المؤلفون: Brooks, Christopher, Atamian, Hagop, Harmer, Stacey

المصدر: PLoS Biology. 21(10)

مصطلحات موضوعية: Helianthus, Phototropins, Sunlight, Light, Phototropism, Signal Transduction, Arabidopsis Proteins

الوصف: Sunflowers are famous for their ability to track the sun throughout the day and then reorient at night to face east the following morning. This occurs by differential growth patterns, with the east sides of stems growing more during the day and the west sides of stems growing more at night. This process, termed heliotropism, is generally believed to be a specialized form of phototropism; however, the underlying mechanism is unknown. To better understand heliotropism, we compared gene expression patterns in plants undergoing phototropism in a controlled environment and in plants initiating and maintaining heliotropic growth in the field. We found the expected transcriptome signatures of phototropin-mediated phototropism in sunflower stems bending towards monochromatic blue light. Surprisingly, the expression patterns of these phototropism-regulated genes are quite different in heliotropic plants. Most genes rapidly induced during phototropism display only minor differences in expression across solar tracking stems. However, some genes that are both rapidly induced during phototropism and are implicated in growth responses to foliar shade are rapidly induced on the west sides of stems at the onset of heliotropism, suggesting a possible role for red light photoreceptors in solar tracking. To test the involvement of different photoreceptor signaling pathways in heliotropism, we modulated the light environment of plants initiating solar tracking. We found that depletion of either red and far-red light or blue light did not hinder the initiation or maintenance of heliotropism in the field. Together, our results suggest that the transcriptional regulation of heliotropism is distinct from phototropin-mediated phototropism and likely involves inputs from multiple light signaling pathways.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/21c394q1Test

المؤلفون: Moussa Nid Ahmed, Jamila Gagour, Abderrahim Asbbane, Otmane Hallouch, Lahoucine Atrach, Angelo Maria Giuffrè, Khalid Majourhat, Said Gharby

المصدر: Analytica, Vol 5, Iss 2, Pp 273-294 (2024)

مصطلحات موضوعية: sunflower oil, Helianthus annuus L., synthetic antioxidants, vitamin A, Analytical chemistry, QD71-142

الوصف: The present investigation was performed to evaluate the effects of various synthetic antioxidants (vitamin A, vitamin E, β-carotene, and BHT) on the oxidation of sunflower oil subjected to accelerated thermal storage at 60 °C for three months (12 weeks). The performance of the antioxidants studied was evaluated using several quality parameters: the free fatty acid value (FFA), primary oxidation (via the peroxide value (PV) and K232 value), secondary oxidation products (via the anisidine value (p-AV) and K270 value), and the total oxidation value (TOTOX). The fatty acid composition (FAC), oxidizability value (COX), iodine value (IV), and pigment content (chlorophyll and carotenoid) were also evaluated. The results revealed that the control sample of sunflower oil exhibited higher susceptibility to oxidative deterioration. Antioxidants at 200 ppm were more effective in preserving the oxidative stability of sunflower oil subjected to accelerated storage compared to the control oil. The smallest increases in all stability parameter indexes were recorded for antioxidant-supplemented sunflower oil. However, the IV and chlorophyll and carotenoid contents were reduced. At 200 ppm, vitamin E and β-carotene showed the greatest stability in sunflower oil, while their combination with vitamin A at 100 ppm of each showed the lowest stability. In addition, synthetic antioxidants provided greater protection against the degradation of polyunsaturated fatty acids (PUFAs). The highest level of PUFA degradation was recorded in the control oil, followed by the oil containing vitamin A. In conclusion, adding synthetic antioxidants to sunflower oil improves its stability during storage. However, some authors associated these molecules with a health risk due to carcinogenic effects as these molecules have been listed as “Generally Recognized As Safe” (GRAS).

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2673-4532/5/2/18Test; https://doaj.org/toc/2673-4532Test

الوصول الحر: https://doaj.org/article/ff8c826107d7463888cce75e026be6a7Test

المؤلفون: Malfi, Rosemary, McFrederick, Quinn, Lozano, Giselle, Irwin, Rebecca, Adler, Lynn

المصدر: Proceedings of the Royal Society B: Biological Sciences. 290(1996)

مصطلحات موضوعية: Bombus impatiens, Crithidia bombi, Helianthus annuus, agroecosystem, pollinator health, sunflower, Bees, Animals, Helianthus, Flowers, Pollen, Plants, Crithidia

