Characterization of the microbial community structure in Candidatus Liberibacter asiaticus-infected citrus plants treated with antibiotics in the field

BMC Microbiology

Research Article

Ying Guo¹  Charles A Powell¹  Muqing Zhang²  Lesley Benyon³  Yongping Duan³ 

[1] Indian River Research and Education Center, IFAS-UF, 34945, Fort Pierce, FL, USA;Indian River Research and Education Center, IFAS-UF, 34945, Fort Pierce, FL, USA;USDA-ARS, US Horticultural Lab, 34945, Fort Pierce, FL, USA;State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, 530004, Guangxi, China;USDA-ARS, US Horticultural Lab, 34945, Fort Pierce, FL, USA;

关键词: Bacterial Community;    Antibiotic Treatment;    Endophytic Bacterium;    Oxytetracycline;    Sampling Time Point;   

DOI  :  10.1186/1471-2180-13-112

 received in 2012-09-27, accepted in 2013-05-20,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundHuanglongbing (HLB) is a worldwide devastating disease of citrus. There are no effective control measures for this newly emerging but century-old disease. Previously, we reported a combination of Penicillin G and Streptomycin was effective in eliminating or suppressing the associated bacterium, ‘Candidatus Liberibacter asiaticus’ (Las).ResultsHere we report the bacterial composition and community structure in HLB-affected citrus plants during a growing season and while being treated with antibiotic combinations PS (Penicillin G and Streptomycin) and KO (Kasugamycin and Oxytetracycline) using the Phylochip™ G3 array. Both antibiotic treatments resulted in significantly lower Las bacterial titers (Pr<0.05) and hybridization scores. Of the 50,000+ available operational taxonomic units (OTUs) on PhyloChip™ G3, 7,028 known OTUs were present in citrus leaf midribs. These OTUs were from 58 phyla, of which five contained 100 or more OTUs, Proteobacteria (44.1%), Firmicutes (23.5%), Actinobacteria (12.4%), Bacteroidetes (6.6%) and Cyanobacteria (3.2%). In the antibiotic treated samples, the number of OTUs decreased to a total of 5,599. The over-all bacterial diversity decreased with the antibiotic treatments, as did the abundance of 11 OTUs within Proteobacteria, Firmicutes, Bacteroidetes and Planctomycetes. Within the Proteobacteria, ten OTUs representing the class γ-proteobacteria increased in abundance after four months of treatment, when the Las bacterium was at its lowest level in the HLB-affected citrus field plants.ConclusionsOur data revealed that Proteobacteria was constantly the dominant bacterial phylum recovered from citrus leaf midribs, with the α-proteobacterial and the γ-proteobacterial classes vying for prevalence. In addition, the level of bacterial diversity found in the leaf midribs of field citrus was greater than previously described. Bacterial cells in close proximity may be able to modify their microenvironment, making the composition of the microbial community an important factor in the ability of Las to cause HLB progression. A low Las level was seen as an annual fluctuation, part of the bacterial population dynamics, and as a response to the antibiotic treatments.

【 授权许可】

Unknown   
© Zhang et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.