ABSTRACT
Insect‐vectored pathogens pose a significant threat to global agriculture. The colonization efficiency of pathogens in vectors plays a central role in these pathosystems, yet studies of the factors that affect this aspect are limited. This study investigates the genetic and microbial symbiont factors influencing the susceptibility of
Diaphorina citri
to
Candidatus
Liberibacter asiaticus (
C
Las), the pathogen causing citrus greening disease (huanglongbing). Through a microbiome Genome Wide Association Study (mGWAS) based on 16S amplicon sequencing and genomic resequencing of 120
D. citri
individuals from six populations, we identified 79 SNPs significantly associated with the relative abundance of
C
Las within insects. Additionally, some of these SNPs were also associated with the relative abundance of
Candidatus
Profftella armature, a key endosymbiont of
D. citri
. SNPs in the regulatory region of gene
Dcitr04g11610.1
led to its overexpression in
C
Las‐susceptible
D. citri
, and
C
Las infection further elevated its expression. Conversely, RNAi knockdown of
Dcitr04g11610.1
reduced
C
Las infection rates and abundance, accompanied by increased abundance of
Profftella
. Phylogenetic analysis revealed
Dcitr04g11610.1
’s high homology to Major Facilitator Superfamily‐type transporter SLC18B1 proteins, suggesting a role in
C
Las polyamine utilization. These findings highlight the importance and potential interplay of insect genetics and symbiotic microbiota in insect‐vectored plant pathogen systems.