Cotton (Gossypium hirsutum) is an allotetraploid species. This makes mutants
difficult to generate by traditional approaches due to gene redundancy. The
team of Zhennan Zhang from the Institute of Microbiology of the Chinese
Academy of Science used the CTISPR-Cas9 system to confer fungal resistance
to cotton through editing of the Gh14-3-3d gene.
In T0 transgenic plants, several mutations at the expected target site were
detected in the allotetraploid cotton At or Dt subgenomes. These same
mutations were also found to be stably transmitted to the next generation.
These mutations in the At and Dt subgenomes also segregated in the T1
transgenic plants following Mendelian law.
Two homozygous Gh14-3-3d-edited transgene-free plants were chosen and
designated as ce1 and ce2. Both lines exhibited high resistance to
Verticillium dahliae infestation compared to the wildtype plants. These
transgene-free lines can be used as a germplasm to breed disease-resistant