Seed Storage Reserves Research Articles

Cryopreservation of herbaceous Asteraceae seeds: Effects of seed reserves on seed germination and seedling regrowth

Carbohydrate, lipid and protein, the three main storage reserves of seeds, are the main sources of raw materials and energy for seed germination and early growth stage of seedlings. In this study, the seed of 16 Asteraceae herbaceous ornamentals were used to compare the changes in seed germination, seedling growth indexes and four major storage reserves of seeds before and after cryopreservation. After cryopreservation, seed germination and seedling growth were preserved in most species (11/16), while one species showed significantly improved post-thaw germination and four had decreased germination. In seeds with preserved germination, no clear variation was noted with regards to the four kinds of storage reserves, or only a slight change in one. However, significantly reduced soluble protein, soluble sugar and fat content and increased starch content were detected in seeds showing reduced germination after cryopreservation. The correlation study further showed that the changes in seed germination were positively correlated with soluble protein, soluble sugar and fat, and negatively correlated with starch. In seedling growth indexes, only cotyledon area was correlated to the content of soluble protein, starch, fat, and seed germination after cryopreservation. These results support the use of soluble protein, soluble sugar, starch and fat as indicators of seed germination after cryopreservation, but not for predicting the seedling growth indexes.

Expression of malic enzyme reveals subcellular carbon partitioning for storage reserve production in soybeans.

Central metabolism produces amino and fatty acids for protein and lipids that establish seed value. Biosynthesis of storage reserves occurs in multiple organelles that exchange central intermediates including two essential metabolites, malate, and pyruvate that are linked by malic enzyme. Malic enzyme can be active in multiple subcellular compartments, partitioning carbon and reducing equivalents for anabolic and catabolic requirements. Prior studies based on isotopic labeling and steady-state metabolic flux analyses indicated malic enzyme provides carbon for fatty acid biosynthesis in plants, though genetic evidence confirming this role is lacking. We hypothesized that increasing malic enzyme flux would alter carbon partitioning and result in increased lipid levels in soybeans. Homozygous transgenic soybean plants expressing Arabidopsis malic enzyme alleles, targeting the translational products to plastid or outside the plastid during seed development, were verified by transcript and enzyme activity analyses, organelle proteomics, and transient expression assays. Protein, oil, central metabolites, cofactors, and acyl-acyl carrier protein (ACPs) levels were quantified overdevelopment. Amino and fatty acid levels were altered resulting in an increase in lipids by 0.5-2% of seed biomass (i.e. 2-9% change in oil). Subcellular targeting of a single gene product in central metabolism impacts carbon and reducing equivalent partitioning for seed storage reserves in soybeans.

Linum usitatissimum ABI3 enhances the accumulation of seed storage reserves and tolerance to environmental stresses during seed germination and seedling establishment in Arabidopsis thaliana

Flax (Linum usitatissimum) is an important oil crop in arid and semi-arid regions of North and Northwest China, and its seeds are rich in nutritious storage reserves, such as polyunsaturated fatty acids (FAs) and proteins. However, the regulatory networks that control the accumulation of seed storage reserves in flax are still largely unknown. In this study, we found that LuABI3-1 and LuABI3-2 homologs from the flax cultivar ‘Longya 10’ play important roles in regulating the accumulation of seed storage reserves in Arabidopsis thaliana. The results of subcellular localization and transcriptional activity assays showed that both LuABI3-1 and LuABI3-2 function as transcription factors. Overexpression of either LuABI3-1 or LuABI3-2 resulted in the significant increase in the contents of total seed FAs and storage proteins, but did not alter other key agronomic traits in A. thaliana. Accordingly, the expression of key genes involved in the biosynthesis of FAs and storage proteins was also greatly up-regulated in the developing seeds of LuABI3-1-overexpression lines. Additionally, both LuABI3-1 and LuABI3-2 enhanced the tolerance to the high salt and mannitol stresses during seed germination and seedling establishment in A. thaliana. These results increase our understanding of the LuABI3 regulatory functions and provide promising targets for genetic manipulation of L. usitatissimum to innovate the germplasm resources and cultivate high yield and quality varieties.

