柑橘黄龙病寄主长春花内生细菌的分离及功能鉴定

Isolation, identification and basic function analysis of plant associated bacteria from huanglongbing's host plant-Catharanthus roseus

【目的】感柑橘黄龙病长春花植株与健康长春花植株不同部位内生细菌菌群结构及功能对柑橘黄龙病菌与长春花内生细菌的相关性研究提供理论基础。【方法】利用兼性厌氧可培养技术以及植物内生菌功能特性分析相结合的方法。【结果】分别从感病和健康长春花叶、茎、根的组织中分离获得67株内生细菌,与GenBank中29种细菌的相似性达到97%-100%。其中短小杆菌属(Curtobacterium sp.)、欧文氏菌属(Erwinia sp.)、蜡样芽胞杆菌(Bacillus cereus)为感病长春花内生细菌的优势菌群,鞘胺醇单胞菌属(Brevundimonas sp.)、芽胞杆菌属(Bacillus sp.)为健康长春花内生细菌的优势菌群;马胃葡萄球菌(Staphylococcus equorum)为两者的共同优势菌群。29种内生细菌进行功能分析,其中6株内生细菌至少具有4种功能特性,分属于马胃葡萄球菌、苏云金芽孢杆菌、巨大芽孢杆菌、短小杆菌属、摩氏摩根菌(Morganella morganii)及溶杆菌属(Lysobacter sp.)5个属。【结论】感病与健康长春花植株中均含有丰富的内生细菌且差异较大,黄龙病菌的存在改变了长春花原有内生细菌的菌群结构。通过分析菌群的差异,有望找到与柑橘黄龙病菌生长相关的菌种。

[Objective] The healthy and huanglongbing-affected Catharanthus roseus under manual-grafting condition were used as materials for research. The endophytic bacterial community structure and function of different parts of healthy and huanglongbing-affected Catharanthus roseus were analysisied, which provided a basis theoretical foundation for correlative study between citrushuanglongbing and Catharanthus roseus endophytic bacterial. [Methods] The endophytic bacterial communities were analysised based on the method of facultative anaerobic culture techniques compared with endophytic bacteria features analysis. [Results] The endophytic bacteria were isolated from sterilized-surface midribs of leaves and phloems, which from stems and roots. With the method of artificial anaerobic culturing, 67 strains were obtained and identified as 29 genera based on the blast results of 16S rDNA. The dominant bacterial population of diseased and healthy C. roseus were mainly came from Curtobacterium sp., Erwinia sp., Bacillus cereus, Brevundimonas sp. and Bacillus sp., While, the common dominant population of both diseased and healthy C. roseus was belonged to Staphylococcus equorum. Performing the methods of physiological and biochemical identification, total of 6 bacterial isolates showed a minimum of four traits related to indole acetic acid （IAA） synthesis, nitrogen （N） fixation and siderophore production, production of 1-amino-cyclopropane-1-carboxylate deaminase, production of antibiotic, amylolysis and protease activity were characterized. Dominant isolates were characterized as 6 genera by functional analysis： Staphylococcus equoru subsp., Bacillus subtilis, Bacillus megaterium, Curtobacterium sp., Morganella morganii, and Lysobacter sp.. These traits may be involved in HLB-affected C. roseus. [Conclusion] The results of bacterial community of the identified endophytic bacteria of Catharanthus roseus and their functional analysis showed the potential role on biological control of HLB pathogen.