Transcriptome Analysis Provides Insights into Avenanthramide Biosynthesis in Oats under Methyl Jasmonate and Abscisic Acid Cotreatment

Avenanthramides are phenolic alkaloid derivatives uniquely found in oats (<i>Avena sativa</i> L.). We conducted transcriptomic analysis to investigate the global changes of gene expression in oat seedlings cotreated with methyl jasmonate (MJ) and abscisic acid (ABA). The cotreatment significantly enhanced avenanthramide accumulation in oat seedlings, reaching 1171.7 mg/kg fresh weight, representing a 5.5-fold increase compared to the 4 day control sample (221.5 mg/kg FW). A total of 4841 genes were differentially expressed, including 1921 upregulated and 2920 downregulated genes compared to untreated controls. Co-treatment upregulated genes encoding phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), caffeoyl-CoA <i>O</i>-methyltransferase (CCoAOMT), and hydroxycinnamoyl-CoA:hydroxyanthranilate <i>N</i>-hydroxycinnamoyl transferase (HHT) enzymes, along with 98 transcription factors from MYB, bHLH, HSF, WRKY, bZIP, and ERF families. These results suggest that MJ and ABA cotreatment modulates the expression of key biosynthetic and regulatory genes involved in avenanthramide production in oat seedlings, offering valuable insights for enhancing the nutraceutical value of oats.