Abstract

DUQUE-BAUTISTA, Horacio; ZURITA-VASQUEZ, Guilibaldo Gabriel; PACHECO-HERNANDEZ, Yesenia  and  VILLA-RUANO, Nemesio. Etiology of a black spot symptom in Agave angustifolia: An in vitro approach towards its biological control. Rev. mex. fitopatol [online]. 2017, vol.35, n.2, pp.326-337. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1701-2.

We present the molecular identification of a Cladosporium species isolated from necrotic spots of diseased stalks of Agave angustifolia, which were collected in San Luis Amatlán, Oaxaca, Mexico. Analyses of the internal transcribed spacer (ITS) from the 18S ribosomal RNA gene and the partial coding region (cDNA) from an allergenic conserved heat shock protein 70 (HSP70), revealed its similarity with Cladosporium herbarum (Pers.: Fr.) Link. The in vitro assessment of the ethanolic extracts from Zaluzania montagnifolia roots and its main ent-kaurenoids resulted in the growth inhibition of the fungus. Minimum inhibitory concentration (MIC) values were obtained by the agar dilution and broth microdilution methods. The ethanolic extract, ent-kaurenoic acid (ent16-kauren-19-oic acid) and grandiflorenic acid (ent-kaur-9(11),16-dien-19-oic acid) showed MIC values of 150.4±3.5, 100.3±2.1, and 80.7±1.4 μg mL-1, respectively.

Keywords : Cladosporium herbarum; ITS; maguey mezcalero; ent-kaurene derivatives; growth inhibition.