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1681 - 1690 / 2000
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Too hot to handle : effects of water temperature on the early life stages of Gongolaria barbata (Fucales)
Ana Lokovšek, Valentina Pitacco, Annalisa Falace, Domen Trkov, Martina Orlando-Bonaca, 2024, original scientific article

Abstract: Gongolaria barbata plays a crucial role as a habitat-forming Fucales species in the Mediterranean Sea, thriving in shallow, sheltered coastal regions, where it exhibits optimal growth in a temperature range of 10 to 25 °C. In the northern Adriatic Sea, a semi-enclosed part of the Mediterranean, there has been a remarkable increase in seawater temperatures in recent decades, often exceeding 28 °C in summer. These high temperatures pose a significant threat to the vulnerable early life stages of G. barbata. This study delves into the effects of four temperatures (15, 18, 24, and 28 °C) on the growth of G. barbata over its first 16 days, closely monitoring mortality, deformities, and overall survival. Our experiments reveal that higher temperatures can result in deformities and increased mortality of germlings. Notably, a temperature of 28 °C resulted in the death of all germlings within the first week, whereas those exposed to 24 °C survived until the second week, albeit with significant deformities prior to death. In contrast, germlings cultivated at 15 and 18 °C exhibited normal development with minimal deformities. These results highlight the susceptibility of the early life stages of G. barbata to temperature-induced stress and provide valuable insights into the potential consequences of rising seawater temperatures in the Mediterranean.
Keywords: sea ​​temperature, early stages of growth, deformations, macroalgae, climate change, Mediterranean Sea
Published in DiRROS: 17.05.2024; Views: 474; Downloads: 444
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Two new species of Elaphoidella (Copepoda, Harpacticoida) from subterranean waters in Northeast Thailand, with a record of a gynandromorphic specimen and an up-to-date key to Elaphoidella species from Southeast Asia
Chaichat Boonyanusith, Anton Brancelj, La-orsri Sanoamuang, 2024, original scientific article

Abstract: Two new species of copepods of the genus Elaphoidella Chappuis, 1929 were discovered in a cave and a spring in northeastern Thailand. The first species, E. phuphamanensis sp. nov., belongs to species-group VII sensu Lang. It is most similar to E. turgisetosa Petkovski, 1980 in the armament of the male third exopod of the fourth swimming leg and the shape and armament of the fifth swimming leg in both sexes. However, it is easily distinguished from other congeners by the segmentation of the first swimming leg, the endopod of the fourth swimming leg, and the armature of the third exopod of swimming legs 2–4 in both sexes. The second species, E. propecabezasi sp. nov., is located in species-group I sensu Lang, where the male does not have a transformed seta on the third exopod of the fourth swimming leg and the female fifth swimming leg has four baseoendopodal robust setae, unequal in length. It is most similar to E. cabezasi Petkovski, 1982 and E. paraaffinis Watiroyram, Sanoamuang and Brancelj, 2017 in having the same armature formula as endopods 1–2 of female swimming legs 1–4. However, the ornamentation of the anal operculum, the shape of the caudal ramus, and the armature of the fifth swimming leg in both sexes distinguish them from each other. A rare gynandromorphic specimen of E. propecabezasi sp. nov. was recorded, and a revised key to Elaphoidella species in Southeast Asia is provided.
Keywords: cave-dwelling copepods, endemic distribution, groundwater habitats, intersex, morphology, zoology, Southeast Asia
Published in DiRROS: 17.05.2024; Views: 408; Downloads: 498
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1688.
Environmental factors influence cross-talk between a heat shock protein and an oxidative stress protein modification in the lizard Gallotia galloti
Edward Gilbert, Anamarija Žagar, Marta López-Darias, Rodrigo Megía-Palma, Karen A. Lister, Max Dolton Jones, Miguel A. Carretero, Nina Guerra Serén, Pedro Beltran-Alvarez, Katharina C. Wollenberg-Valero, 2024, original scientific article

Abstract: Better understanding how organisms respond to their abiotic environment, especially at the biochemical level, is critical in predicting population trajectories under climate change. In this study, we measured constitutive stress biomarkers and protein post-translational modifications associated with oxidative stress in Gallotia galloti, an insular lizard species inhabiting highly heterogeneous environments on Tenerife. Tenerife is a small volcanic island in a relatively isolated archipelago off the West coast of Africa. We found that expression of GRP94, a molecular chaperone protein, and levels of protein carbonylation, a marker of cellular stress, change across different environments, depending on solar radiation-related variables and topology. Here, we report in a wild animal population, cross-talk between the baseline levels of the heat shock protein-like GRP94 and oxidative damage (protein carbonylation), which are influenced by a range of available temperatures, quantified through modelled operative temperature. This suggests a dynamic trade-off between cellular homeostasis and oxidative damage in lizards adapted to this thermally and topologically heterogeneous environment.
Published in DiRROS: 17.05.2024; Views: 392; Downloads: 368
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1689.
Identification of epigenetically regulated genes involved in plant-virus interaction and their role in virus-triggered induced resistance
Régis L. Corrêa, Denis Kutnjak, Silvia Ambrós, Mónica Bustos, Santiago F. Elena, 2024, original scientific article

