| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
First published online April 17, 2003; 10.1104/pp.102.018622 Plant Physiology 132:748-756 (2003) © 2003 American Society of Plant Biologists Expression of Antisense Acyl Carrier Protein-4 Reduces Lipid Content in Arabidopsis Leaf Tissue1Department of Food Science and Human Nutrition, University of Illinois, 259 Edward R. Madigan Library, 1201 West Gregory Drive, Urbana, Illinois 61801 (J.K.B., N.J.E.); and Department of Biochemistry, University of Nevada, Reno, Nevada 89557 (D.K.S.)
Arabidopsis plants were transformed with acyl carrier protein (ACP)-4 in antisense conformation driven by the cauliflower mosaic virus 35S promoter. It was hypothesized that reduction of ACP4 in leaf tissue would result in a reduction in lipid biosynthesis and, in addition, affect fatty acid composition and leaf physiology. Several transgenic lines have been generated with reduced ACP4 protein in leaf tissue. Dramatic reductions in ACP4 resulted in a reduction of leaf lipid content (22%–60%) based on fresh leaf weight and a bleached appearance and reduced photosynthetic efficiency. In addition, a decrease in 16:3 as a percentage of the total fatty acid composition was noted. There were no changes in leaf lipid class distribution; however, there was a decrease in the relative amount of 16:3 in monogalactosyldiacylglycerol. These results suggest that ACP4 plays a major role in the biosynthesis of fatty acids for chloroplast membrane development. Alterations in the ACP isoform profile of Arabidopsis leaf also appear to alter the flow of fatty acids between the prokaryotic and eukaryotic pathways for assembly of galactolipids. However, it has not yet been determined if the changes in fatty acid composition are due to changes in the profile of ACP isoforms, or if they are actually a reaction to a reduction in fatty acid precursors.
In higher plants, fatty acids have many diverse and important functions. They are critical components of membrane lipids and cuticular waxes in addition to being precursors to several signaling and defense compounds such as jasmonate (Somerville et al., 2000  ). In many plants, especially oilseeds, fatty acids are also stored in triacylglycerides as a concentrated energy source for use during seed germination. De novo synthesis of fatty acids in plants takes place primarily in plastids (Ohlrogge et al., 1979). The pathways for plant fatty acid and lipid biosynthesis are well elucidated (for review, see Harwood, 1996). However, little is known about how these pathways are regulated.
Acyl carrier protein (ACP) is a critical cofactor for fatty acid biosynthesis in higher plants. This small (9 kD) acidic protein carries growing acyl chains through the various enzymatic steps in fatty acid biosynthesis. All higher plants that have been studied contain several isoforms of ACP, some of which are expressed constitutively (in all tissues) and others that are expressed in a tissue-specific manner (Battey and Ohlrogge, 1990
Arabidopsis has five isoforms of plastidial ACP (Mekhedov et al., 2000
In a study of the regulation of ACP isoforms in Arabidopsis, Bonaventure and Ohlrogge (2002
Generation and Phenotype of Antisense ACP4 Transgenic Plants Thirty-two independent kanamycin-resistant plants were selected by screening T1 seeds generated from transformation of Arabidopsis with antisense ACP4. These plants will henceforth be referred to as leaf major isoform antisense. The general appearance of the plants was compared with that of wild-type plants grown side by side at 4 weeks after germination. Of the 32 T1 transgenic plants, 20 exhibited a bleached appearance (Fig. 1). This phenotype varied in severity from plant to plant. In some plants, only the outer edges of leaves were bleached, whereas others had a few leaves that were bleached throughout along with green leaves. Certain plants were bleached in appearance throughout all green tissues; the severity of bleaching ranged from slightly less green than the wild-type plants to very yellow. Many of the bleached transgenic plants were also smaller in size compared with wild-type and nonbleached transgenic plants. In addition, characteristics such as delayed bolting and shorter bolts were noted in the bleached transgenic plants. All of the transgenic plants produced seeds. However, some severely bleached plants were very small and only produced approximately 10% of the normal number of seeds.
