Toxin Tolerance as a Marker for Resistance Breeding
Although the relevance of toxins in plant pathogenesis is still under discussion, purified toxins or fungal culture filtrates have been used to select cells and plants resistant to diseases, and toxin tolerance has been suggested as a promising marker for resistance in long range breeding programs. The aim of our work was to investigate the reliability of correlations between toxin tolerance and resistance in susceptible and resistant cultivars. The systems analyzed were Dianthus caryophyllus-Fusarium oxysporum f.sp. dianthi and Solanum tuberosum — Alternaria solani. Toxin tolerance was assayed using the two screening methods: plant cell and callus growth on media containing fungal culture filtrate, and ion leakage from callus cells or leaf cuttings challenged with culture filtrate (or fusaric acid).