Temporal expression of three conserved putative microRNAs in response of Citrus × Limon to Xanthomonas citri subsp. citri and Xanthomonas fuscans subsp. Aurantifolii

Citrus canker is a widespread bacterial disease that severely affects Citrus production. Xanthomonas spp. are the causative agents of the disease, which manifests as necrotic pustule-like lesions on the plant organs including leaves, fruits, and stems. MicroRNAs (miRNAs) are well-established post-transcriptional gene expression regulators that modulate plant responses during many stress conditions. Accordingly, some bacteria-responsive miRNAs have been shown to have regulatory functions in the plant-pathogen interactions. In this study, we successfully assessed the expression patterns of three conserved miRNAs: miR159, miR167, and miR398, in Citrus × Limon (lemon) infiltrated with Xanthomonas strains A and C using stem-loop RT-qPCR. Our results showed that the expressions of miR159 and mir167 have nearly similar patterns upon inoculations, while the expression of miR398 remains constantly up-regulated after an early induction.