Seeds (T2) from 12 of the 20 bleached transgenic plants were screened on Murashige and Skoog agar with kanamycin. Four resistant seedlings from each line were transferred to soil-less mix and put in a growth chamber with regulated temperature, light, and humidity. Surprisingly, the bleached phenotype seen in the T1 plants did not carry through to all of the T2 plants. In some cases, the bleached phenotype was noted in one or two of the four T2 plants. However, in some cases, none of the four progeny from a bleached parent had a bleached appearance. Only in a few of the lines was a bleached appearance noted in all four T2 progeny. Because only approximately 25 seeds were plated per line, segregation analysis could not be determined. However, our observation with the small number of seeds that were plated was that most of the lines did not segregate in a Mendelian fashion expected for a single insert. Based on further western and lipid analysis of leaf tissue from T2 progeny, the bleached phenotype seemed to segregate together with reduced ACP4 protein and reduced leaf lipid content. Therefore, it is suspected that in at least some of the plants, multiple copies of the transgene exist and that all of the copies must be present to achieve reduced ACP4 and the associated phenotype. However, the loss of phenotype in some plants could also be due to differences in environmental conditions (mainly light intensity) during growth of T1 versus T2 plants or to transgene instability.
Western-blot analysis of protein from LMIA leaf tissue indicates that 0.5- to 4-fold reductions in ACP4 were achieved (Fig. 2). The ACP4 band was barely visible in extracts with 3- to 4-fold reductions as determined by measuring the mean intensity level. Levels of the other leaf ACP isoforms, ACP2 and ACP3, were not altered except in those transgenic plants where there was a 3- to 4-fold reduction in ACP4. In those plants, ACP2 and ACP3 levels were reduced by 25% to 50%. It is possible that these reductions are due to the antisense ACP4 mRNA; ACP4 is 50% similar to ACP2 and ACP3 at the cDNA level. Otherwise, these reductions may be a response to the reduction in ACP4 or a secondary response to low lipid levels. In addition, because the transgenic plants were chlorotic in many cases, and chloroplast levels are often correlated with chlorophyll content, the idea that the apparent reduction in ACP2 and ACP3 levels may actually be reflecting lower chloroplast levels cannot be discounted. There was a visual correlation between the severity of the bleached phenotype and the decrease in ACP4 protein. Even leaves within the same plant showed variability in the reduction of ACP4. This was confirmed by western-blot analysis; when protein extracts from a bleached leaf were run on a gel next to protein extracts from a less bleached leaf from the same plant, there was a difference in the reduction of ACP4 between the two leaf protein extracts (data not shown).
Transgenic plants with bleached phenotype and reduced ACP4 also had lower lipid content (22%–68% lower lipid by fresh weight) compared with wild-type plants (Fig. 3A). Again, the plants that had leaves with the low lipid content were also bleached in appearance. This suggests that the reduction in leaf lipid content is due to reductions in ACP levels. Those transgenic plants with reduced lipid content also had lower 16:3 as a percentage of the total fatty acids (Fig. 3B) compared with wild-type leaves. Because 16:3 was lower in the transgenic plants with reduced lipid, we hypothesized that there may be a decrease in monogalactosyldiacylglycerol (MGDG) in lipids from these plants. However, when an equal amount of total lipid was spotted and run on a thin-layer chromatography (TLC) plate, there were no dramatically visible alterations in polar leaf lipid classes of transgenic plants compared with wild-type plants when visualized with iodine vapor (Fig. 4). To further investigate the reason for the lower 16:3 content in leaf lipids of transgenic plants, lipids were again run on TLC plates. Portions of the silica in each lane corresponding to known lipid standards were scraped from the plates, and the fatty acid composition of each lipid was analyzed. Because most of the 16:3 in Arabidopsis leaf tissue is found on the sn-2 position of MGDG, it was of particular interest to determine the amount of 16:3 in MGDG from LMIA plants (Table I). MGDG content was, on average, calculated to be lower in transgenic plants compared with wild-type plants, but it was not found to be statistically lower due to the high variation of measurement. The variability is directly related to the high variability in recovery of the lipid classes from the silica. To confirm that the