MAPK role in ethylene biosynthesis in Arabidopsis thaliana.

Sofija Semeniuk,Institute of Biotechnology, Vilnius, Lithuania

Sofija Semeniuk, Kotryna Kvederaviciute, Alois Schweighofer, and Irute Meskiene

Mitogen-activated kinases (MAPK) are among the most common signaling molecules in plants. In Arabidopsis thaliana their functions involve controlling cell proliferation and differentiation, as well as defense responses. Ethylene is a plant hormone, which regulates the processes involved in plant development and defense. Ethylene is produced in plants during wounding, such as leaf cutting or treatment with pathogens. Arabidopsis MAPK MPK6 is known to be responsible for phosphorylation and stabilization of ethylene biosynthesis enzyme ACC (1-aminocyclopropane-1-carboxylate) synthase (ACS) which is reaction rate controlling protein. In plants ethylene is synthesized from methionine. Three enzymes are involved in the biosynthesis process - ACS, ACC N-malonyl transferase and ACO (ACC oxidase). First, ACS converts S-adenosyl-L-methionine into ACC acid (1-aminocyclopropane-1-carboxylic acid). Next, either ACC N-malonyl transferase converts ACC acid into MACC (1-(malonylamino)cyclopropane-1-carboxylic acid) or with the help of ACO ethylene is produced out of it. In this research, we will analyze quantity of ethylene, ACC and MACC produced in MPK6 knock-out plants compared to the wild-type Arabidopsis as well as the activity of ACO enzyme. The elaboration of the methods will help to study other MAPK and MAPK phosphatase mutants and the received results will give us improved understanding of the role of MPK6 in ethylene production that could be later applied to agricultural plants for better understanding of the role of MAPK signaling in crop maturation, ripening and aging.