盐在氧化毒性的产生和解毒中的作用机制。结果表明，高剂量（600 μM）的亚硒酸盐通过超氧阴离子和丙二醛的积累，自由基极大地增加了氧化应激，导致亚硒酸盐诱导毒性的表型症状，如生长迟缓。大麦通过多种机制耐受亚硒酸盐，包括改变大麦中硒的分布、加速硒的外排以及增加一些必需抗氧化酶的活性。低剂量（150 μM）的亚硒酸盐提高了大麦的生物量、呼吸速率、根活力，并维持了活性氧（ROS）和抗氧化酶之间的稳态平衡。亚硒酸盐诱导的脯氨酸可能作为生物信号，介导大麦对 Se 胁迫的反应。此外，低剂量的亚硒酸盐通过调节抗坏血酸-谷胱甘肽循环（AsA-GSH 循环）来增加谷胱甘肽（GSH）和抗坏血酸（AsA）的浓度。GSH 干预和二甲基硒化物挥发似乎是大麦耐受亚硒酸盐的主要机制。因此，这项研究的结果将更好地理解作物中亚硒酸盐耐受的机制。
