GATA8-Mediated Antiviral Defence Is Countered by Tomato Chlorosis Virus-Encoded Pathogenicity Protein p27.

Tomato chlorosis virus (ToCV), a phloem-restricted RNA virus within the genus Crinivirus of the family Closteroviridae, exhibits a broad host range and severely impacts the yield and quality of multiple crops. Viral infection directly alters endogenous phytohormone levels, which are intricately associated with viral mobility, replication, symptom development and defence mechanisms. Previous studies have demonstrated that GATA transcription factors regulate several hormone signalling pathways in plants. In this study, we explored the interaction between ToCV p27 and SlGATA8/NbGATA11. Results indicated that ToCV p27 interacts with an 18-amino-acid at the C-terminus of SlGATA8 and NbGATA11 proteins. Silencing and overexpressing of SlGATA8 revealed its positive role in regulating tomato defence against ToCV infection. Additionally, the interaction redirected SlGATA8's subcellular localisation to plasmodesmata. Furthermore, SlGATA8 promoted the transcriptional expression of SlSnRK2 to regulate the abscisic acid (ABA) signalling pathway. In conclusion, this study confirmed that ToCV p27 impaired the transcriptional activation activity of SlGATA8 through direct interaction, thereby inhibiting the ABA pathway and ultimately facilitating viral infection. This study established a link among virus, GATA family transcription factors and phytohormones, elucidating the molecular mechanism by which ToCV-encoded p27 protein interacts with SlGATA8 to disrupt ABA balance and promote virus infection.