Oxidative Stress and Antioxidative Activity in Leaves and Roots of Carrot Plants Induced by Candidatus Phytoplasma Solani

The present study examined the effects of Candidatus Phytoplasma solani infection on antioxidative metabolism in leaves and roots of carrot (Daucus carota L.). Disease symptoms appeared at the end of June in the form of the chlorosis on some of the leaves, which became intensely red one week later, while the previously healthy leaves from the same branch becme chlorotic. A few days later, all leaves from the infected leaf branch were intensely red. Infected plants also had slower growth compared to the healthy ones with fewer leaf branches developed. The roots of infected plants were less developed, seared, or gummy with or without brown-colored root hair. The presence of the pathogen was detected by sequencing the 16S rRNA. National Center for Biotechnology Information (NCBI) BLAST analyses of the obtained sequence revealed 100% identity of tested strain with deposited Ca. Phytoplasma solani strains from various countries and hosts, all belonging to the "stolbur" group (16SrXII-A). Identity of 99.74% was found when the tested Serbian strain (MF503627) was compared with the reference stolbur strain STOL11 (AF248959). The oxidative damage of membranes in carrot cells was accompanied by a decrease in the content of photosynthetic pigments. Furthermore, for the determination of specific scavenging properties of the extracts, in vitro antioxidant assay was performed. In phytoplasma-infected carrot leaves, there was a greater reduction in the level of glutathione content (GSH); however; flavonoids and anthocyanidins seem to be responsible for the accompanied increased antioxidative capacity against hydroxyl radical and hydrogen peroxide

Occurrence and molecular characterization of Impatiens necrotic spot tospovirus in ornamentals in Serbia

A subset of ornamentals grown in Serbia were surveyed for the presence of impatiens necrotic spot tospovirus (INSV) from 2008 to 2018. Out of 1578 samples tested for the presence of the virus using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), INSV was detected in 26 Begonia sp. and four Tulipa sp. samples collected in 2008 and in 10 samples of each of Begonia sp., Impatiens walleriana and I. hawkeri 'SunPatiens' and 'New Guinea' collected in 2018. INSV was not detected in any samples collected during 2009-2017. For further confirmation, the nucleotide sequence of the INSV nucleocapsid (N) gene was obtained by reverse transcription polymerase chain reaction (RT-PCR) in two and four samples collected in 2008 and 2018, respectively. The success of mechanical transmission of INSV isolates from different hosts was variable depending on isolates. Serbian INSV isolates showed very low nucleotide diversity and they were closely related to the Chinese and Japanese isolates already reported in the literature, indicating that the Serbian isolates might be of Asian origin. Phylogenetic analysis and the median-joining haplotype network of the N gene sequences showed clustering of Serbian INSV isolates in the Asian clade into two different subclades with different recent common ancestors implying two independent introductions. The sporadic occurrence of INSV with high temporal distance is a likely consequence of virus spread through the international trade in ornamental planting material. Therefore, the establishment of the virus should be considered and prevented when introducing new plant material into the country. This is also the first report of the tulip as a natural host of INSV

Molecular phylogenetic analyses reveal a deep dichotomy in the conifer-inhabiting genusTrisetacus(Eriophyoidea: Nalepellidae), with the two lineages differing in their female genital morphology and host associations

We analyzed the phylogenetic relationships of the genusTrisetacususing two genes [cytochromecoxidase subunit I (COI) and D1-D2 region of 28S rDNA (D1-D2 28S)], a representive taxon sampling (nearly 40% of known diversity), and a large set of close and distant outgroups. Our analyses suggest the presence of a dichotomy betweenTrisetacusassociated with Cupressaceae and Pinaceae. The following smaller molecular clades were found:Pin-1(bud mites, twig sheath mites, bark gall mites, and endoparasitic mites from pinaceans),Pin-2(needle sheath mites from pines),Pin-2a(putative Nearctic group of needle sheath mites),Pin-2b(putative Palearctic group of needle sheath mites),Cup-1and2(bud, cone, seed mites and mites living under bark scales from cupressaceans). The monophyly of the recently proposed subgenusBrevithecusnested within cladeCup-2was confirmed. Ancestral character reconstruction analyses recovered: (1) Pinaceae as the ancestral hosts of Nalepellidae andTrisetacus, (2) repetitive reductions of the spermathecal tube independently occurred in two lineages ofTrisetacusfrom Cupressaceae, and (3) several mite habitats on host (galls, cones, twig sheaths, seeds, inside leaves, and under scales) are evolutionarily derived states, whereas living in buds or needle sheaths are ancestral states forTrisetacuscladesCupandPin. Using confocal microscopy, we identified six basic types of the female internal genitalia ofTrisetacusbased on shapes of the spermatheca and spermathecal tube. These genitalic types are strongly correlated with lineages recovered by molecular phylogenetic analyses, suggesting that the female genital morphology is both evolutionarily conserved and is a factor influencing macroevolutionary patterns in this group of mites

