体细胞胚发生是克隆繁殖和植物转化的有力工具，涉及分化的体细胞的细胞重编程以获得多能性。可以通过用植物生长调节剂处理外植体来诱导体细胞胚发生。但是，包括植物学上重要的谷类作物在内的几种植物种类，除胚芽组织外，对去分化和转化均保持顽固性。
体细胞胚发生也可以通过选择性胚胎因子的异位表达来诱导，包括在谷物中通过BABY BOOM（BBM）转录因子表达。 BBM基因如何绕过对外源激素的需求尚不清楚。
在这里，我们调查了OsBBM1（（Oryza sativa BABY BOOM1））诱导水稻体细胞胚发生过程中的下游目标。OsBBM1的瞬时诱导导致植物生长素生物合成OsYUCCA基因的上调。OsBBM1的持续诱导导致体细胞胚发生而无需外源性对OsBBM1下游靶标OsYUCCA6，OsYUCCA7和OsYUCCA9的遗传突变分析表明，它们是正常水稻发育（包括根和茎发育）所必需的，尽管存在外源性生长素，OsYUCCA三重突变体的体细胞胚发生能力也受到很大损害。我们发现外源生长素诱导水稻体细胞胚发生需要功能性BBM基因，
因此，OsBBM1介导的细胞重编程和体胚发生可能通过直接上调OsYUCCA基因来增加局部生长素，这项研究揭示了如何在分化中建立体胚发生的机制细节水稻中的组织，单子叶植物模型和具有重要农艺意义的谷物作物，未来可能会改善植物的组织培养再生能力。
Somatic embryogenesis, a powerful tool for clonal propagation and for plant transformation, involves cellular reprogramming of differentiated somatic cells to acquire pluripotency. Somatic embryogenesis can be induced by treating explants with plant growth regulators. However, several plant species including agronomically important cereal crops remain recalcitrant to dedifferentiation and transformation except from embryonic tissues. Somatic embryogenesis can also be induced by ectopic expression of select embryonic factors, including in cereals by BABY BOOM (BBM) transcription factors. How BBM genes bypass the need for exogenous hormones is not well understood. Here, we investigated downstream targets during induction of somatic embryogenesis in rice by OsBBM1 ((Oryza sativa BABY BOOM1). Transient induction of OsBBM1 led to the upregulation of auxin biosynthesis OsYUCCA genes. Continued induction of OsBBM1 resulted in somatic embryogenesis without the need for exogenous auxins. Genetic mutant analysis of OsBBM1 downstream targets, OsYUCCA6, OsYUCCA7 and OsYUCCA9, show that they are required for normal rice development including root and shoot development. Somatic embryogenic potential of OsYUCCA triple mutants was highly compromised despite the presence of exogenous auxin. Additionally, we show that somatic embryogenesis induction by exogenous auxin in rice requires functional BBM genes. Thus, OsBBM1 mediated cellular reprogramming and somatic embryogenesis likely involves increased localized auxin through direct upregulation of OsYUCCA genes. This study reveals mechanistic details of how somatic embryogenesis is established in differentiated tissues in rice, a monocot model and agronomically important cereal crop, with the potential utility to improve regeneration from tissue culture for recalcitrant plants in future.
