The COMATOSE ATP-Binding Cassette Transporter Is Required for Full Fertility in Arabidopsis

Footitt, Steven; Dietrich, Daniela; Fait, Aaron; Fernie, Alisdair R.; Holdsworth, Michael J.; Baker, Alison; Theodoulou, F. L.

doi:10.1104/pp.107.099903

Cited by 89 publications

(84 citation statements)

References 93 publications

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“…Measurements were made using NIH Image software. comatose alleles of PXA1, the ABC transporter likely to bring IBA into the peroxisome (Zolman et al, 2001b), display a stamen filament elongation delay that is rescued by NAA application (Footitt et al, 2007), suggesting that the auxin required for filament elongation (Cecchetti et al, 2008) is low in this tissue. Similarly, the ibr1 ibr3 ibr10 short-root-hair phenotype was fully rescued by exogenous IAA and NAA, but only partially rescued by the auxin transport inhibitors NPA or TIBA, consistent with the possibility that active auxin levels are low in root hair cells of this mutant.…”

Section: Discussionmentioning

confidence: 99%

Conversion of Endogenous Indole-3-Butyric Acid to Indole-3-Acetic Acid Drives Cell Expansion in Arabidopsis Seedlings

et al. 2010

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Genetic evidence in Arabidopsis (Arabidopsis thaliana) suggests that the auxin precursor indole-3-butyric acid (IBA) is converted into active indole-3-acetic acid (IAA) by peroxisomal b-oxidation; however, direct evidence that Arabidopsis converts IBA to IAA is lacking, and the role of IBA-derived IAA is not well understood. In this work, we directly demonstrated that Arabidopsis seedlings convert IBA to IAA. Moreover, we found that several IBA-resistant, IAA-sensitive mutants were deficient in IBA-to-IAA conversion, including the indole-3-butyric acid response1 (ibr1) ibr3 ibr10 triple mutant, which is defective in three enzymes likely to be directly involved in peroxisomal IBA b-oxidation. In addition to IBA-to-IAA conversion defects, the ibr1 ibr3 ibr10 triple mutant displayed shorter root hairs and smaller cotyledons than wild type; these cell expansion defects are suggestive of low IAA levels in certain tissues. Consistent with this possibility, we could rescue the ibr1 ibr3 ibr10 shortroot-hair phenotype with exogenous auxin. A triple mutant defective in hydrolysis of IAA-amino acid conjugates, a second class of IAA precursor, displayed reduced hypocotyl elongation but normal cotyledon size and only slightly reduced root hair lengths. Our data suggest that IBA b-oxidation and IAA-amino acid conjugate hydrolysis provide auxin for partially distinct developmental processes and that IBA-derived IAA plays a major role in driving root hair and cotyledon cell expansion during seedling development.

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Section: Discussionmentioning

confidence: 99%

Conversion of Endogenous Indole-3-Butyric Acid to Indole-3-Acetic Acid Drives Cell Expansion in Arabidopsis Seedlings

et al. 2010

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“…The molecular identity of the core b-oxidation pathway components and their physiological role in FA catabolism in postgerminative seedling growth in oilseeds are now well established (Graham, 2008;Theodoulou and Eastmond, 2012). Physiological understanding of b-oxidation in mature plant tissues has been defined in dark-induced (Kunz et al, 2009) or natural (Yang and Ohlrogge, 2009) senescence, reproductive development (Rylott et al, 2003;Footitt et al, 2007aFootitt et al, , 2007b, with respect to the biosynthesis of auxin (Strader and Bartel, 2011) and jasmonate (Goepfert and Poirier, 2007), and during storage TAG production (Slocombe et al, 2009;Kelly et al, 2013). The results of this study provide new insights into the regulation of the peroxisomal b-oxidation pathway and its role in membrane lipid homeostasis in leaves.…”

