水稻幼苗在鹽逆境之根部數量性狀基因座定位分析

Quantitative trait loci mapping for rice root traits under salinity stress at seedling stage

林士弘(Shih-Hung Lin)

指導教授 ： 董致韡

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10392

摘要

水稻是世界上重要糧食作物之一，隨著人口增長，產量勢必要向上提昇。土壤鹽害是常見限制作物產量的非生物逆境，水稻在作物中屬於鹽敏感的作物，因此維持水稻在鹽逆境下的生長勢是日趨重要的議題。水稻面對鹽逆境時，根部首當其衝，影響著水稻對鹽分與養分吸收。本研究以 130 個秈稉雜交所產生的重組自交系族群及 196 個水稻種原為材料，調查幼苗期種子根、種子根上側根、冠根以及總根長在鹽逆境下的表現，發現根長性狀受鹽逆境抑制生長的程度不同；另外調查幼苗株高、鹽害指數等地上部性狀在鹽逆境中的反應，發現根部在鹽逆境長度愈大，通常幼苗株高也愈大。接著利用高密度單一核苷酸多型性分子標幟 (single nucleotide polymorphism, SNP) 進行單點分析 (single marker analysis) 並定位調控水稻耐鹽能力的數量性狀基因座 (quantitative trait locus, QTL)。本研究在兩族群中共偵測到 6 個基因座可能影響鹽害指數，我們分析鹽害指數表現優良的品系在這些基因座中的基因型，發現這些基因座偏屬japonica 次族群。另外 地上部性狀與根部性狀具有正相關性，但是並沒有偵測到相同的基因座；本研究亦定位到數個數量基因座可能影響根長性狀在鹽逆境的變異程度，在染色體 1、4、10 號上定位到重疊的基因座控制不同型態的根生長。鹽逆境中根部性狀表現優良的品系可以做為育種材料，經由分子標幟輔助育種將定位到的基因座導入現行品種，改良根部性狀在鹽逆境的生長勢。

關鍵字

水稻 ； 根部性狀 ； 鹽害 ； 鹽逆境生長勢 ； 單一核苷酸多型性 ； 關聯性定位法 ； 數量性狀基因座

並列摘要

Rice is one of the major crops in the world. Because human population grows, increasing rice production is necessary to meet human’s need. Salinity is a common abiotic stress to affect crop production, and rice is one of salt sensitive crops, therefore maintaining rice growth vigor under salt condition is an important issue. Root system is a major physical interaction between plants and soil substrates, it affects nutrients and salt absorption. In this research, we used two populations as study materials, one is recombinant inbred lines population derived from a cross between indica and temperate japonica, and a global diversity panel with 196 accessions. We measured root length under normal and salt condition at seedling stage, and found out degree of root growth vigor inhibited by salinity stress differs by root types. We used high density SNP markers to map QTLs controlling shoot and root growth in response to salt stress, many QTLs in RILs and in global diversity panel were mapped in this study. Although there was positive correlation between root and shoot traits under salinity stress, no identical QTLs were mapped. We selected accessions with good performance under salinity stress, these accessions will be good breeding materials to improve root vigor in elite cultivars, and through molecular assisted selection, QTLs with positive effect can be introduced to elite cultivars efficiently.

並列關鍵字

rice ； root traits ； salinity ； growth vigor under salinity stress ； SNP ； association mapping ； quantitative trait locus

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