Proteomic analysis of metabolic mechanisms associated with fatty acid biosynthesis during Styrax tonkinensis kernel development

Abstract

BACKGROUND: Styrax tonkinensis is a white-flowered tree with considerable potential as a feedstock source for biodiesel production from the oily seed contained within its nutlike drupes. Transcriptome changes during oil accumulation have been previously reported, but not concurrent changes in the proteome. RESULTS: Using proteomic analysis of samples collected at 50, 70, 100 and 130 days after flowering (DAF), we identified 1472 differentially expressed proteins (DEPs). Based on their expression patterns, we grouped the DEPs into nine clusters and analyzed the pathway enrichment. Proteins related to starch and sucrose metabolism were most abundant at 50 DAF. Proteins involved in fatty acid (FA) biosynthesis were mainly grouped into a cluster that peaked at 70 DAF. Proteins related to protein processing in endoplasmic reticulum had two major patterns, trending either upwards or downwards, while proteins involved in amino acid biosynthesis showed more complex relationships. We identified 42 key enzymes involved in lipid accumulation during kernel development, including the acetyl-CoA carboxylase complex (ACC) and the pyruvate dehydrogenase complex (PDC). One oil body membrane protein, oleosin, continuously increased during kernel development.CONCLUSION: A regulatory network of oil accumulation processes was built based on protein and available transcriptome expression data, which were in good temporal agreement. This analysis placed ACC and PDC in the center of the network, suggesting that the glycolytic provision of substrate plays a central regulatory role in FA biosynthesis and oil accumulation.

Effects of Fruit Shading on Gene and Protein Expression During Starch and Oil Accumulation in Developing Styrax tonkinensis Kernels

“…All the replicates from FSK and CK groups clustered together respectively, indicating that S. tonkinensis kernel biological processes at the protein level changed significantly with fruit shading. The number of proteins identified in this study (3,181) was more than that (2,338) in the proteome analysis of S. tonkinensis kernel samples from different time points ( Wu et al, 2021 ), which may be due to the gradual formation of proteins during kernel development, such as the proteins related to TAG formation in ER. All the 227 DEPs were downregulated in the FSK group, indicating that fruit shading inhibited S. tonkinensis kernel development by reducing photosynthesis in the pericarp and decreasing carbon source flow into kernels ( Zhang et al, 2018 ; Wu et al, 2019b ).…”

“…Kernels collected from FSK and CK groups at 80 DAF were used for proteomic analysis, again with four biological replicates per treatment. Protein extraction and digestion were performed according to our previous study ( Wu et al, 2021 ). The peptide mixture resulting from trypsin digestion was labeled using an 8-plex iTRAQ kit (AB Sciex, Framingham, United States) following the manufacturer’s instructions and Ye et al (2010) .…”

“…Re-dissolved peptides were analyzed by Nano-HPLC-MS/MS using an EASY nLC 1,000 system (Waters Corporation, Milford, United States) coupled to a Q-Exactive mass spectrometer (Thermo Fisher Scientific, Waltham, United States). The parameter settings were as described by our previous study ( Wu et al, 2021 ).…”

“…Mechanisms of oil accumulation have been analyzed at the molecular level using transcriptomic and proteomic methods in many oilseed plants, including Elaeis guineensis ( Bourgis et al, 2011 ; Silva et al, 2014 ), Vernicia fordii ( Zhang et al, 2014 ; Zhan et al, 2016 ), Jatropha curcas ( Grover et al, 2014 ; Liu et al, 2015 ) and S. tonkinensis ( Wu et al, 2020 , 2021 ). In our previous studies, ACC and PDC were placed in the center of the regulatory network for oil accumulation during S. tonkinensis kernel development ( Wu et al, 2020 , 2021 ). However, at the protein level, the biological functioning of TAG-related enzymes, such as DGAT and PDAT, is unclear, as these endoplasmic reticulum-associated proteins appear at middle stages during kernel development ( Wiese et al, 2007 ; Liu et al, 2018 ).…”

The Combined Analysis of Transcriptome and Antioxidant Enzymes Revealed the Mechanism of EBL and ZnO NPs Enhancing Styrax tonkinensis Seed Abiotic Stress Resistance

“…S. tonkinensis , a member of the Styracaceae family of deciduous trees, is primarily found in Southeast Asia, including Vietnam and China [ 18 ]. The seeds of S. tonkinensis have high oil content, and their seed oil meets US, German, EU, and Chinese biodiesel standards [ 19 , 20 ]. The resin of S. tonkinensis is used as perfume and medicine and has high potential economic value [ 21 , 22 ].…”