エンバク（Avena sativa L.）基部第二節間における耐倒伏性分子基盤の統合的トランスクリプトーム・メタボローム解剖

Oat (Avena sativa L.) is an important grain and feed crop, playing a significant role in agricultural production. However, lodging remains a key factor limiting oat yield and quality. Recent advances in molecular biology have shed light on the mechanisms of oat lodging resistance, particularly highlighting the critical role of lignin and cellulose content in stem strength. Nevertheless, the molecular regulatory networks governing lignin and cellulose biosynthesis in the basal second internode remain poorly understood.

In this study, we conducted a comprehensive analysis of phenotypic traits, lignin and cellulose content, and transcriptomic and metabolomic profiles in the basal second internode of two contrasting oat cultivars of lodging-resistant MY1 and lodging-susceptible DY2 during the filling, milk, and dough stages. Both MY1 and DY2 showed the highest levels of lignin and cellulose at milk stage, and MY1 maintained significantly higher lignin and cellulose content compared to DY2 at all developmental stages (P < 0.05). In addition, a total of 8,116 differentially expressed genes (DEGs) and 4,374 metabolites were identified. Our results identified six key genes involved in lignin synthesis (4CL3, CAD6, HRPA2, CCOAOMT, CCR1, PRX112) and five associated metabolites (L-phenylalanine, sinapropyl alcohol, sinapic acid, ferulic acid, coniferyl alcohol), as well as two cellulose synthesis-related genes (CESA4, CESA9) and one metabolite (uridine diphosphate glucose). These genes and metabolites were mainly highly expressed and enriched in MY1 during the milk stage, suggesting their potential role in enhancing lodging resistance.

Our integrated phenotypic traits, lignin and cellulose content, and transcriptomic and metabolomic analysis provides new insights into oat lodging resistance, and the key genes and metabolites identified in this study provide direct targets for improving lodging resistance in oat breeding.