背景:dririgent(DIR)基因编码蛋白质,这些蛋白质充当植物木质素生物合成的关键调节剂。在茄科物种中,DIR基因家族成员与植物生长发育密切相关,在应对各种生物和非生物胁迫中起着关键作用。在茄科物种中,分析DIR基因家族和在各种病原体胁迫下的表达谱将具有重要的应用意义。
结果:根据其各自的基因组序列,共鉴定了57种烟草NtDIR和33种马铃薯StDIR。烟草中DIR基因的系统发育分析,马铃薯,茄子和拟南芥揭示了三个不同的亚组(DIR-a,DIR-b/d和DIR-e)。基因结构和保守基序分析表明,烟草和马铃薯DIR基因的外显子/内含子组织和蛋白质基序高度保守,尤其是在同一个亚家族的成员中.共8对串联重复基因(烟草中的3对,马铃薯中的5对)和13对节段重复基因(烟草中的6对,根据基因重复事件的分析鉴定了马铃薯中的7对)。DIR启动子的顺式调节元件参与激素反应,应激反应,昼夜节律控制,胚乳表达,和分生组织表达。生物胁迫下的转录组数据分析揭示了DIR基因家族成员对病原体的不同反应模式,表明它们的功能分歧。接种青枯雷尔氏菌(Ras)96小时后,烟草幼苗表现出典型的烟草青枯病症状。对11个选定的NtDIR基因的qRT-PCR分析显示出响应于细菌病原体Ras感染的差异表达模式。使用392278线的马铃薯作为材料,马铃薯晚疫病的典型症状表现在致病疫霉感染下的幼苗叶片上。5个选择的StDIR基因的qRT-PCR分析显示响应于病原体感染的上调。值得注意的是,三个成簇基因(NtDIR2、NtDIR4、StDIR3)对病原体感染表现出强烈的反应,强调它们在抗病中的重要作用。
结论:全基因组鉴定,进化分析,烟草和马铃薯中对各种病原体感染的DIR基因的表达谱为这些基因在各种胁迫条件下的作用提供了有价值的见解。我们的结果可以为病原体感染条件下DIR基因家族的进一步功能分析提供基础。
BACKGROUND: The dirigent (DIR) genes encode proteins that act as crucial regulators of plant lignin biosynthesis. In Solanaceae species, members of the DIR gene family are intricately related to plant growth and development, playing a key role in responding to various biotic and abiotic stresses. It will be of great application significance to analyze the DIR gene family and expression profile under various pathogen stresses in Solanaceae species.
RESULTS: A total of 57 tobacco NtDIRs and 33 potato StDIRs were identified based on their respective genome sequences. Phylogenetic analysis of DIR genes in tobacco, potato, eggplant and Arabidopsis thaliana revealed three distinct subgroups (DIR-a, DIR-b/d and DIR-e). Gene structure and conserved motif analysis showed that a high degree of conservation in both exon/intron organization and protein motifs among tobacco and potato DIR genes, especially within members of the same subfamily. Total 8 pairs of tandem duplication genes (3 pairs in tobacco, 5 pairs in potato) and 13 pairs of segmental duplication genes (6 pairs in tobacco, 7 pairs in potato) were identified based on the analysis of gene duplication events. Cis-regulatory elements of the DIR promoters participated in hormone response, stress responses, circadian control, endosperm expression, and meristem expression. Transcriptomic data analysis under biotic stress revealed diverse response patterns among DIR gene family members to pathogens, indicating their functional divergence. After 96 h post-inoculation with Ralstonia solanacearum L. (Ras), tobacco seedlings exhibited typical symptoms of tobacco bacterial wilt. The qRT-PCR analysis of 11 selected NtDIR genes displayed differential expression pattern in response to the bacterial pathogen Ras infection. Using line 392278 of potato as material, typical symptoms of potato late blight manifested on the seedling leaves under Phytophthora infestans infection. The qRT-PCR analysis of 5 selected StDIR genes showed up-regulation in response to pathogen infection. Notably, three clustered genes (NtDIR2, NtDIR4, StDIR3) exhibited a robust response to pathogen infection, highlighting their essential roles in disease resistance.
CONCLUSIONS: The genome-wide identification, evolutionary analysis, and expression profiling of DIR genes in response to various pathogen infection in tobacco and potato have provided valuable insights into the roles of these genes under various stress conditions. Our results could provide a basis for further functional analysis of the DIR gene family under pathogen infection conditions.