Discovery and Identification of a Novel Ligon lintless-like Mutant (Lix) Similar to the Ligon lintless (Li1) in Allotetraploid Cotton

Structural Genomics

N/A

Cai, Caiping

Cai, Caiping

Mutants are a powerful resource for studying gene structure, function and evolution. In this present study, a novel Ligon lintless-like mutant (Lix), that has short fibers and deformed leaves and stems, was bred from the progeny of transgenic cottons. The Lix mutant is similar in morphology to the Ligon lintless (Li1) mutant. Genetic analysis and molecular mapping were performed for the Lix and Li1 mutants. These two mutants are monogenic dominant mutants with distorted growth of vegetative and reproductive structures. Seedlings of the dominant homozygote Li1Li1 genotype are lethal, while LixLix plants are viable but show no reproductive growth. Molecular tagging showed that the Lix gene is located on Chr. 04 in a 30.9 cM region, with the closest markers flanking Lix being NAU8376 and NAU3469 (at 6.4 and 24.5 cM, respectively). In a previous study, the Li1 gene was mapped to Chr. 22, and Chr. 04 and Chr. 22 are homoeologous chromosomes in tetraploid cotton. Combined the phenotype of the novel Lix mutant similar to Li1 with molecular mapping analysis, we supposed that Lix in the Lix mutant and Li1 in the Li1 mutant be duplicated genes. The identification and genetic mapping of Lix/Li1 genes using mutants provides a foundation for isolating these genes. In turn, this will permit studies to elucidate the functional and evolutionary roles for these genes in cotton growth and development, which will also reveal the relationship between the deformed plant morphologies and polar auxin transport in allotetraploid cotton.