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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 Arabidopsis transgenic lines under Pi-sufficient and Pi-depleted conditions. Plants were grown on MS agar with 1% (w/v) sucrose for 10 d and then were transferred to MS agar containing 1% (w/v) sucrose with 1 mM Pi or without Pi for 10 d. (A) TAG levels in shoots per dry weight (DW) in WT, pgm-1, and transgenic plant lines under Pi-sufficient (light gray) and Pi-depleted (dark gray) conditions. (B,C) TAG content in shoots (B) and roots (C) per each seedling of WT, pgm-1, and transgenic plant lines, as in (A). Data are the mean ± SD from three independent experiments; a−dt-test significant at P < 0.05 vs. aWT under Pi-sufficient conditions, bWT under Pi-depleted conditions, cpgm-1 under Pi-sufficient conditions, or dpgm-1 under Pi-depleted conditions.
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Figure 6: TAG accumulation in Arabidopsis transgenic lines under Pi-sufficient and Pi-depleted conditions. Plants were grown on MS agar with 1% (w/v) sucrose for 10 d and then were transferred to MS agar containing 1% (w/v) sucrose with 1 mM Pi or without Pi for 10 d. (A) TAG levels in shoots per dry weight (DW) in WT, pgm-1, and transgenic plant lines under Pi-sufficient (light gray) and Pi-depleted (dark gray) conditions. (B,C) TAG content in shoots (B) and roots (C) per each seedling of WT, pgm-1, and transgenic plant lines, as in (A). Data are the mean ± SD from three independent experiments; a−dt-test significant at P < 0.05 vs. aWT under Pi-sufficient conditions, bWT under Pi-depleted conditions, cpgm-1 under Pi-sufficient conditions, or dpgm-1 under Pi-depleted conditions.

Mentions: We analyzed TAG levels in vegetative tissues of WT, pgm-1, and transgenic plants (Figure 6). Compared with WT plants under Pi-sufficient conditions, TAG levels in pgm-1 under Pi-sufficient and Pi-depleted conditions were 1.8-fold and 13-fold higher, respectively (Figure 6A). Moreover, TAG levels in DGAT1_pgm-1 line 2, DGAT2_pgm-1 line 2, and PDAT1_pgm-1 line 3 transgenic lines under Pi-depleted conditions were 26-,16-, and 23-fold higher, respectively, than WT under Pi-sufficient conditions (Figure 6A). Moreover, the TAG content in shoots per seedling of pgm-1, DGAT1_pgm-1 line 2, DGAT2_pgm-1 line 2, and PDAT1_pgm-1 line 3 transgenic lines under Pi-depleted conditions was 9.5-, 19-, 12-, and 23-fold higher, respectively, than that of WT seedlings under Pi-sufficient conditions, and the TAG content was 1.8-, 3.5-, 2.3-, and 4.3-fold higher, respectively, than that of WT seedlings under Pi-depleted conditions (Figure 6B).


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 Arabidopsis transgenic lines under Pi-sufficient and Pi-depleted conditions. Plants were grown on MS agar with 1% (w/v) sucrose for 10 d and then were transferred to MS agar containing 1% (w/v) sucrose with 1 mM Pi or without Pi for 10 d. (A) TAG levels in shoots per dry weight (DW) in WT, pgm-1, and transgenic plant lines under Pi-sufficient (light gray) and Pi-depleted (dark gray) conditions. (B,C) TAG content in shoots (B) and roots (C) per each seedling of WT, pgm-1, and transgenic plant lines, as in (A). Data are the mean ± SD from three independent experiments; a−dt-test significant at P < 0.05 vs. aWT under Pi-sufficient conditions, bWT under Pi-depleted conditions, cpgm-1 under Pi-sufficient conditions, or dpgm-1 under Pi-depleted conditions.
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Figure 6: TAG accumulation in Arabidopsis transgenic lines under Pi-sufficient and Pi-depleted conditions. Plants were grown on MS agar with 1% (w/v) sucrose for 10 d and then were transferred to MS agar containing 1% (w/v) sucrose with 1 mM Pi or without Pi for 10 d. (A) TAG levels in shoots per dry weight (DW) in WT, pgm-1, and transgenic plant lines under Pi-sufficient (light gray) and Pi-depleted (dark gray) conditions. (B,C) TAG content in shoots (B) and roots (C) per each seedling of WT, pgm-1, and transgenic plant lines, as in (A). Data are the mean ± SD from three independent experiments; a−dt-test significant at P < 0.05 vs. aWT under Pi-sufficient conditions, bWT under Pi-depleted conditions, cpgm-1 under Pi-sufficient conditions, or dpgm-1 under Pi-depleted conditions.
Mentions: We analyzed TAG levels in vegetative tissues of WT, pgm-1, and transgenic plants (Figure 6). Compared with WT plants under Pi-sufficient conditions, TAG levels in pgm-1 under Pi-sufficient and Pi-depleted conditions were 1.8-fold and 13-fold higher, respectively (Figure 6A). Moreover, TAG levels in DGAT1_pgm-1 line 2, DGAT2_pgm-1 line 2, and PDAT1_pgm-1 line 3 transgenic lines under Pi-depleted conditions were 26-,16-, and 23-fold higher, respectively, than WT under Pi-sufficient conditions (Figure 6A). Moreover, the TAG content in shoots per seedling of pgm-1, DGAT1_pgm-1 line 2, DGAT2_pgm-1 line 2, and PDAT1_pgm-1 line 3 transgenic lines under Pi-depleted conditions was 9.5-, 19-, 12-, and 23-fold higher, respectively, than that of WT seedlings under Pi-sufficient conditions, and the TAG content was 1.8-, 3.5-, 2.3-, and 4.3-fold higher, respectively, than that of WT seedlings under Pi-depleted conditions (Figure 6B).

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