Tsw gene-based resistance is triggered by a functional RNA silencing suppressor protein of the Tomato spotted wilt virus.
As a result of contradictory reports, the avirulence (Avr) determinant that triggers Tsw gene-based resistance in Capsicum annuum against the Tomato spotted wilt virus (TSWV) is still unresolved. Here, the N and NSs genes of resistance-inducing (RI) and resistance-breaking (RB) isolates were cloned and transiently expressed in resistant Capsicum plants to determine the identity of the Avr protein. It was shown that the NSs(RI) protein triggered a hypersensitive response (HR) in Tsw-containing Capsicum plants, but not in susceptible Capsicum, whereas no HR was discerned after expression of the N(RI) (/) (RB) protein, or when NSs(RB) was expressed. Although NSs(RI) was able to suppress the silencing of a functional green fluorescence protein (GFP) construct during Agrobacterium tumefaciens transient assays on Nicotiana benthamiana, NSs(RB) had lost this capacity. The observation that RB isolates suppressed local GFP silencing during an infection indicated a recovery of RNA silencing suppressor activity for the NSs protein or the presence of another RNA interference (RNAi) suppressor. The role of NSs as RNA silencing suppressor and Avr determinant is discussed in the light of a putative interplay between RNAi and the natural Tsw resistance gene.
Laboratory of Virology, Department of Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Dryas
D
de Ronde
Patrick
P
Butterbach
Dick
D
Lohuis
Marcio
M
Hedil
Jan W M
JW
van Lent
Richard
R
Kormelink
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002212:Capsicum / Q000235:genetics* / Q000276:immunology / Q000821:virology*; D060467:Disease Resistance / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D017343:Genes, Plant / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology / Q000821:virology; D018515:Plant Leaves / Q000821:virology; D034622:RNA Interference; D016415:Sequence Alignment; D017865:Tospovirus / Q000302:isolation & purification / Q000502:physiology*; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism
D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins