The Rep gene of Beet curly top Iran virus represents a pathogenicity factor and together with C1 induces hypersensitive response in plants

Autor/in: Eini, O., S. Ebrahimi, M. Varrelmann
Jahr: 2022
Zeitschrift: Tagungsband 54. Jahrestagung des DPG Arbeitskreises Viruskrankheiten der Pflanzen. Dossenheim, Hybrid, 21.- 22.03.2022.
Seite/n: 20

Published in Projekt Additional publications of the department phytopathology / Abteilung Phytopathology

Abstract

Beet curly top Iran virus (BCTIV) is a member of the genus Becurtovirus (Family Geminiviridae) with a circular single-strand DNA genome. BCTIV causes leaf curling and vein swelling symptoms in plants. However, the potential pathogenicity factor/s in BCTIV is not known. This study presents characterization of complementary sense transcripts of BCTIV and the viral factors in directing the pathogenicity and hypersensitive response (HR) in Nicotiana benthamiana plants. In both virus free and viral systemic infection, splicing of the complementary transcripts was observed. Expression of BCTIV genes in N. benthamiana using the tobacco rattle virus (TRV)-based vector showed that Rep is the main pathogenicity factor which causes the typical viral leaf curling symptoms. In addition, the V2 and C1 genes caused a mild leaf curling, thickening and asymmetric leaves, while the V1, V3 and C2 genes had no effect on the plant phenotype. Transient expression of individual viral genes showed that both the C1 and Rep genes trigger a HR response in N. benthamiana. A higher expression of HR marker genes, harpin-induced 1 (Hin1) and hypersensitivity-related (Hsr203JI), supported the role of C1 and Rep in HR response in plants. It is concluded that BCTIV Rep is the main pathogenicity factor and together with C1 gene trigger HR response in plants.

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