Suberin feruloyl transferase FHT confers the antiviral activity by targeting the coat protein of cucumber green mottle mosaic virus

Abstract Fatty acid ω-hydroxyacid/fatty alcohol hydroxycinnamoyl transferase (FHT) is a key enzyme involved in suberin biosynthesis. The phytohormone abscisic acid (ABA) positively regulates suberin formation by promoting FHT expression, however the role of FHT regulated by ABA in viral infection remains unclear. Immunoprecipitation coupled with mass spectrometry (IP-MS) screening indicated that NbFHT interacting with the coat protein (CP) of cucumber green mottle mosaic virus (CGMMV). This interaction was further confirmed by bimolecular fluorescence complementation (BiFC) assay and co-immunoprecipitation (Co-IP) assays. Quantitative real-time polymerase chain reaction (qPCR) analysis revealed that the NbFHT gene expression was induced during CGMMV infection. Virus-induced gene silencing (VIGS) and overexpression analysis further demonstrated that NbFHT in Nicotiana benthamiana enhances host resistance to CGMMV. Notably, NbFHT interferes with the CGMMV CP self-interaction and promotes CP degradation. Moreover, exogenous ABA treatment significantly stabilized NbFHT and accelerated CP degradation, contributing to the increased resistance to CGMMV. Collectively, this study makes a unique contribution by shedding light on the previously unexplored relationship between the suberin synthesis-related enzyme FHT and ABA during viral infection.