The transition from vegetative to reproductive growth is a major developmental switch in the life cycle of plants. During the vegetative phase the plant produces leaves, while during the reproductive phase flowers are produced. A typical flower contains four types of floral organ (sepals, petals, stamens and carpels). To generate the different floral organs a dynamic regulation of gene expression is needed, which is achieved by the action of master transcription factors. However, how these master regulators regulate gene expression in the flower is still poorly understood.
In this study A. Pajoro focussed on two transcription factors (SEP3 and AP1), which are essential for the formation of the floral organs in the model species Arabidopsis. She identified and characterized genes that are controlled by these two transcription factors at different stages of Arabidopsis flower development. She obtained a comprehensive overview of active genes during floral organ development. Furthermore, she studied the relationship between DNA packaging and gene expression. She discovered that the two transcription factors bind DNA followed by an increase in DNA accessibility, suggesting that the two transcription factors may act as pioneer factors. This novel finding was published in Genome Biology.