Identification of genes associated with the biosynthesis of unsaturated fatty acid and oil accumulation in herbaceous peony ‘Hangshao’ (Paeonia lactiflora ‘Hangshao’) seeds based on transcriptome analysis

Abstract

Background Paeonia lactiflora ‘Hangshao’ is widely cultivated in China as a traditional Chinese medicine ‘Radix Paeoniae Alba’. Due to the abundant unsaturated fatty acids in its seed, it can also be regarded as a new oilseed plant. However, the process of the biosynthesis of unsaturated fatty acids in it has remained unknown. Therefore, transcriptome analysis is helpful to better understand the underlying molecular mechanisms. Results Five main fatty acids were detected, including stearic acid, palmitic acid, oleic acid, linoleic acid and α-linolenic acid, and their absolute contents first increased and then decreased during seed development. A total of 150,156 unigenes were obtained by transcriptome sequencing. There were 15,005 unigenes annotated in the seven functional databases, including NR, NT, GO, KOG, KEGG, Swiss-Prot and InterPro. Based on the KEGG database, 1766 unigenes were annotated in the lipid metabolism. There were 4635, 12,304, and 18,291 DEGs in Group I (60 vs 30 DAF), Group II (90 vs 60 DAF) and Group III (90 vs 30 DAF), respectively. A total of 1480 DEGs were detected in the intersection of the three groups. In 14 KEGG pathways of lipid metabolism, 503 DEGs were found, belonging to 111 enzymes. We screened out 123 DEGs involved in fatty acid biosynthesis (39 DEGs), fatty acid elongation (33 DEGs), biosynthesis of unsaturated fatty acid (24 DEGs), TAG assembly (17 DEGs) and lipid storage (10 DEGs). Furthermore, qRT-PCR was used to analyze the expression patterns of 16 genes, including BBCP, BC, MCAT, KASIII, KASII, FATA, FATB, KCR, SAD, FAD2, FAD3, FAD7, GPAT, DGAT, OLE and CLO, most of which showed the highest expression at 45 DAF, except for DGAT, OLE and CLO, which showed the highest expression at 75 DAF. Conclusions We predicted that MCAT, KASIII, FATA, SAD, FAD2, FAD3, DGAT and OLE were the key genes in the unsaturated fatty acid biosynthesis and oil accumulation in herbaceous peony seed. This study provides the first comprehensive genomic resources characterizing herbaceous peony seed gene expression at the transcriptional level. These data lay the foundation for elucidating the molecular mechanisms of fatty acid biosynthesis and oil accumulation for herbaceous peony.

Cut peony industry: the first 30 years of research and new horizons

“…Biochemical and molecular research contributes to better understanding and possible regulation of developmental traits, from stress tolerance [ 60 , 61 ] to flower color [ 62 , 63 ] and biosynthesis of secondary metabolites [ 64 ]. Currently, the first priority for genetic research should be introduction of disease resistance to new cultivars, and recent reports confirm possibility of this direction [ 65 – 67 ].…”

Kinetics of seed reserve compounds during the maturation of herbaceous peony (Paeonia lactiflora Pall.) seeds

“…The determination of starch content was conducted according to the instructions of plant starch content reagent kit (Shanghai Cableridge Biotechnology Co., LTD.). The extraction of crude fat was conducted according to Meng et al (2021). And the crude fat content was calculated by the following formula C f (mg/g) = 1000 × (W 1 -W 0 ) / W 2 .…”

“…Fatty acid composition analysis and content determination mainly includes the following steps such as standard solution preparation, sample hydrolysis, fat extraction, fatty acid esterification, gas chromatographic and mass spectrometric (GC-MS) parameter setting, and calculation for the fatty acid absolute content. The specific methods were referred to previous description (Meng et al, 2021).…”

“…The focus of our study was Paeonia lactiflora 'Hangshao', one of the main cultivars used for medical propose. This cultivar produces a large number of seeds each year (Meng et al, 2018). However, only a small number of seeds are used for propagation (Choi et al, 2009), and most of them are abandoned, which cause a huge waste of resources.…”

Integrated Lipidomic and Transcriptomic Analysis Reveals Lipid Metabolism in Foxtail Millet (Setaria italica)

“… Fei et al (2020) employed transcriptome sequencing and RT-qPCR to determine the expression levels of 20 genes related to fatty acid synthesis in Zanthoxylum bungeanum seeds, the results of intergroup correlation and RDA analysis suggested that ENR , ECR , and SAD1 are the key genes in fatty acid synthesis. Meng et al (2021) used transcriptomics to predict the key genes of unsaturated fatty acid (UFA) synthesis and oil accumulation in Paeonia lactiflora seeds, including MCAT , KASIII , FATA , SAD , FAD2 , FAD3 , and DGAT , providing more comprehensive genomic resources for understanding the transcription of genes in P. lactiflora seeds.…”