Fig. 6

Expression analysis of GmBBX genes under salt treatment. A Transcript profiling of GmBBX genes based on RNA-Seq analysis. The heatmap was generated with the FPKM values of the 22 salt-stress-responsive GmBBXs using the online tool, TBtools, and the color scale beside the heat map indicates gene expression levels, low transcript abundance indicated by blue color and high transcript abundance indicated by red color. The 22 salt-stress-responsive GmBBXs were classified into three groups Group I, GmBBX3d/11a/11d/15d/21 g/28d/28f/30a/30b; Group II, GmBBX19c/19d/21b/21c/21d/21e/28a; Group III, GmBBX3b/10b/21a/28 g/32a/32b. B Gene expression patterns of GmBBX genes using qRT-PCR analysis. Soybean seedlings were exposed to the salt stress of 200 mM NaCl for 0, 6, 12, 24, 48 and 72 h, and total RNAs for RNA-Seq and qRT-PCR analysis were extracted from salt-treated seedlings at the six above-mentioned timepoints. The qRT-PCR data were normalized against GmSUBI3, and the expression level at the first timepoint (0 h) was set as 1. Error bars indicate SE of three biological and technical replicates, and significant differences are denoted by asterisk(s) (p < 0.01 or p < 0.05)