Mining Myb transcription factors related to wood development in Larix olgensis

Larix olgensis A.Henry is a fast-growing tree used for afforestation in northeastern China and has great ecological and economic value. For studying developmental genes in the xylem of this species, we investigated the Myb transcription factor family, one of the largest families of transcription factors in plants, which plays an important role in the regulation of lignification in plant secondary walls. By sequencing a L. olgensis cDNA library using the Illumina HiSeq2500 high-throughput sequencing platform, we obtained 58,683 unigene sequences, of which 16,554 unigenes were longer than 1000 bp, accounting for 28.2% of the total database. The alignment of these genes with the GO, COG, KEGG, Swiss-Prot and NR databases resulted in annotated 29,350 unigenes. We obtained a total of 1460 differentially expressed genes, of which 453 were upregulated and 1007 were downregulated at the two developmental stages analyzed. The gene annotations showed a wide range of biological functions and metabolic pathways. The 10 Myb transcription factors that were obtained from the differentially expressed genes were analyzed by real-time quantitative PCR (qRT-PCR). The results showed that four Myb transcription factors may be associated with xylem development in L. olgensis. Due to the large genome size of conifers, genomics research on these species has lagged behind that for other plant groups. Our data provide the basis for further studies on xylem development in L. olgensis.