Jilin Provincial Key Laboratory of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, 130033, China.
Transgenic Res. 2022 Apr;31(2):239-248. doi: 10.1007/s11248-022-00298-7. Epub 2022 Feb 8.
Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is the most economically damaging pathogen affecting soybean production worldwide. Host-induced gene silencing provides a promising approach to confer resistance to plant parasitic nematodes. In the present study, we produced stable transgenic soybean plants individually harboring the inverted repeats of three essential H. glycines genes, Hg-rps23, Hg-snb1, and Hg-cpn1, and evaluated their resistance to SCN infection. Molecular characterization confirmed the stable integration of the hairpin double stranded (ds) RNA in host plants. Inoculation assays with SCN race 3 showed significant reduction of female index (FI, 11.84 ~ 17.47%) on the roots of T transgenic plants, with 73.29 ~ 81.90% reduction for the three RNA interference (RNAi) constructs, compared to non-transformed plants (NT, 65.43%). Enhanced resistance to SCN race 3 was further confirmed in subsequent generations (T) of transgenic soybean. Moreover, when inoculated with SCN race 4 which was considered highly virulent to most of soybean germplasms and varieties, transgenic soybean plants also exhibited reduced FIs (9.96 ~ 23.67%) and increased resistance, relative to the NT plants (46.46%). Consistently, significant down-regulation in transcript levels of the Hg-rps23, Hg-snb1, Hg-cpn1 genes were observed in the nematodes feeding on the transgenic roots, suggesting a broad-spectrum resistance mediated by the host-mediated silencing of vital H. glycines genes. There were no significant differences in morphological traits between transgenic and NT soybean plants under conditions with negligible SCN infection. In summary, our results demonstrate the effectiveness of host-induced silencing of essential H. glycines genes to enhance broad-spectrum SCN resistance in stable transgenic soybean plants, without negative consequences on the agronomic performance.
大豆胞囊线虫（SCN， Heterodera glycines Ichinohe）是全球范围内影响大豆生产的最具经济破坏性的病原体。宿主诱导基因沉默为赋予植物寄生线虫抗性提供了一种很有前途的方法。在本研究中，我们分别产生了稳定转化的大豆植株，这些植株单独含有三个必需的 H. glycines 基因（Hg-rps23、Hg-snb1 和 Hg-cpn1）的反向重复序列，并评估了它们对 SCN 感染的抗性。分子特征确认了发夹双链（ds）RNA 在宿主植物中的稳定整合。用 SCN 第 3 生理小种进行接种试验表明，在 T 转基因植株的根部，雌性指数（FI，11.8417.47%）显著降低，而三个 RNA 干扰（RNAi）构建体的 FI 降低了 73.2981.90%，与非转化植株（NT）相比（65.43%）。在随后的几代（T）转基因大豆中进一步证实了对 SCN 第 3 生理小种的增强抗性。此外，当接种被认为对大多数大豆种质和品种具有高度毒性的 SCN 第 4 生理小种时，与 NT 植株相比，转基因大豆植株也表现出较低的 FI（9.96~23.67%）和增强的抗性。同样，在寄生在转基因根上的线虫中，Hg-rps23、Hg-snb1、Hg-cpn1 基因的转录水平明显下调，表明通过宿主介导的关键 H. glycines 基因沉默介导了广谱抗性。在 SCN 感染可忽略不计的情况下，转基因和 NT 大豆植株在形态特征上没有显著差异。总之，我们的结果表明，通过宿主诱导的必需 H. glycines 基因沉默来增强稳定转化的大豆植株对广谱 SCN 抗性是有效的，并且对农业表现没有负面影响。
