In vitro study of the growth, reproduction and pathogenicity responses of Fusarium oxysporum f. sp. zingiberi to autotoxins from ginger

ABSTRACT Long-term monoculture of ginger triggers Fusarium wilt, a disease caused by Fusarium oxysporum f. sp. niveum ( Foz ). However, the role of autotoxins in promoting pathogen growth remains unclear. Four representative autotoxins, syringic acid, coumarin, ferulic acid and 7-Hydrooxycoumarin were selected to investigate their allelopathic effects on the growth, reproduction, and virulence-associated traits of Foz . The responses of Foz to these compounds exhibited notable variations, which may be attributed to the structural differences among the autotoxins. The autotoxic compounds differentially enhanced the key pathogenic traits of Foz . Syringic acid was the most effective stimulant of mycelial growth and cell wall-degrading enzymes activity, concurrently boosting mycotoxin production via upregulating FUB3 gene expression. Ferulic acid was the most potent promoter of sporulation and biomass accumulation, whereas 7-Hydroxycoumarin most effectively stimulated conidial germination. Notably, coumarin suppressed mycelial growth but strongly induced mycotoxin synthesis in Foz . These results provide mechanistic insights into how autotoxins in ginger monoculture systems promote Fusarium wilt.