Raphael Kiekens
Vrije Universiteit Brussel ,Belgium
Title: The role of the 4-HTHDPS gene family in symbiotic and abiotic stress responses in plants of the Fabaceae family
Biography
Biography: Raphael Kiekens
Abstract
As the world faces more challenges linked to food security and environmental preservation, the specific characteristics of legumes (Fabaceae) make them important candidates to reach sustainable agriculture. Apart from their high protein content, legumes are relatively rich in the amino acid lysine. Lysine is referred to as an ‘essential’ amino acid, because it cannot be synthesized by humans or monogastric animals and is considered to be the most limiting dietary component in food and feed. The biosynthesis of lysine is tightly regulated by 4-hydroxy-tetrahydrodipicolinate synthase (4-HTHDPS), our candidate gene (family) of interest. Recently the 4-HTHDPS gene family of the model legume plant Medicago truncatula was analyzed, which led to the discovery of novel, legume specific, 4-HTHDPS genes with multiple amino acid substitutions on positions previously shown to be involved in feedback inhibition and of residues important for catalytic activity, possibly affecting the enzymatic properties of these isoforms. Furthermore, these newly discovered isoforms seem to be specifically upregulated in roots colonized with mycorrhizal fungi or infected with pathogens, thus suggesting a role for these 4-HTHDPS genes in pathogenesis in legumes. By use of natural variation, publically available - and induced CRISPR/Cas9 mutants, we want to elucidate the functions and interplay of all 4-HTHDPS isoforms within the aspartate metabolic pathway together with its role in symbiosis with Rhizobia and (a)biotic stress responses in Fabaceae.