Germins and germin like proteins: an overview

Molecular investigations during wheat germination have revealed unique developmentally regulated proteins, designated as germins, which show remarkable resistance to broad specificity proteases and to dissociation in SDS. Germins in cereals have an oxalate oxidase activity, which generates H2O2 from the oxidative breakdown of oxalate thereby playing a significant role in plant development and defense. Germin like proteins (GLPs) exhibit sequence and structural similarity with the cereal germins but mostly lack oxalate oxidase activity. Germins and germin like proteins (GLPs) are a class of developmentally regulated glycoproteins characterized by a beta-barrel core structure, a signal peptide, and are associated with the cell wall. GLPs exhibit a broad range of diversity in their occurrence and activity in organisms ranging from myxomycetes, bryophytes, pteridophytes, gymnosperms and angiosperms. Germins and GLPs are thought to play a significant role during zygotic and somatic embryogenesis (wheat and Pinus, respectively), salt stress (barley and Mesembryanthemum crystallinum), pathogen elicitation (wheat and barley), and heavy metal stress, etc. Characterization and cloning of some of the genes encoding germins and GLPs has facilitated a better understanding of their regulation and raised their potential of biotechnological application.