| Natural rubber is an important industrial raw materials and strategic resources. Hevea brasiliensis is the only commercial source of natural rubber because the rubber content exceeds50%in its latex and the economic life period of the trees is long.In Hevea brasiliensis, rubber biosynthesis occurs in a specialized latex-producing cell called laticfer, with sucrose as the primary substrate, and invertase acts as one of the key enzymes regulating the sucrose metabolism and determining the latex yield. Predecessors have cloned three neutral/alkaline invertase genes from Hevea brasiliensis. Jasmonic acid signaling pathway is important to regular the rubber biosynthesis. Genes associated with jasmonic acid signaling pathway include MYC family of transcription factors, JAZ protein family, HbCOI1gene and latex allergen protein Hev b gene family, some of them have been cloned. But the specific location of these genes on the chromosome has not been determined. In this research, chromosome specimens were prepared with immature leaves of Reyan7-33-97, fluorescence in situ hybridization(FISH) was used to physically locate HbNIN family. HbJAZ1ã€HbMYC1ã€HbMYC2, HbCOI1and Hev b7genes. The reseach would reveal the true position and distribution characteristics of these genes on the chromosomes, and the relationship with other genes. The results were as follow:(1) The members of HbNIN gene family were physically located on chromosomes of Reyan7-33-97by FISH. HbNIN1gene was located on the long arm of chromosome5of Reyan7-33-97, the percent distances from the gene locus to centromere was33.1; the HbNIN2gene was located on the long arm of chromosome2, the percent distances from the gene locus to centromere was35.7; the HbNIN3gene was located on the short arm of chromosome3, the percent distances from the gene locus to centromere was40.42.(2) The HbJAZJ, HbCOI1, HbMYCl, HbMYC2and Hev b7genes were physically located on the chromosomes of Reyan7-33-97by double-colour FISH. The results showed that HbJAZl gene was located on the long arm of chromosome4, the percent distances from the gene locus to centromere was47.29; the Hevb7gene was located on the long arm of chromosome11, the percent distances from the gene locus to centromere was40.26; the HbCOI1gene was located on the long arm of chromosome4, the percent distances from the gene locus to centromere was58.23; the HbMYC1ge13, the percent distances from the gene locus to centromere was68.73; the HbMYC2gene was located on the long arm of Chromosome3, the percent distances from the gene locus to centromere was26.82.(3) The method that the chromosome preparations were reused for the second time for FISH detection was established in this study, after the first FISH, chromosome preparation was put in1xPBS for20min, by70%,90%,100%ethanol gradient elution,5min each. Then put in1xPBS,5min each. Join different probes, hybridization and signal detection. Using this method, we detected the locus of HbNIN2and HbMYC2in FISH.(4) This research analyzed the linkage of eight genes located in this study and other genes located by predecessors:HbNIN3, HbMYC2genes were located on chromosome3, were linked genes; HbJAZl, HbCOI1were located on chromosome4, were linked genes; HbNIN1, HbNIN2, HbMYC1, Hev b7was independent gene each other. |