Linum usitatissimum FUSCA3–1 regulates plant architecture and seed storage reserve accumulation in Arabidopsis thaliana

Flax ( Linum usitatissimum L.) as a self-pollinated annual diploid crop is grown worldwide primarily for its seed storage reserves of oil and storage proteins. The B3 domain transcription factor AtFUSCA3 (AtFUS3) has been identified as a master regulator of seed storage reserve accumulation in Arabidopsis thaliana . However, the function of LuFUS3 from L. usitatissimum has not yet been assessed. Here, we found that there were two LuFUS3 homologs, LuFUS3–1 and LuFUS3–2, in the L. usitatissimum genome. The subcellular localization and yeast transcriptional activation assays indicated that LuFUS3–1 functions as a transcription factor. Heterogeneous expression of LuFUS3–1 in the A. thaliana wild type background changed the plant architecture, including moderately dwarf stature, wrinkled leaves, increased branch number, altered floral morphology, and shorter and wider siliques, which was at least partially caused by the significantly decreased level of endogenous gibberellins. On the other hand, we demonstrated that LuFUS3–1 enhances the accumulation of seed storage reserves inclusive of oil and storage proteins in A. thaliana seeds. Consistently, LuFUS3–1 promotes the expression of many genes involved in the biosynthesis of seed oil and storage proteins during seed development. These findings provide new insights into the FUS3 function in plant architecture and seed storage reserve accumulation, and also represent a promising target for genetic modification of L. usitatissimum . • LuFUS3-1 functions as a B3 domain transcription factor. • LuFUS3-1 regulates plant architecture at least dependent on gibberellin biosynthesis. • LuFUS3-1 promotes the accumulation of seed oil and storage proteins. • LuFUS3 boosts the expression of genes involved in seed oil and storage protein biosynthesis.

Carrot (Daucus carota L.) Seed Germination Was Promoted by Hydro-Electro Hybrid Priming Through Regulating the Accumulation of Proteins Involved in Carbohydrate and Protein Metabolism.

Asynchronized and non-uniform seed germination is causing obstacles to the large-scale cultivation of carrot (Daucus carota L.). In the present study, the combination of high voltage electrostatic field treatment (EF) with hydropriming (HYD), namely hydro-electro hybrid priming (HEHP), significantly improved all germination indicators of carrot seeds, and the promoting effect was superior to that of the HYD treatment. A tandem mass tags (TMT)-based proteomic analysis identified 4,936 proteins from the seeds, and the maximum number of differentially abundant proteins (DAPs) appeared between CK and HEHP. KEGG analysis revealed that the upregulated DAPs were mainly enriched in the pathways related to protein synthesis and degradation such as “ribosome” and “proteasome,” while the downregulated DAPs were mainly enriched in photosynthesis-related pathways. Furthermore, the maximum DAPs were annotated in carbohydrate metabolism. Some proteins identified as key enzymes of the glyoxylate cycle, the tricarboxylate cycle, glycolysis and the pentose phosphate pathway showed enhanced abundance in priming treatments. The activities of several key enzymes involved in carbohydrate metabolism were also enhanced by the priming treatments, especially the HEHP treatment. Real-time quantitative PCR (qRT-PCR) analysis revealed that the effect of priming is mainly reflected before sowing. In conclusion, the optimal effect of HEHP is to regulate the synthesis and degradation of proteins in seeds to meet the requirements of germination and initiate the utilization of seed storage reserves and respiratory metabolism. The present work expanded the understanding of the response mechanism of carrot seed germination to priming and the biological effects of high voltage electrostatic field.

Factors influencing seed reserve utilization during seedling establishment in maize inbred lines

Strong seedlings are essential for high yield. To explore the foundation of strong seedlings, we investigated various factors influencing the conversion and distribution of seed storage reserves during seedling establishment in maize inbred lines. Three maize inbred lines were used to explore the effects of seed size, seed vigor, illumination duration, temperature, water content, and salt concentration of the seedling medium on the utilization of seed storage reserves during seedling establishment. The results showed that the conversion rate of small seeds was 3.69 to 17.71% higher than that of large seeds. Moreover, prolonged illumination time was conducive to the formation of strong seedlings. However, low temperature, drought stress and salt stress reduced the conversion rate of seed storage reserves and increased the root/shoot ratio. These results could be used to guide field management during seedling emergence and develop improved germplasm with a high conversion rate of seed storage reserves.

