| 1. |
- Edwards, Kieron D., et al.
(författare)
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Circadian clock components control daily growth activities by modulating cytokinin levels and cell division-associated gene expression in Populus trees
- 2018
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Ingår i: Plant, Cell and Environment. - : John Wiley & Sons. - 0140-7791 .- 1365-3040. ; 41:6, s. 1468-1482
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Tidskriftsartikel (refereegranskat)abstract
- Trees are carbon dioxide sinks and major producers of terrestrial biomass with distinct seasonal growth patterns. Circadian clocks enable the coordination of physiological and biochemical temporal activities, optimally regulating multiple traits including growth. To dissect the clock's role in growth, we analysed Populus tremula x P. tremuloides trees with impaired clock function due to down-regulation of central clock components. late elongated hypocotyl (lhy-10) trees, in which expression of LHY1 and LHY2 is reduced by RNAi, have a short free-running period and show disrupted temporal regulation of gene expression and reduced growth, producing 30-40% less biomass than wild-type trees. Genes important in growth regulation were expressed with an earlier phase in lhy-10, and CYCLIN D3 expression was misaligned and arrhythmic. Levels of cytokinins were lower in lhy-10 trees, which also showed a change in the time of peak expression of genes associated with cell division and growth. However, auxin levels were not altered in lhy-10 trees, and the size of the lignification zone in the stem showed a relative increase. The reduced growth rate and anatomical features of lhy-10 trees were mainly caused by misregulation of cell division, which may have resulted from impaired clock function.
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| 2. |
- Fegraeus, Kim, et al.
(författare)
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An endothelial regulatory module links blood pressure regulation with elite athletic performance
- 2024
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 20:6
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Tidskriftsartikel (refereegranskat)abstract
- The control of transcription is crucial for homeostasis in mammals. A previous selective sweep analysis of horse racing performance revealed a 19.6 kb candidate regulatory region 50 kb downstream of the Endothelin3 (EDN3) gene. Here, the region was narrowed to a 5.5 kb span of 14 SNVs, with elite and sub-elite haplotypes analyzed for association to racing performance, blood pressure and plasma levels of EDN3 in Coldblooded trotters and Standardbreds. Comparative analysis of human HiCap data identified the span as an enhancer cluster active in endothelial cells, interacting with genes relevant to blood pressure regulation. Coldblooded trotters with the sub-elite haplotype had significantly higher blood pressure compared to horses with the elite performing haplotype during exercise. Alleles within the elite haplotype were part of the standing variation in pre-domestication horses, and have risen in frequency during the era of breed development and selection. These results advance our understanding of the molecular genetics of athletic performance and vascular traits in both horses and humans.
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| 3. |
- Ibáñez, Cristian, et al.
(författare)
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Circadian clock components regulate entry and affect exit of seasonal dormancy as well as winter hardiness in Populus trees
- 2010
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Ingår i: Plant Physiology. - : ASPB Publications. - 0032-0889 .- 1532-2548. ; 153:4, s. 1823-1833
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Tidskriftsartikel (refereegranskat)abstract
- This study addresses the role of the circadian clock in the seasonal growth cycle of trees: growth cessation, bud set, freezing tolerance, and bud burst. Populus tremula x Populus tremuloides (Ptt) LATE ELONGATED HYPOCOTYL1 (PttLHY1), PttLHY2, and TIMING OF CAB EXPRESSION1 constitute regulatory clock components because down-regulation by RNA interference of these genes leads to altered phase and period of clock-controlled gene expression as compared to the wild type. Also, both RNA interference lines show about 1-h-shorter critical daylength for growth cessation as compared to the wild type, extending their period of growth. During winter dormancy, when the diurnal variation in clock gene expression stops altogether, down-regulation of PttLHY1 and PttLHY2 expression compromises freezing tolerance and the expression of C-REPEAT BINDING FACTOR1, suggesting a role of these genes in cold hardiness. Moreover, down-regulation of PttLHY1 and PttLHY2 causes a delay in bud burst. This evidence shows that in addition to a role in daylength-controlled processes, PttLHY plays a role in the temperature-dependent processes of dormancy in Populus such as cold hardiness and bud burst.
