A rapid method for differentiation of Xanthomonas campestris pv. mangiferaeindicae from other Xanthomonads and mango phylloplane inhabitants
✍ Scribed by Dr. Gina M. Sanders; L. Korsten
- Book ID
- 102911636
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 662 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0233-111X
No coin nor oath required. For personal study only.
✦ Synopsis
A rapid method for differentiation of Xanthomonas carnpestris pv. rnangiferaeindicae from other Xanthomonads and phylloplane inhabitants is described. Several selective media were evaluated for selective enrichment of X. campestris pv. rnangiferaeindicae from mango plants. Boost broth supplemented with cycloheximide, methyl violet and methyl green enhanced growth of epiphytic X. campestris pv. mangiferaeindicae but not other phylloplane organisms. The identity of X. campestris pv. mangiferaeindicae selectively enriched from mango plant material was confirmed with monoclonal antibodies in an Enzyme-Linked Immunosorbent Assay. Preliminary field evaluations showed that selective enrichment and confirmation by ELISA could successfully detect latent infections of X. campestris pv. mangiferaeindicae in mango plants.
Bacterial black spot disease (BBS) of mango (Mangifera indica L.) caused by Xanthomonas campestris pv. mangiferaeindicae is spread by distribution of asymptomatic infected plants (MANICOM 1983). Diagnosis of pathogen free grafting material is an arduous task since the causal organism is a year round phylloplane resident (MANICOM 1986). Detection of the epiphytic phase of a pathogen is of primary importance to the industry in order to establish clean orchards as a preventative control strategy (MCGUIRE et al. 1986).
Rapid and accurate techniques available for detection of latent infections or epiphytic populations of phytopathogenic bacteria, include the enzyme-linked immunosorbent assay (ELISA) (SHERALD and LEI 1991), immunofluorescence (IF) (DUVELLIER and BRAGARD 1992) and dot-immunoassay (DIA) (COMSTOCK and IREY 1992). The ELISA has been used most successfully for detection of pathogens in seed (BENEDICT et al. 1989), plant tissue (SHERALD and LEI 1991) and potato tubers (COTHER and VRUGGINK 1980). Advantages of the ELISA include speed, versatility, quantitative precision and reproducibility, as well as potential for automation (CLARK et al. 1986).
Selective or semi-selective media are an invaluable aid for isolation of phytopathogenic bacteria from plants (STEAD 1992). Such media can also be used for selective enrichment of target organisms prior to implementation of other detection methods such as the ELISA. However, a minimum cell concentration of 1 O4 celldm1 is required for successful detection (MCLAUGHLIN et al. 1989). Selective enrichment of plant material may increase low concentrations of the pathogen to a detectable level. The ideal selective medium should be selective to at least the species level (CLAFLIN et al. 1987). Enrichment media have been described for X. campestris pv. campestris (CHANG et al. 1991), X. campestris pv. vesicatoria (SUAM et al, 199 l), X. campestris pv. phaseoli (MABAGALA and S A E ~E R 1992), X. campestris pv. dieffenbachiae (NORMAN and ALVAREZ 1989), X. campestris pv. juglandis (MULREAN and SCHROTH 1981) and X . campestris pv. translucens (SCHAAD and FORSTER 1985). As far as could be determined, no selective medium has been described for X. campestris pv. mangiferaeindicae.