Phylogeny of the Subtribe Monoctonina (Hymenoptera, Braconidae, Aphidiinae)

Abstract: Members of the Monoctonina subtribe have long been neglected in applied studies of the subfamily Aphidiinae, due to their low economic importance, as they do not parasitize pests of cultivated plants. Consequently, data about this group are scarce, including its taxonomy and phylogeny. In the present study, we explore inter- and intraspecific genetic variation of Monoctonina species, including genera Monoctonus Haliday 1833, Monoctonia Starý 1962, Falciconus Mackauer 1959 and Harkeria Cameron 1900. We employ two molecular markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) and the D2 region of the 28S nuclear gene (28S rDNA), to analyze genetic structuring and phylogeny of all available Monoctonina species, and combine them with morphological data for an integrative approach. We report one new species, and three potentially new species which can be formally described when further specimens are available. Analysis of phylogenetic relationships within the subtribe shows a basal position for the genera Falciconus and Monoctonia, and the close relatedness of Harkeria and Monoctonus

Alelski profil izolata Xanthomonas campestris pv. campestris sa kupusa u Srbiji

Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease of cabbage (Brassica oleracea var. capitata L.), is one of the most important bacteria which affect proper cabbage growth, leading to head weight and quality losses and thereby drastically reducing its marketing value. The pathogen is genetically diverse, which is evident from the presence of eleven races worldwide and more than thirty combinations of allelic profiles. Therefore, this study aimed to determine the allelic profiles of Serbian cabbage Xcc strains obtained in 2014. The analysis was done on three selected Xcc strains whose DNA was first amplified using polymerase chain reaction (PCR) with four housekeeping genes - P-XdnaK, fyuA, gyrB, and rpoD, then sequenced, and the obtained sequences were finally used to determine allelic profiles. Allelic profiles were determined by comparison with 33 Xcc strains obtained from different hosts and regions, whose allelic profiles had been determined previously. A non-redundant database (NRDB) from the pubMLST was used for allelic profile determination and Phyloviz software for constructing a minimum spanning tree. The obtained allelic profile of all Serbian Xcc cabbage strains was 1, 3, 1, 1 for the P-X-dnaK, fyuA, gyrB and rpoD genes, respectively. This profile is assigned as sequence type 2 (ST2) and it coincides with a Portuguese B. oleracea Xcc strain, CPBF 213, originating from B. oleracea var. costata. No connection between sequence type (ST) and the host was detected.Xanthomonas campestris pv. campestris (Xcc), prouzrokovač crne truleži kupusa (Brassica oleracea var. capitata L.) svrstava se među najvažnije fitopatogene bakterije koje utiču na pravilno razviće kupusa, dovodeći do gubitka težine glavice i njenog kvaliteta i na taj način drastično smanjuje njegovu ekonomsku vrednost. Ovaj patogen je genetički heterogen, što se ogleda kroz prisustvo dokazanih jedanaest rasa i više od trideset kombinacija alelskih profila širom sveta. Zbog svega navedenog, cilj ovog rada je determinacija alelskih profila Xcc sojeva poreklom sa kupusa prikupljenih 2014. godine. Analiza je vršena kod tri reprezentativna Xcc soja čija je DNK amplifikovana primenom lančane reakcije polimeraze (PCR) sa četiri konzervativna gena - dnaK, fyuA, gyrB i rpoD, a zatim sekvencirana i korišćena za determinaciju alelskih profila. Alelski profili su određivani poređenjem sa 33 Xcc soja izolovana sa različitih domaćina i regiona, čiji su alelski profili prethodno utvrđeni. Nonredundant baza podataka (NRDB) od pubMLST je korišćena za determinaciju alaleskih profila, a Phyloviz softver za konstrukciju Minimum Spanning stabla. Dobijeni alelski profil za sve Xcc sojeve sa kupusa iz Srbije je 1, 3, 1, 1 za gene dnaK, fyuA, gyrB i rpoD, redom. Ovaj profil je označen kao tip sekvence 2 (ST2) i podudara se sa portugalskim B. oleracea Xcc sojem CPBF 213 poreklom sa B. oleracea var. costata. Veza između tipa sekvence (ST) i biljke domaćina nije pronađena

Ocena kvaliteta semena populacija paradajza iz organske proizvodnje tokom starenja

