ATP-Dependent Binding Cassette Transporter ClABCI6 Promotes the Expression of citrus yellow vein clearing virus via inhibiting salicylic acid pathway

ATP-dependent binding cassette (ABC) transporters are a class of proteins that utilize ATP hydrolysis to actively transport diverse substrates, but the function of ABC transporters in plant antiviral defense remains poorly characterized. In this study, the homologous ABCI6 originate from Citrus spp. showed high evolutionary conservation (higher than 75.82%). The expression of ClABCI6, the ABCI6 homologous gene in Eureka lemon, was significantly increased after citrus yellow vein clearing virus (CYVCV) infection. Further study showed that ClABCI6 located in the chloroplast and interacted with RNA-dependent RNA polymerase domain (He-RdRp) of CYVCV in yeasts. In addition, ClABCI6 promoted the expression of He-RdRp and CYVCV, and inhibited the expression of salicylic acid pathway genes in lemon. This study provides information on the evolution and function of ClABCI6, and reveals its response patterns to CYVCV-infection.