Integrated metabolomics and genomics analysis provides new insights into the fiber elongation process in Ligon lintless-2 mutant cotton (Gossypium hirsutum L.)

Marina Naoumkina,Rickie B Turley,David D Fang,Doug J Hinchliffe,John M Bland

doi:10.1186/1471-2164-14-155

Marina Naoumkina, Rickie B Turley + Show 3 more

Open Access

https://doi.org/10.1186/1471-2164-14-155

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Abstract

BackgroundThe length of cotton fiber is an important agronomic trait characteristic that directly affects the quality of yarn and fabric. The cotton (Gossypium hirsutum L.) fiber mutation, Ligon lintless-2, is controlled by a single dominant gene (Li2) and results in extremely shortened lint fibers on mature seeds with no visible pleiotropic effects on vegetative growth and development. The Li2 mutant phenotype provides an ideal model system to study fiber elongation. To understand metabolic processes involved in cotton fiber elongation, changes in metabolites and transcripts in the Li2 mutant fibers were compared to wild-type fibers during development.ResultsPrincipal component analysis of metabolites from GC-MS data separated Li2 mutant fiber samples from WT fiber samples at the WT elongation stage, indicating that the Li2 mutation altered the metabolome of the mutant fibers. The observed alterations in the Li2 metabolome included significant reductions in the levels of detected free sugars, sugar alcohols, sugar acids, and sugar phosphates. Biological processes associated with carbohydrate biosynthesis, cell wall loosening, and cytoskeleton were also down-regulated in Li2 fibers. Gamma-aminobutyric acid, known as a signaling factor in many organisms, was significantly elevated in mutant fibers. Higher accumulation of 2-ketoglutarate, succinate, and malate suggested higher nitrate assimilation in the Li2 line. Transcriptional activation of genes involved in nitrogen compound metabolism along with changes in the levels of nitrogen transport amino acids suggested re-direction of carbon flow into nitrogen metabolism in Li2 mutant fibers.ConclusionsThis report provides the first comprehensive analysis of metabolite and transcript changes in response to the Li2 mutation in elongating fibers. A number of factors associated with cell elongation found in this study will facilitate further research in understanding metabolic processes of cotton fiber elongation.

Highlights

The length of cotton fiber is an important agronomic trait characteristic that directly affects the quality of yarn and fabric
To further justify the use of the Li2 Near-isogenic line (NIL) and subsequent segregating populations as a model system to study cotton fiber elongation, the genetic similarity between the Li2 parental NILs was determined using SSR markers that were distributed across the entire Upland cotton genome
During the elongation stage (5–16 days post-anthesis (DPA)), WT samples were clearly separated from Li2 samples, indicating an alteration in the metabolome of the mutant fibers that corresponded with the loss of fiber elongation (Figure 2)

Summary

Introduction

The length of cotton fiber is an important agronomic trait characteristic that directly affects the quality of yarn and fabric. The cotton (Gossypium hirsutum L.) fiber mutation, Ligon lintless-2, is controlled by a single dominant gene (Li2) and results in extremely shortened lint fibers on mature seeds with no visible pleiotropic effects on vegetative growth and development. The length of the fiber is one of the most important characteristics and affects spinning efficiency and the quality of the resulting yarn [1]. Competition with synthetic fibers has forced cotton industry to invest heavily in research to develop higher-quality fibers; one of the major limitations in genetic improvement of fiber is the lack of information at the molecular level regarding genes and regulatory elements that control fiber development. Elucidating the cellular and molecular basis of fiber elongation could identify potential targets for genetic manipulation of fiber length

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