Studies on a Nigerian isolate of banana streak badnavirus: II. Effect of intraplant variation on virus accumulation and reliability of diagnosis by ELISA

Abstract

Monitoring of banana streak badnavirus (BSV) antigens and symptoms in naturally BSV-infected plantain and banana (Musa spp.) plants showed a great variation in symptom expression, distribution and relative concentration of BSV between and within plants. Expression and distribution of symptoms was erratic within individual leaves as well as between different leaves of the same plant. The concentration of BSV antigens detected by triple antibody sandwich enzymelinked immunosorbent assay (TAS-ELISA) varied in different plant parts including leaf lamina, midrib and pseudostem, roots and young 'cigar' leaf. The concentration of BSV antigens was high in symptomatic tissues but was low or below the limits of detection in most asymptomatic tissues. During 'hot dry' seasons when symptoms were not fully expressed, the concentration of BSV antigens in leaf tissues declined drastically, often below the detection limit of TAS-ELISA. These results suggested that for more reliable detection of BSV antigens by TAS-ELISA, it is advisable to index plants using composite tissue samples comprising as many leaves as possible for each plant and collected during cool and/or rainy seasons when symptom expression is generally severe.

Relationship between natural occurrence of banana streak badnavirus and symptom expression, relative concentration of viral antigen, and yield characteristics of some micropropagated Musa spp.

“…Based on the mean incidence of plants with symptoms among parental genotypes (Obino l'Ewai × Calcutta 4; Bobby Tannap × Pisang lilin) and their progenies, Ortiz (1996) suggested that epistatic genetic combinations arising from a specific sexual cross probably induce apparent susceptibility to BSV and symptom expression. However, recent reports suggest that BSV infection in the Musa genotypes used in this and other studies (Ortiz, 1996;Dahal et al, 1998b) probably resulted either from vegetative propagation from infected source plants, or from tissue cultureinduced activation of integrated viral sequences . If so, the BSV isolates described in this study may differ in several respects, including pathogenecity, towards different Musa genotypes.…”

“…The mother plants in plantain fields were sampled randomly and indexed for BSV by immunosorbent electron microscopy (ISEM) (Dahal et al, 1999a) and, whenever possible, BSV-negative plants were used for micropropagation. In some cases mother plants without symptoms, which are normally BSV-negative (Dahal et al, 1998b), were also used. All the micropropagated plants were established in soil as described by Vuylsteke (1989) and kept in a polyethylene tunnel for 2-3 months before being planted in the field.…”

The virulence–transmission trade-off in vector-borne plant viruses: a review of (non-)existing studies

“…These studies estimated withinhost viral accumulation induced by several natural isolates, some inducing mild, some intermediate and some severe symptoms. Several host-virus interactions exhibited positive correlations: PNRSV-Rosa indica (Moury et al 2001), RYMV-Oryza sativa japonica cv Azucena (Fargette et al 2002), CMV infecting Nicotiana glutinosa or N. tabacum (Shi et al 2002) or Cucumis sativus (Banik & Zitter 1990), PRSV infecting Cucurbita pepo or Citrullus lanatus (Pacheco et al 2003), BSV-Musa accuminata (Dahal et al 1998). The relative limitation of these studies comes from the fact that only a few isolates are tested, and, as mentioned previously, symptoms may not be a good proxy for host survival.…”

Highly Efficient Immunodiagnosis of Episomal Banana streak MY virus Using Polyclonal Antibodies Raised Against Recombinant Viral‐Associated Protein

“…Purification of badnaviruses is cumbersome as it occurs at very low concentration in the infected tissues (Dahal et al. ; Thottappilly et al. ).…”