Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Authors
Aritz Royo-Esnal Andrea Onofri Donato Loddo Jevgenija Necajeva Peter K. Jensen Garifalia Economou Alireza Taab Agnieszka Synowiec Isabel M. Calha Lars Andersson Ahmet Uludag Ilhan Uremis Alistair J. Murdoch Kirsten TørresenAbstract
Echinochloa crus-galli (L.) P. Beauv. is one of the most important weeds. It is distributed worldwide and has adapted to diverse habitats and climatic conditions. This study aimed to compare the emergence patterns of two populations of E. crus-galli from different environments at 11 locations across Europe and the Middle East. Seeds of the two populations were collected from maize in Italy and from spring barley in Norway and were then buried in soil in autumn 2015. In the spring of 2016, the soil was disturbed around the usual seedbed preparation date in each location and emergence was recorded. The soil was again disturbed a year later and emergence was recorded for a second season. Total emergence, the times of onset, end and to 50% emergence and the period between 25% and 75% of emergence were analysed by two-way ANOVA and principal components analysis. The Italian population showed a higher emergence than the Norwegian population in Southern locations, while the ranking was reversed in Northern locations. In almost all locations, a tendency to emerge earlier was recorded for the Norwegian population, but the periods from 25% to 75% emergence were similar for both populations. Total emergence, and the times of onset and end of emergence seemed to be mainly under genotypic (plus maternal) control, suggesting there were different temperature thresholds for seedling emergence in each population. Conversely, the duration of emergence seemed to be mainly under environmental control. This research confirms the high variability between populations and suggests the need to continue identifying key characteristics for the development of efficient models for seedling emergence in specific climates and/or latitudes.
Abstract
Elymus repens (L.) Gould), Cirsium arvense (L.) Scop. and Sonchus arvensis L. are important arable creeping perennial weeds in Europe. These are clonal plants with subterranean reproductive organs (E. repens, rhizomes, the two dicots, horizontal creeping roots) sprouting from ramets. We tested the sprouting ability and early growth of ramet sprouts at temperatures typical for Nordic autumn climate and with different preconditions of the mother plant (time in autumn, mother plant age, climate change experiences of the mother plants (two experiments)). The species reacted differently, with S. arvensis not sprouting at all, and C. arvense ramets sprouting at higher temperatures than those of E. repens, which sprouted at all tested temperatures. Plant age affected only the ramet sprout biomass of E. repens. Climate change during mother plant growth only affected C. arvense, with the highest above-ground biomass of the sprouted ramets at an elevated temperature and ambient CO2. Testing earlier in autumn showed more sprouting and biomass for C. arvense and E. repens than testing later in the season. The observed temperature responses confirmed more and bigger sprouts with higher autumn temperatures. Controlling the sprouted ramets in autumn is easier for E. repens than for C. arvensis. Due to their low/no sprouting ability in autumn, the ramets of S. arvensis cannot be controlled in autumn.
Authors
Jevgenija Necajeva Aritz Royo-Esnal Donato Loddo Peter Jensen Alireza Taab Agnieszka Synowiec Ahmet Uludag Ilhan Uremis Alistair Murdoch Anna Bochenek Andrea Onofri Kirsten TørresenAbstract
Barnyard grass [Echinochloa crus-galli (L.) Beauv] is a competitive C4 weed species that is widely distributed throughout the world. Although it originated in warm climatic conditions, currently, it is found in Europe as far north as Norway. This study aimed to compare the phenological development of plants from different climatic conditions in varying environmental conditions. To represent the contrasting climatic conditions within Europe, seeds were collected in Norway and Italy, and distributed to the study participants, to be sown at 10 different sites as two common populations. In addition to that, seeds of two to three local populations were collected near each of the sites. The development of the plants was monitored in a pot experiment set up under field conditions. The time to reach heading in the first year of the experiment was 77.6% faster (ranging from 45.9 to 98.3% on average) in the Norwegian than in the Italian population. However, in the leaf development stage, the difference between the common populations was smaller by, 23.5% on average (0–46.7%) and was mostly not significant. Our results indicate that different E. crus-galli ecotypes, characterized by differences in their phenological development, evolved within the distribution area of this species in Europe. However, the early development of the plants progressed with negligible differences between populations. The findings reported here can be used to adapt existing models from one region to regions with different climatic conditions for use in decision support systems and for research into plant population dynamics.