Section: Discussionmentioning

confidence: 99%

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

et al. 2014

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Triacylglycerol (TAG) metabolism is a key aspect of intracellular lipid homeostasis in yeast and mammals, but its role in vegetative tissues of plants remains poorly defined. We previously reported that PHOSPHOLIPID:DIACYLGLYCEROL ACYLTRANSFERASE1 (PDAT1) is crucial for diverting fatty acids (FAs) from membrane lipid synthesis to TAG and thereby protecting against FA-induced cell death in leaves. Here, we show that overexpression of PDAT1 enhances the turnover of FAs in leaf lipids. Using the trigalactosyldiacylglycerol1-1 (tgd1-1) mutant, which displays substantially enhanced PDAT1-mediated TAG synthesis, we demonstrate that disruption of SUGAR-DEPENDENT1 (SDP1) TAG lipase or PEROXISOMAL TRANSPORTER1 (PXA1) severely decreases FA turnover, leading to increases in leaf TAG accumulation, to 9% of dry weight, and in total leaf lipid, by 3-fold. The membrane lipid composition of tgd1-1 sdp1-4 and tgd1-1 pxa1-2 double mutants is altered, and their growth and development are compromised. We also show that two Arabidopsis thaliana lipin homologs provide most of the diacylglycerol for TAG synthesis and that loss of their functions markedly reduces TAG content, but with only minor impact on eukaryotic galactolipid synthesis. Collectively, these results show that Arabidopsis lipins, along with PDAT1 and SDP1, function synergistically in directing FAs toward peroxisomal b-oxidation via TAG intermediates, thereby maintaining membrane lipid homeostasis in leaves.

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“…This indicated that, besides a fast ATP-driven transport, OPDA also may enter peroxisomes by a passive route. Inside peroxisomes, an unknown critical threshold of JA exists, and levels below this threshold can affect fertility in different ways (McConn and Browse, 1996;Footitt et al, 2007). Generally, pollen defects become obvious by a significant deviation from Mendelian genetics.…”

Section: Discussionmentioning

confidence: 99%

Defects in Peroxisomal 6-Phosphogluconate Dehydrogenase Isoform PGD2 Prevent Gametophytic Interaction in Arabidopsis thaliana

et al. 2016

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We studied the localization of 6-phosphogluconate dehydrogenase (PGD) isoforms of Arabidopsis (Arabidopsis thaliana). Similar polypeptide lengths of PGD1, PGD2, and PGD3 obscured which isoform may represent the cytosolic and/or plastidic enzyme plus whether PGD2 with a peroxisomal targeting motif also might target plastids. Reporter-fusion analyses in protoplasts revealed that, with a free N terminus, PGD1 and PGD3 accumulate in the cytosol and chloroplasts, whereas PGD2 remains in the cytosol. Mutagenesis of a conserved second ATG enhanced the plastidic localization of PGD1 and PGD3 but not PGD2. Amino-terminal deletions of PGD2 fusions with a free C terminus resulted in peroxisomal import after dimerization, and PGD2 could be immunodetected in purified peroxisomes. Repeated selfing of pgd2 transfer (T-)DNA alleles yielded no homozygous mutants, although siliques and seeds of heterozygous plants developed normally. Detailed analyses of the C-terminally truncated PGD2-1 protein showed that peroxisomal import and catalytic activity are abolished. Reciprocal backcrosses of pgd2-1 suggested that missing PGD activity in peroxisomes primarily affects the male gametophyte. Tetrad analyses in the quartet1-2 background revealed that pgd2-1 pollen is vital and in vitro germination normal, but pollen tube growth inside stylar tissues appeared less directed. Mutual gametophytic sterility was overcome by complementation with a genomic construct but not with a version lacking the first ATG. These analyses showed that peroxisomal PGD2 activity is required for guided growth of the male gametophytes and pollen tube-ovule interaction. Our report finally demonstrates an essential role of oxidative pentose-phosphate pathway reactions in peroxisomes, likely needed to sustain critical levels of nitric oxide and/or jasmonic acid, whose biosynthesis both depend on NADPH provision.

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The COMATOSE ATP-Binding Cassette Transporter Is Required for Full Fertility in Arabidopsis

Cited by 89 publications

References 93 publications

Conversion of Endogenous Indole-3-Butyric Acid to Indole-3-Acetic Acid Drives Cell Expansion in Arabidopsis Seedlings

Conversion of Endogenous Indole-3-Butyric Acid to Indole-3-Acetic Acid Drives Cell Expansion in Arabidopsis Seedlings

Arabidopsis Lipins, PDAT1 Acyltransferase, and SDP1 Triacylglycerol Lipase Synergistically Direct Fatty Acids toward β-Oxidation, Thereby Maintaining Membrane Lipid Homeostasis

Defects in Peroxisomal 6-Phosphogluconate Dehydrogenase Isoform PGD2 Prevent Gametophytic Interaction in Arabidopsis thaliana

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