Abstract
ABSTRACT
The leaf‐mining insect
Tuta absoluta
is a highly destructive pest that deploys candidate effector proteins to modulate host defences; however, the molecular mechanisms underlying this manipulation remain poorly understood. In this study, we characterise TaCYPE1, a predicted secreted cyclophilin‐like effector, and demonstrate its role in promoting insect virulence. Transient expression of TaCYPE1 in
Nicotiana benthamiana
suppresses pattern‐triggered immunity (PTI), including INF1‐induced cell death, reactive oxygen species (ROS) burst, and defence‐related gene expression. Notably, this immune suppression occurs independently of the conserved peptidyl‐prolyl cis‐trans isomerase (PPIase) activity of TaCYPE1. Stable overexpression of TaCYPE1 in tomato increases host susceptibility and enhances larval feeding, confirming its virulence function in a crop host. Mechanistically, TaCYPE1 physically interacts with host glycine‐rich RNA‐binding proteins (GR‐RBPs), including SlRBP1 in tomato and NbRBGA in
N. benthamiana
, the latter contributes positively to selected immune responses and anti‐herbivore defence. Domain‐mapping analyses reveal that TaCYPE1 interacts with the conserved RNA‐recognition motifs (RRMs) of GR‐RBPs, and similar interactions are observed among GR‐RBP homologues in solanaceous plants. Collectively, our findings identify TaCYPE1 as a virulence‐associated factor that attenuates plant immunity through targeting GR‐RBP‐mediated regulatory processes, revealing a previously unrecognised layer of post‐transcriptional modulation in plant–insect interactions.