A roadmap of tissue culture and biotechnology in European hazelnut (Corylus avellana L.)

The increasing interest in European hazelnut (Corylus avellana L.) cultivation registered in the last years has led to a significant increase in worldwide hazelnut growing areas, also involving regions characterized by a marginal presence of hazelnut orchards. Despite this increasement, world production still relies on the cultivation of few varieties, most of which are particularly suitable to the environment where they have been selected. Therefore, it is necessary to develop new cultivars with high environmental plasticity capable of providing constant and high-quality productions in the new environments and under the climatic change conditions of traditional growing areas. Over the years, many molecular markers for genetic breeding programs have been developed and omics sciences also provided further information about the genetics of this species. These data could be of support to the application of new plant breeding techniques (NPBTs), which would allow the development of cultivars with the desired characteristics in a shorter time than traditional techniques. However, the application of these methodologies is subordinated to the development of effective regeneration protocols which, to date, have been set up exclusively for seed-derived explants. A further aspect to be exploited is represented by the possibility of cultivating hazelnut cells and tissues in vitro to produce secondary metabolites of therapeutic interest. This review aims to consolidate the state of the art on biotechnologies and in vitro culture techniques applied on this species, also describing the various studies that over time allowed the identification of genomic regions that control traits of interest.

A quantitative PCR assay for the detection and quantification of Septoria pistaciarum, the causal agent of pistachio leaf spot in Italy

Septoria leaf spot is one of the most widespread diseases affecting pistachio (Pistacia vera) in countries of the Mediterranean region. Septoria pistaciarum was recently confirmed as the causal agent of this disease in Italy. Currently, the detection of S. pistaciarum relies on isolation techniques. These require significant amounts of labor, and time for completion. Also, a reliable identification requires the sequencing of at least two housekeeping genes, in addition to the morphological observations. To accurately detect the presence and quantify S. pistaciarum in pistachio tissues, a molecular tool was necessary. We designed applicable primers that allow reliable amplification of the β-tubulin gene. The amplification of target DNA was highly efficient, with a 100% success rate, and the assay was able to detect as little as 100 fg/rxn of pure fungal DNA. When tested in artificial mixtures of plant and pathogen DNAs, the assay was able to detect the pathogen consistently at a limit of detection of 1 pg/rxn. The assay was also effective in identifying the pathogen in naturally infected samples, providing rapid detection in all symptomatic specimens. The resulting qPCR assay is an improved detection tool for accurate diagnosis of S. pistaciarum that can also contribute to better understand the population dynamics of the pathogen in the orchard.

Less is more: natural variation disrupting a miR172 gene at the di locus underlies the recessive double-flower trait in peach (P. persica L. Batsch)

BACKGROUND

With the domestication of ornamental plants, artificial selective pressure favored the propagation of mutations affecting flower shape, and double-flower varieties are now readily available for many species. In peach two distinct loci control the double-flower phenotype: the dominant Di2 locus, regulated by the deletion of the binding site for miR172 in the euAP2 PETALOSA gene Prupe.6G242400, and the recessive di locus, of which the underlying factor is still unknown.

RESULTS

Based on its genomic location a candidate gene approach was used to identify genetic variants in a diverse panel of ornamental peach accessions and uncovered three independent mutations in Prupe.2G237700, the gene encoding the transcript for microRNA miR172d: a ~5.0 Kb LTR transposable element and a ~1.2 Kb insertion both positioned upstream of the sequence encoding the pre-miR172d within the transcribed region of Prupe.2G237700, and a ~9.5 Kb deletion encompassing the whole gene sequence. qRT-PCR analysis confirmed that expression of pre-miR172d was abolished in di/di genotypes homozygous for the three variants.

CONCLUSIONS

Collectively, PETALOSA and the mutations in micro-RNA miR172d identified in this work provide a comprehensive collection of the genetic determinants at the base of the double-flower trait in the peach germplasms.