The hydrolysis dynamic of storage reserves in maize seed germination helps to explain differences in inbred lines and hybrid seed vigor

Abstract: Storage reserves composition is directly related to the manifestation of seed vigor. However, the physiological potential expression in inbred lines, as well as hybrids from the storage reserves hydrolysis, is not clear. Thus, the aim of this study was focused on verifying if there are differences in the hydrolysis of seed storage reserve of maize inbred lines or hybrids during germination, and also checking if the changes in hydrolysis are associated with seed vigor. The seeds of inbred lines and hybrids were submitted to germination test, vigor by accelerated aging and cold tolerance. Biochemical profiling (total protein content, soluble proteins, phytate, inorganic phosphorus, starch, and soluble sugars), was temporally determined at 0 h (quiescent seeds), 12 h, 24 h, 30 h, and 48 h after imbibition. The seeds of inbred lines showed a longer time for root protrusion and less vigor when compared to hybrids. The highest hydrolysis rates in inbred lines were observed in phase I and at the end of phase II of germination. In hybrids, the rates remained, on average, constant throughout germination. The greatest differences in the hydrolysis of reserve compounds occur in phase II of germination and differentiate the germination metabolism of hybrids and inbred lines.

Skotomorphogenesis exploits threonine to promote hypocotyl elongation.

Mobilisation of seed storage reserves is important for seedling establishment in Arabidopsis. In this process, sucrose is synthesised from triacylglycerol via core metabolic processes. Mutants with defects in triacylglycerol-to-sucrose conversion display short etiolated seedlings. We found that whereas sucrose content in the indole-3-butyric acid response 10 (ibr10) mutant was significantly reduced, hypocotyl elongation in the dark was unaffected, questioning the role of IBR10 in this process. To dissect the metabolic complexity behind cell elongation, a quantitative-based phenotypic analysis combined with a multi-platform metabolomics approach was applied. We revealed that triacylglycerol and diacylglycerol breakdown were disrupted in ibr10, resulting in low sugar content and poor photosynthetic ability. Importantly, batch-learning self-organised map clustering revealed that threonine level was correlated with hypocotyl length. Consistently, exogenous threonine supply stimulated hypocotyl elongation, indicating that sucrose levels are not always correlated with etiolated seedling length, suggesting the contribution of amino acids in this process.

Crosstalk during the Carbon-Nitrogen Cycle That Interlinks the Biosynthesis, Mobilization and Accumulation of Seed Storage Reserves.

Carbohydrates are the major storage reserves in seeds, and they are produced and accumulated in specific tissues during the growth and development of a plant. The storage products are hydrolyzed into a mobile form, and they are then translocated to the developing tissue following seed germination, thereby ensuring new plant formation and seedling vigor. The utilization of seed reserves is an important characteristic of seed quality. This review focuses on the seed storage reserve composition, source–sink relations and partitioning of the major transported carbohydrate form, i.e., sucrose, into different reserves through sucrolytic processes, biosynthetic pathways, interchanging levels during mobilization and crosstalk based on vital biochemical pathways that interlink the carbon and nitrogen cycles. Seed storage reserves are important due to their nutritional value; therefore, novel approaches to augmenting the targeted storage reserve are also discussed.

Hydro-Electro Hybrid Priming Promotes Carrot (Daucus carota L.) Seed Germination by Activating Lipid Utilization and Respiratory Metabolism.

Carrot (Daucus carota L.) is widely cultivated as one of the most important root crops, and developing an effective presowing treatment method can promote the development of modern mechanized precision sowing. In the present study, a novel seed priming technology, named hydro-electro hybrid priming (HEHP), was used to promote the germination of carrot seeds. Seed germination experiments showed that HEHP was able to increase the germination index (GI) and vigor index (VI) by 3.1-fold and 6.8-fold, respectively, and the effect was significantly superior to that of hydro-priming (HYD) and electrostatic field treatment (EF). The consumption and utilization rate of seed storage reserves were also greatly improved. Meanwhile, both glyoxysomes and mitochondria were found to appear ahead of time in the endosperm cells of HEHP through observations of the subcellular structure of the endosperm. Activities of isocitrate lyase (ICL), NAD-dependent malate dehydrogenase (MDH), pyruvate kinase (PK), and alcohol dehydrogenase (ADH) were significantly increased by HEHP. From transcriptome results, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to the glyoxylate cycle, glycolysis, gluconeogenesis, and the citrate cycle were significantly enriched and real-time quantitative PCR (qRT-PCR) analysis confirmed the expression pattern of 15 critical differentially expressed genes (DEGs) in these pathways. All DEGs encoding MDH, phosphoenolpyruvate carboxykinase (PEPCK), and PK were upregulated in HEHP; thus, it is reasonable to infer that the transformation of malate, oxalacetate, phosphoenolpyruvate, and pyruvate in the cytoplasm may be pivotal for the energy supply during early germination. The results suggest that the optimal effect of HEHP is achieved by initiating stored lipid utilization and respiratory metabolism pathways related to germination.

