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Characterization of Burkholderia gladioli strains causal agents of saffron (Crocus sativus L.) bacterial rot
No full textBurkholderia gladioli is the causal agent of a bacterial disease
recently reported in saffron (Crocus sativus L.) grown in central
Sardinia (Italy). The symptoms were rot of emerging flowers and
shoots, and spots on leaves. In the last two years the disease has
been particularly harmful, reducing flowering by some 80%. Isolations
on nutrient glucose agar from symptomatic plants produced
two types of colony. The first type (ten isolates) was round,
wrinkled, and yellowish. The second type (fifteen isolates) was
round, smooth and colourless. In pathogenicity tests, the twenty
five isolates reproduced symptoms on saffron plants, while only
the first type of isolate was pathogenic on gladiolus leaves. The
twenty five isolates were analyzed with the computerised BIOLOG
system, conventional tests and genomic tests such as PCR
and PCR-RFLP. BIOLOG, conventional tests and PCR using
LP1 and LP4 primers, identified all isolates as Burkholderia gladioli.
PCR-RFLP analysis using three restriction enzymes (AluI,
DdeI and BssKI), identified only ten of the isolates (nine wrinkled
and one smooth) as B. gladioli pv. gladioli. Our evidence indicates
that other B. gladioli forms are also involved in this bacterial rot
of saffron, and further studies are under way to verify this
Attività di prodotti eco-compatibili per il controllo di agenti del “deperimento” del nocciolo in Sardegna.
No full textAl fine di contenere i danni causati da Pseudomonas syringae pv. coryli (Psc), P. s. pv. syringae (Pss) e Xanthomonas arboricola pv. corylina (Xac), agenti rispettivamente della “moria dei rametti”, dell’“avvizzimento dei rametti e delle branche” e del “bacterial blight” su nocciolo in Sardegna, sono stati saggiati nove oli essenziali (Artemisia arborescens, Bupleurum fructicosum, Foeniculum vulgare, Lavandula stoechas, Mentha pulegium, Myrtus communis, Rosmarinus officinalis, Salvia desoleana e Thymus capitatus) estratti da piante coltivate in Sardegna e cinque ceppi antagonisti isolati da piante di timo (DPPSS T1, DPPSS T2, DPPSS T3, DPPSS T4 e DPPSS T5). Gli antagonisti erano Gram positivi, formavano endospore, negativi all’ossidasi e in base ai profili nutrizionali ottenuti con il sistema Biolog sono stati ascritti a Bacillus amyloliquefaciens.
Preliminarmente in vitro è stata determinata, con il metodo della diffusione in agar, l’attività antibatterica di oli essenziali e antagonisti nei confronti di quattro ceppi di Pss, due di Psc e due di Xac. Per gli oli più efficaci (Finocchio, Menta, Mirto, Rosmarino e Timo), è stata determinata, in brodo nutritivo, la concentrazione minima inibitoria. Essa era di 600 ppm per gli oli di Finocchio, Menta e Mirto; di 400 ppm per l’olio di Timo; per il Rosmarino era superiore a 800 ppm. Fra i ceppi antagonisti, l’efficacia maggiore è stata mostrata dagli isolati DPPSS T2, DPPSS T3.
I quattro oli essenziali più efficaci (Finocchio, Menta, Mirto e Timo) sono stati saggiati per la fitotossicità su piantine di nocciolo, pomodoro e frutti di limone. Su foglie di nocciolo sono risultati fitotossici l’olio essenziale di Finocchio ed in minor misura quello di Menta; quello di Timo è risultato fitotossico sulle piantine di pomodoro. Gli antagonisti DPPSS T2 e DPPSS T3 saggiati per la reazione di ipersensibilità su tabacco e la patogenicità su piantine di nocciolo, pomodoro e frutti di limone sono risultati negativi.
