Characterization of physiological and molecular processes associated with potato response to Zebra chip disease.

Transcriptional analyses identified molecular mechanisms associated with the response of leaf and root potato tissues to ' Liberibacter solanacearum' (Lso) infection, presumptive causal agent of zebra chip disease (ZC). Putative Lso infection affected several host processes including defense response-, regulation-, starch metabolism- and energy production-related processes. Interestingly, while proteinase inhibitors were strongly upregulated in leaf tissues, a concomitant downregulation was observed in root tissues. Quantitative polymerase chain reaction (qPCR) analysis suggests that alternative splicing might play a role. Furthermore, the transcriptional expression of redox homeostasis-related genes, including superoxide dismutase, showed the most inconsistent response to Lso in leaf and root tissues, highlighting potential targets of Lso susceptibility. Additionally, a net increase in gene expression in ZC-affected tissues despite the concomitant downregulation of photosynthesis-related processes, suggests a putative Lso-mediated low resource-use-efficiency. Subsequent nutritional analyses revealed a hypothesized Lso-mediated increase in nutrient accumulation, particularly a 210 and 108% increases in the potassium concentration of ZC-affected leaf and root tissues, respectively, suggesting an important role for potassium in ZC pathophysiology. This study highlights insights of above and below ground tissues in molecular and physiological aspects associated with potato response to ZC.