Comparative Proteomics Indicates That Biosynthesis of Pectic Precursors Is Important for Cotton Fiber and Arabidopsis Root Hair Elongation

Abstract

The quality of cotton fiber is determined by its final length and strength, which is a function of primary and secondary cell wall deposition. Using a comparative proteomics approach, we identified 104 proteins from cotton ovules 10 days postanthesis with 93 preferentially accumulated in the wild type and 11 accumulated in the fuzzless-lintless mutant. Bioinformatics analysis indicated that nucleotide sugar metabolism was the most significantly upregulated biochemical process during fiber elongation. Seven protein spots potentially involved in pectic cell wall polysaccharide biosynthesis were specifically accumulated in wild-type samples at both the protein and transcript levels. Protein and mRNA expression of these genes increased when either ethylene or lignoceric acid (C24:0) was added to the culture medium, suggesting that these compounds may promote fiber elongation by modulating the production of cell wall polymers. Quantitative analysis revealed that fiber primary cell walls contained significantly higher amounts of pectin, whereas more hemicellulose was found in ovule samples. Significant fiber growth was observed when UDP-L-rhamnose, UDP-D-galacturonic acid, or UDP-D-glucuronic acid, all of which were readily incorporated into the pectin fraction of cell wall preparations, was added to the ovule culture medium. The short root hairs of Arabidopsis uer1-1 and gae6-1 mutants were complemented either by genetic transformation of the respective cotton cDNA or by adding a specific pectin precursor to the growth medium. Cell elongation and expansion contribute significantly to the growth and morphogenesis of higher plants. Cotton (Gossypium hirsutum) fibers are single cells that differentiate from the outer integuments of the ovule. Cotton lint (the industrial name for fiber) is the most prevalent natural raw material used in the textile industry, so its production plays a significant role in the global economy. The number of fibers present on each ovule (cotton productivity), the final length, and the strength of each fiber (fiber quality) are determined by four separable biological processes: fiber initiation, elongation (primary cell wall synthesis), cell wall thickening (secondary cell wall deposition), and maturation. The fiber initiation stage occurs from 3 days prior to anthesis to 3 days postanthesis (dpa) 1 and is characterized by the enlargement and protrusion of epidermal cells from the ovule surface. During the fiber elongation period (5-25 dpa), cells demonstrate vigorous expansion with peak growth rates of Ͼ2 mm/day until the fibers reach their final dimensions (1-3). In the secondary cell wall deposition phase

A Fasciclin-Like Arabinogalactan Protein, GhFLA1, Is Involved in Fiber Initiation and Elongation of Cotton

“…Pectin is an important constituent in the cell wall. It may account for 30% of the total sugar content in fiber cells but less than 18% in 10-DPA ovules (Pang et al, 2010). In our study, the expression of several GhFLAs and other genes related to hemicellulose and cellulose biosynthesis was dramatically up-regulated in fibers of GhFLA1 overexpression transgenic cotton plants but down-regulated in GhFLA1 RNAi transgenic lines.…”

“…All cell wall fractions were subjected to 2 M trifluoroacetic acid at 120°C for 2 h to produce neutral monosaccharides and subsequent derivatization of the solubilized monosaccharides into their corresponding alditol acetates. Finally, the different fractions were run on a gas chromatograph (6890N; Agilent Technologies) with nitrogen as the carrier gas to determine their sugar composition by the method described previously (Pang et al, 2010).…”

Parallel up-regulation of the profilin gene family following independent domestication of diploid and allopolyploid cotton ( Gossypium )

“…For example, in cultivated G. hirsutum, each of the five genes GPRF1-GPRF5 contributes substantially and relatively equitably to the total profilin transcriptome (18,29,21,10, and 22%, respectively), whereas in the wild form of the same species, there is more variation among genes (1,23,28,19, and 29%, respectively; Fig. 2D).…”

“…Profilin has been shown to affect tip growth in moss, root hairs, pollen tubes, and cotton fiber (15,(27)(28)(29). Profilin is expressed during early cotton fiber development (14,15), and on the basis of the observation that overexpression in transgenic tobacco cells produced elongated cells with thicker and longer microfilament cables, Wang et al (15) suggested that profilin plays a role in the rapid elongation of cotton fibers by promoting actin polymerization.…”

Proteomic and Virus-induced Gene Silencing (VIGS) Analyses Reveal That Gossypol, Brassinosteroids, and Jasmonic acid Contribute to the Resistance of Cotton to Verticillium dahliae

“…Protein Extraction and 2D Electrophoresis-For 2D-PAGE, proteins from cotton roots were prepared according to Yao and Pan (32,33) with minor modifications. Frozen root tissues were ground in liquid nitrogen to a fine powder and incubated in extraction buffer (Ϫ20°C precooled acetone, 12% w/v trichloroacetic acid, and 0.07% w/v dithiothreitol (DTT)).…”