AUTHOR=Byun Mi Young , Cui Li Hua , Lee Jungeun , Park Hyun , Lee Andosung , Kim Woo Taek , Lee Hyoungseok 

TITLE=Identification of Rice Genes Associated With Enhanced Cold Tolerance by Comparative Transcriptome Analysis With Two Transgenic Rice Plants Overexpressing DaCBF4 or DaCBF7, Isolated From Antarctic Flowering Plant Deschampsia antarctica

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00601

DOI=10.3389/fpls.2018.00601

ISSN=1664-462X

ABSTRACT=<p>Few plant species can survive in Antarctica, the harshest environment for living organisms. <italic>Deschampsia antarctica</italic> is the only natural grass species to have adapted to and colonized the maritime Antarctic. To investigate the molecular mechanism of the Antarctic adaptation of this plant, we identified and characterized <italic>D. antarctica C-repeat binding factor 4</italic> (<italic>DaCBF4</italic>), which belongs to monocot CBF group IV. The transcript level of <italic>DaCBF4</italic> in <italic>D. antarctica</italic> was markedly increased by cold and dehydration stress. To assess the roles of <italic>DaCBF4</italic> in plants, we generated a <italic>DaCBF4</italic>-overexpressing transgenic rice plant (<italic>Ubi:DaCBF4</italic>) and analyzed its abiotic stress response phenotype. <italic>Ubi:DaCBF4</italic> displayed enhanced tolerance to cold stress without growth retardation under any condition compared to wild-type plants. Because the cold-specific phenotype of <italic>Ubi:DaCBF4</italic> was similar to that of <italic>Ubi:DaCBF7</italic> (Byun et al., <xref ref-type="bibr" rid="B12">2015</xref>), we screened for the genes responsible for the improved cold tolerance in rice by selecting differentially regulated genes in both transgenic rice lines. By comparative transcriptome analysis using RNA-seq, we identified 9 and 15 genes under normal and cold-stress conditions, respectively, as putative downstream targets of the two <italic>D. antarctica</italic> CBFs. Overall, our results suggest that Antarctic hairgrass <italic>DaCBF4</italic> mediates the cold-stress response of transgenic rice plants by adjusting the expression levels of a set of stress-responsive genes in transgenic rice plants. Moreover, selected downstream target genes will be useful for genetic engineering to enhance the cold tolerance of cereal plants, including rice.</p>