Abstract: Background: Plant responses to a wide range of stresses are known to be regulated by epigenetic mechanisms. Path-ogen-related investigations, particularly against RNA viruses, are however scarce. It has been demonstrated that Arabi-dopsis thaliana plants defective in some members of the RNA-directed DNA methylation (RdDM) or histone modi-fication pathways presented differential susceptibility to the turnip mosaic virus. In order to identify genes directly targeted by the RdDM-related RNA Polymerase V (POLV ) complex and the histone demethylase protein JUMONJI14 (JMJ14) during infection, the transcriptomes of infected mutant and control plants were obtained and integrated with available chromatin occupancy data for various epigenetic proteins and marks. Results: A comprehensive list of virus-responsive gene candidates to be regulated by the two proteins was obtained. Twelve genes were selected for further characterization, confirming their dynamic regulation during the course of infection. Several epigenetic marks on their promoter sequences were found using in silico data, raising confidence that the identified genes are actually regulated by epigenetic mechanisms. The altered expression of six of these genes in mutants of the methyltransferase gene CURLY LEAF and the histone deacetylase gene HISTONE DEACETYLASE 19 suggests that some virus-responsive genes may be regulated by multiple coordinated epigenetic complexes. A temporally separated multiple plant virus infection experiment in which plants were transiently infected with one virus and then infected by a second one was designed to investigate the possible roles of the identified POLV- and JMJ14-regulated genes in wild-type (WT ) plants. Plants that had previously been stimulated with viruses were found to be more resistant to subsequent virus challenge than control plants. Several POLV- and JMJ14-regulated genes were found to be regulated in virus induced resistance in WT plants, with some of them poisoned to be expressed in early infection stages. Conclusions: A set of confident candidate genes directly regulated by the POLV and JMJ14 proteins during virus infection was identified, with indications that some of them may be regulated by multiple epigenetic modules. A sub-set of these genes may also play a role in the tolerance of WT plants to repeated, intermittent virus infections.Keywords Biotic stress, Defense priming, Epigenetics, Histone modifications, Induced resistance, Potyvirus, RNA-directed DNA methylation.
Keywords: biotic stress, defense priming, epigenetics, histone modifications, induced resistance, Potyvirus, RNA-directed DNA methylation
Published in DiRROS: 17.05.2024; Views: 479; Downloads: 1015
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1690.
First report of collar and root rot of lettuce caused by Plectosphaerella cucumerina in Serbia
Milica Mihajlović, Jovana Hrustić, Ana Vučurović, Mila Grahovac, Dragana Budakov, Tatjana Dudaš, Brankica Pešić, 2024, other scientific articles

Abstract: In March 2021, unusual plant stuning, collar, and wet root rot of lettuce (Lactuca sativa L.) during the rosette stage was observed in two commercial fields in Serbia (44°58'N, 20°32'E; 44°45'N, 20°43'E). Disease incidence in the fields (≈ 0.9 ha each) was approximately 15 and 20%, respectively. Initial above-ground symptoms were yellowing and wilting of leaves, while below-ground symptoms were collar, wet root rot, and lesions becoming necrotic. Eventually, whole plants wilted, collapsed, and died. A total of 35 symptomatic plants were collected from the fields, and diseased tissues were cut into small pieces, surface sterilized, and plated on potato dextrose agar (PDA). Isolation resulted in 20 morphologically uniform monoconidial isolates. The isolates formed white to creamy colonies, gradually becoming salmon pink, slimy, or moist in appearance, with sparse aerial mycelia. Numerous hyphal coils with conidiophores and hyaline, smooth-surfaced, ellipsoid to ovoid, septate or aseptate conidia were formed (4.5 to 10.1×1.2 to 3.7 μm (n = 100)). To confirm the species identity, the internal transcribed spacer (ITS) region and the D1/D2 region of a selected representative isolate 13-3-c were amplified and sequenced by using primer pairs ITS1/ITS4 (White et al. 1990) and N1/N2 (O’Donnell and Gray 1995), respectively. The sequences were deposited in GenBank (ITS: OR880564 and D1/D2: OR880567). Sequence analysis revealed 100% nucleotide identity with P. cucumerina isolates from different countries deposited in the NCBI GenBank, including isolate MH860704 (Vu et al. 2019) (ITS region) and isolate KY662256 (Su et al. 2017) (D1/D2 region). Neighbor-joining analysis was conducted based on the combined ITS and D1/D2 regions, and the tree was constructed with the substitution models (1,000 bootstrap). The combined phylogeny confirmed that the sequences shared a common clade with P. cucumerina. Hence, morphological, microscopic, and molecular characterization confirmed the pathogen as P. cucumerina (Palm et al., 1995; Carlucci et al., 2012). In a pathogenicity assay, 10 isolates were tested. Five 30-day-old lettuce plants (cv. Majska Kraljica) per isolate were root-dipped in the conidial suspensions (1×105 conidia/ml). The 10 inoculated plants were transplanted into 1 L pots containing sterile substrate (Floragard, Germany). Plants treated with sterile distilled water were used as controls. Plants were maintained in a greenhouse at 25 to 28°C under a 12-hour photoperiod (Cai et al., 2021). Four weeks after inoculation, stunting, chlorosis, and wilting of plants were observed, while collars and roots exhibited typical decaying symptoms. No symptoms were observed on the control plants. The pathogen was reisolated from symptomatic tissue as previously described. Koch's postulates were completed by confirming the identity of reisolates based on morphological features. To our knowledge, this is the first report of P. cucumerina on lettuce or any other crop in Serbia. P. cucumerina is already known as a pathogen of lettuce and other hosts grown in many countries worldwide, as well as in some European countries (Belgium, England, Italy, the Netherlands, and Switzerland) (Zhang et al. 2019). This emerging pathogen may cause significant economic losses in lettuce production in Serbia and in the entire Balkan region. Our results may help to develop effective management strategies based on accurate and timely identification and regular pathogen monitoring.
Keywords: detection, identification, salat, plant diseases
Published in DiRROS: 17.05.2024; Views: 382; Downloads: 153
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