Biligen-Gaowa Zhao1,2, Guo Li1,2, Yue-Feng Wang1,2, Zhen Yan1,2, Feng-Qin Dong3, Ying-Chang Mei1,2, Wei Zeng4, Meng-Zhu Lu4, Hong-Bin Li5, Qing Chao6,7, Bai-Chen Wang8,9. 1. Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. 2. University of Chinese Academy of Sciences, Beijing, 100049, China. 3. The Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China. 4. Sino-Australia Plant Cell Wall Research Centre, State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A and F University, Hangzhou, 311300, China. 5. Key Laboratory of Xinjiang Phytomedicine Resource and Utilization of Ministry of Education, College of Life Sciences, Shihezi University, Shihezi, 832003, China. 6. Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. chaoqing@ibcas.ac.cn. 7. University of Chinese Academy of Sciences, Beijing, 100049, China. chaoqing@ibcas.ac.cn. 8. Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. wangbc@ibcas.ac.cn. 9. University of Chinese Academy of Sciences, Beijing, 100049, China. wangbc@ibcas.ac.cn.
Abstract
MAIN CONCLUSION: PdeHCA2 regulates the transition from primary to secondary growth, plant architecture, and affects photosynthesis by targeting PdeBRC1 and controlling the anatomy of the mesophyll, and intercellular space, respectively. Branching, secondary growth, and photosynthesis are vital developmental processes of woody plants that determine plant architecture and timber yield. However, the mechanisms underlying these processes are unknown. Here, we report that the Populus transcription factor High Cambium Activity 2 (PdeHCA2) plays a role in the transition from primary to secondary growth, vascular development, and branching. In Populus, PdeHCA2 is expressed in undifferentiated provascular cells during primary growth, in phloem cells during secondary growth, and in leaf veins, which is different from the expression pattern of its homolog in Arabidopsis. Overexpression of PdeHCA2 has pleiotropic effects on shoot and leaf development; overexpression lines showed delayed growth of shoots and leaves, reduced photosynthesis, and abnormal shoot branching. In addition, auxin-, cytokinin-, and photosynthesis-related genes were differentially regulated in these lines. Electrophoretic mobility shift assays and transcriptome analysis indicated that PdeHCA2 directly up-regulates the expression of BRANCHED1 and the MADS-box gene PdeAGL9, which regulate plant architecture, by binding to cis-elements in the promoters of these genes. Taken together, our findings suggest that HCA2 regulates several processes in woody plants including vascular development, photosynthesis, and branching by affecting the proliferation and differentiation of parenchyma cells.
MAIN CONCLUSION: PdeHCA2 regulates the transition from primary to secondary growth, plant architecture, and affects photosynthesis by targeting PdeBRC1 and controlling the anatomy of the mesophyll, and intercellular space, respectively. Branching, secondary growth, and photosynthesis are vital developmental processes of woody plants that determine plant architecture and timber yield. However, the mechanisms underlying these processes are unknown. Here, we report that the Populus transcription factor High Cambium Activity 2 (PdeHCA2) plays a role in the transition from primary to secondary growth, vascular development, and branching. In Populus, PdeHCA2 is expressed in undifferentiated provascular cells during primary growth, in phloem cells during secondary growth, and in leaf veins, which is different from the expression pattern of its homolog in Arabidopsis. Overexpression of PdeHCA2 has pleiotropic effects on shoot and leaf development; overexpression lines showed delayed growth of shoots and leaves, reduced photosynthesis, and abnormal shoot branching. In addition, auxin-, cytokinin-, and photosynthesis-related genes were differentially regulated in these lines. Electrophoretic mobility shift assays and transcriptome analysis indicated that PdeHCA2 directly up-regulates the expression of BRANCHED1 and the MADS-box gene PdeAGL9, which regulate plant architecture, by binding to cis-elements in the promoters of these genes. Taken together, our findings suggest that HCA2 regulates several processes in woody plants including vascular development, photosynthesis, and branching by affecting the proliferation and differentiation of parenchyma cells.
Authors: Kyoko Baba; Anna Karlberg; Julien Schmidt; Jarmo Schrader; Torgeir R Hvidsten; Laszlo Bako; Rishikesh P Bhalerao Journal: Proc Natl Acad Sci U S A Date: 2011-02-02 Impact factor: 11.205
Authors: Anthony Bishopp; Hanna Help; Sedeer El-Showk; Dolf Weijers; Ben Scheres; Jiří Friml; Eva Benková; Ari Pekka Mähönen; Ykä Helariutta Journal: Curr Biol Date: 2011-05-27 Impact factor: 10.834
Authors: Francois F Barbier; Elizabeth A Dun; Stephanie C Kerr; Tinashe G Chabikwa; Christine A Beveridge Journal: Trends Plant Sci Date: 2019-03 Impact factor: 18.313
Authors: Laura E Dixon; Julian R Greenwood; Stefano Bencivenga; Peng Zhang; James Cockram; Gregory Mellers; Kerrie Ramm; Colin Cavanagh; Steve M Swain; Scott A Boden Journal: Plant Cell Date: 2018-02-14 Impact factor: 11.277