Abstract: NPR1 (non-expressor of PR genes 1) gene is an activator of plant system acquired resistance, and also one of the most important core factors in plant response to pathogen infection, it plays an important role in plant disease resistance. In order to classify the NPR1 gene family and verify the expression pattern of SbNPR1, bioinformatics and real-time fluorescence quantitative analysis (RT-qPCR) were used to analyze the NPR1 gene family and the expression of SbNPR1 expression respectively. The results showed that 5 NPR1 genes, SbNPR1~SbNPR5, were identified in sorghum and the length of amino acid sequence is 480~621 aa, the theoretical molecular weight is between 50.496 81~67.648 06 kDa, theory of isoelectric point is 5.64~6.11. Phylogenetic analysis showed that SbNPR1 was closely related to Sh253P03. Genetic structure analysis showed that the number of exons and introns varied little among members of the family. RT-qPCR analysis showed that the expression of SbNPR1 gene had tissue specificity in sorghum plant. The expression of SbNPR1 was inhibited and induced respectively by the treatment of hormone cyclophosphamide (GR24, 1 μmol·L^-1) and salicylic acid (SA, 1 mmol·L^-1). The expression of SbNPR1 showed a trend of first increasing and then decreasing treated by PEG6000 (20%) and NaCl (250 mmol·L^-1), the relative expression levels were reached the maximum at 0.5 h, and then decreased. However, after treatment with Mannitol (D-Mannitol, 300 mmol·L^-1), the expression level of SbNPR1 gene decreased significantly after 3 h. Sorghum bicolor is treated with pathogen-associated molecular pattern receptors (PAMPs) flg22 (100 nmol·L^-1) and Chitin (8 nmol·L^-1). The expression of SbNPR1 was induced by flg22 and reached to the highest at 12 h after treatment, while its expression was inhibited by Chitin treatment. This study provides a basis for further exploring the role of NPR1 family in regulating sorghum resistance, signal transduction, plant hormones and stress regulation.

Key words: Sorghum, NPR1, gene expression analysis, stress response, PAMPs

摘要： 非表达因子基因(NPR1)是植物系统获得抗性的激活子,也是植物响应病原菌侵染过程中的核心因子之一,在植物抗病性方面发挥着非常重要的作用。为明确高粱NPR1基因家族成员及SbNPR1的表达特性,本研究通过生物信息学及实时荧光定量PCR(RT-qPCR)方法,对高粱NPR1基因家族进行鉴定和表达分析。结果表明,共鉴定到5个高粱NPR1基因SbNPR1~SbNPR5,其氨基酸序列长度介于480~621 aa之间,理论分子量介于50.496 81~67.648 06 kDa之间,理论等电点介于5.64~6.11之间;系统进化分析显示,SbNPR1与甘蔗Sh253P03亲缘关系最近;基因结构分析表明,该家族各个成员之间的外显子和内含子数量差异变化较小;RT-qPCR分析表明,SbNPR1基因在高粱不同器官中的表达具有组织特异性;经激素独脚金内酯(GR24,1 μmol·L^-1)和水杨酸(SA,1 mmol·L^-1)处理后,SbNPR1的表达分别被抑制和诱导;20%的聚乙二醇(PEG6000)和250 mmol·L^-1的NaCl处理下,SbNPR1的表达呈现先升高后降低的趋势,在0.5 h表达量达到最大值,之后下调;而经甘露醇(D-mannitol,300 mmol·L^-1) 处理后,SbNPR1基因表达量在3 h后开始下降;高粱经病原相关分子模式(PAMPs)flg22(100 nmol·L^-1) 和几丁质(Chitin, 8 nmol·L^-1)处理后,SbNPR1受到flg22的诱导表达,在12 h时表达量最高,而在Chitin作用下,SbNPR1的表达受到抑制。本研究为进一步探索NPR1家族在调节高粱抗性、信号转导、植物激素以及胁迫调控等过程中的作用提供了基础。

关键词: 高粱, NPR1, 基因表达分析, 胁迫应答, PAMPs