IFEVA (CONICET-UBA), Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Ciudad Autónoma de Buenos Aires, Argentina.
Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Ciudad Autónoma de Buenos Aires, Argentina.
J Exp Bot. 2021 Jul 28;72(15):5426-5441. doi: 10.1093/jxb/erab191.
Plant density defines vegetative architecture and the competition for light between individuals. Brassica napus (canola, rapeseed) presents a radically different plant architecture compared to traditional crops commonly cultivated at high density, and can act as a model system of indeterminate growth. Using a panel of 152 spring-type accessions and a double-haploid population of 99 lines from a cross between the cultivars Lynx and Monty, we performed genome-wide association studies (GWAS) and quantitative trait locus (QTL) mapping for 12 growth and yield traits at two contrasting plant densities of 15 and 60 plants m-2. The most significant associations were found for time to flowering, biomass at harvest, plant height, silique and seed numbers, and seed yield. These were generally independent of plant density, but some density-dependent associations were found in low-density populations. RNA-seq transcriptomic analysis revealed distinctive latent gene-regulatory responses to simulated shade between Lynx and Monty. Having identified candidate genes within the canola QTLs, we further examined their influence on density responses in Arabidopsis lines mutated in certain homologous genes. The results suggested that TCP1 might promote growth independently of plant density, while HY5 could increase biomass and seed yield specifically at high plant density. For flowering time, the results suggested that PIN genes might accelerate flowering in plant a density-dependent manner whilst FT, HY5, and TCP1 might accelerate it in a density-independent. This work highlights the advantages of using agronomic field experiments together with genetic and transcriptomic approaches to decipher quantitative complex traits that potentially mediate improved crop productivity.
植物密度决定了植物的营养结构和个体之间对光的竞争。与传统的高密度作物相比，油菜（甘蓝型油菜、油菜）呈现出截然不同的植物结构，可作为不定型生长的模式系统。本研究使用了 152 个春油菜品种和 Lynx 和 Monty 杂交的双单倍体群体 99 个系的panel，对 12 个生长和产量性状在 15 和 60 株/m2 两种不同种植密度下进行了全基因组关联研究（GWAS）和数量性状位点（QTL）作图。最显著的关联是开花时间、收获时的生物量、株高、角果和种子数量以及种子产量。这些性状通常与种植密度无关，但在低密度群体中发现了一些密度依赖的关联。RNA-seq 转录组分析揭示了 Lynx 和 Monty 之间模拟遮荫下独特的潜在基因调控反应。在油菜 QTL 内鉴定出候选基因后，我们进一步研究了它们在拟南芥突变体中对某些同源基因密度响应的影响。结果表明，TCP1 可能独立于种植密度促进生长，而 HY5 可以在高种植密度下增加生物量和种子产量。对于开花时间，结果表明，PIN 基因可能以密度依赖的方式加速开花，而 FT、HY5 和 TCP1 可能以密度独立的方式加速开花。这项工作强调了使用农业田间试验与遗传和转录组方法相结合来破译潜在提高作物生产力的数量复杂性状的优势。
