title: A single amino acid at N-terminal region of the 2b protein of cucumber mosaic virus strain m1 has a pivotal role in virus attenuation.
abstract: Host responses to infection by a mild strain of cucumber mosaic virus, termed CMV-m1, were re-examined in several plant species in comparison with those by a severe strain CMV-Y. Mild systemic symptoms were developed on the six plant species inoculated with CMV-m1. Virus titer in the Nicotiana benthamiana plants infected with CMV-m1 was significantly lower than those infected with CMV-Y, although infection by CMV-m1 interfered with further infection by CMV-Y in the plants. Subsequently, the attenuated virulence of CMV-m1 was analyzed by reassortment and recombination analyses between CMV-m1 and CMV-Y RNAs. The results suggested that the 2b protein of CMV-m1 (m1-2b) is involved in the formation of mild symptoms in N. benthamiana. Furthermore, site-directed mutagenesis demonstrated that Thr18 of m1-2b is responsible for formation of mild symptoms. Local RNA silencing suppressor activity of m1-2b was a little lower than that of severe strain CMV-Y. We discuss the relationship between attenuation of CMV-m1 and the features of m1-2b.
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Phoowanarth
authors.initials: P
authors.lastname: Maneechoat
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. Electronic address: minorutk@agr.kyushu-u.ac.jp.
authors.forename: Minoru
authors.initials: M
authors.lastname: Takeshita
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Uenoyama
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Nakatsukasa
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Kuroda
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Naruto
authors.initials: N
authors.lastname: Furuya
authors.affiliation: Laboratory of Plant Pathology, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tsuchiya
mesh_terms: D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D017799:Cucumovirus / Q000235:genetics* / Q000254:growth & development*; D004252:DNA Mutational Analysis; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010935:Plant Diseases / Q000821:virology; D010944:Plants; D012367:RNA, Viral / Q000235:genetics; D016865:Reassortant Viruses / Q000235:genetics / Q000254:growth & development; D059386:Reverse Genetics; D017422:Sequence Analysis, DNA; D019562:Viral Load; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: C404227:2b protein, cucumber mosaic virus; D000596:Amino Acids; D012367:RNA, Viral; D014764:Viral Proteins; D037521:Virulence Factors
keywords: 2b protein; Attenuated virus; Cross protection; Cucumber mosaic virus; Mild strain