Charakterisierung von Resistenzgenen gegen Verticillium longisporum in Brassicaceen
Biochemistry
Plant Breeding and Plant Pathology
Final Report Abstract
Plants infected by Verticillium longisporum show a complex pattern of disease symptoms and developmental reactions, incl. premature seed ripening, chlorosis or stunting. Our study aimed at the identification of host genes controlling different disease parameters (AUDPC, stunting, fungal colonization) and the implications of genes controlling host development in the disease. We identified host accessions in Arabidopsis and Brassica alboglabra that differed strikingly in their susceptibility to V. longisporum and used these as parents for mapping experiments. Like in other crops systemic colonization of the shoot depended on the onset of flowering in both host species. Therefore, all experiments were executed under long day regime and plants were assessed for shoot colonization and other disease parameters at the onset of seed maturation. In B. alboglabra we identified 2 major QTL that explained significant proportions of the variation for the degree of fungal colonisation and AUDPC in F3 families. QTL for the control of different stunting parameters (stem length, fresh weight) showed some overlap with QTL for AUDPC or colonisation. Two major QTL controlling differences in developmental velocity were identified that did not show interdependence to disease resistance. As for B. alboglabra, fungal shoot colonization rates were the most reliable resistance parameter in repeated experiments with Arabidopsis. Resistance to Verticillium-induced stunting was inherited more independent from resistance to shoot colonisation than in B. alboglabra. QTL for colonisation resistance did show some overlap with QTL that controlled development or with the morphological marker Erecta. Fine-mapping of different disease parameters in the Erecta region in near-isogenic lines revealed a close linkage of loci controlling either stunting or colonisation resistance. QTL and candidate genes from Arabidopsis will be used to identify homologs/ orthologs in B. alboglabra and to check for co-localization with QTL that were identified in this species. Cloning of genes conferring either colonisation resistance or stunting resistance from Arabidopsis will allow the functional analysis of both types of resistance. Development interrelations with the disease phenotype were complex and should be considered for experimental designs.
Publications
- (2009): Genetics of resistance against the vascular pathogen Verticillium longisporum in Brassica and Arabidopsis thaliana. In: Feldmann, F., Alford, D. V., Furk, C. (eds.): Crop plant resistance to biotic and abiotic factors: Current potential and future demands. Proceedings of the 3rd international symposium of plant protection and plant health in Europe, Berlin, Germany
Häffner, E., Konietzki, S., Socquet-Juglard, D., Gerowitt, B. & Diederichsen, E.
- (2010) Genetic and environmental control the Verticillium syndrome in Arabidopsis thaliana. BMC Plant Biol 10: 235
Häffner E, Karlovsky P, Diederichsen E
(See online at https://doi.org/10.1186/1471-2229-10-235)
