Fusarium head blight: Chemical signals of early infection.

GIROTTI JUAN R.; MALBRAN ISMAEL; LORI GLADYS ; JUÁREZ M PATRICIA

Colonia

Congreso; Primer Congreso de la Asociación Latinoamericana de Ecología Química (ALAEQ); 2010

Asociación Latinoamericana de Ecología Química (ALAEQ)

Fusarium head blight: Chemical signals of early infection. Girotti J R 1, Malbrán I 2, Lori G A 2 and Juárez M P 1 E-mail: mjuarez@isis.unlp.edu.ar 1Instituto de Investigaciones Bioquímicas de La Plata (CCT-CONICET-UNLP) Facultad de Ciencias Médicas, calles 60 y 120 1° piso, CP 1900, La Plata, Argentina. 2 Centro de investigaciones de Fitopatología (CIC-UNLP). Facultad de Ciencias Agrarias y Forestales, calle 60 y 119, CP 1900, La Plata, Argentina. In Argentina, Fusarium head blight (FHB) is a major destructive disease of wheat and other cereal cultivars. Fusarium species infect wheat during the flowering period; in addition to losses of yield, mycotoxins produced by these fungi in suitable environmental conditions, can threaten animal and human health. Fungi produce volatile organic compounds (VOC), during both primary and secondary metabolism, VOC appear as intermediate and end products of various metabolic pathways, among them mono- and sesquiterpenes, alcohols, ketones, lactones, esters or C8 compounds, can be used for their detection and identification. Solid phase microextraction (SPME) coupled to capillary gas chromatography (CGC) and mass spectrometry (MS) was used to study its potential to detect volatile precursors of mycotoxins released by Fusarium graminearum either grown in culture medium or in wheat plants [1]. The aim was to develop a new tool to predict Fusarium head blight in wheat cultivars grown in greenhouse or in the field. We also investigated the utility of fungal volatiles to discriminate Fusarium species. The chromatographic profile of F. graminearum VOC showed a variety of sesquiterpenes, including trichodiene, major precursor in the synthesis of trichothecene mycotoxins; together with minor amounts of short chain alcohols, esters, ketones, and hydrocarbons. When wheat cultivars in greenhouse or experimental field assays were artificially infected, trichodiene was detected within 24h after fungal infection, before disease signals are evident. The VOC sesquiterpene pattern of F. graminearum, F. poae, F. equiseti, F. verticillioides and F.oxysporum was useful in their differentiation. Trichotecene-producer and non-trichotecene producer Fusarium spp. were separated by the presence of trichodiene in their VOC fingerprints. We conclude that this technique is helpful to detect F. graminearum, the major head blight disease-producing fungi in the region. [1] Girotti, J.R., Malbrán, I., Lori, G. A., Juárez, M.P. 2008. Método para la detección temprana de infecciones fúngicas en plantas cultivables, método para evaluar la efectividad de un tratamiento antifungico y procedimiento”, Patente solicitud Nº P-080104942 (INPI, Argentina). This work was supported by the National Agency for Science and Technology Promotion in Argentina (PICT 2004-20-25479). M. P. Juárez is member of CONICET Researcher’s Career. G. A. Lori is member of the CIC Researcher’s Career.