The Protein Elicitor Hrip1 Enhances Resistance to Insect and Ahead of Time of Flower Bolting in Arabidopsis thaliana

The elicitor Hrip1 isolated from necrotrophic fungus Alternaria tenuissima, could induce systemic acquired resistance in tobacco to enhance resistance to tobacco mosaic virus. In the present study, we found that Hrip1 was overexpressed in wild type (WT) Arabidopsis thaliana. Our results indicate that the transgenic lines were more resistant to Spodoptera exigua and ahead of time of flower bolting than the WT line. A profiling of transcription assay using digital gene expression profiling was used for transgenic and WT Arabidopsis thaliana. Differentially expressed genes including 40 upregulated and three downregulated genes were identified. In transgenic lines of Hrip1 overexpression, three genes related to Jasmonate (JA) biosynthesis were significantly upregulated, and the JA level was found to be higher than WT. Two GDSL family members (GLIP1 and GLIP4) and pathogen-related gene, which participated in pathogen defense action, were upregulated in the transgenic line of Hrip1 overexpression. Thus, Hrip1 is involved in affecting the flower bolting time and regulating endogenous JA biosynthesis and regulatory network to enhance resistance to larvae.

从死体营养型真菌细极链格孢（Alternaria tenuissima）中分离得到的激发子Hrip1，可诱导烟草产生系统获得性抗性（systemic acquired resistance），增强其对烟草花叶病毒的抗性。本研究将Hrip1基因在野生型（WT）拟南芥（Arabidopsis thaliana）中进行过表达。结果表明，相较于野生型株系，转基因株系对甜菜夜蛾（Spodoptera exigua）的抗性更强，且抽薹时间更早。本研究采用数字基因表达谱（digital gene expression profiling）技术，对转基因与野生型拟南芥开展转录表达分析，共鉴定出43个差异表达基因，其中40个基因上调表达、3个基因下调表达。在Hrip1过表达的转基因株系中，3个与茉莉酸（Jasmonate, JA）生物合成相关的基因显著上调，且转基因株系的内源茉莉酸水平高于野生型。两个GDSL家族成员（GLIP1与GLIP4）以及参与病原体防御的病程相关基因，在Hrip1过表达转基因株系中均出现上调表达。综上，Hrip1可通过影响拟南芥的抽薹时间，调控内源茉莉酸的生物合成及其调控网络，从而增强其对幼虫的抗性。