الوصف: Community diversity can reduce the prevalence and spread of disease, but certain species may play a disproportionate role in diluting or amplifying pathogens. Flowers act as both sources of nutrition and sites of pathogen transmission, but the effects of specific plant species in shaping bee disease dynamics are not well understood. We evaluated whether plantings of sunflower (Helianthus annuus), whose pollen reduces infection by some pathogens when fed to bees in captivity, lowered pathogen levels and increased reproduction in free-foraging bumblebee colonies (Bombus impatiens). Sunflower abundance reduced the prevalence of a common gut pathogen, Crithidia bombi, and reduced infection intensity, with an order of magnitude lower infection intensity at high sunflower sites compared with sites with little to no sunflower. Sunflower abundance was also positively associated with greater queen production in colonies. Sunflower did not affect prevalence of other detected pathogens. This work demonstrates that a single plant species can drive disease dynamics in foraging B. impatiens, and that sunflower plantings can be used as a tool for mitigating a prevalent pathogen while also increasing reproduction of an agriculturally important bee species.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/7101h3spTest
https://escholarship.org/content/qt7101h3sp/qt7101h3sp.pdfTest

المؤلفون: Marshall, Carine M, Thompson, Veronica L, Creux, Nicky M, Harmer, Stacey L

مصطلحات موضوعية: Sleep Research, Circadian Clocks, Helianthus, Circadian Rhythm, Reproduction, Helianthus annuus, external coincidence model, anthesis, spiral phyllotaxy, rhythms, floral organs, Other, developmental biology, plant biology, Biochemistry and Cell Biology

الوصف: Biological rhythms are ubiquitous. They can be generated by circadian oscillators, which produce daily rhythms in physiology and behavior, as well as by developmental oscillators such as the segmentation clock, which periodically produces modular developmental units. Here, we show that the circadian clock controls the timing of late-stage floret development, or anthesis, in domesticated sunflowers. In these plants, up to thousands of individual florets are tightly packed onto a capitulum disk. While early floret development occurs continuously across capitula to generate iconic spiral phyllotaxy, during anthesis floret development occurs in discrete ring-like pseudowhorls with up to hundreds of florets undergoing simultaneous maturation. We demonstrate circadian regulation of floral organ growth and show that the effects of light on this process are time-of-day dependent. Delays in the phase of floral anthesis delay morning visits by pollinators, while disruption of circadian rhythms in floral organ development causes loss of pseudowhorl formation and large reductions in pollinator visits. We therefore show that the sunflower circadian clock acts in concert with environmental response pathways to tightly synchronize the anthesis of hundreds of florets each day, generating spatial patterns on the developing capitulum disk. This coordinated mass release of floral rewards at predictable times of day likely promotes pollinator visits and plant reproductive success.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/3nz9068qTest

المؤلفون: Marco Moroldo, Nicolas Blanchet, Harold Duruflé, Stéphane Bernillon, Thierry Berton, Olivier Fernandez, Yves Gibon, Annick Moing, Nicolas B. Langlade

المصدر: BMC Genomics, Vol 25, Iss 1, Pp 1-16 (2024)

مصطلحات موضوعية: Sunflower (Helianthus annuus), Abiotic stresses, Metabolome, Liquid chromatography-mass spectrometry, Genome-wide association study, Antioxidants, Biotechnology, TP248.13-248.65, Genetics, QH426-470

الوصف: Abstract Background Abiotic stresses in plants include all the environmental conditions that significantly reduce yields, like drought and heat. One of the most significant effects they exert at the cellular level is the accumulation of reactive oxygen species, which cause extensive damage. Plants possess two mechanisms to counter these molecules, i.e. detoxifying enzymes and non-enzymatic antioxidants, which include many classes of specialized metabolites. Sunflower, the fourth global oilseed, is considered moderately drought resistant. Abiotic stress tolerance in this crop has been studied using many approaches, but the control of specialized metabolites in this context remains poorly understood. Here, we performed the first genome-wide association study using abiotic stress-related specialized metabolites as molecular phenotypes in sunflower. After analyzing leaf specialized metabolites of 450 hybrids using liquid chromatography-mass spectrometry, we selected a subset of these compounds based on their association with previously known abiotic stress-related quantitative trait loci. Eventually, we characterized these molecules and their associated genes. Results We putatively annotated 30 compounds which co-localized with abiotic stress-related quantitative trait loci and which were associated to seven most likely candidate genes. A large proportion of these compounds were potential antioxidants, which was in agreement with the role of specialized metabolites in abiotic stresses. The seven associated most likely candidate genes, instead, mainly belonged to cytochromes P450 and glycosyltransferases, two large superfamilies which catalyze greatly diverse reactions and create a wide variety of chemical modifications. This was consistent with the high plasticity of specialized metabolism in plants. Conclusions This is the first characterization of the genetic control of abiotic stress-related specialized metabolites in sunflower. By providing hints concerning the importance of antioxidant molecules in this biological context, and by highlighting some of the potential molecular mechanisms underlying their biosynthesis, it could pave the way for novel applications in breeding. Although further analyses will be required to better understand this topic, studying how antioxidants contribute to the tolerance to abiotic stresses in sunflower appears as a promising area of research.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/1471-2164Test

