Summary
‘
Candidatus Liberibacter asiaticus
’ is a fastidious bacterium and a putative agent of citrus greening disease (a.k.a., huanglongbing, HLB), a significant agricultural disease that affects citrus fruit quality and tree health. In citrus, ‘
Ca. L. asiaticus
’ is phloem limited. Lack of culture tools to study ‘
Ca. L. asiaticus
’ complicates analysis of this important organism. To improve understanding of ‘
Ca. L. asiaticus
’–host interactions including parameters that affect ‘
Ca. L. asiaticus
’ replication, methods suitable for screening pathogen responses to physicochemical and nutritional variables are needed. We describe a leaf disc‐based culture assay that allows highly selective measurement of changes in ‘
Ca. L. asiaticus
’ DNA within plant tissue incubated under specific physicochemical and nutritional conditions. qPCR analysis targeting the hypothetical gene CD16‐00155 (strain A4) allowed selective quantification of ‘
Ca. L. asiaticus
’ DNA content within infected tissue. ‘
Ca. L. asiaticus
’ DNA replication was observed in response to glucose exclusively under microaerobic conditions, and the antibiotic amikacin further enhanced ‘
Ca. L. asiaticus
’ DNA replication. Metabolite profiling revealed a moderate impact of ‘
Ca. L. asiaticus
’ on the ability of leaf tissue to metabolize and respond to glucose.