|J Integr Plant Biol, 55 (7): 654-662, Research Article|
|Uniqueness of the Gossypium mustelinum Genome Revealed by GISH and 45S rDNA FISH|
|Qiong Wu1,2, Fang Liu1, Shaohui Li1, Guoli Song1, Chunying Wang1, Xiangdi Zhang1, Yuhong Wang1, David Stelly3 and Kunbo Wang1*|
|1Cotton Research Institute, the Chinese Academy of Agricultural Sciences/National Key Laboratory of Cotton Biology, Anyang, China
2Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
3Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas, USA
Gossypium mustelinum ((AD)4) is one of five disomic species in Gossypium. Three 45S ribosomal DNA (rDNA) loci were detected in (AD)4 with 45S rDNA as probe, and three pairs of brighter signals were detected with genomic DNA (gDNA) of Gossypium D genome species as probes. The size and the location of these brighter signals were the same as those detected with 45S rDNA as probe, and were named GISH-NOR. One of them was super-major, which accounted for the fact that about one-half of its chromosome at metaphase was located at chromosome 3, and other two were minor and located at chromosomes 5 and 9, respectively. All GISH-NORs were located in A sub-genome chromosomes, separate from the other four allopolyploid cotton species. GISH-NOR were detected with D genome species as probe, but not A. The greatly abnormal sizes and sites of (AD)4 NORs or GISH-NORs indicate a possible mechanism for 45S rDNA diversification following (AD)4 speciation. Comparisons of GISH intensities and GISH-NOR production with gDNA probes between A and D genomes show that the better relationship of (AD)4 is with A genome. The shortest two chromosomes of A sub-genome of G. mustelinum were shorter than the longest chromosome of D sub-genome chromosomes. Therefore, the longest 13 chromosomes of tetraploid cotton being classified as A sub-genome, while the shorter 13 chromosomes being classified as D sub-genome in traditional cytogenetic and karyotype analyses may not be entirely correct.
Wu Q, Liu F, Li S, Song G, Wang C, Zhang X, Wang Y, Stelly D, Wang K (2013) Uniqueness of the Gossypium mustelinum genome revealed by GISH and 45S rDNA FISH. J. Integr. Plant Biol. 55(7), 654–662.
|Received: 28 March 2013 Accepted:|