关键词: 蒙古冰草, 肉桂醇脱氢酶, 木质素, 抗逆性

Abstract: As an essential enzyme in plant secondary metabolism, cinnamyl alcohol dehydrogenase (CAD) plays a key role in regulating plant growth and development, as well as biological/abiotic stress resistance. Agropyron mongolicum is a traditional forage grass widely distributed in the desert grassland areas of northern China, which exhibited high tolerance to drought and cold stress. To explore the role of cinnamyl alcohol dehydrogenase in Agropyron mongolicum, in this study, a CAD gene was identified from the full-length transcriptome data of Agropyron mongolicum and subsequentially analyzed in vitro. The 1 083 bp coding sequence of AmCAD encodes 361 amino acids, which has typical conserved CAD region containing two Zn²⁺ binding motifs and NADP (H) cofactor binding motifs. AmCAD is highly expressed in the stem. The AmCAD recombinant protein showed a robust catalytic ability to different cinnamaldehyde substrates, with the highest substrate affinity of coniferyl aldehyde. Under drought stress, the expression level of AmCAD was significantly induced, indicating a potential function of this gene in stress tolerance. The experimental results indicate that AmCAD may play an important role in lignin biosynthesis and drought stress tolerance in Agropyron mongolicum. Our research provided potentially valuable genetic resources for molecular breeding of Agropyron mongolicum to improve biomass quality and stress resistance.