Somatic embryogenesis (SE) is a key step in plant regeneration and propagation, but the mechanisms underlying SE in oil palm still stay unclear. Integrated analysis of metabolome and transcriptome data showed that 13 metabolites are specifically accumulated in somatic embryo, of which caffeate was 16.6-fold (p = 0.0002) higher than in callus. Moreover, caffeate was significantly correlated with phytohormone signaling genes including ethylene receptor (ETR2-2), auxin efflux carrier component 3a (PIN3A), auxin response factor (ARF15-2), and several SE transcription factors (TFs) including WUSCHEL-related homeobox (WOX), VIVIPAROUS1(VP1), BABY BOOM2 (BBM2). Furthermore, staining and microscopic observation showed that phenolic acids highly accumulated in the center of newly formed callus clusters and lignin is predominant in somatic embryo than in callus, indicated that caffeate (the major phenolic acids in glycosylated form and the precursor of lignin biosynthesis) may play an important role in SE. Our results provide a better understanding of the SE mechanism in oil palm.

体细胞胚胎发生 (SE) 是植物再生和繁殖的关键步骤，但油棕中 SE 的机制仍不清楚。代谢组和转录组数据的综合分析表明，13 种代谢物在体细胞胚胎中特异性积累，其中咖啡酸为 16.6 倍（p = 0.0002) 高于愈伤组织。此外，咖啡酸与植物激素信号基因显着相关，包括乙烯受体 (ETR2-2)、生长素外排载体成分 3a (PIN3A)、生长素反应因子 (ARF15-2) 和几种 SE 转录因子 (TF)，包括 WUSCHEL 相关同源框(WOX)、VIVIPAROUS1(VP1)、婴儿潮2 (BBM2)。此外，染色和显微镜观察表明，酚酸在新形成的愈伤组织簇的中心高度积累，并且木质素在体细胞胚中比在愈伤组织中占主导地位，表明咖啡酸（糖基化形式的主要酚酸和木质素生物合成的前体）可能在 SE 中扮演重要角色。我们的结果提供了对油棕中 SE 机制的更好理解。