Figure 5.

Subgenome‐biased expression of PACLOBUTRAZOL RESISTANCE 1 (PRE1) in allotetraploid cottons. (a) Schematic representation of PRE1 gene and nucleotide polymorphisms in the coding region of PRE1 homoeologs (PRE1A and PRE1D) in allotetraploid cottons. P1 and P2 indicate locations of primers used in pyrosequencing. The single nucleotide polymorphisms (SNPs) used for genotyping the homoeologous pair are indicated by underlining. Identical sequences are not shown. (b–d) PRE1 shows a striking expression bias toward the At homoeolog in ovules and fibers of (b) Gossypium hirsutum, (c) G. barbadense and (d) G. darwinii. (e) Both At and Dt copies of PRE1 were expressed in ovules and fiber cells of G. tomentosum, a wild allotetraploid cotton species endemic to the Hawaiian Islands. All pyrosequencing assays were repeated three times with similar results, and representative results are shown. The routine technical error of pyrosequencing is c. 5%. DPA, days post‐anthesis.