Genetic regulation of metabolic and physiological traits in Arabidopsis

CM FUSARI

Congreso; Reunión Conjunta SAIB-SAMIGE 2020; 2020

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular - Sociedad Argentina de Microbiología General

Understanding the highly coordinate regulation of plant metabolism components, is key to identify genetic factors involved in growth, metabolism responses to stress and, ultimately, reproduction and yield. Whilst earlier studies had reported the mapping of QTL for metabolite levels, we have achieved the first large scale study to identify QTL for enzyme activities. We were able to distinguish between two kinds of genetic polymorphisms that influence enzyme activity. First, changes in genes that encode for enzymes (structural genes or cis-QTL). Second, changes in genes that are responsible for regulatory processes such as the production, transport and stability of the enzymes (regulatory genes or trans-QTL). We demonstrated that cis- and trans-QTL contribute to genetic variability in enzyme activity, with cis-QTL being very strong for a small number of enzymes, but trans-QTL more common. Mutation on cis-QTL show little or no impairment of vegetative growth, but did exhibit silique and flower abortion phenotypes, suggesting that seed set is especially sensitive to minor lesions in metabolism that have little effect at other stages in the plant’s life history. In addition, we identified genes acting as regulatory hubs, being involved in the coordinate regulation of several metabolic components at once. One of them, ACD6, associated with 10 metabolic traits, is a well-characterized protein involved in defence responses and hybrid necrosis in Arabidopsis. This points to a close interdependence between metabolism and pathogen defence. Further findings and perspectives from this study and recent results on lipid-metabolism regulation under stress will be discussed.