Abstract
In natural environments, plants are exposed to combinations of different abiotic stresses. Especially, drought often accompanies with heat, which affects plant survival. However, the response of plants to heat/drought-combination stress is little known. Arabidopsis DREB2A is a transcription factor that activates gene expression in response to heat or drought stress. Thus, we analyzed stress-dependent regulation of DREB2A target genes.
When plants are treated with drought in addition to heat, expression of heat-specific genes was enhanced and leaf-surface temperature was elevated. These suggest that drought enhances heat stress and response.
To find elements that regulate stress-specific expression pattern, we produced transgenic Arabidopsis that express the GUSgene under the control of promoter fragments from DREB2A target genes. Expression patterns of GUS were similar to endogenous gene under drought and/or heat stresses, indicating that stress-specific expression patterns of DREB2A target genes are regulated by their promoter sequences.