La capacità di controllo di oli e antagonisti degli otto ceppi batterici (Pss, Psc e Xac) è stata valutata in infezioni sperimentali su piantine di nocciolo allevate in vaso e, per i ceppi di Pss, anche su frutti di limone. I risultati (osservazioni e isolamenti su mezzi idonei) hanno indicato che oli e antagonisti irrorati prima delle inoculazioni erano in grado di prevenire le infezioni.Activity of essential oils and bacterial isolates to control bacterial strains causal agents of hazelnut decline in Sardinia
In order to control the damage caused by Pseudomonas syringae pv. coryli (Psc), P. s. pv. syringae (Pss) and Xanthomonas arboricola pv. corylina (Xac), causal agents respectively of “twig dieback”, “twig and branch wilting” and “bacterial blight” of hazelnut in Sardinia, nine essential oils extracted from plants of Artemisia arborescens, Bupleurum fructicosum, Foeniculum vulgare, Lavandula stoechas, Mentha pulegium, Myrtus communis, Rosmarinus officinalis, Salvia desoleana and Thymus capitatus grown in Sardinia, and five bacterial antagonistic isolated from thymus plants (DPPSS T1, DPPSS T2, DPPSS T3, DPPSS T4 and DPPSS T5) were tested. Antagonistic isolates were positive for Gram reaction and endospore formation, negative for oxidase; Biolog system identified our isolates as Bacillus amyloliquefaciens.
In a preliminary trial essential oils and antagonistic bacteria were screened in vitro by the diffusion agar method for antibacterial activity against four pathovars of Pss, two of Psc and two of Xac. In order to determine the minimum inhibitory concentration, the more efficacious ones (Fennel, Mint, Myrtle, Rosemary and Thyme) were tested in nutrient broth. For Fennel, Mint and Myrtle oils the minimum inhibitory concentration was 600 ppm, for Thyme was 400 ppm, while, for Rosemary oil, the minimum inhibithory concentration was above 800 ppm. Among the antagonistic bacteria, DPPSS T 2 and DPPSS T 3 were the most efficacious.
Fennel, Mint, Myrtle and Thyme essential oils were tested for toxicity on hazelnut and tomato plants and lemon fruits. Fennel essential oil was more toxic than Mint on hazelnut leaves; while Thyme essential oil was toxic on tomato plants only. Antagonistic bacteria DPPSS T 2 and DPPSS T 3 were not able to elicit the hypersensitivity reaction on tobacco leaves and were not pathogenic on hazelnut and tomato plants and lemon fruits.
The effectiveness of essential oils and antagonistic bacteria to control bacterial pathogens (Pss, Psc and Xac) were evaluated on hazelnut and tomato plants and for Pss strains also on lemon fruits experimentally infected. The results (observations and isolations on suitable media) showed that essential oils and antagonistic bacteria were able to prevent infections when plants and fruits were treated before inoculation
Beauveria bassiana strain ATCC 74040 interferes with oviposition behavior of Mediterranean fruit fly
No full textCaratterizzazione di popolazioni di Pseudomonas syringae agenti dell’ “avvizzimento” di rami e branche su nocciolo in Sardegna
No full textCaratterizzazione di isolati di Pseudomonas syringae agenti dell’avvizzimento del nocciolo in Sardegna
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The acylation of an acyl complex resulting in a labile OCO tridentate ligand
No full textreaction of propionic anhydride with [fac-Ru(C(O)Et)-(CO)2(H2O) 3] [CF3SO3] produces a new propylidin dipropionato group, which behaves as a tridentate ligand giving the neutral complex Ru{CEt(OC(O)Et)2}(CO) 2(CF3SO3)
Saffron (Crocus sativus L.) diseases in Italy.
No full textSurveys carried out in different Italian saffron-growing areas
showed the presence of some fungal and bacterial diseases. Fusarium
oxysporum f. sp. gladioli, a fungus transmitted through infected
corms, was the major responsible of severe yield losses, especially
in central Italy and, recently, also in Sardinia (Medio
Campidano). Primary symptoms occurred during flowering.
They included basal stem rot, yellowing and wilting of the shoots
and corm rot. The rapid spread of the disease is caused by movement
of contaminated and/or infected corms. The Italian fungus
isolates from saffron did not differ by those obtained from gladiolus
or saffron grown in Spain as shown by VCs groups studies.
Macrophomina phaseolina was found in Sardinia. The fungus was
transmitted by infected corms and caused wilting of plants and
charcoal rot of corms. Penicillium spp. and Stromatinia gladioli
were also found in/on the corms at the time of transplanting. Recent
investigations carried out in Sardinia showed that Burkolderia
sp. and Pseudomonas spp. are the causal agents of a disease
characterized by rotting of the leaves, flowers and corms. Smooth
and winkled colonies were isolated from plants and corms. Bacterial
isolates were characterized by pathogenicity, phenotypic and
PCR analysis. Most of the isolates were identified as Burkholderia
gladioli and some as fluorescent pseudomonads. FLP analysis are
under way to characterize the pathovar of the B. gladioli isolates.
Other fungi that were recorded many years ago, such as Rhizoctonia
spp. and Phoma crocophila, were not found
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