Complete genome assembly of the levan-positive strain PVFi1 of Pseudomonas savastanoi pv. savastanoi isolated from olive knots in Central Italy

Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot disease, is a fluorescent Gram-negative bacterium classified, according to the specific LOPAT profile, as Ib. However, during the 90s, a number of atypical non-fluorescent levan-positive strains of Pseudomonas savastanoi pv. savastanoi have been unexpectedly isolated from olive knots in Central Italy. Since its first report, several studies were conducted on this species variant, but its genome sequence has never been reported. The complete genome sequence and two additional plasmids of PVFi1, a representative strain, were here obtained using a hybrid sequencing approach with both Oxford Nanopore Technology and Illumina sequencing. A thorough genomic analysis unravelled several genetic features of this peculiar strain, showing a transposase insertion downstream a fragmented copy of the levansucrase gene. The same features were previously reported on levan-negative Pseudomonas savastanoi pv. savastanoi strains. In addition, a second copy of the levansucrase gene fully equipped for a gene expression and comparable to the levan-positive Pseudomonas savastanoi pv. glycinea, may explain the levan-positive test. This result provides a solid genetic demonstration that the bacterial species Pseudomonas savastanoi contains either levan-positive or levan-negative strains, providing insights for an update of the related LOPAT classification.

Role of methyl jasmonate and salicylic acid in kiwifruit plants further subjected to Psa infection: biochemical and genetic responses

The use of plant elicitors for controlling Pseudomonas syringae pv. actinidiae (Psa), the etiological agent of the kiwifruit bacterial canker (KBC), has been analysed in the past and, while salicylic acid (SA) seems to decrease disease susceptibility, methyl jasmonate (MJ) shows an opposite effect. However, the metabolic and genomic responses of Psa-infected plants following elicitation with these two compounds, as compared with non-elicited Psa-inoculated plants, are poorly understood, being the focus of this study. Micropropagated A. chinensis 'Hayward' plants were elicited with MJ or SA, and further inoculated with Psa. Fifteen days post-inoculation, Psa population in MJ-treated plants was increased by 7.4-fold, whereas SA elicitation led to decreased Psa colonization (0.5-fold), as compared with non-elicited inoculated plants. Additionally, elicitation with MJ or SA generally decreased polyphenols and lignin concentrations (by at least 20%) and increased total proteins (by at least 50%). MJ led to the upregulation of SOD, involved in plant antioxidant system, and reporter genes for the jasmonic acid (JA) (JIH and LOX1), abscisic acid (SnRK), SA (ICS1), and ethylene (ACAS1, ETR1 and SAM) pathways. Moreover, it increased ABA (40%) and decreased carotenoids (30%) concentrations. Contrastingly, comparing with non-elicited Psa-inoculated plants, SA application resulted in the downregulation of antioxidant system-related genes (SOD and APX) and of reporter genes for ethylene (ETR1) and JA (JIH and ETR1). This study contributes to the understanding of potential mechanisms involved in kiwifruit plant defences against Psa, highlighting the role of the JA, ABA and ethylene in plant susceptibility to the pathogen.

Draft Genome Sequence of a New Fusarium Isolate Belonging to Fusarium tricinctum Species Complex Collected From Hazelnut in Central Italy

In summer 2019, during a survey on the health status of a hazelnut orchard located in the Tuscia area (the province of Viterbo, Latium, Italy), nuts showing symptoms, such as brown-grayish spots at the bottom of the nuts progressing upward to the apex, and necrotic patches on the bracts and, sometimes, on the petioles, were found and collected for further studies. This syndrome is associated with the nut gray necrosis (NGN), whose main causal agent is Fusarium lateritium. Aiming to increase knowledge about this fungal pathogen, the whole-genome sequencing of a strain isolated from symptomatic hazelnut was performed using long Nanopore reads technology in combination with the higher precision of the Illumina reads, generating a high-quality genome assembly. The following phylogenetic and comparative genomics analysis suggested that this isolate is caused by the F. tricinctum species complex rather than F. lateritium one, as initially hypothesized. Thus, this study demonstrates that different Fusarium species can infect Corylus avellana producing the same symptomatology. In addition, it sheds light onto the genetic features of the pathogen in subject, clarifying facets about its biology, epidemiology, infection mechanisms, and host spectrum, with the future objective to develop specific and efficient control strategies.

