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Characterization of maize leaf pyruvate orthophosphate dikinase using high throughput sequencing
Author(s) -
Zhang Yuling,
Giuliani Rita,
Zhang Youjun,
Zhang Yang,
Araujo Wagner Luiz,
Wang Baichen,
Liu Peng,
Sun Qi,
Cousins Asaph,
Edwards Gerald,
Fernie Alisdair,
Brutnell Thomas P.,
Li Pinghua
Publication year - 2018
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/jipb.12656
Subject(s) - mutant , photosynthesis , phosphoenolpyruvate carboxylase , phosphoenolpyruvate carboxykinase , biology , c4 photosynthesis , biochemistry , metabolic pathway , enzyme , metabolism , gene , microbiology and biotechnology
In C 4 photosynthesis, pyruvate orthophosphate dikinase (PPDK) catalyzes the regeneration of phosphoenolpyruvate in the carbon shuttle pathway. Although the biochemical function of PPDK in maize is well characterized, a genetic analysis of PPDK has not been reported. In this study, we use the maize transposable elements Mutator and Ds to generate multiple mutant alleles of PPDK. Loss‐of‐function mutants are seedling lethal, even when plants were grown under 2% CO 2 , and they show very low capacity for CO 2 assimilation, indicating C 4 photosynthesis is essential in maize. Using RNA‐seq and GC‐MS technologies, we examined the transcriptional and metabolic responses to a deficiency in PPDK activity. These results indicate loss of PPDK results in downregulation of gene expression of enzymes of the C 4 cycle, the Calvin cycle, and components of photochemistry. Furthermore, the loss of PPDK did not change Kranz anatomy, indicating that this metabolic defect in the C 4 cycle did not impinge on the morphological differentiation of C 4 characters. However, sugar metabolism and nitrogen utilization were altered in the mutants. An interaction between light intensity and genotype was also detected from transcriptome profiling, suggesting altered transcriptional and metabolic responses to environmental and endogenous signals in the PPDK mutants.