Genome wide identification and bioinformatic analysis of peroxisomal Small Thioesterase (ST) gene family in plant.

Peroxisomes, as essential eukaryotic organelles, are known to be involved in many oxidative metabolic processes including β-oxidative biosynthesis and/or metabolism of plant hormones and their substrates that are less or not known. The small thioesterase (ST) gene family encodes enzymes, called thioesterases that are notably involved in β-oxidative benzoic acid metabolism, as well as the biosynthesis of aromatic compounds and phylloquinone. To delve deeper into the role of these proteins in plant peroxisomes, we conducted an in-silico analysis to identify peroxisomal ST genes in Arabidopsis, focusing on identifying peroxisome-targeting signal peptide. In Arabidopsis, out of seven ST genes, three of them were experimentally verified as peroxisomal for the first time by confirming their sub-cellular localization. Phylogenetic studies revealed that peroxisomal ST genes are present in various plant species, underlining their functional conservation in peroxisomal metabolism. Insights into known peroxisomal STs in other species also aided in predicting the functions of Arabidopsis ST proteins within the same subgroup. Structural modeling indicates that Arabidopsis ST proteins possess a hotdog fold domain, a structural motif essential for thioesterase activity. In silico gene expression profiling showed that several ST genes are strongly expressed during the development of siliques, pods, and seeds, suggesting a role in these processes. This evidence supports the identification of a novel peroxisomal ST subfamily, prompting further investigation into their functions in Arabidopsis peroxisomes. This study provides a basis for further exploration of STs' roles in plant peroxisomal biology and their contributions to the redox regulation of peroxisome functions.