Early Pathogen Recognition and Antioxidant System Activation Contributes to Actinidia arguta Tolerance Against Pseudomonas syringae Pathovars actinidiae and actinidifoliorum

Actinidia chinensis and A. arguta have distinct tolerances to Pseudomonas syringae pv. actinidiae (Psa), but the reasons underlying the inter-specific variation remain unclear. This study aimed to integrate the metabolic and molecular responses of these two kiwifruit species against the highly pathogenic Psa and the less pathogenic P. syringae pv. actinidifoliorum (Pfm) bacterial strains. Disease development was monitored weekly till 21 days post inoculation (dpi), analysing a broad number and variety of parameters including: colony forming units (CFU), foliar symptoms, total chlorophylls, lipid peroxidation, soluble polyphenols, lignin and defense-related gene expression. At the end of the experimental period A. chinensis inoculated with Psa presented the highest endophytic bacterial population, whereas A. arguta inoculated with Pfm showed the lowest values, also resulting in a lower extent of leaf symptoms. Metabolic responses to infection were also more pronounced in A. chinensis with decreased total chlorophylls (up to 55%) and increased lipid peroxidation (up to 53%), compared with non-inoculated plants. Moreover, at 14 dpi soluble polyphenols and lignin concentrations were significantly higher (112 and 26%, respectively) in Psa-inoculated plants than in controls, while in A. arguta no significant changes were observed in those metabolic responses, except for lignin concentration which was, in general, significantly higher in Psa-inoculated plants (by at least 22%), comparing with control and Pfm-inoculated plants. Genes encoding antioxidant enzymes (SOD, APX and CAT) were upregulated at an earlier stage in Psa-inoculated A. arguta than in A. chinensis. In contrast, genes related with phenylpropanoids (LOX1) and ethylene (SAM) pathways were downregulated in A. arguta, but upregulated in A. chinensis in the later phases of infection. Expression of Pto3, responsible for pathogen recognition, occurred 2 dpi in A. arguta, but only 14 dpi in A. chinensis. In conclusion, we found that A. arguta is more tolerant to Psa and Pfm infection than A. chinensis and its primary and secondary metabolism is less impacted. A. arguta higher tolerance seems to be related with early pathogen recognition, the activation of plant antioxidant system, and to the suppression of ET and JA pathways from an earlier moment after infection.

A new inclusive MLVA assay to investigate genetic variability of Xylella fastidiosa with a specific focus on the Apulian outbreak in Italy

The Olive Quick Decline Syndrome by Xylella fastidiosa subspecies pauca is among the most severe phytopathological emergencies nowadays. In few years, the outbreak devastated olive groves in Apulia (Italy), potentially endangering the entire Mediterranean basin. This research aimed to develop a multiple locus VNTR analysis assay, a molecular tool to differentiate between populations of the pathogen. It has already been successfully applied to different X. fastidiosa subspecies from various plant hosts. The previously published TR loci, together with a set of new design, have been tested in silico on the genome of the Apulian De Donno strain. The resulting selection of 37 TR loci was amplified on the genomic DNAs of the Apulian strains AND from representatives of X. fastidiosa subspecies, and directly on DNA extracted from infected plants. The assay clearly discerned among subspecies or even sequence types (ST), but also pointed out variants within the same ST so as to provide more detailed information on the dynamics and pathogen diffusion pathways. Its effective application even on total DNAs extracted from infected tissues of different host plants makes it particularly useful for large-scale screening of infection and for the strengthening of containment measures.

