Bakteriális gének szerepe a szimbiotikus gümő inváziójában = The role of bacterial genes in the invasion of the symbiotic nodule

Hoszú távú célunk, hogy megértsük a szimbiotikus nitrogénkötő gümő kifejlődését, és azonosítsuk az invázióban fontos bakteriális géneket. E pályázatban feladatunk volt, hogy (i) elemezzük azon rkp géneket, melyek a Sinorhizobium meliloti 41 törzs specifikus KR5 kapszuláris poliszacharidjának bioszintézisében vesznek részt, (ii) meghatározzuk pontos funkcióját a pha géneknek, melyekről feltételeztük, hogy a pH-homeosztázisban fontosak. Fágreceptorban hibás baktérium és host range fág mutánsok molekuláris genetikai elemzése révén kimutattuk, hogy a 16-3 fág receptorának fontos alkotója az RkpM fehérje, és azonosítottuk a fág h génjét, mely a farki rost fehérjét kódolja. A KR5 antigénről kimutattuk, hogy csak a szimbiotikus gümő inváziójakor fontos, de nem alkotója a fágreceptornak. Befejeztük a DNS-szekvencia meghatározást az rkp-3 régióban, és vizsgáltuk az azonosított gének szerepét. Egyes és kettős rkpY mutánsok segítségével, amelyekben a második mutáció különböző rkp génekben volt kimutattuk, hogy (i) az rkpY mutánsok által termelt poliszacharid nem prekurzora a KR5 antigénnek, és hogy (ii) az rkpR gén ennek az új poliszacharidnak a bioszintézisében játszik szerepet. A pha gének szerepét kifordított membrán vezikulákon végzett fiziológiai kísérletekben vizsgáltuk. Kimutattuk, hogy a K+ adás proton kiáramlást eredményez, ami alátámasztja korábbi feltételezésünket, hogy e gének egy K+/H+ antiportert kódolnak. | Our long term goal is to understand the development of nitrogen fixing symbiotic nodule and to identify bacterial genes involved in the invasion. In this project we focus on (i) the analysis of the rkp genes involved in the biosynthesis of the strain specific KR5 polysaccharide of Sinorhizobium meliloti 41, and (ii) analysis of function of pha gene clusters presumed to be important in pH-homeostasis. The molecular genetic analysis of phage receptor bacterial and host-range phage mutants resulted in the identification of the RkpM protein as an essential part of the 16-3 phage receptor, and in the identification of h gene of the phage encoding the tail-fiber protein. The KR5 antigen were shown only to be important in the invasion of symbiotic nodule but not in the structure of phage receptor. DNA-sequence analysis of the rkp-3 region was completed and the role of the identified genes were examined. Using single and double rkpY mutants, where the second mutations were in different rkp genes, it was shown that (i) the polysaccharide produced by the rkpY mutant was not a precursor of the KR5 antigen, (ii) the rkpR gene is involved in the synthesis of this new polysaccharide. The role of the pha genes were examined on everted membrane vesicles. It was shown that addition of K+ results in proton efflux supporting our hypothesis that pha genes encode for a K+/H+ antiporter

What types of powdery mildew can infect wheat-barley introgression lines?

Peer reviewe

Einfluss von Temperatur und Nutzung auf die floristische Artenvielfalt in Getreideanbaugebieten Europas

