Screening for resistance to Diaporthe toxica in lupins by estimation of phomopsins and glucoseamine in individual plants

Authors

Manisha Shankar, University of Western AustraliaFollow
Wallace A. Cowling, University of Western Australia
Mark W. Sweetingham, Department of Agriculture, Western AustraliaFollow
K A. Than, Commonwealth Scientific and Industrial Research Organisation
J A. Edgar, Commonwealth Scientific and Industrial Research Organisation
A Michalewicz, Commonwealth Scientific and Industrial Research Organisation

Document Type

Article

Publication Date

6-1999

Journal Title

Plant Pathology

ISSN

Print: 0032-0862 Electronic: 1365-3059

Keywords

Diaporthe toxica, glucosamine, lupins, phomopsins, resistance, screening

Disciplines

Agronomy and Crop Sciences | Biosecurity | Plant Breeding and Genetics

Abstract

Immunological and biochemical assays were developed for screening for resistance to Diaporthe toxica in individual plants of narrow-leafed lupins (Lupinus angustifolius). The former was an enzyme-linked immunosorbent assay (ELISA) for measuring phomopsin mycotoxins and the latter gave an estimation of glucoseamine in infected stem pieces. Stems of L. angustifolius seedlings were inoculated with conidia from D. toxica cultures and, as expected with this latent disease, remained symptomless for 21 days after inoculation. At this time, phomopsins were measured in excised stems that had been incubated for 6 or 8 days to allow mycelial growth from latent infection structures, thereby increasing the phomopsins to detectable levels in individual plants. The estimation of glucoseamine was carried out on the same stems that had been assayed for phomopsins. The method was based on the alkaline deacetylation of chitin to chitosan, the glucoseamine residues of which are de-aminated with nitrous acid, yielding an aldehyde which is determined colorimetrically. At six days after excision, both tests clearly distinguished the very resistant, resistant, intermediate and susceptible lines and they may be useful in large-scale resistance screening in lupin breeding programmes. The ELISA of phomopsins is easier to use and would be particularly useful in the elimination of susceptible plants and those plants expressing intermediate levels of resistance during early generations of the breeding programme.

Recommended Citation

Shankar, M, Cowling, W A, Sweetingham, M W, Than, K A, Edgar, J A, and Michalewicz, A. (1999), Screening for resistance to Diaporthe toxica in lupins by estimation of phomopsins and glucoseamine in individual plants. Plant Pathology, 48 (3), 320-324.
https://library.dpird.wa.gov.au/bs_research/109