Transcriptomic Analysis Reveals Key Genes Involved in Oil and Linoleic Acid Biosynthesis during Artemisia sphaerocephala Seed Development.

Shuzhen Nan,Xiaowei Hu,Xiumei Miao,Xiaoxu Han,Hua Fu,Lijing Zhang

doi:10.3390/ijms22168369

Abstract

Artemisia sphaerocephala seeds are rich in polysaccharides and linoleic acid (C18:2), which have been widely used as traditional medicine and to improve food quality. The accumulation patterns and molecular regulatory mechanisms of polysaccharides during A. sphaerocephala seed development have been studied. However, the related research on seed oil and C18:2 remain unclear. For this study, A. sphaerocephala seeds at seven different development stages at 10, 20, 30, 40, 50, 60, and 70 days after flowering (designated as S1~S7), respectively, were employed as experimental samples, the accumulation patterns of oil and fatty acids (FA) and the underlying molecular regulatory mechanisms were analyzed. The results revealed that oil content increased from 10.1% to 20.0% in the early stages of seed development (S1~S2), and up to 32.0% in mature seeds, of which C18:2 accounted for 80.6% of the total FA. FA and triacylglycerol biosynthesis-related genes jointly involved in the rapid accumulation of oil in S1~S2. Weighted gene co-expression network analysis showed that transcription factors FUS3 and bHLH played a critical role in the seed oil biosynthesis. The perfect harmonization of the high expression of FAD2 with the extremely low expression of FAD3 regulated the accumulation of C18:2. This study uncovered the gene involved in oil biosynthesis and molecular regulatory mechanisms of high C18:2 accumulation in A. sphaerocephala seeds; thus, advancing research into unsaturated fatty acid metabolism in plants while generating valuable genetic resources for optimal C18:2 breeding.

Highlights

Vegetable oils are an important component of the human diet that provide energy, as well as a variety of fatty acids (FAs) required to maintain optimal health
The oil content of A. sphaerocephala seeds continuously increased from 10.1% to 32.0% with seed development (Figure 1D), which was higher than G. max (~20%) and Zea mays (6.7%) [3,32], but lower than B. napus (42.7%), A. hypogaea (53.8%), and sesame (Sesamum indicum)
The high expression of FA de novo biosynthesis-related genes, encompassed acetyl-CoA carboxylase (ACCase), malonyl-CoA ACP Smalonytransferase (MAT), ketoacyl-ACP synthase (KAS), ketoacyl-ACP reductase (KAR), enoyl-ACP reductase (EAR), hydroxyacyl-ACP dehydratase (HAD), and TAG biosynthesis-related genes, including glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferase (LPAT), lysophosphatidylcholine acyltransferase (LPCAT), PLA2 during S1~S2, which was crucial for the rapid accumulation of oil in the early seed development stages

Summary

Introduction

Vegetable oils are an important component of the human diet that provide energy, as well as a variety of fatty acids (FAs) required to maintain optimal health. Linoleic acid (C18:2, LA) is an essential FA that cannot be synthesized in vivo by humans and mammals; it must be obtained from the diet. C18:2 and CLA play critical roles in the prevention of cancer and various cardiovascular, inflammatory, and autoimmune diseases [1,2]. Seeds are important storage organs for vegetable oils, which are primarily stored as triacylglycerols (TAG), with variable content in different plant species. The accumulation of seed oil is a complex process, which primarily consists of two parts: FA de novo biosynthesis in plastids and TAG biosynthesis in endoplasmic reticulum (ER) [8,9]

Methods

Results

Conclusion