火炬松生长和松脂性状相关候选基因的单核苷酸多样性分析

Analysis of single nucleotide polymorphisms within candidate genes involved in growth and resin biosynthesis of loblolly pine

【目的】对火炬松Pinus taeda生长和松脂产量相关功能基因单核苷酸多态性(Single nucleotide polymorphism,SNP)位点进行筛选与分析,为分子标记辅助育种提供技术基础。【方法】利用生物信息学对火炬松c DNA文库进行整理、比对、剪接、注释,挑选出与生长素、赤霉素、细胞分裂素及蒎烯合成相关的非重复序列基因(Unigene)作为候选基因片段,利用MEGA5.0和Dna SP4.0软件对火炬松36个单株的8个候选基因片段进行序列比对和分析。【结果】所测序列总长为5 177 bp,检测到184个SNP位点,平均36.9 bp的基因序列中出现1个SNP位点,其中123个为非同义突变、61个为同义突变SNP位点。核苷酸多态性πa和θw分别为0.020和0.016。对8个候选基因片段内SNP位点进行的连锁不平衡分析显示,随着核苷酸序列长度的延伸,SNP位点的连锁不平衡在基因内部迅速衰退(R2≤0.2)。【结论】在火炬松中,基于候选基因内SNP位点间的连锁不平衡作图是可行的。

【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 c DNA library using bioinformatics.The sequences of eight candidate genes from 36 loblolly pine individuals were aligned and compared using MEGA5. 0 and Dna SP4. 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 diversityfor sequenced regions represented by πaand θwwere 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.