ratios of polar leaf lipids were not different between wild-type and LMIA plants, lipid extracts from wild-type and LMIA-25 leaf tissue were analyzed by HPLC. The HPLC method that was used sufficiently separated MGDG, digalactosyldiacylglycerol (DGDG), sulfaquinovosyldiacylglycerol, phosphatidylethanolamine, and phosphatidylglycerol (PG). However, PI could not be separated from PG; therefore, it is reported as part of PG. The variation in analysis by HPLC was much lower (Table II) than the TLC analysis. There was very little difference in the polar lipid profile between wild-type and LMIA-25 leaf lipids even though lipid content and chlorophyll content of LMIA-25 leaf tissue was lower. This confirms visual results from TLC plates (Fig. 4) and the results from TLC analysis of polar leaf lipids. Although there was not a significant decrease in the relative percentage of MGDG or any of the other polar lipids from LMIA plants, there was a reduction of the percentage of 16:3 in MGDG with a concomitant increase in 18:3 in MGDG from LMIA leaf tissue. In addition, there was an overall increase in the C18:C16 ratio in LMIA plants.
Because plants with reduced ACP4 and lower lipid content were bleached, we hypothesized that photosynthesis might be affected. The Fv/Fm of dark-adapted leaves from wild-type and LMIA plants was measured. Wild-type Arabidopsis leaves had an average dark-adapted Fv/Fm value of 0.850, as did the LMIA plants that were green and did not have dramatically reduced ACP4 or lipid content. However, for those plants with a bleached phenotype, the Fv/Fm average was 0.796 (significantly lower, P = 0.0003), indicating that the potential quantum efficiency of PSII was disrupted (Fig. 5).
There are three ACP isoforms (ACP2, ACP3, and ACP4) present in Arabidopsis leaf tissue at levels sufficient for detection by western-blot analysis. Of these isoforms, ACP4 is the most abundant; thus, a reduction in ACP4 constitutes a major reduction in total ACP available as a cofactor for fatty acid biosynthesis. Plants with reduced ACP4 had reduced lipid content. Therefore, the reduction in leaf lipid content is likely due to the reduction in total ACP. This is consistent with in vitro studies demonstrating that immunoprecipitation of ACP from spinach (Spinacia oleracea) leaf homogenates inhibited fatty acid synthesis (Ohlrogge et al., 1979 ). The levels of ACP necessary to support fatty acid biosynthesis in leaf tissue have not been determined. However, analysis of free versus acylated ACP levels in spinach revealed that approximately 60% of the ACPs are present in a nonacylated form (Post-Beittenmiller et al., 1991), indicating that the normal pool of ACPs is sufficient to support fatty acid synthesis. In addition, increases in ACP protein levels in tobacco (Nicotiana tabacum) and Arabidopsis leaf tissue did not increase leaf lipid content (Post-Beittenmiller et al., 1989b; Branen et al., 2001).
Because ACP is a critical cofactor for fatty acid biosynthesis, it might be expected that reduction of one isoform in a particular tissue might result in compensatory increases in the other ACP isoforms. However, levels of ACP2 and ACP3 in transgenic leaf tissue with reduced ACP4 were not increased in comparison with wild-type levels of these proteins. As previously mentioned, our analysis was based on equal loading of tissue extracts based on leaf fresh weight; we did not control for chlorophyll or chloroplast content. Thus, it is possible that although overall levels of ACP2 and ACP3 did not increase, levels of these isoforms in the chloroplast were actually increased. However, a lack of response of ACP2 and ACP3 to decreased ACP4 would be consistent with evidence that these isoforms are differentially regulated. For example, ACP4 mRNA levels are increased by light (Bonaventure and Ohlrogge, 2002 In addition to a decrease in total lipid content, transgenic plants with reduced ACP4 also had a lower 16:3 content. In the initial screening of T1 plants, lower 16:3 levels seemed to be compensated for by higher 16:0 levels. However, in subsequent analysis of T2 plants, the lower 16:3 actually seemed to result in an increase in C18 fatty acids, with an overall increase in the C18:C16 ratio (Table I). The lower 16:3 content would be indicative of lower MGDG levels, which might be expected based on the chlorotic appearance of the transgenic plants. However, it was found that the levels of chloroplast lipids, including MGDG, as a fraction of the total lipid were actually similar to levels in wild-type plants. The lower 16:3 is attributed to lower 16:3 on the MGDG moiety. This leads us to conclude that there is a decrease in the proportion of MGDG synthesized through the prokaryotic pathway.
