Abstract
Cytochrome P450 monooxygenases (CYPs) are a group of redox proteins that catalyze various oxidative reactions in plant secondary metabolism. To explore the function of the CYP71 gene in Ginkgo biloba under biotic and abiotic stresses, a full-length CYP gene, designated GbCYP71, was first isolated and characterized from leaves of G. biloba. It contained a 1512-bp open reading frame (ORF) encoding 503 amino-acid-deduced polypeptide whose theoretical molecular weight was 56.9 kDa. The genomic DNA sequence of GbCYP71 contained two exons and one intron. The cDNA of GbCYP71 was subcloned in a pET-32a vector and then transformed into E. coli strain BL21 (DE3). A protein with a molecular weight of 76.4 kDa was subsequently identified and found to be consistent with the above theoretical value. Transient expression analysis revealed that the GbCYP71 protein may be located in the G. biloba cell cytoplasm. GbCYP71 was expressed in almost all ginkgo tissues, including leaves, stamens, gynoecia, stems and, preferentially, roots. Expression-profiling analyses revealed that GbCYP71 can be induced by salinity stress and phytohormone signals, including salicylic acid, abscisic acid, methyl jasmonate and ethephon, but is repressed by heat and cold stresses. These results indicate that GbCYP71 mainly functions in responding to biotic and abiotic stresses.
Highlights
Cytochrome P450 monooxygenases (CYPs) form the largest enzyme family and present in various tissues (Werck-Reichhart et al, 2000) in higher-order plants
The full-length cDNA sequence of the GbCYP71 gene was obtained from G. biloba
A 1630-bp genomic DNA sequence of the GbCYP71 gene was amplified by a pair of specific primers derived from the cDNA sequence containing the start and stop codon region
Summary
Cytochrome P450 monooxygenases (CYPs) form the largest enzyme family and present in various tissues (Werck-Reichhart et al, 2000) in higher-order plants. The CYPs are a group of redox proteins that catalyze the oxidation steps of various substrates using oxygen and NAD(P)H (Guttikonda et al, 2010; Isin and Guengerich, 2007). Plant CYPs have been shown to participate in many metabolic pathways, especially those related to plant secondary metabolism, which mainly involves the synthesis of endogenous compounds, such as structural macromolecules, pigments, and defense compounds; the synthesis or catabolism of all types of hormones or signaling molecules; and the metabolism of xenobiotics (Morant et al, 2003; Werck-Reichhart et al, 2002). The ability of CYPs to catalyze such diverse reactions in plants contributes greatly to understanding the challenge posed by abiotic stresses and pathogens in nature
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
