Carvalho C R de, Ferreira-D'Silva A, Wedge D E, Cantrell C L, Rosa L H
a Department of Microbiology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, P.O. Box 486, CEP 31270-901, Brazil.
b Natural Products Utilization Research Unit, United States Department of Agriculture, Agricultural Research Service, University, MS 38677, USA.
Can J Microbiol. 2018 Nov;64(11):835-843. doi: 10.1139/cjm-2018-0131. Epub 2018 Jun 6.
In the present study, we evaluated the antifungal potential of cytochalasins produced by Diaporthe taxa against phytopathogenic fungi. Using molecular methods, seven endophytic fungal strains from the medicinal plants Copaifera pubiflora and Melocactus ernestii were identified as Diaporthe miriciae, while two isolates were identified to the genus level (Diaporthe sp.). All crude extracts of Diaporthe species produced via solid-state fermentation were evaluated by H NMR analyses. Crude extracts of the isolates D. miriciae UFMGCB 6350, 7719, 7646, 7653, 7701, 7772, and 7770 and Diaporthe sp. UFMGCB 7696 and 7720 were demonstrated to produce highly functionalized compounds. The extracts of D. miriciae UFMGCB 7719 and 6350 were selected as representative Diaporthe samples and subjected to bioassay-directed fractionation to isolate cytochalasins H and J. Cytochalasins H and J were evaluated for activities against the fungal plant pathogens Colletotrichum fragariae, Colletotrichum gloeosporioides, Colletotrichum acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and Phomopsis viticola using microdilution broth assays. Cytochalasins H and J exhibited the most potent activities against the Phomopsis species tested. Our results showed that Diaporthe species were potential producers of different cytochalasins, which exhibit potential for controlling fungal diseases in planta and (or) maintaining antagonism.
在本研究中，我们评估了座囊菌属类群产生的细胞松弛素对植物病原真菌的抗真菌潜力。利用分子方法，从药用植物柔毛巴西苏木和埃氏花座球中分离出的7株内生真菌菌株被鉴定为米氏座囊菌，而另外2株分离物仅鉴定到属水平（座囊菌属）。通过核磁共振氢谱（¹H NMR）分析对所有通过固态发酵产生的座囊菌属粗提物进行了评估。米氏座囊菌UFMGCB 6350、7719、7646、7653、7701、7772和7770以及座囊菌属UFMGCB 7696和7720的粗提物被证明能产生高度官能化的化合物。选择米氏座囊菌UFMGCB 7719和6350的提取物作为代表性座囊菌样品，并进行生物活性导向的分级分离以分离细胞松弛素H和J。使用微量稀释肉汤法评估细胞松弛素H和J对植物病原真菌草莓炭疽菌、胶孢炭疽菌、尖孢炭疽菌、灰葡萄孢、尖孢镰刀菌、暗拟茎点霉和葡萄生拟茎点霉的活性。细胞松弛素H和J对所测试的拟茎点霉属物种表现出最强的活性。我们的结果表明，座囊菌属是不同细胞松弛素的潜在生产者，这些细胞松弛素在控制植物真菌病害和（或）维持拮抗作用方面具有潜力。
