Heterologous Expression of the Chrysanthemum R2R3-MYB Transcription Factor CmMYB2 Enhances Drought and Salinity Tolerance, Increases Hypersensitivity to ABA and Delays Flowering in Arabidopsis thaliana

• DOI: 10.1007/s12033-011-9451-1
• Publication Date: 2011-09-07T08:36:52Z
• Authors: Hong Shan; Sumei Chen; Jiafu Jiang; Fadi Chen; Yu Chen; Chunsun Gu; Peiling Li; Aiping Song; Xirong Zhu; Haishun Gao; Guoqin Zhou; Ting Li; Xue Yang
• Keywords: 0303 health sciences; Chrysanthemum; Molecular Sequence Data; Arabidopsis; Salt-Tolerant Plants; Flowers; 15. Life on land; Plants, Genetically Modified; Adaptation, Physiological; 6. Clean water; Droughts; Cold Temperature; Plant Leaves; 03 medical and health sciences; Stress, Physiological; Amino Acid Sequence; Sequence Alignment; Phylogeny; Abscisic Acid; Plant Proteins; Transcription Factors

Knowledge on genes related to plant responses to adverse growth conditions and development is essential for germplasm improvement. In this study, a chrysanthemum R2R3-MYB transcription factor gene, designated CmMYB2 (GenBank accession No. JF795918), was cloned and functionally characterized. Expression of CmMYB2 in chrysanthemum leaves was up-regulated in response to drought, salinity and cold stress, as well as by treatment with exogenous abscisic acid (ABA). When the gene was constitutively expressed in Arabidopsis thaliana, it increased plant sensitivity to ABA and reduced stomatal aperture. Plant survival under drought was improved than in the wild type, as was the plants' salinity tolerance. The level of expression of a number of genes associated with the stress response, including RD22, RD29A, RAB18, COR47, ABA1 and ABA2, was raised in the CmMYB2 transgenic Arabidopsis plants. CmMYB2 transgenic Arabidopsis plants were also delayed in flowering. The expression of CONSTANS (CO), FLOWERING LOCUS T (FT), SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1), LEAFY (LFY) and APETALA1 (AP1) genes involved in flowering was down-regulated in the CmMYB2 transgenics. Together, these results suggest that CmMYB2 may be a promising gene for the drought and salt tolerance improvement and flowering-time modulation.