Recently, the crop metabolism regulation and nutrition biofortification team of the Biotechnology Research Institute has performed a cooperative research with the Institute of plant physiology and ecology in Shanghai and Ghent University in Belgium. By exploiting a specific photoaffinity probe in an affinity proteomics study , the folate interacting proteins in Arabidopsis thaliana were retrieved. It revealed that folates were closely related to plant carbon/nitrogen metabolism, and this sets a landmark towards understanding the role of folates in plant development. The research results were published in the journal of《the plant cell》.

Folates, a collective term for tetrahydrofolate (THF) and its derivatives, also known as vitamin B9, are essential for central metabolism. Defects in folate biosynthesis and metabolism have been shown to cause multiple aberrations in plant growth and development. But the molecular mechanism of action of folates remains ill-defined, and the folate interacting proteins in plants have been less identified.
In this study, 5-formyl-tetrahydrofolate (5-F-THF) was covalently coupled with diazirine-alkyne (Dayne) to synthesize the novel ‘5-F-THF-Dayne’. After confirming the bioactivity of this probe, it was used as a bait to fish for 5-F-THF-binding proteins (FFBPs) in Arabidopsis. A total of 51 FFBPs were identified, 30 interactions were independently validated with in vitro expressed proteins to bind 5-F-THF with high or low affinity. Interestingly, the interactors reveal associations beyond one-carbon metabolism, covering also connections to nitrogen metabolism, carbohydrate metabolism. Furtherly, the binding sites for 5-F-THF in two of the interactions, the folate biosynthetic enzyme DIHYDROFOLATE REDUCTASE-THYMIDYLATE SYNTHASE 1 (AtDHFR-TS1) and the nitrogen metabolism-associated glutamine synthetase 1;4 (AtGLN1;4), were determined and the effect of 5-F-THF binding on AtDHFR-TS1 and AtGLN1;4 enzyme activities was revealed. This study significantly expands our knowledge on fundamental folate biology and holds promise to facilitate further research on the action mechanism of folates in plants.

Dr. Weichao Li from Institute of plant physiology and ecology in Shanghai, Dr. Qiuju Liang from Biotechnology Research Institute of Chinese Academy of Agricultural Sciences and Dr. Ratnesh Chandra Mishra of Ghent University in Belgium are the co-first authors, Prof. Chunyi Zhang from Biotechnology Research Institute of Chinese Academy of Agricultural Sciences and Prof. Dominique Van Der Straeten from Ghent University in Belgium, are the correspondence authors. This research was supported by the National Natural Science Foundation of China and the Scientific and Technological Innovation Project of the Chinese Academy of Agricultural Sciences. This paper is dedicated to the memory of Prof. Youli Xiao, who passed away on January 30, 2020. Prof. Xiao and his team has successfully applied chemical proteomics technology in plants, which greatly promoted the research on the interaction of large and small molecules in plants.

Original link: https://doi.org/10.1093/plcell/koab198