Preventing Photochemistry in Culture Media by Long-Pass Light Filters Alters Growth of Cultured Tissues

Stasinopoulos, Triant C.; Hangarter, Roger P.

doi:10.1104/pp.93.4.1365

Cited by 135 publications

(129 citation statements)

References 25 publications

(31 reference statements)

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“…After stratification, seeds were placed under continuous light. To quantify IBA sensitivity, seedlings were grown on PNS plates under light filtered with yellow long-pass filters (to slow photochemical breakdown of indolic compounds; Stasinopoulos and Hangarter, 1990) for 4 to 5 d, transferred to new PNS plates with or without 10 mM IBA, and grown vertically under yellow light for an additional 3 to 4 d. Lateral roots emerged from the primary root were counted using a dissecting microscope; primary root lengths were measured with a ruler or using Image J 3.0 (http://rsbweb.nih.gov/ij/) after imaging seedlings using a Gel Doc System (Bio-Rad).…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

Disrupting Autophagy Restores Peroxisome Function to anArabidopsis lon2Mutant and Reveals a Role for the LON2 Protease in Peroxisomal Matrix Protein Degradation

et al. 2013

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Peroxisomes house critical metabolic reactions that are essential for seedling development. As seedlings mature, metabolic requirements change, and peroxisomal contents are remodeled. The resident peroxisomal protease LON2 is positioned to degrade obsolete or damaged peroxisomal proteins, but data supporting such a role in plants have remained elusive. Arabidopsis thaliana lon2 mutants display defects in peroxisomal metabolism and matrix protein import but appear to degrade matrix proteins normally. To elucidate LON2 functions, we executed a forward-genetic screen for lon2 suppressors, which revealed multiple mutations in key autophagy genes. Disabling core autophagy-related gene (ATG) products prevents autophagy, a process through which cytosolic constituents, including organelles, can be targeted for vacuolar degradation. We found that atg2, atg3, and atg7 mutations suppressed lon2 defects in auxin metabolism and matrix protein processing and rescued the abnormally large size and small number of lon2 peroxisomes. Moreover, analysis of lon2 atg mutants uncovered an apparent role for LON2 in matrix protein turnover. Our data suggest that LON2 facilitates matrix protein degradation during peroxisome content remodeling, provide evidence for the existence of pexophagy in plants, and indicate that peroxisome destruction via autophagy is enhanced when LON2 is absent.

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Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

Disrupting Autophagy Restores Peroxisome Function to anArabidopsis lon2Mutant and Reveals a Role for the LON2 Protease in Peroxisomal Matrix Protein Degradation

et al. 2013

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“…Plates containing auxin were incubated under yellow filters to slow the breakdown of indolic compounds (Stasinopoulos and Hangarter, 1990).…”

Section: Ethanol)mentioning

confidence: 99%

The Arabidopsis pxa1 Mutant Is Defective in an ATP-Binding Cassette Transporter-Like Protein Required for Peroxisomal Fatty Acid β-Oxidation

