Pseudomonas viridiflava, a Multi Host Plant Pathogen with Significant Genetic Variation at the Molecular Level

Abstract

The pectinolytic species Pseudomonas viridiflava has a wide host range among plants, causing foliar and stem necrotic lesions and basal stem and root rots. However, little is known about the molecular evolution of this species. In this study we investigated the intraspecies genetic variation of P. viridiflava amongst local (Cretan), as well as international isolates of the pathogen. The genetic and phenotypic variability were investigated by molecular fingerprinting (rep-PCR) and partial sequencing of three housekeeping genes (gyrB, rpoD and rpoB), and by biochemical and pathogenicity profiling. The biochemical tests and pathogenicity profiling did not reveal any variability among the isolates studied. However, the molecular fingerprinting patterns and housekeeping gene sequences clearly differentiated them. In a broader phylogenetic comparison of housekeeping gene sequences deposited in GenBank, significant genetic variability at the molecular level was found between isolates of P. viridiflava originated from different host species as well as among isolates from the same host. Our results provide a basis for more comprehensive understanding of the biology, sources and shifts in genetic diversity and evolution of P. viridiflava populations and should support the development of molecular identification tools and epidemiological studies in diseases caused by this species.

Genetic and pathogenic diversity of Pseudomonas syringae strains isolated from cucurbits

“…They appear to provide a sound method for classification of Pseudomonas strains isolated from cucumber. The gyrB-based phylogenetic tree for the local isolates was topologically almost identical to the tree based on the rep-PCR fingerprinting, while the phylogenetic tree based on the rpoB and rpoD gene sequences revealed clearly different patterns of variation (Sarris et al 2012). Our results indicate that although the gyrB is indeed one of the best markers for P.syringae pv.…”

Diversity among Pseudomonas corrugata and Pseudomonas mediterranea isolated from tomato and pepper showing symptoms of pith necrosis in Greece

“…However, several bacterial species have been reported to cause Solanaceae ‘pith necrosis’ in Greece, including P. cichorii (Trantas et al ., ), P. corrugata (Alivizatos, ), P. viridiflava (Malathrakis & Goumas, ; Sarris et al ., ) and P . fluorescens (Malathrakis & Goumas, ), and also members of the Pectobacterium genus (previously named Erwinia ) P. atrosepticum and P. carotovorum (Malathrakis & Goumas, ), and Dickeya chrysanthemi (Alivizatos, ).…”

“…The initial screening of 72 bacterial strains from the TEIC bacterial collection revealed that 32 of them exhibited the characteristic P. corrugata wrinkled colony formation when grown on NA supplemented with 1% glucose, and these were subjected to further biochemical and phytopathological characterization. The remaining bacterial isolates belonged mainly to P. viridiflava and P. cichorii species and have been characterized previously from this group (Sarris et al ., ; Trantas et al ., ).…”

“…Greenhouse‐cultivated tomato and pepper are two of the most important crops for the Cretan economy, with losses ranging from 2 to 10% of cultivated plants in plastic covered greenhouses during winter, although under certain conditions this can rise to over 20% (Malathrakis & Goumas, ). Because pith necrosis of Solanaceae is a serious threat for the Cretan commercial fields, previous work has tried to elucidate the underlying intra‐ and interspecific genetic variability of P. viridiflava (Sarris et al ., ) and P. cichorii (Trantas et al ., ) pathogens. The current work aims to screen and characterize bacterial isolates from tomato and pepper plants displaying pith necrosis symptoms from around the island of Crete from samples collected over a period of 20 years.…”

The Pseudomonas viridiflava phylogroups in the P. syringae species complex are characterized by genetic variability and phenotypic plasticity of pathogenicity‐related traits

“…In contrast to the well‐established heterogeneity within phylogroups of P. syringae , P. viridiflava has been reported to be relatively homogeneous (Sarris et al ., ). Although designated with a species name, P. viridiflava represents one of the multiple phylogroups found within the P. syringae species complex (Gardan et al ., ; Mulet et al ., ; Parkinson et al ., ).…”