Functions and Remodelling of Plant Peroxisomes

Abstract

Peroxisomes are dynamic eukaryotic organelles that perform a wide range of important metabolic processes. In plants, the peroxisome is the sole organelle to carry out β‐oxidation of fatty acids, break down hydrogen peroxide, and performs several other functions required at different stages of plant development and under different conditions. The ability of this organelle to perform a range of functions depends on the time‐ and process‐dependent import of particular enzymes that enable biochemical reactions to take place inside peroxisomes. While it is important to recruit the right enzymes, it is also important to remove obsolete or damaged enzymes through the turnover of specific proteins. In some cases, degradation of the entire peroxisome is carried out by the process of autophagy, which helps to maintain quality control by removing damaged/dysfunctional/obsolete peroxisomes. Therefore, the diversification of plant peroxisomes for different cellular requirements is achieved through targeted turnover and import of specific enzymes. This article discusses the possible mechanisms and factors involved in functional remodelling of the plant peroxisome from the young seedling peroxisome to the leaf peroxisome. Functions of peroxisomes found in different developmental stages of the plant are also highlighted. Key Concepts Peroxisomes are single membrane‐bound eukaryotic organelles that perform a wide range of functions and display remarkable metabolic diversity. Peroxisomes do not contain any genetic information and therefore all peroxisomal proteins are imported post‐translationally from the cytosol. Peroxisomes are a major scavenger of hydrogen peroxide and plant peroxisomes are the sole site for β‐oxidation of fatty acids. Protein content of peroxisomes varies in a developmental and functional manner. In young seedlings post‐germination, peroxisomes house glyoxylate cycle enzymes that help to generate energy from oil reserves in the seed. In etiolated mature seedlings, peroxisomes are ‘remodelled’ to perform photorespiration. Peroxisome remodelling is achieved by removing glyoxylate cycle enzymes and importing photorespiration enzymes. Glyoxylate cycle enzymes are removed by turnover either inside or outside peroxisomes by proteases and/or by the turnover of obsolete peroxisomes through autophagy process.

Peroxisomes: versatile organelles with diverse roles in plants

“…SCPL20 is involved in b-oxidation and plant pathogen response (Floerl et al, 2012;Quan et al, 2013), and RDL1 plays a role in b-oxidation, seed viability and stress response (Quan et al, 2013). During oil seed germination, the glyoxylate cycle enzymes are replaced by photorespiration enzymes (Paudyal et al, 2017). Plant peroxisomal proteome varies to some extent in different developmental stages and tissue types.…”

“…Plant peroxisomal proteome varies to some extent in different developmental stages and tissue types. During oil seed germination, the glyoxylate cycle enzymes are replaced by photorespiration enzymes (Paudyal et al, 2017). This remodeling of the plant peroxisomal proteome most likely involves the simultaneous action of several processes, such as LON2-mediated degradation of the glyoxylate cycle enzymes and pexophagy-mediated degradation of the obsolete peroxisomes ( Fig.…”

Identification of Arabidopsis Protein Kinases That Harbor Functional Type 1 Peroxisomal Targeting Signals

“…Peroxisome biogenesis, functions ( Kao et al, 2018 ), remodelling ( Paudyal et al, 2017 ; Luo and Zhuang, 2018 ) and crosstalk with other organelles ( Oikawa et al, 2015 ; Thazar-Poulot et al, 2015 ; Jaipargas et al, 2016 ) is expected to be fine-tuned under varying cellular conditions through various post-translational modifications (PTMs) ( Sandalio et al, 2019 ). Yeast protein kinase and phosphatase mutants show a role for protein phosphorylation in peroxisome formation, size, fission, and pexophagy ( Saleem et al, 2008 ; Oeljeklaus et al, 2016 ).…”