Abstract: In order to evaluate the antifungal stability of peptide Jelleine-I against Penicillium digitatum and the effect of lipopeptides derived from Jelleine-I (P1, P2, P3, P4, P5, P6) on controlling citrus postharvest green mold, the effects of temperature, pH, cation and protease on the antifungal activity of Jelleine-I and the disease control effect of Jelleine-I lipolypeptides in vitro and in vivo was tested. The results showed that the antifungal activity of Jelleine-I against P. digitatum was thermostable and insensitive to pH, and remained stable at temperatures of 40–80 ℃ and pH 3–10. Different cations had different effects on the antibacterial activity of Jelleine-I, which was maintained after being treated with Na+ (expect for high concentration of 200 mmol/L) and K+, but decreased after being treated with Ca2+. The antifungal activity of Jelleine-I was maintained in the presence of one of three proteases at low concentration, but decreased gradually with increasing protease concentration. The lipopeptides formed by linking one of six different natural bacteriostatic substances to Jelleine-I were able to effectively control citrus postharvest green mold. The effect of lipopeptides P1 and P2 showed no significant difference from that of Jelleine-I, which was stronger than that of four other lipopeptides, possibly due to their excessive hydrophobicity. These results showed that the antifungal activity of Jelleine-I against P. digitatum was thermostable, resistant to acid and base, and insensitive to K+, Na+ and low concentrations of protease. In conclusion, Jelleine-I and lipopeptides P1 and P2 hold great promise for application in the field of citrus postharvest preservation.

Key words: Jelleine-I, antifungal stability, lipopeptides, green mold, control effect