A competitive ELISA for detecting resistance to latent stem infection by Diaporthe toxica in narrow-leafed lupins

Authors

Manisha Shankar, University of Western AustraliaFollow
Andrew Reginald Gregory, Department of Agriculture, Western Australia
M J. Kalkhoven, Department of Agriculture, Western Australia
W. Cowling, University of Western Australia
Mark W. Sweetingham, Department of Agriculture, Western AustraliaFollow

Document Type

Article

Publication Date

12-1998

Journal Title

Australasian Plant Pathology

ISSN

Print: 0815-3191 Electronic: 1448-6032

Keywords

Diaporthe toxica, competitive ELISA, Lupinus angustifolius, resistance

Disciplines

Agronomy and Crop Sciences | Biosecurity | Plant Breeding and Genetics

Abstract

Resistance to Diaporthe toxica in 12 lines of narrow-leafed lupin (Lupinus angustifolius) was assessed by a competitive enzyme-linked immunosorbent assay (ELISA). Seedlings were inoculated with the pathogen and after 21 days resistance was assessed by counting latent infection structures in epidermal tissue under the microscope. Infected stem pieces were then incubated for 6 days in moist chambers before treatment with antisera to D. toxica. There was a high correlation between the ELISA reaction and the frequency of latent infection structures on the 12 lines (r = 0.92, P < 0.001). Visual confirmation of the ELISA result was obtained by further incubating the excised stems for up to 12 days and assessing the degree of fungal development. There was a high correlation between the ELISA result after 6 days incubation and visual ratings of fungal development after 12 days incubation (r = 0.89, P < 0.001). The ELISA test distinguished susceptible, resistant and very resistant lines, but failed to distinguish the intermediate line from resistant lines. A similar result was obtained with visual observation of fungal development on excised stems, with the exception that the intermediate line was not distinguishable from susceptible lines. The most accurate assessment of resistance was by microscope observation of latent infection structures, which allowed quantitative assessment of resistance and consistently separated susceptible, intermediate, resistant and highly resistant lines.

Recommended Citation

Shankal, M., Gregory, A., Kalkhoven, M.J. et al. A competitive ELISA for detecting resistance to latent stem infection by Diaporthe toxica in narrow-leafed lupins. Australasian Plant Pathology 27, 251–258 (1998). https://doi.org/10.1071/AP98028