Immature walnut fruit inoculation for evaluation of Brenneria nigrifluens pathogenicity

A reliable, reproducible, rapid and specific test for the pathogenicity of Brenneria nigrifluens, the causal agent of shallow bark canker of Persian walnut, was developed. When the mesocarp of immature walnut fruits was infiltrated by syringe with bacterial suspensions (108 cells mL-1) of B. nigrifluens, necrosis and reddish brown exudates started to appear at the inoculation sites, as early as 2 days after inoculation. No symptoms were detected in control fruits or in fruits inoculated with other bacteria frequently associated with walnut cankers. This pathogenicity test saves time and space when compared with the plant stem inoculation technique, in which the canker symptoms do not appear until at least 1 month after inoculation.&nbsp

Erwinia oleae sp. nov., isolated from olive knots caused by Pseudomonas savastanoi pv. savastanoi

Three endophytic bacterial isolates were obtained in Italy from olive knots caused by Pseudomonas savastanoi pv. savastanoi. Phenotypic tests in combination with 16S rRNA gene sequence analysis indicated a phylogenetic position of these isolates in the genus Erwinia or Pantoea, and revealed two other strains with highly similar 16S rRNA gene sequences (> 99 %), CECT 5262 and CECT 5264, obtained in Spain from olive knots. Rep-PCR DNA fingerprinting of the five strains from olive knots with BOX, ERIC and REP primers revealed three groups of profiles that were highly similar to each other. Multilocus sequence analysis (MLSA) based on concatenated partial atpD, gyrB, infB and rpoB gene sequences, indicated that the strains constitute a single novel species in the genus Erwinia. The strains showed general phenotypic characteristic of Erwinia, and whole genome DNA-DNA hybridization data confirmed they represent a single novel Erwinia species. The strains showed a DNA G+C base composition ranging from 54.7 to 54.9 mol%. They could be discriminated from the phylogenetically related Erwinia species by their ability to utilise potassium gluconate, L-rhamnose and D-arabitol, but not glycerol, inositol and D-sorbitol. The name Erwinia oleae (type strain DAPP-PG 531T = LMG 25322T = DSM 23398T) is proposed for this new taxon

Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses

Occurrence of a soft rot of calla («Zantedeschia aethiopica») caused by «Pectobacterium carotovorum» subsp. «carotovorum» in central Italy

Pectobacterium carotovorum subsp. carotovorum causing soft rot of calla (Zantedeschia aethiopica) plants is reported in central Italy. Bacterial isolates were identified by biochemical, physiological and pathogenicity tests and characterized by the API 50 CHE Kit and rep-PCR

Cloning and expression analysis of a Petunia hybrida flower specific mitotic-like cyclin

AbstractA cyclin cDNA clone (Pethy;CycB1;1) was isolated from a Petunia hybrida ovary specific cDNA library. Sequence comparison revealed that Pethy;CYCB1;1 protein is highly homologous to mitotic B1 cyclins. Northern analysis and in situ hybridisation experiments showed that its expression is developmentally regulated and restricted to flower organs. We have attempted to define some of the cell division patterns which contribute to shaping each floral organ by analysing Pethy;CycB1;1 expression on Petunia flower sections. While in sepals, epidermis and parenchyma cell division patterns were comparable, there were two distinct cell division patterns in petals. In the epidermis, Pethy;CYCB1;1 expression was found both at the petal tip and along epidermis, whereas in the parenchyma only at the petal tips. In reproductive organs cell divisions were detected only in sporophytic tissues. No signals were detected inside meiotic cells

Host range determinants of Pseudomonas savastanoi pathovars of woody hosts revealed by comparative genomics and cross-pathogenicity tests

