Authors: I ArjonaGirona T ArizaFernández C J LópezHerrera
Publish Date: 2016/10/27
Volume: 148, Issue: 1, Pages: 109-117
Abstract
By transversely cutting infected avocado plant stems and using PCR techniques on avocado leaves two experiments were carried out to determine whether Rosellinia necatrix can invade avocado vascular tissues We were unable to detect the pathogen in either stems or leaves in either experiment so we concluded that R necatrix does not invade the vascular system of the plant Additionally the toxins produced by the pathogen were also studied to determine whether such toxins could contribute to the wilting and death of avocado plants infected by R necatrix having an effect on avocado leaves where they can hinder the photosynthetic process First we isolated and identified the toxins cytochalasin E and rosnecatrone from filtrates of six R necatrix isolates Second we tried to detect cytochalasin E in sap and leaves from infected avocado plants and it was not detected at the minimum level of 50 μg/kg in leaves or 25 μg/kg on sap Finally we observed changes in fluorescence emitted by the avocado leaf surface to detect photosynthetic efficiency after inoculating avocado plants with this toxin Fluorescence was higher in the leaves of plants immersed in toxin solution after 4 and 8 days but not after longer periods of time In this work we demonstrated that although R necatrix is not a fungus that invades the vascular system its toxins are probably involved in the wilting and death of infected avocado plants decreasing the efficiency of photosynthesisThis research was supported by the “Consejería de Innovación Ciencia y Empresa” Junta de Andalucía grant Grupo PAIDI AGR235 and by the Plan Nacional I + D + I from Ministerio de Ciencia e Innovación AGL 2011030354CO202 In addition this research was cofinanced by FEDER funds EUThe authors thank Prof Anthony JS Whalley Liverpool John Moores University School of Pharmacy and Biomolecular Sciences UK and Prof Dereck Maitland Bradford University UK for their support to the first author in learning the techniques of toxin purification
Keywords: