Cloning and Expression Pattern Analysis of the ApNAP Gene in Asarina procumbens

Asarina procumbens, Scrophulariaceae, is a perennial vine and good ornamental plant for vertical greening in the garden. However, when the leaves of A.procumbens become dry and abscised after senescing, the bare tendrils greatly reduce its ornamental value. AtNAP is a NAC family transcription factor gene that plays a key role in regulating leaf senescence in Arabidopsis. In this study, ApNAP, a homologous gene of AtNAP, was cloned from A.procumbens senescent leaves by RT-PCR and RACE. Results showed that the ApNAP gene was located in the nucleus and had a total length of 1341 bp with an open reading frame of 936 bp, encoding 311 amino acids, of which the relative molecular weight was 35.21 kD and the isoelectric point was 9.13. The length of the genome was 1526 bp with two introns and three exons. Multiple sequence alignment indicated that the ApNAP gene was a NAC transcription factor. Phylogenetic analysis indicated that the ApNAP gene belonged to the NAP subfamily and shared highest similarity with AtNAM in Arabidopsis. The results of real-time qPCR showed that the expression level of ApNAP was increased under treatments induced by natural and dark-induced senescence, indicating that it was involved in the regulation of the leaf senescent process of A.procumbens. The isolation and cloning of ApNAP had an important value in delaying leaf senescence and improving the greening value of A.procumbens.