The two major degradation systems work independently to support the growth strategy of plants

July 13, 2020

An argument concerning chloroplasts degradation has come to an end

The international joint research group with members from RIKEN CSRS, the University of Oxford, the University of Arizona, and Tohoku University has found that the two major intracellular degradation systems, namely "autophagy" and "ubiquitin-proteasome system," work independent of each other in plants to support the metabolism in vivo.

Autophagy and ubiquitin-proteasome are systems that breakdown intracellular components, in a wide range of living organisms, both animals and plants. It has been reported that the two systems work in many organisms, sometimes independently and sometimes by directly exchanging information, to break down waste products and recycle nutrients within the cells.

The international joint research group aimed to come up with a clear conclusion concerning the relationship between the two major degradation systems in plant leaves, which had been a subject of international discussion. Gene deletion variants and mutants were constructed using the model plant Arabidopsis thaliana to evaluate their growth and stress resistance. It was found that the two degradation systems work independent of each other to support the plant’s nutritional metabolism. When both systems fail together, active oxygen accumulates in excess causing leaves to die prematurely, and abnormalities occur even in the formation of seeds.

The results of this research have partially revealed the sophisticated internal nutrient recycling system of plants, and may contribute to designing crops that can maintain sufficient yield and quality while reducing the load on the environment by requiring less fertilizer.

Original article
Plant Physiology doi:10.1104/pp.20.00237
Y. Kikuchi, S. Nakamura, J. D. Woodson, H. Ishida, Q. Ling, J. Hidema, R. P. Jarvis, S. Hagihara, M. Izumi,
"Chloroplast autophagy and ubiquitination combine to manage oxidative damage and starvation responses".
Masanori Izumi; Research Scientist
Shinya Hagihara; Team Leader
Sakuya Nakamura; Visiting Researcher
Molecular Bioregulation Research Team