Fujikuroi

Fujikuroi typically refers to Fusarium fujikuroi, a filamentous fungus in the family Nectriaceae and a member of the Fusarium fujikuroi species complex (FFSC). This group comprises closely related fungi that are often studied together due to shared genetics and secondary metabolite potential. F. fujikuroi has historically been associated with rice pathology and research on gibberellin biosynthesis.

Ecology and distribution: F. fujikuroi inhabits soil, plant debris, and seed surfaces. It is a prominent agricultural pathogen in rice-producing regions, with a distribution linked to worldwide rice cultivation. The fungus can persist in crop residues and be translocated via infected seed or planting material.

Pathogenicity and disease: The species is best known for causing bakanae disease of rice, in which infected seedlings exhibit abnormal elongation and pale coloration due to the production of plant growth hormones called gibberellins by the fungus. Depending on environmental conditions and strain, infections can reduce vigor and yield, or, in severe cases, kill the plant. The pathogen can colonize vascular tissues and reach developing grains.

Metabolism and genetics: F. fujikuroi produces gibberellins, a key factor in its pathogenic effect on rice. The GA biosynthesis gene cluster has been studied extensively, and the FFSC genomes have been sequenced, providing insights into virulence, secondary metabolism, and host interactions. Some strains produce additional secondary metabolites, the presence and quantity of which vary by chemotype.

Management: Control measures focus on disease-free seed, seed health testing, and seed treatments; integrated practices such as crop rotation, residue management, and sanitation help reduce inoculum. Knowledge of the GA pathway informs research into disease resistance and potential biocontrol strategies.