Abstract
We have been studying on mechanisms of the sterility induced by high temperatures during microgametogenesis in rice. We have established an experimental procedure to evaluate high temperature injury in japonica rice plants. High temperature treatment (39C/30C) starting at the microspore stage repeatedly reduced following spikelet fertility in our system. To investigate gene regulatory mechanisms in the anther under high temperature conditions, DNA microarray analysis was performed. From clustering of microarray data, a series of genes down-regulated after two days treatment with high temperature were identified. Under normal conditions, these genes were expressed specifically in the tapetum cells at the microspore stage. We next isolated upstream regions of these genes and subjected to GUS reporter analyses to identify cis-elements regulating the high temperature response. As a result, several promoter regions including cis-elements responsible to tissue specificity and/or high temperature response were found. We are now attempting to carry out mutational analyses of these promoter regions in addition to functional analyses of these genes by gene knockdown experiments.
