Genome-Wide Characterization of Dirigent Proteins in Populus: Gene Expression Variation and Expression Pattern in Response to Marssonina brunnea and Phytohormones

Marssonina brunnea causes a major disease that limits poplar growth. Lignin and lignan play essential roles in protecting plants from various biological stresses. Dirigent (DIR) proteins are thought to control the stereoselective coupling of coniferyl alcohol formation lignin. DIR family members have been well studied several plant species, but no previous detailed genome-wide analysis has carried out forest trees, such as poplar. We identified 40 PtDIR genes Populus trichocarpa classified them into three subgroups (DIR-a, DIR-b/d, DIR-e) based on phylogenetic analyses. These distributed 11 chromosomes, 80% PtDIRs (32/40) intronless. The cis-element inferred possess many types abiotic stress-response cis-elements. also analyzed intra- inter-specific collinearity, which provided deep insights evolutionary characteristics genes. Analyses protein tertiary structure critical amino acid residues showed PtDIR7–10 PtDIR13–16, belong DIR-a subfamily, might be involved regio- stereo-selectivity bimolecular phenoxy radical poplars. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) revealed different expression patterns for P. PeDIR ‘Nanlin 895’ tissues. Additionally, we responses PeDIRs M. phytohormone treatments (abscisic acid, salicylic methyl jasmonate, ethylene) 895’. results at least 18 responded strongly brunnea, these significant phytohormones. suggest defense response against this study will provide fundamental future research