Thioredoxin Redox Regulates ATPase Activity of Magnesium Chelatase CHLI Subunit and Modulates Redox-Mediated Signaling in Tetrapyrrole Biosynthesis and Homeostasis of Reactive Oxygen Species in Pea Plants

• DOI: 10.1104/pp.112.195446
• Publication Date: 2012-03-29T00:14:18Z
• Authors: Tao Luo; Tingting Fan; Yinan Liu; Maxi Rothbart; Jing Yu; Shuaixiang Zhou; Bernhard Grimm; Meizhong Luo
• Keywords: Adenosine Triphosphatases; Cell Nucleus; Chlorophyll; 0301 basic medicine; 0303 health sciences; Molecular Sequence Data; Agrobacterium; Lyases; Aminolevulinic Acid; Genes, Plant; Plants, Genetically Modified; Enzyme Activation; Chloroplast Thioredoxins; 03 medical and health sciences; Phenotype; Protein Interaction Mapping; Homeostasis; Gene Silencing; Photosynthesis; Reactive Oxygen Species; Oxidation-Reduction; Pisum sativum; Plant Proteins

Abstract The chloroplast thioredoxins (TRXs) function as messengers of redox signals from ferredoxin to target enzymes. In this work, we studied the regulatory impact pea (Pisum sativum) TRX-F on magnesium (Mg) chelatase CHLI subunit and enzymatic activation Mg in vitro vivo. vitro, reduced activated ATPase activity enhanced reconstituted three recombinant subunits CHLI, CHLD, CHLH combination with regulator protein GENOMES UNCOUPLED4 (GUN4). Yeast two-hybrid bimolecular fluorescence complementation assays demonstrated that physically interacts but not either other two or GUN4. vivo, virus-induced gene silencing (VIGS-TRX-F) plants did result an altered state CHLI. However, simultaneous TRX-M genes (VIGS-TRX-F/TRX-M) resulted partially fully oxidized VIGS-TRX-F/TRX-M a significant reduction 5-aminolevulinic acid synthesizing capacity well pigment content lower photosynthetic capacity. These results suggest that, can compensate for lack both TRXs act important regulators chelatase. Furthermore, expression also affects tetrapyrrole biosynthesis pathway leads accumulation reactive oxygen species, which may serve additional signal transcriptional regulation photosynthesis-associated nuclear genes.