Functional Analysis of the Gossypium arboreum Genome

Gossypium arboreum is an Old World relative of the more commonly cultivated commercial species Gossypium hirsutum, a newer genetic line formed in the New World. G. arboreum has the important property that it can be cultivated in severely hot, dry climates. The genome of G. arboreum has not been completely sequenced, and annotation for the genome is not extensive. We studied the genome of G. arboreum by using cross-species hybridization studies with genomic microarrays for the more annotated species, Arabidopsis thaliana and Oryza sativa. Approximately 30% of the probes on the A. thaliana and O. sativa microarrays were hybridized effectively by target samples prepared from G. arboreum genomic DNA. Many of genes tentatively identified by hybridization function in various levels of the stress response. Cross-species hybridization can provide effective clues as to potentially valuable genes that may be present in a less well-studied species such as G. arboreum. The stress response genes tentatively identified in these studies should provide useful clues for further studies toward the development of hardier strains of cotton.