Bioinformatics Identification and Expression Analysis of Acetyl-CoA Carboxylase Reveal Its Role in Isoflavone Accumulation during Soybean Seed Development

Isoflavones belong to the class of flavonoid compounds, which are important secondary metabolites that play a crucial role in plant development and defense. Acetyl-CoA carboxylase (ACCase) is a biotin-dependent enzyme that catalyzes the conversion of Acetyl-CoA into Malonyl-CoA in plants. It is a key enzyme in fatty acid synthesis and also catalyzes the production of various secondary metabolites. However, information on the <i>ACC</i> gene family in the soybean (<i>Glycine max</i> L. Merr.) genome and the specific members involved in isoflavone biosynthesis is still lacking. In this study, we identified 20 <i>ACC</i> family genes (<i>GmACCs</i>) from the soybean genome and further characterized their evolutionary relationships and expression patterns. Phylogenetic analysis showed that the <i>GmACCs</i> could be divided into five groups, and the gene structures within the same groups were highly conserved, indicating that they had similar functions. The <i>GmACCs</i> were randomly distributed across 12 chromosomes, and collinearity analysis suggested that many <i>GmACCs</i> originated from tandem and segmental duplications, with these genes being under purifying selection. In addition, gene expression pattern analysis indicated that there was functional divergence among <i>GmACCs</i> in different tissues. The <i>GmACCs</i> reached their peak expression levels during the early or middle stages of seed development. Based on the transcriptome and isoflavone content data, a weighted gene co-expression network was constructed, and three candidate genes (<i>Glyma.06G105900</i>, <i>Glyma.13G363500</i>, and <i>Glyma.13G057400</i>) that may positively regulate isoflavone content were identified. These results provide valuable information for the further functional characterization and application of <i>GmACCs</i> in isoflavone biosynthesis in soybean.