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The study was conducted in the laboratories of National Commission for Biotechnology and Damascus university -faculty of Agriculture with the aim of highlighting the sorghum crop, identifying local smut pathogens and providing a molecular test for detection of smut infection at the seedling stage. The Teliospores of smut fungal pathogens were collected from infected plants of different species of Sorghum sp. during the summer of 2015. They were classified using a taxon key based on the morphological characteristics of smut teliospores, sori, host plant, and the infection symptoms. the susceptibility of several sorghum genotypes to seedborne fungal infection with S. sorghi, S. cruentum, and S. reilianum, was tested during three growing seasons 2016-2017-2018. plants of broom corn and Razineah 17 cultivar were infected only by covered smut, while all genotypes of sweet sorghum did not show any symptoms of covered smut, head smut or loose smut. It was also found that the Razineah 17 is the most susceptible to covered smut infection. Twelve ISSR primers were used in the screening of any species- specific bands based on seven teliospores isolated DNA from different smut species, that its sequence can be used to design special primers for detection of that specific DNA fragment in the infected plant. The total number of amplified fragments was 99, with a polymorphism rate of 95.25%. The phylogenetic tree showed that isolates from the same species grouped together although that they were from different Sorghum species, results of ISSR amplification products did not show any species-specific band so no specific primers can be designed for detection of infected plants. In the other hand, discrimination of infected plant with Covered smut, loose smut, and head smut was possible using primer pair G3pD1096F/ G3pD2020R in PCR reaction with DNA extracted from the apical meristem of infected and healthy plants of sorghum (Razineah 17) and johnsongrass. Results of assessment of the inhibitory effect of several concentrations of lavender, mint, and Oregano essential oil, also 80% acid whey, and the fungicide Benzimidazole on the germination of covered smut teliospores (MS isolate), showed that concentration of (2 µl/ml -3.125 µl/ml) from Oregano essential oils and essential oils of lavender at a concentration of (6.25 µl/ml), and 80% acid whey has the best rate of inhibition of spore germination without significant differences between them, which were estimated respectively (95.27% - 94.12% - 94.02% - 93.62%). Phytotoxicity experiments were carried out before that and the results showed that the highest concentration which didn’t have a negative effect on Sorghum seed germination was 6.25µl/ml for both peppermint and lavender oil, while it was 3.125µl/ml for Oregano oil. Also, treatment with 80% acid whey did not affect the germination rate significantly.
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Keywords: Sorghum, Smut, Sporisorium Spp., Early Detection, Cultivars Susceptibility, Inhibition of Teliospores Germination.
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