Transition from seed to seedling is one of the critical developmental steps, dramatically affecting plant growth and viability. Before plants enter the vegetative phase of their ontogenesis, massive rearrangements of signaling pathways and switching of gene expression programs are required. This results in suppression of the genes controlling seed maturation and activation of those involved in regulation of vegetative growth. At the level of hormonal regulation, these events are controlled by the balance of abscisic acid and gibberellins, although ethylene, auxins, brassinosteroids, cytokinins, and jasmonates are also involved. The key players include the members of the LAFL network—the transcription factors LEAFY COTYLEDON1 and 2 (LEC 1 and 2), ABSCISIC ACID INSENSITIVE3 (ABI3), and FUSCA3 (FUS3), as well as DELAY OF GERMINATION1 (DOG1). They are the negative regulators of seed germination and need to be suppressed before seedling development can be initiated. This repressive signal is mediated by chromatin remodeling complexes—POLYCOMB REPRESSIVE COMPLEX 1 and 2 (PRC1 and PRC2), as well as PICKLE (PKL) and PICKLE-RELATED2 (PKR2) proteins. Finally, epigenetic methylation of cytosine residues in DNA, histone post-translational modifications, and post-transcriptional downregulation of seed maturation genes with miRNA are discussed. Here, we summarize recent updates in the study of hormonal and epigenetic switches involved in regulation of the transition from seed germination to the post-germination stage.

This review is devoted to the analysis of molecular genetic mechanisms of controlling the type of growth habit of grain legumes (pea, soybean, common bean, vigna); it provides information about known homologous genes TFL1, LFY, AP1, FUL, FT, and FD. Significant changes in plant architecture were during domestication of grain legumes. Many wild relatives of legumes are characterized by an indeterminate growth habit type, cultivated plants are characterized by indeterminate and determinate types. In plants with a determinate growth habit type, terminal inflorescence is formed at transition from the vegetative phase to the reproductive phase. These plants are characterized by a complex of features: simultaneous maturation of beans, resistance to lodging, etc. In indeterminate type of growth habit, the apical shoot meristem remains active during plant life. The main genes responsible for the plant transition to flowering are the homologs of the Arabidopsis genes LFY, TFL1, AP1. TFL1 gene is responsible for maintenance of growth of the shoot apical meristem; its homologs were identified in pea (PsTFL1a), soybean (Dt1/GmTFL1), common bean (PvTFL1y), cowpea (VuTFL1). The identification and characterization of the genes responsible for the type of stem growth habit are necessary for the successful selection of modern varieties suitable for mechanized cultivation. Design of molecular markers that diagnose this important breeding trait at early plant development stages, will help to determine the type of stem growth habit.