Ogorčice so organizmi, ki jih zaradi njihove številčnosti, raznolikosti in prilagodljivosti najdemo praktično povsod. Medtem ko je večina ogorčic koristnih, pa poznamo tudi take, ki s svojim ...parazitiranjem povzročajo škodo. Med škodljive ogorčice uvrščamo tudi rastlinsko-parazitsko vrsto Xiphinema index. Najdemo jo lahko v bližini korenin žlahtne vinske trte (Vitis vinifera L.), saj je prav ta njena glavna gostiteljica. Ogorčica ni tako problematična z vidika neposrednega napada korenin, ampak vinski trti predstavlja grožnjo zaradi prenosa in vnosa virusa pahljačavosti listov vinske trte (GFLV) iz rodu Nepovirus. Virus namreč na vinski trti povzroči bolezen kužne izrojenosti vinske trte, kar vodi v ekonomsko nekonkurenčnost vinogradov. Okužba lahko privede tudi do več kot 80 % izpada pridelka. V izogib nenadzorovanemu širjenju ogorčic in posledično okužbam v vinogradih je pomembna preventiva, saj poleg prenosa s sadilnim materialom, pomembnega prenašalca predstavljata tudi kmetijska mehanizacija in fizični prenos z orodjem. Ker se je kemično zatiranje ogorčice X. index zaradi njene trdoživosti in razporeditve v tleh izkazalo za neučinkovito, je potrebno v prihodnje stremeti k alternativnim in predvsem učinkovitejšim pristopom. Poleg vmesnih posevkov so preverjali delovanje pripravkov na podlagi nekaterih bakterij in gliv, ki predstavljajo velik potencial za nadaljnja raziskovanja.
The tropical root-knot nematode (RKN) Meloidogyne inornata infects soybean, tobacco, yacon, common bean and Anthurium andreanum. This species was reported as the cause of damage in commercial yacon ...production in Brazil, and has potential to cause losses to common bean crops. Potato (Solanum tuberosum L.) cv. Désirée infected with M. inornata exhibited typical RKN galls on roots and tuber surfaces, similar to those caused by the two quarantine pathogens M. chitwoodi and M. fallax, and the non-quarantine M. luci. This study has indicated that M. inornata has considerable potential to cause severe damage to potato tubers. The potential spread of this pathogen into new areas should be assessed, as it can damage potato tubers and could be a problem for economically important crops. Ensuring pest-free seed potatoes is important to prevent dissemination and establishment of M. inornata in uninfested areas. Phytosanitary measures and monitoring programmes developed to prevent spread of this pest in Europe may be warranted.
Meloidogyne luci is a polyphagous plant parasitic nematode species with a potential to cause great losses in agricultural production. M. luci can parasitize over thirty important crop species as well ...as ornamentals, herbs and weeds. In this report we documented a weed plant common groundsel (Senecio vulgaris L.) as a new naturally-infected host species which could act as a reservoir for this pest.
In years 2015 and 2016 around 200 specimens of ladybird species Harmonia axyridis were collected in Slovenia. Ladybirds were dissected and checked under stereomicroscope for presence of nematodes. ...Nematodes were discovered in samples of ladybirds H. axyridis collected at Brdo pri Lukovici and Trboje. The incidence of parasitized ladybirds was around 30 %. Nematodes were analysed morphometrically and the characteristic features of Parasitylenchus bifurcatus nematodes were observed: straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform females and juvenile males. The identity was confirmed with 18S rDNA region sequence (acc. no. LT629306 and LT629307) which showed high similarity (>99.9 % nucleotide identity) to the P. bifurcatus sequences in the public domain. This is a first report of P. bifurcatus nematode species found parasitizing ladybird Harmonia axyridis in Slovenia. The species compromises fecundity of its host and has therefore a potential to be used as a biological control agent to control high abundance of invasive H. axyridis ladybirds.