A total of six tomato seed populations, collected in the autumn of 2016 at different locations in Serbia (West (3), South (1), North (1) and East (1)), were enrolled in this study. Seeds of the tomato populations considered were produced in the organic growing system in the area of Zaovice (76 m a.s.l., chernozem), Stara Pazova, Northern Serbia (44˚ 47 '19.6" N, 20˚ 27' 56.2" E) in 2017. Analyses of the germination parameters of the tomato seed populations examined (namely the germination energy, total germination, abnormal seedlings and dead seeds of the tomato seeds considered) indicated significant (r lt 0.01) differences according to the production year (A) and the tomato seed population (B). The impact interactions (r lt 0.01) of these factors (A × B) proved significant only relative to dead seeds. A highly significant positive correlation was found between the germination energy and the total germination of the seeds considered (r = 0.8711, p lt 0.001), as well as between the amounts of their abnormal seedlings and dead seeds (r = 0.92297, p lt 0.001). The germination energy and the total germination of the tomato seeds considered were found to decrease with the increasing seed age, in contrast to the numbers of their abnormal seedlings and dead seeds which continued to increase with seed aging.Seme šest populacija/sorti paradajza prikupljeno je u jesen 2016. sa različitih lokaliteta iz Srbije: zapadne (3 populacije), južne (1), severne (1) i istočne (1). Proizvodnja semena populacija paradajza u organskom sistemu gajenja izvedena je 2017. godine na lokaciji zapadne Srbije u Staroj Pazovi, potes Zovice (76 m n.v.) 44˚ 47 '19.6" N, 20˚ 27' 56.2" E. Cilj istraživanja je bio da se izvrši ocena uticaja godine i populacije na pokazatelje kvaliteta semena paradajza tokom 2017, 2018. i 2019.. Seme je čuvano u skladištu upakovano u pvc-kesama na temperaturi ispod 15ºC, RH 50%. Analiza energije klijanja, ukupne klijavosti, neneormalnih klijanaca i mrtvog semena paradjza pokazala je visoko značajne razlike (r lt 0,01) pod uticajem faktora godina (A) i populacija semena (B). Veoma značajna interakcija (r lt 0,01) ispitivanih faktora u pogledu mrtvog semena paradajza dobijena je samo kod međusobnog uticaja faktora A × B. Zabeležena je visoko značajna korelacija (p≤0.001) između energije klijanja i ukupne klijavosti, i između broja neneormalnih klijanaca i mrtvog semena. Energija klijanja i ukupna klijavost sa povećanjem starosti semena opadaju, dok broj nenormalnih klijanaca i mrtvog semena raste. Rezultati ovog rada treba da daju doprinos u shvatanju značaja autohtonih populacija/sorti ne samo paradajza, već i autohtonih sorti semena ostalog povrća; odnosno da ukažu na značaj očuvanja genetičkih resursa za organsku poljoprivredu

Diversity of phytoplasmas identified in the polyphagous leafhopper Euscelis incisus (Cicadellidae, Deltocephalinae) in Serbia: pathogen inventory, epidemiological significance and vectoring potential

Euscelis incisus is polyphagous leafhopper that is widely distributed and abundant in diverse agroecosystems. Two generations per year allows this species to come into contact with a plethora of different phytoplasmas. We first investigated the interactions of E. incisus with phytoplasmas in different ecosystems as a bioindicator of phytoplasma diversity. Among the 510 analyzed E. incisus specimens collected from eight localities in Serbia, 53 (10%) tested positive for diverse ‘Ca. Phytoplasma’ taxa. Restriction fragment length polymorphism (RFLP) analysis and sequence comparison based on the F2nR2 fragment of the 16S rRNA gene revealed the presence of six 16S phytoplasma ribosomal groups and eight subgroups in E. incisus (16SrI-R, 16SrI-F, 16SrII-E, 16SrIII-B, 16SrIX-C, 16SrIX-E, 16SrXI-G and 16SrXII-A). The most prevalent was the 16SrXII-A phytoplasma group, represented by two multilocus stolbur phytoplasma genotypes: STOLg and Rqg31g. While the 16SrXII-A phytoplasmas were identical to the previously recorded isolates from Serbia, the 16SrI-F and 16SrI-R subgroups closely related to the previously documented 16SrI-B and 16SrI-C subgroups were recorded for the first time in Serbia. In addition, records of the 16SrIX and 16SrXI groups represent the first findings of these phytoplasma groups in Serbia. Transmission trials of ‘Ca. P. solani’ were performed with naturally infected E. incisus adults. The leafhoppers successfully transmitted stolbur phytoplasma to exposed Catharanthus roseus plants, indicating their role as a natural vector

