Related Experiment Videos
Cellular pattern of photosynthetic gene expression in developing maize leaves
J A Langdale1, B A Rothermel, T Nelson
1Department of Biology, Yale University, New Haven, Connecticut 06511.
Genes & Development
|January 1, 1988
Summary
Maize leaf development involves specialized cells for C4 photosynthesis. This study tracks key C4 gene expression, revealing early cell differentiation patterns and asynchronous development in normal and mutant maize leaves.
Area of Science:
- Plant Biology
- Molecular Biology
- Developmental Biology
Background:
- C4 plants like maize exhibit Kranz leaf anatomy with two distinct photosynthetic cell types: bundle sheath (BS) and mesophyll (M).
- This cellular dimorphism is crucial for partitioning C4 photosynthetic pathway enzymes into specific cell types.
- Previous research indicated C4 protein appearance coincides with Kranz anatomy formation.
Purpose of the Study:
- To investigate earlier events in BS and M cell development preceding morphological Kranz anatomy.
- To utilize cell-specific C4 mRNAs as markers for tracking BS and M cell differentiation in maize.
- To analyze the spatial and temporal patterns of C4 gene expression during leaf development in normal and mutant maize.
Main Methods:
- In situ hybridization was employed to monitor the accumulation of malic enzyme (ME), phosphoenolpyruvate carboxylase (PEPCase), and ribulose bisphosphate carboxylase (RuBPCase) mRNAs.
- A partial cDNA clone for maize ME was isolated to study ME mRNA expression.
- Developing leaves from both normal and argentia (ar) mutant maize seedlings were analyzed.
Main Results:
- All three C4 mRNAs (ME, PEPCase, RuBPCase) showed cell-specific accumulation patterns throughout development in both normal and ar maize.
- BS cell-specific mRNAs accumulated around developing veins prior to the morphological appearance of Kranz anatomy.
- Analysis of the ar mutant revealed delayed C4 mRNA appearance relative to Kranz anatomy, indicating BS and M cells develop in clusters and BS cells activate asynchronously.
Conclusions:
- The spatial and temporal patterns of C4 mRNA accumulation provide insights into the sequence of BS and M cell development.
- The argentia mutant data suggest a distinct developmental program for BS and M cell clustering and asynchronous activation.
- These findings contribute to understanding the models and mechanisms governing BS and M cell development in C4 plants.