Expression Pattern Analysis of Larch IWRKY/I in Response to Abiotic Stress

Larix olgensis is one of the most common tree species in Northeast China; it has the advantages of fast growth and good wood properties. In order to accelerate larch molecular breeding and to provide good candidate genes for larch improvement, based on the existing transcriptome data of Larix olgensis, four WRKY family genes with complete CD regions were obtained by BLAST comparison on the NCBI website. The results of bioinformatics analysis and gene expression after abiotic stress showed that there were some differences in the expression of WRKY1, WRKY2, WRKY3 and WRKY4 in roots, stems and leaves under each treatment. Under the treatment of a 40% PEG[sub.6000] solution (polyethylene glycol), the expression of WRKY2 was significantly up-regulated in each time period and WRKY1, WRKY3 and WRKY4 were down-regulated in varying degrees compared with the control group, indicating that they were involved in the response to drought stress. Under the treatment of the 0.2mol/L NaCl solution, the expression of WRKY2 was up-regulated in roots, stems and leaves. The expression amount and the expression trend of the other three genes were different in roots, stems and leaves under different treatment durations, indicating that they were also involved in a salt-stress response. Under the treatment of the 0.1 mol/L NaHCO[sub.3] solution, the expression of WRKY4 was significantly down-regulated in all time periods, while WRKY2 was significantly up-regulated. The other two genes were regulated to a certain extent, indicating that they also had a physiological response under alkaline conditions. These results lay a foundation for the study of gene function of these four WRKY transcription factors.