Endoplasmic reticulum retention signaling and transmembrane channel proteins predicted for oilseed ω3 fatty acid desaturase 3 (FAD3) genes

AhFAD3-A01 enhances α-linolenic acid content in Arabidopsis and peanut

Alpha-linolenic acid (ALA, C18:3) is an essential fatty acid integral to human growth and development. Despite its significance, the ALA content in peanut seeds-a major global oilseed crop-is notably low. This study employed bioinformatics analysis, tissue expression, and promoter function evaluations to investigate AhFAD3, which encodes the microsomal omega-3 fatty acid desaturase that is directly responsible for ALA accumulation through converting linoleic acid (LA) to ALA. We identified the active AhFAD3 gene, AhFAD3-A01, with the functional protein encoded by AhFAD3-A01 localized in the endoplasmic reticulum (ER) and found to be pivotal in ALA synthesis in seeds. The low expression of AhFAD3 genes during the late stages of seed development, coupled with the specific activation by only AhFAD3-A01 and AhFAD3-B01 promoters in seeds, results in the low ALA levels in mature peanut seeds. To enhance ALA content, the constitutive promoter CaMV35S and the seed-specific promoter PAhWRI1 were utilized to overexpress AhFAD3-A01 in Arabidopsis and peanut. While the expression level of AhFAD3-A01 in PAhWRI1::AhFAD3-A01 transgenic Arabidopsis remained unchanged, it significantly increased under the CaMV35S::AhFAD3-A01 configuration, leading to an over a 40 % increase in ALA content of in T4 generation seeds, indicating that PAhWRI1 was unable to drive AhFAD3 overexpression in Arabidopsis. Similarly, the overexpression of AhFAD3-A01 using both promoters in peanuts resulted in enhanced expression and an increase in ALA content from 15.18 % to 30.65 % in CaMV35S::AhFAD3-A01 T1 generation seeds and from 11.23 % to 25.49 % in PAhWRI1::AhFAD3-A01 seeds. These results highlight the critical role of AhFAD3-A01 ALA synthesis in peanut seeds and provide a solid foundation for developing peanut varieties with elevated ALA content.

Fatty Acid Desaturase Bmdesat5, Suppressed in the Salivary Glands by Domestication, is Involved in Regulation of Food Intake in Silkworms

Understanding the evolutionary genetics of food intake regulation in domesticated animals has relevance to evolutionary biology, animal improvement, and obesity treatment. Here, we observed that the fatty acid desaturase gene (Bmdesat5), which regulates food intake, is suppressed in domesticated silkworms, but expressed in the salivary glands of the wild silkworm Bombyx mandarina. The content of its catalytic product, cis-vaccenic acid, was related to the expression levels of Bmdesat5 in the salivary glands of domesticated and wild silkworm strains. These two strains also showed significant differences in food intake. Using orally administering cis-vaccenic acid and transgenic-mediated overexpression, we verified that cis-vaccenic acid functions as a satiation signal, regulating food intake and growth in silkworms. Selection analysis showed that Bmdesat5 experienced selection, especially in the potential promoter, 5'-untranslated, and intron regions. This study highlights the importance of the decrement of satiety in silkworm domestication and provides new insights into the potential involvement of salivary glands in the regulation of satiety in animals, by acting as a supplement to gut-brain nutrient signaling.

GhFAD3-4 Promotes Fiber Cell Elongation and Cell Wall Thickness by Increasing PI and IP3 Accumulation in Cotton

