藜麦及其祖先二倍体NAC基因的进化与胁迫应答

Evolution characteristics and transcriptional responses to multiple stresses of NAC genes in Chenopodium quinoa and its ancestral diploid species

NAC是一类广泛参与调控植物在生物和非生物胁迫下防御应答的转录因子.基于系统的比较基因组学研究方法,对藜麦Chenopodium quinoa的NAC基因进行进化与多个生物和非生物逆境下的应答研究.在藜麦C.quinoa、祖先二倍体Chenopodium pallidicaule和Chenopodium suecicum基因组中分别共鉴定得到106、54和54个NAC基因.染色体定位数据表明藜麦基因组中18个NAC基因涉及串联倍增事件.3个物种NAC基因的系统进化树证明藜麦基因组中存在NAC基因的倍增与丢失.藜麦分别和C.pallidicaule和C.suecicum之间同源基因组模块的对应数目关系进一步证明藜麦保留了相当数量的祖先二倍体NAC基因,是其NAC基因倍增的主要动力.此外,藜麦NAC基因在干旱、高温、盐、低磷胁迫和GCFSV侵染下的表达模式被阐明;大量NAC基因被显著地诱导表达,推测其参与了藜麦在生物和非生物胁迫下的防御应答反应.本研究结果为藜麦的遗传育种提供了优良的候选NAC基因.(图7参26)

NAC transcription factors widely participate in plant defense mechanisms against biotic and abiotic stresses. In our study, based on systematic bioinformatics methods, the evolutionary characteristics and transcriptional responses under multiple biotic and abiotic stresses were analyzed in NAC genes of Chenopodium quinoa. In total, 106, 54, and 54 NAC genes were identified in C. quinoa and its ancestral diploid species Chenopodium pallidicaule and Chenopodium suecicum. Chromosome location data indicated that 18 NAC genes in C. quinoa were involved in tandem duplication events. The phylogenetic tree of NAC genes of the three Chenopodium species demonstrated that gene duplication and loss occurred in C. quinoa. The number of relationships of syntenic genomic regions between C. quinoa, C. pallidicaule, and C. suecicum further proved that the reservation of substantial NAC genes from ancestral diploid species was the main source of gene duplication in C. quinoa. Under drought, heat, salt, and low Pi stresses and GCFSV infection, the expression profiles of many NAC genes in C. quinoa showed significant up-or down-regulation. These NAC genes may be involved in defense against various stressors. Our results provide NAC gene candidates for further genetic breeding of C. quinoa.