Characterization of multiple cold induced genes from Ammopiptanthus mongolicus and functional analyses of gene AmEBP1.

In comparison to herbaceous plants, studies of cold responsive genes and cold signaling in woody perennials are limited. Since most woody plants have evolved freezing tolerance (FT) in winter, together with similar lignified structures and winter adaptive mechanisms, it is more likely to find cold resistant genes in woody plants growing in temperate and arctic regions. In this study, Ammopiptanthus mongolicus, an evergreen, broadleaf and leguminous shrub was selected as a model to study cold tolerance in woody plants. Thirteen cold up-regulated cDNAs (including eight full-length cDNAs and five partial cDNAs) were cloned from A. mongolicus. One of these genes, AmEBP1, confers enhanced cold tolerance to E. coli and obvious increased freezing survival to Arabidopsis. In transgenic Arabidopsis expressing AmEBP1, transcript levels of some downstream genes in cold signaling exhibit increased accumulation upon cold treatment. Together with structural information, sub-cellular location, and promoter analysis data, it is suggested that AmEBP1 enhances plants cold tolerance by accelerating ribosome biogenesis and the concomitant translation of cold induced transcription factors and downstream protective proteins under cold stress.