Title : Investigation of the aromatic amino acids branch pathway in the marine diatom Phaeodactylum tricornutum.
Abstract:
Aromatic amino acids (AAAs), including phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp), are essential building blocks for proteins and participate in various physiological processes in all living organisms. The biosynthesis of AAA in plants serves a multifaceted purpose, as they are precursors for a diverse group of specialized metabolites (e.g., alkaloids, flavonoids, lignins) that have a profound impact on growth, development, reproduction, and defense against biotic and abiotic stresses. In addition, AAAs are of particular interest due to their potential roles as precursors in the synthesis of many industrially important products.
Diatoms are a diverse group of microalgae known for their ability to fix carbon dioxide and produce significant amounts of biomass. Phaeodactylum tricornutum is a diatom that can be genetically engineered successfully and is particularly appealing due to its small genome size, quick generation time, and ease of genetic manipulation. Therefore, P. tricornutum is a promising candidate for metabolic engineering and the production of pharmaceutically relevant metabolites, often derived from AAAs, for the development of an economically viable bio-based process. For this reason, we aim to characterize and genetically engineer the AAAs pathway in this diatom. We have identified two putative P. tricornutum chorismate mutases (CM), one of the enzymes involved in the AAA pathway. The coding sequence was amplified from cDNA, cloned under the constitutive promoter 40SRPS8, and fused to the yellow fluorescent protein gene in both C and N terminal to analyze its production, localization and enzymatic activity in P. tricornutum. Meanwhile, we are predicting the structural model of PtCM enzymes, to target the allosteric sites that are negatively regulated by Phe and Tyr and activated by Trp. Our perspective could provide new insights in P. tricornutum AAAs pathways to develop further tools in this marine microalgae.
