This research aims to investigate the mechanism of the effect of intrinsic and non-intrinsic protein content on the stability of oil bodies (OBs) emulsion gels. We employed small amplitude oscillation shear (SAOS) and large amplitude oscillation shear (LAOS) to measure the linear and nonlinear rheological properties of the OBs emulsion gels. The SAOS test indicated that an increase in non-intrinsic protein content weakened the interaction between OBs, decreasing their storage modulus (G\'). The LAOS test demonstrated that the increase in non-intrinsic protein content affected the structural recombination and destruction behavior of OBs emulsion gels under large strains. Overall, the content of non-intrinsic protein during the extraction process is a crucial factor affecting the stability of OBs emulsion gels. These findings provide insights into the potential strategies for improving oil extraction efficiency and offer a foundation for further investigation into the functional properties of OBs.

In this paper, effects of preheating-induced denaturation of proteins and oleosomes on protein structure and soymilk quality were studied. The protein in soybeans baked at 55 °C (B-55) and 85 °C (B-85) showed an increase of β-sheet content by 3.2 % and a decrease of α-helix content by 3.3 %, indicating that proteins were gradually unfolded while oleosomes remained intact. The protein resisted thermal denaturation during secondary heating, and soymilks were stable as reflected by a small d3,2 (0.4 μm). However, raw soymilk from soybeans baked at 115 °C (B-115), steamed for 1 min (ST-1) and 5 min (ST-5) presented oleosomes destruction and lipids aggregates. The proteins were coated around the oil aggregates. The β-turn content from soybeans steamed for 10 min (ST-10) increased by 9.5 %, with a dense network where the OBs were tightly wrapped, indicating the serious protein denaturation. As a result, the soymilks B-115 or steamed ones were unstable as evidenced by the serious protein aggregation and larger d3,2 (5.65-12.48 μm). Furthermore, the soymilks were graininess and the protein digestion was delayed due to the formation of insoluble protein aggregates. The flavor and early-stage lipid digestion of soymilk from steamed soybeans was improved owing to lipid release.

In angiosperms, basic leucine-zipper (bZIP) TGACG-motif-binding (TGA) transcription factors (TFs) regulate developmental and stress-related processes, the latter often involving NON EXPRESSOR OF PATHOGENESIS-RELATED GENES (NPR) coregulator interactions. To gain insight into their functions in an early diverging land-plant lineage, the single MpTGA and sole MpNPR genes were investigated in the liverwort Marchantia polymorpha. We generated Marchantia MpTGA and MpNPR knockout and overexpression mutants and conducted morphological, transcriptomic and expression studies. Furthermore, we investigated MpTGA interactions with wild-type and mutagenized MpNPR and expanded our analyses including TGA TFs from two streptophyte algae. Mptga mutants fail to induce the switch from vegetative to reproductive development and lack gametangiophore formation. MpTGA and MpNPR proteins interact and Mpnpr mutant analysis reveals a novel coregulatory NPR role in sexual reproduction. Additionally, MpTGA acts independently of MpNPR as a repressor of oil body (OB) formation and can thereby affect herbivory. The single MpTGA TF exerts a dual role in sexual reproduction and OB formation in Marchantia. Common activities of MpTGA/MpNPR in sexual development suggest that coregulatory interactions were established after emergence of land-plant-specific NPR genes and contributed to the diversification of TGA TF functions during land-plant evolution.

Oil bodies serve as a vital energy source of embryos during germination and contribute to sustaining the initial growth of seedlings until photosynthesis initiation. Despite high stability in chemical properties, how oil bodies break down and go into the degradation process during germination is still unknown. This study provides a morphological understanding of the mobilization of stored compounds in the seed germination of Cannabis. The achenes of fibrous hemp cultivar (Cannabis sativa cv. \'Chungsam\') were examined in this study using light microscopy, scanning electron microscopy and transmission electron microscopy. Oil bodies in Cannabis seeds appeared spherical and sporadically distributed in the cotyledonary cells. Protein bodies contained electron-dense globoid and heterogeneous protein matrices. During seed germination, rough endoplasmic reticulum (rER) and high electron-dense substances were present adjacent to the oil bodies. The border of the oil bodies became a dense cluster region and appeared as a sinuous outline. Later, irregular hyaline areas were distributed throughout oil bodies, showing the destabilized emulsification of oil bodies. Finally, the oil bodies lost their morphology and fused with each other. The storage proteins were concentrated in the centre of the protein body as a dense homogenous circular mass surrounded by a light heterogeneous area. Some storage proteins are considered emulsifying agents on the surface region of oil bodies, enabling them to remain stable and distinct within and outside cotyledon cells. At the early germination stage, rER appeared and dense substances aggregated adjacent to the oil bodies. Certain proteins were synthesized within the rER and then translocated into the oil bodies by crossing the half membrane of oil bodies. Our data suggest that rER-associated proteins function as enzymes to lyse the emulsifying proteins, thereby weakening the emulsifying agent on the surface of the oil bodies. This process plays a key role in the degeneration of oil bodies and induces coalescence during seed germination.

