THI4 — Fusarium oxysporum f. sp. lycopersici 4287

Summary

FoTHI4 (FOXG_02153) on chromosome 5 of Fusarium oxysporum f. sp. lycopersici 4287 encodes a protein with thiamin-phosphate diphosphorylase and hydroxyethylthiazole kinase activities. The protein contains thiamine phosphate synthase and ribokinase-like domains and localises to the cytoplasm and cytosol. The gene is associated with thiamine diphosphate biosynthesis, thiamine anabolism, and RNA splicing. Loss of FoTHI4 activity is linked to inviability, increased heat sensitivity, decreased competitive fitness, and reduced chemical resistance, alongside abnormal chromosome maintenance and increased autophagy. The gene is also associated with oxidative stress response. Studies of related genes in other species link the THI4 family to decreased vegetative growth, desiccation sensitivity, and altered nitrogen utilisation, though these associations are not yet established in F. oxysporum f. sp. lycopersici.