A research team led by Professor Kang Xiangyang from Beijing Forestry University's College of Biological Sciences and Biotechnology has made significant progress in understanding the molecular regulation of chlorophyll biosynthesis in poplar. Their findings have been published in Plant, Cell & Environment (Q1, top-tier journal in biology). The study, titled "CCT39 Transcription Factor Promotes Chlorophyll Biosynthesis and Photosynthesis in Poplar", identifies the critical role of CCT39 Transcription Factor in regulating chlorophyll production and photosynthesis.

Chlorophyll serves as a crucial pigment in plants, essential for photosynthesis, growth, and development. The research team's previous study has shown that PpnCCT39 can increase leaf chlorophyll content and photosynthesis rate in poplar. However, the underlying molecular mechanisms remain unknown. In this study, researchers observed that overexpression of PpnCCT39 not only elevates chlorophyll content and photosynthesis, but also induces alterations in leaf morphology, basal diameter, and chloroplast structure. By performing RNA-seq on terminal buds and leaves at leaf positions 1, 3, 5, and 10, the team determined that PpnCCT39 predominantly exerts its effercts in young leaves. Chromatin Immunoprecipitation Sequencing (ChIP-seq) performed on PpnCCT39-overexpressing poplars identified 17 194 potential regulatory target genes. By integrating RNA-seq and ChIP-seq datasets along with validation assays for protein-DNA interactions, researchers determined that PpnCCT39 directly stimulated the transcription of three key genes involved in the chlorophyll biosynthesis and photosynthesis pathways: PagHO1, PagLIL3, and PagPYG7. Furthermore, protein interaction assays revealed that PpnCCT39 interacts with PagRD19 and PagATP2, localized in vesicles and mitochondria respectively, with these interactions occurring within chloroplasts. This study elucidates the molecular mechanism by which the PpnCCT39 transcription factor in poplar promotes chlorophyll biosynthesis and photosynthesis. It also highlights the critical role of PpnCCT39 in nucleocytoplasmic interactions. These findings underscore the significance of PpnCCT39 in regulating chlorophyll biosynthesis and enhancing photosynthesis through molecular design.

Chen Hao, a doctoral candidate at the College of Biological Sciences and Biotechnology, served as the first author of the paper. Professor Kang Xiangyang acted as the corresponding author. The research team also included significant contributions from assistant researcher Wu Wenqi of the Institute of Crop Science at the Chinese Academy of Agricultural Sciences, as well as lecturer Du Kang and Associate Professor Yang Jun of BFU.

This work was supported by the National Key R&D Program of China during the 14th Five-year Plan Period (2021YFD2200105).

Paper link: https://doi.org/10.1111/pce.15329

Written by Chen Hao
Translated and edited by Song He
Reviewed by Yu Yangyang