Root system architecture (RSA) manipulation may improve water and nutrient capture by plants under normal and extreme climate conditions. With the aim of initiating the genetic dissection of RSA in tomato, we established a defined ontology that allowed the curated annotation of the observed phenotypes on 12 traits at four consecutive growth stages. In addition, we established a quick approach for the molecular identification of the mutations associated with the trait-of-interest by using a whole-genome sequencing approach that does not require the building of an additional mapping population. As a proof-of-concept, we screened 4543 seedlings from 300 tomato M3 lines (Solanum lycopersicum L. cv. Micro-Tom) generated by chemical mutagenesis with ethyl methanesulfonate. We studied the growth and early development of both the root system (primary and lateral roots) and the aerial part of the seedlings as well as the wound-induced adventitious roots emerging from the hypocotyl. We identified 659 individuals (belonging to 203 M3 lines) whose early seedling and RSA phenotypes differed from those of their reference background. We confirmed the genetic segregation of the mutant phenotypes affecting primary root length, seedling viability and early RSA in 31 M4 families derived from 15 M3 lines selected in our screen. Finally, we identified a missense mutation in the SlCESA3 gene causing a seedling-lethal phenotype with short roots. Our results validated the experimental approach used for the identification of tomato mutants during early growth, which will allow the molecular identification of the genes involved.

中文翻译：

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一种用于鉴定和表征番茄早期生长突变体的快速方案

在正常和极端气候条件下，根系结构 (RSA) 操作可以改善植物对水分和养分的捕获。为了启动番茄中 RSA 的遗传解剖，我们建立了一个定义的本体，允许在四个连续生长阶段对 12 个性状的观察表型进行精选注释。此外，我们通过使用不需要构建额外映射群体的全基因组测序方法建立了一种快速方法，用于与感兴趣的特征相关的突变的分子鉴定。作为概念验证，我们从 300 个番茄 M3 系（Solanum lycopersicum L. cv. Micro-Tom）中筛选了 4543 株幼苗，该系通过用甲磺酸乙酯进行化学诱变产生。我们研究了根系（初级和侧根）和幼苗的地上部分以及从下胚轴出现的伤口诱导的不定根的生长和早期发育。我们确定了 659 个个体（属于 203 个 M3 品系），其早期幼苗和 RSA 表型与其参考背景不同。我们证实了突变表型的遗传分离，这些突变表型影响了我们筛选中选择的 15 个 M3 品系的 31 个 M4 家族中的初生根长度、幼苗活力和早期 RSA。最后，我们在 SlCESA3 基因中发现了一个错义突变，导致了具有短根的幼苗致死表型。我们的结果验证了用于在早期生长期间鉴定番茄突变体的实验方法，这将允许对所涉及的基因进行分子鉴定。