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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

Growth phenotypes and TAG accumulation in shoots of WT Arabidopsis plants grown under Pi- or N-depleted conditions. WT plants (10 d old) were transferred to MS agar containing 1% (w/v) sucrose with (+Pi; 1 mM) or without (−Pi; 0 mM) Pi for 10 d, or with (+N; 3.5 mM) or without (−N; 0 mM) N for 7 d. (A) Growth under Pi-depleted or N-depleted conditions. Bars = 1 cm. (B) TAG levels in shoots under Pi-depleted or N-depleted conditions. DW, dry weight. (C) Shoot fresh weight under Pi-depleted or N-depleted conditions. B, before transfer to Pi- or N-depleted conditions. (D) TAG content in shoots per seedling under N- or Pi-depleted conditions. Data are the means ± SD from three independent experiments.
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Figure 1: Growth phenotypes and TAG accumulation in shoots of WT Arabidopsis plants grown under Pi- or N-depleted conditions. WT plants (10 d old) were transferred to MS agar containing 1% (w/v) sucrose with (+Pi; 1 mM) or without (−Pi; 0 mM) Pi for 10 d, or with (+N; 3.5 mM) or without (−N; 0 mM) N for 7 d. (A) Growth under Pi-depleted or N-depleted conditions. Bars = 1 cm. (B) TAG levels in shoots under Pi-depleted or N-depleted conditions. DW, dry weight. (C) Shoot fresh weight under Pi-depleted or N-depleted conditions. B, before transfer to Pi- or N-depleted conditions. (D) TAG content in shoots per seedling under N- or Pi-depleted conditions. Data are the means ± SD from three independent experiments.

Mentions: We first compared the phenotypes and TAG levels of WT plants grown under N-depleted and Pi-depleted conditions (Figure 1). The seedlings grown under N-depleted conditions were relatively more chlorotic than seedlings grown under Pi-depleted conditions (Figure 1A), and the TAG levels in N-depleted plants after 7 d were 1.5-fold higher than in the Pi-depleted plants after 10 d (Figure 1B), suggesting that the higher accumulation of TAG during N depletion was a consequence of the rapid breakdown of photosynthetic membranes. Consistent with the phenotypes shown in Figure 1A, WT seedlings grown under N-depleted conditions for 7 d were very small, and their shoot fresh weight was half that of plants grown under N-sufficient or Pi-depleted conditions (Figure 1C). The TAG content per seedling in WT shoots under Pi-depleted conditions was ~1.5-fold higher than that of WT shoots under N-depleted conditions (Figure 1D).


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)

Growth phenotypes and TAG accumulation in shoots of WT Arabidopsis plants grown under Pi- or N-depleted conditions. WT plants (10 d old) were transferred to MS agar containing 1% (w/v) sucrose with (+Pi; 1 mM) or without (−Pi; 0 mM) Pi for 10 d, or with (+N; 3.5 mM) or without (−N; 0 mM) N for 7 d. (A) Growth under Pi-depleted or N-depleted conditions. Bars = 1 cm. (B) TAG levels in shoots under Pi-depleted or N-depleted conditions. DW, dry weight. (C) Shoot fresh weight under Pi-depleted or N-depleted conditions. B, before transfer to Pi- or N-depleted conditions. (D) TAG content in shoots per seedling under N- or Pi-depleted conditions. Data are the means ± SD from three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Growth phenotypes and TAG accumulation in shoots of WT Arabidopsis plants grown under Pi- or N-depleted conditions. WT plants (10 d old) were transferred to MS agar containing 1% (w/v) sucrose with (+Pi; 1 mM) or without (−Pi; 0 mM) Pi for 10 d, or with (+N; 3.5 mM) or without (−N; 0 mM) N for 7 d. (A) Growth under Pi-depleted or N-depleted conditions. Bars = 1 cm. (B) TAG levels in shoots under Pi-depleted or N-depleted conditions. DW, dry weight. (C) Shoot fresh weight under Pi-depleted or N-depleted conditions. B, before transfer to Pi- or N-depleted conditions. (D) TAG content in shoots per seedling under N- or Pi-depleted conditions. Data are the means ± SD from three independent experiments.
Mentions: We first compared the phenotypes and TAG levels of WT plants grown under N-depleted and Pi-depleted conditions (Figure 1). The seedlings grown under N-depleted conditions were relatively more chlorotic than seedlings grown under Pi-depleted conditions (Figure 1A), and the TAG levels in N-depleted plants after 7 d were 1.5-fold higher than in the Pi-depleted plants after 10 d (Figure 1B), suggesting that the higher accumulation of TAG during N depletion was a consequence of the rapid breakdown of photosynthetic membranes. Consistent with the phenotypes shown in Figure 1A, WT seedlings grown under N-depleted conditions for 7 d were very small, and their shoot fresh weight was half that of plants grown under N-sufficient or Pi-depleted conditions (Figure 1C). The TAG content per seedling in WT shoots under Pi-depleted conditions was ~1.5-fold higher than that of WT shoots under N-depleted conditions (Figure 1D).

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