Experimental infection of Fusarium proliferatum in Oryza sativa plants; fumonisin B1 production and survival rate in grains

Fusarium proliferatum is a plant pathogenic fungus associated with crops such as asparagus and corn, and it possesses the ability to produce a range of mycotoxins, including fumonisins. In Asia, rice (Oryza sativa) is a staple cereal and is occasionally colonized by this fungus without obvious physiological changes. F. proliferatum is closely related to Gibberella fujikuroi (anamorph F. fujikuroi) responsible for Bakanae disease in rice; however there are few reports of F. proliferatum as a rice pathogen. In this study, we examined the pathogenic potential of F. proliferatum in rice plants with respect to browning, fumonisin production, and survival rates in rice grains. Fungal inoculation was conducted by spraying a conidial suspension of F. proliferatum onto rice plants during the flowering period. Browning was found on the stalk, leaf, and ear of rice. Fumonisin B1 was detected at levels from trace to 21 ng/g grains, using tandem mass spectrometry. Fungal recovery after 6 months indicated that F. proliferatum had high affinity to rice plants being still viable in grains. From this study, it can be concluded that F. proliferatum is a possible pathogen of rice and possesses a potential to produce fumonisin B1 in rice grains in the field.

► Rice plants inoculated with conidial suspension of Fusarium proliferatum exhibited browning on the ear.
► Fumonisin B1 accumulation was confirmed from trace to 21 ng/g in inoculated grains.
► Fusarium proliferatum was recovered from inoculated grains six months after maturation.
► High affinity of this fungus to rice grains was indicated.