Genetic Diversity of Pseudomonas syringae pv. actinidiae Strains from Different Geographic Regions in China

Pseudomonas syringae pv. actinidiae causes kiwifruit bacterial canker, with severe infection of the kiwifruit plant resulting in heavy economic losses. Little is known regarding the biodiversity and genetic variation of populations of P. syringae pv. actinidiae in China. A collection of 269 strains of P. syringae pv. actinidiae was identified from 300 isolates obtained from eight sampling sites in five provinces in China. The profiles of 50 strains of P. syringae pv. actinidiae and one strain of P. syringae pv. actinidifoliorum were characterized by Rep-, insertion sequences 50, and randomly amplified polymorphic DNA polymerase chain reaction (PCR). Discriminant analysis of principal coordinates, principal component analysis, and hierarchical cluster analysis were used to analyze the combined fingerprints of the different PCR assays. The results revealed that all isolates belonged to the Psa3 group, that strains of P. syringae pv. actinidiae from China have broad genetic variability that was related to source geographic region, and that Chinese strains can be readily differentiated from strains from France but are very similar to those from Italy. Multilocus sequence typing of 24 representative isolates using the concatenated sequences of five housekeeping genes (cts, gapA, gyrB, pfk, and rpoD) demonstrated that strain Jzhy2 from China formed an independent clade compared with the other biovars, which possessed the hopH1 effector gene but lacked the hopA1 effector gene. A constellation analysis based on the presence or absence of the four loci coding for phytotoxins and a cluster analysis based on the 11 effector genes showed that strains from China formed two distinct clades. All of the strains, including K3 isolated in 1997 from Jeju, Korea, lacked the cfl gene coding for coronatine. In contrast, the tox-argK gene cluster coding for phaseolotoxin was detected in K3 and in the biovar 1 strains (K3, Kw30, and Psa92), and produced a false-positive amplicon for the hopAM1-like gene in this study. To date, only one biovar (biovar 3) is represented by the strains of P. syringae pv. actinidiae from China, despite China being the center of origin for kiwifruit.

Sustainable control strategies for plant protection and food packaging sectors by natural substances and novel nanotechnological approaches

An overview is provided of the current technological strategies (also at the nanoscale level) recently involved in plant and/or food protection. In addition, the potential use of natural and sustainable substances, instead of traditional synthesized molecules or chemical-based compounds, is addressed both with respect to packaging systems and novel pesticide formulations. In this context, nanotechnological approaches represent promising strategies for the entire agriculture industry chain, from the field to consumers. Traditional plant protection strategies are often insufficient and the application of chemical-based pesticides has negative effects on animals, humans and the environment. Novel greener tools could represent efficient alternatives for the management of plant diseases using promising strategies; the use of nanotechnologies allows the promotion of the more efficient assembly and subsequent release of environmentally sustainable active principles, limiting the use of chemicals in terms of economic losses. At the same time, new sustainable, antimicrobial and antioxidant systems have been rapidly promoted and investigated in the food packaging sector as a valid eco-friendly possibility for improving the safety and quality of food products and reducing and/or limiting the environmental impact with respect to traditional materials. Together, the scientific community and the growing interest of consumers have promoted the development of new edible and eco-friendly packaging that reduces waste and any environmental impact. In this context, the aim is to provide evidence of the usefulness of strategies aiming to limit agrochemicals, as well as the potential of nanomaterials, in sustainable plant and food protection for agriculture management and the packaging sector. © 2018 Society of Chemical Industry.

