Proteome analysis of pollen in the K-type male sterility line 732A and its maintainer 732B in wheat (Triticum aestivum L.) by two-dimensional gel electrophoresis

Male sterility, especially cytoplasmic male sterility (CMS) where no functional pollen is produced, plays an important role in wheat breeding. Some specific proteins are related to male sterility in wheat, especially those present in pollen. To elucidate these sterility-related proteins, we applied two-dimensional gel electrophoresis (2-DE) to the proteomic analysis of pollen from a CMS line (732A) and its maintainer (732B) in wheat (Triticum aestivum L.), where trichloroacetic acid/acetone precipitation was used to extract pollen proteins from the wheat anthers. Analysis using PDQuest detected >350 reproducible protein spots on each 2-DE gel, where pI 4–7. In total, 41 spots were found to be differentially expressed, where 7/41 were identified by MALDI TOF/TOF–mass spectrometry analysis and protein database searching. The proteins comprised NADPH-producing dehydrogenase in the oxidative pentose phosphate pathway, cinnamyl alcohol dehydrogenase, cytosolic 3-phosphoglycerate kinase, caffeic acid O-methyltransferase, ascorbate peroxidase, glutamine synthetase isoform GS1a, and one unknown protein. In the uninucleate stage, all of the identified protein spots were downregulated in 732A, except the unknown protein, whereas there were no obvious differences in 732B. In the binucleate stage, the expression level of glutamine synthetase isoform GS1a did not differ between 732A and 732B, but caffeic acid O-methyltransferase was downregulated in 732A and the other five proteins were upregulated in 732A. These results suggest that male sterility in 732A is related to energy metabolism perturbation, active oxygen accumulation, programmed cell death, the pentose phosphate pathway, and glycolysis.