Inhibitory effect of sodium pheophorbide a on carrot gray mold

Sodium pheophorbide a (SPA) is a photoactivated antimicrobial active substance with great development prospects. In order to study its potential application in the control of carrot gray mold, the photoactivated antifungal effects of sodium pheophorbide a on Botrytis cinerea were determined by the mycelial growth rate method. Also, the effects of different mass concentrations of sodium pheophorbide a on the extension of carrot gray mold lesions and soluble protein content were determined. And the enzyme activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), phenylalanine ammonia lyase (PAL) in carrot tissues were also analyzed. Results showed that the mass concentration and light had significant effects on the antifungal activity of sodium pheophorbide a (P<0.05). And with the mass concentration of sodium pheophorbide a increased, its inhibitory effect gradually increased. The inhibitory rate of 20 mg/mL SPA solution on the mycelium growth was 89.19% under light conditions (4000 lx) and 72.20% under dark conditions. In addition, treatment with 20 mg/mL sodium pheophorbide a solution could effectively inhibit the spread of gray mold lesions on carrots. And within 84 h after inoculation, the lesion diameter was significantly smaller than that of other groups treated with different concentrations (P<0.05). Meanwhile, it can effectively maintain the stability of the protein content, and the activities of SOD, POD, CAT and PAL in carrot. In summary, sodium pheophorbide a could effectively inhibit the mycelial growth of B. cinerea and had a good control effect on carrot gray mold.