Primary Study Of Differential Proteomics About Nitrogen Utilization In Different Elite Maize Inbred Lines

Maize (Zea mays L) is one of the most important foods and the average yield is highest in the world. All over the world, increase the nitrogen fertilizer application rate is an important measure to increase maize production right now. However, application of nitrogen fertilizer only increase yield to a certain extent, excessive use not only bring more economic burden to producers and caused serious environmental problems. Study the Elite Maize Inbred Lines with different sensitivity of nitrogen response especially and the different mechanism of nitrogen use are conducive to clear the emergency activate mechanism in low nitrogen stress of bear low nitrogen corn variety, lay the foundation for breeding the variety with high use efficiency of fertilizer.Huangzaosi and Mo17 the Elite Maize Inbred Lines was studied in this paper, they were widely used in breeding, Huangzaosi was seen as bear low nitrogen variety and Mo17 was not bear low nitrogen. Study the difference of the plant type and dry matter accumulation between these two varieties under taking the Ca(NO₃)₂ for the nitrogen source and setting a gradient of 0mmol /L,2mmol / L,4mmol / L,8mmol / L soil-free cultivation condition. After that using 2D electrophoresis technology analyze the differences of the leaf proteome expression. The follows are the results:1. In the earlier vegetative growth period Huangzaosi's leaf area is smaller, length is shorter and the material accumulation quantity is also less than Mo17. But in later period of mature time Huangzaosi's dry material accumulation quantity are almost the same to Mo17. This means Huangzaosi accumulation more dry material than Mo17 in mature time. And Huangzaosi's differences exhibitions are less than Mo17 between gradients. Huangzaosi have almost the same biological productions between gradients 4mmol/L and 8mmol / L. So mine infers according to the above is Huangzoasi is not as sensitive as Mo17 to the nitrogen.2. Analysis Huangzaosi and Mo17 leaf expressing proteome in each nitrogrn levels during seeding stage and shooting stage with 2D-electrophoretic. The result shows that Huangzaosi expressing more protein spots than Mo17, maybe this is the reason why Mo17 is as sensitive as Huangzaosi to the nitrogen. Analysis the same inbreeding line 2D picture, using peptide mass fingerprinting analysis 28 spots the result shows that most of the protein spots are unknown protein and come from other kind of plants.3. Ribulose-1,5-bisphosphate carboxylase/ oxygenase large subunit has been found in both Huangzaosi and Mo17 in the seeding stage. And the ribulose-1,5-bisphosphate carboxylase / oxygenase large subunit expression level increased with the nitrogen gradient in both Huangzaosi and Mo17. In the same nitrogen gradient ribulose-l,5-bisphosphate carboxylase / oxygenase large subunit expression level in Huangzaosi is higher than Mol7. This maybe the reason Huangzoasi is not as sensitive as Mo17 between the nitrogen levels.4. Cysteine protease inhibitor is found in both seeding stage of Huangzoasi and jointing stage of Mo17. This proved the cysteine protease inhibitor is as a kind of adversity stress protein also has effect in maize stress resistance. In the seeding stage of Huangzoasi the cysteine protease inhibitor expression level is increased with the nitrogen gradient, but in the jointing stage of Mo17 the cysteine protease inhibitor expression level is decreased with the nitrogen gradient. This maybe another reason for Huangzoasi is not as sensitive as Mo17 between the nitrogen levels.5. A class of NBS-LRR protein which is known coding by disease-resistant gene is found in Mo17 jointing stage, this is the first time this protein found in adversity stress maize. Extrapolation this protein has an effect to corn's resistance. But how this protein participates in the entire process of nitrogen metabolism, and the protein's function are not known. So further study about this protein are need.