Comparative transcriptome analysis of the Eureka lemon in response to Citrus yellow vein virus infection at different temperatures

Abstract

The production of Eureka lemons (Citrus limon) is severely affected by Citrus yellow vein clearing virus (CYVCV). The symptoms induced by CYVCV in Eureka lemons can be reduced at high temperatures. To better understand the molecular mechanisms involved in Eureka lemon responses to CYVCV at high temperatures, chlorophyll content, protective enzyme activities, and chloroplast ultramicrostructure were analyzed in Eureka lemons infected with CYVCV and grown at 25 °C and 37 °C. Chlorophyll content, activity of ascorbate peroxidase (APX), and catalase (CAT) activity were significantly higher in CYVCV-infected lemons grown at 37 °C than at 25 °C. Leaf transcriptomics were also investigated in CYVCV-infected and mock-inoculated Eureka lemons grown at 25 °C and 37 °C. Functional analysis indicated that the differentially expressed genes (DEGs) including resistance-related genes (AGO4, PAL), chlorophyll degradation-related genes (CHL-1, CHL-2), antioxidant enzymes (APX2), and Transcription Factors (TFs) (MYB1R1/s3/12/14/48/111) might have been associated with the reduction in symptoms of CYVCV-infected Eureka lemons grown at higher temperature. This evidence contributes to a theoretical foundation for further study into the molecular basis underlying the interaction between Eureka lemons and CYVCV at high temperatures.