Rubbery taproot disease of sugar beet in Serbia associated with 'Candidatus phytoplasma solani'

Rubbery taproot disease (RTD) of sugar beet was observed in Serbia for the first time in the 1960s. The disease was already described in neighboring Bulgaria and Romania at the time but it was associated with abiotic factors. In this study on RTD of sugar beet in its main growing area of Serbia, we provide evidence of the association between 'Candidatus Phytoplasma solani' (stolbur phytoplasma) infection and the occurrence of typical RTD symptomatology. 'Ca. P. solani' was identified by PCR and the sequence analyses of 16S ribosomal RNA, tuf, secY, and stamp genes. In contrast, the causative agent of the syndrome “basses richesses” of sugar beet-namely, 'Ca. Arsenophonus phytopathogenicus'-was not detected. Sequence analysis of the stolbur strain's tuf gene confirmed a previously reported and a new, distinct tuf stolbur genotype (named 'tuf d') that is prevalent in sugar beet. The sequence signatures of the tuf gene as well as the one of stamp both correlate with the epidemiological cycle and reservoir plant host. This study provides knowledge that, for the first time, enables the differentiation of stolbur strains associated with RTD of sugar beet from closely related strains, thereby providing necessary information for further epidemiological work seeking to identify insect vectors and reservoir plant hosts. The results of this study indicate that there are differences in hybrid susceptibility. Clarifying the etiology of RTD as a long-known and economically important disease is certainly the first step toward disease management in Serbia and neighboring countries.This is the peer reviewed version of the following article: Ćurčić Ž., Stepanović J., Zübert C., Taški-Ajduković K., Kosovac A., Rekanović E., Kube M., Duduk B. Rubbery taproot disease of sugar beet in Serbia associated with 'Candidatus phytoplasma solani'. Plant Disease 2021, 105 (2), 255 – 263. [https://doi.org/10.1094/PDIS-07-20-1602-RE]

Complex microparticulate systems based on glycidyl methacrylate and xanthan

cited By 10International audiencePorous microparticles based on glycidyl methacrylate, dimethacrylic monomers [ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate] and xanthan gum were synthesized by aqueous suspension polymerization method in the presence of toluene as diluent using two types of initiators: benzoyl peroxide and ammonium persulfate. The G microparticles based on glycidyl methacrylate and dimethacrylic monomers and X microparticles based on glycidyl methacrylate, xanthan and dimethacrylic monomers were characterized by various techniques including FT-IR spectroscopy, TG analysis, SEM analysis and DVS method. The specific surface areas were determined by DVS method, while the copolymer porosities and pore volume were obtained from the apparent and skeletal densities. The results have indicated that xanthan was included in the crosslinked matrix by means of covalent bonds. X microparticles have a porous structure with higher specific surface area (129-44 m2/g) and higher sorption capacities compared with G microparticles (69-31 m2/g). © 2014 Elsevier Ltd

Polymer-metal complexes based on gellan

cited By 4International audienceBy dropwise adding solutions of gellan (Gll) or gellan + poly(vinyl alcohol) (PVAL) mixture into different metal salt solutions-FeCl3 · 6 H2O, FeCl2 · 4 H2O, CoCl 2 · 6 H2O, CuCl2 · 2 H 2O-at 30 °C under constant stirring, preparation of spherical microparticles based on polymer-metal complexes has been performed. FT-IR spectroscopy, TGA analysis and swelling measurements of these microparticles in water showed the influence of the metal type ions on their structure, thermal stability and water swelling capacity. The FT-IR spectroscopy allows to explain the mechanism of polymer-metal complexes formation and the optical microscopy showed that the microparticles obtained had good sphericity with average diameter ranging from 719 μm to 830 μm. The thermal stability of the polymer-metal complexes was found to be higher than that of the gellan

Surface characterization and drug release from porous microparticles based on methacrylic monomers and xanthan

cited By 7International audiencePorous crosslinked microparticles based on glycidyl methacrylate and xanthan were prepared by suspension polymerization and used for loading theophylline, a bronhodilatator drug, in order to obtain new drug delivery systems. The surface morphologies observed by means of SEM and AFM analysis demonstrated that microparticles show a spherical shape and are characterized by a porous structure. The presence of xanthan in the structure of microparticles leads to a decrease of surface roughness and pore diameters as well as to an increase of hydrophilicity degree compared to the micropaticles based only on glycidyl methacrylate. To analyze the in vitro release data various mathematical models were used, such as, first order, Higuchi model, Korsmeyer-Peppas model and Baker-Lonsdale model. Based on the highest values of the correlation coefficient, the analysis of the kinetic data indicate that drug release from G1 and X1 porous microparticles fits similarly well to the first order and Higuchi models and diffusion was the dominant mechanism of drug release. © 2015 Elsevier Ltd

Engineering adaptive gene circuits in bacteria mastering game playing by reinforcement learning

Learning to solve problems is central to artificial and living intelligent systems. Although physical and chemical systems mimicking neural connectivity have been shown to solve complex problems, no living system with a synthetic genetic construction has ever been reported to learn complex algorithms such as playing board games — a classic benchmark for artificial intelligence. Engineering a synthetic genetic system in living cells able to learn and play even the simplest board games, such as tic-tac-toe, has remained elusive because it requires not only a set of gene circuits implementing the needed decision algorithms but also an adaptive memory system that can predictably adjust their strength through learning. We will report that engineered Escherichia coli encoding a library of new genetic switches — we call memregulons — that act as both memory systems and logic gates, can learn to produce predictable gene regulation. As the memregulon devices allow the design of gene circuits with predictable behaviour, we use them to implement in living cells a computational algorithm allowing the bacteria to master playing tic-tac-toe by using reinforcement learning. Learning is achieved by persistently modifying the relative expression of memregulons by applying external chemicals after each training game is won or lost, leading to new decisions. Bacteria learn by playing against other players or other bacteria in an unsupervised manner and the same library allows them to learn other types of games or algorithms