A single silent substitution in the genome of Apple stem grooving virus causes symptom attenuation.
Among randomly mutagenized clones derived from an infectious cDNA copy of genomic RNA of Apple stem grooving virus (ASGV), we previously identified a clone, pRM21, whose in vitro transcript (ASGV-RM21) does not induce any symptoms characteristic of the original (wild-type) cDNA clone (ASGV-wt) in several host plants. Interestingly, ASGV-RM21 has only a single, translationally silent nucleotide substitution, U to C, at nucleotide 4646 of the viral genome within open reading frame (ORF) 1. Here, we characterize and verify this unprecedented silent-mutation-induced attenuation of symptoms in infected plants. Northern and Western blot analyses showed that less ASGV-RM21 accumulates in host plants than ASGV-wt. In addition, two more silent substitutions, U to A and U to G, constructed by site-directed mutagenesis at the same nucleotide (4646), also induced attenuated symptoms. This is the first report that a single silent substitution attenuates virus-infection symptoms and implicates a novel determinant of disease symptom severity.
Hirata
Hisae
H
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Lu
Xiaoyun
X
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Yamaji
Yasuyuki
Y
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Kagiwada
Satoshi
S
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Ugaki
Masashi
M
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
Namba
Shigetou
S
Laboratory of Bioresource Technology, Graduate School of Frontier Sciences, The University of Tokyo, 202 Bioscience Bldg, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan.
D015152:Blotting, Northern; D015153:Blotting, Western; D036022:Capsid Proteins / Q000032:analysis; D016679:Genome, Viral; D009154:Mutation; D016366:Open Reading Frames; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D010942:Plant Viruses / Q000235:genetics* / Q000302:isolation & purification; D012328:RNA Viruses / Q000235:genetics* / Q000302:isolation & purification; D012367:RNA, Viral / Q000032:analysis
D036022:Capsid Proteins; D012367:RNA, Viral