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The promoter activities of sucrose phosphate synthase genes in rice, OsSPS1 and OsSPS11, are controlled by light and circadian clock, but not by sucrose.

Yonekura M, Aoki N, Hirose T, Onai K, Ishiura M, Okamura M, Ohsugi R, Ohto C - Front Plant Sci (2013)

Bottom Line: These results suggest that these OsSPS promoters may not be regulated by sucrose levels in the tissues.Under the light-dark cycle, both OsSPS1 and OsSPS11 promoter activities were low in the dark and increased rapidly after the beginning of the light period.These results indicate that these OsSPS promoters are controlled by both light illumination and circadian clock and that the regulatory mechanism of promoter activity differs between the two OsSPS genes.

View Article: PubMed Central - PubMed

Affiliation: Bio Research Laboratory, Toyota Motor Corporation Toyota, Aichi, Japan.

ABSTRACT
Although sucrose plays a role in sugar sensing and its signaling pathway, little is known about the regulatory mechanisms of the expressions of plant sucrose-related genes. Our previous study on the expression of the sucrose phosphate synthase gene family in rice (OsSPSs) suggested the involvement of sucrose sensing and/or circadian rhythm in the transcriptional regulation of OsSPS. To examine whether the promoters of OsSPSs can be controlled by sugars and circadian clock, we produced transgenic rice plants harboring a promoter-luciferase construct for OsSPS1 or OsSPS11 and analyzed the changes in the promoter activities by monitoring bioluminescence from intact transgenic plants in real-time. Transgenic plants fed sucrose, glucose, or mannitol under continuous light conditions showed no changes in bioluminescence intensity; meanwhile, the addition of sucrose increased the concentration of sucrose in the plants, and the mRNA levels of OsSPS remained constant. These results suggest that these OsSPS promoters may not be regulated by sucrose levels in the tissues. Next, we investigated the changes in the promoter activities under 12-h light/12-h dark cycles and continuous light conditions. Under the light-dark cycle, both OsSPS1 and OsSPS11 promoter activities were low in the dark and increased rapidly after the beginning of the light period. When the transgenic rice plants were moved to the continuous light condition, both P OsSPS1 ::LUC and P OsSPS11 ::LUC reporter plants exhibited circadian bioluminescence rhythms; bioluminescence peaked during the subjective day with a 27-h period: in the early morning as for OsSPS1 promoter and midday for OsSPS11 promoter. These results indicate that these OsSPS promoters are controlled by both light illumination and circadian clock and that the regulatory mechanism of promoter activity differs between the two OsSPS genes.

No MeSH data available.


Related in: MedlinePlus

Promoter activities of OsSPS1 and OsSPS11 with the addition of sugars in continuous light. Fifteen-day-old plants were exposed to sugars added to the medium 24 h after the onset of illumination. (A) Bioluminescence of POsSPS1::LUCreporter plants without resetting the circadian clock. Data points indicate the mean ±SD of four independent plants in each line. We obtained essentially the same results from three independent experiments. (B) Bioluminescence of POsSPS11::LUCreporter plants. Data points indicate the mean ±SD of five independent plants in each line. We obtained essentially the same results from three independent experiments. (C) Endogenous sugar contents of wild-type (non-transgenic) plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or no sugar (0%, water). The y-axis represents sugar contents (nmol) per fresh weights of the plants (mg). Error bars indicate the SD of three independent plants. We obtained essentially the same results from three independent experiments. (D) mRNA levels of OsSPS1 in non-transgenic plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or water. Values were normalized to the expression level of a rice polyubiquitin gene (RUBIQ1). Note that the data at time 0 indicate the relative expression levels before the supply of sugars. Error bars indicate the standard errors of three independent plants. We obtained essentially the same results from three independent experiments.
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Figure 1: Promoter activities of OsSPS1 and OsSPS11 with the addition of sugars in continuous light. Fifteen-day-old plants were exposed to sugars added to the medium 24 h after the onset of illumination. (A) Bioluminescence of POsSPS1::LUCreporter plants without resetting the circadian clock. Data points indicate the mean ±SD of four independent plants in each line. We obtained essentially the same results from three independent experiments. (B) Bioluminescence of POsSPS11::LUCreporter plants. Data points indicate the mean ±SD of five independent plants in each line. We obtained essentially the same results from three independent experiments. (C) Endogenous sugar contents of wild-type (non-transgenic) plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or no sugar (0%, water). The y-axis represents sugar contents (nmol) per fresh weights of the plants (mg). Error bars indicate the SD of three independent plants. We obtained essentially the same results from three independent experiments. (D) mRNA levels of OsSPS1 in non-transgenic plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or water. Values were normalized to the expression level of a rice polyubiquitin gene (RUBIQ1). Note that the data at time 0 indicate the relative expression levels before the supply of sugars. Error bars indicate the standard errors of three independent plants. We obtained essentially the same results from three independent experiments.

Mentions: To examine whether the promoter activities of OsSPS1 and OsSPS11 are regulated by sugars, we measured the bioluminescence of the POsSPS1::LUC and POsSPS11::LUC reporter plants after exogenously supplying 5% (w/v) sucrose, 5% (w/v) glucose, or 5% (w/v) mannitol. In both of the reporter plants, bioluminescence levels did not fluctuate significantly during the 48-h continuous light, even without the sugar treatments (0%). We did not observed significant changes in bioluminescence with any treatment (Figures 1A,B).


