The Physical Locations Of Twelve Marker Loci Of Genetic Map In Hevea Brasiliensis

Natural rubber is an important industrial raw materials and strategic resources in our country. Hevea brasiliensis is the only commercial source of natural rubber because of the high production in glue and the high quality in product. Thus, it is an important economic crop for tropical and subtropical regions in our country. Predecessors had constructed a series of genetic maps of rubber tree by using different molecular marker techniques. However, The genetic maps could just reflect the relative positions and genetic distance between genes or DNA marker loci in the chromosomes. The true position and their distribution characteristics on chromosomes of the marker loci from genetic maps remain unclear. The correspondence relationships between the linkage groups and the karyotype are also unknown. In this study, we used fluorescence in situ PCR technology to locate the12markers from3linkage groups of the Hevea brasiliensis genetic map, and integrated the linkage groups and the karyotype about these markers. This research may establish the foundation for the construction of molecular cytogenetic map of Hevea brasiliensis. The results were as follows:(1) We had selected12markers from the molecules genetic map of rubber tree by Lespinasse in2000and designed the corresponding primers. Among these markers, five markers came from the linkage group1, they were gHbCIR78, gHbCIR611, M508, gHbCIR446and gHbCIR228; five markers came from the seventh linkage group7, they were gHbCIR648, gHbCIR400, gHbCIR598, gHbCIR105and gHbCIR531; two markers came from the linkage group11, they were gHbCIR507and gHbCIR215. The genomic DNA extracted from rubber tree was taken as template for PCR amplification with each pair of primers. And the gel electrophoresis result about PCR products indicated that only one band was found, respectively. After recovery and purification, these specific bands were all sequenced, and analyzed by BLAST. The analysis showed that the12pairs of primers were all specific primers.(2)The markers gHbCIR78, gHbCIR611, M508, gHbCIR446and gHbCIR228from the linkage group1were detected by IS-PCR. After karyotype analyzing, the markers gHbCIR78, gHbCIR611and M508were located on the long arm of the chromosome13of reyan7-33-97, the percentage distances from the centromere to signal were84.42,63.75and52.29, respectively. The markers gHbCIR446and gHbCIR228were located on the short arm of the chromosome13, the percentage distances from the centromere to signal were27.85and73.11, respectively. These results suggested that the five markers all were located on the chromosome13; the centromere was between M508and gHbCIR446; the order of the5markers on this chromosome was exactly consistent with the linkage group1; the linkage group1was assigned to chromosomes13.(3)The markers gHbCIR648, gHbCIR400, gHbCIR598, gHbCIR105and gHbCIR531from the linkage group7were detected by IS-PCR. After karyotype analyzing, the markers gHbCIR648, gHbCIR400, gHbCIR598and gHbCIR105were located on the long arm of the chromosome8of reyan7-33-97, the percentage distances from the centromere to signal were85.06,65.03,44.11and37.49, respectively. The marker gHbCIR531was located on the short arm of the chromosome8, the percentage distances from the centromere to signal was80.17. These results suggested that the five markers all were located on the chromosome8; the centromere was between gHbCIR105and gHbCIR531; the order of the5markers on this chromosome was exactly consistent with the linkage group7; the linkage group7was assigned to chromosomes8.(4)The markers gHbCIR507and gHbCIR215from the linkage group11were detected by IS-PCR. After karyotype analyzing, the marker gHbCIR507was located on the short arm of the chromosome16of reyan7-33-97, the percentage distances from the centromere to signal was33.31; the marker gHbCIR215was located on the long arm of the chromosome16, the percentage distances from the centromere to signal was23.94. These results suggested that the two markers all were located on the chromosome16; the centromere was between gHbCIR507and gHbCIR215; the linkage group11was preliminary assigned to chromosomes16.