The olive knots represent an ideal niche not only for the growth of Pseudomonas savastanoi pv. savastanoi (Pss) but also for a number of endophytic bacteria such as Erwinia toletana, Pantoea agglomerans and others belonging to the genus Burkholderia, Hafnia and Stenotrophomonas. In 2003 and 2007, 3 Erwinia-like strains were isolated inside olive knots collected in Central (Umbria) and South (Apulia) Italy, whose 16S rDNA gene sequences have high similarity (> 99 %) with the strains CECT 5262 and CECT 5264 isolated in Spain from olive knots and provisionally assigned to Pantoea oleae. Since the Italian and Spanish strains showed very high similarity (≥ 88 %) when subjected to rep-PCR, using the primers BOX, ERIC and REP, they were subjected to a polyphasic taxonomic study that included DNA-DNA hybridization, DNA base ratio determination, multilocus sequence analysis (MLSA) based on concatenated partial atpD, gyrB, infB and rpoB gene sequences and biochemical characterization. Based on the genotypic and the phenotypic data, we proposed to classify the five Italian and Spanish endophytic bacterial strains from olive knots into a novel species and the name Erwinia oleae sp. nov. is suggested. E. oleae could be collaborate with Pss in olive knot disease development as it: i) produces in vitro detectable levels of indole-3-acetic acid (IAA); ii) bears genes involved in IAA and cytokinin biosyntheses; iii) increases disease severity when inoculated in olive plants together with Pss.
Possible role of Erwinia oleae sp. nov. in the development of olive knots caused by Pseudomonas savastanoi pv. savastanoi.
MORETTI, Chiaraluce;BUONAURIO, Roberto
2010
Abstract
The olive knots represent an ideal niche not only for the growth of Pseudomonas savastanoi pv. savastanoi (Pss) but also for a number of endophytic bacteria such as Erwinia toletana, Pantoea agglomerans and others belonging to the genus Burkholderia, Hafnia and Stenotrophomonas. In 2003 and 2007, 3 Erwinia-like strains were isolated inside olive knots collected in Central (Umbria) and South (Apulia) Italy, whose 16S rDNA gene sequences have high similarity (> 99 %) with the strains CECT 5262 and CECT 5264 isolated in Spain from olive knots and provisionally assigned to Pantoea oleae. Since the Italian and Spanish strains showed very high similarity (≥ 88 %) when subjected to rep-PCR, using the primers BOX, ERIC and REP, they were subjected to a polyphasic taxonomic study that included DNA-DNA hybridization, DNA base ratio determination, multilocus sequence analysis (MLSA) based on concatenated partial atpD, gyrB, infB and rpoB gene sequences and biochemical characterization. Based on the genotypic and the phenotypic data, we proposed to classify the five Italian and Spanish endophytic bacterial strains from olive knots into a novel species and the name Erwinia oleae sp. nov. is suggested. E. oleae could be collaborate with Pss in olive knot disease development as it: i) produces in vitro detectable levels of indole-3-acetic acid (IAA); ii) bears genes involved in IAA and cytokinin biosyntheses; iii) increases disease severity when inoculated in olive plants together with Pss.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