The promoter activities of sucrose phosphate synthase genes in rice, OsSPS1 and OsSPS11, are controlled by light and circadian clock, but not by sucrose.

Yonekura M, Aoki N, Hirose T, Onai K, Ishiura M, Okamura M, Ohsugi R, Ohto C - Front Plant Sci (2013)

Promoter activities of OsSPS1 and OsSPS11 with the addition of sugars in continuous light. Fifteen-day-old plants were exposed to sugars added to the medium 24 h after the onset of illumination. (A) Bioluminescence of POsSPS1::LUCreporter plants without resetting the circadian clock. Data points indicate the mean ±SD of four independent plants in each line. We obtained essentially the same results from three independent experiments. (B) Bioluminescence of POsSPS11::LUCreporter plants. Data points indicate the mean ±SD of five independent plants in each line. We obtained essentially the same results from three independent experiments. (C) Endogenous sugar contents of wild-type (non-transgenic) plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or no sugar (0%, water). The y-axis represents sugar contents (nmol) per fresh weights of the plants (mg). Error bars indicate the SD of three independent plants. We obtained essentially the same results from three independent experiments. (D) mRNA levels of OsSPS1 in non-transgenic plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or water. Values were normalized to the expression level of a rice polyubiquitin gene (RUBIQ1). Note that the data at time 0 indicate the relative expression levels before the supply of sugars. Error bars indicate the standard errors of three independent plants. We obtained essentially the same results from three independent experiments.
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Related In: Results  -  Collection

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Figure 1: Promoter activities of OsSPS1 and OsSPS11 with the addition of sugars in continuous light. Fifteen-day-old plants were exposed to sugars added to the medium 24 h after the onset of illumination. (A) Bioluminescence of POsSPS1::LUCreporter plants without resetting the circadian clock. Data points indicate the mean ±SD of four independent plants in each line. We obtained essentially the same results from three independent experiments. (B) Bioluminescence of POsSPS11::LUCreporter plants. Data points indicate the mean ±SD of five independent plants in each line. We obtained essentially the same results from three independent experiments. (C) Endogenous sugar contents of wild-type (non-transgenic) plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or no sugar (0%, water). The y-axis represents sugar contents (nmol) per fresh weights of the plants (mg). Error bars indicate the SD of three independent plants. We obtained essentially the same results from three independent experiments. (D) mRNA levels of OsSPS1 in non-transgenic plants after an exogenous supply of 5% sucrose, 5% glucose, 5% mannitol, or water. Values were normalized to the expression level of a rice polyubiquitin gene (RUBIQ1). Note that the data at time 0 indicate the relative expression levels before the supply of sugars. Error bars indicate the standard errors of three independent plants. We obtained essentially the same results from three independent experiments.
Mentions: To examine whether the promoter activities of OsSPS1 and OsSPS11 are regulated by sugars, we measured the bioluminescence of the POsSPS1::LUC and POsSPS11::LUC reporter plants after exogenously supplying 5% (w/v) sucrose, 5% (w/v) glucose, or 5% (w/v) mannitol. In both of the reporter plants, bioluminescence levels did not fluctuate significantly during the 48-h continuous light, even without the sugar treatments (0%). We did not observed significant changes in bioluminescence with any treatment (Figures 1A,B).

Bottom Line: These results suggest that these OsSPS promoters may not be regulated by sucrose levels in the tissues.Under the light-dark cycle, both OsSPS1 and OsSPS11 promoter activities were low in the dark and increased rapidly after the beginning of the light period.These results indicate that these OsSPS promoters are controlled by both light illumination and circadian clock and that the regulatory mechanism of promoter activity differs between the two OsSPS genes.

View Article: PubMed Central - PubMed

Affiliation: Bio Research Laboratory, Toyota Motor Corporation Toyota, Aichi, Japan.

ABSTRACT
Although sucrose plays a role in sugar sensing and its signaling pathway, little is known about the regulatory mechanisms of the expressions of plant sucrose-related genes. Our previous study on the expression of the sucrose phosphate synthase gene family in rice (OsSPSs) suggested the involvement of sucrose sensing and/or circadian rhythm in the transcriptional regulation of OsSPS. To examine whether the promoters of OsSPSs can be controlled by sugars and circadian clock, we produced transgenic rice plants harboring a promoter-luciferase construct for OsSPS1 or OsSPS11 and analyzed the changes in the promoter activities by monitoring bioluminescence from intact transgenic plants in real-time. Transgenic plants fed sucrose, glucose, or mannitol under continuous light conditions showed no changes in bioluminescence intensity; meanwhile, the addition of sucrose increased the concentration of sucrose in the plants, and the mRNA levels of OsSPS remained constant. These results suggest that these OsSPS promoters may not be regulated by sucrose levels in the tissues. Next, we investigated the changes in the promoter activities under 12-h light/12-h dark cycles and continuous light conditions. Under the light-dark cycle, both OsSPS1 and OsSPS11 promoter activities were low in the dark and increased rapidly after the beginning of the light period. When the transgenic rice plants were moved to the continuous light condition, both P OsSPS1 ::LUC and P OsSPS11 ::LUC reporter plants exhibited circadian bioluminescence rhythms; bioluminescence peaked during the subjective day with a 27-h period: in the early morning as for OsSPS1 promoter and midday for OsSPS11 promoter. These results indicate that these OsSPS promoters are controlled by both light illumination and circadian clock and that the regulatory mechanism of promoter activity differs between the two OsSPS genes.

No MeSH data available.


Related in: MedlinePlus