Studi epidemiologici su Pseudomonas syringae pv.actinidiae agente causale del cancro batterico in actinidia

Il cancro batterico dell’actinidia causato da Pseudomonas syringae pv.actinidiae (Psa) suscita grande interesse a livello globale a partire dal 2008. La malattia è comparsa in Giappone e in due anni ha avuto una diffusione epidemica in tutte le aree di coltivazione mondiale di actinidia. Gravi perdite economiche hanno attirato l’attenzione internazionale su questa problematica e grandi sforzi sono stati rivolti allo studio di questo patosistema ancora poco conosciuto. E’ emerso infatti che il patogeno può rimanere in fase latente per lunghi periodi senza causare sintomi caratteristici nelle piante infette, e che dalla comparsa dei sintomi la pianta muore nell’arco di un paio d’anni. Il monitoraggio ed il controllo della situazione è perciò di fondamentale importanza ed è ancora più importante prevenire la comparsa di nuovi focolai di infezione. A questo proposito sarebbe opportuno l’impiego di materiale vegetale di propagazione non infetto, ma in molti casi questo diventa difficile, dal momento che il materiale impiegato è generalmente quello asintomatico, non analizzato precedentemente per la presenza del patogeno. Negli ultimi anni sono state perciò messe a punto molte tecniche molecolari per l’identificazione di Psa direttamente da materiale vegetale. L’obiettivo di questo lavoro è stato quello di studiare l’epidemiologia di Psa in piante adulte infette e di verificare l’efficacia di metodi di diagnosi precoce per prevenire la malattia. A tale scopo il lavoro sperimentale è stato suddiviso in diverse fasi: i) studio della localizzazione, traslocazione e sopravvivenza di Psa nelle piante, a seguito di inoculazione in piante adulte di actinidia di ceppi marcati Psa::gfp; ii) studio della capacità di Psa di essere mantenuto in germogli di actinidia attraverso sette generazioni di micropropagazione dopo l’inoculazione delle piante madri con lo stesso ceppo marcato Psa::gfp; iii) studio ed applicazioni di un nuovo metodo di diagnosi precoce di Psa basato sull’analisi molecolare del “pianto”.

Dissecting the Heat-Stress Tolerance QTLome in Durum Wheat

Heat stress negatively affects wheat performance during its entire cycle, particularly during the reproductive stage. In view of the climate change and the prediction of a continued increase in temperature in the new future, it is urgent to concentrate efforts to discover novel genetic sources able to improve the resilience of wheat to heat stress. In this direction, this study addressed two different experiments in durum wheat to identify novel QTLs suitable to be applied in marker-assisted selection for heat tolerance. Chlorophyll fluorescence (ChlF) is a valuable indicator of plant response to environmental changes allowing a detailed assessment of PSII activity in view of its non-invasive measurement and high-throughput phenotyping. In the first study (Chapter 2), the Light-Induced Fluorescence Transient (LIFT) method was used to access ChlF data to map QTLs for ChlF-related traits during the vegetative growth stage in durum wheat under heat stress condition. Our results provide evidence that LIFT consistently measures ChlF at the level of high-throughput phenotyping combined with high accuracy which is required for Genome-Wide Association Study (GWAS) aimed at identifying genomic regions affecting PSII activity. The 50 QTLs identified for ChlF-related traits under heat stress mostly clustered into five chromosomes hotspots unrelated to phenology, a feature that makes these QTLs a valuable asset for marker-assisted breeding programs across different latitudes. In the second study (Chapter 3), a set of 183 accessions suitable for GWAS, was exposed to optimal and high temperature during two crop seasons under field conditions. Important agronomic traits were evaluated in order to identify valuable QTLs for GY and its components. The GWAS analysis identified several QTLs in the single years as well as in the joint analysis. From the total QTLs identified, 13 QTL clusters can be highlighted to be affecting heat tolerance across different years and/or different traits.

Efficient wireless coverage of in-building environments with low electromagnetic impact

The city of tomorrow is a major integrating stake, which crosses a set of major broad spectrum domains. One of these areas is the instrumentation of this city and the ubiquity of the exchange of data, which will give the pulse of this city (sensors) and its breathing in a hyper-connected world within indoor and outdoor dense areas (data exchange, 5G and 6G). Within this context, the proposed doctorate project has the objective to realize cost- and energy- effective, short-range communication systems for the capillary wireless coverage of in-door environments with low electromagnetic impact and for highly dense outdoor networks. The result will be reached through the combined use of: 1) Radio over Fiber (RoF) Technology, to bring the Radio Frequency (RF) signal to the different areas to be covered. 2) Beamforming antennas to send in real time the RF power just in the direction(s) where it is really necessary.

Retrospective assessment of fracture risk through opportunistic radiological screening in a large modern cohort of liver transplant recipients

Objective: Liver transplantation has been associated with a high prevalence of osteoporosis, although most data rely on single-center studies with limited sample size, with most of them dating back to late 1990s and early 2000s. The present thesis aims to assess the prevalence of fragility fractures and contributing factors in a large modern cohort of liver transplant recipients managed in a referral Italian Liver Transplant Center. Design and Methods: Paper and electronic medical records of 429 consecutive patients receiving liver transplantation from 1/1/2010 to 31/12/2015 were reviewed, and 366 patients were selected. Clinically obtained electronic radiological images within 6 months from the date of liver transplant surgery, such as lateral views of spine X-rays or CT abdominal scans, were opportunistically reviewed in a blinded fashion to screen for morphometric vertebral fractures. Clinical fragility fractures reported in the medical records, along with information on etiology of cirrhosis and biochemistries at the time of liver surgery were also recorded. Results: Prevalence of fragility fractures in the whole cohort was 155/366 (42.3%), with no significant differences between sexes. Of patients with fractures, most sustained vertebral fractures (145/155, 93.5%), the majority of which were mild or moderate wedges. Multiple vertebral fractures were common (41.3%). Fracture rates were similar across different etiologies of cirrhosis and were also comparable in patients with diabetes or exposed to glucocorticoids. Kidney function was significantly worse in women with fractures. Independent of age, sex, alcohol use, eGFR, etiology of liver disease, lower BMI was the only independent risk factor for fractures (adjusted OR 1,058, 95%CI 1,001-1,118, P=0.046) in this study population. Conclusions: A considerable fracture burden was shown in a large and modern cohort of liver transplant recipients. Given the remarkably high prevalence of fractures, a metabolic bone disease screening should be implemented in every patient awaiting liver transplantation.