70 research outputs found
Naturally occurring non cerato-ulmin producing mutants of Ophiostoma novo-ulmi are pathogenic but lack aerial mycelium
TRANSGENIC TRANSIENT EXPRESSION AS A TOOL TO ASSESS THE EFFICACY OF SHORT PEPTIDES TO CONTROL BACTERIAL DISEASES
Alien pest molecular diagnostics: can DNA traces be exploited to assess the damage caused by the western conifer seed bug on stone pine fructification?
Detection of phytoplasmal DNA in flowers and seeds from elm trees infected with Elm Yellows
The occurrence of phytoplasmas associated with Elm Yellows (EY) was investigated in the reproductive
structures (flowers, unripe and ripe fruits) of two EY-infected trees of the hybrid elm clone Lobel and two healthy
trees, an Ulmus laevis and an U. japonica. Phytoplasma group-specific Polymerase Chain Reaction (PCR), restriction
fragment length polymorphism analysis and sequencing of amplified fragments were carried out using as template
DNA extracted from these reproductive structures. The flowers and fruits were dissected into parts (the flowers into
anthers and ovaries, the fruits into seeds and membranaceous wings), and then examined separately. A total of 350
seeds from infected trees were sown, producing 24 plantlets, which were sampled for EY phytoplasma DNA one and
five months after germination. Both flowers and seeds from the EY-infected trees were good sources for the extraction
and PCR-amplification of EY phytoplasmas, but no EY phytoplasmas were detected in either the flowers and seeds of
the two healthy trees or in samples collected from the 24 plantlets grown from seed
Phenotypic and Molecular-Phylogenetic Analysis Provide Novel Insights into the Diversity of Curtobacterium flaccumfaciens.
A multiphasic approach was used to decipher the phenotypic features, genetic diversity, and phylogenetic position of 46 Curtobacterium spp. strains isolated from dry beans and other annual crops in Iran and Spain. Pathogenicity tests, resistance to arsenic compounds, plasmid profiling and BOX-PCR were performed on the strains. Multilocus sequence analysis (MLSA) was also performed on five housekeeping genes (i.e., atpD, gyrB, ppk, recA, and rpoB) of all the strains, as well as five pathotype strains of the species. Pathogenicity test showed that six out of 42 strains isolated in Iran were nonpathogenic on common bean. Despite no differences found between pathogenic and nonpathogenic strains in their plasmid profiling, the former were resistant to different concentrations of arsenic, while the latter were sensitive to the same concentrations. Strains pathogenic on common bean were polyphyletic with at least two evolutionary lineages (i.e., yellow-pigmented strains versus red/orange-pigmented strains). Nonpathogenic strains isolated from solanaceous vegetables were clustered within either the strains of C. flaccumfaciens pv. flaccumfaciens or different pathovars of the species. The results of MLSA and BOX-PCR analysis were similar to each other and both methods were able to discriminate the yellow-pigmented strains from the red/orange-pigmented strains. A comprehensive study of a worldwide collection representing all five pathovars as well as nonpathogenic strains of C. flaccumfaciens is warranted for a better understanding of the diversity within this phytopathogenic bacterium
NICOTIANA LANGSDORFFII TRANSGENIC PLANTS WITH MODIFIED HORMONAL METABOLISM AS A MODEL SYSTEM FOR THE STUDY OF PHYTOPATOGENIC BACTERIA-PLANTS INTERACTION
Indole-3-acetic acid in plant-pathogen interactions: a key molecule for in planta bacterial virulence and fitness
AN INTEGRATED MODEL SYSTEM TO INVESTIGATE THE EFFECT OF COPPER ON PLANT PATHOGEN INTERACTION.
High-Resolution Melting Analysis as a Powerful Tool to Discriminate and Genotype Pseudomonas savastanoi Pathovars and Strains
Pseudomonas savastanoi is a serious pathogen of Olive, Oleander, Ash, and several other Oleaceae. Its epiphytic or endophytic presence in asymptomatic plants is crucial for the spread of Olive and Oleander knot disease, as already ascertained for P. savastanoi pv. savastanoi (Psv) on Olive and for pv. nerii (Psn) on Oleander, while no information is available for pv. fraxini (Psf) on Ash. Nothing is known yet about the distribution on the different host plants and the real host range of these pathovars in nature, although cross-infections were observed following artificial inoculations. A multiplex Real-Time PCR assay was recently developed to simultaneously and quantitatively discriminate in vitro and in planta these P. savastanoi pathovars, for routine culture confirmation and for epidemiological and diagnostical studies. Here an innovative High-Resolution Melting Analysis (HRMA)-based assay was set up to unequivocally discriminate Psv, Psn and Psf, according to several single nucleotide polymorphisms found in their Type Three Secretion System clusters. The genetic distances among 56 P. savastanoi strains belonging to these pathovars were also evaluated, confirming and refining data previously obtained by fAFLP. To our knowledge, this is the first time that HRMA is applied to a bacterial plant pathogen, and one of the few multiplex HRMA-based assays developed so far. This protocol provides a rapid, sensitive, specific tool to differentiate and detect Psv, Psn and Psf strains, also in vivo and against other related bacteria, with lower costs than conventional multiplex Real-Time PCR. Its application is particularly suitable for sanitary certification programs for P. savastanoi, aimed at avoiding the spreading of this phytopathogen through asymptomatic plants
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