Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. vanillae (Fov), is a disease that results in significant losses in commercial vanilla production. The genera Ceratobasidium (Ceratobasidiaceae) and Tulasnella (Tulasnellaceae), which are often reported as mutualistic symbionts in orchids, belong to the form genus Rhizoctonia, a paraphyletic group of fungi with potential for pathogen biocontrol. We assayed the antagonistic properties of the form genus Rhizoctonia from the roots of neotropical orchids: two Tulasnella spp. isolates (Bv3 and Er1) and one Ceratobasidium sp. (Er19). In a dual culture, we found that form genus Rhizoctonia isolates can generate a biocontrol effect against Fusarium through the mechanisms of antibiosis and competition for space and nutrients. On histological observations, orchid root endophytes also demonstrated potential for mutualistic symbiosis development by establishing themselves on the surface and within the root tissue of Vanilla planifolia accessions multiplied in vitro (NSF021 and NSF092). However, in plant assays, the form genus Rhizoctonia isolates did not reduce symptom expression or disease development due to infection by Fov in the host. These results contribute to the knowledge of the interactions between tropical orchids and their microbiota and demonstrate the need for multidisciplinary studies for the implementation of integrated management strategies for Fusarium disease in commercial systems.

Vanilla is an economically important crop for low‐lying humid tropical regions, but cultivated plants face serious phytosanitary problems. Fusarium wilt is a devastating disease affecting vanilla crops, caused by the fungal pathogens Fusarium oxysporum f. sp. vanillae (Fov) and F. oxysporum f. sp. radicis‐vanillae (Forv), part of the F. oxysporum species complex (FOSC). We characterized 29 fungal isolates from a vanilla crop and crop wild relatives (CWR) using molecular (EF1‐α and ITS‐rRNA loci) and morphological traits. Fusarium was the predominant genus, followed by Colletotrichum and Clonostachys . Four Fusarium species were identified: F. oxysporum (37.9%), Fusarium solani (20.7%), Fusarium pseudocircinatum (13.8%) and Fusarium concentricum (10.3%). The latter three species were isolated only from CWR and may represent latent pathogens. Fov was isolated from both the crop and CWR, while a Forv‐affiliated isolate was also found in a vanilla crop, marking the first report in the neotropical region. The EF1‐α locus provided greater genotype resolution, as well as having reference sequences for Forv. However, the fungal barcode ITS locus is widely applied. We recommend the continued use of both loci for Fusarium diagnosis in vanilla to facilitate early detection and the development of effective integrated crop management strategies.

En esta revisión se exponen de forma general las características del metabolismo del orden Anura (Fischer von Waldheim, 1813), reportadas desde mediados del siglo XX hasta la actualidad. Los Anura son calificados como organismos exitosos por poseer una amplia gama de mecanismos de adaptación a diferentes situaciones de estrés, posibles causas de la alta diversidad en este grupo. Se mencionan algunas adaptaciones en el proceso de asimilación de los carbohidratos con sus respectivos componentes fisiológicos, destacando la importancia de los corticosteroides en la activación de varias rutas metabólicas y la regulación de estos a través de factores como la temperatura y la estación anual. Se describen las principales funciones de los lípidos, las particularidades de las membranas y estrategias para eludir el estrés oxidativo, así como las adaptaciones del metabolismo de los compuestos nitrogenados y el almacenamiento de diversos alcaloides, la urea y su importancia en la osmorregulación posterior a la metamorfosis. Finalmente, se plantean perspectivas respecto a futuras investigaciones sobre la bioquímica de estos organismos.