|Authors: ||N. Bessadat, B. Hamon, N. Bataillé-Simoneau, K. Mabrouk, P. Simoneau|
|Keywords: ||Alternaria blight, leaf spot, Solanaceae, etiology, pathogen, taxonomy, virulence|
Leaf blight and spots are among the most destructive diseases in crops of the Solanaceae family in the Mediterranean area.
In Algeria, Alternaria spp., the causal agents of these diseases have been regularly isolated from Solanum lycopersicum and Solanum tuberosum, but also from several other cultivated and wild solanaceous plants that have recently gained importance as potential new hosts.
Samples with suspected symptoms of Alternaria infection were collected from fields inspected during the growing seasons of 2011-2017. Morphological characteristics analyses indicate that the fungus Alternaria was frequently isolated (56.2%) from symptomatic tissues and populations from this fungal genus were represented by large-spored isolates being prevalent on potato and small-spored species that were prevalent on other cultivated and weed species.
Phylogenetic analyses based on glyceraldehyde-3-phosphate dehydrogenase (GPD) and the second largest subunit of RNA polymerase II (RPB2), separated Alternaria isolates into three groups referable to sections Alternaria, Ulocladioides and Porri. The isolates were identified as belonging to eight different species, i.e. A. solani, A. linariae, A. grandis, A protenta in the section Porri, A. alternata, A. arborescens in the section Alternaria, and A. consortialis, A. cantlous in the section Ulocladioides. Micro- and macroscopic characteristics confirmed this separation of Alternaria isolates into three sections.
Results obtained from the pathogenicity tests showed that large-spored isolates from identified species were all able to produce symptoms on both tomato and potato leaves.
Download Adobe Acrobat Reader (free software to read PDF files)