The biocontrol potential of antagonistic bacteria and yeasts isolated from tomato phyllosphere and fructoplane was evaluated against fruit rot of tomato caused by Alternaria alternata. A total of 48 bacterial and 24 yeast isolates were obtained from field-grown tomato leaves/fruits collected from Barka, Oman. The antagonistic activities of these isolates were evaluated against A. alternata using in vitro dual culture assay. Among the 72 bacterial and yeast isolates tested, one yeast (Meyerozyma guilliermondii) and two bacteria (Enterobacter roggenkampii and Pseudomonas aeruginosa) showed inhibitory activity against A. alternata. Examination of hyphal morphology of A. alternata at the edge of inhibition zone using scanning electron microscopy revealed abnormalities such as twisting, shriveling, distortion and collapsing of hyphae. Postharvest treatment of tomato fruits with E. roggenkampii, P. aeruginosa and M. guilliermondii reduced the fruit rot lesion size by 60%, 57% and 50%, respectively, compared to untreated control. The antifungal metabolites produced by the antagonistic yeast M. guilliermondii were fractionated using thin-layer chromatography. Characterization of the bioactive fractions using gas chromatography-mass spectrometry revealed the presence of different types of alkanes, predominantly tricosane and pentacosane, suggesting that volatile compounds, especially alkanes, produced by M. guilliermondii might also be involved in the suppression of A. alternata.

评估了从番茄叶球和果糖平面分离的拮抗细菌和酵母的生防潜力对链格孢菌引起的番茄果实腐烂的影响。从从阿曼巴卡（Barka）收集的田间种植的番茄叶/果实中获得了总共48种细菌和24种酵母分离株。使用体外双重培养测定法评价了这些分离物对交链孢霉的拮抗活性。在测试的72种细菌和酵母分离物中，一种酵母（Meyerozyma guilliermondii）和两种细菌（罗氏肠杆菌（Enterobacter roggenkampii）和铜绿假单胞菌（Pseudomonas aeruginosa））表现出对交链杆菌的抑制活性。。使用扫描电子显微镜检查抑制区边缘的交链孢菌的菌丝形态，发现了菌丝的扭曲，收缩，变形和塌陷等异常情况。与未处理的对照相比，番茄果实的收获后处理用罗氏大肠杆菌，铜绿假单胞菌和古吉尔蒙德氏菌分别将果实腐烂病斑的大小减小了60％，57％和50％。拮抗酵母菌guilliermondii产生的抗真菌代谢物用薄层色谱分离。使用气相色谱-质谱分析法的生物活性组分的表征揭示不同类型的链烷烃的存在，主要是二十三烷和二十五烷，这表明挥发性化合物，特别是烷烃，所生产M.季也蒙也可能在的抑制参与链格孢。