尖孢镰孢菌果胶裂解酶基因家族鉴定及侵染表达模式分析

Characterization of pectate lyase gene family in Fusarium oxysporum f. sp. Lycopersici genome and expression mode during inoculation

摘要:

[背景] 番茄枯萎病是番茄生产中常见的土传真菌病害。[目的] 为鉴定番茄枯萎病基因组果胶裂解酶基因家族，明确该基因家族在侵染过程表达模式。[方法] 采用生物信息学方法鉴定了番茄枯萎病尖孢镰孢菌（Fusarium oxysporum f. sp. Lycopersici）基因组内PEL基因家族，并分析了基因结构、染色体定位及三级结构，同时利用荧光定量PCR分析了FoPEL1-16基因在接种番茄根系的表达情况。[结果] 番茄尖孢镰孢菌基因组内PEL基因家族成员有16个。氨基酸序列长度在163-548个氨基酸，信号肽长度在16-21个氨基酸。染色体定位分析表明16个基因在染色体上分布不均，分别定位在 7条染色体上。根据基因结构和保守基序分析结果16个基因可分为4类。进化分析表明该基因家族成员可聚成4支。三级结构预测结果显示同一家族存在相似结构域。荧光定量PCR分析结果表明FoPEL基因在侵染过程表达水平明显上升。[结论] 番茄尖孢镰孢菌基因组内果胶裂解酶以基因家族形式存在，其基因结构存在差异暗示了其功能多样性；FoPEL基因在侵染过程表达明显增强，说明其参与病原菌的致病性。本研究为解析尖孢镰孢菌致病基因功能分析及寄主病原互作提供了重要理论基础。

Abstract:

[Background] Tomato fusarium wilt is a common soil born fungal disease in tomato production. [Objective] To identify pectate lyase gene family members in Fusarium oxysporum f. sp. Lycopersici genome and to clarify the expression mode after inoculation.[Methods] PEL family was identified, and the distribution, physical and chemical properties, gene structure, and tertiary structure prediction of PELs in F. oxysporm f. sp. Lycopersici genome were performed by bioinformatics. Expression mode of FoPEL1−16 in inoculated tomato roots were analyzed by RT-qPCR. [Results] There were 16 FoPELs in F. oxysporm f. sp. Lycopersici genome. The amino acid sequences were 163−548 aa in length with 16−21 aa signal peptides. The FoPEL genes were unevenly distributed on 7 chromosomes. 16 FoPELs were divided into four groups according to gene structure and conserved motifs. Evolutionary analysis showed that FoPELs clustered in four clades. Similar domain structure presented in the same family according to tertiary structure prediction. RT-qPCR analysis showed that FoPEL expression levels significantly increased during inoculation. [Conclusion] The pectate lyase existed in the form of gene family in F. oxysporm f. sp. Lycopersici genome, and the difference of gene structure indicated their function diversity. The expression levels of FoPEL were significantly increased during infection, which indicated that FoPEL was involved in the pathogenicity. The study provided a theoretical basis for pathogenic gene function and plant-pathogen interaction of F. oxysporium.