Cloning and Mapping of a New MYB Transcription Factor (GhTF1) in Cotton

Plant MYB transcription factors are characterized by the presence of a structurally conserved MYB domain, with important roles in regulation of plant development and metabolism. To clone new MYB genes and furthermore put a foundation to illustrate the function of these genes in cotton (Gossypium spp.) fiber developmental stages, a MYB transcription factor gene, GhTF1 (GenBank No. EF651783) was isolated from developmentally different cotton fiber pools of elite material “7235”. The gene has a 771 bp open reading frame and encodes a polypeptide containing 256 amino acids. Gene GhTF1 showed different expression levels in all tissues, e.g., with higher levels in fiber cells at initiation and elongation stages. The gene had conserved coding region in A and D diploid cotton species, G. herbaceum and G. raimondii. However, there existed a large DNA fragment insertion/deletion and base substitutions in their corresponding intron regions. Southern blotting analysis showed that there were 2 copies of GhTF1 in the genome of upland cotton, deducing with each copy in the sub-genome At and sub-genome Dt. GhTF1 was located on chromosome 10 by the BC1 mapping population derived from the hybridization between an upland cotton standard line TM-1 (recurrent parent) and G. barbadense cultivar Hai 7124.