Inhibition of Avicennia Marina antimicrobial protein against banana anthrax

In this paper,the leaves of Avicennia Marina were selected as materials. The different antimicrobial proteins were isolated by ammonium sulphate precipitation on different saturation ranges. The inhibition ratio of antimicrobial proteins against banana anthrax was evaluated by mycelial growth rate and spore germination.Storage experiments of postharvest banana fruits treated by the antimicrobial proteins were carried out separately.The results showed that,the three type of antimicrobial proteins separated by 35%,75%,85% ammonium sulfate precipitation( antimicrobial protein Ⅰ,Ⅱ,Ⅲ) showed obvious antifungal activity,which inhibited mycelial growth and the EC₅₀ value was 7.93 ± 0.29,16.21 ± 0.28,6.80 ± 0.13 μg / m L,respectively. The inhibition ratio of 100 μg / m L antimicrobial protein( Ⅰ,Ⅱ,Ⅲ) against spore germination was 95.5% ± 0.01%,97.5% ± 0.01% and 92.5% ± 0.01%respectively.By microexamination it was found that the three type of antimicrobial proteins could induce deformed growth of hyphae of banana anthrax,including twist of hyphae,necrosis of the hyphal wall and leakage of the cytoplasma.Application of the antimicrobial protein lead to a significant decrease in the incidence of banana anthrax during storage of postharvest banana fruits. The control efficiency of antimicrobial protein( Ⅰ,Ⅱ,Ⅲ) on banana anthracnose was 74.48% ± 0.68%,77.24% ± 0.53% and 75.87% ± 0.24%,respectively.