title: Plant growth promotion potential is equally represented in diverse grapevine root-associated bacterial communities from different biopedoclimatic environments.
abstract: Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP) potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P = 0.03) and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23%) presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%), insoluble phosphate solubilisation (61%), and ammonia production (70%). The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root.
authors.affiliation: Department of Food, Environment, and Nutritional Sciences, University of Milan, Via Celoria 2, 20133 Milan, Italy.
authors.forename: Ramona
authors.initials: R
authors.lastname: Marasco
authors.forename: Eleonora
authors.initials: E
authors.lastname: Rolli
authors.forename: Marco
authors.initials: M
authors.lastname: Fusi
authors.forename: Ameur
authors.initials: A
authors.lastname: Cherif
authors.forename: Ayman
authors.initials: A
authors.lastname: Abou-Hadid
authors.forename: Usama
authors.initials: U
authors.lastname: El-Bahairy
authors.forename: Sara
authors.initials: S
authors.lastname: Borin
authors.forename: Claudia
authors.initials: C
authors.lastname: Sorlini
authors.forename: Daniele
authors.initials: D
authors.lastname: Daffonchio
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D002980:Climate; D019083:Mediterranean Region; D059013:Microbial Consortia / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development* / Q000382:microbiology*; D027843:Vitis / Q000254:growth & development* / Q000382:microbiology*