The gibberellin signaling negative regulator RGA-LIKE3 promotes seed storage protein accumulation

Seed storage protein (SSP) acts as one of the main components of seed storage reserves, of which accumulation is tightly mediated by a sophisticated regulatory network. However, whether and how gibberellin (GA) signaling is involved in this important biological event is not fully understood. Here, we show that SSP content in Arabidopsis (Arabidopsis thaliana) is significantly reduced by GA and increased in the GA biosynthesis triple mutant ga3ox1/3/4. Further investigation shows that the DELLA protein RGA-LIKE3 (RGL3), a negative regulator of GA signaling, is important for SSP accumulation. In rgl3 and 35S:RGL3-HA, the expression of SSP genes is down- and upregulated, respectively, compared with that in the wild-type. RGL3 interacts with ABSCISIC ACID INSENSITIVE3 (ABI3), a critical transcription factor for seed developmental processes governing SSP accumulation, both in vivo and in vitro, thus greatly promoting the transcriptional activating ability of ABI3 on SSP genes. In addition, genetic evidence shows that RGL3 and ABI3 regulate SSP accumulation in an interdependent manner. Therefore, we reveal a function of RGL3, a little studied DELLA member, as a coactivator of ABI3 to promote SSP biosynthesis during seed maturation stage. This finding advances the understanding of mechanisms in GA-mediated seed storage reserve accumulation.

Tetracycline stress disturbs the mobilization of protein bodies in seed storage reserves during radicle elongation after seed germination.

Residues of antibiotics in the soil can have adverse effects on crop plants related closely to humans. However, there is a lack of knowledge on the phytotoxicity of antibiotics to sensitive species. The aim of our study was mainly to reveal tetracycline stress on the mobilization of seed storage proteins, lipids, and minerals of Chinese cabbage (Brassica rapa L.) during radicle elongation after germination. The Chinese cabbage seed was incubated for 48 h in tetracycline solutions at 1 and 5 μM. For the cotyledons of the seed, the result of TEM showed that tetracycline significantly hindered the mobilization of protein bodies, which was in line with the result of FTIR spectroscopy. However, the mobilization of oil bodies and mineral bodies in cotyledons was not significantly disturbed by the stress of tetracycline, as well as the energy supply in different organs including the cotyledons, hypocotyl, and radicle of the seed. To our knowledge, this is the first study to demonstrate the disturbance on mobilization of protein bodies in seed storage reserves caused by the stress of tetracycline at low levels during radicle elongation after germination.

TRANSPARENT TESTA GLABRA1, a Key Regulator in Plants with Multiple Roles and Multiple Function Mechanisms.

TRANSPARENT TESTA GLABRA1 (TTG1) is a WD40 repeat protein. The phenotypes caused by loss-of-function of TTG1 were observed about half a century ago, but the TTG1 gene was identified only about twenty years ago. Since then, TTG1 has been found to be a plant-specific regulator with multiple roles and multiple functional mechanisms. TTG1 is involved in the regulation of cell fate determination, secondary metabolisms, accumulation of seed storage reserves, plant responses to biotic and abiotic stresses, and flowering time in plants. In some processes, TTG1 may directly or indirectly regulate the expression of downstream target genes via forming transcription activator complexes with R2R3 MYB and bHLH transcription factors. Whereas in other processes, TTG1 may function alone or interact with other proteins to regulate downstream target genes. On the other hand, the studies on the regulation of TTG1 are very limited. So far, only the B3-domain family transcription factor FUSCA3 (FUS3) has been found to regulate the expression of TTG1, phosphorylation of TTG1 affects its interaction with bHLH transcription factor TT2, and TTG1 proteins can be targeted for degradation by the 26S proteasome. Here, we provide an overview of TTG1, including the identification of TTG1, the functions of TTG1, the possible function mechanisms of TTG1, and the regulation of TTG1. We also proposed potential research directions that may shed new light on the regulation and functional mechanisms of TTG1 in plants.

Arabidopsis MDN1 Is Involved in the Establishment of a Normal Seed Proteome and Seed Germination.

