  We show that in a system of one dimensional spinless fermions a topological
phase and phase transition can emerge only through interaction. By allowing a
dimerized or bond-alternating nearest neighbour interaction we show that the
system exhibits a symmetry protected topological phase while its
non-interacting limit is a gapless state. The non-trivial topological character
appears due to the onset of two degenerate bond-order phases as a function of
dimerized interaction which are found to be topologically distinct from each
other. As a result a topological phase transition occurs between these bond
order phases through a gap closing point. However, in the limit of strong
interaction, the bond order phases are connected through a gapped charge
density wave phase possessing local antiferromagnetic order. The topological
nature is characterized by the edge states, Berry phase and non-local string
order parameter. At the end we provide possible experimental signatures of the
emergent symmetry protected topological phase transition in terms of Thouless
charge pumping and density-density correlation.
