Analysis Of The Digital Gene Expression Profiling Of Populus Tremula×P. Tremuloides Cuttings Development During Adventitious Roots Induction And Adventitious Roots Elongation

In our country, Populus tremula×P. tremuloide is important tree species of rapid propagation and ecological afforestation, which can quickly restore forest ecological environment and play a variety of benefits for forestry. For Populus tremula×P. tremuloide cutting with low rooting rate has been a major problem of breeders trees. In recent years, poplar whole-genome sequence has been cracked, With the growth and development of related gene expression mode has clear, This makes research workers have conditions to explore growth mechanism of trees at the molecular level.Populus tremula×P. tremuloide cuttingwood was chosen as the experimental materials to observe anatomy and morphology changes in adventitious rooting development phase; choose two important development phase(adventitious rooting development induction and elongation phase) and two parts (adventitious roots appear parts and stem parts) to acquire the genes which involved in adventitious roots development and analyse biological metabolic process which participated in with the use of solexa deep sequencing technology.Finaly, the molecular mechanism on adventitious developmet of Populus tremula×P.tremuloide cuttingwood was outlined to provide scientific basis for forest genetic engineering breeding. The result of this paper is as follows:(1) Morphological and anatomical studies of rooting:Populus tremula×P. tremuloide cuttingwood have complete anatomical structure in0day after cutting. In6day, phloem parenchyma cells divided speed, cuttingwood bottom swell and coarsen, which can be observed in external form. In9day, cells continue to divide and presented the obvious stratification, at this time, the root primordium was formed. Cuttingwood terminal have multiple white protuberances root, which can be observed in external form. In12day, root primordia continue to devide and elongate to form a root with complete root cap, meristematic zone and elongation zone.(2) Through analysis the tag sequences, the conclusions coule be made as:copy number is greater than100tag accounted for more than60%of the total, while in tag species is less than3%. Low copy tag (1-5copies) accounted for only about8%of the total Tag, while in tag species occupied the proportion of80%or more. This means that some of the high expression level of genes is likely plays an important role in Populus tremula×P. tremuloide cuttingwood adventitious root development phase.(3) Through comparison and analysis tag library with the use of solexa deep sequencing to screen differentially expressed genes and classfy their functions. We reference papers to select parts of adventitious root development related gene and count gene expression level in different phases and parts; construct phylogenetic tree among genes; analyse the specific role in adventitious root development phase. Focus on difference gene in adventitious root initiation site in the development phase (I-L vs E-L); conduct parthway significant enrichment analysis, identifying differentially expressed genes primarily involved in the metabolic pathway and signal transduction pathways.(4) Quantitative real-time PCR were carried out to test and verify authenticity of solexa sequencing consequence througu12genes which were selectef at random. Through the analysis found that:12genes have the consistent expression trend in two kinds of experimental technique, just as the calculation method and treated in a different way, so that the same genes in different calculation method have different multiple differences. In addition, also by real-time fluorescence quantitative PCR and semi quantitative PCR, ACTIN39(actin alfa-39chain) gene expression level was relatively stable, which can be used as a reference gene for other studies.