Seed germination and formation are the beginning and ending, respectively, of a plant life cycle. These two processes are under fine regulation by the internal genetic information. Previously, we demonstrated that Arabidopsis MIDASIN 1 (MDN1) is required for ribosome biogenesis, and its dysfunction leads to pleiotropic developmental phenotypes, including impaired embryogenesis and slow seed germination. In this study, we further found that the weak mutant of MDN1, mdn1-1, exhibits an increased seed size phenotype. Seed proteomic analysis reveals that a number of proteins involved in seed development and response to external environments are mis-regulated by the MDN1 dysfunction. Many 2S seed storage proteins (SSPs) and late embryogenesis abundant (LEA) proteins are over-accumulated in the dry seeds of mdn1-1. Further, some genes encoding seed storage reserves are also upregulated in mdn1-1 seedlings. More interestingly, abscisic acid-insensitive 5 (ABI5) is over-accumulated in mdn1-1 seeds, and the loss of its function partially rescues the low seed germination rate of mdn1-1. Together, this study further demonstrates that MDN1 is essential for establishing a normal seed proteome, and its mutation triggers ABI5-mediated repression of seed germination.

Responses of seeds of typical Brassica crops to tetracycline stress: Sensitivity difference and source analysis

Antibiotics can induce adverse effects on plants. Brassica crop seeds, for their advantages, are used widely in seed germination test to investigate phytotoxicity of substances. However, their performances on evaluating antibiotics remain to be studied to select sensitive species for control of potential risks. In this work, common species of Chinese cabbage (Brassica rapa L.), edible rape (Brassica napus L.), and cabbage (Brassica oleracea L.) with three cultivars each were selected to compare and analyze the sensitivity difference of their seeds to tetracycline (TC) stress. Results showed that the ratio of axis to cotyledon (RAC) by fresh weight was an alternative endpoint besides radicle length (RL) in the test. The species sensitivity distribution (SSD) based on the effective concentrations causing x% inhibition (ECx) in RL of seeds exposed to TC was applied to compare the sensitivity of seeds and estimate the hazardous concentration for x% species (HCx). From the species-dependent sensitivity and the sensitivity difference of cultivars in the same species of seeds to TC, the performance of Chinese cabbage was the best in the study. The sensitivity of seeds to TC could be evaluated by EC20 related to seed physical traits and germination indices, while the extent of seeds affected by TC could be evaluated by EC50 related to the composition of seed storage reserves. We recommended that it was a new idea to analyze responses of different seeds to TC at large scale according to seed innate characteristics.

Rapid and non-destructive evaluation of seed quality of Chinese fir by near infrared spectroscopy and multivariate discriminant analysis

Chinese fir (Cunninghamia lanceolata (Lamb) Hook) is a promising timber species for planting in the sub-tropical ecosystem. However, the germination rate of Chinese fir seed lots is low, and viability determination by conventional methods (germination test and tetrazolium test) is time-consuming and destructive. Therefore, the aim of this study was to investigate the potential of Near Infrared (NIR) spectroscopy for rapidly and non-destructively determining viability of Chinese fir seeds. A total of 450 seeds was first identified as viable, empty, or dead (n = 150 seeds per seed lot fraction) by digital X-ray and their viability was further confirmed by germination test. NIR reflectance spectra were collected from single seeds using XDS Rapid Content Analyzer from 780 to 2500 nm. Classification models were developed on calibration set (n = 300 seeds) by Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA) using the entire or selected NIR regions, and the fitted models were validated using external test set (n = 150 seeds). The model’s ability to recognize members (sensitivity) while rejecting non-members (specificity) of a given class was 100% for viable and dead seeds and 98% for empty seeds, attesting to the model’s robustness. When the model was fitted in the shorter NIR region (780–1100 nm), the sensitivity and specificity reached 100% for all seed lot fractions. The mean classification accuracy was 99% in the full and longer NIR regions and 100% in the shorter NIR region. The spectral differences among seed lot fractions could be attributed to differences in seed coat chemical composition in empty and dead seeds, presumably tannin content, and major storage reserves in viable seeds, notably fatty acids, proteins, and carbohydrate. It can be concluded that NIR spectroscopy has a great potential to evaluate Chinese fir seed quality, which could be applied in the development of an on-line sorting system.

Quantitative Proteomics Analysis of Barley-Based Liquid Feed and the Effect of Protease Inhibitors and NADPH-Dependent Thioredoxin Reductase/Thioredoxin (NTR/Trx) System.

