Tonial Fabiana, Maia Beatriz H L N S, Sobottka Andrea M, Savi Daiani C, Vicente Vânia A, Gomes Renata R, Glienke Chirlei
Instituto de Ciências Biológicas, Universidade de Passo Fundo, BR285, São José, Passo Fundo/RS, CEP: 99052-900, Brazil.
Patologia Básica, Universidade Federal do Parana, Av. Cel. Francisco H. dos Santos, 210, Curitiba, PR, 80060-000, Brazil.
FEMS Microbiol Lett. 2017 Mar 1;364(5). doi: 10.1093/femsle/fnx026.
Citrus black spot disease, caused by the phytopathogen Phyllosticta citricarpa, depreciates the market value of citrus fruits and prevents their exportation to disease-free regions. It may also reduce the productivity of citrus fruit orchards. To identify an alternative to conventional disease control measures, isolates of Diaporthe terebinthifolii, active against P. citricarpa, were selected from an endophytic fungal population of Schinus terebinthifolia leaves. Different culture media were screened to identify the culture medium that afforded the most efficient production of biologically active extracts. A particular fraction (fraction VI) of the extract completely protected orange leaves by inhibiting the germination of P. citricarpa conidia with a minimum inhibitory concentration of 0.003 μg.mL-1. The active constituents in D. terebinthifolii extract fractions were identified by gas chromatography coupled to mass spectrometry as verbanol, phenylethyl alcohol, verbenyl acetate and methyl hexadecanoate. The results obtained strongly suggest the existence of a synergistic effect among the metabolites produced. Thus, these fungal metabolites could be used to control the CBS disease. As the asexual spores of P. citricarpa play an important role in fruit lesion development and disease dispersion, fungal extracts that inhibit the spore germination can be used as an effective alternative for directional disease control.
柑橘黑点病由植物病原体柑橘叶点霉引起，会降低柑橘类水果的市场价值，并阻碍其向无病地区出口。它还可能降低柑橘果园的产量。为了找到传统病害控制措施的替代方法，从巴西胡椒树叶的内生真菌群体中筛选出了对柑橘叶点霉有活性的胡椒炭疽菌分离株。对不同的培养基进行了筛选，以确定能最有效地生产生物活性提取物的培养基。提取物的一个特定组分（组分VI）通过抑制柑橘叶点霉分生孢子的萌发，以0.003μg.mL-1的最低抑菌浓度完全保护了橙子树叶。通过气相色谱-质谱联用技术鉴定出胡椒炭疽菌提取物组分中的活性成分是马鞭草醇、苯乙醇、乙酸马鞭草酯和十六烷酸甲酯。所得结果有力地表明所产生的代谢物之间存在协同效应。因此，这些真菌代谢物可用于控制柑橘黑点病。由于柑橘叶点霉的无性孢子在果实病斑发展和病害传播中起重要作用，抑制孢子萌发的真菌提取物可作为定向病害控制的有效替代方法。
