title: Zinc treatment increases the titre of 'Candidatus Liberibacter asiaticus' in huanglongbing-affected citrus plants while affecting the bacterial microbiomes.
abstract: OBJECTIVE
  Huanglongbing (HLB)-affected citrus often display zinc deficiency symptoms. In this study, supplemental zinc was applied to citrus to determine its effect on Candidatus Liberibacter asiaticus (Las) titre, HLB symptoms, and leaf microbiome.
  
  
  RESULTS
  HLB-affected citrus were treated with various amounts of zinc. The treatments promoted Las growth and affected microbiomes in citrus leaves. Phylochip(™) -based results indicated that 5475 of over 50 000 known Operational Taxonomic Units (OTUs) in 52 phyla were detected in the midribs of HLB-affected citrus, of which Proteobacteria was the most abundant, followed by Firmicutes and Actinobacteria. In comparison, the microbiomes of zinc-treated diseased plants had overall more OTUs with higher amounts of Proteobacteria, but decreased percentages of Firmicutes and Actinobacteria. In addition, more OTUs of siderophore-producing bacteria were present. Only zinc-sensitive Staphylococcaceae had higher OTU's in the diseased plants without zinc treatments.
  
  
  CONCLUSIONS
  Although HLB-affected citrus appear zinc deficient, zinc amendments increased the pathogen levels and shifted the microbiome.
  
  
  CONCLUSIONS
  HLB is currently the most devastating disease of citrus worldwide. Zinc is often applied to HLB-affected citrus due to zinc deficiency symptoms. This study provided new insights into the potential effects of zinc on HLB and the microbial ecology of citrus.
authors.affiliation: State Key Lab for Conservation and Utilization of Subtropical Agro-biological Resources, Guangxi University, Nanning, China.|IRREC-IFAS, University of Florida, Fort Pierce, FL, USA.|USHRL, USDA-ARS, Fort Pierce, FL, USA.
authors.forename: M Q
authors.initials: MQ
authors.lastname: Zhang
authors.affiliation: IRREC-IFAS, University of Florida, Fort Pierce, FL, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.affiliation: IRREC-IFAS, University of Florida, Fort Pierce, FL, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Powell
authors.affiliation: USHRL, USDA-ARS, Fort Pierce, FL, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Doud
authors.affiliation: IRREC-IFAS, University of Florida, Fort Pierce, FL, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: Yang
authors.affiliation: State Key Lab for Conservation and Utilization of Subtropical Agro-biological Resources, Guangxi University, Nanning, China.
authors.forename: H
authors.initials: H
authors.lastname: Zhou
authors.affiliation: USHRL, USDA-ARS, Fort Pierce, FL, USA.
authors.forename: Y P
authors.initials: YP
authors.lastname: Duan
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D002957:Citrus / Q000187:drug effects* / Q000382:microbiology*; D064307:Microbiota / Q000187:drug effects*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D012230:Rhizobiaceae / Q000187:drug effects / Q000502:physiology*; D015032:Zinc / Q000494:pharmacology*
chemical_list: D015032:Zinc
keywords: Candidatus Liberibacter asiaticus; Micronutrient zinc; PhyloChip; citrus huanglongbing; microbial community