Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV) Universitat Politècnica de València, Spain.
BMC Plant Biol. 2011 Oct 20;11:140. doi: 10.1186/1471-2229-11-140.
Low regeneration ability limits biotechnological breeding approaches. The influence of genotype in the regeneration response is high in both tomato and other important crops. Despite the various studies that have been carried out on regeneration genetics, little is known about the key genes involved in this process. The aim of this study was to localize the genetic factors affecting regeneration in tomato.
We developed two mapping populations (F2 and BC1) derived from a previously selected tomato cultivar (cv. Anl27) with low regeneration ability and a high regeneration accession of the wild species Solanum pennellii (PE-47). The phenotypic assay indicated dominance for bud induction and additive effects for both the percentage of explants with shoots and the number of regenerated shoots per explant. Two linkage maps were developed and six QTLs were identified on five chromosomes (1, 3, 4, 7 and 8) in the BC1 population by means of the Interval Mapping and restricted Multiple QTL Mapping methods. These QTLs came from S. pennellii, with the exception of the minor QTL located on chromosome 8, which was provided by cv. Anl27. The main QTLs correspond to those detected on chromosomes 1 and 7. In the F2 population, a QTL on chromosome 7 was identified on a similar region as that detected in the BC1 population. Marker segregation distortion was observed in this population in those areas where the QTLs of BC1 were detected. Furthermore, we located two tomato candidate genes using a marker linked to the high regeneration gene: Rg-2 (a putative allele of Rg-1) and LESK1, which encodes a serine/threonine kinase and was proposed as a marker for regeneration competence. As a result, we located a putative allele of Rg-2 in the QTL detected on chromosome 3 that we named Rg-3. LESK1, which is also situated on chromosome 3, is outside Rg-3. In a preliminary exploration of the detected QTL peaks, we found several genes that may be related to regeneration.
In this study we have identified new QTLs related to the complex process of regeneration from tissue culture. We have also located two candidate genes, discovering a putative allele of the high regeneration gene Rg-1 in the QTL on chromosome 3. The identified QTLs could represent a significant step toward the understanding of this process and the identification of other related candidate genes. It will also most likely facilitate the development of molecular markers for use in gene isolation.
低再生能力限制了生物技术的繁殖方法。基因型对番茄和其他重要作物的再生反应有很大影响。尽管已经进行了各种关于再生遗传学的研究，但对参与这一过程的关键基因知之甚少。本研究旨在定位影响番茄再生的遗传因素。
我们从一个再生能力低的番茄品种（cv. Anl27）和野生种 Solanum pennellii（PE-47）的高再生品系中开发了两个作图群体（F2 和 BC1）。表型分析表明，芽诱导呈显性，外植体的芽诱导率和再生芽数均呈加性效应。通过区间作图和限制多 QTL 作图两种方法，在 BC1 群体中，在五个染色体（1、3、4、7 和 8）上共鉴定到 6 个 QTL。这些 QTL 来自 S. pennellii，除了位于第 8 号染色体上的小 QTL 是由 cv. Anl27 提供的。主要 QTL 与在第 1 号和第 7 号染色体上检测到的 QTL 相对应。在 F2 群体中，在与 BC1 群体中检测到的 QTL 相似的区域，也鉴定到一个第 7 号染色体上的 QTL。在这些区域观察到标记与 BC1 的 QTL 分离的偏分离。此外，我们使用与高再生基因连锁的标记定位到两个番茄候选基因：Rg-2（Rg-1 的一个假定等位基因）和 LESK1，它编码丝氨酸/苏氨酸激酶，被提议作为再生能力的标记。因此，我们在第 3 号染色体上检测到的 QTL 中定位到一个假定的 Rg-2 等位基因，我们将其命名为 Rg-3。位于第 3 号染色体上的 LESK1 也不在 Rg-3 之外。在对检测到的 QTL 峰的初步探索中，我们发现了一些可能与再生有关的基因。
本研究从组织培养中鉴定到了与复杂再生过程相关的新 QTL。我们还定位到了两个候选基因，在第 3 号染色体上的 QTL 中发现了高再生基因 Rg-1 的一个假定等位基因。所鉴定到的 QTL 可能是对这一过程的理解和其他相关候选基因的鉴定的重要一步。它也很可能有助于开发用于基因分离的分子标记。
