P-253 - Plant protein SUO modulates potyviral translation

Monday, July 14, 2025

13:30 - 15:15

Location: Confex Hall 3

Plant-virus Interactions (incl. Viromes, Evolution & Vectors)

Presenting Author(s)

PD

Pinky Dutta

Doctoral Student/researcher
University of Helsinki
Helsinki, Uusimaa, Finland

Author(s)

MP

Maija Pollari

University lecturer
University of Helsinki
Helsinki, Uusimaa, Finland
KM

Kristiina Mäkinen

Professor of Plant Pathology
University of Helsinki
Helsinki, Uusimaa, Finland

Transition from juvenile to adult stage in plants is controlled by a widely conserved protein, SUO, via the miRNA-mediated translational repression pathway. SUO regulates the protein synthesis of squamosa protein like (SPLs) transcription factor family members, which participate in development and defence roles in plants. suo1 is a loss-of-function mutant shown to reduce the activity of miR156/157 and AGO1 and to increase abscisic acid (ABA) sensitivity. To investigate if SUO-implicated translational repression could modulate potyviral infection, we infected suo1 Arabidopsis thaliana (At) and suo knock-down Nicotiana benthamiana (Nb) with turnip mosaic virus (TuMV) and potato virus A (PVA), respectively. We observed that the deficiency of SUO negatively affects potyviral protein accumulation without significantly affecting the abundance of viral RNA (vRNA). Additionally, we used polysome profiling in Nb, to show that the decrease in PVA translation is due to reduced association of vRNA with host polysomes. Furthermore, we observed an increase in PVA translation and vRNA abundance upon heterologous expression of AtSUO with PVA in Nb. Based on our results, we put forward a conjecture suggesting that SUO might play a beneficial role during potyviral infection by regulating SPL proteins. We present a testable model where transient suo silencing increases SPL6 protein levels, which subsequently induces anti-viral defence responses, reducing potyviral translation.