Oil crop genetic modification for producing added value lipids

Identification of High Linoleic Acid Varieties in Tetraploid perilla through Gamma-ray Irradiation and CRISPR/Cas9

Perilla [Perilla frutescens (L.) var frutescens] is a traditional oil crop in Asia, recognized for its seeds abundant in α-linolenic acid (18:3), a key omega-3 fatty acid known for its health benefits. Despite the known nutritional value, the reason behind the higher 18:3 content in tetraploid perilla seeds remained unexplored. Gamma irradiation yielded mutants with altered seed fatty acid composition. Among the mutants, DY-46-5 showed a 27% increase in 18:2 due to the 4-bp deletion of PfrFAD3b, and NC-65-12 displayed a 16% increase in 18:2 due to the loss of function of PfrFAD3a through a large deletion. Knocking out both copies of FATTY ACID DESATURASE3 (PfrFAD3a and PfrFAD3b) simultaneously using CRISPR/Cas9 resulted in an increase in 18:2 by up to 75% and a decrease in 18:3 to as low as 0.3% in seeds, emphasizing the pivotal roles of both genes in 18:3 synthesis in tetraploid perilla. Furthermore, diploid Perilla citriodora, the progenitor of cultivated tetraploid perilla, harbors only PfrFAD3b, with a fatty acid analysis revealing lower 18:3 levels than tetraploid perilla. In conclusion, the enhanced 18:3 content in cultivated tetraploid perilla seeds can be attributed to the acquisition of two FAD3 copies through hybridization with wild-type diploid perilla.

Biological Roles of Lipids in Rice

Lipids are organic nonpolar molecules with essential biological and economic importance. While the genetic pathways and regulatory networks of lipid biosynthesis and metabolism have been extensively studied and thoroughly reviewed in oil crops such as soybeans, less attention has been paid to the biological roles of lipids in rice, a staple food for the global population and a model species for plant molecular biology research, leaving a considerable knowledge gap in the biological roles of lipids. In this review, we endeavor to furnish a current overview of the advancements in understanding the genetic foundations and physiological functions of lipids, including triacylglycerol, fatty acids, and very-long-chain fatty acids. We aim to summarize the key genes in lipid biosynthesis, metabolism, and transcriptional regulation underpinning rice's developmental and growth processes, biotic stress responses, abiotic stress responses, fertility, seed longevity, and recent efforts in rice oil genetic improvement.

A comprehensive review on oleaginous bacteria: an alternative source for biodiesel production

Due to continuously increasing population, industrialization, and environmental pollution, lead to generating high energy demand which suitable for our environment. Biodiesel is an alternative renewable fuel source. According to the feedstock of production, biodiesel has been categorized into four generations. The main disadvantage of the first and second generation is the raw material processing cost that the challenge for its industrial-level production. Oleaginous bacteria that contain more than 20% lipid of their cellular biomass can be a good alternative and sustainable feedstock. Oleaginous bacteria used as feedstock have numerous advantages, such as their high growth rate, being easy to cultivate, utilizing various substrates for growth, genetic or metabolic modifications possible. In addition, some species of bacteria are capable of carbon dioxide sequestration. Therefore, oleaginous bacteria can be a significant resource for the upcoming generation's biodiesel production. This review discusses the biochemistry of lipid accumulation, screening techniques, and lipid accumulation factors of oleaginous bacteria, in addition to the overall general biodiesel production process. This review also highlights the biotechnological approach for oleaginous bacteria strain improvement that can be future used for biodiesel production and the advantages of using general biodiesel in place of conventional fuel, along with the discussion about global policies and the prospect that promotes biodiesel production from oleaginous bacteria.

Asymmetric syntheses of four stereoisomers of 13-hydroxy-14-methylhexadecanoic acid as potential antibacterial agents

The first total syntheses of four stereoisomers of 13-hydroxy-14-methylhexadecanoic acid have been accomplished. Central to this strategy are asymmetric alkynylation of aldehyde, acid-catalyzed lactonization, the selective protection of primary alcohol and Wittig reaction. The product 1a was obtained in 17 steps in 2% overall yield. Moreover, these synthetic chiral hydroxy fatty acids 1a-1d are valuable for the development of antibacterial agents.

Lipases of germinating jojoba seeds efficiently hydrolyze triacylglycerols and wax esters and display wax ester-synthesizing activity

BACKGROUND

Simmondsia chinensis (jojoba) is the only plant known to store wax esters instead of triacylglycerols in its seeds. Wax esters are composed of very-long-chain monounsaturated fatty acids and fatty alcohols and constitute up to 60% of the jojoba seed weight. During jojoba germination, the first step of wax ester mobilization is catalyzed by lipases. To date, none of the jojoba lipase-encoding genes have been cloned and characterized. In this study, we monitored mobilization of storage reserves during germination of jojoba seeds and performed detailed characterization of the jojoba lipases using microsomal fractions isolated from germinating seeds.

RESULTS

During 26 days of germination, we observed a 60-70% decrease in wax ester content in the seeds, which was accompanied by the reduction of oleosin amounts and increase in glucose content. The activity of jojoba lipases in the seed microsomal fractions increased in the first 50 days of germination. The enzymes showed higher activity towards triacylglycerols than towards wax esters. The maximum lipase activity was observed at 60 °C and pH around 7 for triacylglycerols and 6.5-8 for wax esters. The enzyme efficiently hydrolyzed various wax esters containing saturated and unsaturated acyl and alcohol moieties. We also demonstrated that jojoba lipases possess wax ester-synthesizing activity when free fatty alcohols and different acyl donors, including triacylglycerols and free fatty acids, are used as substrates. For esterification reactions, the enzyme utilized both saturated and unsaturated fatty alcohols, with the preference towards long chain and very long chain compounds.

CONCLUSIONS

In in vitro assays, jojoba lipases catalyzed hydrolysis of triacylglycerols and different wax esters in a broad range of temperatures. In addition, the enzymes had the ability to synthesize wax esters in the backward reaction. Our data suggest that jojoba lipases may be more similar to other plant lipases than previously assumed.