UV-B radiation delays flowering time through changes in the PRC2 complex activity and miR156 levels in Arabidopsis thaliana

MARCELA DOTTO; MARÍA SOL GOMEZ; MARÍA SOLEDAD SOTO; PAULA CASATI

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 41 p. 1394 - 1406

0140-7791

UV‐B is a high‐energy component of the solar radiation perceived by the plant and induces anumber of modifications in plant growth and development, including changes in flowering time.However, the molecular mechanisms underlying these changes are largely unknown. In the presentwork, we demonstrate that Arabidopsis plants grown under white light supplemented withUV‐B show a delay in flowering time, and this developmental reprogramming is mediated bythe UVR8 photoreceptor. Using a combination of gene expression analyses and UV‐B irradiationof different flowering mutants, we gained insight into the pathways involved in the observedflowering time delay in UV‐B‐exposed Arabidopsis plants. We provide evidence that UV‐B lightdownregulates the expression of MSI1 and CLF, two of the components of the polycomb repressivecomplex 2, which in consequence drives a decrease in H3K27me3 histone methylation ofMIR156 and FLC genes. Modification in the expression of several flowering time genes as a consequenceof the decrease in the polycomb repressive complex 2 activity was also determined.UV‐B exposure of flowering mutants supports the involvement of this complex in the observeddelay in flowering time, mostly through the age pathway.