| Cotton is an important cash crop in the world. As the main product of cotton, cotton fibers have been become an important material for the textile industry, and its quality affects quality and efficiency of textile.Therefore, it has been the primary task of cotton molecular breeding that improving cotton fiber quality.Cotton fibers are differentiated and developed from the single epidermal cell of the ovule. Elongation and the final length of cotton fiber are far exceeds other plant cells, which is the ideal model plant of cell elongation and cell wall biosynthesis in the study. It is essential that cloning genes related to cotton fiber development and researching molecular mechanisms for improving cotton fiber quality by using genetic engineering.Proline-rich protein is a class of proline-rich and hydroxyproline-rich cell wall structural proteins. It is not only able to resist external pathogens, respond to hormonal induction and abiotic stress, but also play an important role in plant growth and development. In this study, using electronic sequences spliced and RT-PCR technology, a new gene encoding proline-rich protein was isolated from 12 days post anthesis( DPA) cotton fiber, and designated as Gh PRP10(Accession No. KP036633). In this study, we preliminary analyzed the gene function by studying the expression profile in different tissues of cotton and observing phenotype of transgenic model plants. The main results are as follows:1. The ORF of the gene was 687 bp encoding 228 amino acids, contained 34.6% proline. The bioinformatics analysis showed that the protein encoded by this gene belonged to the first class of PRPs,which has a signal peptide in N terminal and a proline rich conserved region.2. The Quantitative Real-time PCR results showed that Gh PRP10 is preferentially expressed in cotton fiber. The transcript level increased along with fiber development and reached the highest abundance at18 DPA, after which time(21-27DPA) it gradually decreased. It is presumed that the gene plays an important role in the process of fiber elongation and secondary wall synthesis.3. To further study the function of genes Gh PRP10, the plant over-expression vector was constructed by using Gateway technology and transformed into tobacco BY-2 suspension cells, SR1 tobacco, and Arabidopsis Columbia respectively by agrobacterium-mediated genetic transformation. The phenotype observation and cell length measurement found that the transgenic cells were significantly longer than that of the wild type. By measuring the plant Arabidopsis root length and leaf area, the statistical analysis showed that the whole plant leaf area of transgenic Arabidopsis was significantly larger than that of??wild type, and the roots of transgenic Arabidopsis were significantly longer than that of wild-type,suggesting that the Gene may play an important role in plant growth and development. Green fluorescent protein(GFP) fusion vectors of Gh PRP10 was constructed and transformed into tobacco leaves. The analysis of transient expression showed that the gene is located in the cell edge. Interference vector and overexpression vector of Gh PRP10 was constructed and transformed into cotton YZ-1 to obtain resistant plants, which laid the foundation for further study of the gene function in cotton fibers. |
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