玉米大斑病菌bZIP基因家族鉴定及HT-毒素诱导过程中的表达

The bZIP gene family in Setosphaeria turcica: identification and expression analysis during HT-toxin induction process

摘要:

【目的】碱性亮氨酸拉链(basic leucine zipper,bZIP)蛋白是真核生物中最大且最保守的转录因子之一，参与许多植物病原真菌的生长发育和致病过程。本文旨在对玉米大斑病菌(Setosphaeria turcica) bZIP转录因子进行全基因组鉴定，并探讨它们在HT-毒素诱导过程中的表达规律。【方法】从玉米大斑病菌基因组数据库中筛选鉴定bZIP家族成员，分析其理化性质、保守结构域、亚细胞定位、顺式作用元件、系统进化关系和蛋白质互作网络，利用RNA-seq数据库分析bZIP家族成员在HT-毒素诱导过程中的表达情况。【结果】从玉米大斑病菌基因组筛选到14个bZIP家族成员(StbZIP1−14)，其理化性质差异较大，编码氨基酸226−613个，相对分子量25.24−66.30 kDa，等电点4.66−10.36；亚细胞定位均为细胞核，含有非生物因素胁迫、激素诱导、细胞周期调控和增强子、核心启动子等660个顺式作用响应元件。与11个其他重要植物病原真菌的系统进化分析结果表明，StbZIPs可分为10个类群(groups)，与互隔交链孢霉(Alternaria alternata)的AabZIPs存在明显的共线性关系。分析StbZIPs在HT-毒素诱导过程中的表达情况，发现StbZIP1、StbZIP5、StbZIP7、StbZIP10、StbZIP11与HT-毒素诱导显著相关，其中StbZIP5表达量最高并在HT-毒素诱导21 d和28 d时显著上调。分析了StbZIPs的蛋白质互作网络，提供了3条以StbZIP5为中心的StbZIPs互作途径。【结论】玉米大斑病菌bZIP转录因子家族成员具有显著的理化性质和结构差异、广泛的遗传多样性和显著的功能分化，并在HT-毒素诱导过程中发挥重要的转录调控作用。

Abstract:

[Objective] The basic leucine zipper (bZIP) factors are a group of large and conserved transcription factors in eukaryotes, and they are involved in the growth, development, and infection of pathogenic fungi in plants. This study aims to identify the bZIP transcription factors in the whole genome of Setosphaeria turcica and explore their functions during HT-toxin induction. [Methods] The members of the bZIP family were screened and identified from the genome database of Setosphaeria turcica, and their physicochemical properties, conserved domains, subcellular localization, cis-acting elements, phylogenetic relationship, and protein-protein interaction network were analyzed. The RNA-seq database was used to analyze the expression of bZIP family members during pathogen infection and HT-toxin induction. [Results]Fourteen bZIP family members (StbZIP1–14) were screened from the genome of Setosphaeria turcica, with significant differences in physical and chemical properties. These factors had the lengths of 226–613 aa, relative molecular weights of 25.24–66.30 kDa, isoelectric points of 4.66–10.36, and the subcellular localization in the nucleus. These factors carried 660 cis-acting elements involved in abiotic stress, hormone induction, cell cycle regulation, enhancers, and core promoters. The phylogenetic analysis with 11 other major pathogenic fungi in plants indicated that StbZIPs were clustered into 10 groups and had a clear co-linear relationship with AabZIPs of Alternaria alternata. The expression levels of StbZIP1, StbZIP5, StbZIP7, StbZIP10, and StbZIP11were significantly correlated with HT-toxin induction, among which StbZIP5 had the highest expression level and demonstrated upregulated expression after 21 days and 28 days of HT-toxin induction. The protein-protein interaction network of StbZIPs predicted three StbZIPs interaction pathways centered on StbZIP5. [Conclusion] The members of the bZIP family of Setosphaeria turcica have significant physicochemical and structural differences, extensive genetic diversity, and significant functional differentiation, playing an important role in transcriptional regulation during HT-toxin induction.