The present study aimed to evaluate the antagonistic potential of Aspergillus spp. against Macrophomina phaseolina. All the tested species namely Aspergillus niger, Aspergillus terreus, Aspergillus flavipes, Aspergillus flavus and Aspergillus sydowii were identified by rDNA sequencing of ITS and β-tubulin regions prior to determine their antagonistic behaviour against the pathogen by using dual culture technique. A. flavipes proved to be the most effective in reducing the colony diameter of M. phaseolina (53%) followed by A. niger (41%) and A. flavus (37%) over control, whereas A. sydowii and A. terreus were the least effective with 6.2% and 5% in vitro biocontrol potentials, respectively. The secondary metabolites produced by A. flavipes were tested against the genomic DNA of M. phaseolina to understand the mechanism of antagonism. The bioactive metabolites completely degraded the pathogenic fungal DNA at higher concentrations of 400% and 500% after 24 h. Moreover, the chloroform and ethyl acetate fractions of culture filtrates of A. flavipes were subjected to GC–MS analysis for the identification of potential antimicrobial compounds and a total of 14 and 8 compounds were identified in these fractions, respectively. Among these 9,12-octadecadienoic acid (Z,Z)- followed by 1,2-benzedicarboxylic acid, diisooctyl ester; decane; hexadecanoic acid,2-hydroxy-1-(hydroxymethyl) ethyl ester; benzene, 1,2,3-trimethyl; n-hexadecanoic acid and naphthalene were the predominant compounds with peak areas of 31.72%, 26.27%, 18.47%, 10.62%, 6.82%, 6.04% and 5.67%, respectively. Literature shows that some of identified compounds possess antimicrobial properties, which might be responsible for control of M. phaseolina.

本研究旨在评估曲霉属的拮抗潜力。对抗Macrophomina phaseolina。所有参与测试的种类，即黑曲霉，土曲霉，黄柄曲霉，黄曲霉和聚多曲霉是通过使用双重培养技术，以确定他们对病原体拮抗行为之前ITS和β微管蛋白的区域rDNA序列分析鉴定。A. flavipes被证明是最有效地减少M. phaseolina (53%)的菌落直径，其次是A. niger (41%) 和A. flavus(37%) 超过控制，而A. sydowii和A. terreus的效果最差，分别为 6.2% 和 5% 的体外生物防治潜力。A. flavipes产生的次生代谢物针对M. phaseolina的基因组 DNA 进行了测试，以了解拮抗作用的机制。生物活性代谢物在 24 小时后以 400% 和 500% 的更高浓度完全降解致病真菌 DNA。此外，黄曲霉培养物滤液的氯仿和乙酸乙酯部分进行 GC-MS 分析以鉴定潜在的抗菌化合物，并且在这些馏分中分别鉴定了 14 种和 8 种化合物。其中 9,12-十八碳二烯酸 (Z,Z)- 之后是 1,2- 苯二甲酸，二异辛酯；癸烷；十六烷酸，2-羟基-1-(羟甲基)乙酯；苯，1,2,3-三甲基；正十六烷酸和萘是主要化合物，峰面积分别为 31.72%、26.27%、18.47%、10.62%、6.82%、6.04% 和 5.67%。文献表明，一些已鉴定的化合物具有抗菌特性，这可能是控制菜豆的原因。