Gene Expression Patterns Following Aphid-Mediated Polerovirus Transmission Highlight Differences Between Vector-Host and Host-Virus Interactions

Infection by aphid-transmitted poleroviruses modulates gene expression associated with plant development and defense. This study assessed the gene expression patterns following cotton leafroll dwarf virus (CLRDV) infection in primary and alternate hosts. Two comparisons (CLRDV-infected vs. non-infested and mock-inoculated vs. non-infested) were evaluated to identify differentially expressed genes (DEGs), and to tease out differences in gene expression profiles between aphid feeding and aphid-mediated CLRDV infection in each host. CLRDV infection was characterized by 2079, 1238, 1484, and 1773 DEGs in the primary host cotton, and in alternate hosts hibiscus, okra, and prickly sida, respectively. The number of DEGs upon aphid feeding was less than CLRDV infection in all hosts except okra. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) terms identified DEGs associated with development, defense, and vector fitness influencing compounds (VFICs) in CLRDV-infected plants. Genes associated with phytohormones, photosynthesis, salicylic acid, jasmonic acid, pathogenesis related proteins, heat shock proteins, transcription factors, membrane transporters, terpenoids, carbohydrates, and amino acids were differentially expressed in CLRDV-infected plants and varied between hosts. Few overlapping and numerous unique genes in the above-stated categories were differentially expressed upon aphid feeding and varied between hosts. DEGs associated with signaling pathways, transcription factors, systemic resistance, pathogenesis related proteins, and carbohydrate and amino acid biosynthesis were common between aphid-mediated CLRDV infection and aphid feeding alone. The observed gene expression patterns reiterate that differences in host susceptibility to the virus and/or the vector could differentially influence host defense and development, and vector fitness.