Screening for Alternaria brassicicola resistance in the Brassicaceae: Bio-assay optimization and confocal microscopy insights into the infection process

Department of Genetics, Breeding, and Biotechnology of Vegetable Crops, Research Institute of Horticulture, Skierniewice, łódzkie, Poland
Laboratory of Confocal and Fluorescence Microscopy, Institute of Biochemistry and Biophysics - Polish Academy of Sciences, Warszawa, mazowieckie, Poland
School of Informatics, State Higher Vocational School in Skierniewice, Skierniewice, łódzkie, Poland
DOI
10.7287/peerj.preprints.1360v1
Subject Areas
Agricultural Science, Cell Biology, Microbiology, Plant Science
Keywords
dark leaf spot, Alternaria blight, cabbages, resistance testing, controlled conditions, field assays, histochemical dual stain, actin staining
Copyright
© 2015 Nowakowska et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Nowakowska M, Wrzesińska M, Kamiński P, Nowicki M, Lichocka M, Tartanus M, Kozik EU. 2015. Screening for Alternaria brassicicola resistance in the Brassicaceae: Bio-assay optimization and confocal microscopy insights into the infection process. PeerJ PrePrints 3:e1360v1

Abstract

Heavy losses incited yearly by Alternaria brassicicola on the vegetable Brassicaceae – have prompted our search for sources of genetic resistance against the resultant disease, dark leaf spot. We optimized several parameters to test the performance of the plants under controlled conditions to this disease, including leaf age and position, inoculum concentration, and incubation temperature. Using these optimized conditions, we screened a collection of 38 Brassicaceae cultigens with two methods (detached leaf and seedlings). Our results show, that either method can be used for the A. brassicicola resistance breeding, while the plant’s genotype was crucial in determining its response to the pathogen. The bio-assays for Alternaria resistance were more effective than the field tests, and resulted in identification of two interspecific hybrids that might be used in breeding programs. Confocal microscopy analyses of the leaf samples provided novel insights into the pathogen mode of infection: Direct epidermal infection or stomatal attack were dependent on plants’ resistance against A. brassicicola. Further, the actin network of the host cells reorganized around the papillas deposited under the pathogen’s appressorium. Papilla composition is predicted to be important in determining the plant’s resistance.

Author Comment

This is a submission to PeerJ for review.