UV-B radiation inhibits cell proliferation in maize leaves through transcriptional changes of cell cycle and developmental genes

JULIETA FINA; ROMINA CASADEVALL; GERRIT BEEMSTER; PAULA CASATI

Congreso; 11th International Plant Molecular Biology Congress; 2015

Growth inhibition is one of the most consistent plant responses to UV-B exposure; and this radiation, both as part of the solar spectrum in the field and from UV-B lamps in controlled environments, affects leaf growth in a wide range of species. Recently, we have demonstrated that the exposure of Arabidopsis developing leaves to UV-B doses that cause DNA damage inhibits leaf expansion as a consequence of an early end of the proliferative phase of leaf development. In addition, we also reported that the exposure of maize plants to elevated UV-B doses causes an inhibition of leaf growth, but the mechanism by which this response occurs was completely unknown. In this work, we analyzed the response of maize leaves to solar UV-B doses. We found that solar UV-B in summer at Rosario, Argentina (32º latitude), inhibits leaf growth without causing any other visible stress symptoms. This treatment produced a 35% reduction in leaf length compared to that from plants grown in control conditions in the absence of UV-B, and grew 30% slower. We conducted kinematic analyses of cell division and expansion to understand the impact of UV-B on these cellular processes and we utilized RNAseq using Illumina-technology to characterize the transcriptome of the leaf growing zone of control and UV-B exposed plants with the aim of shedding light on the molecular pathways involved in UV-B inhibition of leaf growth. Our results show a link between the observed leaf growth inhibition and the expression of specific cell cycle and developmental genes.