Die Segetalflora der Getreideanbaugebiete Europas bildet auf Grund der landwirtschaftlichen Kulturgeschichte sowie der Größe der Anbaufläche einen wichtigen Bestandteil der Biodiversität. Um den Einfluss der Klimabedingungen in Verbindung mit bestehenden Nutzungsformen auf die Artenvielfalt der Segetalflora in den Getreideanbaugebieten zu prüfen, wurden Modellrechnungen basierend auf mehrjährigen Felduntersuchungen und europaweiten Klimadaten durchgeführt. Die verwendeten Modelleingangsdaten basieren auf mehrjährigen Felduntersuchungen zur Artenvielfalt der Segetalflora in Getreideanbaugebieten mit 3,5 °C bis 16,4 °C Jahresmittel der Lufttemperaturen. Die ermittelte räumliche Verteilung der Artenvielfalt zeigt europaweit große Unterschiede. Höchste Artenzahlen, die Hot-spots der Segetalflora, befinden sich in den mediterranen Getreideanbaugebieten mit bis über 410 Arten je berechneter Gitterbox von 25 km x 25 km. In ausschließlich intensiv, mit Herbizideinsatz bewirtschafteten Getreideanbaugebieten reduziert sich die floristische Artenvielfalt etwa um den Faktor 3 in den mediterranen und um 1,5 bis 2 in den gemäßigten bis kühlen Klimagebieten.Für die Sicherung der Biodiversität in Ackerbaugebieten sind aus floristischer Sicht größere Flächenanteile mit extensiven Nutzungen ohne Einsatz von Herbiziden sowie selbstbegrünte, ein- bis zweijährige Ackerbrachen erforderlich. Dadurch könnte einer durch intensive Nutzungen starken Verarmung sowie Uniformierung der Artenvielfalt in den Ackerbaugebieten Europas entgegen gewirkt werden.Stichwörter: Europa, Klima, Temperaturen, Segetalflora, Getreideanbau, Nutzungsintensitäten, räumliche Verteilung ArtenvielfaltEffects of temperature and land use on the floristic species diversity in grain field areas of EuropeSummaryThe weeds (segetalflora) in European grain-growing regions is due to the agricultural and cultural history and due to the size of the cultivated area an important component of biodiversity. Model calculations were preformed to investigate the influence of climatie conditons in conjunction with different of agricultural uses on the biodiversity of the segetalflora. As input data the model uses datasets on European climate and from field studies. These are based on several years of field studies on the biodiversity of segetalflora in grainproducing regions within a mean annual air temperature range from 3.5 °C to 16.4 °C.The calculated spatial distribution of biodiversity in Europe shows great variation. The highest number of species, considered as hot-spots of segetalflora are located in the Mediterranean grain-growing regions with over 410 species for each calculated grid (25*25km). In intensively used grain-growing regions with herbicide applications the floristic diversity is reduced by a factor of 3 in the Mediterranean and by 1.5 to 2 in temperate to cool climates.From floristic point of view large extensively used fields without herbicide applications and self greened 1-2 year old fallow fields are necessary/suitable to protect the biodiversity in agricultural areas. The implementation of such structures could counteract impoverishment and uniformity of biodiversity in intensively used agricultural areas in Europe.Keywords: Europe, climate, temperatures, weeds, segetalflora, grain field areas, land use intensity, spatial distribution of species diversit

Quality Assessment of Goldenrod, Milkweed and Multifloral Honeys Based on Botanical Origin, Antioxidant Capacity and Mineral Content

The goal of the study was to evaluate the pollen spectrum, antioxidant capacity and mineral content of four Hungarian honey types, using multivariate statistical analysis. The light colored honeys were represented by milkweed honey and a multifloral (MF) honey with dominant pollen frequency of linden (MF-Tilia); the darker ones were goldenrod honey and a multifloral honey with Lamiaceae pollen majority (MF-Lamiaceae). The pollen spectrum of the samples was established with melissopalynological analysis. The absorbance of the honeys positively correlated with the antioxidant capacity determined with three of the used methods (TRC, TEAC, DPPH), but not with ORAC. The latter method correlated negatively also with other antioxidant methods and with most of the mineral values. MF-Tilia had high ORAC value, K and Na content. The MF-Lamiaceae had the highest K, Mg, P, S, Cu and Zn content, the last five elements showing strict correlation with the TRC method. The darker goldenrod honey had higher SET values and total mineral content, than the milkweed honey. The above character-sets facilitate identification of each honey type and serve as indicators of variety. The antioxidant levels and mineral content of honeys allowed their clear separation by principal component analysis (PCA)

Developmentally regulated autophagy is required for eye formation in Drosophila

The compound eye of the fruit fly Drosophila melanogaster is one of the most intensively studied and best understood model organs in the field of developmental genetics. Herein we demonstrate that autophagy, an evolutionarily conserved selfdegradation process of eukaryotic cells, is essential for eye development in this organism. Autophagic structures accumulate in a specific pattern in the developing eye disc, predominantly in the morphogenetic furrow (MF) and differentiation zone. Silencing of several autophagy genes (Atg) in the eye primordium severely affects the morphology of the adult eye through triggering ectopic cell death. In Atg mutant genetic backgrounds however genetic compensatory mechanisms largely rescue autophagic activity in, and thereby normal morphogenesis of, this organ. We also show that in the eye disc the expression of a key autophagy gene, Atg8a, is controlled in a complex manner by the anterior Hox paralog lab (labial), a master regulator of early development. Atg8a transcription is repressed in front of, while activated along, the MF by lab. The amount of autophagic structures then remains elevated behind the moving MF. These results indicate that eye development in Drosophila depends on the cell death-suppressing and differentiating effects of the autophagic process. This novel, developmentally regulated function of autophagy in the morphogenesis of the compound eye may shed light on a more fundamental role for cellular self-digestion in differentiation and organ formation than previously thought