Key Laboratory of the High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China.
Key Laboratory of the High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, PR China; Zhongke Hefei Intelligent Agricultural Valley Co., Ltd, Hefei, PR China.
Plant Physiol Biochem. 2021 Oct;167:921-933. doi: 10.1016/j.plaphy.2021.09.023. Epub 2021 Sep 20.
Karrikinolide (KAR), identified in biochars, has gained research attention because of its significant role in seed germination, seedling development, root development, and abiotic stresses. However, KAR regulation of salt stress in wheat is elusive. This study investigated the physiological mechanism involved in KAR alleviation of salt stress in wheat. The results showed KAR boosted seed germination percentage under salinity stress via stimulating the relative expression of genes regulating gibberellins biosynthesis and decreasing the expression levels of abscisic acid biosynthesis and signaling genes. As seen in seed germination, exogenous supplementation of KAR dramatically mitigated the salt stress also in wheat seedling, resulting in increased root and shoot growth as measured in biomass as compared to salt stress alone. Salt stress significantly induced the endogenous hydrogen peroxide and malondialdehyde levels, whereas KAR strictly counterbalanced them. Under salt stress, KAR supplementation showed significant induction in reduced glutathione (GSH) and reduction in oxidized glutathione (GSSG) content, which improved GSH/GSSG ratio in wheat seedlings. Exogenous supplementation of KAR significantly promoted the activities of enzymatic antioxidants in wheat seedlings exposed to salt stress. KAR induced the relative expression of genes regulating the biosynthesis of antioxidants in wheat seedlings under salinity. Moreover, KAR induced the expression level of K/Na homeostasis genes, reduced Na concentration, and induced K concentration in wheat seedling under salt stress. The results suggest that KAR supplementation maintained the redox and K/Na homeostasis in wheat seedling under salinity, which might be a crucial part of physiological mechanisms in KAR induced tolerance to salt stress. In conclusion, we exposed the protective role of KAR against salt stress in wheat.
卡列基诺内酯（KAR）在生物炭中被发现，因其在种子萌发、幼苗发育、根系发育和非生物胁迫方面的重要作用而引起了研究关注。然而，KAR 对小麦盐胁迫的调节作用尚不清楚。本研究探讨了 KAR 缓解小麦盐胁迫的生理机制。结果表明，KAR 通过刺激调节赤霉素生物合成的基因的相对表达并降低脱落酸生物合成和信号转导基因的表达水平，促进了盐胁迫下种子的萌发率。与单独盐胁迫相比，外源添加 KAR 也显著减轻了盐胁迫对小麦幼苗的影响，导致根和芽的生物量增加。盐胁迫显著诱导内源过氧化氢和丙二醛水平升高，而 KAR 则严格抑制了它们。在盐胁迫下，KAR 补充处理显著诱导还原型谷胱甘肽（GSH）的增加和氧化型谷胱甘肽（GSSG）的减少，从而提高了小麦幼苗中的 GSH/GSSG 比值。外源添加 KAR 显著促进了盐胁迫下小麦幼苗中酶抗氧化剂的活性。KAR 诱导了盐胁迫下小麦幼苗中抗氧化剂生物合成相关基因的相对表达。此外，KAR 诱导了盐胁迫下小麦幼苗中 K/Na 稳态基因的表达水平，降低了 Na 浓度，诱导了 K 浓度。结果表明，KAR 补充处理在盐胁迫下维持了小麦幼苗的氧化还原和 K/Na 稳态，这可能是 KAR 诱导耐盐性的生理机制的重要组成部分。总之，我们揭示了 KAR 对小麦盐胁迫的保护作用。
