Spatial distribution of mRNA transcripts of chitinases class VII and beta-1,3-glucanases class II in flax zygotic and somatic embryo development

Abstract Key message The accumulation of mRNA transcripts of chitinases class VII and beta-1,3-glucanases class II decreases as embryo development progresses. In later stages, it occurs mainly in actively proliferating meristems. Abstract Besides being considered pathogenesis-related proteins, chitinases and β-1,3-glucanases are involved in many physiological and developmental processes. In this study, we investigated the potential role of specific β-1,3-glucanases class II and chitinases class VII in zygotic and somatic embryogenesis using in situ hybridization (ISH). The ISH experiments revealed that the mRNA transcripts of LuChitVII and LuGlucII, along with closely related chitinases and β-1,3-glucanases, accumulated during zygotic embryo development. In the earlier stages of embryo development, both probes showed uniform and relatively strong hybridization signals throughout the embryo. However, as development progressed, the signal intensity decreased. In the cotyledonary stage, the studied mRNA transcripts were more abundant in the meristems, with predominant accumulation in the basal part of the embryo. These structures are known for their high proliferation rates, suggesting the involvement of chitinases and β-1,3-glucanases in cell division. A similar expression pattern of both hydrolases was observed during somatic embryo development.