Screen of FISH marker of chromosomes at Gossypium D genome species

Appropriate centromere probes for fluorescence in situ hybridization (FISH) of cotton were screened and high density cytogenetic maps based on pachytene-FISH in D genome cotton were developed. A BAC library of Gossypium barbadense var. pima 90-53 was screened using two-dimensional PCR with molecular markers close to the centromere region and 12 BAC clones were identified by BAC-FISH. BAC clone 150D24 screened with SSR marker BNL3563,located at the end of long arm of Chromosome 10 was identified. Signals for BAC clone 150D24 were located in centromere regions of some shorter chromosomes in tetraploid cotton G. hirsutum (AD)1 and G. barbadense (AD)2. FISH conducted on diploid cotton demonstrated that there were clear signals in the centromere region of D genome diploid cotton species when BAC clone 150D24 was used as a probe. No signals were evident in A,C or E genome diploid cotton. This suggests that 150D24 contains repeat sequences,which are specific to D genome species centromere region; therefore,150D24 can be used as a specific FISH marker for centromere regions in D genome diploid cotton,including the D sub-genome.