Selection of an attenuated isolate of Bean yellow mosaic virus for protection of dwarf gentian plants from viral infection in the field

Abstract

An attenuated isolate of Bean yellow mosaic virus (BYMV), designated B-33, that caused barely any mottling on the leaves of gentian plants (Gentiana scabra) was isolated from dwarf gentian plants. Infection with this isolate did not cause severe symptoms in several leguminous plants or in prairie gentian (Eustoma grandiflorum) plants. Dwarf gentian plants that had been infected with an inoculum of partially purified B-33 were propagated vegetatively from cuttings without difficulty. The B-33 isolate could be distinguished from other, more virulent, isolates by comparing symptoms on prairie gentian plants and by examining restriction fragment length polymorphism after reverse transcription and amplification by the polymerase chain reaction. In cross-protection tests, dwarf gentian plants that had been infected with B-33 were protected from infection with the virulent BYMV isolate 35-1. Potted plants that had been inoculated with B-33 grew larger and produced more flowers than unprotected plants. Thus, B-33 is an effective agent for controling mosaic and atrophic diseases caused by BYMV in clonal dwarf gentian plants.

Use of crude sap for one-step RT-PCR-based assays of Bean yellow mosaic virus and the utility of this protocol for various plant?virus combinations

“…An aphidborne virus, Bean yellow mosaic virus (BYMV) causes a mosaic, atrophic disease, which is a serious problem for gentian producers in this prefecture (Uga et al 1998(Uga et al , 2002. An attenuated isolate of BYMV, B-33, was developed to cross-protect plants from more damaging strains of BYMV (Uga et al 2004). Because B-33 is serologically indistinguishable from other isolates of BYMV, we previously developed a reverse transcription-polymerase chain reaction (RT-PCR)-restriction fragment length polymorphism (RFLP) technique to distinguish B-33 from the virulent isolates 35-1 and No.…”

“…4 were obtained from dwarf gentian plants in Saitama Prefecture, Japan (Uga et al 2004). A BYMV-infected gentian leaf (0.1 g) was ground with a flatbottomed 3 ϫ 12 cm test tube in a polyethylene bag (BAG PE 01mm 75 ϫ 130, AS ONE, Osaka, Japan) with 1 ml of extraction buffer (50 mM Tris-HCl, pH 7.5) at room temperature.…”

Selection and discrimination of an attenuated strain of Chinese yam necrotic mosaic virus for cross-protection

“…RT-PCR-RFLP was reported to be a reliable method for evaluating the effi cacy of attenuated strains of several plant viruses (Fuji et al 2000;Nakazono-Nagaoka et al 2005;Uga et al 2004). A comparison of the nucleotide sequences of KM3 and 16 other CYNMV isolates (Kondo et al 2003) revealed that two base substitutions at positions 195 and 1028 are specifi c to KM3 (Fig.…”

“…There has been some research on the use of attenuated strains [e.g., Citrus tristeza virus (Costa and Müller 1980), Japanese yam mosaic virus (Fuji et al 2000;Kajihara et al 2000), and Bean yellow mosaic virus (Uga et al 2004)] to protect perennial plants. Each of these attenuated strains was selected from native isolates occurring naturally in the fi eld.…”

“…There has been some research into the use of attenuated strains to protect perennial plants from viruses that damage economically important crops (Costa and Müller 1980;Fuji et al 2000;Kajihara et al 2000;Uga et al 2004). Kondo et al (2003) reported that cross-protection using an attenuated strain may be useful for controlling CYNMV in the fi eld because the genetic diversity of CYNMV in the main Nagaimo-producing areas of Japan and Korea is very low.…”