Lemon zinc finger protein ClSUP induces the accumulation of reactive oxygen species and inhibits citrus yellow vein-clearing virus infection via interactions with ClDOF3.4

Citrus yellow vein-clearing virus (CYVCV) is an increasing threat to
citrus cultivation. Notably, the role of zinc finger proteins (ZFPs) in
mediating viral resistance in citrus plants is unclear. In this study, we
demonstrate that ZFPs ClSUP and ClDOF3.4 enhance citrus
defense responses against CYVCV in Eureka lemon. ClSUP
interacted with the coat protein (CP) of CYVCV to reduce CP accumulation
and inhibit its silencing suppressor function. Overexpression of
CISUP triggered reactive oxygen species (ROS) and
salicylic acid (SA) pathways, and enhanced resistance to CYVCV
infection. In contrast, ClSUP-silencing resulted in
increased CP accumulation and down-regulated ROS and SA-related genes.
ClDOF3.4 interacts with ClSUP
to facilitate its interactions
with CP. Furthermore, ClDOF3.4 synergistically
regulated the accumulation of ROS and SA with ClSUP and
accelerated the down-regulation of CP accumulation. Transgenic
plants co-expressing ClSUP and ClDOF3.4 remarkedly decrease the
CYVCV. These findings provide a new reference for
understanding the interaction mechanism between the host and CYVCV.