Abstract:[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 citrus huanglongbing 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.
