Article

A High-Density Simple Sequence Repeat and Single Nucleotide Polymorphism Genetic Map of the Tetraploid Cotton Genome

G3-Genes Genomes Genetics (Impact Factor: 3.2). 01/2012; 2(1):43-58. DOI: 10.1534/g3.111.001552
Source: PubMed

ABSTRACT

Genetic linkage maps play fundamental roles in understanding genome structure, explaining genome formation events during evolution, and discovering the genetic bases of important traits. A high-density cotton (Gossypium spp.) genetic map was developed using representative sets of simple sequence repeat (SSR) and the first public set of single nucleotide polymorphism (SNP) markers to genotype 186 recombinant inbred lines (RILs) derived from an interspecific cross between Gossypium hirsutum L. (TM-1) and G. barbadense L. (3-79). The genetic map comprised 2072 loci (1825 SSRs and 247 SNPs) and covered 3380 centiMorgan (cM) of the cotton genome (AD) with an average marker interval of 1.63 cM. The allotetraploid cotton genome produced equivalent recombination frequencies in its two subgenomes (At and Dt). Of the 2072 loci, 1138 (54.9%) were mapped to 13 At-subgenome chromosomes, covering 1726.8 cM (51.1%), and 934 (45.1%) mapped to 13 Dt-subgenome chromosomes, covering 1653.1 cM (48.9%). The genetically smallest homeologous chromosome pair was Chr. 04 (A04) and 22 (D04), and the largest was Chr. 05 (A05) and 19 (D05). Duplicate loci between and within homeologous chromosomes were identified that facilitate investigations of chromosome translocations. The map augments evidence of reciprocal rearrangement between ancestral forms of Chr. 02 and 03 versus segmental homeologs 14 and 17 as centromeric regions show homeologous between Chr. 02 (A02) and 17 (D02), as well as between Chr. 03 (A03) and 14 (D03). This research represents an important foundation for studies on polyploid cottons, including germplasm characterization, gene discovery, and genome sequence assembly.

