Cloning and Expression Analysis of <i>PeDIR19</i> Gene in Poplar

Abstract

Dirigent ( DIR ) gene plays an important role in the formation of lignin and lignans by controlling the stereoselective coupling of pineperin alcohol monomers in plants during the polymerization of lignin and lignans. In this study, we take the ‘Nanlin 895’ ( Populus deltoides × P. euramericana  cv ‘Nanlin 895’) as the material, and clone the PeDIR19  gene. PeDIR19 , the whole length of 588 bp, has a length of 555 bp in ORF region and has only a length of 33 bp intron in the middle. PeDIR19 protein codes 185 amino acids and is a hydrophobic protein. It has four conservative motifs and has a highly conservative structural functional domain between 50 bp ~ 142 bp. PeDIR19  gene was found to have the highest homology with Populus trichocarpa   PtDIR19 ( Potri.001G009100 ), with only four bases differences. By phylogenetic analysis, PeDIR19  gene belongs to DIR -B/D subfamily. Through tissue specific expression analysis of ‘Nanlin 895’ with different growth stages, it was found that PeDIR19  gene expression level was the highest in the root during the tissue culture seedlings and in the stem during the pot seedlings. PeDIR19  gene had a strong response after 1 d under the induction of Yangpan Erbaojun ( Marssonina brunnea ). Under the induction of salicylic acid, methyl jasmonate and abscisic acid stress, PeDIR19  gene can strongly respond to the stress of methyl jasmonate and abscisic acid and weakly respond to the salicylic acid stress. This study provides a solid foundation for further study on the function identification of DIR  gene in the biosynthetic pathway of plant resistance.