Plant breeders have discovered the key genetic information determining leaf shape in cotton. Researchers from North Carolina State University (NC State) and colleagues from Donald Danforth Plant Science Center, U.S. Department of Agriculture, and Cotton Incorporated describe how genomic and molecular tools were used to find the location of the DNA sequence that determines major leaf shapes in upland cotton. The researchers also described how they manipulated the genetic code to alter the shape of a cotton plant's leaves in potentially beneficial ways.

Cotton plants with leaves that have five deep lobes, like the leaves of the okra plant, offer advantages to farmers over what researchers refer to as "normal" leaves. The "okra" leaf cottons are less susceptible to boll rot than the stably yielding "normal" leaf cotton varieties. Okra leaves also allow evenly dispersed spray, higher flowering rates, and early maturing cotton plants.

The researchers infected okra-leaf plants with a modified virus that silenced the target gene, in order to determine if they have found the DNA sequence controlling leaf shape in cotton. Normal leaves were produced, until the plants overcame the virus and produced okra leaf shape again.

For more details, read the news releases from NC State and Donald Danforth Plant Science Center.

Figure: Cotton leaves come in different shapes, including what researchers call the "normal" shape (left) and "okra" shape (right).