2015-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/700126摘要：稻熱病菌可為害各生育期的水稻，是全球稻米生產之重要威脅。為減少病害發生及農藥使用，種植抗病品種為現行主要防治策略，然而田間稻熱病菌族群組成複雜且變異頻繁，造成抗病品種往往在大面積種植後數年即失去其抗性。為解決上述問題，須深入瞭解水稻之抗性遺傳因子，及其與國內稻熱病菌主要生理小種之對應關係。本計畫的主要目標，是結合連鎖定位 (linkage mapping) 及關聯定位 (association mapping) 兩種數量遺傳分析方式，廣泛解構臺灣水稻品種中調控稻熱病抗性之R genes及防禦相關基因/基因座，以提供分子育種及病害防治策略擬定之參考。本研究首先將使用具同樣遺傳背景但帶有不同R genes之判別品種，篩選出3種具代表性的臺灣稻熱病菌生理小種，據此建立人工接種及抗性檢定系統。隨後將以具有優良抗稻熱病特性之台農84號、具有良好農藝特性但甚為感病之台南11號為主要對象，建立「台南11號x台農84號」之F2、F3分離群系，並開發多型性分子標誌，進行高通量基因型分析 (方法包括High-resolution melting analysis、Fragment analysis、KASPar genotyping、Fluidigm genotyping等)。其結果經bulked segregant analysis及 (inclusive) composite interval mapping分析後，即可初步定位出主效基因及QTLs位置。在此同時，將使用自美國引進之rice diversity panel (共有來自82國家的413歧異品種、具44100 SNPs)，加上台南11號、台農84號及13種具代表性的國內常見水稻栽培品種 (預定進行Illumina低覆蓋率定序)，一併以稻熱病菌接種評估後，進行全基因體關聯定位 (genome-wide association study, GWAS)，期望以最有效率的方式，精準分析出臺灣常見水稻品種中與稻熱病抗性調控有關的基因及/或序列，作為發展分子標誌輔助育種，及深入探討抗性機制之基礎。<br> Abstract: Rice blast, caused by Magnaporthe oryzae, is a serious constraint to rice production worldwide. The use of resistance varieties is a widely adopted non-chemical strategy for effective control of this disease. The resistance of rice lines, however, can often be overcome after a few years of widespread cultivation. This is mainly due to the complex genetic diversity of M. oryzae populations and their high mutation rates at avirulence loci. To solve the problem, it is important to understand the underlying genetics of blast resistance and the composition of M. oryzae races in the field. This study aims to dissect the resistance genetics of rice cultivars in Taiwan, using a combination of two quantitative genetics approaches - linkage mapping and association mapping. With differential lines carrying different known R genes in the same genetic background, we will first identify three representative M. oryzae races in Taiwan. Phenotypic evaluations of the mapping materials will then be carried out on the basis of artificial inoculations with the three pathogen races in the greenhouse or growth chamber condition. For linkage mapping, F2 and F3 populations will be derived from the cross of “Tainan 11 x Tainung 84” (Tainan 11: a most widely cultivated variety, with good agronomic traits but susceptible to blast; Tainung 84: a recently released variety, with high level of blast resistance), and polymorphic PCR-based markers and high-throughput genotyping techniques (eg. High-resolution melting analysis, Fragment analysis, KASPar genotyping, or Fluidigm genotyping) will be developed/applied. By conducting bulked segregant analysis (BSA) and (inclusive) composite interval mapping, major-effect R genes and quantitative trait loci (QTLs) conditioning blast resistance can be identified at low resolution. For high resolution mapping, we plan to conduct genome-wide association study (GWAS) using the “rice diversity panel”, which is a set of 413 japonica and indica rice lines (collected from 82 countries) with publicly available genotyping data (44100 single nucleotide polymorphisms), in combination with “a selected set of blast resistant/susceptible cultivars in Taiwan” (Tainan 11, Tainung 84 and additional 13 cultivars). In order to include local cultivars in the association analysis, these lines will be genotyped by Illumina next-generation sequencing technology at low coverage. With the integrated linkage and association mapping strategy, we expect to effectively uncover not only blast QTLs but also potential R genes, defense-related genes, and/or causative regulatory sequences in the genomes of important rice cultivars in Taiwan. Candidate genes/sequences identified in this study can be used as selection markers in rice resistance breeding programs. Our understanding of resistance mechanisms will also facilitate the development of new approaches for controlling blast disease.Magnaporthe oryzae生理小種判別品種連鎖定位全基因體關聯定位抗病遺傳台農84號台南11號次世代定序Magnaporthe oryzaephysiological racesdifferential lineslinkage mappinggenome-wide association mappingresistance geneticsTainung 84Tainan 11next-generation sequencing