Department of Horticulture, The Pennsylvania State University, University Park, PA 16802, USA.
Genome. 2009 Nov;52(11):935-56. doi: 10.1139/g09-065.
The narrow genetic base of the cultivated tomato, Solanum lycopersicum L., necessitates introgression of new variation from related species. Wild tomato species represent a rich source of useful genes and traits. Exploitation of genetic variation within wild species can be facilitated by the use of molecular markers and genetic maps. Recently we identified an accession (LA2093) within the red-fruited wild tomato species Solanum pimpinellifolium L. with exceptionally desirable characteristics, including disease resistance, abiotic stress tolerance, and high fruit lycopene content. To facilitate genetic characterization of such traits and their exploitation in tomato crop improvement, we developed a new recombinant inbred line (RIL) population from a cross between LA2093 and an advanced tomato breeding line (NCEBR-1). Furthermore, we constructed a medium-density molecular linkage map of this population using 294 polymorphic markers, including standard RFLPs, EST sequences (used as RFLP probes), CAPS, and SSRs. The map spanned 1091 cM of the tomato genome with an average marker spacing of 3.7 cM. A majority of the EST sequences, which were mainly chosen based on the putative role of their unigenes in disease resistance, defense-related response, or fruit quality, were mapped onto the tomato chromosomes for the first time. Co-localizations of relevant EST sequences with known disease resistance genes in tomato were also examined. This map will facilitate identification, genetic exploitation, and positional cloning of important genes or quantitative trait loci in LA2093. It also will allow the elucidation of the molecular mechanism(s) underlying important traits segregating in the RIL population. The map may further facilitate characterization and exploitation of genetic variation in other S. pimpinellifolium accessions as well as in modern cultivars of tomato.
栽培番茄（Solanum lycopersicum L.）的遗传基础狭窄，因此需要从相关物种中导入新的变异。野生番茄物种是有用基因和性状的丰富来源。利用分子标记和遗传图谱可以促进野生物种内遗传变异的利用。最近，我们在红色果实野生番茄物种 Solanum pimpinellifolium L. 中发现了一个具有特殊理想特性的个体（LA2093），包括抗病性、非生物胁迫耐受性和高果实番茄红素含量。为了促进这些特性的遗传表征及其在番茄作物改良中的利用，我们在 LA2093 和一个先进的番茄育种系（NCEBR-1）之间的杂交后代中开发了一个新的重组自交系（RIL）群体。此外，我们使用 294 个多态性标记（包括标准 RFLP、EST 序列（用作 RFLP 探针）、CAPS 和 SSRs）构建了该群体的中等密度分子连锁图谱。图谱覆盖了番茄基因组的 1091 cM，平均标记间距为 3.7 cM。大多数 EST 序列主要基于其单基因在抗病性、防御相关反应或果实品质中的假定作用而被选择，这是首次将其映射到番茄染色体上。还检查了与番茄中已知抗病基因相关的 EST 序列的共定位。该图谱将有助于鉴定、遗传利用和定位 LA2093 中的重要基因或数量性状位点。它还将阐明在 RIL 群体中分离的重要性状的分子机制。该图谱还可以进一步促进其他 Solanum pimpinellifolium 个体以及现代番茄品种中遗传变异的特征和利用。