The omega-3 fatty acid desaturase enzyme gene FAD3 is responsible for converting linoleic acid to linolenic acid in plant fatty acid synthesis. Despite limited knowledge of its role in cotton growth, our study focused on GhFAD3-4, a gene within the FAD3 family, which was found to promote fiber elongation and cell wall thickness in cotton. GhFAD3-4 was predominantly expressed in elongating fibers, and its suppression led to shorter fibers with reduced cell wall thickness and phosphoinositide (PI) and inositol triphosphate (IP3) levels. Transcriptome analysis of GhFAD3-4 knock-out mutants revealed significant impacts on genes involved in the phosphoinositol signaling pathway. Experimental evidence demonstrated that GhFAD3-4 positively regulated the expression of the GhBoGH3B and GhPIS genes, influencing cotton fiber development through the inositol signaling pathway. The application of PI and IP6 externally increased fiber length in GhFAD3-4 knock-out plants, while inhibiting PI led to a reduced fiber length in GhFAD3-4 overexpressing plants. These findings suggest that GhFAD3-4 plays a crucial role in enhancing fiber development by promoting PI and IP3 biosynthesis, offering the potential for breeding cotton varieties with superior fiber quality.

Fatty acid desaturases (FADs) modulate multiple lipid metabolism pathways to improve plant resistance

BACKGROUND

Biological and abiotic stresses such as salt, extreme temperatures, and pests and diseases place major constraints on plant growth and crop yields. Fatty acids (FAs) and FA- derivatives are unique biologically active substance that show a wide range of functions in biological systems. They are not only participated in the regulation of energy storage substances and cell membrane plasm composition, but also extensively participate in the regulation of plant basic immunity, effector induced resistance and systemic resistance and other defense pathways, thereby improving plant resistance to adversity stress. Fatty acid desaturases (FADs) is involved in the desaturation of fatty acids, where desaturated fatty acids can be used as substrates for FA-derivatives.

OBJECTIVE

In this paper, the role of omega-FADs (ω-3 FADs and ω-6 FADs) in the prokaryotic and eukaryotic pathways of fatty acid biosynthesis in plant defense against stress (biological and abiotic stress) and the latest research progress were summarized. Moreover' the existing problems in related research and future research directions were also discussed.

RESULTS

Fatty acid desaturases are involved in various responses of plants during biotic and abiotic stress. For example, it is involved in regulating the stability and fluidity of cell membranes, reactive oxygen species signaling pathways, etc. In this review, we have collected several experimental studies to represent the differential effects of fatty acid desaturases on biotic and abiotic species.

CONCLUSION

Fatty acid desaturases play an important role in regulating biotic and abiotic stresses.

Towards engineered yeast as production platform for capsaicinoids

Capsaicinoids are bioactive alkaloids produced by the chili pepper fruit and are known to be the most potent agonists of the human pain receptor TRPV1 (Transient Receptor Potential Cation Channel Subfamily V Member 1). They are currently produced by extraction from chili pepper fruit or by chemical synthesis. Transfer of the biosynthetic route to a microbial host could enable more efficient capsaicinoid production by fermentation and may also enable the use of synthetic biology to create a diversity of new compounds with potentially improved properties. This review summarises the current state of the art on the biosynthesis of capsaicinoid precursors in baker's yeast, Saccharomyces cerevisiae, and discusses bioengineering strategies for achieving total synthesis from sugar.

How salt stress-responsive proteins regulate plant adaptation to saline conditions

An overview is presented of recent advances in our knowledge of candidate proteins that regulate various physiological and biochemical processes underpinning plant adaptation to saline conditions. Salt stress is one of the environmental constraints that restrict plant distribution, growth and yield in many parts of the world. Increased world population surely elevates food demands all over the globe, which anticipates to add a great challenge to humanity. These concerns have necessitated the scientists to understand and unmask the puzzle of plant salt tolerance mechanisms in order to utilize various strategies to develop salt tolerant crop plants. Salt tolerance is a complex trait involving alterations in physiological, biochemical, and molecular processes. These alterations are a result of genomic and proteomic complement readjustments that lead to tolerance mechanisms. Proteomics is a crucial molecular tool that indicates proteins expressed by the genome, and also identifies the functions of proteins accumulated in response to salt stress. Recently, proteomic studies have shed more light on a range of promising candidate proteins that regulate various processes rendering salt tolerance to plants. These proteins have been shown to be involved in photosynthesis and energy metabolism, ion homeostasis, gene transcription and protein biosynthesis, compatible solute production, hormone modulation, cell wall structure modification, cellular detoxification, membrane stabilization, and signal transduction. These candidate salt responsive proteins can be therefore used in biotechnological approaches to improve tolerance of crop plants to salt conditions. In this review, we provided comprehensive updated information on the proteomic data of plants/genotypes contrasting in salt tolerance in response to salt stress. The roles of salt responsive proteins that are potential determinants for plant salt adaptation are discussed. The relationship between changes in proteome composition and abundance, and alterations observed in physiological and biochemical features associated with salt tolerance are also addressed.