A shift in the flux of fatty acid from the prokaryotic to the eukaryotic pathways has been noted in several Arabidopsis mutants. A common theme observed among these plants is that although the prokaryotic pathway was interrupted, the balance of chloroplast lipids normally produced through the prokaryotic pathway was maintained through increased synthesis of these lipids via the eukaryotic pathway. The act1 mutant, deficient in chloroplast glycerol-3-phosphate acyltransferase (G-3-PAT) activity, had dramatically reduced flux through the prokaryotic pathway (Kunst et al., 1988 Although it is becoming clear that there is close coordination between the prokaryotic and eukaryotic pathways, the mechanisms mediating partitioning of fatty acids between the two pathways are still not understood. There are several possible explanations for the shift in flux between the two pathways in LMIA plants with reduced lipid. One possibility may be that activity or expression of chloroplast lipid biosynthetic enzymes such as G-3-PAT, the first enzyme to direct lipids to the prokaryotic pathway, is lowered in response to the reduction in fatty acid biosynthesis. Because plastid G-3-PAT acts at the branch point of fatty acid incorporation between the prokaryotic and eukaryotic pathways, lower G-3-PAT activity could result in higher flux through the eukaryotic pathway. This would be consistent with the results seen with the act1 mutant.
Another possibility still being investigated is that alterations in the ACP isoform profile may influence the balance between the prokaryotic and eukaryotic pathways because of possible differential activity of enzymes toward acyl-ACP isoforms or by another unknown mechanism. In vitro specificity for acyl-ACP isoforms has been demonstrated by spinach oleoyl-ACP thioesterase and acyl-ACP-G-3-PAT (Guerra et al., 1986
Transgenic plants with lower ACP4 levels and reduced leaf lipid content displayed varying degrees of a bleached phenotype, smaller size, and shorter bolts. Measurement of leaf Fv/Fm revealed that photosynthesis is affected in the bleached transgenic plants. Studies of Arabidopsis lipid mutants have demonstrated that fatty acid composition and total lipid content play an important role in chloroplast membrane structure and photosynthetic capability. Previous reports demonstrate that chloroplast structure is altered but overall photosynthesis, growth, and development of plants is not severely affected by altering fatty acid composition when polyunsaturated fatty acids and the relative proportion of chloroplast lipids are maintained at near-normal levels (Browse et al., 1989
An 80% decrease in biotin carboxylase protein level was noted in an antisense transgenic tobacco plant (Shintani et al., 1997 In conclusion, reduction of ACP4, the major ACP isoform in Arabidopsis leaf tissue, led to a decrease in total leaf lipids. In addition, there appeared to be an increase in the proportion of lipids packaged via the eukaryotic pathway in plants with reduced leaf lipids, but the mechanism for this alteration is unknown. Size, appearance, and photosynthetic capability were compromised in transgenic plants with reduced ACP4, probably due to the decrease in total lipid biosynthesis. These results indicate that ACP4 plays a major role in the biosynthesis of fatty acids for chloroplast membrane lipids. Transgenic plant development is currently under way to generate plants with overexpressed ACP1 and reduced ACP4 in leaf tissue to answer the question of whether the LMIA phenotype is due simply to an overall reduction in the ACP pool or if it may be a specific response to reduction in the ACP4 isoform.