Tailored-BODIPY/Amphiphilic Cyclodextrin Nanoassemblies with PDT Effectiveness

Amphiphilic cyclodextrins (aCDs) are an intriguing class of carrier systems which, recently, have been proposed to deliver porphyrinoids and anticancer drugs or combined dose of both for dual therapeutic applications. The design of nanoassemblies based on aCD and photosensitizers (PSs) aims to preserve the photodynamic therapy (PDT) efficacy of PS, reducing the tendency of PS to self-aggregate, without affecting the quantum yield of singlet oxygen (¹O₂) production, and, not less importantly, minimizing dark toxicity and reducing photosensitization effects. With this idea in mind, in this paper, we focus on nanoassemblies between a non-ionic aCD (SC6OH) and halo-alkyl tailored iodinated boron-dipyrromethenes (BODIPY) dye, a class of molecules which recently have been successfully proposed as a stimulating alternative to porphyrinoids for their high photodynamic efficacy. Nanoassemblies of BODIPY/aCD (BL01I@SC6OH) were prepared in different aqueous media by evaporation of mixed organic film of aCD and BODIPY, hydration, and sonication. The nanostructures were characterized, measuring their hydrodynamic diameter and ξ-potential and also evaluating their time-stability in biological relevant media. Taking advantage of emissive properties of the not-iodinated BODIPY analogue (BL01), nanoassemblies based on aCD and BL01 were investigated as model system to get insight on entanglement of BODIPY in the amphiphile in aqueous dispersion, pointing out that BODIPY is well-entrapped in monomeric form (τ ≅ 6.5 ns) within the colloidal carriers. Also morphology and fluorescence emission properties were elucidated after casting the solution on glass. BL01@SC6OH is easily detectable in cytoplasm of HCT116 cell lines, evidencing the remarkable intracellular penetration of this nanoassembly similar to free BODIPY. On the same cell lines, the photodynamically active assembly BL01I/aCD shows toxicity upon irradiation. Despite the fact that free BL01I is more PDT active than its assembly, aCD can modulate the cell uptake of BODIPY, pointing out the potential of this system for in vivo PDT application.

Pomological Traits, Sensory Profile and Nutraceutical Properties of Nine Cultivars of Loquat (Eriobotrya japonica Lindl.) Fruits Grown in Mediterranean Area

In this paper the diversity of fruit quality within nine loquat cultivars, including five international affirmed cultivars (Algerie, Golden Nugget, Peluche, Bueno, El Buenet) and four local cultivars (Sanfilippara, Nespolone di Trabia, BRT20 and Claudia), were investigated in order to discriminate the variation in pomological characteristics, sensory profile, and antioxidant properties. Finally, to evaluate potential bioactivity, antiproliferative activity of hydrophilic extracts from loquat fruits was assessed, at dietary relevant concentrations, against three human epithelial cell lines. Even though the international cultivars confirmed an appropriate level of commercial qualities in association to high levels in antioxidant compounds, the local cultivars revealed the best performances in a wide range of chemical-physical and sensory characteristics. Concerning bioactivity, our results indicate that hydrophilic extracts from all tested cultivars showed concentration-dependent antiproliferative activity with a significant variability of effects between different cell lines and between different cultivars. HeLa cells, the most sensitive and hydrophilic extracts from Peluche, showed the highest inhibitory effect followed by Nespolone di Trabia and Claudia. The results of this trial provide useful information on the pomological traits and the not yet known specific nutritional and functional properties of loquat fruits. Our data, besides helping to promote specific local cultivars, could serve to establish a database that will permit to improve the utilization of specific genetic resources in breeding programs.

Nanospheres based on PLGA/amphiphilic cyclodextrin assemblies as potential enhancers of Methylene Blue neuroprotective effect

Nanospheres of amphiphilic cyclodextrin and PLGA entrapping Methylene Blue are proposed as potential enhancers of drug neuroprotective effect on neuroblastoma cells.

Development of a Multiple Loci Variable Number of Tandem Repeats Analysis (MLVA) to Unravel the Intra-Pathovar Structure of Pseudomonas syringae pv. actinidiae Populations Worldwide

