Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA.
Department of Plant Sciences, North Dakota State University, Fargo, ND, 58108, USA.
BMC Plant Biol. 2021 Sep 29;21(1):441. doi: 10.1186/s12870-021-03197-x.
Soybean is an economically important crop which flowers predominantly in response to photoperiod. Several major loci controlling the quantitative trait for reproductive timing have been identified, of which allelic combinations at three of these loci, E1, E2, and E3, are the dominant factors driving time to flower and reproductive period. However, functional genomics studies have identified additional loci which affect reproductive timing, many of which are less understood. A better characterization of these genes will enable fine-tuning of adaptation to various production environments. Two such genes, E1La and E1Lb, have been implicated in flowering by previous studies, but their effects have yet to be assessed under natural photoperiod regimes.
Natural and induced variants of E1La and E1Lb were identified and introgressed into lines harboring either E1 or its early flowering variant, e1-as. Lines were evaluated for days to flower and maturity in a Maturity Group (MG) III production environment. These results revealed that variation in E1La and E1Lb promoted earlier flowering and maturity, with stronger effects in e1-as background than in an E1 background. The geographic distribution of E1La alleles among wild and cultivated soybean revealed that natural variation in E1La likely contributed to northern expansion of wild soybean, while breeding programs in North America exploited e1-as to develop cultivars adapted to northern latitudes.
This research identified novel alleles of the E1 paralogues, E1La and E1Lb, which promote flowering and maturity under natural photoperiods. These loci represent sources of genetic variation which have been under-utilized in North American breeding programs to control reproductive timing, and which can be valuable additions to a breeder's molecular toolbox.
大豆是一种经济上重要的作物，主要在光周期的作用下开花。已经确定了几个控制生殖时间数量性状的主要基因座，其中这三个基因座 E1、E2 和 E3 的等位基因组合是驱动开花和生殖期的主要因素。然而，功能基因组学研究已经确定了其他影响生殖时间的基因座，其中许多基因座的了解较少。更好地描述这些基因将使我们能够更好地微调对各种生产环境的适应。先前的研究表明，两个这样的基因 E1La 和 E1Lb 参与了开花，但它们的影响尚未在自然光周期条件下进行评估。
鉴定并导入了 E1La 和 E1Lb 的自然和诱导变体，并将其导入含有 E1 或其早开花变体 e1-as 的系中。在一个成熟组 (MG) III 生产环境中，对这些系进行了开花和成熟天数的评估。这些结果表明，E1La 和 E1Lb 的变异促进了更早的开花和成熟，在 e1-as 背景下的效果比在 E1 背景下更强。野生和栽培大豆中 E1La 等位基因的地理分布表明，E1La 的自然变异可能导致了野生大豆的北方扩张，而北美的育种种群利用 e1-as 来开发适应北方纬度的品种。
本研究鉴定了 E1 旁系同源物 E1La 和 E1Lb 的新等位基因，它们在自然光周期下促进开花和成熟。这些基因座代表了遗传变异的来源，在北美育种种群中，这些变异被低估了，它们可以作为育种者分子工具包的有价值的补充。
