Grapevine yellows (GY), a disease complex associated with phytoplasmas, induce severe crop losses and depreciate the wine quality, therefore their containment is a priority in the European wine producing areas. Up to now, none Vitis vinifera L. varieties have been found resistant to phytoplasma infection. In recent years, there has been an increasing interest about the recovery from GY diseases and in the role of endophytic bacteria as biocontrol agents. Endophytic bacteria can be termed all the bacteria colonizing the interior of plants without inducing diseases, including those that become pathogenic under certain conditions. Though their relationship with the host is not well understood, they may reduce the disease severity by activating systemic resistance, production of allelochemicals (biocidal volatiles, antibiotics, and lytic enzymes) and competition of nutrients and niches. Endophytic bacterial community associated with grapevine leaf tissues was characterized by cultivation-independent analyses (16S rRNA gene library and Length Heterogeneity-PCR) and cultivation methods. In order to identify endophytes directly from metagenome, a protocol for bacteria enrichment and DNA extraction was optimized. Library analysis of 16S rDNA showed best sequence matches with Proteobacteria, family Enterobacteriaceae, with a dominance of the genus Pantoea. More than 85% of the cloned sequences yielded best matches with the species Pantoea agglomerans. Bacteria isolation through cultivation showed best sequence matches with Curtobacterium, Stenotrophomonas, Methylobacterium, Pectobacterium, Enterobacter, Brevundimonas, Agrobacterium, Brevibacillus, Staphylococcus, Sphingomonas, Acaricomes, and Enterococcus. Specific electrophoretic peaks, associated with bacterial species identified in this study, were inserted in a reference LH-PCR database. The creation of this database was the first essential step for an extended large survey on bacterial diversity in vineyards in Italy. Preliminary data registered several additional peaks in healthy, phytoplasma-infected and recovered grapevine plants from Lombardy vineyards. Although bacteria identified in the present study probably do not represent the whole microbial diversity in grapevine plants, cultivation-independent approach could be used in order to compare endophytic bacterial communities in different ecological niches and to identify bacteria potential biocontrol agents of GY.

Endophytic bacteria living in grapevine plants under different phytosanitary conditions / D. Bulgari, P. Casati, P.A. Bianco. ((Intervento presentato al 18. convegno Congress of the International Organization for Mycoplasmology tenutosi a Chianciano Terme nel 2010.

Endophytic bacteria living in grapevine plants under different phytosanitary conditions

D. Bulgari
Primo
;
P. Casati
Secondo
;
P.A. Bianco
Ultimo
2010

Abstract

Grapevine yellows (GY), a disease complex associated with phytoplasmas, induce severe crop losses and depreciate the wine quality, therefore their containment is a priority in the European wine producing areas. Up to now, none Vitis vinifera L. varieties have been found resistant to phytoplasma infection. In recent years, there has been an increasing interest about the recovery from GY diseases and in the role of endophytic bacteria as biocontrol agents. Endophytic bacteria can be termed all the bacteria colonizing the interior of plants without inducing diseases, including those that become pathogenic under certain conditions. Though their relationship with the host is not well understood, they may reduce the disease severity by activating systemic resistance, production of allelochemicals (biocidal volatiles, antibiotics, and lytic enzymes) and competition of nutrients and niches. Endophytic bacterial community associated with grapevine leaf tissues was characterized by cultivation-independent analyses (16S rRNA gene library and Length Heterogeneity-PCR) and cultivation methods. In order to identify endophytes directly from metagenome, a protocol for bacteria enrichment and DNA extraction was optimized. Library analysis of 16S rDNA showed best sequence matches with Proteobacteria, family Enterobacteriaceae, with a dominance of the genus Pantoea. More than 85% of the cloned sequences yielded best matches with the species Pantoea agglomerans. Bacteria isolation through cultivation showed best sequence matches with Curtobacterium, Stenotrophomonas, Methylobacterium, Pectobacterium, Enterobacter, Brevundimonas, Agrobacterium, Brevibacillus, Staphylococcus, Sphingomonas, Acaricomes, and Enterococcus. Specific electrophoretic peaks, associated with bacterial species identified in this study, were inserted in a reference LH-PCR database. The creation of this database was the first essential step for an extended large survey on bacterial diversity in vineyards in Italy. Preliminary data registered several additional peaks in healthy, phytoplasma-infected and recovered grapevine plants from Lombardy vineyards. Although bacteria identified in the present study probably do not represent the whole microbial diversity in grapevine plants, cultivation-independent approach could be used in order to compare endophytic bacterial communities in different ecological niches and to identify bacteria potential biocontrol agents of GY.
12-lug-2010
Settore AGR/12 - Patologia Vegetale
International Organization for Mycoplasmology (IOM)
International Phytoplasmologist Working Group (IPWG)
Endophytic bacteria living in grapevine plants under different phytosanitary conditions / D. Bulgari, P. Casati, P.A. Bianco. ((Intervento presentato al 18. convegno Congress of the International Organization for Mycoplasmology tenutosi a Chianciano Terme nel 2010.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/148715
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