Influence of TOR (Target of Rapamycin) pathway on starch metabolism in Arabidopsis thaliana

• Grant number: 15/04658-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2015
• Effective date (End): December 31, 2015
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Camila Caldana
• Grantee: Luís Guilherme Furlan de Abreu
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovações (Brasil). Campinas , SP, Brazil
• Associated research grant: 12/19561-0 - Regulation of plant growth by the Target of rapamycin (TOR) pathway, AP.BIOEN.JP

Abstract

Plant growth and development are maintained by a complex network controlled by both environmental cues (such as light and nutrient availability) and molecular signaling pathways. One of the master players in linking photosynthesis-driven nutrient status and energy sensor is the Target of Rapamycin (TOR) kinase. Arabidopsis plants with disruption of TOR levels displayed a decrease in photosynthesis and severe reprogramming of energy-, lipid- and carbon metabolism. Starch is one of major forms of carbohydrate storage and its accumulation was shown to be negatively correlated with plant growth. Arabidopsis transgenic lines exhibiting down-regulation of AtTOR expression displayed starch accumulation, whereas seedlings treated with the ATP-competitive inhibitor of the TOR complex (AZD8055) presented a higher starch content already after 12 horas of treatment. It is remain an open question whether the starch accumulation phenotype in the TOR transgenic lines is caused by activation of synthesis or inhibition of degradation. The aim of this work is to investigate the mechanism of starch regulation triggered by TOR using combination of different mutants involved in starch synthesis and degradation and the ATP-specific inhibitor AZD8055. It is expected that the results generated will allow the elucidation of the mode of action of TOR in the regulation of carbon allocation in plants, opening new perspectives for the conversion of photo-assimilates into biofuels.