Characterization and Expression Analysis of a Fiber Differentially Expressed Fasciclin-like Arabinogalactan Protein Gene in Sea Island Cotton Fibers

Abstract

Fasciclin-like arabinogalactan (FLA) protein is a cell-wall-associated protein playing crucial roles in regulating plant growth and development, and it was characterized in different plants including Upland cotton (Gossypium hirsutum L.). In cDNA-AFLP analysis of 25 DPA (days post anthesis) fiber mRNA, two FLA gene-related transcripts exhibit differential expression between Sea Island cotton ( G . barbadense L.) and Upland cotton. Based on the transcript-derived fragment, RACE-PCR and realtime PCR technique, GbFLA5 full-length cDNA was isolated and its expression profiles were characterized in both cotton plant tissues and secondary cell wall (SCW) fibers in this study. The 1154 bp GbFLA5 cDNA contains an ORF of 720 bp, encoding GbFLA5 protein of 239 amino acids residues in length with an estimated molecular mass of 25.41 kDa and isoelectric point of 8.63. The deduced GbFLA5 protein contains an N-terminal signal sequence, two AGP-like domains, a single fasciclin-like domain, and a GPI anchor signal sequence. Phylogenetic analysis shows that GbFLA5 protein is homologous to some known SCW-specific expressed FLAs of plant developing xylem, tension wood and cotton fibers. In the SCW deposition stage from 15 to 45 DPA detected, FLA5 maintains a significantly higher expression level in Sea Island cotton fibers than in Upland cotton fibers. The increasing FLA5 transcript abundance coincided with the SCW deposition process and the expression intensity differences coincided with their fiber strength differences between Sea Island cotton and Upland cotton. These expression profile features of GbFLA5 in cotton fibers revealed its tissue-specific and SCW developmental stage-specific expression characters. Further analysis suggested that GbFLA5 is a crucial SCW-specific protein which may contribute to fiber strength by affecting cellulose synthesis and microfibril deposition orientation.

Fascinating Fasciclins: A Surprisingly Widespread Family of Proteins that Mediate Interactions between the Cell Exterior and the Cell Surface

“…The majority of them are annotated as FLAs. The numbers of FLA encoding loci vary considerably between different plant genomes such as cotton ( 17 and 19 loci in Gossypium barbadense and G. hirsutum , respectively [ 69 , 70 ]), Eucalyptus grandis ( 18 [ 71 ]), Arabidopsis thaliana ( 21 [ 14 ]), Cannabis sativa ( 23 [ 72 ]), Brassica rapa ( 33 [ 73 ]), wheat Triticum aestivum ( 34 [ 51 ]), rice Oryza sativa ( 27 [ 74 ]) and cottonwood Populus trichocarpa ( 35 [ 75 ]). Apparently, diversity in this gene family varies even between closely related species (e.g., between the two Gossypium species or between Arabidopsis thaliana and Brassica rapa ).…”

“…Also in flax and hemp AtFla11/12 orthologs were highly expressed in fiber forming tissues [ 72 , 155 ]. A cotton AtFla12 ortholog was expressed at a higher level and for a longer time period in Gossypum barbadense compared to G. hirsutum correlating with greater fiber strength and length of the former [ 69 ]. Hence, AtFla11 orthologs might be natural genetic determinants for fiber crops.…”

The Arabidopsis thaliana FASCICLIN LIKE ARABINOGALACTAN PROTEIN 4 gene acts synergistically with abscisic acid signalling to control root growth

“…The biological roles of FLAs in plant growth and development follow the theme of an involvement in cell wall deposition. The Arabidopsis thaliana FLA11 and FLA12 genes are preferentially expressed in secondary cell wall- (SCW) forming cells ( Ito et al , 2005 ; Persson et al , 2005 ), similar to their orthologues from various other plant species ( Dahiya et al , 2006 ; MacMillan et al , 2010 ; Liu et al , 2013 ). Supporting a role in SCWs, the At-fla11/ At-fla12 double mutant displays a reduction in cellulose content accompanied by reduced tensile strength and tensile modulus of elasticity.…”

“…Indeed, there is accumulating evidence for FLAs to modulate signalling upstream of cell wall polymer biosynthesis. Overexpression of the cotton orthologue of At-FLA12, named Gh-FLA1 ( Liu et al , 2013 ), in transgenic cotton, results in an increased rate of fibre initiation and elongation and causes an upregulation of a suite of genes related to cell wall biosynthesis including other FLA genes, whereas antisense suppression has the opposite effect ( Huang et al , 2013 ). This gain-of-function phenotype shows that FLAs can control the transcriptional programme for cell wall formation, which is best explained by a function in signalling.…”

Idioblasts as pathways for distributing water absorbed by leaf surfaces to the mesophyll inCapparis odoratissima

“…Remarkably, works evaluating the compositon of the cell walls in the resurrection plant Craterostigma wilmsii , which completely losses water, regaining it thereafter, pointed to the hygroscopic properties of AGPs as critical players in this rapid and effective rehydration (Vicré et al, 2004). AGP-related proteins have been previously related with the tensile strength of stems due to their participation in secondary cell wall composition, such as in the vessels or fibers (Ito et al, 2005; Liu et al, 2013). But the presence of AGPs have never been reported before in idioblasts with such specific pattern as in the current work.…”