Open AccessDifferential roles of geminivirus Rep and AC4 (C4) in the induction of necrosis in Nicotiana benthamiana
Author(s) -
Van Wezel Rene,
Dong Xiangli,
Blake Patrick,
Stanley John,
Hong Yiguo
Publication year - 2002
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1046/j.1364-3703.2002.00141.x
Subject(s) - nicotiana benthamiana , biology , virology , hypersensitive response , agrobacterium , phenotype , virus , gene , genetics , transgene , plant disease resistance
SUMMARY The replication‐associated protein (Rep) of two distinct begomoviruses, the bipartite African cassava mosaic virus (ACMV) and the monopartite Tomato yellow leaf curl virus‐China (TYLCV‐C), elicits a reaction resembling a hypersensitive response (HR), associated with the induction of local necrosis and a systemic burst of hydrogen peroxide production, when expressed from a potato virus X vector in Nicotiana benthamiana . Transient expression of the ACMV Rep after Agrobacterium infiltration of N. benthamiana also triggered an HR‐like response. We have identified a region of the ACMV Rep, referred to as the HR‐like determinant domain (HRD, amino acids 119–179) that is essential for induction of the phenotype. Two additional regions have been identified (amino acids 1–85 and 86–118) that have various effects on the Rep‐mediated phenotype, suggesting that structural constraints are imposed on the functional HRD. The co‐expression of Rep with either AC4 or C4, expressed from overlapping open reading frames, triggers systemic necrosis in infected‐tissues, but AC4 or C4 alone is neither an inducer nor enhancer of the HR‐like phenotype. We propose that ACMV AC4 and TYLCV‐C C4 may counter the plant defence mechanism that is initiated by the Rep‐mediated local HR‐like phenotype.