Abstract
Book of Abstracts p. 225: Perennial sow-thistle (Sonchus arvensis L.) is a problematic weed in arable crops in northern Europe. To control S. arvensis, strategies which reduce both seeds and creeping root production are essential. Inducing repeated sprouting should result in depleting root reserves and reduction in the subsequent shoot emergence. Earlier studies of S. arvensis in the northern European countries have shown a restricted sprouting ability from July/August/ September to October/November. To better understand the sprouting patterns, we conducted joint outdoor pot experiments from March 2020 until July 2021 in three northern European regions: Northern Germany, Norway, and Finland. In each pot, root pieces of 5 cm from local plant material were planted at 5cm depth. Above-ground plants were cut at the soil surface in the growing season of 2020 at 1) flower-bud stage, 2) first visible open flowers, 3) start of seed production, and 4) withering stage. Shoots were counted monthly in 2020 and 2021. In the year 2020, in Germany, sprouting, flowering, seed-set, and withering started earlier than at the other two sites. Significantly more shoots showed up at the flower-bud stage in Germany and Finland compared to Norway. In Finland, significantly more shoots were observed at the later cutting stages compared to the first counts at the flower bud stage. As a subsequent effect, fewest shoots showed up in 2021 at the German and Finnish sites after cutting at flower bud and early flowering stage. The lowest emerged shoot number in 2021 for Norway tended to occur after cutting at the flower bud stage and the start of seed production. Accordingly, cutting at the flower-bud stage decreases the ability to produce shoots in the next year. Keywords: Perennial sow-thistle, sprouting, cutting, shoots Acknowledgements: This research was part of the project “AC/DC-weeds” which is funded by ERA-Net Cofund SusCrop/EU Horizon 2020, Grant no. 771134
Authors
Andre van Eerde Aniko Varnai Yanliang Wang Lisa Paruch John-Kristian Jameson Fen Qiao Hans Geir Eiken Hang Su Vincent Eijsink Jihong Liu ClarkeAbstract
Giant panda could have bamboo as their exclusive diet for about 2 million years because of the contribution of numerous enzymes produced by their gut bacteria, for instance laccases. Laccases are blue multi-copper oxidases that catalyze the oxidation of a broad spectrum of phenolic and aromatic compounds with water as the only byproduct. As a “green enzyme,” laccases have potential in industrial applications, for example, when dealing with degradation of recalcitrant biopolymers, such as lignin. In the current study, a bacterial laccase, Lac51, originating from Pseudomonas putida and identified in the gut microbiome of the giant panda’s gut was transiently expressed in the non-food plant Nicotiana benthamiana and characterized. Our results show that recombinant Lac51 exhibits bacterial laccase properties, with optimal pH and temperature at 7–8 and 40°C, respectively, when using syringaldazine as substrate. Moreover, we demonstrate the functional capability of the plant expressed Lac51 to oxidize lignin using selected lignin monomers that serve as substrates of Lac51. In summary, our study demonstrates the potential of green and non-food plants as a viable enzyme production platform for bacterial laccases. This result enriches our understanding of plant-made enzymes, as, to our knowledge, Lac51 is the first functional recombinant laccase produced in plants.
