Populacija bakterija u bakterioznim tumorima koštičavog voća u Srbiji

Proizvodnja koštičavog voća zauzima značajno mesto u voćarstvu Srbije. Tradicionalno, najviše se gaji šljiva sa sve raznovrsnijim sortimentom u poslednjih desetak godina, dok je proizvodnja trešnje, višnje i kajsije sve više zastupljena u pojedinim regionima zemlje, nekoliko decenija unazad. Prema podacima FAO za 2021. godinu, prinos šljive bio je oko 40.000 t, a trešanja i višanja oko 15.000 t. Iste godine, proizvedeno je oko 30.000 t kajsije. Uspešnu proizvodnju često ometa pojava različitih biljnih bolesti. Od bakterioznih oboljenja, bakteriozni rak korena i korenovog različitih gajenih vrsta zauzima značajno mesto. S obzirom da je utvđeno da bakteriozne tumore osim tumorogenih, naseljavaju i druge vrste bakterija, deo istraživanja posvećen je izučavanju sastava populacije mikroorganizama tumora. Tokom 2020. i 2021. godine na području Srbije, prikupljeni su uzorci šljive, trešnje, višnje i kajsije sa izraženim simptomima bakterioznog raka. Primenom savremene metode sekvenciranja umnoženih produkata regiona V3-V4 16S rRNK gena, dobijene su amplikonske sekvence (ASV), koje su dalje obrađene. Na taj način, determinisane su najzastupljenije vrste bakterija u testiranim uzorcima. Patogena vrsta R. tumorigenes detektovana je kod trećine od ukupnog broja testiranih uzoraka. U uzorcima u kojima je prisutna, njena relativna zastupljenost iznosi do ~ 4%. Rhizobium spp. prisutan je do ~ 11% u uzorcima šljive, odnosno ~ 6% u uzorcima kajsije i ~ 5% trešnje i višnje. Vrste roda Bacillus detektovane su u svim testiranim tumorima, sa udelom i do ~ 53% kod uzoraka šljive. U tumorima na trešnji i višnji, prisutne su vrste roda Rachnella u koncentraciji do ~ 23%, kao i Cutibacterium do ~ 14%. Vrste roda Pseuodmonas detektovane su u uzrocima tumora na kajsiji (do ~4%). Osim navedenih, u uzorcima su prisutni i drugi taksoni u nižim koncentracijama. Predstavljeni rezultati su deo projekta koji se sprovodi u cilju boljeg razumevanja odnosa između patogenih i nepatogenih vrsta u zajednici mikroorganizama tumora. Imajući u vidu sve veći značaj pojave bakterioznog raka u različitim zasadima širom sveta, kao i potencjalni benefit mikroorganizama koji naseljavaju tumore u biološkoj kontroli i opštem stanju biljke domaćina, istraživanja na ovu temu će biti od značaja i u narednom periodu

Asymmetric Introgression and Cryptic Natural Hybridization between Two Species of Teucrium Section Polium (Lamiaceae) on the Balkan Peninsula

In this work, we analyzed the morphology and genetic structure of Teucrium montanum, T. capitatum and their hybrid T. × rohlenae from three syntopic populations. A morphometric study showed that the parents and their hybrids exhibited continuous morphological variation, with the hybrid positioned exactly between the parents. Genetic analysis revealed that plants morphologically identified as T. × rohlenae are fertile hybrids that produce hybrid swarms dominated by later-generation hybrids. This suggests that introgression, rather than speciation, is the more likely outcome of hybridization between these plant species. The extent and direction of gene flow between the two species differed markedly between the three syntopic localities. At the Trilj locality, it was clearly unidirectional, with T. capitatum playing the dominant role. At the Sićevo locality, gene flow was slightly asymmetric, favoring the genetic background of T. capitatum, while at the Sliven site, it was completely asymmetric in the opposite direction. The extreme case of unidirectional gene flow was observed at the Trilj locality where plants morphologically identified as T. montanum could not be genetically distinguished from T. capitatum. This suggests that interspecific hybridization occurred long ago, leading to introgression and cryptic hybrids, blurring of species boundaries and generating evolutionary noise

Polyphasic study of phytopathogenic bacterial strains associated with deep bark canker of walnut in Serbia revealed a new species, Brenneria izbisi sp. nov

