Comparative fiber property and transcriptome analyses reveal key genes potentially related to high fiber strength in cotton (Gossypium hirsutum L.) line MD52ne.

Md S. Islam,Yongliang Liu,Hee Jin Kim,David D. Fang,Chris D. Delhom,Gregory N. Thyssen

doi:10.1186/s12870-016-0727-2

Abstract

BackgroundIndividual fiber strength is an important quality attribute that greatly influences the strength of the yarn spun from cotton fibers. Fiber strength is usually measured from bundles of fibers due to the difficulty of reliably measuring strength from individual cotton fibers. However, bundle fiber strength (BFS) is not always correlated with yarn strength since it is affected by multiple fiber properties involved in fiber-to-fiber interactions within a bundle in addition to the individual fiber strength. Molecular mechanisms responsible for regulating individual fiber strength remain unknown. Gossypium hirsutum near isogenic lines (NILs), MD52ne and MD90ne showing variations in BFS provide an opportunity for dissecting the regulatory mechanisms involved in individual fiber strength.ResultsComprehensive fiber property analyses of the NILs revealed that the superior bundle strength of MD52ne fibers resulted from high individual fiber strength with minor contributions from greater fiber length. Comparative transcriptome analyses of the NILs showed that the superior bundle strength of MD52ne fibers was potentially related to two signaling pathways: one is ethylene and the interconnected phytohormonal pathways that are involved in cotton fiber elongation, and the other is receptor-like kinases (RLKs) signaling pathways that are involved in maintaining cell wall integrity. Multiple RLKs were differentially expressed in MD52ne fibers and localized in genomic regions encompassing the strength quantitative trait loci (QTLs). Several candidate genes involved in crystalline cellulose assembly were also up-regulated in MD52ne fibers while the secondary cell wall was produced.ConclusionComparative phenotypic and transcriptomic analyses revealed differential expressions of the genes involved in crystalline cellulose assembly, ethylene and RLK signaling pathways between the MD52ne and MD90ne developing fibers. Ethylene and its phytohormonal network might promote the elongation of MD52ne fibers and indirectly contribute to the bundle strength by potentially improving fiber-to-fiber interactions. RLKs that were suggested to mediate a coordination of cell elongation and SCW biosynthesis in other plants might be candidate genes for regulating cotton fiber cell wall assembly and strength.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0727-2) contains supplementary material, which is available to authorized users.

Highlights

Individual fiber strength is an important quality attribute that greatly influences the strength of the yarn spun from cotton fibers
Comparisons of bundle fiber properties between mature MD52ne and MD90ne fibers Fiber property analysis by high-volume instrument (HVI) showed that the bundle fiber strength (BFS) of mature MD52ne fibers was significantly greater (19 ~ 25 %) than that of MD90ne fibers grown in two separate fields that substantially differ in geographic location and environmental conditions (Table 1)
Correlation of bundle fiber strength with other fiber properties To determine how the BFS values of the Near-isogenic line (NIL) were affected by other physical properties involved in fiber-tofiber interactions, we developed an F2 population of 384 progeny plants derived from a cross between MD52ne and MD90ne

Summary

Introduction

Individual fiber strength is an important quality attribute that greatly influences the strength of the yarn spun from cotton fibers. Cotton (Gossypium spp.) fiber is the most important natural fiber in the textile industry [1] Physical properties such as strength, length, maturity (degree of thickness), and fineness determine the value and quality of cotton fibers and the yarn spun from them. During the past 2 decades, the fiber strength of US cotton has gradually improved through breeding [2], the pace of improvement is restricted by our limited knowledge of fiber strength development Both cotton producers and processers usually measure fiber strength from a bundle composed of thousands of individual fibers. The bundle fiber strength (BFS), which is called fiber tenacity, is measured by an automated high-volume instrument (HVI) designed to measure the market value of cotton fibers in efficient and rapid ways. High BFS (g/ tex) is obtained by either increasing the breaking force (g) or deceasing the fineness value (tex)

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