الوصول الحر: https://doaj.org/article/ca3935bd706a4de4b8d0647cfd982c6fTest

المؤلفون: Singh, Chandan^{1, 1}, Nath, Ravindra²

المصدر: 12(2):219-222

المؤلفون: Huang, Kaichi, Ostevik, Kate L, Elphinstone, Cassandra, Todesco, Marco, Bercovich, Natalia, Owens, Gregory L, Rieseberg, Loren H

المصدر: Molecular Biology and Evolution. 39(5)

مصطلحات موضوعية: Biotechnology, Genetics, Human Genome, Chromosome Inversion, Gene Flow, Helianthus, Heterozygote, Mutation, inversion, recombination rate, deleterious mutation, transposable element, centromeres, Helianthus, Biochemistry and Cell Biology, Evolutionary Biology

الوصف: Recombination is critical both for accelerating adaptation and purging deleterious mutations. Chromosomal inversions can act as recombination modifiers that suppress local recombination in heterozygotes and thus, under some conditions, are predicted to accumulate such mutations. In this study, we investigated patterns of recombination, transposable element abundance, and coding sequence evolution across the genomes of 1,445 individuals from three sunflower species, as well as within nine inversions segregating within species. We also analyzed the effects of inversion genotypes on 87 phenotypic traits to test for overdominance. We found significant negative correlations of long terminal repeat retrotransposon abundance and deleterious mutations with recombination rates across the genome in all three species. However, we failed to detect an increase in these features in the inversions, except for a modest increase in the proportion of stop codon mutations in several very large or rare inversions. Consistent with this finding, there was little evidence of overdominance of inversions in phenotypes that may relate to fitness. On the other hand, significantly greater load was observed for inversions in populations polymorphic for a given inversion compared to populations monomorphic for one of the arrangements, suggesting that the local state of inversion polymorphism affects deleterious load. These seemingly contradictory results can be explained by the low frequency of inversion heterozygotes in wild sunflower populations, apparently due to divergent selection and associated geographic structure. Inversions contributing to local adaptation represent ideal recombination modifiers, acting to facilitate adaptive divergence with gene flow, while largely escaping the accumulation of deleterious mutations.

الوصول الحر: https://escholarship.org/uc/item/7zd4m6jmTest

المؤلفون: V. A. Gavrilova, L. G. Makarova, T. G. Stupnikova, N. V. Alpatieva, E. B. Kusnetsova, I. N. Anisimova

المصدر: Труды по прикладной ботанике, генетике и селекции, Vol 184, Iss 4, Pp 64-78 (2024)

مصطلحات موضوعية: helianthus annuus, 1000 seed weight, growing season, plant height, downy mildew resistance, marker-assisted selection, Biotechnology, TP248.13-248.65, Botany, QK1-989

الوصف: Background. In recent years, an increase has been observed in the share of sunflower seeds in the confectionery and food industries. There are 30 cultivars and only 3 hybrids for confectionery use among 839 zoned sunflower cultivars and hybrids listed in the State Register for Selection Achievements Admitted for Usage in 2023. Thus, the development of source material for breeding large-seeded cultivars and hybrids remains a relevant task.Materials and methods. The studied material included 90 accessions selected for their large seed size from VIR’s sunflower collection. The following characters were assessed: 1000 seed weight, days from sprouting to maturation, plant height, head diameter, cypsela color and size, and resistance to downy mildew. DNA markers were used to identify accessions with the Rf1 gene and CMS.Results. Accessions k-2818 (Primorsky Territory), k-3633, k-3748, k-3782 (China), and k-3578 (Ukraine) were the best in 1000 seed weight. Russian cvs. ‘Alekseyevsky Krupnoplodny 2’ (k-3552), ‘Gyar-Gyar’ (k-1589), ‘SPK’ (k-3426), and ‘Lakomka’ (k-3526) confirmed their large seed size. The sterile type of cytoplasm was identified in 12 accessions. Fourteen accessions with fertile cytoplasm had diagnostic markers of the nuclear Rf1 gene.Conclusion. The large-seeded cultivars developed at VNIIMK, ‘SPK’, ‘Lakomka’, and k-3782 from China were the best not only in their large seed size but also in downy mildew resistance. As a result of long-term studies, a trait-specific collection was established for the large seed size trait. It included 90 accessions that can be used in the development of confectionery cultivars. Large-seeded sunflower accessions carrying the Rf1 gene were identified. Some of them became the ancestors of donor lines for both pollen fertility restoration genes and large seed size.

