Fusarium oxysporum f. sp. vasinfectum (Fov) is a common soilborne fungal pathogen that causes Fusarium wilt (FW) disease in cotton. Although considerable progress has been made in cotton disease-resistance breeding against FW in China, and the R gene conferring resistance to Fov race 7 (FOV) in Upland cotton (Gossypium hirsutum) has been identified, knowledge regarding the evolution of fungal pathogenicity and virulence factors in Fov remains limited. In this study, we present a reference-scale genome assembly and annotation for FOV7, created through the integration of single-molecule real-time sequencing (PacBio) and high-throughput chromosome conformation capture (Hi-C) techniques. Comparative genomics analysis revealed the presence of six supernumerary scaffolds specific to FOV7. The genes or sequences within this region can potentially serve as reliable diagnostic markers for distinguishing Fov race 7. Furthermore, we conducted an analysis of the xylem sap proteome of FOV7-infected cotton plants, leading to the identification of 19 proteins that are secreted in xylem (FovSIX). Through a pathogenicity test involving knockout mutants, we demonstrated that FovSIX16 is crucial for the full virulence of FOV7. Overall, this study sheds light on the underlying mechanisms of Fov's pathogenicity and provides valuable insights into potential management strategies for controlling FW.
Keywords: Fov; Fusarium oxysporum f. sp. Vasinfectum race 7; Fusarium wilt; comparative genomics; cotton; secreted in xylem.