| Phosphorus (P) is one of the important mineral nutrients for plant growth and development in higher plants. It is an important part of a series of important compounds, such as nucleotide, nucleic acid, nucleoprotein, phospholipid, ATP enzymes, in plants. Phosphorus in plants involved in various forms of life activities, such as energy metabolism, photosynthesis, signal transduction, etc, and has the property of high yield and good quality for crop. Plants absorb soluble phosphate in the soil mainly through root to meet their nutritional needs. According to estimates of soil survey data,1/3-1/2 of soil in China faces phosphorus deficiency. To solve the problem of insufficient available phosphorus in the soil, fertilization is used in production. A large number of phosphatic fertilizers applied in the soil were found in an invalid state, and the using efficiency was only 10%-25%. Large amount of phosphate Fertilizer added to soils causes depletion of phosphorus resources, and brings pollution to environmental and damaged ecological balance. Therefore, the use of the inherent biological characteristics in crops, digging phosphorus absorption potential in crops, cultivating phosphorus efficiency crop varieties is an important way to develop sustainable agriculture.Maize (Zea mays L.) is the most widely crop in the world, just following the wheat and rice. P deficiency is an important limit factor to the biomass and grain yield of corn. Currently, maize Breeding focused on yield and quality, little varieties possess high phosphorus use efficiency. Deficient phosphorus supplied in seedling will give rise to adverse effects, though provided enough phosphorus in the later stage. Therefore, in-depth study of phosphorus stress mechanism in maize seedlings provided theoretical basis for improving the quality and yield of maize and gain phosphorus efficiency maize.In recent years, research on maize phosphorus tolerance at home and abroad are very active, mainly focusing on morphology, physiology and changes in root characteristics.Proteins reflect the plant life activity directly as cell function performer. To the best of my knowledge, there are few research involved in proteomics of maize leaf. To further reveal the low phosphorus tolerance mechanism and its genetic basis of maize, this study selected Zhengdan958, cultivated by Henan Academy of Agricultural Sciences, and its parents as materials and analysed the leaf proteomics of these maize grown in culture medium for one month under phosphorus stress. Our results provided important information for In-depth study of phosphorus stress response genes and cultivation of phosphorus efficiency crops.Heterosis is a common phenomenon, meaning that at one or multiple traits, heterozygotes are better than the two parents. Using the principle of heterosis of is now the main method of crops breeding. In recent years, people has made great achievements on heterosis research in DNA and RNA level, however little has been done in protein. In this study, two-dimensional electrophoresis technology was applicated to study the proteomic of ZhengDan958 and its parents under the conditions of P deficiency. At the same time, polymorphism analysis was conduceted in Zheng58, ZhengDan958 and its parents.Based on the original laboratory technology, this study conducted 2-DE to analyse the proteome changes of seeding leaf coming from Zhengdan958 and its parents respectively grown in MS and MS-P. At the same time, we analyzed the genomic differences of Ye478, zhengdan958 and its parents using SSR markers. The results listed as follow:1. Mature embryo and immature embryo of ZhengDan958 and its parents were grown in MS and MS-P respectively. The results showed that survival rate of mature embryo in MS and MS-P was lower, respectively 10% and 20%. The plants growing up showed higher and stronger. The survival rate of imature embryo in MS and MS-P was ralativly higher, respectively 70% and 90%. The plants growing up showed dwarfish and weak.2. Protein extraction technology of tissue culture of maize seedlings was optimized to increase protein quality affected usually by the chlorophyll, phenols and quinines. This laid the technical foundation for the establishment of a stable and reproducible system of protein extraction and 2-DE system of green leaf.3.12 significantly different protein spots were analyzed by 3D map following analyzation of 2-DE figures of seedlings from MS and MS-P medium. The volume of different protein spots varied greatly, revealing the key differences between proteins of seedlings from MS and MS-P medium.4. Proteins from seedlings growing on complete medium and P deficiency medium were analyzed by ImageMaster 2D Platinum(Version6.0),617 and 580 protein spots were detected on map of ZhengDan958 CK and P deficiency ZhengDan958.220 protein spots were matched, of which 93 were up-regulated and 127 were down-regulated.555 and 431 protein spots were detected on map of Zheng58 CK and P deficiency Zheng58.224 protein spots were matched, of which 78 were up-regulated and 146 were down-regulated.218 and 213 protein spots were detected on map of Chang7-2 CK and P deficiency Chang7-2.107 protein spots were matched, of which 38 were up-regulated and 69 were down-regulated. Some different protein spots were detected among ZhengDan958 and its parents, which provided important information of proteomics for the futher study of heterosis of plant under phosphorus deficiency conditions.5. Protein ws extracted from maize seedlings growing up by mature embryos. Proteomics analysis was conducted by pH3-10 IPG and followed by mass spectrum (MS) to identify the differentially expressed proteins. Before and after treatment,12 proteins, belonging to 5 types, were identified. These proteins participated in transcriptional regulation, translation, phytoremediation, energy synthesis, photosynthesis. Of the 10 proteins, ATPaseβsubunit displayed down-regulation in Zheng58 after treatment and ATPaseδsubunit displayed down-regulation in Chang7-2 after treatment. However, ATPase in ZhengDan958 showed no obviously change. This may hinted that ZhengDan958 reflected the hybrid advantage in environment adaptation under P stress.6. Polymorphism screening and heterosis analysis were conducted using 200 SSR markers in Ye478, ZhengDan958 and its parents. The results showed that 60 of 200 SSR markers displayed Polymorphism between ZhengDan958 and its parents; 47 of 200 SSR markers displayed Polymorphism between Zheng58 and Ye478. SSR markers presented uneven distribution among different chromosomes, and in the same chromosome. These markers showed concentration in some area. These variation may proclaimed that specific chromosome were prone to occurred genetic recombination and mutation. These variation may have relation to yield coordination, which representing the specific heterosis of ZhengDan958.
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