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    • "genome at a frequency of two markers per chromosome arm (Yu et al. 2012a). These markers were primarily identified on the basis of a uniform distribution across the 26 tetraploid cotton chromosomes (Wang et al. 2013; Blenda et al. 2012; Yu et al. 2012b; Zhao et al. 2012) with additional criteria including purported lack of locus duplication, PCR reproducibility, polymorphism information content (PIC), and source representation. These markers, many of which are single copy, were multiplexed prior to PCR to form 35 sets of reaction bins (Yu et al. 2012a). "
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    ABSTRACT: Key message A core marker set containing markers developed to be informative within a single commercial cotton species can elucidate diversity structure within a multi-species subset of the Gossypium germplasm collection. Abstract An understanding of the genetic diversity of cotton (Gossypium spp.) as represented in the US National Cotton Germplasm Collection is essential to develop strategies for collecting, conserving, and utilizing these germplasm resources. The US collection is one of the largest world collections and includes not only accessions with improved yield and fiber quality within cultivated species, but also accessions possessing sources of abiotic and biotic stress resistance often found in wild species. We evaluated the genetic diversity of a subset of 272 diploid and 1,984 tetraploid accessions in the collection (designated the Gossypium Diversity Reference Set) using a core set of 105 microsatellite markers. Utility of the core set of markers in differentiating intra-genome variation was much greater in commercial tetraploid genomes (99.7 % polymorphic bands) than in wild diploid genomes (72.7 % polymorphic bands), and may have been influenced by pre-selection of markers for effectiveness in the commercial species. Principal coordinate analyses revealed that the marker set differentiated interspecific variation among tetraploid species, but was only capable of partially differentiating among species and genomes of the wild diploids. Putative species-specific marker bands in G. hirsutum (73) and G. barbadense (81) were identified that could be used for qualitative identification of misclassifications, redundancies, and introgression within commercial tetraploid species. The results of this broad-scale molecular characterization are essential to the management and conservation of the collection and provide insight and guidance in the use of the collection by the cotton research community in their cotton improvement efforts.
    Full-text · Article · Jan 2015 · Theoretical and Applied Genetics
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    • "In addition, a significant number of polymorphic markers ([25 %) were from the two chromosomes 3 and 14. Target screening markers mapped in these two chromosomes revealed a much higher rate of Marker loci that were skewed from Mendelian segregation ratios were very common in both interspecific (Lacape et al. 2003; Yu et al. 2012; Yu et al. 2011) and intraspecific crosses (Chen et al. 2009; Shen et al. 2007; Ulloa et al. 2005) in cotton. In the present study, nearly half (43.63 %) of markers showed distorted segregation. "
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    ABSTRACT: Cotton fiber properties are very important to the yarn quality. Modern high-speed textile operations around the world require long, strong and fine cotton fibers. The objective of this research was to identify stable fiber quantitative trait loci (QTLs) that could be used in cotton breeding through marker-assisted selection (MAS). Two cotton lines, MD90ne and MD52ne, are near-isogenic with significant differences in fiber properties, especially strength. Fiber samples from 734 progeny plants of two F2 populations (A and B) derived from crosses between MD90ne and MD52ne were collected at Stoneville, MS, USA in 2012. Fiber quality attributes were measured using a High Volume Instrument 1000. A simple sequence repeat (SSR) genetic linkage map with 165 loci covering 632.53 cM was constructed using population A, consisting of 356 F2 individuals and used for identifying QTLs related to fiber bundle strength (FBS), short fiber index (SFI) and upper-half mean fiber length (UHML). One QTL for FBS originating from the stronger fiber parent MD52ne was identified on chromosome (Chr.) 3. Three QTLs each for SFI and UHML were identified on Chrs. 3, 4 and 14 and Chrs. 3, 11 and 24, respectively. Population B, consisting of 378 F2 progeny, was used to confirm these QTLs by analyzing 57 SSR markers mapped on Chrs. 3, 14 and 24. Three QTLs—qFBS-c3, qSFI-c14 and qUHML-c24—were confirmed and appeared stable. These three QTLs could potentially be used in breeding to improve cotton fiber quality through a MAS strategy.
    Full-text · Article · Aug 2014 · Molecular Breeding
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    • "RFLP markers reported by Rong et al. [32] were not screened due to unavailability of probes, and technical difficulties for RFLP marker analysis. The SSR markers mapped on Chr. 5 and its homeologous Chr.19 were also included because of a known translocation between Chr. 4 and Chr. 5 [45,46]. All together, a total of 921 SSR markers mapped in these four chromosomes were screened for polymorphism between DNA bulks. "
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    ABSTRACT: Background Cotton fiber length is very important to the quality of textiles. Understanding the genetics and physiology of cotton fiber elongation can provide valuable tools to the cotton industry by targeting genes or other molecules responsible for fiber elongation. Ligon Lintless-1 (Li1) is a monogenic mutant in Upland cotton (Gossypium hirsutum) which exhibits an early cessation of fiber elongation resulting in very short fibers (< 6 mm) at maturity. This presents an excellent model system for studying the underlying molecular and cellular processes involved with cotton fiber elongation. Previous reports have characterized Li1 at early cell wall elongation and during later secondary cell wall synthesis, however there has been very limited analysis of the transition period between these developmental time points. Results Physical and morphological measurements of the Li1 mutant fibers were conducted, including measurement of the cellulose content during development. Affymetrix microarrays were used to analyze transcript profiles at the critical developmental time points of 3 days post anthesis (DPA), the late elongation stage of 12 DPA and the early secondary cell wall synthesis stage of 16 DPA. The results indicated severe disruption to key hormonal and other pathways related to fiber development, especially pertaining to the transition stage from elongation to secondary cell wall synthesis. Gene Ontology enrichment analysis identified several key pathways at the transition stage that exhibited altered regulation. Genes involved in ethylene biosynthesis and primary cell wall rearrangement were affected, and a primary cell wall-related cellulose synthase was transcriptionally repressed. Linkage mapping using a population of 2,553 F2 individuals identified SSR markers associated with the Li1 genetic locus on chromosome 22. Linkage mapping in combination with utilizing the diploid G. raimondii genome sequences permitted additional analysis of the region containing the Li1 gene. Conclusions The early termination of fiber elongation in the Li1 mutant is likely controlled by an early upstream regulatory factor resulting in the altered regulation of hundreds of downstream genes. Several elongation-related genes that exhibited altered expression profiles in the Li1 mutant were identified. Molecular markers closely associated with the Li1 locus were developed. Results presented here will lay the foundation for further investigation of the genetic and molecular mechanisms of fiber elongation.
    Full-text · Article · Jun 2013 · BMC Genomics
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