Cloning of C₄ PPDK Gene from Maize Inbred Lline B73 and the Effect of Low N on PPDK Expression

Key words: 
• maize /
• PPDK /
• low nitrogen /
• protein /
• expression

Abstract: The number of exons and introns of maize C₄ PPDK gene is uncertain in the existing references and the annotation was incorrect in the database of maize inbred line B73 whose genome has been sequenced. We successfully cloned the c DNA of C₄ PPDK gene from the leaves of the maize inbred line B73. The sequencing results indicated there were 19 exons and 18 introns in the PPDK of the maize line B73,which were different from those in the previous publication. We further characterized the function of C₄ PPDK and its response to the low nitrogen treatment. There is no dramatic phenotypic difference between the wild type and the heterozygous ppdk mutant under either high or low N condition. However,the homozygous mutant could not survive without PPDK gene. The western blotting indicated that PPDK was involved in the low N response since the low N induced the accumulation of PPDK protein. These results provided useful information for identification of the relationship between PPDK and N metabolism.