Validation and fine mapping of lyc12.1, a QTL for increased tomato fruit lycopene content
Validation and fine mapping of lyc12.1, a QTL for increased tomato fruit lycopene content
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DOI：
10.1007/s00122-013-2126-5
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发表时间：
2013-08-01
影响因子：
5.4
通讯作者：
Foolad, Majid R.
中科院分区：
文献类型：
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作者：
Kinkade, Matthew P.;Foolad, Majid R.
番茄红素是番茄（Solanum lycopersicum L.）果实品质，是许多番茄育种计划的重点。两个增加果实番茄红素含量的QTL，遗传自一个高番茄红素S。pimpinellifolium accession，以前检测到番茄染色体7和12上使用S. lycopersicum x S. pimpinellifolium RIL群体中的基因，并被确定为潜在的目标分子标记辅助选择和定位克隆。为了验证这两个QTL的表型效应，从选择的RIL和S.番茄轮回亲本BC2群体田间生长，并使用HPLC评价果实番茄红素含量。统计分析显示，虽然lyc7.1在杂合条件下没有显著增加番茄红素含量，但在杂合条件下携带lyc12.1的个体含有比轮回亲本高70.3%的番茄红素。为了消除果实大小的潜在多效性效应并使lyc12.1基因渗入的物理大小最小化，进行标记辅助的回交程序并产生分离lyc12.1的BC3S1 NIL群体（n = 1，500）。测定了该群体中lyc12.1纯合和杂合重组体的番茄红素含量，并将lyc12.1定位于1.5cM区域。此外，我们确定lyc12.1被限定为与番茄12号染色体的1.5 Mb序列相似，并提供了一些对该区域潜在候选基因的见解。所获得的亚近等基因系将为lyc12.1基因向其它番茄遗传背景的转移以及该QTL的进一步定位和克隆奠定基础。
Lycopene content is a key component of tomato (Solanum lycopersicum L.) fruit quality, and is a focus of many tomato-breeding programs. Two QTLs for increased fruit lycopene content, inherited from a high-lycopene S. pimpinellifolium accession, were previously detected on tomato chromosomes 7 and 12 using a S. lycopersicum x S. pimpinellifolium RIL population, and were identified as potential targets for marker-assisted selection and positional cloning. To validate the phenotypic effect of these two QTLs, a BC2 population was developed from a cross between a select RIL and the S. lycopersicum recurrent parent. The BC2 population was field-grown and evaluated for fruit lycopene content using HPLC. Statistical analyses revealed that while lyc7.1 did not significantly increase lycopene content in the heterozygous condition, individuals harboring lyc12.1 in the heterozygous condition contained 70.3 % higher lycopene than the recurrent parent. To eliminate the potential pleiotropic effect of fruit size and minimize the physical size of the lyc12.1 introgression, a marker-assisted backcross program was undertaken and produced a BC3S1 NIL population (n = 1,500) segregating for lyc12.1. Lycopene contents from lyc12.1 homozygous and heterozygous recombinants in this population were measured and lyc12.1 was localized to a 1.5 cM region. Furthermore, we determined that lyc12.1 was delimited to a similar to 1.5 Mb sequence of tomato chromosome 12, and provided some insight into potential candidate genes in the region. The derived sub-NILs will be useful for transferring of lyc12.1 to other tomato genetic backgrounds and for further fine-mapping and cloning of the QTL.