Antagonism of the endophytic Bacillus subtilis strain AG1 to fungal pathogens that cause tracheomycotic deterioration of wine wood

Abstract

Grapevine trunk diseases can determine considerable losses in the worldwide wine industry. Symptoms of wood diseases are dead spurs, arms, cordons and same times vine death, due to cankers in the vascular tissue (Pascoe, 2000). Recent research has also showed a recrudescence either of escadisease or decay by Verticilliumdahliae and the occurrence of new wood alterations (Botryosphaeriarhodina; Mugnai et al., 1999; Wood et al., 2005; Bonfiglioliet al., 2007). Last investigations, carried out in Sicilian vineyards on fungi associated with xilematic“esca”symptoms, revealed the occurrence of genus Bacillusin wood tissues. A spore-producer Gram-positive bacterial isolate, named AG1, was identified as Bacillus subtilissubsp. subtilis,on the basis of the partial 16S rRNAsequence comparison. Previous study relived for the first time the antagonism of B. subtilistowards fungi of “esca”disease (Alfonzo et al., 2007). Direct and indirect assays, in fact, showed a considerable biocontrolof AG1 towards Phaeoacremoniumaleophilum(PAL) and Phaeomoniellachlamydospora(PCH). In order to confirm the bio-activity of AG1, the crude antibiotic extract was tested againstthe most common tracheomycoticfungi of grapevine.