The cultivation of açai palm, which yields tasteful and nutritional fruits, has been stimulated by the high commercial values of açai pulps; however, the occurrence of anthracnose (a disease caused by the fungus Colletotrichum gloeosporioides) on açaí nursery and orchards has been a challenge for the shift from açaí extractivism to its cultivation. The interaction among endophytic fungi and host can change the plant disease severity, facilitating infection by phytopathogens and increasing its damage to plants. Therefore, this study aimed to investigate the antagonistic activity of five endophytic fungi against C. gloeosporioides, as well as to evaluate the anthracnose severity in açaí seedlings in response to the inoculation of the most promising of the tested endophytic fungus. First, in vitro evaluation showed that most of the fungi were able to grow over C. gloeosporioides mycelia. The endophytic fungi Graphium sp. 2.4765 and Hypoxylon anthochroum 2.4996 recorded the highest rates of growth inhibition, 79.3% and 77.0%, respectively. Because H. anthochroum 2.4996 presented better in vitro growth and spore production, it was chosen for subsequent evaluations. Second, in planta evaluation showed that the inoculation of H. anthochroum 2.4996 in diseased plants enhanced both the necrotic area in leaflets and disease symptoms. Third, comparative analyses based on the cultural, micromorphological and molecular characteristics have shown that such strain is related to H. anthochroum. Overall, this study highlights the complexity of the plant–microbe interactions.

中文翻译：

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内生真菌 Hypoxylon anthochroum 菌株 2.4996 对巴西莓幼苗炭疽病严重程度的影响

巴西莓果肉的高商业价值刺激了巴西莓棕榈的种植，这种棕榈可产出美味且营养的水果；然而，巴西莓苗圃和果园发生炭疽病（一种由胶孢炭疽菌引起的疾病），对巴西莓采掘业向种植业的转变构成了挑战。内生真菌与寄主之间的相互作用可以改变植物病害的严重程度，促进植物病原体的感染并增加其对植物的损害。因此，本研究旨在研究五种内生真菌对胶孢炭疽菌的拮抗活性，并评估巴西莓幼苗接种最有希望的内生真菌后炭疽病的严重程度。首先，体外评估表明大多数真菌能够在胶孢梭菌菌丝体上生长。内生真菌Graphium sp。2.4765和Hypoxylon anthochroum 2.4996记录了最高的生长抑制率，分别为79.3%和77.0%。由于H. anthochroum 2.4996 表现出更好的体外生长和孢子产生，因此选择它进行后续评估。其次，植物内评估表明，在患病植物中接种H. anthochroum 2.4996 可以增强小叶的坏死面积和疾病症状。第三，基于培养、微形态和分子特征的比较分析表明该菌株与H. anthochroum有亲缘关系。总的来说，这项研究强调了植物与微生物相互作用的复杂性。