A Histone Demethylase GbJMJ25 Regulates Somatic Embryogenesis Cotton by Modulating ROS

Abstract Somatic embryogenesis in Gossypium barbadense is highly genotype-dependent, which constrains its application in cotton molecular breeding. The formation of primary embryogenic cells from black-brown non-embryogenic callus represents a critical step in this process. Among the genes significantly differentially expressed during this transition, we identified a histone demethylase gene, GbJMJ25 . In this study, we demonstrate that the emergence of primary embryogenic cells is accompanied by pronounced changes in cellular redox status, concurrent with the down-regulation of GbJMJ25 expression. Quantitative PCR analysis indicated that GbJMJ25 expression is modulated by abiotic stress factors such as ABA and PEG. Silencing GbJMJ25 enhanced peroxidase accumulation and maintained lower intracellular ROS levels in cotton plants under abiotic stress. In non-embryogenic callus of G . barbadense , knockdown of GbJMJ25 promoted the accumulation of anthocyanins, SOD, and CAT, thereby facilitating the conversion to embryogenic cells. Nevertheless, this transition remained dependent on auxin supplementation, suggesting that auxin induces substantial intracellular changes—including rendering cells into a “stressed” state—during the shift from non-embryogenic to embryogenic cells. By regulating cellular ROS homeostasis, GbJMJ25 appears to influence cell survival and subsequent differentiation. In summary, our findings indicate that modulation of GbJMJ25 expression can enhance plant regeneration through the somatic embryogenesis system, offering a candidate gene for improving genetic transformation techniques mediated by somatic embryogenesis in G . barbadense .