Plant Growth Conditions To grow Arabidopsis ecotype Columbia plants for transformation, seeds were directly germinated in a soil-less mix (Sunshine Mix LC1) and grown in a temperature-controlled room at 22°C ± 1°C with a 16-h-light (55 µmol m–2 s–1) photoperiod. After transformation, T1 seeds were surface sterilized and screened on agar plates consisting of 4.3 g L–1 Murashige and Skoog basal salt mixture, 0.5 g L–1 MES (pH 5.7), 9.6 g L–1 agar (Becton-Dickinson, Sparks, MD), and 50 mg L–1 kanamycin. Resistant seedlings were transferred to soil, and T1 plants were grown in the same temperature-controlled room. Seeds from T1 plants were also screened on Murashige and Skoog agar with kanamycin. Resistant T2 plants were transferred to soil after 10 d and were placed in a growth chamber (Percival Scientific, Boone, IA) at 22°C and 60% humidity with a 16-h-light (128 µmol m–2 s–1) photoperiod. Western analysis of ACP protein levels and total lipid content and composition analysis was performed on T1 plants. All further analyses, including further western analysis and lipid analysis, were performed using tissue from T2 plants.
The Arabidopsis ACP4 cDNA, including some of the 5'-untranslated region, was cloned in antisense conformation into the vector p1079 behind the cauliflower mosaic virus 35S promoter. The resulting construct was designated p0424A. The 1.6-kb NotI fragment containing 35S-ACP4 (antisense) was subcloned into the binary vector pART27 (Gleave, 1992
Tissue from transgenic plants was analyzed for alterations in ACP protein levels by western blot as described by Battey and Ohlrogge (1990
Total lipid was extracted from leaves by the method of Bligh and Dyer (1959
Leaf polar lipid classes were separated by TLC on silica gel plates (60 Å, 250 µm, Whatman, Maidstone, UK) with either chloroform:methanol:acetic acid:water (170:30:20:7 [v/v/v/v]) as a solvent system or on NH4SO4-impregnated silica gel plates with acetone:toluene:water (91:30:8 [v/v]; Kahn and Williams, 1977 For HPLC separation of polar leaf lipids, lipid extracts were dried, resuspended in chloroform, and filtered. Lipids were separated on a 3.9x 300-mm silicic acid column (10 µm Porasil, Supelco). A Hewlett-Packard 1050 autosampler combined with an HP 1050 pump were utilized for injection and gradient control. The solvent system, adapted from Demandre et al. (1985), consisted of a linear gradient from 100% (w/v) solvent A (isopropanol:hexane [4:3 {v/v}] with 2 mM ammonium acetate) to 100% solvent B (isopropanol:hexane:water [8:6:1.5 {v/v}] with 2 mM ammonium acetate) for 15 min, isocratic flow of 100% solvent B for 10 min, a linear gradient returning to 100% (w/v) solvent A in 10 min, followed by recovery of the column in 100% (w/v) solvent A for 5 min for a total run time of 40 min. The flow rate was 1 mL min–1 during the entire analysis. Lipids were detected using a Sedex55 evaporative light scattering detector (S.E.D.E.R.E., Alfortville, cedex, France) operated with a nebulizer gas (N2) pressure of 2.4 Bar and a temperature of 42°C; gain was set to 7. Quantification was achieved by developing standard curves using known standards. Data were collected and analyzed using Hewlett-Packard HPLC 2D Chemstations.
Fluorescence measurements were taken from leaves of 6-week-old T2 plants using a fluorescence monitoring system (FMS2, Hansatech Instruments, Norfolk, UK). Leaves were dark adapted for 2 min, then placed under a modulating measuring beam with a photon flux density of 100 µmol m–2 s–1 to determine F0, the initial fluorescence. The leaf was then pulsed with a saturating light pulse to measure the maximum fluorescence, Fm. The ratio of Fv/Fm was calculated where Fv = Fm – F0.
