MSSM from SUSY trinification

We construct a SU(3)^3 supersymmetric gauge theory with a common gauge coupling g. Spontaneous breaking of this gauge group at a scale M_X=1.3\times10^{16} GeV gives naturally rise exactly to the Minimal Supersymmetric Standard Model (MSSM) and consequently to the experimentally favored values of sin^2\theta_w and \alpha_s.The gauge hierarchy problem is naturally solved by a missing-partner-type mechanism which works to all orders in the superpotential. The baryon asymmetry can be generated in spite of the (essential) stability of the proton. The solar neutrino puzzle is solved by the MSW mechanism. The LSP is a natural "cold" dark matter candidate and "hot" dark matter might consist of \tau-neutrinos. This model could be thought of as an effective 4d theory emerging from a more fundamental theory at a scale M_c=M_P/\sqrt{8\pi} where a_G\equiv{g^2\over{4\pi}} happens to be equal to unity