Environmental Biotechnology Laboratory, Department of Biotechnology, University of the Western Cape, Bellville, 7535, South Africa.
Plant Omics Laboratory, Department of Biotechnology, University of the Western Cape, Bellville, 7535, South Africa.
Sci Rep. 2023 Aug 21;13(1):13618. doi: 10.1038/s41598-023-40788-0.
Raphanus sativus also known as radish is a member of the Brassicaceae family which is mainly cultivated for human and animal consumption. R. sativus growth and development is negatively affected by heavy metal stress. The metal zirconium (Zr) have toxic effects on plants and tolerance to the metal could be regulated by known signaling molecules such as methylglyoxal (MG). Therefore, in this study we investigated whether the application of the signaling molecule MG could improve the Zr tolerance of R. sativus at the seedling stage. We measured the following: seed germination, dry weight, cotyledon abscission (%), cell viability, chlorophyll content, malondialdehyde (MDA) content, conjugated diene (CD) content, hydrogen peroxide (HO) content, superoxide (O) content, MG content, hydroxyl radical (·OH) concentration, ascorbate peroxidase (APX) activity, superoxide dismutase (SOD) activity, glyoxalase I (Gly I) activity, Zr content and translocation factor. Under Zr stress, exogenous MG increased the seed germination percentage, shoot dry weight, cotyledon abscission, cell viability and chlorophyll content. Exogenous MG also led to a decrease in MDA, CD, HO, O, MG and ·OH, under Zr stress in the shoots. Furthermore, MG application led to an increase in the enzymatic activities of APX, SOD and Gly I as well as in the complete blocking of cotyledon abscission under Zr stress. MG treatment decreased the uptake of Zr in the roots and shoots. Zr treatment decreased the translocation factor of the Zr from roots to shoots and MG treatment decreased the translocation factor of Zr even more significantly compared to the Zr only treatment. Our results indicate that MG treatment can improve R. sativus seedling growth under Zr stress through the activation of antioxidant enzymes and Gly I through reactive oxygen species and MG signaling, inhibiting cotyledon abscission through HO signaling and immobilizing Zr translocation.
萝卜又名莱菔，是十字花科植物，主要供人类和动物食用。重金属胁迫会对萝卜的生长和发育产生负面影响。金属锆（Zr）对植物有毒性，而植物对金属的耐受性可以通过已知的信号分子如甲基乙二醛（MG）来调节。因此，在这项研究中，我们研究了在幼苗期应用信号分子 MG 是否可以提高萝卜对 Zr 的耐受性。我们测量了以下指标：种子发芽率、干重、子叶脱落率（%）、细胞活力、叶绿素含量、丙二醛（MDA）含量、共轭二烯（CD）含量、过氧化氢（HO）含量、超氧阴离子（O）含量、MG 含量、羟自由基（·OH）浓度、抗坏血酸过氧化物酶（APX）活性、超氧化物歧化酶（SOD）活性、醛酮还原酶 I（Gly I）活性、Zr 含量和转运因子。在 Zr 胁迫下，外源 MG 提高了种子发芽率、芽干重、子叶脱落率、细胞活力和叶绿素含量。外源 MG 还导致 MDA、CD、HO、O、MG 和·OH 在 Zr 胁迫下的芽中含量降低。此外，MG 应用导致 APX、SOD 和 Gly I 的酶活性增加，同时在 Zr 胁迫下完全阻止了子叶脱落。MG 处理降低了根和芽中 Zr 的吸收。Zr 处理降低了 Zr 从根到芽的转运因子，而 MG 处理比仅 Zr 处理更显著地降低了 Zr 的转运因子。我们的结果表明，MG 处理可以通过激活抗氧化酶和 Gly I 来改善萝卜幼苗在 Zr 胁迫下的生长，通过 HO 信号抑制子叶脱落，并固定 Zr 的转运。
