Analysis of the phytochrome gene family in Ceratodon purpureus by gene targeting reveals the primary phytochrome responsible for photo- and polarotropism
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Using gene targeting by homologous recombination in Ceratodon purpureus, we were able to knock out four phytochrome photoreceptor genes independently and to analyze their function with respect to red light dependent phototropism, polarotropism, and chlorophyll content. The strongest phenotype was found in knock-out lines of a newly described phytochrome gene termed CpPHY4 lacking photo- and polarotropic responses at moderate fluence rates. Eliminating the atypical phytochrome gene CpPHY1, which is the only known phytochrome-like gene containing a putative C-terminal tyrosine kinase-like domain, affects red light-induced chlorophyll accumulation. This result was surprising, since no light dependent function was ever allocated to this unusual gene.
KeywordsCeratodon Gene targeting Knock-out Phytochrome
Rapid amplification of cDNA ends
Reverse transcription based polymerase chain reaction
We would like to thank Dennis Hauser, Frankfurt a. M., Germany, for providing his software “MossBendingPlotter 3.0” visualizing the bending angles presented in Figs. 4, 5, 6, Tanja Gans for technical assistance and Man Mohan (Stowers Institute for medical research, Kansas City, MO, USA) for critical reading the manuscript and helpful discussion. The work was funded by grants of the Deutsche Forschungsgemeinschaft to CF (FO-290/4-1).
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