INFLUENCE OF LIGHT ON GROWTH, CONIDIATION AND FUMONISIN PRODUCTION BY FUSARIUM VERTICILLIOIDES

Light is a very important signal for fungi since it influences many different physiological responses. We analyzed the influence of light of varying wavelength and intensity on the growth, conidiation and fumonisin B1 (FB1), B2 (FB2) and B3 (FB3) biosynthesis by Fusarium verticillioides ITEM 10027. Wavelengths from both sides of the spectrum, from red (627 nm) to blue (470-455 nm), had a stimulating effect on the growth and fumonisin production, with an increase of up to 150% of total fumonisins analyzed, compared with dark incubation. If the intensity of the 455 nm blue light was increased, fumonisin biosynthesis was reduced. Furthermore the incubation under a short wave blue light (390 nm) had an inhibitory effect on the fungal growth and the fumonisin production was reduced by 85%. White pulsing light had an inhibitory effect on fumonisin production, with a reduction of about 50%, but not on the fungal growth, comparable with the dark incubation. The regulation of fumonisin production was analyzed by real time RT-PCR, measuring the expression level of fum1, fum21 and fvVE1 transcripts, that encode protein involved in fumonisin biosynthesis, revealing a correlation between gene expression and fumonisin production.