Use of

The present disclosure relates to the technical field of genetic engineering, and in particular to a use of a Glycine max GmSAMMT gene in regulation of a protein content and/or a yield of a plant. The present disclosure has proved through experiments that an expression level of the GmSAMMT gene in a GmSAMMT-knockout line is significantly lower than an expression level of the GmSAMMT gene in a control line, and a protein content and a seed weight of a GmSAMMT-knockout line are significantly higher than a protein content and a seed weight of a control line. Compared with the control line, in a GmSAMMT-overexpressed line, a transcription level of the GmSAMMT gene is significantly increased, a protein content is significantly reduced, and a seed weight is also reduced without a significant difference.