Molecular and Biochemical Evaluation of Ethyl Methanesulfonate-Induced Mutant Lines in Camelina sativa L

Background

Camelina sativa is one of the most important oilseeds that has a proportionate profile of essential unsaturated fatty acids that are suitable for human nutrition. In this regard, we can mention a high percentage and a reasonable ratio of omega 3 and omega 6.

Objectives

In the current study, the created variation of second-generation mutant (M2) camelina lines in terms of fatty acid profiles and ISSR molecular markers in C. sativa was evaluated.

Materials and Methods

For this purpose, while producing the first-generation of mutant plants (M1), 200 M2 seeds with 0.1% and 0.5% ethyl methanesulfonate (EMS) mutations were treated in two replications for 8 and 16 hours based on a completely randomized design.

Results

The results of mean comparisons showed that there was no significant difference between treatments in terms of fatty acids of palmitic acid, stearic acid, linoleic acid, eicosadienoic acid, oleic acid and erucic acid. The cluster analysis revealed that all the treatments used with five replications were divided into eight groups. It was found that all replications of the treatment with a concentration of 0.1% and a time of 16 hours (C1T2) were in the second group with the lowest palmitic acid was present among other treatments. Therefore, C1T2 treatment is recommended as the best treatment to reduce palmitic acid. Examination of the information content of ISSR molecular markers also showed that markers 2, 5, and 6 were the best informative markers in the detection of camelina fatty acid profiles.

Conclusion

A significant variation has been created in the fatty acids profile and it can be applied in future breeding programs depending on the intended purpose.

Characterization of genes encoding ω-6 desaturase PoFAD2 and PoFAD6, and ω-3 desaturase PoFAD3 for ALA accumulation in developing seeds of oil crop Paeonia ostii var. lishizhenii

Paeonia ostii var. lishizhenii has emerged as a valuable oil-producing crop with splendid characteristic of high α-linolenic acid (C18:3, ALA) content in its seed oil for healthy food supplement, but the molecular mechanism for seed ALA accumulation remains enigmatic. In our previous report, a PoSAD gene encoding stearoyl-ACP desaturase had been cloned and functional charactered for the first desaturation procedure involved in ALA biosynthesis pathway in P. ostii var. lishizhenii endosperms, while other participants have not been identified to date. In this study, full-length cDNAs of PoFAD2 (1489 bp), PoFAD6 (1638 bp), and PoFAD3 (1709 bp) were isolated based on our recent transcriptome sequencing data. Bioinformatic analyses revealed that the PoFADs were closest to their counterparts from Paeoniaceae species P. ludlowii, P. rockii, and P. suffruticosa in phylogenetic tree, which shared highly conserved histidine boxes (HXXXH, HXXHH, and HXXHH), exhibiting typical characters of membrane-bound desaturases in higher plants. Additionally, the PoFAD2 and PoFAD3 were specifically expressed and highly associated with LA and ALA accumulation in developing endosperms, whereas PoFAD6 expression has no significantly difference during whole seed developing stages. The catalytic function of these PoFADs were further analyzed by heterologous expression in Saccharomyces cerevisiae and Arabidopsis thaliana. The results showed that PoFAD2 and PoFAD6 could catalyze linoleic acid (C18:2) synthesis, while PoFAD3 had ability to produce ALA. This study functional identified three PoFAD genes, which indicates their critical roles in ALA biosynthesis pathway in P. ostii var. lishizhenii, and is of great theoretical and practical meaning on breeding and cultivating new tree peony varieties to promote human health and nutrition supplement.