Plant protein regulator provides insight into crop growth and protection

25 September 2018

Chinese University of Hong Kong cell and molecular biologist Professor Liwen Jiang (Croucher Senior Research Fellowship 2015 and 2009) has discovered a protein regulator in plant seedling development and pathogen defence that offers new insight for improving crop quality.

Jiang and his team have identified a negative regulator involved in the biogenesis of plants and their membrane protein vacuolar transport systems.

Plant development, defence, and many physiological processes rely on the transport machinery, ESCRT, to control the homeostasis of membrane proteins. Not only is this essential for the destruction of non-functional or misfolded proteins, but it also ensures proper cell signalling and facilitates interactions with the environment.

The importance of the ESCRT machinery in proteostasis is well established. However, the regulators that control the machinery’s function remain unclear.

Using a combination of genetic suppressor screening and cellular and biochemical characterisation approaches the team’s findings revealed that the BRAF protein regulates FREE1, an essential component in seedling development and pathogen defence in crops that they had previously discovered. The BRAF protein regulates more FREE1 when there are more plasma membrane (PM) proteins waiting for degradation. The latest study was published in Nature Communications in September 2018.

Jiang said that the discovery provided a deeper understanding of the molecular mechanism of plant multivesicular body biogenesis and a novel molecular basis for crop improvement. “Since ESCRT machinery controls the homeostasis of the many PM-localised hormone receptors, and the regulator BRAF is also conserved in the plant kingdom, for example in rice, maize and soybean, [this] further research on the molecular mechanism of plant BRAF provides new insight into how to improve crop quality to overcome a stress environment or pathogen infection, which have become serious problems in agriculture.”

Professor Bo Liu, of University of California, Davis, commented: “The discovery marks another breakthrough by Professor Jiang’s research team after their earlier discovery of the novel FREE1 protein, which plays an essential role in the biogenesis of multivesicular bodies or prevacuolar compartments in plant cells. It has advanced our knowledge on the regulatory mechanism underlying endosomal sorting, and will guide future studies on the homeostasis of membrane proteins that is of great significance in understanding plant growth and form.”

Professor Liwen Jiang is a Professor in the Department of Biology and Director of the Centre for Cell and Developmental Biology at the Chinese University of Hong Kong. Professor Jiang’s research focuses on understanding the molecular mechanisms of protein trafficking and organelle biogenesis in plant secretory and endocytic pathways as well as their applications in plant biotechnology.

To view Professor Jiang's Croucher profile, please click here