The expression of phototropins in Arabidopsis leaves: developmental and light regulation

Abstract

Phototropins are blue light receptors, which play different roles during plant development. Two phototropins of Arabidopsis thaliana, phot1 and phot2, have strongly overlapping functions. In seedlings, both photoreceptors are responsible for phototropism. In mature leaves they redundantly regulate leaf shape, stomatal opening, and the accumulation of chloroplasts, whereas phototropin2 alone controls chloroplast avoidance response. Light not only activates phototropins, but also affects the level of their expression. In Arabidopsis seedlings, PHOT1 is downregulated and PHOT2 is upregulated by light. Since data on transcription levels of phototropins in mature Arabidopsis leaves is scarce, a comprehensive real-time PCR study of PHOT1 and PHOT2 expression during development was performed, from seedlings to senescing leaves. So far, neither the phototropin expression nor its modulation by light have been investigated during senescence. The results show that the general regulation pattern remains conserved during Arabidopsis lifecycle, whereas the level of transcripts fluctuates over time, pointing to the significance of the light control for functioning of phototropins. The second part of the study determined the influence of photosynthesis-derived signals and photoreceptor-activated transduction pathways on phototropin mRNA levels. The effects of blue and red light were examined using Arabidopsis mutant lines deficient in photoreceptors. The results reveal a complex network of interactions between these receptors in the regulation of phototropin transcription profiles. Cryptochrome1 and phytochromeB appear to be main photoreceptors involved in the regulation of PHOT1 transcript accumulation. The expression of PHOT2 is dependent on both cryptochromes and phytochromeA.

Light signaling and plant responses to blue and UV radiations—Perspectives for applications in horticulture

“…et al, 2006;Inoue et al, 2008b), chloroplast accumulation and stomatal opening (Ma et al, 2001). However, phot2 is the only phot involved in the chloroplast avoidance response (Jarillo et al, 2001;Łabuz et al, 2012).…”

The impact of temperature on blue light induced chloroplast movements in Arabidopsis thaliana

“…RNA isolation and real-time PCR were performed as in [37]. Briefly, RNA was isolated with a Spectrum Plant Total Kit (Sigma-Aldrich) and reverse transcription was prepared with the RevertAid M-MuLV Reverse Transcriptase Kit (Thermo Scientific) using random hexamer primers.…”

“…Real-time PCR was performed with SYBR Green JumpStart Taq ReadyMix (Sigma-Aldrich) and a thermal cycler (Rotor-Gene 6000, Corbett Research, Australia). The primer sequences for PHOT1 and PHOT2 have been listed in [37]. The reference gene primers: UBC, SAND, PDF2, UBQ10 were based on [38].…”

Resonance energy transfer between FMN molecules in the presence of dimers: A review

“…1) play extremely important biological roles in redox reactions of the respiratory chain, Krebs cycle, pirogronian dehydrogenase system and other reactions. As chromophores in photoreceptors flavins also take part in a variety of photobiological processes, among others in photodynamic effect, phototropism, phototaxis and chloroplast translocations [1][2][3][4][5], modulation of the circadian clock and regulation of flowering [6][7][8][9][10][11][12][13]. The research on flavoprotein photoreceptors has been discussed in many reviews [1,2,6,8,[14][15][16].…”

“…As chromophores in photoreceptors flavins also take part in a variety of photobiological processes, among others in photodynamic effect, phototropism, phototaxis and chloroplast translocations [1][2][3][4][5], modulation of the circadian clock and regulation of flowering [6][7][8][9][10][11][12][13]. The research on flavoprotein photoreceptors has been discussed in many reviews [1,2,6,8,[14][15][16]. Rapid progress can be observed in the characterization of photoreceptors, their structure [6,[16][17][18][19][20][21] and photochemistry, as well as in their functioning.…”