| Porphyra yezoensis is one of the most economically important species of the world in the genus and is also an ideal material for genetics and molecular biology research. Recently it has been suggested as a model plant in marine biological sciences for basic and applied studies because of its unique dimorphic generation cycle, apparently small genome size and chromosome number, and ease of reproducing a complete life cycle with in a few months in the laboratory culture system.To study the genes expression profile of different generations of P. yezoensis, 21,954 P. yezoensis EST were assembled and annotated. The result suggested that the expression level of ribosome protein genes were higher in gametophyte than in sporophyte. The expression level of Carbohydrate metabolism related genes were higher in sporophyte than in gametophyte.The gene profile chip plays an important role in the study of functional genome which can deal with a large amount of samples at one time. These two technologies have been used broadly in the clone of new genes,gene profile analysis of specific tissues and function annotation of the genome sequences as well as some other fields. So we can get a large quantity of expression information of function genes and differently expressed genes of related characters with expression profile chip in a short time. A cDNA microarry was used to analyze the gene Expression in P. yezoensis under Desiccation. In the whole course of desiccation, about 8.74%-11.09% of genes were increasingly expressed while the number of genes repressed is more variable. In the beginning of desiccation (desiccation degree 10%), 7.89% of genes were repressed expressed. In the mid phase of desiccation (desiccation degree 20%, 30%), about 5.76%-5.97% of genes were repressed expressed. When the degree of desiccation increasing to 40% and 50%, proportion of genes repressed expressed increased to 8.96%-10.45%. In the end of desiccation (desiccation degree 60%), only 4.05% of genes were repressed expressed. Many down-regulated genes turned to be up-regulated or expressed in the normal level. It indicated that it was helpful for P. yezoensis to be desiccated short time, but harmful for long time.In order to understand the mechanisms of signal transduction and anti-desiccation of P. yezoensis, cDNA and its genomic sequence of Calmodulin gene (CaM) was cloned by the technique of polymerase chain reaction (PCR) based on the analysis of P. yezoensis ESTs from GenBank dbEST. The result shows that the full-length cDNA of CaM consists of 603bps including an ORF encoding for 151 amino acid and a terminate codon UGA, while the length of genomic sequence is 1231bps including 2 exons and 1 introns. The average GC content of the coding region is 58.77%, while GC content of the third position of this gene is as high as 82.23%. Four Ca2+ binding sites (EF-hand) are found in this gene. The predicted molecular mass of the deduced peptide is 16688.72 Da and the pI is 4.222. By aligning with known CaM gene, the similarity of CaM gene sequence with homologous gene in Chlamydomonas incerta and Chlamydomonas reinhardtii is 72.7% and 72.2%, and the similarity of deduced amino acids sequence of CaM gene with homologous gene in C. incerta and C. reinhardtii are both 71.5%. This is the first report on CaM from a species of Rhodophyta.In the research, we have a more in-depth understanding to the genetic basis of P. yezoensis important characteristics. It provides more valuable information to select resistant, high quality, excellent characteristics of P. yezoensis, promote the sustained and healthy development of laver industry.
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