中國農業科學 ?? 2019, Vol. 52 ?? Issue (12): 2033-2041.doi: 10.3864/j.issn.0578-1752.2019.12.002

? 作物遺傳育種·種質資源·分子遺傳學 ? 上一篇    下一篇

一個高抗玉米南方銹病基因的QTL定位及遺傳分析

王兵偉,覃嘉明(),時成俏,鄭加興,覃永嬡,黃安霞   

  1. 廣西農業科學院玉米研究所,南寧 530007
  • 收稿日期:2019-02-03 接受日期:2019-04-21 出版日期:2019-06-16 發布日期:2019-06-22
  • 通訊作者: 覃嘉明 E-mail:[email protected]
  • 作者簡介:王兵偉,E-mail: [email protected]
  • 基金資助:
    國家自然科學基金(316603991005418);廣西自然科學基金(2015GXNSFAA139057);廣西農業科學院科技發展基金(桂農科2016JM02);廣西農業科學院基本科研業務專項(桂農科2018YM19);廣西農業科學院基本科研業務專項(2015YT25)

QTL Mapping and Genetic Analysis of a Gene with High Resistance to Southern Corn Rust

WANG BingWei,QIN JiaMing(),SHI ChengQiao,ZHENG JiaXing,QIN YongAi,HUANG AnXia   

  1. Maize Research Institute, Guangxi Academy of Agricultural Science, Nanning 530007
  • Received:2019-02-03 Accepted:2019-04-21 Online:2019-06-16 Published:2019-06-22
  • Contact: JiaMing QIN E-mail:[email protected]

摘要:

【目的】 通過對一個熱帶高抗玉米南方銹病材料S313與4個高感玉米南方銹病材料組配的8個F2群體進行兩年三季的遺傳分析,在表型鑒定的基礎上,利用其中1個F2群體進行局部遺傳圖譜構建及抗性基因定位,并利用大群體及新開發的分子標記對抗性主效QTL進行精細定位,為進一步克隆該基因奠定基礎。【方法】 連續三季對8個F2分離群體,分3個時期進行病原菌接種,玉米生長后期按1—9級標準等級記載各單株的抗南方銹病級數,進行抗性表型鑒定,最終確定抗、感分離比例。利用56K芯片篩選出2個親本間多態標記,選擇其中均勻分布的192個標記對S313×PHW52的F2群體中各30個高抗、高感子代進行KASP分型。利用第10染色體短臂上19個SNP標記對整個F2群體進行分型,構建局部遺傳圖譜;將遺傳圖譜與田間抗性表型鑒定結果相結合進行抗性QTL定位。開發初定位區間內10個SNP標記對次級群體進行標記分型,根據交換單株數量大小進一步縮小定位區間。根據玉米B73 Ref Gen_V4參考基因組信息,列出對應定位區間內的所有基因,利用基因的功能注釋信息,確定可能與玉米抗南方銹病相關的候選基因。【結果】 8個F2群體田間抗、感分離比均符合3﹕1的分離比例,說明熱帶自交系S313對玉米南方銹病的抗性是由1個效應比較大的主效QTL控制。利用56K芯片篩選出2個親本間的多態標記16 426個。利用192個標記對各30個抗、感子代進行連鎖分析,獲得了1個抗性連鎖標記Affx-90241059。利用19個SNP標記構建了總遺傳距離為31.8 cM,標記間平均距離1.77 cM的局部遺傳圖譜。利用復合區間作圖法把該主效QTL定位在標記Affx-91298359與標記Affx-91182449之間,區間大小約2 M。進一步利用F2大群體及10個SNP標記把該區間縮小到474 K的范圍內。玉米參考基因組B73的對應區間內共有63個基因,其中3個基因LOC103640657LOC100191493LOC103640673編碼的蛋白質與植物抗病性有關,因此把這3個基因列為熱帶玉米種質S313高抗玉米南方銹病的抗性候選基因。【結論】 S313對玉米南方銹病的抗性是由1個主效QTL控制,并且S313的主效基因定位在第10染色體短臂約0.47 M的范圍內。在該范圍內有3個玉米南方銹病抗性候選基因。

關鍵詞: 玉米, 南方銹病, 抗性, QTL定位

Abstract:

【Objective】This study aimed at constructing regional genetic map and positioning the resistant gene to Southern Corn Rust by using one of the 8 F2 populations, deriving from crosses of the highly resistant tropical maize line S313 with 4 highly susceptible inbred lines to Southern Corn Rust, in 3 seasons of two years. In addition, a major QTL for Southern Corn Rust resistance was fine-mapped by applying new-developed molecular markers to a larger mapping population.【Method】Total 8 F2 populations were planted in 3 consecutive seasons of 2016 and 2017, all of which received triple inoculation. Individual F2 plants grown in the field were scored for resistance to southern rust using a nine-point relative scale at late growth stage. Finally, the segregation ratio of resistant to susceptible plants for each F2 population was investigated by phenotypic identification. A 56K-SNP chip was used for screening polymorphisms between the two parents, among which 192 SNP markers were picked for genotyping the 30 high resistant and 30 susceptible plants in an F2 population of S313×PHW52. Nineteen newly developed SNP markers on the short arm of chromosome 10 were used for genotyping the whole F2 population and constructing a regional genetic map. The resistant QTL mapping was proceeded by the combination of genetic map and phenotypic identification. The genotyping to second population with 10 newly developed SNP markers within the initial mapping region was performed, and the interval was delimited according to the number of exchanged plants. According to the information of maize B73 genome, all genes in corresponding interval were listed. By the gene functional annotation information, the candidate genes were determined.【Result】 By Chi-square test, the ratio of resistant plants to susceptible plants in these 8 F2 populations was all statistically a 3:1 ratio, which indicated that the resistance to Southern Corn Rust of S313 was controlled by a main effect QTL. A total of 16426 polymorphic markers between the two parents were screened out from the 56K-SNP chip. A resistance-linked marker Affx-90241059 was identified by the linkage analysis of 30 resistant and 30 susceptible plants with 192 markers of uniform distribution across chromosomes. A regional genetic map with total distance of 31.8cM and average distance 1.77 cM was constructed by using 19 SNPs. By the composite interval mapping method, the main effect QTL was located within the interval between marker Affx-91298359 and marker Affx-91182449, which size was 2M approximately. Furtherly, the interval was delimited to the size of 474K by using a larger F2 population and 10 SNP markers. There are 63 genes in the 474k interval of B73 reference genome, among which, gene LOC103640657, LOC100191493 and LOC103640673 encode plant disease resistance-related proteins. Thus, these three genes were listed as candidate genes resistant to Southern Corn Rust of tropical maize inbred line S313. 【Conclusion】 By field phenotypic identification, the ratio of resistant plants to susceptible plants in all F2 populations was determined as 3:1, which indicated that the resistance to Southern Corn Rust of S313 was under controlled by a main effect QTL. By the methods of population construction and molecular marker, the main effect QTL of S313 was located in the interval of about 0.47M size on the short arm of maize chromosome 10. There are 3 candidate genes related to Southern Corn Rust in this region.

Key words: maize, southern corn rust, disease resistance, QTL mapping

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