UV-B effects in plant development

PAULA CASATI

Congreso; XL Reunión Anual de la Sociedad de Bioquímica y Biología Molecular de Chile; 2017

Plants are exposed to a broad spectrum of environmental stimuli throughout their life time, being sunlight the main source of energy and information. UV-B is a component of the solar radiation that induces a number of modifications in plant growth and development. UV-B radiation inhibits A. thaliana (a dicot plant) growth by inhibiting cell division in proliferating leaves. UV-B also affects maize (a monocot) growth. Our results demonstrate that the decrease in leaf growth in UV-B irradiated leaves is a consequence of a reduction in cell production, and a shortened growth zone (GZ). To determine the molecular pathways involved in UV-B inhibition of leaf growth, we performed RNA sequencing on isolated GZ tissues of control and UV-B exposed plants. Our results show a link between the observed leaf growth inhibition and the expression of specific cell cycle and developmental genes, including Growth Regulating Factors (GRFs) and transcripts for proteins participating in different hormone pathways. On the other hand, UV-B also induces changes in flowering time. We demonstrated that Arabidopsis plants grown under white light supplemented with UV-B show a delay in flowering time. Using a combination of gene expression analysis and UV-B irradiation of different flowering mutants, we gained insight into the pathways involved in the observed flowering time delay in UV-B exposed Arabidopsis plants. Modification in the expression of several flowering time genes was determined. UV-B exposure of flowering mutants supports the involvement of the PRC2 complex in the observed delay in flowering time, mostly through the age pathway.