Analysis Of Genetic Diversity Of Hawthorn Cultivars And Peach Varieties By RAPD And A New Gene Named Endoplasmic Reticulum Small Heat Shock Protein (ERsHSP) Cloned From Sweet Pepper.

This thesis consists of three parts: RAPD analysis of genetic diversity of different hawthorn cultivars, analysis of genetic diversity of peach varieties by RAPD, and a new gene named endoplasmic reticulum small heat shock protein (ERsHSP) cloned from sweet pepper.PartⅠ: The random amplified polymorphic DNA (RAPD) technique was used to determine the relative relationship among 20 hawthorn(Crataegus L.) cultivars of Shangdong province. 252 bands were generated by PCR as seventeen primers selected from 120 primers were used, of which 205 bands were polymorphic. The polymorphic rate was 81.3 %. There are also 37 specific bands in these polymorphic bands. The results indicated that there is high level of genetic diversity in the hawthorn cultivars. The NTSYS software and UPGMA method were used to calculate genetic similarity coefficient and cluster analysis. The results indicated that similarity coefficient was between 0.73～0.91, and an wild cultivar was far from others. The materials, primers and PCR amplification procedure used in this study were different from other people's. The researches in this paper may enrich the contents of hawthorn systematics and provide basic study for hawthorn germplasm in our country.PartⅡ: In order to study the origin of'Huangjinguan', the relative relationship between'Huangjinguan'and other varieties were studied using RAPD technique. Fifteen primers out of 80 arbitrary primers generated a total of 84 bands. The bands of amplified products were from three to ten, and the size of these ones were from 250bp to 3000bp. The NTSYS software and UPGMA method were used to calculate genetic similarity coefficient and cluster analysis.The results indicated that similarity coeffient was between 0.77～0.88. The relationship between'Huangjinguan'and Qinhuang 2 was the nearest, while Huangtao 19 was far from the other. This study provides a theoretical basis for exploitation of some special germplasm resources.PartⅢ: With the temperature-sensitive sweet pepper as experimental material, RT-PCR, 3′-RACE and 5′-RACE methods were used for cloning sweet pepper endoplasmic reticulum small heat shock protein gene(ERsHSP). Besides, the softwares of BLAST and DNAMAN were used for analysis of nucleotide and amino acid sequence between this gene and homologous genes. Analysis revealed that the ratios of the nucleotide and amino acid sequence homology were 74% and 76% respectively. Furthermore, expression vetors were constructed and teansformed to tobacco and the results showed that the high and low temperature resistances of transgenic tobacco were improved . The biological functions of sweet pepper ERsHSP were briefly analyzed.