Flowering rooted in gene regulatory

The researchers determined that gene regulatory mechanisms at an early embryonic stage govern the flowering behavior of Arabidopsis later in development. The paper is published in the journal PNAS.Gregor Mendel Institute of Molecular group leader and co-corresponding author Michael Nodine said that this research answers many questions like how early events shape the ability of organisms. The research demonstrates that gene regulatory mechanisms established in early embryos forecast events that have major physiological consequences long after they are initiated.

Developmental phase transitions are controlled by precise quantitative regulation of gene expression. Decades of research on the Arabidopsis floral repressor Flowering Locus C , which is produced by default in a plant embryo following fertilization, has revealed the involvement of multiple molecular pathways that regulate its expression levels.

The pathways converge to set Flowering Locus C expression levels such that flowering only occurs in response to favorable environmental cues. In other words, the regulation mechanisms ensure that plants overwinter before flowering, a process called vernalization, as opposed to flowering multiple times a year. The molecular interactions regulating Flowering Locus C expression at specific developmental stages have remained poorly understood.

The researchers show that the Flowering Locus C transcript is antagonistically regulated in a co-transcriptional manner and that these effects take place within an early developmental stage in the plant embryo. The researchers also found that FCA promotes the attachment of a poly-A tail near the transcription start site of the FLC mRNA, which produces the shorter and non-functional FLC protein. FRI promotes the attachment of the poly-A tail further downstream in the FLC mRNA, thus resulting in the longer and functional version of FLC.