Serious outbreaks of walnut deep bark canker were observed on young walnut trees (Juglans regia L.) in two localities in the northern part of Serbia during 2020. From the symptomatic walnut tissues, two types of bacterial colonies were isolated, predominantly, light cream, circular and smooth colonies, as well as small, yellowish, mucoid and convex ones. PCR analysis and phenotypic assays suggested that the former group belongs to Brenneria spp., while the latter isolates were identified as Xanthomonas arboricola pv. juglandis. Within the Brenneria group, two strains were identified as Brenneria nigrifluens, while other 15 strains did not belong to any Brenneria species described so far. Therefore, we selected four representative strains of the unknown Brenneria sp. and subjected them to polyphasic analysis. As expected, in a phylogenetic tree based on partial 16S rDNA sequences, four novel strains grouped with other Brenneria representatives, and showed close phylogenetic relationship to Brenneria salicis. Furthermore, multilocus sequence analysis (MLSA) based on the partial sequences of atpD, gyrB, infB and rpoB housekeeping genes and core-genome phylogeny indicated that the studied strains form a novel and a clearly separate Brenneria lineage. Overall genome relatedness indices showed that they represent a new Brenneria species. The new species can be differentiated from the other Brenneria spp. infecting walnut and closely related B. salicis strains based on phenotypic characteristics, as well. Moreover, the pathogenicity tests on two-year-old walnut plants proved the ability of strains to cause necrosis and longitudinal black lesions and cracks on the trunk and branches of walnut trees. Overall, polyphasic characterization showed that the studied strains isolated from walnut with symptoms of deep bark canker represent a novel species of the genus Brenneria for which the name Brenneria izbisi sp. nov. is proposed. The type strain of B. izbisi is KBI 423T (= CFBP 9035T = LMG 32479T). To facilitate rapid identification of newly described species, a conventional PCR protocol and primers targeting the putative gene hrpP, were developed. Further study should reveal the potential role of each pathogen isolated from symptomatic walnut in disease development as well as possible interaction between them

Generalized habitat map of Serbia

The generalized habitat map of Serbia is one of the products of the project carried out for the needs of the Institute for Nature Protection of Serbia by the Faculty of Biology University of Belgrade in cooperation with the geomatics company MapSoft d.o.o. The map was created using an adapted methodology for extracting different habitat types from remote sensing data. To interpret the basic habitat types, the following input datasets were used: Sentinel-2 satellite data, EU-DEM terrain elevation data, Basic land cover map, Copernicus pan-European high resolution layers, Open Street Map data, pedological and geological map of Serbia, and numerous training data. The map was created by integrating the rasters of each habitat type into a single raster, separating additional habitat subtypes by crossing them with additional sources (geologic and pedological map, basic land cover map, etc.). The final results are presented in the form of a spatial raster, with 32 cartographic classes defined based on the typology of habitats according to the Rulebook on Habitats of Serbia. In addition, manual vectorization of several other habitat types (springs - 37,284 objects, caves - 499 objects, waterfalls - 109 objects) was performed, and these results are provided in the form of vector point entities

Specificity and sensitivity of three pcr-based methods for detection of erwinia amylovora in pure culture and plant material

Three PCR methods, referred in this study as,conventional" "nested" and,chromosomal" PCR and suggested for routine detection of Erwinia amylovora in pure culture and plant material, were evaluated according to their specificity and sensitivity. Specificity of PCR methods was analyzed by using 42 strains of E. amylovora, originating from different locations and plant species, with diverse PFGE profiles, representing distant populations of the pathogen. Sensitivity of PCR protocols in pure culture was studied by using nine different concentrations of E. amylovora in sterile ultrapure water as a template in PCR reactions. In order to study inhibitory effect of plant DNA and other inhibitors on sensitivity of the three PCR methods bacterial dilutions were mixed with plant macerate of pear, apple and quince prior to the PCR reaction. In specificity assays, tested PCR protocols were able to detect all E. amylovora strains regardless of the host of the strain, its origin or PFGE group, indicating primer specificity. On the other hand, sensitivity among tested methods varied, depending on bacterial concentration and selected plant material used in the PCR. When working with pure cultures nested PCR showed the greatest sensitivity by detecting 1.9 bacterial cells per PCR reaction, followed by detection limit of 9.5 cells per PCR reaction with conventional PCR and 1.9.105 cells/PCR reaction with chromosomal PCR. In spiked samples plant inhibitors either did not affect or they decreased the sensitivity of the PCR reaction, depending on the protocol and/or type of plant macerate. In our experiments, inhibitors from pear and quince macerates did not affect sensitivity of nested PCR, while apple macerate reduced its sensitivity by a factor of 10. Conventional PCR protocol was able to detect 95 cells/PCR reaction in pear and apple macerate, but only 9.5.103 cells/PCR in quince macerate. Greatest decrease in sensitivity of the PCR method was observed in spiked samples with chromosomal PCR since bacterial DNA was not detected in each of the spiked samples. Our research shows that all three PCR protocols are specific for detection of E. amylovora, but nested PCR proved to be most sensitive when working with pure cultures and plant material

