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1.
Membrane Dynamics and Multiple Functions of Oil Bodies in Seeds and Leaves.
Shimada, TL, Hayashi, M, Hara-Nishimura, I
Plant physiology. 2018;(1):199-207
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Abstract
Oil bodies have multiple functions: oleosin-mediated freezing tolerance of seeds, direct interaction with glyoxysomes for lipid degradation in seedlings, and antifungal compound production in leaves.
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2.
Wheat seed transcriptome reveals genes controlling key traits for human preference and crop adaptation.
Henry, RJ, Furtado, A, Rangan, P
Current opinion in plant biology. 2018;(Pt B):231-236
Abstract
Analysis of the transcriptome of the developing wheat grain has associated expression of genes with traits involving production (e.g. yield) and quality (e.g. bread quality). Photosynthesis in the grain may be important in retaining carbon that would be lost in respiration during grain filling and may contribute to yield in the late stages of seed formation under warm and dry environments. A small number of genes have been identified as having been selected by humans to optimize the performance of wheat for foods such as bread. Genes determining flour yield in milling have been discovered. Hardness is explained by variations in expression of pin genes. Knowledge of these genes should dramatically improve the efficiency of breeding better climate adapted wheat genotypes.
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3.
Seed coats as an alternative molecular factory: thinking outside the box.
Francoz, E, Lepiniec, L, North, HM
Plant reproduction. 2018;(3):327-342
Abstract
Seed coats as commodities. Seed coats play important roles in the protection of the embryo from biological attack and physical damage by the environment as well as dispersion strategies. A significant part of the energy devoted by the mother plant to seed production is channeled into the production of the cell layers and metabolites that surround the embryo. Nevertheless, in crop species these are often discarded post-harvest and are a wasted resource that could be processed to yield co-products. The production of novel compounds from existing metabolites is also a possibility. A number of macromolecules are already accumulated in these maternal layers that could be exploited in industrial applications either directly or via green chemistry, notably flavonoids, lignin, lignan, polysaccharides, lipid polyesters and waxes. Here, we summarize our knowledge of the in planta biosynthesis pathways of these macromolecules and their molecular regulation as well as potential applications. We also outline recent work aimed at providing further tools for increasing yields of existing molecules or the development of novel biotech approaches, as well as trial studies aimed at exploiting this underused resource.
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Seed germination and seedling allogamy in Rosmarinus officinalis: the costs of inbreeding.
Garcia-Fayos, P, Castellanos, MC, Segarra-Moragues, JG
Plant biology (Stuttgart, Germany). 2018;(3):627-635
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Abstract
Self-pollination by geitonogamy is likely in self-compatible plants that simultaneously expose a large number of flowers to pollinators. However, progeny of these plants is often highly allogamous. Although mechanisms to increase cross-pollination have been identified and studied, their relative importance has rarely been addressed simultaneously in plant populations. We used Rosmarinus officinalis to explore factors that influence the probability of self-fertilisation due to geitonogamy or that purge its consequences, focusing on their effects on seed germination and allogamy rate. We experimentally tested the effect of geitonogamy on the proportion of filled seeds and how it influences germination rate. During two field seasons, we studied how life history and flowering traits of individuals influence seed germination and allogamy rates of their progeny in wild populations at the extremes of the altitudinal range. The traits considered were plant size, population density, duration of the flowering season, number of open flowers, flowering synchrony among individuals within populations and proportion of male-sterile flowers. We found that most seeds obtained experimentally from self-pollination were apparently healthy but empty, and that the proportion of filled seeds drove the differences in germination rate between self- and cross-pollination experiments. Plants from wild populations consistently had low germination rate and high rate of allogamy, as determined with microsatellites. Germination rate related positively to the length of the flowering season, flowering synchrony and the ratio of male-sterile flowers, whereas the rate of allogamous seedlings was positively related only to the ratio of male-sterile flowers. Rosemary plants purge most of the inbreeding caused by its pollination system by aborting the seeds. This study showed that the rates of seed germination and allogamy of the seedlings depend on a complex combination of factors that vary in space and time. Male sterility of flowers, length of the flowering season and flowering synchrony of individuals within populations all favour high rates of cross-pollination, therefore increasing germination and allogamy rates. Flowering traits appear to be highly plastic and respond to local and seasonal conditions.