Efikasnost bakar-citrata u zaštiti vinove loze od bolesti

The control of Plasmopara viticola and Botrytis cinerea, two of the most dangerous pathogens on grapevine, requires frequent treatments with chemicals based on weather conditions. Numerous applications of fungicides have resulted in developing fungicide resistance. Active ingredients based on copper have been used very successfully for a long time to protect grapevines against these pathogens. Application of a copper citrate formulation with high degree dissociation at a very low concentration (1%) was evaluated in field trials. The efficacy of two concentrations of copper citrate, 0.5 and 1.0%, were tested against P. viticola on grapevine in three locations, and against B. cinerea in two locations during 2018. Our results demonstrated that the concentration of 1.0% copper citrate was highly effective against P. viticola (87.4%) and B. cinerea (63.7%), compared to standard treatment (90.6 and 53.1%), under a high level of infection.Zaštita vinove loze od prouzrokovača plamenjače vinove loze - Plasmopara viticola i sive truleži - Botrytis cinerea, je vrlo kompleksna i zahteva primenu većeg broja hemijskih tretmana, u skladu sa vremenskim uslovima. Učestala primena fungicida uslovljavala je pojavu rezistentnih izolata patogena na fungicide. Različite forme bakarnih jedinjenja primenjuju se u zaštiti vinove loze dugi niz godina prilično uspešno. Primena bakar-citrata - formulacije sa visokim stepenom disocijacije u niskoj koncentraciji (1,0%) ispitivana je u poljskim uslovima. Efikasnost dve koncentracije bakar-citrata - 0.5 i 1.0% je testirana u suzbijanju P. viticola i B. cinerea na vinovoj lozi na tri (dva) lokaliteta, tokom 2018 godine. Naši rezultati pokazuju da je ispitivana koncentracija od 1,0% bakar-citrata ispoljila zadovoljavajući efekat na P. viticola (87,4%) i B. cinerea (63,7%) u odnosu na primenjene standarde (90,6% i 53,1%) u uslovima visokih zaraza

Bakterioze tikava

Production of cucurbits has a long tradition worldwide. Cucumber, watermelon and melon production is very important for many producers in some parts of Serbia. These crops are especially susceptible to phytopathogenic bacteria which can cause substantial losses in years with favorable weather conditions. In this paper major bacterial diseases of cucurbits are described, such as bacterial fruit blotch caused by Acidovorax citrulli, angular leaf spot caused by Pseudomonas syringae pv. lachrymans, bacterial spot caused by Xanthomonas campestris, bacterial wilt caused by Erwinia tracheiphila, cucurbit yellow wine disease caused by Serratia marcescens, bacterial leaf spot, caused by Pseudomonas syringae pv. syringae, inducing bacterial soft rot caused by Pectobacterium species.Biljke familije Cucurbitaceae imaju dugu tradiciju proizvodnje širom sveta. U pojedinim krajevima Srbije, naročito severnim, proizvodnja krastavca, lubenice i dinje predstavlja primarno zanimanje mnogih poljoprivrednih gazdinstava. Pojava bakterioza u godinama sa uslovima koji pogoduju nastanku infekcije, može značajno ugroziti proizvodnju ovih biljaka. U ovom radu predstavljena su najznačajnija bakteriozna oboljenja biljaka familije Cucurbitaceae, među kojima su: bakteriozna mrljavost plodova lubenice, čiji je prouzrokovač Acidovorax citrulli, uglasta pegavost lišća krastavca, prouzrokovana bakterijom Pseudomonas syringae pv. lachrymans; bakteriozna uvelost krastavca prouzrokovana vrstom Erwinia tracheiphila; bakteriozna pegavost koju prouzrokuje Xanthomonas cucurbitae; potom žutilo vreža, čiji je prouzrokovač Serratia marcescens; zatim bakteriozna lisna pegavost prouzrokovana Pseudomonas syringae pv. syringae; kao i bakteriozna vlažna trulež prouzrokovana vrstama roda Pectobacterium

The Incidence and Genetic Diversity of Potato virus S in Serbian Seed Potato Crops

It is essential that certified potatoes are free from known viruses which can negatively affect quality and yield. However, very little is known about the distribution and frequency of Potato virus S (PVS) in Serbia. Until 2014, PVS was present sporadically in the domestic seed potato production. The incidence of PVS was studied by a molecular method over 3 years (2014-2016) in four important potato-growing regions (Moravidd. Zlatiborski, Raski and Macvanski) and in different cultivars. The results showed that the incidence of PVS increased steadily over 3 years from 1.52 to 8.84%. The Moravicki region had the highest incidence (13.06%) and Desiree was the most susceptible cultivar with a mean PVS incidence of 8.2% followed by Marabel and Riviera. The highest significant statistical difference was between the cultivars and in the interaction between cultivars and regions. A detailed phylogenic analysis of the tested isolates contained that Serbian PVS belongs to PVSO. Of the 18 Serbian PVS isolates included in this study, eight were grouped into the PVSO cluster and formed a subgroup (O-I) with isolates from the USA, Syria, Korea and Chile. Ten Serbian isolates of PVS together with the isolates from Iran were clustered in a branch of subgroup O-VII. This study constitutes the fast report of PVS isolates in Serbia which are capable of infecting Chenopodium quinoa and inducing the symptoms of local chlorotic lesions