Targeting E(z) methyltransferase inhibitor GSK126 promotes adventitious root induction in Larix kaempferi

Efficient asexual reproduction techniques are crucial for the expansion of larch; however, the process of adventitious roots (ARs) regeneration has hindered its development. Through comprehensive root development proteomics and transcriptomics analysis, we have identified key epigenetic modifying enzymes involved in the organogenesis of Larix kaempferi. Subsequently, we cloned the enhancer of zeste homolog CURLY LEAF (CLF) from L. kaempferi and performed molecular modeling. The molecular docking results between LkCLF and the histone H3 lysine 27 trimethylation (H3K27me3) inhibitor GSK126 revealed the affinity value is –9 kcal/mol, indicating strong binding interaction between the two. Adding inhibitor GSK126 to the ARs induction medium, morphologically clear primordia appeared between 20 and 25 days after cutting, which was 7–10 d earlier than in the control group, accompanied by an 18.17% increase in rooting rate. Besides, western blot analysis demonstrated the effective inhibition of H3K27me3 levels in stem bases treated with GSK126. Real-time quantitative reverse transcription polymerase chain reaction results showed a significantly elevated expression of BABY BOOM2 compared with 0 μM GSK126 or dimethyl sulfoxide treated groups. Our findings suggest that treating stem bases with 0.01 μM GSK126 during early-stage AR regeneration expedites the developmental process and enhances the rooting rate. This study lays the foundation for a deeper understanding of the roles by H3K27me3 and polycomb repressive complex 2 in the AR regeneration of larch cuttings.