Genomics analysis of genes expressed reveals differential responses to low chronic nitrogen stress in maize
A growth system was developed where N was the only growth-limiting factor. Whole-genome transcription profiling of leaf tissues were analyzed using the Affymetrix GeneChip. 129 clones showed significant change and 83 clones were classed accurately. Most induced clones were largely involved in various metabolism processes including physiological process, organelle regulation of biological process, nutrient reservoir activity, transcription regulator activity and multicellular organismal process. Putative high affinity nitrate transporter (nrt2.1) showed significant up-regulation under the severe low chronic nitrogen stress condition. Analysis of genes expression revealed several previously unidentified
genes, including beta-D-glucosidase precursor gene (glu2), and Cyc3 cyclin3 gene. It suggests that under the said condition, nrt2.1 plays the most important role in N absorption and most of the other genes induced expression to enable the maize to have normal growth. A better understanding of the complex regulatory network for plant N responses among these genes will help and lead to improve N use efficiency.
Key words: Genomics analysis, genes expressed, low chronic nitrogen stress, maize.