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A bacterial plant pathogen employs the metabolism of its insect vector to fulfill its nutritional and energetic needs

Nabil Killiny: Citrus research and education center, IFAS, University of Florida

<div>Transmission of phyto-pathogenic bacteria by insects involves circulation and propagation of the bacteria within their vectors. The growth of plant-pathogenic bacteria in the hemolymph of their vectors indicate that the hemolymph contains all necessary nutrients. In addition to nutrients, “<em>Candidatus</em> Liberibacter asiaticus” (<em>C</em>Las) uptakes energetic nucleotides, such as ATP, from its vector, <em>Diaphorina citri</em>, using ATP translocase. The goal of this study was to investigate the metabolic changes in <em>D. citri</em> upon infection with <em>C</em>Las. <em>C</em>Las caused a dramatic alteration in <em>D. citri</em> metabolism, particularly in the induction of the glycolysis and the tricarboxylic acid cycles (TCA). In addition, <em>C</em>Las stimulated <em>D. citri</em> to produce more ATP and other energetic nucleotides and inhibited their utilization by the insect, resulting in ATP accumulation. These changes secured the required nutrients and ATP for <em>C</em>Las growth. These metabolic changes resulted in a shorter insect lifespan and altered the feeding behavior. Interestingly, the metabolic alteration was greater in the nymphal stages than in adults. These findings increase our knowledge of insect transmission of the persistent-circulative-propagative type of plant pathogens vectored by insects and provides some insights into the mechanism of colonization of <em>C</em>Las in its vector, <em>D.citri</em>.</div>