Molecular Insights into Microspore Embryogenesis: Transcriptomic Dynamics in Barley and Wheat

The development of efficient protocols for doubled haploid (DH) production in cereals has long been a major focus of plant biotechnology research. Most efforts have concentrated on in vitro microspore embryogenesis (ME) systems, which provide a powerful route for the rapid generation of homozygous lines. To optimize these systems, numerous empirical, trial-and-error approaches have been employed to evaluate the effects of genotype, stress treatments, culture media composition, and mother-plant growth and culture conditions on the efficiency of DH production. These strategies have been essential, given the limited understanding of the cellular and molecular mechanisms underlying ME. However, recent advances in high-throughput transcriptomic technologies, particularly RNA sequencing (RNA-seq), have substantially expanded our insight into the regulatory networks involved in cellular reprogramming and developmental transitions during ME. This review summarizes the most recent findings on the transcriptional dynamics of ME in barley and wheat, aiming to provide comprehensive insights into the molecular mechanisms involved, thereby facilitating the development of more effective strategies for DH production.