The present invention relates generally to the field of molecular biology and concerns a method for enhancing yield-related traits in plants by modulating expression in a plant of one or more nucleic acid(s) encoding at least two iSYT (interactor of SYT-synovial sarcoma translocation-) polypeptides. The present invention also concerns plants having modulated expression of a nucleic acid encoding at least two iSYT polypeptides, which plants have enhanced yield-related traits relative to corresponding wild type plants or other control plants. The invention also provides hitherto unknown nucleic acids encoding at least two iSYT polypeptides, and constructs comprising the same, useful in performing the methods of the invention. The invention also provides constructs useful in the methods of the invention. Furthermore the present invention also relates to an iSYT-based protein complex. It further relates to the use of the complex to promote plant growth, and to a method for stimulating the complex formation, by overexpressing at least two members of the complex.