2. USDA-ARS, SPA, CSRL, Plant Stress and Germplasm Development Research, 3810 4th Street, Lubbock, TX 79415 USA.
3. USDA-ARS, Crop Science Research Laboratory, Genetics and Precision Agriculture, 812 Highway 12E, Mississippi State, MS 39762, USA.
4. Institute of Genetics and Plant Experimental Biology, Academy of Sciences of Uzbekistan. Yuqori Yuz, Qibray region Tashkent district, 111226 Uzbekistan.
5. USDA-ARS, Genomics and Bioinformatics Research Unit, 141 Experiment Station Road, Stoneville, MS 38776, USA.
A collection of isolates of Fusarium oxysporum f. sp. vasinfectum (FOV) from cotton in Uzbekistan was characterized based on candidate gene sequencing approach. As a first step, cotton seedlings were artificially re-infected with randomly selected 8 unknown FOV isolates from the collection, FOV strains were re-isolated, and monospore cultures were obtained for genomic DNA preparation. Candidate genes such as elongation factor (EF-1α), beta-tubulin (BT), and ribosomal DNA (rDNA) were sequenced from the genomic DNAs of these unknown Uzbekistan FOV isolates and a set of 13 known races of FOV (races 1, 2, 3, 4, 6, 7, 8, and Australian VCG1112), collected from world research centers. A parsimony based phylogenetic analysis of known races of FOV together with unknown FOV isolates from the Uzbekistan collection clearly suggested that Uzbekistan FOV genotypes can be classified as race 1, 2 &6, race 3, and race 4 or 7. Based on EF-1α pair-wise genetic distances, no difference was observed between races 4 and 7 of FOV. Results from our research provided for the first time a comprehensive study on the identification of FOV races collected from different regions of Uzbekistan. In addition, this study will help breeders to develop resistance management strategies to combat the Fusarium wilt disease by breeding resistant cotton lines in Uzbekistan.
Keywords: FOV, cotton, wilting disease, Fusiarum, race identification