Cell adhesion in Arabidopsis thaliana is mediated by ECTOPICALLY PARTING CELLS 1--a glycosyltransferase (GT64) related to the animal exostosins.
ABSTRACT Despite the fact that several hundred glycosyltransferases have been identified from sequencing of plant genomes, the biological functions of only a handful have been established to date. A Poplar glycosyltransferase 64 (GT64) family member that is differentially expressed during the cell division and elongation phases of cambial growth was identified from previously generated transcript profiling of cambium tissues. The predicted Poplar GT64 protein has a closely related Arabidopsis homolog ECTOPICALLY PARTING CELLS (EPC1). Mutation of the EPC1 gene, one of three Arabidopsis GT64 family members, results in plants with a dramatically reduced growth habit, defects in vascular formation and reduced cell-cell adhesion properties in hypocotyl and cotyledon tissues. Secondary growth is enhanced in epc1 hypocotyl tissues and it is proposed that this results from the abnormal cell-cell adhesion within the cortical parenchyma cell layers. Loss of cell-cell contacts within cotyledon and leaf tissues is also proposed to account for vascular patterning defects and the fragile nature of epc1 tissues. The EPC1 protein thus plays a critical role during plant development in maintaining the integrity of organs via cell-cell adhesion, thereby providing mechanical strength and facilitating the movement of metabolites throughout the plant.
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ABSTRACT: Spike mosses are among the most basal vascular plants, and one species, Selaginella moellendorffii, was recently selected for full genome sequencing by the Joint Genome Institute (JGI). Glycosyltransferases (GTs) are involved in many aspects of a plant life, including cell wall biosynthesis, protein glycosylation, primary and secondary metabolism. Here, we present a comparative study of the S. moellendorffii genome across 92 GT families and an additional family (DUF266) likely to include GTs. The study encompasses the moss Physcomitrella patens, a non-vascular land plant, while rice and Arabidopsis represent commelinid and non-commelinid seed plants. Analysis of the subset of GT-families particularly relevant to cell wall polysaccharide biosynthesis was complemented by a detailed analysis of S. moellendorffii cell walls. The S. moellendorffii cell wall contains many of the same components as seed plant cell walls, but appears to differ somewhat in its detailed architecture. The S. moellendorffii genome encodes fewer GTs (287 GTs including DUF266s) than the reference genomes. In a few families, notably GT51 and GT78, S. moellendorffii GTs have no higher plant orthologs, but in most families S. moellendorffii GTs have clear orthologies with Arabidopsis and rice. A gene naming convention of GTs is proposed which takes orthologies and GT-family membership into account. The evolutionary significance of apparently modern and ancient traits in S. moellendorffii is discussed, as is its use as a reference organism for functional annotation of GTs.PLoS ONE 01/2012; 7(5):e35846. · 3.73 Impact Factor
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ABSTRACT: a b s t r a c t Verticillium wilt caused by the soil-borne fungus Verticillium dahliae (V. dahliae), is a devastating disease of cotton, leading to serious loss of lint yield worldwide. To study its resistance responses in both susceptible (Ejing No. 1) and resistant (NJ0703 and NJ0705) upland cotton cultivars (Gossypium hirsutum), cDNA-AFLP analysis was used to identify differentially expressed transcripts from resistant and susceptible cultivars that were infected with V. dahliae strain V991. A total of 83 transcript-derived fragments (TDFs) were obtained using 64 pairs of primer combinations. Interestingly, none of the differentially expressed fragments identified from susceptible cultivar Ejing No. 1 was found from resistant cultivars (NJ0703 and NJ0705). However, there were some similarities between NJ0703 (R) and NJ0705 (R), and 10 differentially expressed fragments were identified from both two resistant cultivars. The results indicated that the susceptible and resistant upland cottons responded differently to Verti-cillium infection. Moreover, the expression of transcripts was further validated through quantitative real-time PCR. Data showed that the activation of the transcripts was rapid and transient upon V. dahliae infection.Physiological and Molecular Plant Pathology 09/2012; 80:50-57. · 1.51 Impact Factor
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ABSTRACT: Pectin is a component of the cell walls of plants that is composed of acidic sugar-containing backbones with neutral sugar-containing side chains. It functions in cell adhesion and wall hydration, and pectin crosslinking influences wall porosity and plant morphogenesis. Despite its low abundance in the secondary cell walls that make up the majority of lignocellulosic biomass, recent results have indicated that pectin influences secondary wall formation in addition to its roles in primary wall biosynthesis and modification. This mini-review will examine these and other recent results in the context of biomass yield and digestibility and discuss how these traits might be enhanced by the genetic and molecular modification of pectin. The utility of pectin as a high-value, renewable biomass co-product will also be highlighted.Frontiers in Plant Science 01/2013; 4:67.