Intergrative metabolomic and transcriptomic analyses reveal the potential regulatory mechanism of unique dihydroxy fatty acid biosynthesis in the seeds of an industrial oilseed crop Orychophragmus violaceus.

BACKGROUND: Orychophragmus violaceus is a potentially important industrial oilseed crop due to the two 24-carbon dihydroxy fatty acids (diOH-FA) that was newly identified from its seed oil via a 'discontinuous elongation' process. Although many research efforts have focused on the diOH-FA biosynthesis mechanism and identified the potential co-expressed diacylglycerol acyltranferase (DGAT) gene associated with triacylglycerol (TAG)-polyestolides biosynthesis, the dynamics of metabolic changes during seed development of O. violaceus as well as its associated regulatory network changes are poorly understood. RESULTS: In this study, by combining metabolome and transcriptome analysis, we identified that 1,003 metabolites and 22,479 genes were active across four stages of seed development, which were further divided into three main clusters based on the patterns of metabolite accumulation and/or gene expression. Among which, cluster2 was mostly related to diOH-FA biosynthesis pathway. We thus further constructed transcription factor (TF)-structural genes regulatory map for the genes associated with the flavonoids, fatty acids and diOH-FA biosynthesis pathway in this cluster. In particular, several TF families such as bHLH, B3, HD-ZIP, MYB were found to potentially regulate the metabolism associated with the diOH-FA pathway. Among which, multiple candidate TFs with promising potential for increasing the diOH-FA content were identified, and we further traced the evolutionary history of these key genes among species of Brassicaceae. CONCLUSION: Taken together, our study provides new insight into the gene resources and potential relevant regulatory mechanisms of diOH-FA biosynthesis uniquely in seeds of O. violaceus, which will help to promote the downstream breeding efforts of this potential oilseed crop and advance the bio-lubricant industry.

Fully biobased sustainable elastomers derived from chitin, lignin, and plant oil via grafting strategy and Schiff-base chemistry.

With the dramatically increased environmental problems, the rational design of sustainable polymers from renewable feedstocks opens new avenues to reduce the huge pollution impact. The major challenge for sustainable polymers is the decreased mechanical performance compared to that of petroleum-based materials. In this work, fully biobased sustainable elastomers were developed by integrating renewable chitin, lignin, and plant oil into one macromolecule, in which chitin was chosen as the rigid backbone, while a lignin-derived monomer vanillin acrylate (VA) and a plant oil-based monomer lauryl acrylate (LA) were selected as the hard and soft segments for the grafted side chains. A series of Chitin-graft-poly(vanillin acrylate-co-lauryl acrylate) (Chitin-g-P(VA-co-LA)) copolymers with varied feed ratios and chitin contents were synthesized by using reversible addition-fragmentation chain transfer (RAFT) polymerization as an effective grafting strategy. In addition, a dynamic cross-linked network was incorporated via Schiff-base reaction to improve the macroscopic behavior of such kind of chitin graft elastomers. These sustainable elastomers are mechanically strong and show excellent reprocessablity, as well as outstanding UV-blocking property. This strategy is versatile and can inspire the further development of fully biobased sustainable materials from natural resources.

Combination of cellulose and plant oil toward sustainable bottlebrush copolymer elastomers with tunable mechanical performance.

In this work, sustainable cellulose-g-poly(lauryl acrylate-co-acrylamide) [Cell-g-P(LA-co-AM)] bottlebrush copolymer elastomers derived from cellulose and plant oil were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Differential scanning calorimeter (DSC) results indicate that these thermally stable Cell-g-P(LA-co-AM) bottlebrush copolymer elastomers show adjustable melting temperatures. Monotonic and cyclic tensile tests suggest that the mechanical properties, including tensile strength, extensibility, Young's modulus, and elasticity, can be conveniently controlled by changing the LA/AM feed ratio and cellulose content. In such kind of bottlebrush copolymer elastomers, the rigid cellulose backbones act as cross-linking points to provide tensile strength. The incorporated PAM segments can form additional network structure via hydrogen bonding, resulting in enhanced tensile strength but decreased extensibility when more PAM segments are introduced. This versatile strategy can promote the development of sustainable cellulose-based bottlebrush copolymer elastomers from renewable resources.