香蕉枯萎病菌GATA转录因子基因Fnr1的克隆及序列分析

Cloning and sequence analysis of Fnr1 of GATA transcription factor from Fusarium oxysporum f. sp. cubense

【目的】明确香蕉枯萎病菌(Fusarium oxysporum f.sp.cubense)2个生理小种(Foc1和Foc4)GATA转录因子基因(Fnr1)的序列差异,为进一步研究Fnr1在香蕉枯萎病菌致病过程中的作用奠定基础。【方法】根据番茄枯萎病菌2号生理小种(F.oxysporum f.sp.lycopersici race 2)和水稻恶苗病菌(Gibberella fujikuroi)的GATA转录因子的氨基酸序列设计引物,利用重叠延伸PCR和RT-PCR技术分别克隆了香蕉枯萎病菌2个生理小种的Fnr1的全长DAN,并对该基因所编码蛋白进行了氨基酸序列特征、系统发育与保守结构域分析。【结果】2个生理小种的Fnr1(分别命名为F1nr1和F4nr1)DNA片段全长分别为2 967 bp和2 958 bp,开放阅读框架分别为2 727 bp和2 718 bp,分别编码908个和905个氨基酸。F1nr1和F4nr1的预测氨基酸序列相似性为99%,与GenBank中公布的Fusarium spp.GATA转录因子氨基酸序列均有88%~99%相似性。氨基酸序列聚类分析显示,F1nr1和F4nr1与GenBank中已登陆的香蕉枯萎病菌1号生理小种(F.oxysporum f.sp.cubense race 1,Foc1)、尖孢镰刀菌(F.oxysporum)和番茄尖孢镰刀菌2号生理小种(F.oxysporum f.sp.lycopersici race 2)等物种的GATA转录因子蛋白高度同源。蛋白质保守域搜索表明,F1nr1和F4nr1具有GATA结合蛋白的功能域,属于GATA结合蛋白家族的一员。【结论】香蕉枯萎病菌Fnr1基因具备GATA构型转录因子家族的序列特征,推测该基因可能参与调控F.oxysporum f.sp.cubense氮调控相关基因的表达及致病性等。

【Objective】 The objective of this study was to reveal the sequence differences of GATA transcription factor gene(Fnr1) of Fusarium oxysporum f. sp. cubense race 1 and race 4(Foc1 and Foc4),which would provide the theory basis for further study on the function of Fnr1 in pathogenetic process of F.oxysporum f. sp. cubense. 【Method】 Based on the conserved amino acid sequence of GATA transcription factors from F. oxysporum f. sp. lycopersici race 2 and Gibberella fujikuroi, the complete cDNA sequences of Fnr1 from Foc1 and Foc4 were isolated by SOE-PCR and RT-PCR methods, and sequences characterization, phylogenetic clustering and conserved domains on the two predicted proteins of Fnr1 gene were also analyzed, respectively. 【Result】 The results showed that the complete cDNA of Fnr1 from Foc1 and Foc4(named as F1nr1 and F4nr1)were 2 967 bp and 2 958 bp, with the opening reading frame of 2 727 bp and 2 718 bp, encoding a deduced protein of 908-amino acid and 905-amino acid, respectively. The deduced amino acid sequences of F1nr1 and F4nr1 shared 99% similar to each other, and had 88%-99%similarity with the sequences of GATA transcription factor from isolates of Fusarium spp., respectively.Phylogenetic clustering suggested that the amino acid sequences of F1nr1 and F4nr1 showed high similarity to GATA transcription factor homologs of F. oxysporum f. sp. cubense race 1,F. oxysporum and F. oxysporum f. sp. lycopersici race 2 deposited in GenBank. Conservative structure domain analysis showed that F1nr1 and F4nr1 belonged to the GATA protein family, which had a single conversed GATA-type zinc finger domain and a conserved motif at the carboxy terminus. 【Conclusion】 The study showed that Fnr1had the sequence characteristics of GATA gene family in fungi, which meant that Fnr1 might involve in nitrogen regulation gene expression and pathogenicity of F. oxysporum f. sp. cubense.