1. Insertion of a specific fungal 3'-phosphoadenosine-5'-phosphatase motif into a plant homologue improves halotoleranceand drought tolerance of plantsMeti Buh Gašparič, Metka Lenassi, Cene Gostinčar, Ana Rotter, Ana Plemenitaš, Nina Gunde-Cimerman, Kristina Gruden, Jana Žel, 2013, izvirni znanstveni članek Povzetek: Soil salinity and drought are among the most serious agricultural and environmental problems of today. Therefore, investigations of plant resistance to abiotic stress have received a lot of attention in recent years. In this study, we identified the complete coding sequence of a 3′-phosphoadenosine-5′-phosphatase protein, ApHal2, from the halotolerant yeast Aureobasidium pullulans. Expression of the ApHAL2 gene in a Saccharomyces cerevisiae hal2 mutant complemented the mutant auxotrophy for methionine, and rescued the growth of the hal2 mutant in media with high NaCl concentrations. A 21-amino-acids-long region of the ApHal2 enzyme was inserted into the Arabidopsis thaliana homologue of Hal2, the SAL1 phosphatase. The inserted sequence included the META motif, which has previously been implicated in increased sodium tolerance of the Hal2 homologue from a related fungal species. Transgenic Arabidopsis plants overexpressing this modified SAL1 (mSAL1) showed improved halotolerance and drought tolerance. In a medium with an elevated salt concentration, mSAL1-expressing plants were twice as likely to have roots in a higher length category in comparison with the wild-type Arabidopsis and with plants overexpressing the native SAL1, and had 5% to 10% larger leaf surface area under moderate and severe salt stress, respectively. Similarly, after moderate drought exposure, the mSAL1-expressing plants showed 14% increased dry weight after revitalisation, with no increase in dry weight of the wild-type plants. With severe drought, plants overexpressing native SAL1 had the worst rehydration success, consistent with the recently proposed role of SAL1 in severe drought. This was not observed for plants expressing mSAL1. Therefore, the presence of this fungal META motif sequence is beneficial under conditions of increased salinity and moderate drought, and shows no drawbacks for plant survival under severe drought. This demonstrates that adaptations of extremotolerant fungi should be considered as a valuable resource for improving stress-tolerance in plant breeding in the future. Ključne besede: soil salinity and drought, plant resistance, abiotic stress Objavljeno v DiRROS: 02.08.2024; Ogledov: 258; Prenosov: 224 Celotno besedilo (7,12 MB) Gradivo ima več datotek! Več... |
2. Stable isotope composition in tree rings of Fagus sylvatica L. saplings reflects environmental variation induced by silviculture and microsite factorsJanez Kermavnar, Tom Levanič, Lado Kutnar, 2023, izvirni znanstveni članek Povzetek: Natural regeneration of tree species is sensitive to silvicultural interventions. This study aimed to investigate the effects of different cutting intensities and local topographic and soil conditions on the composition of stable carbon (δ13C) and oxygen (δ18O) isotopes in wood of young beech (Fagus sylvatica L.) trees. Beech saplings in the regeneration layer were sampled in summer 2018 at three study sites in Dinaric fir-beech forests in the karst area of Slovenia. Three different cutting intensities were performed in 2012: i) no cutting (control), ii) 50% cutting of the stand’s growing stock creating thinned stands, and iii) 100% cutting of the stand’s growing stock creating 0.4 ha canopy gaps. We show that δ13C increased along the gradient of cutting intensity. On average, δ13C values in the tree rings were ∼ 2‰ increased in trees from canopy gaps than from closed control stands. Furthermore, δ13C was higher on south-facing slopes characterized by higher air temperatures and lower relative humidity compared to north-facing slopes of karst sinkholes. Additionally, the results suggest a dependence of δ18O on interannual and cross-site climatic variations, particularly in the case of summer precipitation amount. δ18O also responded to soil depth, with beech individuals exhibiting lower values on deeper soils, presumably characterized by higher soil water availability compared to shallow soils. The results are discussed in the context of future climate change, as many beech-dominated forests on karst terrain in the Dinaric Mountains are particularly affected by climate warming and drying due to prolonged and reoccurring summer droughts, intensified large-scale disturbances, and often shallow soils with low water storage capacity. Ključne besede: stable carbon isotopes, stable oxygen isotopes, tree cutting, microclimate, drought stress, dinaric fir-beech forests Objavljeno v DiRROS: 05.04.2023; Ogledov: 1182; Prenosov: 433 Celotno besedilo (2,95 MB) Gradivo ima več datotek! Več... |
