Expansion and evolution of thaumatin-like protein (TLP) gene family in six plants

Thaumatin-like protein (TLP) is one of pathogenesis-related protein family, which plays an important role in plant defense system. While its origin and expansion is unknown in plants. Here, we investigated the evolution of this gene family by performing a genome-wide identification and comparison in Arabidopsis, Oryza, Populus, Zea, Physcomitrella and Chlamydomonas. We found a birth process of this gene family in evolution. Tandem and segmental duplication played dominant roles for their expansion. In addition, TLPs were under purifying selection, and most members were responding to some biotic or abiotic stresses. Functional network analysis exhibited some resistance genes working together with TLPs. Our findings shed some light on this family gene evolution in plants, which might provide a base for further functional investigation of this family.