Development Of High-resolution Cytological Map And Karyotype Analysis Based On45S RDNA And Telomere-FISH In Jatropha Species

Jatropha is one of the most important energy plants in the world,which has a high content oil up to40%-60%. The molecular ingredient of oil is very similar to petroleum and even more stable than petroleum. Jatropha oil can be made into different kinds of oil for different usage. It has become one of the most studied energy plants internationally, which can produce biodiesel.However,due to high concentrated cytoplasm and small chromosomes,cytogenetical study is rare on jatropha. Thus, it is of great significant to study cytology, analyze the karyotype and build a high-resolution chromosome map of jatropha.In this study, we first explored the method for establishing the high resolution map of jatropha. On this basis, using45S rDNA and telomere-DNA as probes, fluorescence in situ hybridization (FISH) was performed to establish a clear, accurate karyotype diagram, Meanwhile, we analyzed45SrDNA in different varieties, the results are as follows:(1) In the chromosome preparing technology of jatropha, root length, pretreatment time and enzymatic factors are important factors for the chromosome preparing. When the root is1.5to2.0cm in length, pretreated2hours with0.002mol/L8-hydroxyquinoline, at37℃enzymatic1.5h, the chromosome enrichment was suitable, uniformly dispersed and clearly formed. The cells divided more and covered without cytoplasm. Phase the jatropha pollen mother cells in diameter to about2mm get more split.(2)Based on the Karyotype analysis of45S rDNA and telomere-FISH, the karyotype formula of the Jatropha is2n=2x=22=12m+10sm, with an average arm ratio of1.784.The range of variation of the Jatropha chromosome relative length is between4.404and10.706and the ratio of the longest chromosome to the shortest is2.431.(3)The distribution of45S rDNA on different sources of Jatropha chromosomes makes no obvious difference. They all have four45S rDNA sites and are located at the end of two pairs of homologous chromosomes. The dispersion of the45S rDNA signals are related to the state of the chromosome。...