Identification Of Novel Stress Responsible Transcription Factors Using DNA Array Hybridization

Drought and salt loading are two major dehydration stresses that cause adverse effects on plant growth and the productivity of crops. In order to reduce the threat to crops posed by environmental stresses, an essential step towards understanding plant responses to environmental stresses is to identify genes involved in the stress responses.Numerous studies have shown that array of transcription factors have roles in regulating plant responses to environmental stresses. A small portion of them, however, have been identified or characterized. In this study, a matured technology—DNA array was employed to identify novel transcription factors involved in plant responses to abiotic stresses in a high throughput fashion.Based on the annotation, more than 2300 putative transcription factors were predicted in rice genome and classified by gene family. More than half of them were supported by expressed sequences. We made a comprasion between rice and Arabidopsis in the distribution of gene families of transcription factors. It was suggested that the percentage of transcription factor genes in different families in rice was generally similar to that in Arabidopsis.With an attempt to identify novel stress responsive transcription factors, a DNA array containing 753 putative rice transcription factors was generated to analyze the transcript profiles of these genes under drought and salinity stresses and ABA treatment at seedling stage of rice. About 80% of these transcription factors showed detectable level of transcript in seedling leaves, and no transcription factor gene family showed predominance. A total of 18 up-regulated transcription factors and 29 down-regulated transcription factors were detected with the folds of changes ranging from 2.0 to 20.5 in at least one of the stress treatments. A total of 44 transcription factors were involved. Most of these stress-responsible genes have not been reported.To validate the stress-responsive TFs identified from array hybridization and further analyze their expression pattern under stresses, five TF genes, representing low (2-3 folds), mediate (4-6 folds) and high level (>8 folds) of differential expression, were chosen for Northern analysis. All the selected genes showed stress-induced or suppressed expression and were in agreement with the array results. More detailed information about...