Soybean is an important legume crop that displays the classic shade avoidance syndrome (SAS), including exaggerated stem elongation, which leads to lodging and yield reduction under density farming conditions. Here, we compared the effects of two shade signals, low red light to far-red light ratio (R:FR) and low blue light (LBL), on soybean status and revealed that LBL predominantly induces excessive stem elongation. We used CRISPR-Cas9-engineered Gmcry mutants to investigate the functions of seven cryptochromes (GmCRYs) in soybean and found that the four GmCRY1s overlap in mediating LBL-induced SAS. Light-activated GmCRY1s increase the abundance of the bZIP transcription factors STF1 and STF2, which directly upregulate the expression of genes encoding GA2 oxidases to deactivate GA₁ and repress stem elongation. Notably, GmCRY1b overexpression lines displayed multiple agronomic advantages over the wild-type control under both dense planting and intercropping conditions. Our study demonstrates the integration of GmCRY1-mediated signals with the GA metabolic pathway in the regulation of LBL-induced SAS in soybean. It also provides a promising option for breeding lodging-resistant, high-yield soybean cultivars in the future.

大豆是一种重要的豆类作物，表现出经典的避荫综合症（SAS），包括茎秆伸长过大，导致在密耕条件下倒伏和单产下降。在这里，我们比较了两种阴影信号（低红光与远红光之比（R：FR）和低蓝光（LBL））对大豆状态的影响，并揭示了LBL主要诱导茎过度伸长。我们使用了CRISPR-Cas9工程的Gmcry突变体来研究大豆中的七个隐色染料（GmCRYs）的功能，发现四个GmCRY1s在介导LBL诱导的SAS中重叠。光激活的GmCRY1s增加了bZIP转录因子STF1和STF2的丰度，后者直接上调了编码GA2氧化酶以灭活GA ₁的基因的表达。并抑制茎伸长。值得注意的是，在密植和间作条件下，GmCRY1b过表达品系均表现出优于野生型对照的多种农艺优势。我们的研究表明，GmCRY1介导的信号与GA代谢途径的整合可调控大豆LBL诱导的SAS。它还为将来培育抗倒伏，高产大豆品种提供了有希望的选择。