Agroecology Program, Earth and Environment Department, Florida International University, Miami, FL 33199, United States.
Chemistry and Biochemistry Department, Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, United States.
Lett Appl Microbiol. 2024 Mar 1;77(3). doi: 10.1093/lambio/ovae025.
Endophytic microorganisms associated with medicinal plants are of particular interest as they are a potential source of new bioactive chemicals effective against novel emerging and drug-resistant pathogens. Agave americana is a tropical medicinal plant with antibacterial, antifungal, and anticancer properties. We studied the biodiversity of fungal endophytes of A. americana and their antimicrobial production potential. Isolated endophytic fungi were classified into 32 morphotypes (15 from stem and 17 from leaf) based on their cultural and morphological characteristics. Among the fungal crude extracts tested, 82% of isolates from the leaves and 80% of the isolates from the stem showed antibacterial activity against the bacterial strains (Escherichia coli ATTC 25902, Staphylococcus aureus ATTC 14775, and Bacillus subtilis NRRL 5109) tested. Extracts from four fungal isolates from leaves showed antifungal activity against at least one of the fungal strains (Candida albicans ATTC 10231 and Aspergillus fumigatus NRRL 5109) tested. Crude extracts of seven fungal isolates showed a zone of inhibition of more than 11 mm at 10 mgml-1 against both Gram-positive and Gram-negative bacteria tested. Penicillium, Colletotrichum, Curvularia, Pleosporales, Dothideomycetes, and Pleurotus are the main endophytes responsible for bioactive potential. These results indicate that A. americana harbors endophytes capable of producing antimicrobial metabolites.
与药用植物相关的内生微生物特别有趣，因为它们是对抗新型新兴和耐药病原体的新生物活性化合物的潜在来源。龙舌兰是一种具有抗菌、抗真菌和抗癌特性的热带药用植物。我们研究了龙舌兰内生真菌的生物多样性及其抗菌产物的产生潜力。根据其培养和形态特征，将分离出的内生真菌分为 32 个形态型（15 个来自茎，17 个来自叶）。在所测试的真菌粗提取物中，叶片分离出的 82%的菌株和茎分离出的 80%的菌株对测试的细菌菌株（大肠杆菌 ATTC 25902、金黄色葡萄球菌 ATTC 14775 和枯草芽孢杆菌 NRRL 5109）表现出抗菌活性。来自叶片的四个真菌分离物的提取物对至少一种测试的真菌菌株（白色念珠菌 ATTC 10231 和烟曲霉 NRRL 5109）表现出抗真菌活性。七种真菌分离物的粗提物在 10mgml-1 浓度下对革兰氏阳性和革兰氏阴性细菌均表现出超过 11mm 的抑菌圈。青霉属、炭疽菌属、弯孢菌属、假尾孢菌属、腔孢菌纲和侧耳属是具有生物活性潜力的主要内生菌。这些结果表明，龙舌兰含有能够产生抗菌代谢物的内生微生物。
