Download or read book Distribution of Fusarium Oxysporum F. Sp. Vasinfectum in the United States and Quantification of Race 4 in Soil written by Amanda Cianchetta and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A two-year survey was conducted to monitor the distribution of Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 and to assess the diversity of genotypes of FOV throughout the U.S. cotton belt. Partial sequences of the translation elongation factor (EF-1[alpha]) region of FOV cultured from symptomatic cotton plants were compared to a database of sequences of known genotypes of FOV. Five nominal races of FOV, races 1, 2, 3, 4, and 8, and four previously recognized southeastern genotypes, LA108, LA110, LA112 and LA127/140, were identified in the United States. All were pathogenic on cotton. A unique genotype of FOV, MDS-12, was identified in Alabama, Arkansas, Mississippi and Louisiana and was characterized with additional sequencing of the phosphate permease-like protein, [beta]-tubulin and intergenic spacer regions. FOV race 4 was not detected outside of California. Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 is an economically important disease of cotton in California. The fungus is seedborne and nearly impossible to eradicate from soil. In order to assess densities of soilborne inoculum, a quantitative PCR method using race 4 specific primers was developed. The protocol was evaluated using samples of sterile potting mix, cotton tissue and water spiked with known quantities of FOV race 4 DNA. Soil from cotton fields with known FOV race 4 infestation was also evaluated. The qPCR protocol succeeded in detecting FOV race 4 at concentrations as low as 102 conidia/ml, a level below the threshold of disease development in greenhouse studies; however it did not detect 10 fold differences in the target DNA template added to samples at levels of 102, 103 and 104 race 4 conidia/ml.