The alpine scrubs and dwarf heaths of the Balkan Peninsula - an exceptional center of floristic richness and endemism

Alpine scrubs (Roso pendulinae-Pinetea mugo) and dwarf heaths (Loiseleurio procumbentis-Vaccinietea) are an exceptional assemblage of rich floristic units which contribute significantly to the overall diversity on the Balkan Peninsula. The main edificators of these types of habitats are mostly glacial relicts. Additionally, they are of the arctic, alpine, and boreal distribution types, which further emphasises their importance from the conservation point of view. We investigated their taxonomic richness, endemism, patterns of spatial distribution and diversification in the central Balkans as well as their coenotic composition using a comprehensive dataset (15,609 species occurrence data). The analyses were conducted at three hierarchical levels taking into account the ecological and geographic diversity of the alpine scrubs and dwarf heaths in the study area. The results obtained showed that in the alpine scrubs and dwarf heaths of the central Balkans 902 taxa (829 species and 73 subspecies) had been recorded, and that the proportion of endemics in these habitats is extremely high (ca. 22%). Our results further showed that in 180 randomly selected plots of medium size (≥ 10 and < 100 m2 ), the registered regional floristic richness for the unique sample size was 527 species, placing the alpine region of the Balkan Peninsula in second place among the richest alpine regions in the world. Moreover, significant regional differences in species composition were observed within the research area, with floristic richness and diversity increasing from north to south

Draft Genome Sequences of Agrobacterium nepotum Strain 39/7(T) and Agrobacterium sp. Strain KFB 330

Tumorigenic strains of Agrobacterium spp. are responsible for crown gall disease of numerous plant species. We present here draft genome sequences of nonpathogenic Agrobacterium nepotum strain 39/7(T) (CFBP 7436(T), LMG 26435(T)), isolated from crown gall tumor on Prunus cerasifera, and tumorigenic Agrobacterium sp. strain KFB 330 (CFBP 8308, LMG 28674), isolated from galls on raspberry

Numerična analiza travišč v katerih prevladuje Sesleria juncifolia agg. v Srbiji

Phytosociological and numerical analyses of grasslands dominated by Sesleria juncifolia s.l. in Serbia were performed in order to resolve their syntaxonomy and nomenclature. Twelve relevés were sampled on Mt. Mučanj (western Serbia), which were then compared with similar relevés from other parts of the Balkan Peninsula by means of numerical analyses. The relevés were classified using cluster analysis, while the ordination was conducted using Detrended Correspondence Analysis (DCA). The results suggest the occurrence of two floristically well defined Dinaric associations in Serbia: Seslerio juncifoliae-Edraianthetum graminifolii ass. nova from Mt. Mokra Gora (Oxytropidion urumovii, Elyno-Seslerietea) and Diantho petraeae-Seslerietum juncifoliae ass. nova (Chrysopogono-Saturejion, Festuco-Brometea) from Mt. Mučanj.Naredili smo fitocenološko in numerično analizo travišč v katerih prevladuje vrsta Sesleria juncifolia s.l. in predstavili sintaksonomske in nomenklaturne rešitve. Dvanajst vegetacijskih popisov smo naredili na gori Mučanj (zahodna Srbija) in jih z numeričnimi metodami primerjali s podobnimi popisi z drugih delov Balkanskega polotoka. Popise smo klasificirali s klastrsko metodo, za ordinacijo smo uporabili korespondenčno analizo z odstranjenim trendom (DCA). Rezultati kažejo na obstoj dveh floristično dobro utemeljenih dinarskih endemičnih asociacij v Srbiji: Seslerio juncifoliae-Edraianthetum graminifolii ass. nova z Mokre Gore (Oxytropidion urumovii, Elyno-Seslerietea) in Diantho petraeae-Seslerietum juncifoliae ass. nova (Chrysopogono-Saturejion, Festuco-Brometea) z gore Mučanj