The study of host range determinants within the Pseudomonas syringae complex is gaining renewed attention due to its widespread distribution in non-agricultural environments, evidence of large variability in intra-pathovar host range, and the emergence of new epidemic diseases. This requires the establishment of appropriate model pathosystems facilitating integration of phenotypic, genomic and evolutionary data. Pseudomonas savastanoi pv. savastanoi is a model pathogen of the olive tree, and here we report a closed genome of strain NCPPB 3335, plus draft genome sequences of three strains isolated from oleander (pv. nerii), ash (pv. fraxini) and broom plants (pv. retacarpa). We then conducted a comparative genomic analysis of these four new genomes plus 16 publicly available genomes, representing 20 strains of these four P. savastanoi pathovars of woody hosts. Despite overlapping host ranges, cross-pathogenicity tests using four plant hosts clearly separated these pathovars and lead to pathovar reassignment of two strains. Critically, these functional assays were pivotal to reconcile phylogeny with host range and to define pathovar-specific genes repertoires. We report a pan-genome of 7,953 ortholog gene families and a total of 45 type III secretion system effector genes, including 24 core genes, four genes exclusive of pv. retacarpa and several genes encoding pathovar-specific truncations. Noticeably, the four pathovars corresponded with well-defined genetic lineages, with core genome phylogeny and hierarchical clustering of effector genes closely correlating with pathogenic specialization. Knot-inducing pathovars encode genes absent in the canker-inducing pv. fraxini, such as those related to indole acetic acid, cytokinins, rhizobitoxine, and a bacteriophytochrome. Other pathovar-exclusive genes encode type I, type II, type IV, and type VI secretion system proteins, the phytotoxine phevamine A, a siderophore, c-di-GMP-related proteins, methyl chemotaxis proteins, and a broad collection of transcriptional regulators and transporters of eight different superfamilies. Our combination of pathogenicity analyses and genomics tools allowed us to correctly assign strains to pathovars and to propose a repertoire of host range-related genes in the P. syringae complex.AM-P, AP, CR, and JM were supported by grants FPI/BES-2015-074847, FPU14/05551, AGL2017-82492-C2-1-R and AGL2017-82492-C2-2-R, respectively, from Ministerio de Ciencia, Innovacion y Universidades (Spain), cofinanced by the Fondo Europeo de Desarrollo Regional (FEDER); CM was supported by DSA3 research funds “Fondo di base” (Italy)

A microseismic study in a low seismicity area of Italy: the Città di Castello 2000-2001 experiment

Recent seismological studies contribute to better understand the first order characteristics of earthquake occurrence in Italy, identifying the potential sites for moderate to large size earthquakes. Ad hoc passive seismic experiments performed in these areas provide information to focus on the location and geometry of the active faults more closely. This information is relevant for assessing seismic hazard and for accurately constraining possible ground shaking scenarios. The area around the Città di Castello Basin, in the Northern Apennines (Central Italy), is characterized by the absence of instrumental seismicity (M > 2.5), it is adjacent to faults ruptured by recent and historical earthquakes. To better understand the tectonics of the area, we installed a dense network of seismic stations equipped with broadband and short period seismometers collecting data continuously for 8 months (October 2000-May 2001). The processing of ~ 900 Gbyte of data revealed a consistent background seismicity consisting of very low magnitude earthquakes (ML < 3.2). Preliminary locations of about 2200 local earthquakes show that the area can be divided into two regions with different seismic behaviour: an area to the NW, in between Sansepolcro and Città di Castello, where seismicity is not present. An area toward the SE, in between Città di Castello, Umbertide and Gubbio, where we detected a high microseismicity activity. These findings suggest a probable different mechanical behaviour of the two regions. In the latter area, the seismicity is confined between 0 and 8 km of depth revealing a rather well defined east-dipping, low angle fault 35 km wide that cuts through the entire upper crust down to 12-15 km depth. Beside an apparent structural complexity, fault plane solutions of background seismicity reveal a homogeneous pattern of deformation with a clear NE-SW extension

Integrated SEED data archive for temporary seismic experiments

One of the most valuable results achieved during the work on S5 project is the implementation of a new temporary network data management that allows the integration in the National Data Center together with all other seismological data produced by INGV. This makes all data gathered during temporary experiments immediately available from the same source and in the same data format (SEED) increasing the availability for processing and analysis. Moreover the data are distributed to the scientific community using the EIDA (European Integrated Data Archive http://eida.rm.ingv.it/). The first application has been carried out for the Messina 1908-2008 experiment (WP2.2) http://dpc-s5.rm.ingv.it/en/Database-MessinaFault.html where has been achieved the complete integration of permanent networks (National Seismic Network, MedNet and Peloritani Local Network), temporary deployments (INGV-CNT and INGVCT mobile networks) and OBS data. All the procedures were used and further improved during the L'Aquila sequence (Task 4) where data was available for processing together with permanent network data as soon as it was gathered from the field giving to the scientific community the opportunity to study the evolution of the seismic sequence with higher density of stations (WP4.2) ( h t t p : / / d p c - s 5 . r m . i n g v . i t / e n / D a t a b a s e - AquilaFaultSystem.html).UnpublishedSede Ispra | Via Curtatone 7, Roma1.1. TTC - Monitoraggio sismico del territorio nazionaleope