Characterization of Ascochyta as pathological species of pea (Pisum sativum L.) at the North-West of Algeria

It is the weakness of works on this pathogenic agent that pushed us to characterize Ascochyta on the plans morphological and molecular. Thirty seven samples of biological materials were isolated from three zones i.e., Mostaganem, Relizane and Mascara all located at North-West of Algeria. The samples are the isolated strains and are obtained from various organs of pea seedlings attacked by Ascochyta sp. According to the morphological aspect, the results allowed to distinguish between three categories of strains representing the three species. Nevertheless, the distinction between these three categories is not very reliable for cause of the extreme variability of these species according to their middle of culture. According to the molecular data, all the isolated-strains who's Internal Transcript Space (ITS) regions in DNA have been amplified by Polymerase Chain Reaction (PCR) have expressed identical results with the same size of the PCR products (550 Pb). No polymorphism is noted at the set of the tested strains. On the other hand, the molecular sequencing permitted to distinguish Ascochyta pisi from Ascochyta pinodes and Ascochyta pinodella. These last two species remain similar in their ITS1 and ITS4 regions and don't show any difference. This study was done at the North-West of Algeria between 2004 and 2008. The prospection of other DNA regions with other molecular markers is to be planned in order to detect polymorphism between Ascochyta pinodes and Ascochyta pinodella. © 2009 Asian Network for Scientific Information.