Characterization of maize leaf pyruvate orthophosphate dikinase using high throughput sequencing
Yuling Zhang1, Rita Giuliani2, Youjun Zhang3
1State Key Laboratory of Crop Biology, College of Agronomic Sciences, Shandong Agricultural University, Tai'an, 271018, China.
Journal of Integrative Plant Biology
|April 18, 2018
Summary
Genetic analysis of pyruvate orthophosphate dikinase (PPDK) in maize reveals its essential role in C4 photosynthesis. Loss-of-function mutants are seedling lethal, impacting CO2 assimilation and altering sugar metabolism.
Area of Science:
- Plant Biology
- Biochemistry
- Genetics
Background:
- Pyruvate orthophosphate dikinase (PPDK) is crucial for C4 photosynthesis, regenerating phosphoenolpyruvate in the carbon shuttle.
- While PPDK's biochemical role in maize is known, genetic analyses have been lacking.
Purpose of the Study:
- To conduct a genetic analysis of PPDK in maize.
- To investigate the transcriptional and metabolic consequences of PPDK deficiency.
Main Methods:
- Utilized maize transposable elements (Mutator and Ds) to create PPDK mutant alleles.
- Employed RNA-sequencing (RNA-seq) and Gas Chromatography-Mass Spectrometry (GC-MS) for analysis.
Main Results:
- Loss-of-function PPDK mutants exhibited seedling lethality and severely impaired CO2 assimilation, confirming the essentiality of C4 photosynthesis in maize.
- Downregulation of C4 cycle, Calvin cycle, and photochemistry gene expression was observed in mutants.
- Kranz anatomy remained unaffected, but sugar metabolism and nitrogen utilization were altered.
- Transcriptome profiling revealed genotype-by-light intensity interactions.
Conclusions:
- PPDK is indispensable for maize C4 photosynthesis and seedling survival.
- PPDK deficiency profoundly impacts C4 and Calvin cycle gene expression and alters fundamental metabolic pathways.
- The study highlights the intricate regulation of C4 photosynthesis and its interaction with environmental factors.
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