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5.
Steady and dynamic shear rheological behavior of semi dilute Alyssum homolocarpum seed gum solutions: influence of concentration, temperature and heating-cooling rate.
Alaeddini, B, Koocheki, A, Mohammadzadeh Milani, J, Razavi, SMA, Ghanbarzadeh, B
Journal of the science of food and agriculture. 2018;(7):2713-2720
Abstract
BACKGROUND Alyssum homolocarpum seed gum (AHSG) solution exhibits high viscosity at low shear rates and has anionic features. However there is no information regarding the flow and dynamic properties of this gum in semi-dilute solutions. The present study aimed to investigate the dynamic and steady shear behavior of AHSG in the semi-dilute region. RESULTS The viscosity profile demonestrated a shear thinning behavior at all temperatures and concentrations. An increase in the AHSG concentration was acompanied by an increase in the pseudoplasticity degree, whereas, by increasing the temperature, the pseudoplasticity of AHSG decreased. At low gum concentration, solutions had more viscosity dependence on temperature. The mechanical spectra obtained from the frequency sweep experiment demonstrated viscoelastic properties for gum solutions. AHSG solutions showed typical weak gel-like behavior, revealing G' greater than G' within the experimental range of frequency (Hz), with slight frequency dependency. The influence of temperature on viscoelastic properties of AHSG solutions was studied during both heating (5-85 °C) and cooling (85-5 °C) processes. The complex viscosity of AHSG was greater compared to the apparent viscosity, indicating the disruption of AHSG network structure under continuous shear rates and deviation from the Cox-Merz rule. During the initial heating, the storage modulus showed a decreasing trend and, with a further increase in temperature, the magnitude of storage modulus increased. The influence of temperature on the storage modulus was considerable when a higher heating rate was applied. CONCLUSION AHSG can be applied as a thickening and stabilizing agents in food products that require good stability against temperature. © 2017 Society of Chemical Industry.
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6.
Meta-QTL analysis of seed iron and zinc concentration and content in common bean (Phaseolus vulgaris L.).
Izquierdo, P, Astudillo, C, Blair, MW, Iqbal, AM, Raatz, B, Cichy, KA
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik. 2018;(8):1645-1658
Abstract
Twelve meta-QTL for seed Fe and Zn concentration and/or content were identified from 87 QTL originating from seven population grown in sixteen field trials. These meta-QTL include 2 specific to iron, 2 specific to zinc and 8 that co-localize for iron and zinc concentrations and/or content. Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification breeding programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrient deficiencies. Biofortification efforts thus far have relied on phenotypic selection of raw seed mineral concentrations in advanced generations. While numerous quantitative trait loci (QTL) studies have been conducted to identify genomic regions associated with increased Fe and Zn concentration in seeds, these results have yet to be employed for marker-assisted breeding. The objective of this study was to conduct a meta-analysis from seven QTL studies in Andean and Middle American intra- and inter-gene pool populations to identify the regions in the genome that control the Fe and Zn levels in seeds. Two meta-QTL specific to Fe and two meta-QTL specific to Zn were identified. Additionally, eight Meta QTL that co-localized for Fe and Zn concentration and/or content were identified across seven chromosomes. The Fe and Zn shared meta-QTL could be useful candidates for marker-assisted breeding to simultaneously increase seed Fe and Zn. The physical positions for 12 individual meta-QTL were identified and within five of the meta-QTL, candidate genes were identified from six gene families that have been associated with transport of iron and zinc in plants.
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New insights into auxin metabolism in Bradyrhizobium japonicum.
