Acclimation Of Arabidopsis Floral Development and Transcriptome To Drought

Plants are sessile and must withstand different environmental stresses, such as drought, salt and various temperatures. Such stresses often greatly reduce plant reproductive yield, but studies of the effects of environmental stress have largely focused on vegetative development. In addition, detailed analyses of reproductive development have been performed using plants grown under favorable conditions. Therefore, relatively little is known about plant reproductive development under stressful conditions. We have devised a system of regular watering that presents persistent drought, which nevertheless allows the Arabidopsis plant to initiate and complete reproductive development, and used this scheme to investigate plant responses to drought during reproductive development at both the morphological and transcriptomic levels. Drought treatment lasted from after flowering to seed maturation and caused an early arrest of floral development and sterility and then prolonged reduction of fertility. Floral developmental defects included ovule abortion, failure of flower to open, abnormal anther development, and delayed filament elongation. Drought also caused differential expression of >4100 genes, including flowering time genes FT, SOC1, LFY, many anther and pistil genes. Also induced were genes known to be induced in leaves by drought. Lost-of-function mutations in some of these genes showed floral defects under drought, suggesting that they are important for drought response in Arabidopsis flowers. Our results indicate that drought induced floral transcriptome share similar genes to those in leaves, but also have relatively distinct sets, suggesting flowers might have some specific regulatory mechanisms for drought response.