New Genotypes of Fusarium oxysporum f. sp. vasinfectum from the Southeastern United States

Abstract

Sixty-one isolates of Fusarium oxysporum f. sp. vasinfectum were collected from cotton plants (Gossypium spp.) with symptoms of Fusarium wilt to determine the composition of races present in the southeastern United States. Analysis of partial sequences of the translation elongation factor gene revealed four novel genotypes, as well as the presence of races 3 and 8 for the first time in the United States outside of California. The majority of isolates (16 of 27) sampled from Arkansas were novel genotypes. A subset of isolates representing the novel genotypes was compared with previously described races using sequences from translation elongation factor, phosphate permase, and β-tubulin genes and their pathogenicity on a total of six Upland (Gossypium hirsutum) and Pima (G. barbadense) cotton cultivars. Two of the novel genotypes belonged to a clade containing races 1, 2, 4, 6, and 8 and two shared ancestry with race 3. All new genotypes were pathogenic to at least some of the cotton cultivars tested. The Pima cv. Phytogen 800 was relatively resistant to all genotypes of the pathogen. These results indicate that the population of F. oxysporum f. sp. vasinfectum in the southeastern United States is more diverse than previously recognized.

Registration of glandless ‘NuMex COT 17 GLS’ upland cotton cultivar with Fusarium wilt race 4 resistance

“…There are currently eight races recognized worldwide, including races 1, 2, 3, 4, and 8 in the United States (Holmes, Bennett, Spurgeon, Colyer, & Davis, ; Kim, Hutmacher, & Davis, ); race 3 in Egypt and Israel; race 4 in India; race 5 in Sudan; race 6 in Brazil; and races 7 and 8 in China (Sanogo & Zhang, ). In the last 15 yr, the yield loss in California caused by FOV race 4 (FOV4) has increased (Hutmacher et al., ) since it was first reported in the state in 2001 (Holmes et al., ; Kim et al., ). This race has been spread eastward to other western and southwestern cotton states, including far‐western Texas (El Paso County), based on field scouting followed by molecular confirmation (Halpern et al., ).…”

Elite Upland Cotton Germplasm‐Pool Assessment of Fusarium Wilt Resistance in California

“…Recently, analyses with partial sequences from the above genes of 61 FOV isolates across the United States (Holmes et al, 2009) revealed four additional FOV genotypes, and for the first time, Races 3 and 8 were reported outside of California. The majority of these novel genotypes were from the state of Arkansas and were pathogenic to at least one cotton cultivar used in the study (Holmes et al, 2009).…”

Registration of upland cotton cultivar ‘Acala 1517‐20’ resistant to Fusarium wilt race 4

“…In the United States, races 1, 2, 3, 4, and 8 were identified (Cianchetta et al., ; Holmes, Bennett, Spurgeon, Colyer, & Davis, ; Kim, Hutmacher, & Davis, ). Race 4 (FOV4) was originally identified in India and has become a major threat to US cotton production (Halpern et al., ; Hutmacher et al., ; Zhu et al., ) since it was first reported in California in 2001 (Holmes et al., ; Kim et al., ). Other races are recognized in other cotton‐producing countries, including race 3 in Egypt and Israel, race 5 in Sudan, race 6 in Brazil, and races 7 and 8 in China (Hillocks, ; Sanogo & Zhang, ).…”

“…Fusarium wilt is one of the diseases most destructive to the development of cotton. In the United States, races 1, 2, 3, 4, and 8 were identified (Cianchetta et al, 2015;Holmes, Bennett, Spurgeon, Colyer, & Davis, 2009;Kim, Hutmacher, & Davis, 2005). Race 4 (FOV4) was originally identified in India and cultivars.…”