Morphological diversification of Teucrium montanum L. sensu lato on the Balkan Peninsula

Teucrium montanum L. is a semi-woody evergreen small shrub distributed in southern and central Europe, Asia Minor, and Algeria in North Africa. The species has a very wide ecological valence occurring in various Mediterranean, sub-Mediterranean, continental as well as oro-Mediterranean and Alpine habitats. Due to its wide ecological valence and broad distribution, T. montanum displays high morphological variability, which is reflected in a large number of described taxa associated with it. In Europe, about thirty taxa have been described at specific and infraspecific levels, of which only T. montanum subsp. montanum and T. montanum subsp. helianthemoides (Adamović) Baden are accepted, while all the others are considered synonyms of T. montanum. The observed morphological diversity is reflected in the presence of six taxa described from the Balkan Peninsula: T. montanum subsp. helianthemoides, T. montanum var. hirsutum Boiss., T. montanum var. modestum Heldr., T. montanum var. parnassicum Čelak., T. pannonicum A. Kern., and T. skorpili Velen. During field research throughout the Balkans, seven morphologically more or less well-defined groups with relatively solid geographical differentiation were observed. Five of the seven groups fit the already described infraspecific taxa, while two groups are morphologically specific but do not correspond to the existing taxa. The aim of this study was to describe the overall morpho-anatomical variability of T. montanum sensu lato in the Balkans and to determine whether the seven identified groups can be distinguished based on morpho-anatomical characters. The most typical populations of these groups could be separated quite well based on the quantitative morphological traits. Multivariate analysis of all samples showed a solid separation of three groups and a significant number of individuals with intermediate positions. Other groups did not show statistical diversification but possess a specific combination of morphological characters by which they can be identified.Usmeno izlaganje na skupu 7th Croatian Botanical Symposium with international participation (7. Hrvatski botanički simpozij s međunarodnim sudjelovanjem), Zagreb, September 12-14, 2022

Novo destruktivno oboljenje krompira - zebrasti čips

Potato production provides one of the main sources for food production, processed either at home or by the industry. Plant diseases are often limiting factor in cultivation of this crop, leading to reduction of yield and tuber quality. Zebra chip disease, caused by a floem-limited bacterium, belonging to the genus Candidatus Liberibacter, is a new, economically important disease of potato and other solanaceous plants. It is widespread in commercial potato fields in USA, Mexico, Central America, New Zealand, and was recently reported in Europe. The disease reduces yield, but most significant damage occurs due to the symptom development on tubers and loss of their marketability. Given the importance of potato production in our country, the goal of this paper is to raise the awareness about the disease occurrence and distribution, discuss the main characteristics of this relatively unknown pathogen, detection and identification methods necessary for the successful and timely diagnosis, epidemiology, symptomatology and disease management.Krompir je biljna vrsta čija proizvodnja ima veoma značajnu ulogu u obezbeđivanju hrane, a takođe i sirovine za industrijsku preradu. Pojava štetnih organizama neretko predstavlja ograničavajući faktor gajenja ove biljke, jer dovodi do smanjenja prinosa i pogoršanja kvaliteta krtola. Oboljenje nazvano zebrasti čips, koje prouzrokuje fastidiozna bakterija iz roda Candidatus Liberibacter, je novo, ekonomski značajno oboljenje biljaka iz familije Solanaceae, čiji je glavni domaćin krompir. Patogen, takođe, zaražava i srodne vrste kao što su paradajz i paprika. Ovo destruktivno oboljenje rasprostranjeno je u proizvodnim područjima Amerike, Novog Zelanda, a nedavno je otkriveno i na evropskom kontinentu. Kao posledica infekcije, dolazi do smanjenja prinosa zaraženih biljaka, dok najznačajnije štete nastaju usled pojave simptoma na krtolama i gubitka njihove tržišne vrednosti. S obzirom na značaj proizvodnje krompira, paradajza i paprike u našoj zemlji, cilj ovog rada je da se ukaže na pojavu i rasprostranjenost oboljenja, glavne karakteristike ovog malo poznatog patogena, metode detekcije i identifikacije neophodne za pouzdanu i pravovremenu dijagnozu oboljenja, epidemiologiju, simptomatologiju i mere zaštite