Summary

Evolutionary patterns in plant transcriptional response to UV-B radiation

Laura Monforte visited Dr. Ales Pecinka in Cologne (31 days in November/December 2013)

I have spent one month in the laboratory of Genome and Epigenome Evolution (Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research) in Cologne (Germany), under the supervision of Dr. Ales Pecinka (group leader).

Our main objective was to study the evolutionary patterns in plant transcriptional response to UV-B radiation after the conquest of land by photosynthetic organisms, as an adaptation to enhanced sun conditions. We used (initially) four species belonging to different evolutionary lineages:

- Green unicellular alga: Chlamydomonas reinhardtii.

- Bryophytes: Physcomitrella patens and Marchantia polymorpha.

- Flowering plant: Arabidopsis thaliana.

Samples of these species were cultivated in vitro in a growth chamber for two-three weeks and then irradiated using UV lamps (Philips TL12/40W). Using cut-off filters, we imposed four different culture conditions (including a UV-B-free control and a true control with no UV radiation) to study the influence of both short and long UV-B radiation.

RNA of irradiated samples was isolated and its concentration and quality were measured. All RNA samples with the integrity number (RIN) higher than 8.0 were used to prepare RNA-sequencing libraries, and then cDNA quality was tested in the Genome Center and the libraries were sequenced.

The project is still ongoing and will be continued by a guest scientist. Thus, definitive results have not yet been obtained. Nevertheless, we already know that all RNA of the four species and treatments were of high quality, with the RIN values higher than 8. In addition, some samples of A. thaliana and M. polymorpha have already been processed for next-generation sequencing at the Institute’s Genome Center.