<i>CT2</i> is involved in yield-related traits and cell proliferation of maize.

Heterotrimeric G-proteins are multifunctional modulators that participate in a wide range of growth and developmental processes in eukaryotic species, including yeast, plants, and animals. In this study, we characterized a maize mutant, <i>ct2</i>, that showed a compact architecture and reproductive-organ-related phenotypic variation. Heredity analysis indicated that the mutant phenotypes resulted from monogenic inheritance. The target gene, <i>CT2</i>, was cloned using bulked segregant analysis and map-based cloning. Sequence alignment showed that the <i>ct2</i> mutation was the result of a 185-bp sequence insertion at the 3' terminal of <i>CT2</i>. Protein structure prediction and phylogenetic analysis indicated that CT2 is a canonical Gɑ of monocotyledonous plants. Through phenotypic identification, we found that <i>CT2</i> was involved in yield-related traits in maize. Furthermore, our findings indicated that <i>CT2</i> promotes cell proliferation in stem internodes, which may result from the upregulation of zeatin biosynthesis by <i>CT2</i>. This research provides direction for further studies in the biological function of <i>CT2</i> in cell proliferation and in yield-related traits, which will be beneficial for maize breeding through screening and application of beneficial alleles.