Isolation Of Differentially Expressed Genes Under Salt Stress In Maize

Maize was one of the most important food and feed crops with important economic significance. With population increasing and infield reducing, Empoldering and using the pickled land, the area of which was very large was our inevitable choice, but the best viable approach was to breed salt tolerance or salt resistance crop varieties.Genetic improvement of maize salt tolerance was the main approach to increase the productivity under salt soil, but the mechanisms of maize salt tolerance were still unclear. As this research, two maize inbred lines were selected in which Mo17was salt-sensitive and TL94B was salt-tolerant, and200mmol/L of NaCl salt stress experiments were carried out indoors by sand cultivation in this research.The roots of Maize was sampled in5time stages and mRNA were isolated. Double-strained cDNA was synthesized using reverse transcriptase and was digested with EcoRI and Trul. Specifically designed adaptors were ligated to the ends of fragments. After pre-amplified with non-selective primers, the templates were diluted20-folds by water and then amplified with selective primers, The resulting products were size-fractionated on a5%polyacrylamide sequencing type gel and stained with silver.The results were as following:1. In this research, Sequencing and analyzing these differential expression genes,21kinds of ESTs were obtained totally among which42.8%had significant homology with known genes, including related to basic metabolism, related to protein synthesis, related to protein processing and destination, related to signal transduction, related to disease and defense response; the remaining51.2%ESTs were unknown12new-found ESTs.2. some ESTs were obtained which were considered to relative salt-tolerance gene, such as calmodulin-binding protein, phosphoethanolamine N-methyltransferase1GRF zinc finger family protein, and so on,.and the relationship of some ESTs between the salt-resistant crop were worth further research,such as NAD-dependent oxidoreductase.3. Through analyzing the expression characteristics of important candidate ESTs of salt tolerance, it showed that TL94B had faster and stronger responding to salt stress than Mo17, and it was benefited to protect cells from salt toxicity and to possess better salt tolerance. From these results, it deduced that the diversity of maize salt tolerance was related to responding speed and intensity of different genotypes to salt stress.