The basic methods used in current practice for stable and transient expression of heterologous genes in plants are presented and compared. The key areas of research in the heterologous expression of genes in plants have been identified by analyzing literature and experimental data: modeling of metabolic pathways; creation of marker-free transgenic plants; the search for new regulatory elements and plant genes influencing the efficiency of expression of heterologous genes in plants; development of new methods for analyzing of transgenic plants and new approaches to the expression of heterologous genes in plants.