PURPOSE: To provide a gene having a base sequence coding the coat protein gene of isolated barley mild mosaic virus, having each specific molecular weight and restriction enzyme site, useful for e.g. diagnosing barley streaked dwarf disease.
CONSTITUTION: Leaves infected with barley mild mosaic virus (BaMMV) are put into an ice-chilled mortar and incorporated with an ice-chilled 0.1 M citric acid buffer solution (pH 6.8) followed by thoroughly ground, and the resulting liquor is filtered through a gauze; the resulting filtrate is centrifugalized and the supernatant produced is taken and then put to ultracentrifugation to isolate virus particles. Then, RNA is extracted from the virus particles using SDS phenol method, and cDNA is synthesized using the RNA and then put to restriction enzyme treatment and bound to a vector followed by introduction into Escherichia coli and then cloning with a probe; and the resulting positive clone is selected and the DNA is recovered, thus obtaining the objective DNA containing the coat protein gene of BaMMV, 480000±10000 dalton in molecular weight, having a restriction enzyme site of the formula.
HIBINO HIROYUKI
KURODA HISAO
ITO KAZUTOSHI
SAPPORO BREWERIES