Wu Jun, Li Lei-Ting, Li Meng, Khan M Awais, Li Xiu-Gen, Chen Hui, Yin Hao, Zhang Shao-Ling
Center of Pear Engineering Technology Research, Nanjing Agricultural University, Nanjing 210095, China.
International Potato Center (CIP), Apartado 1558, Lima 12, Peru.
J Exp Bot. 2014 Nov;65(20):5771-81. doi: 10.1093/jxb/eru311. Epub 2014 Aug 16.
Pear (Pyrus spp) is an important fruit crop, grown in all temperate regions of the world, with global production ranked after grape and apples among deciduous tree crops. A high-density linkage map is a valuable tool for fine mapping quantitative trait loci (QTL) and map-based gene cloning. In this study, we firstly constructed a high-density linkage map of pear using SNPs integrated with SSRs, developed by the rapid and robust technology of restriction-associated DNA sequencing (RADseq). The linkage map consists of 3143 SNP markers and 98 SSRs, 3241 markers in total, spanning 2243.4 cM, with an average marker distance of 0.70 cM. Anchoring SSRs were able to anchor seventeen linkage groups to their corresponding chromosomes. Based on this high-density integrated pear linkage map and two years of fruit phenotyping, a total of 32 potential QTLs for 11 traits, including length of pedicel (LFP), single fruit weight (SFW), soluble solid content (SSC), transverse diameter (TD), vertical diameter (VD), calyx status (CS), flesh colour (FC), juice content (JC), number of seeds (NS), skin colour (SC), and skin smooth (SS), were identified and positioned on the genetic map. Among them, some important fruit-related traits have for the first time been identified, such as calyx status, length of pedicel, and flesh colour, and reliable localization of QTLs were verified repeatable. This high-density linkage map of pear is a worthy reference for mapping important fruit traits, QTL identification, and comparison and combination of different genetic maps.
梨（Pyrus spp）是一种重要的水果作物，生长于世界所有温带地区，在落叶果树作物中，其全球产量仅次于葡萄和苹果。高密度连锁图谱是精细定位数量性状基因座（QTL）和基于图谱的基因克隆的宝贵工具。在本研究中，我们首先利用单核苷酸多态性（SNP）与简单序列重复（SSR）相结合构建了梨的高密度连锁图谱，这些SNP和SSR是通过快速且稳健的限制性内切酶相关DNA测序（RADseq）技术开发的。该连锁图谱由3143个SNP标记和98个SSR组成，共计3241个标记，跨度为2243.4厘摩（cM），平均标记间距为0.70 cM。锚定SSR能够将17个连锁群锚定到其相应的染色体上。基于此高密度整合梨连锁图谱以及两年的果实表型分析，共鉴定出11个果实性状的32个潜在QTL，这些性状包括果梗长度（LFP）、单果重（SFW）、可溶性固形物含量（SSC）、横径（TD）、纵径（VD）、萼片状态（CS）、果肉颜色（FC）、果汁含量（JC）、种子数（NS）、果皮颜色（SC）和果皮光滑度（SS），并将它们定位到遗传图谱上。其中，一些重要的果实相关性状如萼片状态、果梗长度和果肉颜色首次被鉴定出来，并且QTL的可靠定位经证实具有可重复性。该梨的高密度连锁图谱对于绘制重要果实性状、QTL鉴定以及不同遗传图谱的比较与整合具有重要参考价值。
