G₂(2) as the automorphism group of the octonionic root system of E₇

A simple method is suggested for the construction of the seven-dimensional representation of the adjoint Chevalley group G₂(2), the automorphism group of the octonionic root system of E₇. The maximal subgroups of G₂(2) preserving the octonionic root systems of the maximal subgroups of E₇ are identified. Possible implications in physics are discussed.