A new needle nematode, Longidorus carniolensissp. n., recovered from the soil around the roots of grapevine Vitis vinifera L. from Slovenia, is described and illustrated. Longidorus carniolensisis an ...amphimictic species, characterised by females with a moderately long (L=5.6-8.2 mm) and plump (a=51-72.4, ave. 66.3) body, assuming a spiral to C-shape when heat relaxed. Head region continuous, anteriorly almost flat, lip region 23-25 µm wide; guiding ring situated posteriorly (42-47 μm, 43-50 μm in males), odontostyle long (ave. 146.6 (136-157) μm); pharyngeal glands with normal location, their nuclei of approximately equal size; tail bluntly conoidal to almost hemispherical. Males abundant, spicules slender and long (122-145 μm), ventromedian supplements 13-17, irregularly spaced, preceded by an adanal pair. Four juvenile stages present, the first stage juvenile with bluntly conoidal tail. Codes for identifying the new species when using the key by Chen et al. (1997) are: A 56, B 4, C 4, D 1, E 4, F 35, G 1, H 1, I 2. The new species is morphologically the most similar to Longidorus poessneckensis Altherr, 1974, Longidorus macrosoma Hooper, 1961, Longidorus caespiticola Hooper, 1961, Longidorus helveticus Lamberti et al., 2001, Longidorus macroteromucronatus Altherr, 1974, Longidorus pius Barsi & Lamberti, 2001, Longidorus raskii Lamberti & Agostinelli, 1993, Longidorus kheirii Pedram et al. 2008, Longidorus silvae Roca, 1993, Longidorus iuglandis Roca et al., 1985, Longidorus vinearum Bravo & Roca, 1995 and Longidorus major Roca & d'Erico, 1987, but differs from these species either by the body and odontostyle length, position of guide ring, head region and tail shape or the shape of the first stage juvenile tail. Sequence data from the D2-D3 region of the 28S rDNA distinguishes this new species from other speciesof the genus Longidorus with known sequences. Relationships of Longidorus carniolensissp. n. with other Longidorus species based on analysis of this DNA fragment and morphology are discussed.
Expansins are a group of plant cell wall loosening proteins. In animals, functional expansin (EXPB1) has been discovered in the golden potato cyst nematode Globodera rostochiensis. In plant-parasitic ...nematodes expansins act as the parasitism factors or effectors. Molecular variability of another expansin (expB2) gene was evaluated in diverse populations of the G. rostochiensis. 3D modelling of GR-EXPB2 protein sequences revealed variants with different tertiary protein structure. Superimposing PDB structures of the protein model of common type protein with two longer variants revealed difference in position of one loop in the two longer proteins. All longer GREXPB2 variants originated from South America.
Root-knot nematode (RKN) Meloidogyne ethiopica is quite unknown tropical plant parasitic species found in Slovenia and Europe in 2003 for the first time. The species is able to parasitize several ...economically important agricultural crops and therefore is very difficult to control. In our research, several approaches which can be used for M. ethiopica control were tested in pot experiment. The effects of some insecticides which are often used in the production in greenhouses, natural compounds as aqueous extract of Tagetes erecta, and the commercial natural product Azadirachtin (NeemAzal-T/S) extracted from the seeds of Indian Neem tree (Azadirachta indica) on the M. ethiopica reproduction were assessed. Test plants treatments with natural compounds reduced nematode multiplication by nearly 3 – 6 times compared to control while foliar application of Thiacloprid as well as Imidacloprid had no effect on nematode reproduction. The treatment with Volaton G granulates (Phoxim) for ground application resulted in no nematode multiplication. Additionally, M. ethiopica reproduction ability on the tomato cultivar “Venezia” which have a Mi gene for resistance to M. incognita was tested.
Expansins are a group of plant cell wall loosening proteins. In animals, functional expansin (EXPB1) has been discovered in the golden potato cyst nematode Globodera rostochiensis. In plant-parasitic ...nematodes expansins act as the parasitism factors or effectors. Molecularvariability of another expansin (expB2) gene was eva- luated in the diverse populations of the G. rostochiensis. Comparison of the expB2 genestructure in the two potato cyst nematode species, G. rostochiensis and G. pallida, revealed lack of all four introns in expB2 gene of G. pallida species. Possible loss of introns in Gp-expB2 is discussed.