Our thanks to Dr. John Ohlrogge for providing the ACP antibody. We would also like to thank Lisa Ainsworth and Dr. Steven Long for assistance with leaf fluorescence measurements and for use of the fluorometer. Received December 3, 2002; returned for revision December 8, 2002; accepted December 8, 2002.
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.102.018622.
1 This work was supported in part by the State of Illinois Competitive Funding for Food and Agricultural Research. * Corresponding author; e-mail engeseth{at}uiuc.edu; fax 217–244–7877.
Bao X, Focke M, Pollard M, Ohlrogge JB (2000) Understanding in vivo carbon precursor supply for fatty acid synthesis in leaf tissue. Plant J 22: 39–50[CrossRef][Web of Science][Medline] Battey JF, Ohlrogge JB (1990) Evolutionary and tissue-specific control of expression of multiple acyl-carrier protein isoforms in plants and bacteria. Planta 180: 352–360[CrossRef][Web of Science] Bligh EG, Dyer WJ (1959) A rapid method of total lipid extraction and purification. Can J Biochem Physiol 37: 911–917
Bonaventure G, Ohlrogge JB (2002) Differential regulation of mRNA levels of acyl carrier protein isoforms in Arabidopsis. Plant Physiol 128: 223–235
Branen JK, Chiou T-J, Engeseth NJ (2001) Overexpression of acyl carrier protein-1 alters fatty acid composition of leaf tissue in Arabidopsis. Plant Physiol 127: 222–229
Browse J, Kunst L, Anderson S, Hugly S, Somerville C (1989) A mutant of Arabidopsis deficient in the chloroplast 16: 1/18:1 desaturase. Plant Physiol 90: 522–529 Browse J, Roughan PG, Slack CR (1981) Light control of fatty acid synthesis and diurnal fluctuations of fatty acid composition in leaves. Biochem J 196: 347–354[Web of Science][Medline] Clough SJ, Bent AF (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J 16: 735–743[CrossRef][Web of Science][Medline] Demandre C, Tremolieres A, Justin A, Mazliak P (1987) Analysis of molecular species of plant polar lipids by high-performance and gas liquid chromatography. Phytochemistry 24: 481–485[CrossRef] Dörmann P, Hoffman-Benning S, Balbo I, Benning C (1995) Isolation and characterization of an Arabidopsis mutant deficient in the thylakoid lipid digalactosyl diacylglycerol. Plant Cell 7: 1801–1810[Abstract] Gleave AP (1992) A versatile binary vector system with a T-DNA organizational structure conducive to efficient integration of cloned DNA into the plant genome. Plant Mol Biol 20: 1203–1207[CrossRef][Web of Science][Medline]
Guerra DJ, Ohlrogge JB, Frentzen M (1986) Activity of acyl carrier protein isoforms in reactions of plant fatty acid metabolism. Plant Physiol 82: 448–453
Härtel H, Dörmann P, Benning C (2000) DGD1-independent biosynthesis of extraplastidic galactolipids after phosphate deprivation in Arabidopsis. Proc Natl Acad Sci USA 97: 10649–10654 Harwood JL (1996) Recent advances in the biosynthesis of plant fatty acids. Biochim Biophys Acta 1301: 7–56[Medline]
Hlou
Jarvis P, Dörmann P, Peto CA, Lutes L, Benning C, Chory J (2000) Galactolipid deficiency and abnormal chloroplast development in the Arabidopsis MGD synthase1 mutant. Proc Natl Acad Sci USA 97: 8175–8179 Kahn JU, Williams JP (1977) Improved thin-layer chromatographic method for the separation of major phospholipids and glycolipids from plant lipid extracts and phosphatidyl glycerol and bis(monoacylgyceryl) phosphate from animal extracts. J Chromatogr 140: 179–185[CrossRef][Web of Science][Medline]
