Population biology of Fusarium oxysporum f. sp. vasinfectum (FOV), causal agent of fusarium wilt of cotton, in the southeastern United States

Fusarium oxysporum f. sp. vasinfectum (FOV), has recently caused devastating Fusarium wilt outbreaks in cotton fields in the southeastern United States. FOV is often classified into races or genotypes, based on polymorphisms at the translation elongation factor (EF-1a) locus. The goal of this research was to use population biology to understand i) the genetic diversity and population structure, and ii) the aggressiveness of FOV causing Fusarium wilt in southeastern cotton fields. Sequence analysis of the EF-1a locus and SNPs identified through genotyping-by-sequencing revealed that populations of FOV in the southeastern U.S. are genetically diverse, but not genetically structured by EF-1a race or genotype. A greenhouse inoculation experiment identified variation in isolates aggressiveness on cotton; these phenotypic differences were generally not associated with EF-1a sequence. These findings demonstrate that FOV is genetically and phenotypically diverse, and that EF-1a sequence polymorphisms are generally not biologically meaningful.