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An engineered lipid remodeling system using a galactolipid synthase promoter during phosphate starvation enhances oil accumulation in plants.

Shimojima M, Madoka Y, Fujiwara R, Murakawa M, Yoshitake Y, Ikeda K, Koizumi R, Endo K, Ozaki K, Ohta H - Front Plant Sci (2015)

Bottom Line: Thus, the produced galactolipids are transferred to extraplastidial membranes to substitute for phospholipids.Moreover, the Arabidopsis starchless phosphoglucomutase mutant, pgm-1, accumulated higher TAG levels than did wild-type plants under Pi-depleted conditions.We generated transgenic plants that expressed a key gene involved in TAG synthesis using the Pi deficiency-responsive MGD3 promoter in wild-type and pgm-1 backgrounds.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan.

ABSTRACT
Inorganic phosphate (Pi) depletion is a serious problem for plant growth. Membrane lipid remodeling is a defense mechanism that plants use to survive Pi-depleted conditions. During Pi starvation, phospholipids are degraded to supply Pi for other essential biological processes, whereas galactolipid synthesis in plastids is up-regulated via the transcriptional activation of monogalactosyldiacylglycerol synthase 3 (MGD3). Thus, the produced galactolipids are transferred to extraplastidial membranes to substitute for phospholipids. We found that, Pi starvation induced oil accumulation in the vegetative tissues of various seed plants without activating the transcription of enzymes involved in the later steps of triacylglycerol (TAG) biosynthesis. Moreover, the Arabidopsis starchless phosphoglucomutase mutant, pgm-1, accumulated higher TAG levels than did wild-type plants under Pi-depleted conditions. We generated transgenic plants that expressed a key gene involved in TAG synthesis using the Pi deficiency-responsive MGD3 promoter in wild-type and pgm-1 backgrounds. During Pi starvation, the transgenic plants accumulated higher TAG amounts compared with the non-transgenic plants, suggesting that the Pi deficiency-responsive promoter of galactolipid synthase in plastids may be useful for producing transgenic plants that accumulate more oil under Pi-depleted conditions.

No MeSH data available.


Related in: MedlinePlus

TAG accumulation in WT plants under Pi-depleted growth conditions. (A,B) WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and 0 mM (–Pi) or 1.0 mM (+Pi) Pi and were grown for 10 d. (A) TAG content in shoots and roots of WT Arabidopsis plants. FW, fresh weight. (B) Electron microscopy of WT Arabidopsis leaves. White arrows, oil droplets; C, chloroplast; M, mitochondrion; S, starch. Bar = 0.5 μm. (C) Effect of Pi concentration on shoot TAG levels in WT Arabidopsis plants. WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and various concentrations of Pi and were grown for 10 d. DW, dry weight. (D) TAG levels in shoots of tomato (Solanum lycopersicum L.) plants grown for 8 d with 1 mM Pi followed by 28 d with (+) or without (–) Pi. (E) Tobacco (Nicotiana tabacum) plants grown for 10 d with Pi followed by 21 d with (+) or without (–) Pi. (F) Barnyard grass (Echinochloa crus-galli) plants grown for 8 d with Pi followed by 28 d with (+) or without (–) Pi. Data are the mean ± SD from three independent experiments.
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Figure 2: TAG accumulation in WT plants under Pi-depleted growth conditions. (A,B) WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and 0 mM (–Pi) or 1.0 mM (+Pi) Pi and were grown for 10 d. (A) TAG content in shoots and roots of WT Arabidopsis plants. FW, fresh weight. (B) Electron microscopy of WT Arabidopsis leaves. White arrows, oil droplets; C, chloroplast; M, mitochondrion; S, starch. Bar = 0.5 μm. (C) Effect of Pi concentration on shoot TAG levels in WT Arabidopsis plants. WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and various concentrations of Pi and were grown for 10 d. DW, dry weight. (D) TAG levels in shoots of tomato (Solanum lycopersicum L.) plants grown for 8 d with 1 mM Pi followed by 28 d with (+) or without (–) Pi. (E) Tobacco (Nicotiana tabacum) plants grown for 10 d with Pi followed by 21 d with (+) or without (–) Pi. (F) Barnyard grass (Echinochloa crus-galli) plants grown for 8 d with Pi followed by 28 d with (+) or without (–) Pi. Data are the mean ± SD from three independent experiments.

Mentions: We also measured TAG levels in the roots of WT Arabidopsis plants grown under Pi-sufficient and Pi-depleted conditions. TAG levels in WT plants grown under Pi-depleted conditions were 5- to 6-fold higher in shoots and 1.5- to 2-fold higher in roots compared with those of plants grown under Pi-sufficient conditions (Figure 2A). It should be noted that we have also presented additional data here for shoot TAG levels for comparison with root TAG levels.


An engineered lipid remodeling system using a galactolipid synthase promoter during phosphate starvation enhances oil accumulation in plants.

