Finding of Pseudomonas mediterranea associated with P. corrugata on chrysanthemum plants in Sardinia

"In this study we have characterized 14 strains, 6 were Pseudomonas mediterranea e 8 P. corrugata, isolated from chrysanthemum plants grown in greenhouse located in the central-south of Sardinia. Infected chrysanthemum plantlets showed symptoms of rot and blight, and on blooming chlorosis and necrosis of leaves. In the pathogenicity tests all the strains tested were able to produce similar symptoms on chrysanthemum, tomato and pepper plants. Initially, the presence of two different species was ascertained by using different media. Among them, TZCAgar proved to be particularly suitable. The identification and the differentiation of the two species was confirmed by genomic analysis. According to multiplex PCR, performed with specific primers PC1\/1, PC1\/2 and PC5\/1, PC5\/2, the 6 strains of P. mediterranea showed the typical 600bp band, while the 8 strains of P. corrugate showed the typical 1100bp band. Cluster analysis of results of rep-PCR performed by using BOXA1R, and ERIC1R and ERIC2 primers, clustered the two species in two distinct groups. On the contrary Biolog phenotypic fingerprinting analysis identified the 14 strains in P. corrugata. However, P. mediterranea strains could be distinguished from P. corrugata strains on the basis of the metabolic profile determined by Biolog GEN III microplates. P. mediterranea is sensitive to lincomycin antibiotic and oxidize some sugars and organic acids including D- mannose, D-mannitol, L-glutamic acid, L-galactonic acid lactone. To determine their role in the disease, the two bacterial species are currently being tested in sperimental inoculations, alone or in combination, on chrysanthemum, geranium, pepper and tomato plants."