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| 4. |
- Jurca, Manuela, et al.
(författare)
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ZEITLUPE Promotes ABA-Induced Stomatal Closure in Arabidopsis and Populus
- 2022
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Ingår i: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Plants balance water availability with gas exchange and photosynthesis by controlling stomatal aperture. This control is regulated in part by the circadian clock, but it remains unclear how signalling pathways of daily rhythms are integrated into stress responses. The serine/threonine protein kinase OPEN STOMATA 1 (OST1) contributes to the regulation of stomatal closure via activation of S-type anion channels. OST1 also mediates gene regulation in response to ABA/drought stress. We show that ZEITLUPE (ZTL), a blue light photoreceptor and clock component, also regulates ABA-induced stomatal closure in Arabidopsis thaliana, establishing a link between clock and ABA-signalling pathways. ZTL sustains expression of OST1 and ABA-signalling genes. Stomatal closure in response to ABA is reduced in ztl mutants, which maintain wider stomatal apertures and show higher rates of gas exchange and water loss than wild-type plants. Detached rosette leaf assays revealed a stronger water loss phenotype in ztl-3, ost1-3 double mutants, indicating that ZTL and OST1 contributed synergistically to the control of stomatal aperture. Experimental studies of Populus sp., revealed that ZTL regulated the circadian clock and stomata, indicating ZTL function was similar in these trees and Arabidopsis. PSEUDO-RESPONSE REGULATOR 5 (PRR5), a known target of ZTL, affects ABA-induced responses, including stomatal regulation. Like ZTL, PRR5 interacted physically with OST1 and contributed to the integration of ABA responses with circadian clock signalling. This suggests a novel mechanism whereby the PRR proteins—which are expressed from dawn to dusk—interact with OST1 to mediate ABA-dependent plant responses to reduce water loss in time of stress.
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| 5. |
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| 6. |
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| 7. |
- Kozarewa, Iwanka, et al.
(författare)
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Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus
- 2010
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Ingår i: Plant Molecular Biology. - : Springer Science and Business Media LLC. - 0167-4412 .- 1573-5028. ; 73:1-2, s. 143-56
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Tidskriftsartikel (refereegranskat)abstract
- In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.
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| 8. |
- Molander, Mikael, et al.
(författare)
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p-Mentha-1,3-dien-9-ol: A novel aggregation-sex pheromone for monitoring longhorn beetles (Cerambycidae) in Eurasia and North America
- 2022
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Ingår i: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 146, s. 1098-1108
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Tidskriftsartikel (refereegranskat)abstract
- Longhorn beetles (Cerambycidae) are a diverse family of beetles that can cause considerable damage as forest pests and vectors of pathogens, as well as being important components of forest food webs and ecosystem functionality. In recent years, numerous cerambycid pheromones have been identified, revealing some broad general patterns in functionality in terms of sex or aggregation-sex pheromones in different subfamilies and different types of compounds characterizing the pheromones of various cerambycid taxa. Here, we describe the identification of the aggregation-sex pheromones of the Eurasian longhorn beetle Aromia moschata moschata (L.) (Cerambycinae; tribe Callichromatini) and the North American species Holopleura marginata LeConte (Cerambycinae; Holopleurini), as part of an ongoing effort to extend the taxonomic coverage of identified cerambycid pheromones and to expand the prospects for cerambycid monitoring into the study of biodiversity and ecosystem services. Both species were found to use the novel pheromone compound p-mentha-1,3-dien-9-ol, which also attracted significant numbers of the longhorn beetle Xestoleptura crassipes (LeConte) (Lepturinae; Lepturini) in trials in California. p-Mentha-1,3-dien-9-ol represents a class of pheromone compounds novel to both tribes (Callichromatini and Holopleurini), further increasing the chemical space of identified pheromones within the subfamily Cerambycinae. This compound is also noteworthy because it represents an entirely different chemical class of pheromones than the monoepoxide (E)-2-cis-6,7-epoxynonenal, previously reported as an aggregation-sex pheromone for the invasive Asian congener Aromia bungii (Faldermann).
