Cloning and molecular evolution of 9-cis-epoxycarotenoid dioxygenase gene (NCED3) in six species of Glycyrrhiza L

Abstract

Objective: To understand the evolutionary relationship of NCED3 in Glycyrrhiza L. and find genetic evidence of its local adaptation. Meanwhile, lay the foundation for relieving the demand and subsequent starvation of Glycyrrhiza resources. Methods: NCED3 were isolated from six species of Glycyrrhiza L. by rapid amplification of cDNA ends and a homology cloning strategy. The basic properties and evolutionary relationships of NCED3 were analyzed by bioinformatics. Results: Six NCED3 genes formed two clusters; they were under purifying selection and were highly conserved in evolution (Ka/Ks≤). There was very little functional divergence among the NCED3s (Alpha value 0.071). The contents of ABA in the six species were divided into two groups. Conclusion: This study provides the first analysis of the evolution of NCED3s in six species of Glycyrrhiza. Six NCED3 genes were slow evolutionary rates in six NCED3s. Different genetic relationships to Glycyrrhiza adapted to various environments. The changes in ABA content were consistent with the evolution of NCED3. Whether there are direct relationships between NCED3 and environmental adaptation, the answer is uncertain, and we hope to show more positive results in the further study of NCED3 in Glycyrrhiza L.

Keywords

• Glycyrrhiza
• NCED3
• Evolution
• Abscisic acid