Bean common mosaic virus and bean common mosaic necrosis virus (Potyviridae)

Authors: Jordan, Ramon; Hammond, John

Submitted to: Encyclopedia of Virology
Publication Type: Book / Chapter
Publication Acceptance Date: 1/17/2020
Publication Date: 4/9/2020
Citation: Jordan, R.L., Hammond, J. 2020. Bean common mosaic virus and bean common mosaic necrosis virus (Potyviridae). Encyclopedia of Virology. https://doi.org/10.1016/B978-0-12-809633-8.21293-4.
DOI: https://doi.org/10.1016/B978-0-12-809633-8.21293-4

Interpretive Summary:

Technical Abstract: Bean common mosaic virus and Bean common mosaic necrosis virus are species within the genus Potyvirus, family Potyviridae, that cause some of the most economically important diseases of legume crops worldwide. Yield losses due to Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) may vary between 6 to 98% depending on the cultivar and time of infection. Both viruses occur essentially wherever bean and cowpea (including Phaseolus, Vicia, Vigna), lupin (Lupinus), pea (Pisum), peanut (Arachis), and soybean (Glycine) are grown; they are transmitted by aphids in a non-persistent manner, and also seed-transmitted. Isolates of BCMV and BCMNV can be differentiated into eight pathotypes based on their reactions on differential bean cultivars. BCMV was first reported from the US in 1917, and the associated disease initially known as bean mosaic. It was renamed bean common mosaic in 1934 to differentiate it from bean yellow mosaic, caused by Bean yellow mosaic virus (BYMV), another potyvirus. Several pathotypes or strains of BCMV were distinguished in the 1970s by differential reactions of a number of bean cultivars, and in the early 1980s strains were further divided by serology into serotype A and serotype B. Serogroup A isolates were also biologically differentiated by temperature-insensitive induction of necrosis in bean cultivars carrying the dominant I gene. Peptide profiling of the coat protein (CP) and sequence analysis of the CP gene and 3'-untranslated region (UTR) demonstrated that the serotypes represented distinct viruses. Serotype A became known as bean common mosaic necrosis virus, while serotype B retains the name BCMV. BCMV and BCMNV are typical potyviruses with non-enveloped flexuous virions, 12–15 nm wide, and 847–886 nm (BCMV) or 810–818 nm (BCMNV) long. Virions are composed of one single-stranded RNA of c. 9,600 nt for BCMNV and c. 10,000 nt for BCMV, encapsulated in 1,700–2,000 subunits of a single coat protein (CP) species of c. 30 kDa for BCMNV and c. 33 kDa for BCMV. Complete genome sequences support the distinction between BCMV and BCMNV proposed using CP sequences and peptide profiles. BCMV- and BCMNV-specific polyclonal antisera, monoclonal antibodies, and reverse transcription-polymerase chain reaction (RT-PCR) primers have been utilized to detect, differentiate, and characterize these viruses in infected plants. BCMV and BCMNV can be eradicated by eliminating susceptible genotypes and planting only resistant varieties; ‘virus-tested’ certified seed can be used as an effective means to control these two viruses.