Actinomycetes come to rescue of viticulture sustainability

A great number of recent researches have shown that Actinomycetes can be considered as promising beneficial bacteria improving the growth and the capacity of the plants to face up both biotic and abiotic stresses. However, very few studies have been performed about the use of Actinomycetes in grapevine and all of them have focused their attention just on those isolated from the soil. For this reason, we decided to isolate bacteria from grapevine wood tissues characterizing a collection of 42 isolates, 27 of which belonging to the Actinobacteria phylum. These bacteria have been isolated from twenty years old grapevines without visual symptoms of wood diseases and subsequently used in dual culture assay against the main grape pathogens such as B. cinerea and the etiological agents of esca syndrome. Additionally, we are analysing antifungal effects of diffusible and volatile organic compounds (VOCs) produced by the isolates that previously showed a promising antagonistic activity against fungal pathogens. More studies are now ongoing to better understand their potential ability to promote plant growth features both in vitro and in vivo. Indeed, we are testing these bacteria on in vitro grapevine plants and on rooted cuttings. In the vitro assay we are evaluating their individual capacity to promote plant growth measuring the number of leaves and the roots length. Regarding to the rooted cuttings experiment, we inoculated a microbial consortium consisting of five Actinomycetes and three bacteria belonging to different phyla. The aim of the experiment is to test the effect of these beneficial bacteria both alone and in combination with some mycorrhizae fungi. We are now collecting several physiological parameters of the rooted cuttings to confirm the ability of these bacteria to increase the plant growth and wellness. More studies are needed but preliminary results display an interesting attitude of these actinomycetes as promising tool to improve viticulture sustainability.