3. Repository of drought event impacts across the danube catchment countries between 1981 and 2016 using publicly available sourcesJiří Jakubínský, Monika Bláhová, Lenka Bartošová, Klára Steinerová, Jan Balek, Petra Dížková, Daniela Semerádová, Daniel Alexandru, Galia Bardarska, Sabina Bokal, Gregor Gregorič, Gal Oblišar, Andreja Sušnik, 2019, izvirni znanstveni članek Povzetek: Drought directly and indirectly affects human society in a number of ways. In many regions of the world climate change will exasperate the effects of droughts, affect national economies more intensely. The main aim of this article was to catalogue and analyze the drought impacts in the 11 Central and South Eastern European states located in the Danube river basin. The identification of dry episodes was based on information from publicly available sources, namely, newspaper and journal articles that reported drought impacts. Information on drought impact occurrences was classified into one of five defined categories in which the drought impact report was most clearly manifested (i.e., agriculture, forestry, soil systems, wildfires and hydrology). In terms of the spatial distribution of drought impacts, individual recorded events were analyzed at the level of EU NUTS regions (or their equivalent in non-EU countries). The analysis highlights country-specific vulnerability to drought. Furthermore, gradual increases in drought events and the number of reported impacts were identified, which was particularly evident in the agricultural sector. Ključne besede: drought impact, Danube basin, agriculture, climate change, water stress Objavljeno v DiRROS: 21.04.2022; Ogledov: 1213; Prenosov: 525 Celotno besedilo (2,24 MB) Gradivo ima več datotek! Več... |
4. Surprising drought tolerance of Fir (Abies) species between past climatic adaptation and future projections reveals new chances for adaptive forest managementCsaba Mátyás, František Beran, Jaroslav Dostál, Jiří Čáp, Martin Fulín, Monika Vejpustková, Gregor Božič, Pál Balázs, Josef Frýdl, 2021, izvirni znanstveni članek Povzetek: esearch Highlights: Data of advanced-age provenance tests were reanalyzed applying a new approach, to directly estimate the growth of populations at their original sites under individually generated future climates. The results revealed the high resilience potential of fir species. Background and Objectives: The growth and survival of silver fir under future climatic scenarios are insufficiently investigated at the xeric limits. The selective signature of past climate determining the current and projected growth was investigated to analyze the prospects of adaptive silviculture and assisted transfer of silver fir populations, and the introduction of non-autochthonous species. Materials and Methods: Hargreaves% climatic moisture deficit was selected to model height responses of adult populations. Climatic transfer distance was used to assess the relative drought stress of populations at the test site, relating these to the past conditions to which the populations had adapted. ClimateEU and ClimateWNA pathway RCP8.5 data served to determine individually past, current, and future moisture deficit conditions. Besides silver fir, other fir species from South Europe and the American Northwest were also tested. Results: Drought tolerance profiles explained the responses of transferred provenances and predicted their future performance and survival. Silver fir displayed significant within-species differentiation regarding drought stress response. Applying the assumed drought tolerance limit of 100 mm relative moisture deficit, most of the tested silver fir populations seem to survive their projected climate at their origin until the end of the century. Survival is