AUTHOR=Mu Ruolan , Lyu Xiangguang , Ji Ronghuan , Liu Jun , Zhao Tao , Li Hongyu , Liu Bin 

TITLE=GmBICs Modulate Low Blue Light-Induced Stem Elongation in Soybean

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.803122

DOI=10.3389/fpls.2022.803122

ISSN=1664-462X

ABSTRACT=<p>Blue-light inhibitors of cryptochromes (BICs) promote hypocotyl elongation by suppressing the activity of cryptochromes in <italic>Arabidopsis</italic>. 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 <italic>GmBIC</italic> genes in soybean. We showed that the <italic>GmBICs</italic> overexpression (<italic>GmBICs-OX</italic>) lines strongly promoted stem elongation, while the single, double, and quadruple mutations in the <italic>GmBIC</italic> 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 <italic>Gmbic1a1b2a2b</italic> quadruple mutant displayed reduced stem elongation under LBL conditions, which was reminiscent of the <italic>GmCRY1b-OX</italic> lines. Taken together, this study provided essential genetic resources for elucidating GmBICs functional mechanisms and breeding of shade-tolerant soybean cultivars in future.</p>