Seasonal and Diurnal Regulation of Flowering <i>via</i> an Epigenetic Mechanism in <i>Arabidopsis thaliana</i>

Abstract

Successful plant reproduction requires the precise control of the onset of flowering, which involves the transition from the vegetative growth phase to the reproductive growth phase. As a facultative long-day annual species, Arabidopsis thaliana flowers after an exposure to low temperatures under long-day conditions. This seasonal and diurnal control of flowering involves various epigenetic regulatory activities. We herein review the mechanism underlying the relevant epigenetic regulation, with a focus on the two key flowering regulatory genes, FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT). The expression of FLC, which encodes a flowering repressor, is controlled via a complex epigenetic mechanism involving histone modifications and long noncoding RNAs to establish the winter memory of plants annually exposed to winter conditions. In contrast, the expression of FT, which encodes a flowering activator, is temporally regulated through the diurnal binding of polycomb group proteins to the FT promoter to ensure day-length-dependent flowering. Thus, flowering is robustly and dynamically mediated via an epigenetic mechanism to ensure it occurs at the most appropriate time.

Flowering Times of Wild Arabidopsis Accessions From Across Norway Correlate With Expression Levels of FT, CO, and FLC Genes

“…However, as FT was only expressed at the lowest levels of FLC across all accessions, it is possible that FLC acts somewhat like a switch, strongly blocking FT expression until it declines below some threshold level. This concept is similar to how CO protein accumulates at dusk, presumably to some sufficient level, to promote looping of the FT chromatin between distal and proximal promoter regions that, then, diurnally disrupts H3K27me3 repressive marks along the FT locus (Adrian et al, 2010;Luo et al, 2018;Shibuta and Matsunaga, 2019). Perhaps, in a reverse manner, the presence of FLC protein at the first intron of FT (Helliwell et al, 2006) is sufficient to inhibit CO-mediated chromatin looping of FT until FLC protein falls below some critical value.…”

Worldwide Research Trends on Microalgae and Recent Work in Cytologia

“…Spermatophyta is prominent in Cytologia, as the subject of 70 to 83% of the papers in the last two years. The subject species are very diverse, and include more detailed studies of well-known model plants such as Arabidopsis thaliana (Hayashi et al 2018b, Shibuta and Matsunaga 2019, Shimahara et al 2019, Toyoda and Matsunaga 2019 and onion, Allium cepa (Barbhuiya et al 2018, Verma and Srivastava 2018, Basu et al 2019, Roy and Roy 2019, Tütüncü et al 2019. Species with regional characteristics have also been reported, as pointed out in a Cytologia Focus two years ago (Kawano 2018).…”