Functional Verification of the Soybean Pseudo-Response Factor GmPRR7b and Regulation of Its Rhythmic Expression

The pseudo response regulator (<i>PRR</i>) gene is an important component of the core oscillator involved in plant circadian rhythms and plays an important role in regulating plant growth and development and stress responses. In this study, we investigated the function of <i>GmPRR7b</i> by overexpression and gene editing approaches. It was found that <i>GmPRR7b</i> plays a role in delaying flowering. While <i>GmPRR7b</i> overexpressing plants showed significantly delayed flowering compared to untransformed WT, <i>GmPRR7b</i> edited plants flowered earlier than the control WT. On the basis of previous research results and bioinformatics analysis, we re-identified 14 soybean <i>PRR</i> genes and analysed their rhythmic expression. Based on the rhythmic expression pattern, we found that GmPRR5/9a and GmPRR5/9b interacted with GmPRR7b by yeast two-hybrid and bimolecular fluorescence complementation (BiFC) experiments. Combined with the expression regulatory networks of the <i>GmPRR7b</i>, we inferred a possible regulatory mechanism by which <i>GmPRR7b</i> affects flowering through quit rhythm expression. These research elements provide valuable references for understanding growth, development, and circadian regulation in soybean.