Heteromannan and Heteroxylan Cell Wall Polysaccharides Display Different Dynamics During the Elongation and Secondary Cell Wall Deposition Phases of Cotton Fiber Cell Development

Abstract

The roles of non-cellulosic polysaccharides in cotton fiber development are poorly understood. Combining glycan microarrays and in situ analyses with monoclonal antibodies, polysaccharide linkage analyses and transcript profiling, the occurrence of heteromannan and heteroxylan polysaccharides and related genes in developing and mature cotton (Gossypium spp.) fibers has been determined. Comparative analyses on cotton fibers at selected days post-anthesis indicate different temporal and spatial regulation of heteromannan and heteroxylan during fiber development. The LM21 heteromannan epitope was more abundant during the fiber elongation phase and localized mainly in the primary cell wall. In contrast, the AX1 heteroxylan epitope occurred at the transition phase and during secondary cell wall deposition, and localized in both the primary and the secondary cell walls of the cotton fiber. These developmental dynamics were supported by transcript profiling of biosynthetic genes. Whereas our data suggest a role for heteromannan in fiber elongation, heteroxylan is likely to be involved in the regulation of cellulose deposition of secondary cell walls. In addition, the relative abundance of these epitopes during fiber development varied between cotton lines with contrasting fiber characteristics from four species (G. hirsutum, G. barbadense, G. arboreum and G. herbaceum), suggesting that these non-cellulosic polysaccharides may be involved in determining final fiber quality and suitability for industrial processing.

The cotton (Gossypium hirsutum) NAC transcription factor (FSN1) as a positive regulator participates in controlling secondary cell wall biosynthesis and modification of fibers

“…Also, higher expressions of sucrose synthase, beta‐galactosidase ( BGAL ), beta‐D‐xylosidase ( BXL ), xyloglucan endotransglucosylase ( XET ), glucan endo‐1,3‐beta‐glucosidase ( BGL ) and phosphoenolpyruvate carboxykinase ( PEPC ) in fibers of the GhFSN1 OE transgenic cotton may be closely involved in the massive synthesis of cellulose. Previous studies also revealed that lignin and xylan are important components during the SCW deposition phase of cotton fiber development (Han et al ., ; Hernandez‐Gomez et al ., ). In this study, our transcriptome data revealed that xylan and lignin biosynthetic genes (such as homologs of AtIRX9/9‐L , AtIRX10/10‐L , AtIRX14/14‐L , AtGUX1‐3 and AtDUF579s and AtDUF231s ) were up‐regulated in the GhFSN1 OE transgenic fibers (Table S4).…”

Metabolism of polysaccharides in dynamic middle lamellae during cotton fibre development

“…Even though the fibres are made up largely of cellulose, other less abundant polysaccharides are important in ways that may be specific to cotton fibre cells. For example, developing cotton fibres transiently synthesise callose at the onset of secondary wall deposition (Maltby et al 1979) and Hernandez-Gomez et al (2015a) found xylan and cellulose transcript abundance to be tightly correlated during fiber development.…”

Structure of cellulose microfibrils in mature cotton fibres

“…Amongst the Gossypium genus, the species G. hirsutum, G. barbadense, G. arboreum and G. herbaceum have been domesticated for fibre production (Hernandez-Gomez et al, 2015). While G. hirsutum accounts for the majority of the cotton fibre production due to its high yield and wide environmental adaptability, G. barbadense presents superior fibre quality (i.e.…”