Fusarium Wilt of Cotton Pathogen Population Characterization, Virulence, & Resistance Mechanism Determination, & Marker Assisted Resistance Breeding

1) Characterize genetic variation, virulence, and nematode interactions of F. oxysporum isolates from the Mid-South. 2) Introgress resistance to FOV race 4 (FOV4) from ?Pima S-2?, ?Pima S-4?, ?Pima S-6?, ?Sakel?, ?Seabrook Sea island 12B-2?, and Gossypium arboreum Acc. No. 190 into BAR 32 lines that are homozygous for Ren2,3 and Mi1,2 and are highly resistant to both root-knot and reniform nematodes. Identify markers associated with resistance. 3) Identify FOV4 virulence genes affected by transposon ?Tfo1? and other mutator-like elements, and confirm the virulence role of the identified gene by gene knock-outs subsequent pathogenicity assays with knock-outs. 4) Determine the importance of fusaric acid in virulence and competition with antagonists using pathogenicity assays of various knock-out mutants in root rot pathotype isolates of Fov race 4 and Australian biotype.