Klaus D, Härtel H, Fitzpatrick LM, Froehlich JE, Hubert J, Benning C, Dörmann P (2002) Digalactosyldiacylglycerol synthesis in chloroplasts of the Arabidopsis dgd1 mutant. Plant Physiol 128: 885–895
Kunst L, Browse JA, Somerville CR (1988) Altered regulation of lipid biosynthesis in a mutant of Arabidopsis deficient in chloroplast glycerol-3-phosphate acyltransferase activity. Proc Natl Acad Sci USA 85: 4143–4147
Kunst L, Browse J, Somerville C (1989) Altered chloroplast structure and function in a mutant of Arabidopsis deficient in glycerol-3-phosphate acyltransferase activity. Plant Physiol 90: 846–853 Lamppa G, Jacks C (1991) Analysis of two linked genes coding for the acyl carrier protein (ACP) from Arabidopsis thaliana (Columbia). Plant Mol Biol 16: 469–474[Medline] Lichtenthaler HK (1987) Chlorophylls and carotenoids: pigments of photosynthetic membranes. Methods Enzymol 148: 350–382[Web of Science] Lightner J, James DW Jr, Dooner HK, Browse J (1994a) Altered body morphology is caused by increased stearate levels in a mutant of Arabidopsis. Plant J 6: 401–412[CrossRef] Lightner J, Wu J, Browse J (1994b) A mutant of Arabidopsis with increased levels of stearic acid. Plant Physiol 106: 1443–1451[Abstract] McConn M, Browse J (1998) Polyunsaturated membranes are required for photosynthetic competence in a mutant of Arabidopsis. Plant J 154: 521–530
Mekhedov S, Martinez de Ilarduya O, Ohlrogge J (2000) Toward a functional catalog of the plant genome: a survey of genes for lipid biosynthesis. Plant Physiol 122: 389–401
Miquel M, Browse J (1992) Arabidopsis mutants deficient in polyunsaturated fatty acid synthesis. J Biol Chem 267: 1502–1509
Mou Z, He Y, Dai Y, Liu X, Li J (2000). Deficiency in fatty acid synthase leads to premature cell death and dramatic alterations in plant morphology. Plant Cell 12: 405–417
Ohlrogge JB, Kuhn DN, Stumpf PK (1979) Subcellular localization of acyl carrier protein in leaf protoplasts of Spinacia oleracea. Proc Natl Acad Sci USA 76: 1194–1198
Post-Beittenmiller D, Jaworski JG, Ohlrogge JB (1991) In vivo pools of free and acylated acyl carrier proteins in spinach: evidence for sites of regulation of fatty acid biosynthesis. J Biol Chem 266: 1858–1865
Post-Beittenmiller MA, Hlou
Post-Beittenmiller MA, Schmid KM, Ohlrogge JB (1989b) Expression of holo and apo forms of spinach acyl carrier protein-1 in leaves of transgenic tobacco plants. Plant Cell 1: 889–899 Rock CO, Cronan JE (1981) Acyl carrier protein from Escherichia coli. Methods Enzymol 71: 341–351 Shintani DK (1996) How plants manage their fatty assets: a study into the organization and regulation of the plant fatty acid biosynthetic pathway. PhD thesis. Michigan State University, East Lansing Shintani DK, Ohlrogge JB (1994) The characterization of a mitochondrial acyl carrier protein isoform isolated from Arabidopsis thaliana. Plant Physiol 104: 1221–1229[Abstract] Shintani D, Roesler K, Shorrosh B, Savage L, Ohlrogge J (1997) Antisense expression and overexpression of biotin carboxylase in tobacco leaves. Plant Physiol 114: 881–886[Abstract] Somerville C, Browse J, Jaworski JG, Ohlrogge JB (2000) Lipids: chapter 10 In BB Buchanan, W Gruissem, RL Jones, eds, Biochemistry and Molecular Biology of Plants. American Society of Plant Physiologists, Rockville, MD, pp 456–527 Suh MC, Schultz DJ, Ohlrogge JB (1999) Isoforms of acyl carrier protein involved in seed specific fatty acid synthesis. Plant J 17: 679–688[Medline] This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|
TOP
ABSTRACT
RESULTS
ek-Radoj
i
et al., 1992
