State Key Laboratory of Tree Genetics and Breeding , Research Institute of Subtropical Forestry, Chinese Academy of Forestry , Hangzhou 311400 , China.
Key Laboratory of Forest Genetics and Breeding , Research Institute of Subtropical Forestry, Chinese Academy of Forestry , Hangzhou 311400 , China.
J Agric Food Chem. 2019 Mar 6;67(9):2547-2562. doi: 10.1021/acs.jafc.8b03399. Epub 2019 Feb 21.
Camellia oleifera, as an important nonwood tree species for seed oil in China, has received enormous attention owing to its high unsaturated fatty acid contents benefited to human health. It is necessary to examine allelic diversity of key genes that are associated with oil production in C. oleifera cultivars with a large variation of fatty acid compositions. In this study, we performed the association analysis between four key genes (two CoSAD and two Cofad2) coding fatty acid desaturases and traits including oil content and fatty acid composition. We identified two single nucleotide insertion-deletion (InDel) and 362 single-nucleotide polymorphisms (SNPs) within the four candidate genes by sequencing an association population (216 accessions). Single-marker (or haplotype) and traits association tests were conducted by linkage disequilibrium (LD) approaches to detect significant marker-trait associations. Validation population (279 hybrid individuals from six full-sibs families) studies were performed to validate the function of allelic variations significantly associated. In all, 90 single marker-trait and one haplotype-trait associations were significant in association population, and these loci explained 1.87-17.93% proportion of the corresponding phenotypic variance. Further, six SNP marker-trait associations ( Q < 0.10) from Cofad2-A, CoSAD1, and CoSAD2 were successfully validated in the validation population. The SNP markers identified in this study can potentially be applied for future marker-assisted selection to improve oil content and quality in C. oleifera.
油茶是中国重要的木本油料树种，因其富含对人体健康有益的不饱和脂肪酸而备受关注。因此，有必要对脂肪酸组成差异较大的油茶品种中的关键基因进行等位基因多样性分析，这些基因与油脂产量有关。本研究通过对一个包含 216 个个体的关联群体进行测序，在四个候选基因（两个 CoSAD 和两个 Cofad2）中发现了两个单核苷酸插入/缺失（InDel）和 362 个单核苷酸多态性（SNP）。通过连锁不平衡（LD）方法，进行单标记（或单倍型）和性状关联测试，以检测显著的标记-性状关联。通过对来自六个全同胞家系的 279 个杂交个体的验证群体研究，对与等位基因变异显著相关的性状进行了功能验证。在关联群体中，共有 90 个单标记-性状和 1 个单倍型-性状关联达到显著水平，这些位点解释了相应表型变异的 1.87%-17.93%。此外，在验证群体中，从 Cofad2-A、CoSAD1 和 CoSAD2 中成功验证了 6 个 SNP 标记-性状关联（Q<0.10）。本研究中鉴定的 SNP 标记可用于未来的标记辅助选择，以提高油茶的含油率和品质。
