Zn-deficiency responsive transcripts in Agrostis species revealed by mRNA differential display

As an essential component, Zinc (Zn) is required for the proper growth and functioning of plants. Belonging to the Poaceae family of grasses, characterization of Agrostis species in terms of Zn content and growth under low-Zn supply will not only enable a deeper understanding of the molecular mechanisms of metal homeostasis of these grass species but also contribute to the global efforts of micronutrient fortification in related grasses of great agronomic importance, such as barley and wheat. In this study, three Agrostis species, Creeping bentgrass (Agrostis stolonifera) , Colonial bentgrass (Agrostis capillaries), and Velvet bentgrass (Agrostis canina) , were analyzed for seed Zn content and the effects of Zn deficiency on growth. Although Velvet bentgrass exhibited the highest Zn levels in seeds, Creeping bentgrass was concluded to be the most tolerant variety to Zn deficiency. To explore differentially expressed genes under Zn deficiency, mRNA differential display approach was applied, which revealed six, one, and two differentially expressed genes in Creeping, Colonial, and Velvet bentgrasses, respectively. One of the differentially expressed genes in Creeping bentgrass was found to be significantly downregulated in response to Zn deficiency both under tissue culture and greenhouse conditions. Further analysis of this gene through rapid amplification of cDNA ends (RACE) revealed that the full-length gene exhibited extensive homology to the zinc transporter ZIP3 identified in Oryza sativa. These results suggest that conserved mechanisms may play a role in tolerance against Zn deficiency in some Agrostis species. Further dissection of these mechanisms may reveal elusive species-specific patterns of tolerance against deficiency for better utilization of Zn at cellular level