Torres, D, Benavidez, I, Donadio, F, Mongiardini, E, Rosas, S, Spaepen, S, Vanderleyden, J, Pěnčík, A, Novák, O, Strnad, M, et al
Research in microbiology. 2018;(6):313-323
Abstract
Bacterial metabolism of phytohormones includes several processes such as biosynthesis, catabolism, conjugation, hydrolysis and homeostatic regulation. However, only biosynthesis and occasionally catabolism are studied in depth in microorganisms. In this work, we evaluated and reconsidered IAA metabolism in Bradyrhizobiumjaponicum E109, one of the most widely used strains for soybean inoculation around the world. The genomic analysis of the strain showed the presence of several genes responsible for IAA biosynthesis, mainly via indole-3-acetonitrile (IAN), indole-3-acetamide (IAM) and tryptamine (TAM) pathways. However; in vitro experiments showed that IAA is not accumulated in the culture medium in significant amounts. On the contrary, a strong degradation activity was observed after exogenous addition of 0.1 mM of IAA, IBA or NAA to the medium. B. japonicum E109 was not able to grow in culture medium containing IAA as a sole carbon source. In YEM medium, the bacteria degraded IAA and hydrolyzed amino acid auxin conjugates with alanine (IAAla), phenylalanine (IAPhe), and leucine (IAPhe), releasing IAA which was quickly degraded. Finally, the presence of exogenous IAA induced physiological changes in the bacteria such as increased biomass and exopolysaccharide production, as well as infection effectiveness and symbiotic behavior in soybean plants.
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8.
Seed tissue and nutrient partitioning, a case for the nucellus.
Lu, J, Magnani, E
Plant reproduction. 2018;(3):309-317
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Abstract
Flowering plants display a large spectrum of seed architectures. The volume ratio of maternal versus zygotic seed tissues changes considerably among species and underlies different nutrient-storing strategies. Such diversity arose through the evolution of cell elimination programs that regulate the relative growth of one tissue over another to become the major storage compartment. The elimination of the nucellus maternal tissue is regulated by developmental programs that marked the origin of angiosperms and outlined the most ancient seed architectures. This review focuses on such a defining mechanism for seed evolution and discusses the role of nucellus development in seed tissues and nutrient partitioning at the light of novel discoveries on its molecular regulation.
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9.
Saving seed microbiomes.
Berg, G, Raaijmakers, JM
The ISME journal. 2018;(5):1167-1170
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Abstract
Plant seeds are home to diverse microbial communities whose composition is determined by plant genotype, environment, and management practices. Plant domestication is now recognized as an important driver of plant-associated microbial diversity. To what extent and how domestication affects seed microbiomes is less well studied. Here we propose a 'back-to-the-future' approach to harness seed microbiomes of wild relatives of crop cultivars to save and re-instate missing beneficial seed microbes for improved plant tolerance to biotic and abiotic stress.
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10.
Saponins from seeds of Genus Camellia: Phytochemistry and bioactivity.
Guo, N, Tong, T, Ren, N, Tu, Y, Li, B
Phytochemistry. 2018;:42-55
Abstract
Camellia seeds have been traditionally used as oil raw materials in Asia, and are known for a wide spectrum of applications. Oleanane-type triterpene saponins are the major specialised metabolites in Camellia seeds, and more than seventy saponins have been isolated and characterized. These natural compounds have caught much attention due to their various biological and pharmacological activities, including modulation of gastrointestinal system, anti-cancer, anti-inflammation, anti-microorganism, antioxidation, neuroprotection, hypolipidemic effects, foaming and detergence, as well as helping the accumulation of pollutants by plants. These compounds have a promising application in medicine, agriculture, industry and environmental protection. The present paper summarized the information from current publications on Camellia seed saponins, with a focus on the advances made in chemical structures, determination methods, bioactivities and toxicity. We hope this article will stimulate further investigations on these compounds.