Coat protein of Chinese wheat mosaic virus upregulates and interacts with cytosolic glyceraldehyde-3-phosphate dehydrogenase,a negative regulator of plant autophagy,to promote virus infection

摘要

Autophagy is an intracellular degradation mechanism involved in antiviral defense,but the strategies employed by plant viruses to counteract autophagy-related defense remain unknown for the majority of the viruses.Herein,we describe how the Chinese wheat mosaic virus(CWMV,genus Furovirus)interferes with autophagy and enhances its infection in Nicotiana benthamiana.Yeast two-hybrid screening and in vivo/in vitro assays revealed that the 19 k Da coat protein(CP19 K)of CWMV interacts with cytosolic glyceraldehyde-3-phosphate dehydrogenases(GAPCs),negative regulators of autophagy,which bind autophagy-related protein 3(ATG3),a key factor in autophagy.CP19 K also directly interacts with ATG3,possibly leading to the formation of a CP19 K–GAPC–ATG3 complex.CP19 K–GAPC interaction appeared to intensify CP19 K–ATG3 binding.Moreover,CP19 K expression upregulated GAPC gene transcripts and reduced autophagic activities.Accordingly,the silencing of GAPC genes in transgenic N.benthamiana reduced CWMV accumulation,whereas CP19 K overexpression enhanced it.Overall,our results suggest that CWMV CP19 K interferes with autophagy through the promotion and utilization of the GAPC role as a negative regulator of autophagy.