Effects of Epigenetic Inhibitors on Somatic Embryogenesis in Wheat (Triticum aestivum L.)

Abstract

Wheat (Triticum aestivum L.) is a global staple cereal known for its nutritional value and economic significance. Somatic embryogenesis (SE) is a powerful biotechnological tool for plant genetic improvement, driven by intricate epigenetic mechanisms as well as controlled by key genes such as Wuschel-related HOMEOBOX (WOX4), Leafy cotyledon (LEC1), Baby Boom 1 (BBM1), and Somatic embryogenesis receptor kinase (TaSERK). This study investigates the impact of different concentrations (0.1, 0.5, 1, and 2 µM) of Trichostatin A (TSA) and 5-Azacytidine (5-Azac), recognized epigenetic inhibitors, on mature embryos of Kırık bread wheat variety cultured in a callus formation medium. In vitro parameters including Callus formation frequency (CFF) (mg), callus fresh weight (CFW) (%), embryogenic callus formation frequency (ECFF) (%), embryogenic callus frequency (RECF) (%), and regeneration efficiency (RE) (number) as well as expression levels of WOX4, LEC1, BBM1, and TaSERK genes, were evaluated at 14, 28, and 42 days after initiation of tissue culture (DAI). The results show that TSA and 5-Azac treatments had a considerable influence on the in vitro parameters tested. Furthermore, these compounds had a significant effect on the mRNA expression levels of the WOX4, LEC1, BBM1, and TaSERK genes, which are important in SE. Specifically, LEC1 expression peaked at 42 DAI across all treatments, while WOX4 and BBM1 peaked at 14 DAI. TaSERK expression decreased by 42 DAI, with variations depending on treatment at previous time points. As a result of this study, 0.5 µM TSA and 5 µM 5-Azac treatments resulted in optimal plant regeneration, emphasizing the importance of epigenetic regulators in promoting somatic embryogenesis via endosperm-supported mature embryo in wheat. This study suggests addressing epigenetic systems to improve SE protocols and inform wheat genetic engineering and breeding initiatives for sustainable agriculture and food security.