Details

Autor(en) / Beteiligte

• Owens, R. A
• Thompson, S. M
• Kramer, M

Titel

Identification of neutral mutants surrounding two naturally occurring variants of Potato spindle tuber viroid

Ist Teil von

• Journal of general virology, 2003-03, Vol.84 (3), p.751-756

Ort / Verlag

England: Soc General Microbiol

Erscheinungsjahr

2003

Quelle

MEDLINE

Beschreibungen/Notizen

• 1 Molecular Plant Pathology Laboratory, USDA/ARS,Beltsville, MD 20705, USA 2 Biometrical Consulting Service, USDA/ARS,Beltsville, MD 20705, USA Correspondence Robert Owens owensr{at}ba.ars.usda.gov Single point mutations in the pathogenicity domain of Potato spindle tuber viroid (PSTVd) can have a dramatic effect on disease expression, and only three substitutions are required for the spontaneous conversion of the type strain PSTVd-Intermediate to the rapidly replicating, highly pathogenic variant RG1 (Gruner et al ., Virology 209 , 60–69, 1995). To identify available evolutionary pathways linking these two variants, we mutagenized five positions in an infectious cDNA copy of PSTVd-Intermediate and screened the resulting mixture of 768 sequences for neutral or near-neutral mutants. Numerical simulations based on the bioassay data indicate that the 23 variants recovered represent >80 % of all such sequences. RG1 was the only naturally occurring variant recovered, and the overall pattern of sequence changes observed indicates that PSTVd-Int occupies a comparatively steep peak within the fitness landscape.