The bacterial canker of kiwifruit by Pseudomonas syringae pv. actinidiae is an emblematic example of a catastrophic disease of fruit crops. In 2008 a new, extremely virulent form of the pathogen emerged and rapidly devastated many Actinidia spp. orchards all over the world. In order to understand differences in populations within this pathovar and to elucidate their diffusion and movements on world scale, it is necessary to be able to quickly and on a routine basis compare new isolates with previous records. In this report a worldwide collection of 142 strains was analyzed by MLVA, chosen as investigative technique for its efficacy, reproducibility, simplicity and low cost. A panel of 13 Variable Number of Tandem Repeats (VNTR) loci was identified and used to describe the pathogen population. The MLVA clustering is highly congruent with the population structure as previously established by other molecular approaches including whole genome sequencing and correlates with geographic origin, time of isolation and virulence. For convenience, we divided the VNTR loci in two panels. Panel 1 assay, using six loci, recognizes 23 different haplotypes, clustered into ten complexes with highest congruence with previous classifications. Panel 2, with seven VNTR loci, provides discriminatory power. Using the total set of 13 VNTR loci, 58 haplotypes can be distinguished. The recent hypervirulent type shows very limited diversity and includes, beside the strains from Europe, New Zealand and Chile, a few strains from Shaanxi, China. A broad genetic variability is observed in China, but different types are also retrievable in Japan and Korea. The low virulent strains cluster together and are very different from the other MLVA genotypes. Data were used to generate a public database in MLVAbank. MLVA represents a very promising first-line assay for large-scale routine genotyping, prior to whole genome sequencing of only the most relevant samples.

Engineering of carbon based nanomaterials by ring-opening reactions of a reactive azlactone graphene platform

A reactive azlactone-based graphene nanoplatform was successfully synthesized by the ligation of azido-azlactone with alkyne-terminated graphene via Cu(I)-catalyzed cycloaddition. The reactive azlactone rings, grafted on graphene sheets, were subjected to highly efficient ring-opening reactions with functionalized primary amine derivatives incorporating an aminosilane coupling agent or a biological fragment.

A Multiplex PCR Assay for Detection of Pseudomonas syringae pv. actinidiae and Differentiation of Populations with Different Geographic Origin

Pseudomonas syringae pv. actinidiae is responsible for severe outbreaks of bacterial canker of kiwifruit currently occurring around the world. Although molecular detection methods have been reported, none provide complete selectivity for this pathovar or discriminate among pathogen haplotypes. Therefore, a new multiplex polymerase chain reaction (PCR) assay was developed and validated. The assay was tested on 32 P. syringae pv. actinidiae isolates and 15 non-P. syringae pv. actinidiae strains and correctly assigned P. syringae pv. actinidiae strains to three different haplotypes: a Japanese/Korean group, a European group, and a Chinese group. Two P. syringae pv. actinidiae isolates from New Zealand were found to belong to the Chinese group whereas two other isolates from New Zealand, which were isolated from kiwifruit plants but which do not cause bacterial canker, tested negative. The described PCR assays has a limit of detection of approximately 5 to 50 pg of purified DNA or of 5 × 10² bacteria/PCR and were shown to work with both artificially and naturally infected plant tissues. Thus, the described method represents a suitable tool for detection of P. syringae pv. actinidiae and haplotype attribution, in particular, when testing a high number of samples during surveillance and prevention activities.

Predicting the potential global distribution of Pseudomonas syringae pv actinidiae (Psa)

The increasing spread of kiwifruit bacterial canker caused by Pseudomonas syringae pv actinidiae (Psa) prompted a modelling effort to assess the global and local potential risk of this species The current potential distribution of Psa was modelled with two wellused models (CLIMEX and MaxEnt) based on available presence records and environmental data Most discrepancies in model projections occurred for New Zealand data that was used for validation Model projections can provide information to alert decisionmakers in kiwifruitgrowing regions to prepare for possible incursions of Psa However in this study because model findings did not agree on the New Zealand validation data more research is necessary to achieve greater confidence on projections for novel areas Despite that result this study provides useful information for some kiwifruit growing countries that have not yet been affected by Psa such as USA Iran Greece Belgium Denmark and especially South Africa where commercial kiwifruit orchards have been planted recently

Bacterial canker on kiwifruit in Italy: anatomical changes in the wood and in the primary infection sites

