Regulation of ACC synthase in response to brassinosteroid

• Grant number: 15/25469-7
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: May 01, 2016
• End date: December 31, 2016
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal Investigator: Marcelo Menossi Teixeira
• Grantee: José Sérgio de Macedo Soares
• Supervisor: Joseph J. Kieber
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: University of North Carolina at Chapel Hill (UNC), United States
• Associated to the scholarship: 14/10003-0 - Cross-talk between brassinosteroid and ethylene in sugarcane ripening: regulation of ACC synthase via brassinosteroid, BP.PD

Abstract

Sugarcane (Saccharum hybrids) is a very efficient biomass producer and has the capacity to accumulate high concentrations of sucrose in the stem. Ethylene is a phytohormone that plays an important role in the regulation of growth and sucrose accumulation in sugarcane. The rate limiting step of ethylene biosynthesis is mediated by the enzyme 1-aminocyclopropane-1-carboxylase synthase (ACS). In several hormone biosynthesis and signaling pathways, protein turnover has emerged as a common regulatory element. These proteins may function as cross-talk points, interconnecting hormone signaling pathway with molecular mechanisms regulating various aspects of plant physiology. Brassinosteroid (BR) is a steroid hormone that functions as a master regulator of plant growth and belong to a group of factors influencing ethylene biosynthesis through the regulation of ACS protein stability. In this research project we will investigate the effects of brassinosteroid in ethylene biosynthesis via sugarcane ACS regulation. In our first results, etiolated rice wild-type seedlings showed an increase in ethylene production in the presence of brassinolide (BL). To identify which BR signaling component is involved in ethylene biosynthesis we will measure ethylene emission in rice loss-of-function BR signaling mutants. And to determine if ethylene production by BR is the result of an increase in ACSs stability we will use rice and sugarcane protoplasts to measure the stability of myc-epitope-tagged ACS under the control of the dexamethasone inducible promoter in the presence of BL. The elucidation of ACS regulation mechanism via brassinosteroid signaling will provide significant knowledge not only in sugarcane growth and ripening, but also for plant in general. (AU)