Natural oil-in-water emulsions containing plant oil bodies (OBs), also called oleosomes, rich in health-promoting omega-3 polyunsaturated fatty acids (ω3 PUFA) are of increasing interest for food applications. In this study, we focused on walnut kernel OBs (WK-OBs) and explored their microstructure, composition and physical stability in ionic environments as well as the impact of homogenization. A green process involving aqueous extraction by grinding of WK allowed the co-extraction of OBs and proteins, and centrifugation was used to recover the WK-OBs. Confocal laser scanning microscopy images showed the spherical shape of WK-OBs with an oil core envelopped by a layer of phospholipids (0.16 % of lipids) and embedded proteins. Their mean diameter was 5.1 ± 0.3 µm. The WK-OBs contained 70.1 % PUFA with 57.8 % ω6 linoleic acid and 12.3 % ω3 α-linolenic acid representing 68 % and 11.6 % of the total fatty acids in the sn-2 position of the triacylglycerols (TAG), respectively. Trilinolein was the main TAG (23.1 %). The WK-OBs also contained sterols (1223 ± 33 mg/kg lipids; 86 % β-sitosterol), carotenoids (0.62 ± 0.01 mg/kg lipids; 49.2 % β-carotene), and tocopherols (322.7 ± 7.7 mg/kg lipids; 89 % γ-tocopherol), confirming their interest as health-promoting ingredients. The decrease in the size of WK-OBs under high-pressure homogenization avoided phase separation upon storage. The anionic WK-OB surface at neutral pH was affected by stressful ionic environments (pH, NaCl, CaCl2), that induced aggregation of WK-OBs and decreased the physical stability of the emulsions. Emulsions containing WK-OBs are promising to diversify the market of the ω3-rich plant-based food products and beverages.

Hydroxysteroid dehydrogenase (HSDs) is an oil-body sterol protein (steroleosin) with an NADP(H) binding domain that belongs to the short-chain dehydrogenase/reductase (SDR) superfamily. There are numerous studies on the characterization of HSDs in plants. However, thus far, the evolutionary differentiation and divergence analysis of these genes remain to be explored. The current study used an integrated method to elucidate the sequential evolution of HSDs in 64 sequenced plant genomes. Analyses were conducted on their origins, distribution, duplication, evolutionary paths, domain functions, motif composition, properties, and cis-elements. Results indicate that except for algae, HSD1 was widely distributed in plant species ranging from lower to higher plants, while HSD5 was restricted to terrestrial plants, and HSD2 was identified in fewer monocots and several dicot plants. Phylogenetic analysis of HSD proteins revealed that monocotyledonous HSD1 in moss and ferns appeared closest to the outgroup, V. carteri HSD-like, M. musculus HSD1, and H. sapiens HSD1. These data support the hypothesis that HSD1 originated in bryophytes and then in non-vascular and vascular plants, followed by HSD5 only in land plants. Gene structure analysis suggests that HSDs in plant species came up with a fixed number of six exons, and the intron phase was primarily 0, 1, 0, 0, and 0. Similarly, duplication analysis revealed that segmental duplications were the main reason for HSDs in plant species. Physicochemical properties suggest that dicotyledonous HSD1s and HSD5s were mainly acidic. The monocotyledonous HSD1s and HSD2s and the dicotyledonous HSD2s, HSD3s, HSD4s, and HSD6s were mainly basic, implying that HSDs in plants may have a variety of functions. Cis-regulatory elements and expression analysis revealed that HSDs in plants might have roles in several abiotic stresses. Due to the high expression of HSD1s and HSD5s in seeds, these HSDs in plants may have roles in fatty acid accumulation and degradation.