Root-knot nematode (RKN)
Carneiro, Correa, Almeida, Gomes, Deimi, Castagnone-Sereno, and Karssen, 2014 was described from Brazil, Chile and Iran, parasitizing in various crops (Carneiro et al. 2014). ...It was later also described from Slovenia, Italy, Greece, Portugal, Turkey and Guatemala (review in Gerič Stare et al. 2017). It is considered an extremely damaging pest as it has a wide host range and infects numerous higher plants, including monocotyledons and dicotyledons as well as herbaceous and woody plants. This species was included in the European Plant Protection Organisation Alert List of harmful organisms. In Europe,
has been detected in both greenhouse and field agricultural production (review in Gerič Stare et al. 2017). Furthermore,
has been shown to survive winter in the field under continental and sub-Mediterranean climatic conditions (Strajnar et al. 2011). In August 2021, an official survey for quarantine RKN in Serbia (Province Vojvodina) revealed in a greenhouse in the village of Lugovo (43043'32,562; 19008'55,168), near Sombor, yellowing, stunning and extensive root galls on tomato (
L.) cultivar Diva F1 caused by an unknown
sp. (Fig. 1). As correct identification is essential for effective pest management program, the next step was to identify the nematode species. Morphological characterization performed on freshly isolated females revealed perineal patterns similar to
(Kofoid and White, 1919) Chitwood, 1949. The shape was oval to squarish with the dorsal arch rounded to moderately high and without shoulders. The dorsal striae were wavy and continuous. The ventral striae were smooth and the lateral lines were weakly demarcated. The perivulval region was without striae (Fig. 2). The female stylet was robust with well-developed knobs and the stylet cone slightly curved dorsally. Although morphological characters was very variable, the nematode was suspected as
based on comparison with originally described
and
populations from Slovenia, Greece and Turkey. Identification was achieved with subsequent species-specific PCR and sequence analysis. The nematode was determined to belong to the tropical RKN group and the
group using two PCR reactions as described by Gerič Stare et al. (2019) (Figs. 3 and 4). Identification was confirmed by species-specific PCR of
as described by Maleita et al. (2021), and a band of approximately 770 bp was obtained (Fig. 5). In addition, the identification was confirmed by sequence analyses. The region of mtDNA was amplified with primers C2F3 and 1108 (Powers and Harris 1993), cloned, sequenced (acc. no. OQ211107), and compared to other
spp. sequences from the Genbank. The determined sequence is 100% identical to an unidentified
sp. from Serbia, while the next highest scores are sequences of
from Slovenia, Greece and Iran, all of which have 99.94% sequence identity. In phylogenetic tree, all
sequences including the sequence from Serbia belong to a single clade. Egg masses isolated from infected tomato roots were used to establish a nematode culture in greenhouse and they caused typical root galls on cultivar Maraton of tomato. The galling index assessed 110 days-post-inoculation was in the range 4-5 according to the scoring scheme (1-10) for field evaluation of RKN infestations (Zeck 1971). To our knowledge, this is the first report of
in Serbia. The authors hypothesize that climate change and higher temperatures could lead to much greater spread and damage to various agricultural crops in the field by
in the future. National surveillance program for RKN in Serbia continued in 2022 and 2023. A management program to control the spread and damage from
will be implemented in Serbia in 2023. Acknowledgments: This work was financially supported by the Serbian Plant Protection Directorate of MAFWM in the frame of Program of Measures in Plant Health in 2021, the Slovenian Research Agency in the frame of Research Programme Agrobiodiversity (P4-0072) and the Ministry of Agriculture, Forestry and Food of the Republic of Slovenia in the frame of Expert work in the field of plant protection (C2337).
Satellite DNAs (satDNAs) are tandemly repeated non-coding DNA sequences that belong to the most abundant and the fastest evolving parts of the eukaryotic genome. A satellitome represents the ...collection of different satDNAs in a genome. Due to extreme diversity and methodological difficulties to characterize and compare satDNA collection in complex genomes, knowledge on their putative functional constraints and capacity to participate in genome evolution remains rather elusive. SatDNA transcripts have been detected in many species, however comparative studies of satDNA transcriptome between species are extremely rare. We conducted a genome-wide survey and comparative analyses of satellitomes among different closely related Meloidogyne spp. nematodes. The evolutionary trends of satDNAs suggest that each round of proposed polyploidization in the evolutionary history is concomitant with the addition of a new set of satDNAs in the satellitome of any particular Meloidogyne species. Successive incorporation of new sets of satDNAs in the genome along the process of polyploidization supports multiple hybridization events as the main factor responsible for the formation of these species. Through comparative analyses of 83 distinct satDNAs, we found a CENP-B box-like sequence motif conserved among 11 divergent satDNAs (similarity ranges from 36 to 74%). We also found satDNAs that harbor a splice leader (SL) sequence which, in spite of overall divergence, shows conservation across species in two putative functional regions, the 25-nt SL exon and the Sm binding site. Intra- and interspecific comparative expression analyses of the complete satDNA set in the analyzed Meloidogyne species revealed transcription profiles including a subset of 14 actively transcribed satDNAs. Among those, 9 show active transcription in every species where they are found in the genome and throughout developmental stages. Our results demonstrate the feasibility and power of comparative analysis of the non-coding repetitive genome for elucidation of the origin of species with a complex history. Although satDNAs generally evolve extremely quickly, the comparative analyses of 83 satDNAs detected in the analyzed Meloidogyne species revealed conserved sequence features in some satDNAs suggesting sequence evolution under selective pressure. SatDNAs that are actively transcribed in related genomes and throughout nematode development support the view that their expression is not stochastic.
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