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Alterations in chlorophyll a/b binding proteins in Solanaceae cybrids
E Babiychuk1, R Schantz, N Cherep
1Institute of Cell Biology and Genetic Engineering, Kiev, Ukraine.
Molecular & General Genetics : MGG
|December 20, 1995
Summary
Plant cybrids reveal that plastome-encoded factors influence chlorophyll a/b binding protein (CAB) biogenesis in the light harvesting complex II (LHCII). This suggests plastid factors may cause genetic incompatibility in plants.
Area of Science:
- Plant molecular biology
- Genetics
- Biochemistry
Background:
- The light harvesting complex II (LHCII) is crucial for photosynthesis.
- Understanding the biogenesis of LHCII components is essential for plant physiology.
Purpose of the Study:
- To investigate the role of plastome-encoded factors in the biogenesis of chlorophyll a/b binding proteins (CAB) in plant cybrids.
- To determine if genetic incompatibility between nuclear and plastid genomes affects protein processing.
Main Methods:
- Construction of plant cybrids by combining different nuclear and plastome genomes.
- Biochemical and immunological analyses of CAB polypeptides.
- Direct protein micro-sequencing of truncated CAB polypeptides.
Main Results:
- Cybrids exhibited altered biogenesis of CAB proteins, with reduced abundance of normal-sized polypeptides and appearance of additional, smaller polypeptides.
- Truncated 26 kDa CAB polypeptides in specific cybrids were identified as encoded by type 1 Lhcb genes, with N-terminal deletions.
- These truncated polypeptides were 11-12 amino acids shorter than expected.
Conclusions:
- Plastome-encoded factors likely play a critical role in the in vivo biogenesis of LHCII.
- Specific protein degradation and/or abnormal processing mediated by plastid factors may underlie compartmental genetic incompatibility in plants.