The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae is a severe threat to kiwifruit production worldwide. Many aspects of P. syringae pv. actinidiae biology and epidemiology still require in-depth investigation. The infection by and spread of P. syringae pv. actinidiae in xylem and phloem was investigated by carrying out artificial inoculation experiments with histological and dendrochronological analyses of naturally diseased plants in Italy. We found that the bacterium can infect host plants by entering natural openings and lesions. In naturally infected kiwifruit plants, P. syringae pv. actinidiae is present in the lenticels as well as in the dead phloem tissue beneath the lenticels, surrounded by a lesion in the periderm which appears to indicate the importance of lenticels to kiwifruit infection. Biofilm formation was observed outside and inside plants. In cases of advanced stages of P. syringae pv. actinidiae infection, neuroses of the phloem occur, which are followed by cambial dieback and most likely by infection of the xylem. Anatomical changes in wood such as reduced ring width, a drastic reduction in vessel size, and the presence of tyloses were observed within several infected sites. In the field, these changes occur only a year after the first leaf symptoms are observed suggesting a significant time lapse between primary and secondary symptoms. It was possible to study the temporal development of P. syringae pv. actinidiae-induced cambial dieback by applying dendrochronology methods which revealed that cambial dieback occurs only during the growing season.

Pseudomonas syringae pv. actinidiae (PSA) isolates from recent bacterial canker of kiwifruit outbreaks belong to the same genetic lineage

Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis) caused by Pseudomonas syringae pv. actinidiae (PSA). The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form of the disease broke out in Italy in 2008 and in additional countries in 2010 and 2011 threatening the viability of the global kiwi fruit industry. To start investigating the source and routes of international transmission of PSA, genomes of strains from China (the country of origin of the genus Actinidia), Japan, Korea, Italy and Portugal have been sequenced. Strains from China, Italy, and Portugal have been found to belong to the same clonal lineage with only 6 single nucleotide polymorphisms (SNPs) in 3,453,192 bp and one genomic island distinguishing the Chinese strains from the European strains. Not more than two SNPs distinguish each of the Italian and Portuguese strains from each other. The Japanese and Korean strains belong to a separate genetic lineage as previously reported. Analysis of additional European isolates and of New Zealand isolates exploiting genome-derived markers showed that these strains belong to the same lineage as the Italian and Chinese strains. Interestingly, the analyzed New Zealand strains are identical to European strains at the tested SNP loci but test positive for the genomic island present in the sequenced Chinese strains and negative for the genomic island present in the European strains. Results are interpreted in regard to the possible direction of movement of the pathogen between countries and suggest a possible Chinese origin of the European and New Zealand outbreaks.

Physico-chemical characterization of an amphiphilic cyclodextrin/genistein complex

Specific recognition of cell-targeting systems as host-carriers modified with receptor targeting groups, is a major ambition in the application of supramolecular science to medicine and life science. Genistein (Gen), an isoflavone belonging to the class of phytoestrogens, is of great interest because it has been considered as potential remedy for many kinds of disease. In this work, genistein in aqueous medium and in the presence of an host nanocarrier as amphiphilic cyclodextrin (CyD) modified in the upper rim with oligoethylene hydroxyl groups [(2-oligo(ethyleneoxide)-6-hexylthio)-beta-CyD, SC6OH] at 1:1 molar ratio, has been firstly investigated by UV-vis measurements coupled with circular dichroism data, in order to characterize the drug/macrocycle binding affinity through the formation of the complex. Furthermore, FTIR-ATR technique has been used to detect the complex formation in solid phase and to characterize the functional groups responsible of the solid Gen/SC6OH complex stability. The infrared absorbance spectra of the complex, collected in a wide range of wavenumber and around the physiological temperature, have been analysed and compared with the spectra of the pure compounds and their physical mixture. By monitoring the most significant changes in the shape and position of the absorbance bands of the Gen functional groups, we showed that the formation and/or modification of polar bonds play the main role in the interaction of the drug with the amphiphilic CyD. From the results, Gen is shown to be entangled in SC6OH nanoaggregates, establishing hydrogen bonding with the hydrophilic PEG chains.

