Comparative transcriptome profiling and functional analysis of GmRAMOSA1 as a key regulator of adventitious shoot regeneration in soybean.

Abstract

Key message: This study identifies GmRAMOSA1 as a key regulator of adventitious shoot regeneration in soybean and uncovers its regulatory network via comparative transcriptome profiling, providing new insights into the molecular mechanism of soybean shoot organogenesis. Soybean genetic transformation is strongly constrained by genotype-dependent in vitro regeneration capacity, particularly in adventitious shoot formation. Here, we compared the highly regenerable cultivar Dongnong 50 (DN50) with the low regenerative capacity Sichuan landrace Gongqiudou 5 (GQD5) using a cotyledonary node-based adventitious shoot induction system. RNA sequencing (RNA-seq) was performed at multiple stages post-induction. Hormone-related pathways were significantly enriched, and genes involved in auxin and cytokinin signaling exhibited distinct temporal dynamics between DN50 and GQD5. Integration of co-expression network analysis and promoter motif enrichment prioritized GmRAMOSA1 (GmRA1) as a candidate regulator. Overexpression of GmRA1 in the GQD5 background significantly increased adventitious shoot regeneration and was associated with elevated expression of several meristem-identity and hormone-responsive genes. This study highlights a promising molecular target for enhancing soybean regeneration and transformation efficiency.