FemAB_like is a family of both baterial and Viridiplantae proteins with responsibility for building interpeptide bridges in peptidoglycan. Such a function is feasible for bacteria but less likely for the plant members of this family. Perhaps the plant-members are using homologous proteins to recognise bacterial peptidoglcans as part of their innate immune system [1].

1: The challenge of annotating protein sequences: The tale of eight domains of unknown function in Pfam. Goonesekere NC, Shipely K, O'Connor K; Comput Biol Chem. 2010;34:210-214. PMID:20537955