Screening of antagonist bacteria with antifungal activity against postharvest diseases on lemon (Citrus limon (L.) Burm.f.)

Abstract: This study was carried out in vitro conditions to determine the bacteria

biological control agents of against different fungal agents causing postharvest

losses in lemon fruit. For this purpose, isolations were made from diseased lemon

fruits, as a result of isolations three different fungal species were isolated,

pathogenicity tests were carried out and according to the results of molecular

diagnosis, these isolates were found to be Alternaria alternata (ET 119),

Colletotrichum gleosporoides (ET 120) and Penicillium chrysogenum (ET 121).

Percent inhibition rate of thirty-six antagonist bacterial isolates belonging to eight

different genera against pathogenic fungus isolates was determined by dual

culture test according to a randomized plot experiment design with 3 replications.

According to the results obtained, the highest effect against the three pathogen

isolates was detected in TV 53D (67.46%: Brevibacillus choshinensis), this isolate

was followed by TV 16F (66.27%: Bacillus subtilis) and FDG 37 (62.30%:

Pseudomonas fluorescens) isolates, respectively. More detailed studies should be

carried out in the future under controlled conditions with the most effective

antagonist bacterial isolates.

Keywords: Antifungal activity, Bacillus subtilis, antagonist bacteria, biological

control, Pseudomonas fluorescens