Enhancing Agrobacterium-Mediated Hairy-Root Transformation Efficiency in Peanut Through the Application of GRF, GIF and WOX Genes

Peanut (Arachis hypogaea L.) is a major oil and economic crop, yet genetic transformation remains inefficient and time-consuming, hindering functional genomics and molecular breeding. In this study, we found that the use of GRF, GIF and WOX genes improved the efficiency of Agrobacterium-mediated peanut hairy-root transformation. Here, we identified multiple peanut Growth-Regulating Factor (GRF) genes, GRF-Interacting Factor (GRF-GIF) fusion genes and WUSCHEL-related homeobox (WOX) genes, constructed high-expression vectors, and delivered them into A. rhizogenes to infect 3–5 cm peanut stem segments cut from 30-day-old seedlings. Statistical analysis of the data showed that, relative to the empty-vector control, expression of these developmental regulators markedly enhanced hairy-root growth: the number of roots per explant increased by 1.3–2.4-fold. Observations using reporter constructs showed that growth factors (besides 2S-PL-GUS and GRF-2A-T-GUS) improved the transformation efficiency of hairy roots, among which the highest transformation efficiency of GRF-2A (396)-GIF-GUS was 85.14 ± 2.94%. Collectively, these findings provide an efficient and rapid platform for the study of peanut gene function.