Outbreak of Bacterial Blossom Blight Caused by Pseudomonas viridiflava on Actinidia chinensis Kiwifruit Plants in Italy

During the springs from 2006 to 2008, a new disease was observed on 4- to 5-year-old Actinidia chinensis (cv. Jin Tao) trees in different commercial kiwifruit-production areas in northern Italy (Lombardy). Initially, disease occurrence was sporadic but later became widespread. Symptoms on flowers appeared as a dark brown rot of anthers, filaments, sepals, and whole buds. Blossoms abscised prematurely from buds. Symptoms appeared as confluent brown spots often present on rolled margins. Bacteria were isolated from symptomatic tissue on nutrient agar medium supplemented with 5% sucrose. The isolated bacteria were aerobic; produced a diffusible fluorescent pigment on King's B medium; levan, oxidase, and arginine dihydrydrolase negative, and catalase positive; rotted potato tuber tissue; caused a hypersensitive response on tobacco; and failed to reduce nitrate or utilize sucrose and were ice nuclease-positive at -5°C, suggesting the organism was P. viridiflava (1,3). Inoculation of 2-year-old A. chinensis cv. Jin Tao plants were carried out in the greenhouse under controlled environmental conditions (15 to 27°C, night/day; relative humidity up to 70%) by spraying five plants in bloom with a suspension (1 × 10⁸ CFU/ml) of isolated bacteria with a hand-held sprayer that produced large spray droplets. Symptoms, similar to those in nature, were observed on flowers and buds 3 to 5 days after inoculation and on leaves after 7 to 10 days. Using the same tests described above with the original strains, the strains that were isolated from symptomatic tissue were identified as Pseudomonas viridiflava. Seven bacterial strains (PV508-PV1108) were identified by sequencing 1,481 bp of their 16S rDNA region (2) and using BlastN (4) for the most similar sequences in the INSD (GenBank, EMBL, and DDBJ). Our sequences shared 99.53% (1,474 of 1,481 bp) to 99.9% (1480 of 1,481 bp) identity with the analogous sequences of P. viridiflava available in the database. To our knowledge, this is the first report of an outbreak of blossom blight caused by P. viridiflava on A. chinensis cv. Jin Tao kiwifruit plants in Italy. Previously, it was reported on A. deliciosa cv. Hayward (3). Because of the risk of bacterial contamination among the different cultivars of kiwifruit, further investigation and development of control measures are in progress. References: (1) R. A. Lelliott and D. E. Stead. Methods for the Diagnosis of Bacterial Diseases of Plants. Blackwell Scientific, Oxford, UK, 1987. (2) E. R. B. Moore et al. Syst. Appl. Microbiol. 19:478, 1996. (3) L. Varvaro et al. Inf. Fitopatol. 6:49, 1990. (4) Z. Zhang et al. J. Comput. Biol. 7(1-2):203, 2000.

The enhancement of isoflavones water solubility by complexation with modified cyclodextrins: a spectroscopic investigation with implications in the pharmaceutical analysis

The improvement of isoflavones bioavailability by complexation with chemically modified cyclodextrins (CyDs) has been exploited to analyse the drug/macrocycle binding affinity by a conventional method with new useful measures. Genistein (Gen) and daidzein (Daidz) were investigated in aqueous medium and in presence an amount of (2-hydroxypropyl)-beta-cyclodextrin (HP-beta-CyD) at different host/guest molar ratios. The solubility in pure water, approximately 3 x 10(-6)M for Gen and approximately 10 x 10(-6)M for Daidz, was obtained by distributing the of guest molecule between water and the organic solvent. The stoichiometric ratios and stability constants describing the extent of formation of the complexes have been determined by phase-solubility UV-vis measurements and confirmed by circular dichroism data. These results have implications in the determination of the carrier's capacity for the complexation of the drug in water solution.

New cyclodextrin derivatives as chiral selectors in capillary electrophoresis

The separation of three pairs of enantiomeric herbicides has been successfully achieved by capillary electrophoresis at two different pH values in the presence of cyclodextrin derivatives previously synthesized in our laboratory. Two of these derivatives constitute a new class of receptor, the hemispherodextrins, in which a trehalose capping moiety is bonded to beta-cyclodextrin. Because of their peculiar structure hemispherodextrins have very promising characteristics and the low receptor concentration required to achieve separation deserves particular interest.