The Preliminary Function Study Of ENDG1—the Early-period Response Gene For Rice Nitrogen Deficiency

Nitrogen as the main component of protein, is one of the major elements essential for plant growth. Nitrogen plays an important role in the growth and development of plants, and it is closely related to the yield. During the last three decades of crop planting, the excessive use of nitrogen fertilizers has a serious impact on the environment. Improving nitrogen use efficiency of crops can not only increase productivity, it also makes a great contribution to the protection of environment. With the deeper understanding of the molecular mechanisms of plant nitrogen uptake and utilization, the discovery of efficient varieties and relative new genes becomes one of the main focuses. Genome-wide cDNA microarray technology did a great job in the discovery and identification of genes. In the research, we did the screening of new genes associated with rice nitrogen metabolism by the genome-wide cDNA microarray technology, and chose ENDG1to do the further functional study. We already knew that ENDG1is a transcriptional factor belonging to AP2/ERF subfamily. The microarray data showed that within1h of the nitrogen deficiency treatment, ENDG1showed a rapid significant up-regulated expression. Both ammonium nitrogen and nitrate nitrogen had the approximate effect. We supposed that ENDG1is a gene that can show transient response to nitrogen deficiency. Analysis of gene expression patterns of ENDG1showed that it had significant specific expression in vascular bundle. Self-activating activity experiment was test in yeast strain Mav203. The full length of ENDG1was shown to have self activating activity. So we divided it into two parts and discovered that the C-terminal with the AP2domain was also shown to have self activating activity while the N-terminal without the AP2domain was not. Yeast two-hybrid experiment showed that the N-terminal could interact with a chitin-inducible gibberellin-responsive protein (CIGRP1). In addition, AP2/ERF family is a class of plant-specific transcription factor involved in plant development and stress resistance. Among different treatments, the expression level of ENDG1and CIGRP1showed similar response in ABA/Ethylene treatment and nitrogen deficiency, reflected in an apparent increase within30min. In addition, NaCl and mannitol treatments both raise the expression level of ENDG1and CIGRP1with in20min. Based on the results, we speculate that ENDG1can respond to the changes of the nitrogen concentration in time, and probably can interact with the ABA/Ethylene pathway to transmit the nitrogen deficiency signals to the down stream genes.