http://openpub.fmach.it:80 The OpenPub digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2013-06-20T00:58:33Z http://hdl.handle.net/10449/22104 Title: Dissecting the tripartite interaction between Vitis vinifera, Plasmopara viticola and the biocontrol agent Trichoderma harzianum T39 Authors: PALMIERI, MARIA CRISTINA; PERAZZOLLI, MICHELE; PERTOT, ILARIA Abstract: The biocontrol agent Trichoderma harzianum T39 reduce downy mildew severity on susceptible grapevines by inducing plant resistance. By cytological and molecular approaches, we aimed to identify mechanisms responsible of the grapevine self-defence. T39 resulted to induce a direct modulation of the receptor and recognition plant-machinery and activates a priming state for enhanced expression of stress-related proteins after pathogen inoculation. Citation: Palmieri, M., Perazzolli, M., Matafora, V., Bachi, A., & Pertot, I. (2013). Dissecting the tripartite interaction between Vitis vinifera, Plasmopara viticola and the biocontrol agent Trichoderma harzianum T39. IOBC/WPRS bulletin, 86, 129-131. 2012-12-31T23:00:00Z http://hdl.handle.net/10449/22099 Title: A rapid test to detect exo-chitinase activity for soil microorganisms using 4-methylumbelliferyl-N-acetyl-B-D-glucosaminide Authors: PELLEGRINI, ALBERTO; PERTOT, ILARIA; ASENSIO HERRERO, NOEMI Abstract: Fungi and bacteria represent important functional components of terrestrial ecosystems, they are essential for a variety of bio-geochemical processes such as C, N, S and Fe cycles (Murphy et al. 2007), and some of them represent powerful tools for biological crop protection. There are microorganisms that have the ability of controlling the growth of some plant pathogens by producing different substances that inhibit their development (Dennis and Webster 1974). Several of these substances are enzymes such as chitinases, proteases, peroxidases, etc. In this study we propose a rapid and economical method to evaluate exo-chitinase activity using 4-methylumbelliferyl-N-acetyl-β-D-glucosaminide (4-MUF.GlcNAc). This method was tested in vitro for the evaluation of the enzyme activity in a system composed of a soil pathogen (Armillaria mellea) and 12 different soil microorganisms. Citation: Pellegrini, A., Herreo, N., & Pertot, I. (2013). A rapid test to detect exo-chitinase activity for soil microorganisms using 4-methylumbelliferyl-N-acetyl-B-D-glucosaminide. IOBC/WPRS bulletin, 86, 319-320. 2012-12-31T23:00:00Z http://hdl.handle.net/10449/22068 Title: Deer density drives tick infestation pattern on rodents and TBE hazard: empirical and theoretical investigations Authors: BOLZONI, LUCA; CAGNACCI, FRANCESCA; ROSÀ, ROBERTO; RIZZOLI, ANNAPAOLA Abstract: Tick-borne encephalitis (TBE) is an emerging zoonotic disease reported in several European and Asiatic countries with complex transmission routes that involve various host species. Understanding and quantifying the contribution of the different hosts involved in the TBE virus (TBEV) cycle is crucial to estimating the threshold conditions for virus emergence and spread. Some hosts, such as rodents, act as both feeding host for ticks and reservoir of the infection. Other species, such as deer, provide important sources of blood for feeding ticks, but they do not support TBEV transmission, acting instead as dead-end (i.e. incompetent) hosts. The aim of this study was to estimate the contribution of the main ungulate tick hosts to the pattern of tick infestation on rodents, and to TBEV occurrence in rodents and questing adult ticks. In the empirical study, we compared areas where endemic human TBE occurs, with control sites having no reported human TBE cases. In these six sample sites located in Italy and Slovakia, we assessed deer density using the pellet group count-plot sampling technique, collected questing ticks by dragging, live-trapped rodents (primarily Apodemus flavicollis and Myodes glareolus) and counted ticks feeding on rodents. Both rodents and adult ticks were screened for TBEV infection. TBEV infection in ticks and rodents was positively associated with the number of co-feeding ticks on rodents and negatively correlated with deer density. We hypothesize that the negative relationship between deer density and TBEV occurrence could be attributed to deer (non competent hosts) diverting questing ticks from rodents (competent hosts). In fact, we observed that, after an initial increase, the number of ticks feeding on rodents reaches a peak for an intermediate value of deer density and then decreases. In order to validate and interpret in a robust theoretical framework the empirical findings regarding the effect of deer density on tick infestation on rodents and TBEV occurrence, we introduce an eco-epidemiological model to explore the dynamics of tick population and TBEV infection. Model results show hump-shaped relationships between deer density and both feeding tick on rodents and the basic reproduction number for TBEV. This suggests that deer may act as tick amplifiers, but may also divert tick bites from competent hosts, thus diluting pathogen transmission. However, our model shows that the mechanism responsible for the dilution effect is more complex than the simple reduction of tick burden on competent hosts. In fact, while the number of feeding ticks on rodents may increase with deer density, the proportion of blood meals on competent compared to incompetent hosts may decrease, triggering infection decline. As a consequence, using just the number of ticks per rodent as a TBE risk predictor could be misleading if competent hosts share habitat with incompetent hosts. Citation: Bolzoni, L., Cagnacci, F., Rosà, R., & Rizzoli, A. (2012). Deer density drives tick infestation pattern on rodents and TBE hazard: empirical and theoretical investigations. Paper presented at VIII Congresso Italiano di Teriologia, Piacenza (Italy). 2011-12-31T23:00:00Z http://hdl.handle.net/10449/22067 Title: Understanding the basis of diminished gene flow between hybridizing chromosome races of the house mouse Authors: HAUFFE, HEIDI CHRISTINE Abstract: Speciation may be promoted in hybrid zones if there is an interruption to gene flow between the hybridizing forms. For hybridizing chromosome races of the house mouse in Valtellina (Italy) distinguished by whole-arm chromosomal rearrangements, previous studies have shown that there is greater interruption to gene flow at the centromeres of chromosomes that differ between the races than at distal regions of the same chromosome or at the centromeres of other chromosomes. Here, by increasing the number of markers along race-specific chromosomes, we reveal a decay in between-race genetic differentiation from the centromere to the distal telomere. For the first time, we use simulation models to investigate the possible role of recombination suppression and hybrid unfitness in generating this pattern. We also consider epistasis and selective sweeps as explanations for isolated chromosomal regions away from the centromere showing differentiation between the races. Hybrid unfitness alone is the simplest explanation for the decay in genetic differentiation with distance from the centromere. Robertsonian fusions/whole-arm reciprocal translocations are common chromosomal rearrangements characterizing both closely related species and races within species and this fine-scale empirical analysis suggests that the unfitness associated with these rearrangements in the heterozygous state may contribute to the speciation process. Citation: Giménez, M., White, T., Hauffe, H., Panithanarak, T., & Searle, J. (2013). Understanding the basis of diminished gene flow between hybridizing chromosome races of the house mouse. Evolution, 67(5), 1446-1462. 2012-12-31T23:00:00Z