Table_1_GmBICs Modulate Low Blue Light-Induced Stem Elongation in Soybean.XLSX

Blue-light inhibitors of cryptochromes (BICs) promote hypocotyl elongation by suppressing the activity of cryptochromes in Arabidopsis. Nevertheless, the roles of BICs in other plant species are still unclear. Here we investigate their functions by genetic overexpression and CRISPR/Cas9 engineered mutations targeting the six GmBIC genes in soybean. We showed that the GmBICs overexpression (GmBICs-OX) lines strongly promoted stem elongation, while the single, double, and quadruple mutations in the GmBIC genes resulted in incremental dwarfing phenotypes. Furthermore, overexpression of GmBIC2a abolished the low blue light (LBL)-induced stem elongation, demonstrating the involvement of GmBICs in regulating cryptochrome-mediated LBL-induced shade avoidance syndrome (SAS). The Gmbic1a1b2a2b quadruple mutant displayed reduced stem elongation under LBL conditions, which was reminiscent of the GmCRY1b-OX lines. Taken together, this study provided essential genetic resources for elucidating GmBICs functional mechanisms and breeding of shade-tolerant soybean cultivars in future.

隐花色素（cryptochromes）蓝光抑制剂（Blue-light inhibitors of cryptochromes，简称BICs）可通过抑制拟南芥（Arabidopsis）中隐花色素的活性，促进下胚轴伸长。然而，BICs在其他植物物种中的功能仍不明确。本研究通过遗传过表达及靶向大豆6个GmBIC基因的CRISPR/Cas9定向编辑突变，探究了其功能。研究显示，GmBICs过表达（GmBICs-OX）株系可显著促进茎伸长；而GmBIC基因的单突变、双突变及四突变体则呈现出递增的矮化表型。此外，GmBIC2a过表达可完全抵消低蓝光（LBL）诱导的茎伸长，证明GmBICs参与调控隐花色素介导的低蓝光诱导避荫反应综合征（SAS）。Gmbic1a1b2a2b四突变体在低蓝光条件下茎伸长受到抑制，该表型与GmCRY1b过表达（GmCRY1b-OX）株系相似。综上，本研究为解析GmBICs的功能机制及未来培育耐荫大豆品种提供了重要遗传资源。