Discovery and identification of a novel Ligon lintless-like mutant (Lix) similar to the Ligon lintless (Li1) in allotetraploid cotton

Abstract

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 isolated 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 Li 1 Li 1 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 spanned by NAU8376 and NAU3469. In a previous study, the Li 1 gene was mapped to Chr. 22, and Chr. 04 and Chr. 22 are homoelogous chromosomes in tetraploid cotton. So, we propose that Lix and Li1 mutants have similar mutated morphology, and Lix is mapped to a homoelogous chromosome carrying Li 1 . The identification and genetic mapping of Lix/Li 1 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.

Quantitative trait loci analysis of fiber quality traits using a random-mated recombinant inbred population in Upland cotton (Gossypium hirsutum L.)

“…Recently, Gore et al [46] observed the same phenomenon when using RILs derived from a cross between TM-1 and NM24016. In our previous research to fine map the Ligon-lintless 1 ( Li 1 ) gene, we revealed a similar phenomenon [51], and so did Cai et al [52]. Chr.15 had a very big gap (80.47 cM) at the end of its long arm.…”

Transcript profiling by microarray and marker analysis of the short cotton (Gossypium hirsutum L.) fiber mutant Ligon lintless-1 (Li 1 )

“…This result may also imply that the genomic region harboring Li 1 locus is highly monomorphic. Recently, Cai et al [20] reported a similar phenomenon when mapping the Lix locus. One of their flanking markers, NAU3469, was 24.5 cM away from the Lix locus.…”

“…Mutant lines exhibiting very short seed fibers include the Ligon Lintless-1 and −2 lines ( Li 1 and Li 2 ) [18,19]. Recently, Cai et al [20] analyzed a man-made mutant Lix that showed similar phenotype to Li 1 . The understanding that initiation, elongation, and secondary cell wall synthesis are distinct developmental processes often leads to the utilization of the applicable mutant to study the specific process of interest.…”

Genetic fine mapping and candidate gene analysis of the Gossypium hirsutum Ligon lintless-1 (Li1) mutant on chromosome 22(D)

“…Cotton fiber mutants can be divided into three categories: fiberless seeds (such as Fbl and Sma-4(ha)), seeds with very shortlint fiber (such as Li1, Li2, and Lix) (Cai et al 2013;Karaca et al 2002;Kohel et al 1992), and fuzzless seeds with lint fiber (such as N1, sma-4 (fz), n2, xu142, and more than 100 recently reported naked mutants) (Rong et al 2005;Sun et al 2012;Turley and Kloth 2002). Because a single gene mutation in some of these mutants can affect the initiation and development of cotton fibers (Rong et al 2005;Sun et al 2012;Kohel et al 2002;Turley and Kloth 2008;Turley et al 2007), the isolation of these genes is critical to elucidate the molecular basis of cotton fiber development.…”

“…Recently, a mutant with a similar phenotype controlled by a dominant gene was created and mapped to a region of chromosome (Chr.) 04(A), which was thought to be homoeologous to the region of Li1 on Chr.22(D) (Cai et al 2013). Because the Li1 mutant is a model for studying fiber elongation and both primary and secondary cell wall thickening processes, several groups have comprehensively explored gene alterations in the Li1 mutant.…”