Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, USA.
Plant Cell Rep. 2024 May 11;43(6):138. doi: 10.1007/s00299-024-03224-9.
The soybean gene GmSABP2-1 encodes methyl salicylate esterase and its overexpression led to significant reduction in development of pathogenic soybean cyst nematode. Soybean cyst nematode (SCN, Heterodera glycines) is one of the most devastating pests of soybean (Glycine max L. Merr.). In searching for SCN-defense genes, a soybean gene of the methylesterase (MES) family was found to be upregulated in an SCN-resistant soybean line and downregulated in an SCN-susceptible line upon SCN infection. This gene was designated as GmSABP2-1. Here, we report on biochemical and overexpression studies of GmSABP2-1 to examine its possible function in SCN resistance. The protein encoded by GmSABP2-1 is closely related to known methyl salicylate esterases. To determine the biochemical function of GmSABP2-1, a full-length cDNA of GmSABP2-1 was cloned into a protein expression vector and expressed in Escherichia coli. The resulting recombinant GmSABP2-1 was demonstrated to catalyze the demethylation of methyl salicylate. The biochemical properties of GmSABP2-1 were determined. Its apparent Km value was 46.2 ± 2.2 μM for methyl salicylate, comparable to those of the known methyl salicylate esterases. To explore the biological significance of GmSABP2-1 in soybean defense against SCN, we first overexpressed GmSABP2-1 in transgenic hairy roots of an SCN-susceptible soybean line. When infected with SCN, GmSABP2-1-overexpressing hairy roots showed 84.5% reduction in the development of SCN beyond J2 stage. To provide further genetic evidence for the role of GmSABP2-1 in SCN resistance, stable transgenic soybean plants overexpressing GmSABP2-1 were produced. Analysis of the GmSABP2-1-overexpressing lines showed a significant reduction in SCN development compared to non-transgenic plants. In conclusion, we demonstrated that GmSABP2-1 encodes methyl salicylate esterase and functions as a resistance-related gene against SCN.
大豆基因 GmSABP2-1 编码甲基水杨酸酯酶，其过表达导致大豆胞囊线虫发育显著减少。大豆胞囊线虫（SCN，Heterodera glycines）是大豆（Glycine max L. Merr.）最具破坏性的害虫之一。在寻找 SCN 防御基因时，发现一种大豆甲酯酶（MES）家族的基因在 SCN 抗性大豆品系中上调，而在 SCN 易感品系中下调。该基因被命名为 GmSABP2-1。在这里，我们报告了 GmSABP2-1 的生化和过表达研究，以检验其在 SCN 抗性中的可能功能。GmSABP2-1 编码的蛋白质与已知的甲基水杨酸酯酶密切相关。为了确定 GmSABP2-1 的生化功能，将全长 GmSABP2-1 cDNA 克隆到蛋白表达载体中，并在大肠杆菌中表达。结果表明，重组 GmSABP2-1 能催化甲基水杨酸的去甲基化。测定了 GmSABP2-1 的生化特性。其对甲基水杨酸的表观 Km 值为 46.2±2.2μM，与已知的甲基水杨酸酯酶相当。为了探讨 GmSABP2-1 在大豆抵御 SCN 中的生物学意义，我们首先在 SCN 易感大豆品系的 SCN 敏感毛状根中过表达 GmSABP2-1。当感染 SCN 时，GmSABP2-1 过表达毛状根在 J2 阶段后发育的 SCN 减少了 84.5%。为了提供 GmSABP2-1 在 SCN 抗性中的作用的进一步遗传证据，我们产生了过表达 GmSABP2-1 的稳定转基因大豆植株。对 GmSABP2-1 过表达系的分析表明，与非转基因植株相比，SCN 的发育明显减少。总之，我们证明 GmSABP2-1 编码甲基水杨酸酯酶，作为一种与 SCN 抗性相关的基因发挥作用。
