In order to study the relationship between of pepper cytoplasmic male sterility and energy metabolism,we cloned pepper glucose-6-phosphate dehydrogenase gene (CaG6PDH) based on the G6PDH homologous sequences of the related species tomato by the electronic cloning in this research.Real-time quantitative-PCR was used to analyze the gene expression levels in the different stages of flower development in the cytoplasmic male sterility line (9704A) and its maintainer line (9704B),and different tissues(stem,leaf,flower,pericarp,placenta and seed) in the 9704B.The results showed that there was no difference of cDNA sequences between the CaG6PDH in the 9704A and the 9704B.Sequence prediction showed that the 1 533 bp cDNA sequences represent 1 single gene,which encodes 510 amino acids.CaG6PDH gene has a different expression in the different tissues in the 9704B,the highest in the placenta and the lowest in the stem.CaG6PDH gene expression in 9704A was higher than that in 9704B during the different stages of flower development,especially in the uninucleate microspore stage and mature pollen stage.The abnormal expression level of CaG6PDH in the 9704A disturbed the balance of energy metabolism and interfered the development of microspore,then resulted male sterility in the pepper.