利用全基因體關聯性分析解析燕麥幼苗生長勢的遺傳結構

燕麥是全球第七大穀類作物，同時也是熱帶及亞熱帶地區的重要芻料作物。耕作方式屬粗放的芻料作物，為抵抗早期雜草，幼苗生長勢是重要的農藝性狀，同時也影響後期的芻料產量，但在過去並無對燕麥相關性狀遺傳因子的研究，因此本研究以來自全球重點燕麥育種計畫的650個優良燕麥品系 (CORE, Collaborative Oat Research Enterprise) 及來自美國農業部國家小穀物種源資源庫的378個燕麥地方種 (NSGC, USDA National Small Grains Collection)，共兩個族群1,028個種原作為研究材料，利用全基因體關聯性分析探討燕麥幼苗生長勢的遺傳結構。除了傳統的各時間點橫斷研究之外，同時也使用數學模型估計燕麥幼苗的生長動態。我們在CORE及NSGC中各定位66及39個數量性狀基因座 (Quantitative trait loci, QTL) ，利用各時間點的橫斷研究法所發現的QTL多與第一葉齡時期的時間點 (移植後第6-12天) 有關聯，所定位之QTL集中在數個同源連鎖群；而利用模型估計的方法所定位的QTL也是集中在數個同源連鎖群，但遺傳位置並不相同。不過，其中比較特別的是有兩組重疊的同源連鎖群：Mrg09、Mrg20、Mrg21及Mrg05、Mrg06、Mrg24，不但與株高的性狀有關，也同時發現與幼苗重量、模型估計的參數有關。此外，這些同源連鎖群中的遺傳區域，在前人的燕麥研究亦定位到與開花期、開花後株高，或是與植物防禦相關的QTL；我們將這些QTL相關序列與不同物種的序列比較後，發現預測之蛋白質功能與幼苗生長勢相關，因此我們認為未來若對這兩組同源連鎖群有進一步的探討，可以使我們對燕麥幼苗生長勢有更多的認識。

關鍵字

燕麥 (Arena sativa L.) ；幼苗生長勢；生長趨勢；全基因體關聯性分析；橫斷研究法

並列摘要

Oats (Avena sativa L.) rank the seventh cereal crop in the world in the term of production and cropping area, and are also an important forage crop for temperate, subtropical to tropical regions. Under an extensive management, strong seedling vigour is an important agronomic trait to assure a better weed competition at the early stage, and consequently a higher yield of biomass. However, there were few oat study that research oat seedling vigour. In this study, we conducted genome-wide association analysis based on 1,028 diverse oat accessions, including 650 cultivated elite oat accessions from Collaborative Oat Research Enterprise (CORE) and 378 oat landraces from USDA National Small Grains Collection (NSGC) in order to explore the genetic architecture of oat seedling vigour. In addition to traditional cross-sectional studies which assessed the phenotypes of interest at discrete time points, functional modeling was also used to estimate parameters related to the growth dynamics of oat seedlings. We detected 66 and 39 quantitative trait loci (QTL) in CORE and NSGC, respectively. Most of the QTL detected by cross-sectional study were associated with the time points at the first leaf stage (6-12 days after transplantation). QTL of similar traits were located on the homeologous linkage groups. QTL detected on growth parameters obtained using model fitting were also located on several homeologous linkage groups, but the genetic positon were different from those identified using cross-sectional traits. Two sets of homeologs of interest were identified: Mrg09, Mrg20, Mrg21 and Mrg05, Mrg06, Mrg24, which were not only associated to plant height, but also to seedling weight and growth parameters. In addition, those homeologs have been mapped previously for heading date, plant height after heading, or different plant defense responses. Comparing sequences of trait-associated marker with sequences from other cereal species showed that some markers were associated with seedling vigour related genes. Therefore, we believe that these two sets of homeologs merit further work to better understand seedling vigour in oats.

並列關鍵字

Oats (Arena sativa L.) ； Seedling vigour ； Growth dynamic ； Genome-wide association analysis (GWAS) ； Cross-sectional study

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利用全基因體關聯性分析解析燕麥幼苗生長勢的遺傳結構

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