A Histological-Based Study of the Effect of Different Substrate Temperatures on Adventitious Root Formation in Peach Hardwood Cuttings

The propagation of peach rootstocks, particularly adventitious root (AR) formation, is influenced by multiple factors, with substrate temperature being crucial. This experiment studied the differential gene expression patterns of GF677 rootstock cuttings treated with 200 mg/L IBA under various substrate temperatures (unheated, 19℃, 22℃, 25℃, and 28℃) and cutting periods (7, 14, and 21 days). The results showed a maximum rooting rate of 91% at 25℃ for 40 days, with the highest number of differentially expressed genes (DEGs) observed between 22-25℃. Therefore, the optimal temperature for propagation was determined to be 25℃. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses highlighted “starch and sucrose metabolism” and “plant hormone signal transduction” as enriched pathways. Specifically, 26 plant hormone signaling pathways (ARFs, LBDs, SAURs, and GH3) and 22 AR formation-related pathways (AUR3, LRP1, RGF1, AIR9, AP2, and NAC) were identified from these DEGs. Weighted gene co-expression network analysis (WGCNA) clarified the involvement of various transcription factors (WRKYs, ERFs, NACs, bHLHs, bZIPs, and MYBs) in AR formation. These findings indicate significant differences in gene expression under different combinations of substrate temperatures and cutting periods. Overall, this study enhances our understanding of the molecular mechanisms underlying peach tree asexual reproduction.