2001

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Peroxisomes are important organelles in plant metabolism, containing all the enzymes required for fatty acid ␤-oxidation. More than 20 proteins are required for peroxisomal biogenesis and maintenance. The Arabidopsis pxa1 mutant, originally isolated because it is resistant to the auxin indole-3-butyric acid (IBA), developmentally arrests when germinated without supplemental sucrose, suggesting defects in fatty acid ␤-oxidation. Because IBA is converted to the more abundant auxin, indole-3-acetic acid (IAA), in a mechanism that parallels ␤-oxidation, the mutant is likely to be IBA resistant because it cannot convert IBA to IAA. Adult pxa1 plants grow slowly compared with wild type, with smaller rosettes, fewer leaves, and shorter inflorescence stems, indicating that PXA1 is important throughout development. We identified the molecular defect in pxa1 using a map-based positional approach. PXA1 encodes a predicted peroxisomal ATP-binding cassette transporter that is 42% identical to the human adrenoleukodystrophy (ALD) protein, which is defective in patients with the demyelinating disorder X-linked ALD. Homology to ALD protein and other human and yeast peroxisomal transporters suggests that PXA1 imports coenzyme A esters of fatty acids and IBA into the peroxisome for ␤-oxidation. The pxa1 mutant makes fewer lateral roots than wild type, both in response to IBA and without exogenous hormones, suggesting that the IAA derived from IBA during seedling development promotes lateral root formation.Peroxisomes are small, ubiquitous organelles encased in a single lipid bilayer that contain hydrogen peroxide-producing oxidases and catalases to inactivate reactive molecules (for review, see Gerhardt, 1992; Kindl, 1993; Olsen, 1998; Tabak et al., 1999). Arabidopsis and other oilseed plants ␤-oxidize longchain fatty acids (LCFAs) in peroxisomes to provide energy during germination. Plant peroxisomes also contain enzymes that act in photorespiration (Olsen, 1998) and the catabolism of branched-chain amino acids (Gerhardt, 1992; Zolman et al., 2001). In addition, seedlings and senescing tissues contain specialized peroxisomes called glyoxysomes that convert acetyl-coenzyme A (CoA) to succinate, which is transported to the mitochondria where it fuels the tricarboxylic acid cycle (Gerhardt, 1992; Olsen, 1998).Mammals metabolize fatty acids in both mitochondria and peroxisomes, and each organelle shortens a distinct subset of fatty acids (Lazarow, 1993; Tabak et al., 1999). In contrast, plants and yeast catabolize fatty acids exclusively in peroxisomes (Gerhardt, 1992; Kindl, 1993). Because peroxisomes lack DNA, proteins required for ␤-oxidation and other peroxisomal processes are translated in the cytoplasm and then imported (Olsen, 1998;Subramani, 1998; Tabak et al., 1999). Peroxisomal matrix proteins contain one of two peroxisomal targeting signals (PTSs). The PTS1 is made up of the amino acids "SKL" (or a conserved variant) at the extreme C termini of peroxisomal matrix-bound proteins (Gould et al., 1989). The PEX5 recept...

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“…Light-induced IAA degradation can result in reduced growth for tissues that require auxin for cell proliferation (3,14). Light-induced degradation of hormonefree medium has also been reported recently (14).…”

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confidence: 99%

“…The growth of Arabidopsis roots was reduced when they were grown on hormone-free nutrient medium that had been previously exposed to light. These data suggest that some unidentified inhibitory material was photochemically produced and/or necessary growth factors were made unavailable (14). We have investigated the photochemistry involved in these lightinduced changes in medium composition because they could be an important source of variability in the growth ofcultured tissues.…”

mentioning

confidence: 99%

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Effect of Fe-Catalyzed Photooxidation of EDTA on Root Growth in Plant Culture Media

Hangarter¹,

Stasinopoulos²

1991

Plant Physiol.

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Light from fluorescent lamps can induce formaldehyde production and iron deficiency in plant nutrient culture medium. Formaldehyde is produced from EDTA when it is oxidized by the photochemical reduction of ferric iron and it can accumulate to inhibitory levels. The medium becomes iron deficient because iron becomes unchelated and forms an unavailable precipitate as EDTA is oxidized. The combination of light-induced formaldehyde production and loss of available iron reduces the ability of the culture media to support growth of Arabidopsis thaliana roots. Removing ultraviolet and blue wavelengths with a yellow acrylic filter is a simple and effective means of preventing Fecatalyzed photooxidation of EDTA in plant culture media.

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Preventing Photochemistry in Culture Media by Long-Pass Light Filters Alters Growth of Cultured Tissues

Cited by 135 publications

References 25 publications

Disrupting Autophagy Restores Peroxisome Function to anArabidopsis lon2Mutant and Reveals a Role for the LON2 Protease in Peroxisomal Matrix Protein Degradation

Disrupting Autophagy Restores Peroxisome Function to anArabidopsis lon2Mutant and Reveals a Role for the LON2 Protease in Peroxisomal Matrix Protein Degradation

The Arabidopsis pxa1 Mutant Is Defective in an ATP-Binding Cassette Transporter-Like Protein Required for Peroxisomal Fatty Acid β-Oxidation

Effect of Fe-Catalyzed Photooxidation of EDTA on Root Growth in Plant Culture Media

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