Cloning and Functional Analysis of the FAD2 Gene Family from Desert Shrub Artemisia sphaerocephala

Abstract

Background: Linoleic acid is an important polyunsaturated fatty acid, required for all eukaryotes. Microsomal delta-12 (Δ12) oleate desaturase (FAD2) is a key enzyme for linoleic acid biosynthesis. Desert shrub Artemisia sphaerocephala is rich in linoleic acid, it has a large FAD2 gene family with twenty-six members. The objective of this work is to study the difference and potentially functionality of AsFAD2 family members. Results: Full-length cDNAs of twenty-one AsFAD2 genes were obtained from A. sphaerocephala. The putative polypeptides encoded by AsFAD2 family genes showed a high level of sequence similarity and were relatively conserved during evolution. The motif composition was relatively conservative. Quantitative real-time PCR analysis revealed that the AsFAD2-1 gene was strongly expressed in developing seeds, which may be closely associated with the high accumulating ability of linoleic acid in A. sphaerocephala seeds. Although different AsFAD2 family members showed diverse response to salt stress, the overall mRNA levels of the AsFAD2 family genes was stable, suggesting that the AsFAD2 family may play an important role in the adaptation of A. sphaerocephala to the harsh desert environment. Transient expression of AsFAD2 genes in the Nicotiana benthamiana leaves revealed that the encoded proteins were all located in the endoplasmic reticulum. Heterologous expression in Saccharomyces cerevisiae suggested that only three AsFAD2 enzymes, AsFAD2-1, -10, and -23, were Δ12 oleate desaturases, which could convert oleic acid to linoleic acid, whereas AsFAD2-1 and AsFAD2-10 could also produce palmitolinoleic acid. Conclusions: This research reported the cloning, expression studies, subcellular localization and functional identification of the large AsFAD2 gene family. These results should be helpful in understanding of fatty acid biosynthesis in A. sphaerocephala, and can be applied in the study of plant fatty acids traits.

Functional characterization and expression profile of microsomal FAD2 and FAD3 genes involved in linoleic and α-linolenic acid production in Leucas cephalotes

“…The expression of LcFAD2 gene was highest in developing seeds. Similar expression profiles of FAD2 gene were also noticed in various other plants (Xue et al 2017;Miao et al 2019). The high expression level in seeds indicates that LcFAD2 gene is involved in linoleic acid accumulation during storage lipid biosynthesis as the similar expression was also shown in Idesia polycarpa and Olea europaea (Fan et al 2019;Herna ´ndez et al 2005).…”

Identification, evolution, expression, and docking studies of fatty acid desaturase genes in wheat (Triticum aestivum L.)

“…Likewise, threes genes on chr2A (TaFAB2.1-3), chr2D (TaFAB2.9-11), chr5B (TaFAB 2. [26][27][28], and chr5A (TaFAB2. [23][24][25] are the result of tandem duplication.…”

“…The FAD2 members have been shown to play important roles in wheat response to environmental stresses. Microsomal omega-six fatty acid desaturases (FAD2) introduce a double bond to the oleic acid (C18:1) carbon chain resulting in linoleic acid (C18:2) [28]. Linoleic acid is a precursor of other polyunsaturated fatty acids, and it is essential for the growth of all eukaryotes [29].…”

Identification, Evolution, Expression, and Docking Studies of Fatty Acid Desaturase Genes in Wheat (Triticum aestivum L.)

“…Likewise, threes genes on chr2A (TaFAB2.1-3), chr2D (TaFAB2.9-11), chr5B (TaFAB2. [26][27][28], and chr5A (TaFAB2. [23][24][25] are the result of tandem duplication.…”

“…and TaFAD2.8 structural modeling and docking studies The FAD2 members have been shown to play important roles in wheat response to environmental stresses. Microsomal omega-six fatty acid desaturases (FAD2) introduce a double bond to the oleic acid (C18:1) carbon chain resulting in linoleic acid (C18:2)[28]. Linoleic acid is a precursor of other polyunsaturated fatty acids, and it is essential for the growth of all eukaryotes[29].…”