likely also for transferred Balkan fir species and for grand fir populations, but not for the Mediterranean species. Conclusions: The projections are less dramatic than provided by usual inventory assessments, considering also the resilience of populations. The method fills the existing gap between experimentally determined adaptive response and the predictions needed for management decisions. It also underscores the unique potential of provenance tests. Ključne besede: climate change, common garden, provenance test, silver fir, grand fir, Balkan firs, drought stress, resilience, climate transfer distance, adaptation Objavljeno v DiRROS: 05.07.2021; Ogledov: 1238; Prenosov: 750 Celotno besedilo (1,46 MB) Gradivo ima več datotek! Več... |
5. Drought stress can induce the pathogenicity of Cryptostroma corticale, the causal agent of sooty bark disease of sycamore mapleNikica Ogris, Ana Brglez, Barbara Piškur, 2021, izvirni znanstveni članek Povzetek: Reports of sooty bark disease of maples caused by the fungus Cryptostroma corticale have recently been emerging from across Europe. The aims of our study were to describe the first report of sooty bark disease in Slovenia, to determine the pathogenicity of C. corticale, to confirm the optimum temperature for the growth of the fungus, and to determine the mass loss of Acer pseudoplatanus wood inoculated by C. corticale. We confirmed the presence of C. corticale on A. pseudoplatanus via morphological and molecular analysis. The optimal growth of C. corticale was measured in vitro on potato dextrose agar and was determined to occur at 25 °C. Pathogenicity tests were performed on 30 saplings of A. pseudoplatanus under two treatments, humid and drought stress, and the fungus was pathogenic in both treatments. The mean length of bark lesions and wood discoloration of the drought-stressed saplings was significantly greater than that in the humid treatment. Re-isolations of C. corticale were successful from all inoculated saplings, and thus Koch%s postulates were confirmed. The mass loss of A. pseudoplatanus wood was determined by mini-block test in a period of 10 weeks and was observed as minimal. Based on the results, we conclude that C. corticale is a weak and opportunistic pathogen that most likely expresses itself intensively under hot and dry conditions. Ključne besede: pathogenicity, drought stress, optimal growth, climate change, mass loss, mini-block test, wood rot, opportunistic pathogen, saprophyte, endophyte Objavljeno v DiRROS: 23.03.2021; Ogledov: 1408; Prenosov: 1065 Celotno besedilo (3,21 MB) Gradivo ima več datotek! Več... |
6. Discrimination between abiotic and biotic drought stress in tomatoes using hyperspectral imagingNik Susič, Uroš Žibrat, Saša Širca, Polona Strajnar, Jaka Razinger, Matej Knapič, Andrej Vončina, Gregor Urek, Barbara Gerič Stare, izvirni znanstveni članek Povzetek: Crop plants are subjected to various biotic and abiotic stresses. Both root-knot nematodes (biotic stress) and water deficiency (abiotic stress) lead to similar drought symptoms in the plant canopy. In this work, hyperspectral imaging was used for early detection of nematode infestation and water deficiency (drought) stress in tomato plants. Hyperspectral data in the range from 400 to 2500 nm of plants subjected to different watering regimes and nematode infestation levels were analysed by partial least squares – discriminant analysis (PLS-DA) and partial least squares – support vector machine (PLS-SVM) classification. PLS-SVM classification achieved up to 100% accuracy differentiating between well-watered and water-deficient plants, and between 90 and 100% when identifying nematode-infested plants. Grouping the data according to the time of imaging increased the accuracy of classification. Shortwave infrared spectral regions associated with the OH and CH stretches were most relevant for the identification of nematode infested plants and severity of infestation. This study demonstrates the capability of hyperspectral imaging to identify and discriminate between biotic and abiotic plant stresses. Ključne besede: nematode, Hyperspectral imaging, Drought stress, Root-knot nematode, Tomato Objavljeno v DiRROS: 20.07.2018; Ogledov: 4259; Prenosov: 2654 Celotno besedilo (847,87 KB) Gradivo ima več datotek! Več... |