Rinaldi, Mauro A.Patel, Ashish B.Park, JaeseokLee, KoeunStrader, Lucia C.Bartel, Bonnie2018-07-102018-07-102016Rinaldi, Mauro A., Patel, Ashish B., Park, Jaeseok, et al.. "The Roles of β-Oxidation and Cofactor Homeostasis in Peroxisome Distribution and Function in Arabidopsis thaliana." <i>Genetics,</i> 204, no. 3 (2016) The Genetics Society of America: 1089-1115. https://doi.org/10.1534/genetics.116.193169.https://hdl.handle.net/1911/102357Key steps of essential metabolic pathways are housed in plant peroxisomes. We conducted a microscopy-based screen for anomalous distribution of peroxisomally targeted fluorescence in Arabidopsis thaliana. This screen uncovered 34 novel alleles in 15 genes affecting oil body mobilization, fatty acid β-oxidation, the glyoxylate cycle, peroxisome fission, and pexophagy. Partial loss-of-function of lipid-mobilization enzymes conferred peroxisomes clustered around retained oil bodies without other notable defects, suggesting that this microscopy-based approach was sensitive to minor perturbations, and that fatty acid β-oxidation rates in wild type are higher than required for normal growth. We recovered three mutants defective in PECTIN METHYLESTERASE31, revealing an unanticipated role in lipid mobilization for this cytosolic enzyme. Whereas mutations reducing fatty acid import had peroxisomes of wild-type size, mutations impairing fatty acid β-oxidation displayed enlarged peroxisomes, possibly caused by excess fatty acid β-oxidation intermediates in the peroxisome. Several fatty acid β-oxidation mutants also displayed defects in peroxisomal matrix protein import. Impairing fatty acid import reduced the large size of peroxisomes in a mutant defective in the PEROXISOMAL NAD+ TRANSPORTER (PXN), supporting the hypothesis that fatty acid accumulation causes pxn peroxisome enlargement. The diverse mutants isolated in this screen will aid future investigations of the roles of β-oxidation and peroxisomal cofactor homeostasis in plant development.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articleperoxisomelipid mobilizationfatty acid β-oxidationPXNPME311089https://doi.org/10.1534/genetics.116.193169