Characterization of a drought tolerance-related gene of Chinese cabbage in a transgenic tobacco plant

Drought is a major abiotic stress that affects plant growth and productivity in many regions of the world. As climate change has increased the incidence of drought, research of the genes related to drought stress and development of drought-tolerant plants is necessary now more than ever. In this study, genes related to drought tolerance were screened from Brassica rapa 135k microarray data and a gene with full-length sequence and unknown function was selected and named BrDSR28 (B. rapa drought stress resistance 28). The expression of BrDSR28 was over 4-fold higher in drought-tolerant Chinese cabbage than in wild-type controls. This gene contains a 483 bp open reading frame encoding a 160 amino acid polypeptide and it contains a senescence regulator domain. To characterize the function of BrDSR28, Nicotiana tabacum was transformed with over-expression and down-regulation vectors of the gene. Transgenic tobacco plants were confirmed by PCR, Southern hybridization, and RT-PCR analyses. The expression levels and phenotypes of the transgenic tobacco plants were analyzed under drought stress. The BrDSR28 over-expression lines showed higher expression of BrDSR28 in all stages of drought treatment and showed significant tolerance to drought when compared to the non-transgenic lines and BrDSR28 down-regulated tobacco plants.