Molecular Basis Of Somatic Embryogenesis In Rosa Chinensis

Rose, one of the traditional flower in China, have highly ornamental and commercial value in the world. Besides, the application of embryo genesis technology can greatly improve the efficiency of molecular breeding, such as reducing the chimera in transgenic plants and improving the efficiency of mutant screening. Currently, although the system of somatic embryogenesis have established in a few rose varieties, but the related molecular basis is still unknown. In this study, the leaf of Rosa chinensis’Yueyuehong’was used as experimental materials for callus induction. To indentify embryogenesis callus and non-embryogenesis callus, both general morphologic and microscopic observation were used in this study. The study on differentially expressed genes in somatic embryogenesis was laid a solid foundation for the molecular basis of gene regulation. The main results are as follows:i) Embryogenic and non-embryogenic callus was obtained and identified, somatic embryo was also successfully induced in this study.The experimental results indicate that significant differences in embryogenic callus differentiation rate on leaf induction, vary from0%to35%, was found in this study, even in the same culture conditions. This difference is inferred to different genotypes of rose plant. Meanwhile, the study through microscopic and ultra-microscopic observation also showed that the cell separation interval of embryogenic callus is more large than non-embryonic callus, and obviously starch accumulation was found in embryogenic callus,ii) Molecular marker research on differences in gene expression between non-embryonic and embryogenic callus.In this study, extracted high-quality RNA lay a solid foundation for the establishment of high-resolution cDNA-SRAP polyacrylamide gel electrophoresis. The result of electrophoresis shows that the difference in gene expression between embryonic and non-embryonic callus, in rate of23.89%, was happened in differentiation stage. Additionally, seven pairs of primer（Me7-Em8-Me7-Em1、Me3-Em8、Me3-Em5、Me2-Em11、 Me4-Em8、Me4-Em9） suitable for rose cDNA-SRAP was selected for experiment. Me2-Em11with36marker sites is one of the best primer pairs. iii) Two nucleic acid sequences of the gene showed significant dififerent expression between embryogenic and non-embryogenic callus were obtained.Two fragments, isolated from high-resolution polyacrylamide gel, were used for nucleotide sequence homology comparison in NCBI. The result shows that the homology between sequence No.1and XM₀04299313.1is up to96%. Besides, the result also shows that sequence No.2have high sequence conservation and the homology between Sequence No.2and auxin-responsive protein （IAA-like） is high.