Abstract
TCP (TEOSINTEB RANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR) is a plant-specific transcription factor family that is closely associated with plant growth and development. To date, a few studies have been conducted on the TCP family of soybean. To investigate the function of the TCP transcription factor family in soybeans, we conducted a series of experiments and obtained significant results. Our detailed research on GmTCP670 revealed that its full length was 1128 bp encoding 375 amino acids, with no introns or untranslated regions. ExPASy prediction showed that the isoelectric point (pI) of GmTCP670 was 8.14, and its molecular weight (Mw) was 42.49 kDa. The flowering time of the GmTCP670 overexpression transgenic line was delayed compared with that of the control Dongnong 50 (DN50) and the CRISPR/Cas9 edited line (GmTCP670-CC). The leaves of the transgenic plants were larger, and the leaf type changed from pointed leaves of the receptor pro-Dongnong 50 to rounded leaves. The plants were taller than both their parental lines and the GmTCP670-CC lines, with maturity occurring 13 days later. The total amino acid, total essential amino acid, and arginine contents in the GmTCP670-CC transgenic line obtained through gene editing were higher than those in the DN50 and GmTCP670-OE lines. The GmTCP670 transcription factor recognizes GGACCC elements, binds to them, and activates the reporter gene expression. In addition, the GmTCP670 transcription factor interacted with the protein encoded by Glyma.18G297100 and activated reporter gene expression. This study provides basic theoretical data for future studies on the regulation of GmTCP670 transcription factors in soybean development and improvement, as well as on the underlying molecular mechanisms.