Rezaei, R. (2015) Identification of small- spored Alternaria species based on morphological characteristics and rpb2 gene sequencing in Sistan fields. Masters thesis, University of Zabol.
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Abstract
Alternaria (Hyphomycetous), is one of the genus large and complex in terms of morphology. Several species of the genus Alternaria have been identified on agricultural production, which often causing leaf spot and fruit rot before and after harvest. In this study, for identification of Alternaria small-spores species in Sistan region, for the first time, Alternaria species from various host plants were isolated and studied according to morphological and molecular characteristics. A total, more than 250 fungal isolates showing Alternaria characteristics were isolated from different hosts. Morphological studies of the isolates were performed on PCA cultural under standard conditions (8 hr light, 16 hr dark and temperature 20-25˚C). Nine species Alternaria alternate, A. solani, A. arborescens, A. triticina, A. tenuissima, A. dumosa, A. porii, A. destruens and A. mimicula of this genus were identified. A. alternata was found the most common species. To molecular studies were extracted DNA number of isolates and rpb2 gene region amplified using Polymerase Chain Reaction (PCR) and PCR products were purified and sequenced. Blast analyses showed that there was significant variation in rpb2 gene sequence among different isolates. According to morphological characteristics and nucleotide sequence data, this is the first report of A. alternata on Medicago sativa, Raphanus sativus, Verbascum thapsus and Sansvieria trifasciata; A. arborescens on Plantago lanceolata L. and A. tenuissima on Aglaonema commutatum, Calendula persica, Petroselinum sativum Hoffm ٬Malva neglecta Wallr and Cardaria draba in Iran which verified by morphology and molecular data. In between, A. arborescens on Plantago lanceolata L. and A. tenuissima on Aglaonema commutatum and Cardaria draba for the first time in the world were isolated from the hosts. Based on analysis DNA sequensces of rpb2 gene region and phylogenetic tree drawn, the isolates were grouped in two clades and 14 sub- clade. A. alternata and A. tenuissima isolates were grouped in two sub-clades. Isolates from Mangifera indica and Mentha aquatica showed maximum similarity with A. tenuissima and A. destruens based on morphological characteristics respectively, but according to rpb2 gene sequence, isolate of Mangifera indica was placed in separate clade far from other isolates and isolate of Mentha aquatica was grouped near isolates with similar sequence with A. alternata. According to the results, rpb2 gene sequence is useful for separation small- spored species.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Alternaria, Taxonomy, rpb2 gene, Morphological characteristics |
| Subjects: | Q Science > QK Botany |
| Depositing User: | admin admin1 admin2 |
| Date Deposited: | 30 Oct 2016 07:11 |
| Last Modified: | 30 Oct 2016 07:11 |
| URI: | http://eprints.uoz.ac.ir/id/eprint/929 |
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