Genome-Wide Identification of the Caffeoyl Coenzyme A 3-O-Methyltransferase Family Genes and Their Role in the Lodging Resistance of Wheat (Triticum aestivum L.)

As an enzyme, Caffeoyl coenzyme A 3-O-methyltransferase (CCoAOMT) plays a crucial role in lignin synthesis. In this study, we identified 21 TaCCoAOMTs in the wheat genome and, based on phylogenetic analysis, categorized them into four primary groups. TaCCoAOMTs within the same branch exhibited exon–intron structures and motif compositions similar to one another. Collinearity analysis showed that both segmental and tandem duplication contributed to the expansion of the TaCCoAOMT family in wheat. Several cis-elements associated with “growth and development” and “phytohormone response” were found in the promoter regions of TaCCoAOMTs. By analyzing TaCCoAOMT expression across tissues, we identified seven genes with significantly elevated expression in highly lignified tissues. We also compared TaCCoAOMT expression levels among four wheat varieties with varying degrees of lodging resistance. TaCCoAOMT10 and TaCCoAOMT18 exhibited significantly higher expression in lodging-resistant varieties than in susceptible ones and are therefore considered candidate genes associated with lodging resistance. Lodging-resistant varieties showed greater breaking strength and higher lignin content. These findings lay the groundwork for understanding TaCCoAOMT functions in wheat and for breeding programs aimed at improving lodging resistance.