وصف الملف: electronic resource

العلاقة: https://elpub.vir.nw.ru/jour/article/view/1730Test; https://doaj.org/toc/2227-8834Test; https://doaj.org/toc/2619-0982Test

الوصول الحر: https://doaj.org/article/15d4808f54ca46e9a1a4855becd44be7Test

المؤلفون: Oliver Obročník, Viliam Bárek

المصدر: Journal of Water and Land Development, Iss No 59, Pp 50-53 (2024)

مصطلحات موضوعية: dendrometer, drought, helianthus annus, irrigation, water deficit, water stress, River, lake, and water-supply engineering (General), TC401-506, Irrigation engineering. Reclamation of wasteland. Drainage, TC801-978

الوصف: Drought is characterised as a recurring climatic phenomenon with prolonged duration, affecting land through below-average rainfall and often accompanied by high temperatures. When the available water falls below the optimum level, water deficit or water stress arises, disrupting normal plant processes. This condition poses challenges for plant growth and development as it hampers the internal water transport, induces stomatal closure, and limits access to photosynthetic resources. The study employed the annual sunflower as the experimental plant. The plants were cultivated in a controlled environment with a temperature ranging from 20 to 25°C and a humidity level of 55 to 60%, supplemented by MARS HYDRO artificial LED lighting set to a 12-h photoperiod. Radial changes in the plant stems were monitored using a DD-S type dendrometric sensor to measure radial fluctuations. The collected data were recorded in a dendrometric data logger DL 18. Data collection occurred at hourly intervals from February 20 to March 9, 2023. The nine plants were divided into three groups, each comprising three plants. All plants from groups 1 and 2 received irrigation at one- day intervals (group 1 – 80 cm 3 per plant, group 2 – 40 cm 3 per plant) and group 3 was not irrigated. Based on these findings, visible water stress was evident in the plants under experimental conditions. Consequently, continuous monitoring throughout the growing season will be essential to adjust the irrigation rate to meet the requirements of the plants.

وصف الملف: electronic resource

العلاقة: https://journals.pan.pl/Content/129976/2023-04-JWLD-07.pdfTest; https://doaj.org/toc/2083-4535Test

الوصول الحر: https://doaj.org/article/a0068692326947db83f8cde78b129828Test

المؤلفون: Vivian H. Tran, Kristen M. Nolting, Lisa A. Donovan, Andries A. Temme

المصدر: Plant Direct, Vol 8, Iss 4, Pp n/a-n/a (2024)

مصطلحات موضوعية: domestication, drought, Helianthus annuus, leaf theoretical maximum stomatal conductance, osmotic adjustment, resistance, Botany, QK1-989

الوصف: Abstract Cultivated crops are generally expected to have less abiotic stress tolerance than their wild relatives. However, this assumption is not well supported by empirical literature and may depend on the type of stress and how it is imposed, as well as the measure of tolerance being used. Here, we investigated whether wild and cultivated accessions of Helianthus annuus differed in stress tolerance assessed as proportional decline in biomass due to drought and whether wild and cultivated accessions differed in trait responses to drought and trait associations with tolerance. In a greenhouse study, H. annuus accessions in the two domestication classes (eight cultivated and eight wild accessions) received two treatments: a well‐watered control and a moderate drought implemented as a dry down followed by maintenance at a predetermined soil moisture level with automated irrigation. Treatments were imposed at the seedling stage, and plants were harvested after 2 weeks of treatment. The proportional biomass decline in response to drought was 24% for cultivated H. annuus accessions but was not significant for the wild accessions. Thus, using the metric of proportional biomass decline, the cultivated accessions had less drought tolerance. Among accessions, there was no tradeoff between drought tolerance and vigor assessed as biomass in the control treatment. In a multivariate analysis, wild and cultivated accessions did not differ from each other or in response to drought for a subset of morphological, physiological, and allocational traits. Analyzed individually, traits varied in response to drought in wild and/or cultivated accessions, including declines in specific leaf area, leaf theoretical maximum stomatal conductance (gsmax), and stomatal pore length, but there was no treatment response for stomatal density, succulence, or the ability to osmotically adjust. Focusing on traits associations with tolerance, plasticity in gsmax was the most interesting because its association with tolerance differed by domestication class (although the effects were relatively weak) and thus might contribute to lower tolerance of cultivated sunflower. Our H. annuus results support the expectation that stress tolerance is lower in crops than wild relatives under some conditions. However, determining the key traits that underpin differences in moderate drought tolerance between wild and cultivated H. annuus remains elusive.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2475-4455Test

الوصول الحر: https://doaj.org/article/46885a1030f0476aa9fd1cf77f923d92Test