Abstract:
Objective Single nucleotide polymorphisms (SNPs) within candidate genes involved in growth and resin biosynthesis of loblolly pine, Pinus taeda, were screened and analyzed, preparing technical basis for later marker-assisted breeding.
Method The candidate unigenes related to auxin, gibberellins, cytokinins or pinene synthesis were selected from loblolly pine cDNA library using bioinformatics. The sequences of eight candidate genes from 36 loblolly pine individuals were aligned and compared using MEGA5.0 and DnaSP4.0 softwares.
Result The total length of measured sequences was 5 177 bp. There were 184 SNPs to be detected, and in average there was one SNP site in every 36.9 bp sequence. Among them, 123 were nonsynonymous SNPs and 61 were silent SNPs. The levels of nucleotide diversity for sequenced regions represented by πa and θw were 0.020 and 0.016, respectively. The linkage disequilibrium(LD) of SNPs in the eight candidate genes declined rapidly (R2≤0.2) with the nucleotide sequences increased in length.
Conclusion LD mapping of SNPs in the five candidate genes are useful for loblolly pine breeding.