Liquid feeding strategies have been devised with the aim of enhancing grain nutrient availability for livestock. It is characterized by a steeping/soaking period that softens the grains and initiates mobilization of seed storage reserves. The present study uses 2D gel-based proteomics to investigate the role of proteolysis and reduction by thioredoxins over a 48 h steeping period by monitoring protein abundance dynamics in barley-based liquid feed samples supplemented with either protease inhibitors or NADPH-dependent thioredoxin reductase/thioredoxin (NTR/Trx). Several full-length storage proteins were only identified in the water-extractable fraction of feed containing protease inhibitors, illustrating significant inhibition of proteolytic activities arising during the steeping period. Application of functional NTR/Trx to liquid feed reductively increased the solubility of known and potentially new Trx-target proteins, e.g., outer membrane protein X, and their susceptibility to proteolysis. Thus, the NTR/Trx system exhibits important potential as a feed additive to enhance nutrient digestibility in monogastric animals.

E2FA and E2FB transcription factors coordinate cell proliferation with seed maturation.

ABSTRACTThe E2F transcription factors and the RETINOBLASTOMA-RELATED repressor protein are principal regulators coordinating cell proliferation with differentiation, but their role during seed development is little understood. We show that in fully developed Arabidopsis thaliana embryos, cell number was not affected either in single or double mutants for the activator-type E2FA and E2FB. Accordingly, these E2Fs are only partially required for the expression of cell cycle genes. In contrast, the expression of key seed maturation genes LEAFY COTYLEDON 1/2 (LEC1/2), ABSCISIC ACID INSENSITIVE 3, FUSCA 3 and WRINKLED 1 is upregulated in the e2fab double mutant embryo. In accordance, E2FA directly regulates LEC2, and mutation at the consensus E2F-binding site in the LEC2 promoter de-represses its activity during the proliferative stage of seed development. In addition, the major seed storage reserve proteins, 12S globulin and 2S albumin, became prematurely accumulated at the proliferating phase of seed development in the e2fab double mutant. Our findings reveal a repressor function of the activator E2Fs to restrict the seed maturation programme until the cell proliferation phase is completed.

High salinity impacts germination of the halophyte Cakile maritima but primes seeds for rapid germination upon stress release.

Seed germination recovery aptitude is an adaptive trait of overriding significance for the successful establishment and dispersal of extremophile plants in their native ecosystems. Cakile maritima is an annual halophyte frequent on Mediterranean coasts, which produces transiently dormant seeds under high salinity, that germinate fast when soil salinity is lowered by rainfall. Here, we report ecophysiological and proteomic data about (1) the effect of high salt (200 mM NaCl) on the early developmental stages (germination and seedling) and (2) the seed germination recovery capacity of this species. Upon salt exposure, seed germination was severely inhibited and delayed and seedling length was restricted. Interestingly, non-germinated seeds remained viable, showing high germination percentage and faster germination than the control seeds after their transfer onto distilled water. The plant phenotypic plasticity during germination was better highlighted by the proteomic data. Salt exposure triggered (1) a marked slower degradation of seed storage reserves and (2) a significant lower abundance of proteins involved in several biological processes (primary metabolism, energy, stress-response, folding and stability). Yet, these proteins showed strong increased abundance early after stress release, thereby sustaining the faster seed storage proteins mobilization under recovery conditions compared to the control. Overall, as part of the plant survival strategy, C. maritima seems to avoid germination and establishment under high salinity. However, this harsh condition may have a priming-like effect, boosting seed germination and vigor under post-stress conditions, sustained by active metabolic machinery.

Synthesis of Bio‐Based Polyurethanes from Jojoba Oil

Jojoba grows easily in harsh conditions and is the only plant species known to use liquid wax esters as a primary seed storage reserve. Jojoba oil is composed by two mono unsaturated hydrocarbon chains linked by an ester moiety and represents 50% of the weight of seeds. Hence, this atypical oil is, for the first time, dedicated to the synthesis of innovative polymer materials. Novel partially biobased polyurethanes materials are obtained with various structures. New biobased diol is first achieved by addition of mercaptoethanol by thiol‐ene coupling on jojoba oil and characterized by 1H NMR and 13C NMR. The functionalized oil is used to synthesize polyurethane prepolymers by catalyst‐free reaction with various diisocyanates: 1,6‐hexamethylene diisocyanate and 4,4‐methylene diphenyl diisocyanate. After the addition of chain extenders, the obtained polyurethane materials are characterized by 1H NMR, TGA, DSC, and DMA analyses. Various PUs are obtained in terms of flexibility and thermal stability.Practical Applications: The synthesized jojoba oil‐based PUs exhibit a good flexibility. Hence, these biobased PUs could replace petroleum‐based polyurethanes in industry and particularly as coatings, binders or compounds for automotive and aircraft industries.Innovative greener polyurethanes are achieved from jojoba oil with one‐step thiol‐ene reaction and various diisocyanates.