Oil body (OB) mobilization, a crucial event associated with early seedling growth, is delayed in response to salt stress. Previous reports suggest that careful regulation of polyamine (PA) metabolism is essential for salt stress tolerance in plants. Many aspects of PA-mediated regulation of metabolism have been uncovered. However, their role in the process of OB mobilization remains unexplored. Interestingly, the present investigations reveal a possible influence of PA homeostasis on OB mobilization, while implicating complex regulation of oleosin degradation and aquaporin abundance in OB membranes in the process. Application of PA inhibitors resulted in the accumulation of smaller OBs when compared to control (-NaCl) and the salt-stressed counterparts, suggesting a faster rate of mobilization. PA deficit also resulted in reduced retention of some larger oleosins under controlled conditions but enhanced retention of all oleosins under salt stress. Additionally, with respect to aquaporins, a higher abundance of PIP2 under PA deficit both under control and saline conditions, is correlated with a faster mobilization of OBs. Contrarily, TIP1s, and TIP2s remained almost undetectable in response to PA depletion and were differentially regulated by salt stress. The present work, thus, provides novel insights into PA homeostasis-mediated regulation of OB mobilization, oleosin degradation, and aquaporin abundance on OB membranes.

New organelle acquisition through neofunctionalization of the endomembrane system (ES) with respect to plant secondary metabolism is a key evolutionary strategy for plant adaptation, which is overlooked due to the complexity of angiosperms. Bryophytes produce a broad range of plant secondary metabolites (PSMs), and their simple cellular structures, including unique organelles, such as oil bodies (OBs), highlight them as suitable model to investigate the contribution of the ES to PSMs. In this opinion, we review latest findings on the contribution of the ES to PSM biosynthesis, with a specific focus on OBs, and propose that the ES provides organelles and trafficking routes for PSM biosynthesis, transportation, and storage. Therefore, future research on ES-derived organelles and trafficking routes will provide essential knowledge for synthetic applications.

Oil bodies, also known as lipid droplets or oil droplets, are important organelles for oil storage in plant cells. The oil body is composed of a monolayer of phospholipid membrane encapsulating neutral fatty acids, and a variety of membrane proteins are embedded in the membrane, including oleosin, caleosin and steroleosin, of which oleosin accounts for 80%-90%. Oleosin plays important biological roles in various biological roles, such as affecting the size and stability of oil bodies, formation and degradation of oil bodies, lipid metabolism, and seed maturation and germination. In this review, we summarize the sequence and structural characteristics of oleosin and its important role in plant growth and development based on the research progress of plant oleosin gene families at home and abroad in recent years. Additionally, we discuss the application of oleosin in actual production and problems in the research and application, in order to provide a useful reference for people to further study the functions of oleosin-related molecules and their application in production practice.
油体也称脂滴或油滴，是植物细胞中一种重要的储藏油脂的细胞器。油体由单层磷脂膜包裹中性脂肪酸组成，膜上镶嵌有多种膜蛋白，包括油体蛋白、油体钙蛋白和油体固醇蛋白，其中油体蛋白占80%~90%。油体蛋白在影响油体大小与稳定性、油体形成和降解、脂质代谢、种子成熟及萌发等多种生命活动中都发挥着重要的生物学作用。本文结合近些年国内外关于植物油体蛋白基因家族的研究进展系统总结了油体蛋白序列与结构特征及在植物生长发育中所扮演的重要角色，讨论了油体蛋白作为一种新型植物蛋白在实际生产中的应用场景和油体蛋白研究及应用过程中仍存在的一些问题，以期为人们后期更加深入研究植物油体蛋白相关分子功能及在生产实践中应用提供有益的参考。.

Brassica napus is the most important oilseed crop in the world, and the lipid was stored in the oil body (OB) in the form of triacylglycerol. At present, most of studies on the relationship between oil body morphology and seed oil content in B. napus was focused on mature seeds. In the present study, the OBs in different developing seeds of B. napus with relatively high oil content (HOC) of about 50% and low oil content (LOC) of about 39% were analyzed. It was revealed that the size of OBs was first increased and then decreased in both materials. And in late seed developmental stages, the average OB size of rapeseed with HOC was higher than that of LOC, while it was reversed in the early seed developmental stages. No significant difference was observed on starch granule (SG) size in HOC and LOC rapeseed. Further results indicated that the expression of genes that involved in malonyl-CoA metabolism, fatty acid carbon chain extension, lipid metabolism, and starch synthesis in the rapeseed with HOC was higher than that of rapeseed with LOC. These results give some new insight for understanding the dynamics of OBs and SGs in embryos of B. napus.