Shimojima M, Madoka Y, Fujiwara R, Murakawa M, Yoshitake Y, Ikeda K, Koizumi R, Endo K, Ozaki K, Ohta H - Front Plant Sci (2015)

TAG accumulation in WT plants under Pi-depleted growth conditions. (A,B) WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and 0 mM (–Pi) or 1.0 mM (+Pi) Pi and were grown for 10 d. (A) TAG content in shoots and roots of WT Arabidopsis plants. FW, fresh weight. (B) Electron microscopy of WT Arabidopsis leaves. White arrows, oil droplets; C, chloroplast; M, mitochondrion; S, starch. Bar = 0.5 μm. (C) Effect of Pi concentration on shoot TAG levels in WT Arabidopsis plants. WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and various concentrations of Pi and were grown for 10 d. DW, dry weight. (D) TAG levels in shoots of tomato (Solanum lycopersicum L.) plants grown for 8 d with 1 mM Pi followed by 28 d with (+) or without (–) Pi. (E) Tobacco (Nicotiana tabacum) plants grown for 10 d with Pi followed by 21 d with (+) or without (–) Pi. (F) Barnyard grass (Echinochloa crus-galli) plants grown for 8 d with Pi followed by 28 d with (+) or without (–) Pi. Data are the mean ± SD from three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553410&req=5

Figure 2: TAG accumulation in WT plants under Pi-depleted growth conditions. (A,B) WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and 0 mM (–Pi) or 1.0 mM (+Pi) Pi and were grown for 10 d. (A) TAG content in shoots and roots of WT Arabidopsis plants. FW, fresh weight. (B) Electron microscopy of WT Arabidopsis leaves. White arrows, oil droplets; C, chloroplast; M, mitochondrion; S, starch. Bar = 0.5 μm. (C) Effect of Pi concentration on shoot TAG levels in WT Arabidopsis plants. WT Arabidopsis seedlings (10 d old) were transferred to MS agar containing 1% (w/v) sucrose and various concentrations of Pi and were grown for 10 d. DW, dry weight. (D) TAG levels in shoots of tomato (Solanum lycopersicum L.) plants grown for 8 d with 1 mM Pi followed by 28 d with (+) or without (–) Pi. (E) Tobacco (Nicotiana tabacum) plants grown for 10 d with Pi followed by 21 d with (+) or without (–) Pi. (F) Barnyard grass (Echinochloa crus-galli) plants grown for 8 d with Pi followed by 28 d with (+) or without (–) Pi. Data are the mean ± SD from three independent experiments.
Mentions: We also measured TAG levels in the roots of WT Arabidopsis plants grown under Pi-sufficient and Pi-depleted conditions. TAG levels in WT plants grown under Pi-depleted conditions were 5- to 6-fold higher in shoots and 1.5- to 2-fold higher in roots compared with those of plants grown under Pi-sufficient conditions (Figure 2A). It should be noted that we have also presented additional data here for shoot TAG levels for comparison with root TAG levels.

Bottom Line: Thus, the produced galactolipids are transferred to extraplastidial membranes to substitute for phospholipids.Moreover, the Arabidopsis starchless phosphoglucomutase mutant, pgm-1, accumulated higher TAG levels than did wild-type plants under Pi-depleted conditions.We generated transgenic plants that expressed a key gene involved in TAG synthesis using the Pi deficiency-responsive MGD3 promoter in wild-type and pgm-1 backgrounds.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology Yokohama, Japan.

ABSTRACT
Inorganic phosphate (Pi) depletion is a serious problem for plant growth. Membrane lipid remodeling is a defense mechanism that plants use to survive Pi-depleted conditions. During Pi starvation, phospholipids are degraded to supply Pi for other essential biological processes, whereas galactolipid synthesis in plastids is up-regulated via the transcriptional activation of monogalactosyldiacylglycerol synthase 3 (MGD3). Thus, the produced galactolipids are transferred to extraplastidial membranes to substitute for phospholipids. We found that, Pi starvation induced oil accumulation in the vegetative tissues of various seed plants without activating the transcription of enzymes involved in the later steps of triacylglycerol (TAG) biosynthesis. Moreover, the Arabidopsis starchless phosphoglucomutase mutant, pgm-1, accumulated higher TAG levels than did wild-type plants under Pi-depleted conditions. We generated transgenic plants that expressed a key gene involved in TAG synthesis using the Pi deficiency-responsive MGD3 promoter in wild-type and pgm-1 backgrounds. During Pi starvation, the transgenic plants accumulated higher TAG amounts compared with the non-transgenic plants, suggesting that the Pi deficiency-responsive promoter of galactolipid synthase in plastids may be useful for producing transgenic plants that accumulate more oil under Pi-depleted conditions.

No MeSH data available.


Related in: MedlinePlus