Authors
Philipp Lehmann Tea Ammunet Madeleine Barton Andrea Battisti Sanford D. Eigenbrode Jane Uhd Jepsen Gregor Kalinkat Seppo Neuvonen Pekka Niemelä John s. Terblanche Bjørn Økland Christer BjörkmanAbstract
Although it is well known that insects are sensitive to temperature, how they will be affected by ongoing global warming remains uncertain because these responses are multifaceted and ecologically complex. We reviewed the effects of climate warming on 31 globally important phytophagous insect pests to determine whether general trends in their responses to warming were detectable. We included four response categories (range expansion, life history, population dynamics, and trophic interactions) in this assessment (Figure 1). For the majority of these species, we identified at least one response to warming that affects the severity of the threat they pose as pests. Among these insect species, 41% showed responses expected to lead to increased pest damage, whereas only 4% exhibited responses consistent with reduced effects; notably, most of these species (55%) demonstrated mixed responses. This means that the severity of a given insect pest may both increase and decrease with ongoing climate warming. Overall, our analysis indicated that anticipating the effects of climate warming on phytophagous insect pests is far from straightforward. Rather, efforts to mitigate the undesirable effects of warming on insect pests must include a better understanding of how individual species will respond, and the complex ecological mechanisms underlying their responses. Although not the focus of our review, the main conclusions we reach also should hold true for biological control agents and there is indeed evidence for phenological mismatch and other climate-change-related effects on biological control of varying magnitude among systems. At least some natural control agents seem to respond more positively to climate warming than their herbivore prey, and as such, one might expect better biological control in certain systems. One potential reason for these differences is that while both control agents and herbivores are affected physiologically by changing climate drivers, by for instance increasing development rate, the control agents in addition are affected behaviourally and, for instance, can increase foraging or searching rate. In addition, and specifically in relation to biological control, it is often crucial to achieve high synchronization between control agent and prey, which can be complicated by different response rates to winter temperature. This is something that has been observed with the chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae) and its parasitoid Proceedings of ISBCA 6 – D.C. Weber, T.D. Gariepy, and W.R. Morrison III, eds. (2022) page 3.19 Torymus sinensis (Hymenoptera: Torymidae) over the last years, as the gall wasp depends largely on the budbreak of the host plant while the parasitoid relies mainly on the air temperature for spring emergence. Figure 1. Four major categories of responses to climate warming. (a) Range changes include range expansions or shifts (latitudinal and/or altitudinal). (b) Life-history changes primarily consist of alterations to biological timing events or the number of annual generations. (c) Population dynamics reflect population size, and damage is expected to increase whenever temperature limits performance, but if threshold temperatures are reached, control and related feedback mechanisms may be triggered. Tpresent reflects current temperatures over a time period (e.g., a year or a day), whereas Tfuture reflects future temperatures over the same period. (d) Trophic interactions reflect temperature responses of organisms and trophic groups (plants = dashed green line, herbivores = solid red line, predators = dashed blue line). Because vital rates (i.e. rates of important life-history traits, such as growth, dispersal, and reproduction) may vary, climate warming could strongly affect trophic relationships. This is of direct consequence for the planning and efficiency of biological control programs.
Authors
Paal KrokeneAbstract
No abstract has been registered
Abstract
Tree-killing bark beetles in conifer forests vector symbiotic fungi that are thought to help the beetles kill trees. Fungal symbionts emit diverse volatile blends that include bark beetle semiochemicals involved in mating and host localization. In this study, all 12 tested fungal isolates emitted beetle semiochemicals when growing in medium amended with linoleic acid. These semiochemicals included the spiroacetals chalcogran, trans-conophthorin and exo-brevicomin, as well as 2-methyl-3-buten-1-ol, the main aggregation pheromone component of the spruce bark beetle Ips typographus. The emission of these compounds was affected by the type of fatty acid present (linoleic vs. oleic acid). Accumulating evidence shows that the fatty acid composition in conifer bark can facilitate colonization by bark beetles and symbiotic fungi, whereas the fatty acid composition of non-host trees can be detrimental for beetle larvae or fungi. We hypothesize that beetles probe the fatty acid composition of potential host trees to test their suitability for beetle development and release of semiochemicals by symbiotic fungi.
Authors
Petter Öhrn Mats Berlin Jan-Olov Weslien Malin Elfstrand Audrius Menkis Paal Krokene Anna Maria JönssonAbstract
No abstract has been registered
Authors
Jorunn BørveAbstract
No abstract has been registered