摘要
【目的】明确欧美杨细菌性溃疡病病原菌中双组分信号转导系统LqHK1基因的生物学功能,以阐明该病原菌的致病机制。【方法】采用生物信息学方法鉴定双组分系统LqHK1,利用同源重组方法获得该基因缺失突变体菌株△LqHK1,分析突变体及其互补菌株的生长速率、游动性、生物膜形成、致病性等生物学特性。同时,采用qRT-PCR检测与病原菌游动性相关的基因flgB、flgC、flgE的表达水平,并定量分析接种病原菌后在接种点部位杨树组织内病原菌的DNA含量。【结果】鉴定出病原细菌的双组分系统基因LqHK1,通过同源重组获得缺失突变体△LqHK1。表型分析显示:△LqHK1在1年生107杨茎干上的致病力显著下降;突变体在寄主体内定殖的菌量明显少于野生型菌株;突变体菌株的游动能力比野生型显著降低,游动性相关基因flgB、flgC、flgE在突变体中的表达量显著下降;LqHK1突变体生物膜的形成能力显著降低,生长速率与野生型无显著差异。【结论】LqHK1基因缺失突变体在107杨上的致病能力显著下降,欧美杨细菌性溃疡病病原菌双组分信号转导系统LqHK1基因与病原菌的致病性密切相关。
[ Objective ] Poplar bacterial canker caused by Lonsdalea quercina subsp, populi is a disease, which is serious harm to poplar industry. In this study, the biological function of the LqHK1 gene in L. quercina subsp, populi was investigated to provide viable knowledge for further understanding the pathogenic mechanism of pathogen. [ Method ] The bioinformatics method was used to indentify the two component systems LqHK1. The gene deletion mutant strain △LqHK1 was constructed by homologous recombination. Verifying PCR and Southern blot were used to investigate the biological characteristics of the mutant strains and their complementary strains,such as growth rate, motility, biofilm formation, and pathogenicity. At the same time, qRT-PCR was used to test the expression levels of the motility related genesflgB, flgC, flgE, and quantitatively analyze DNA content of poplar tissue pathogen in the vaccination site after pathogen inoculation. [ Result]The two-component system gene LqHK1 was identified and the deletion mutant △LqHK1 had been obtained by homologous recombination. Phenotypic analysis showed that pathogenicity test on annual poplar branches was significantly less virulent than wide-type, while the complemented mutant HB LqHK1 restored the virulence to the wild-type level. The mutant had significantly less colonization in host than the wild type strain. Mutant strain had reduced swimming ability compared with the wild-type. The motility related genes flgB, flgC, flgE expression significantly decreased in mutant; forming ability LqHK1 mutant biofilms significantly decreased, but the growth rate of LqHK1 mutant strains had no significant difference from wild type. [ Conclusion ] Studies indicate that the bacterial poplar canker Lonsdalea quercina subsp, populi two-component signal transduction system LqHK1 gene is closely related to pathogenpathogenicity.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2017年第4期105-112,共8页
Scientia Silvae Sinicae
基金
国家自然科学基金项目(31400545)
中央高校基本科研业务费专项资金(BLX2013015)