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| 9. |
- Molander, Mikael, et al.
(författare)
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The aggregation-sex pheromones of the cerambycid beetles Anaglyptus mysticus and Xylotrechus antilope ssp. antilope: new model species for insect conservation through pheromone-based monitoring
- 2019
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Ingår i: Chemoecology. - : Springer Science and Business Media LLC. - 0937-7409 .- 1423-0445. ; 29, s. 111-124
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Tidskriftsartikel (refereegranskat)abstract
- We studied the pheromone chemistry of the cerambycids Anaglyptus mysticus and Xylotrechus antilope ssp. antilope with the goal of identifying attractants that could be used as tools for pheromone-based monitoring of these two species, which are rare and red-listed in parts of northern Europe. Beetles were reared from naturally colonized branches of hazel (Corylus avellana) or oak (Quercusrobur), respectively, and used for headspace sampling. The extracts of volatiles were analyzed by gas chromatography-mass spectrometry. Males of A. mysticus consistently produced large quantities of (R)-3-hydroxy-2-hexanone and 2-nonanone, minor amounts of 2,3-hexanedione, and trace amounts of six other compounds. The average proportion of 2-nonanone to (R)-3-hydroxy-2-hexanone was 70:100. Males of X. antilope produced large quantities of (S)-2-hydroxy-3-octanone, and minor quantities of 2,3-octanedione. None of these compounds were present in the corresponding extracts of females from either species. The attractiveness of the dominant compounds produced by each species was determined in field bioassays. Lures with racemic 3-hydroxy-2-hexanone and 2-nonanone as single compounds were not attractive to A. mysticus. However, the compounds acted synergistically in blends of 100:100 and 160:100 of 2-nonanone to the hydroxyketone's (R)-enantiomer, but not in a 40:100 blend. Similarly (S)-2-hydroxy-3-octanone and its racemate attracted significantly more X. antilope than controls. Males and females of both species were captured in approximately equal numbers. The aggregation-sex pheromones of A. mysticus and X.antilope have high potential to serve as sensitive and efficient tools for detection and monitoring of local populations, and in studies of the species' ecology and conservation requirements.
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| 10. |
- Nilsson, Klara, et al.
(författare)
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Pasting and gelation of faba bean starch-protein mixtures
- 2023
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 138, s. 108494-
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Tidskriftsartikel (refereegranskat)abstract
- Starch and protein are major components in many foods, contributing to nutritional and textural properties. Understanding how the behaviour and interactions of these components contribute to different textures is important. In this study, mixed gel systems were created with different ratios of starch to protein (constant solid content 12%) extracted from faba bean, a promising crop for locally produced plant-based foods in cold climate regions. The mixed starch-protein gels were characterised in terms of pasting, texture and microstructure. Starch-rich mixtures showed higher water binding and water absorption than samples with higher protein content. A tendency for more efficient hydration in starch-rich samples was confirmed by NMR. Iodine affinity appeared to be lower for high-protein samples, particularly at higher temperatures. Mixtures with high starch content also showed higher viscosity during pasting, higher storage modulus throughout gelation, lower tan delta and lower frequency dependence of the final gel. Characterisation by compression tests showed stronger and more elastic gels with increasing starch content. Light microscopy revealed that starch granules were tightly packed, espe-cially at higher starch content, with protein filling the spaces between starch granules. SEM micrographs revealed a network structure with larger pores and thicker strands in samples with higher starch content. Overall, increasing protein content reduced viscosity during pasting and caused softer gels, likely owing to different gelation and hydration properties of starch and protein.
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