Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Genotyping of Fusarium Graminearum And Fusarium Culmorum Isolates By Rapd Markers

Totally 18 Fusarium isolates, causing head blight on barley and wheat which were planted in various regions of our country, were genetically identified by using PCR-based methods, in this study. Moreover, genotyping of these isolates were carried out by RAPD markers.

First of all, 28S rRNA gene that is highly conserved in all fungi was scanned in Fusarium isolates by PCR. It was shown that each of isolates had this conserved region. Isolates were diagnosed at species level by amplifying SCAR markers. Also, it was confirmed that five of isolates (F5, F6, F7, F8, F9), obtained from culture collection, belonged to F. graminearum. However, F13 from F. culmorum isolates could not be diagnosed by SCAR markers. It was shown that the remaining 11 isolates belonged to this species. It was also determined that field isolate didn’t belong to none of these species. Additionally, based on sequences of tri7 and tri3 genes, involved in the mycotoxin biosynthetic pathway, PCR assays were used to detect chemotype and sub chemotypes. It was determined that all Fusarium isolates used in this study had DON chemotype. Also, it was shown that F. graminearum isolates had a potential to produce 15-ADON, all F. culmorum isolates except F13 to produce 3-ADON. But sub chemotype of field isolate (B) could not be determined. Identification of containing full length tri7 gene in F. culmorum isolates studied in this study, different from
F. culmorum isolates at 3-ADON sub chemotype determined until now, is a remarkable finding.

The intraspecific and interspecific genetic similarity of totally 18 isolates, isolated from different areas of our country, was investigated by using RAPD method. Intraspecific similarity of F. graminearum was calculated as 43-76.1 % (respectively, F5 and F8, F6 and F7), of F. culmorum as 49-81.1 % (respectively, F2 and F17, F20 and F21). Genetically closest isolates between these two species were F. graminearum F7 and F. culmorum F2 (13.7 %). Moreover, it was observed that two species had high polymorphism potantial (93.3 %).

Usability of reproducible stable polymorphic RAPD markers as SCAR markers was researched. It was determined that seven of 22 RAPD markers which were scanned for this purpose had high homology with different organisms’ genomes. However, it was indicated that these RAPD markers can not be used as SCAR markers in Fusarium species diagnosis since obtained RAPD markers were not belonged to allelic region