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1.
Xyloglucan endotransglycosylase/hydrolases (XTHs) are believed to modify the cell wall structure by cleaving a xyloglucan
polymer and transferring the newly generated, potentially reducing, terminal to another xyloglucan. We report here the detailed
analysis of 37 Populus trichocarpa XTH genes/proteins in their divergence in both the coding and 5′ promoter regions. Our results show that the Populus XTH genes have experienced whole-genome and local duplications and pre- and post-speciation divergence. Genome-wide and segmental
duplications seem to be dominant in subfamily I and III, while tandem duplication seems to be the major mechanism for the
subfamily II expansion, which also has higher average ratios of K
a/ K
s compared to those in subfamily I and III. There was a general lack of organ-specific gene expression. In contrast, the expression
patterns in subfamily II varied in response to various hormone treatments, with II-A being up-regulated and II-B down-regulated
after 2 h of hormone treatment. Expression for this subfamily was verified using the 1.5-kb PtXTH22 promoter that was fused
with the GUS reporter gene and transformed into Arabidopsis. The PtXTH22 promoter contains auxin response element, ethylene insensitive 3-like factors, and brassinosteroid response
cis-elements. Histochemical GUS staining of transgenic Arabidopsis seedlings confirmed that the PtXTH22 promoter was up-regulated by several hormones. 相似文献
5.
Glycosyltransferase family14 (GT14) belongs to the glycosyltransferase (GT) superfamily that plays important roles in the biosynthesis of cell walls, the most abundant source of cellulosic biomass for bioethanol production. It has been hypothesized that DUF266 proteins are a new class of GTs related to GT14. In this study, we identified 62 GT14 and 106 DUF266 genes (named GT14-like herein) in Arabidopsis, Oryza, Populus, Sorghum and Vitis. Our phylogenetic analysis separated GT14 and GT14-like genes into two distinct clades, which were further divided into eight and five groups, respectively. Similarities in protein domain, 3D structure and gene expression were uncovered between the two phylogenetic clades, supporting the hypothesis that GT14 and GT14-like genes belong to one family. Therefore, we proposed a new family name, GT14/GT14-like family that combines both subfamilies. Variation in gene expression and protein subcellular localization within the GT14-like subfamily were greater than those within the GT14 subfamily. One-half of the Arabidopsis and Populus GT14/GT14-like genes were found to be preferentially expressed in stem/xylem, indicating that they are likely involved in cell wall biosynthesis. This study provided new insights into the evolution and functional diversification of the GT14/GT14-like family genes. 相似文献
8.
Sucrose synthase is a key enzyme in sucrose metabolism in plant cells, and it is involved in the synthesis of cell wall cellulose.
Although the sucrose synthase gene ( SUS) family in the model plants Arabidopsis thaliana has been characterized, little is known about this gene family in trees. This study reports the identification of two novel
SUS genes in the economically important poplar tree. These genes were expressed predominantly in mature xylem. Using molecular
cloning and bioinformatics analysis of the Populus genome, we demonstrated that SUS is a multigene family with seven members that each exhibit distinct but partially overlapping expression patterns. Of particular
interest, three SUS genes were preferentially expressed in the stem xylem, suggesting that poplar SUSs are involved in the formation of the secondary cell wall. Gene structural and phylogenetic analyses revealed that the Populus SUS family is composed of four main subgroups that arose before the separation of monocots and dicots. Phylogenetic analyses
associated with the tissue- and organ-specific expression patterns. The high intraspecific nucleotide diversity of two SUS genes was detected in the natural population, and the π
nonsyn/ π
syn ratio was significantly less than 1; therefore, SUS genes appear to be evolving in Populus, primarily under purifying selection. This is the first comprehensive study of the SUS gene family in woody plants; the analysis includes genome organization, gene structure, and phylogeny across land plant lineages,
as well as expression profiling in Populus. 相似文献
10.
Summary. Expression profiles of genes involved in cell wall metabolism and water transport were compared with changes in grape ( Vitis vinifera L.) berry growth, basic chemical composition, and the shape, size, and wall thickness of cells within tissues of the berry
pericarp. Expression of cell wall-modifying and aquaporin genes in berry pericarp tissues generally followed a bimodal expression
profile with high levels of expression coinciding with the two periods of rapid berry growth, stages I and III, and low levels
of expression corresponding to the slow-growth period, stage II. Cellular expansion was observed throughout all tissues during
stage I, and only mesocarp cellular expansion was observed during stage III. Expansion of only exocarp cells was evident during
transition between stages II and III. Cell wall-modifying and aquaporin gene expression profiles followed similar trends in
exocarp and mesocarp tissues throughout berry development, with the exception of the up-regulation of pectin methylesterase,
pectate lyase, two aquaporin genes ( AQ1 and AQ2), and two expansin genes ( EXP3 and EXPL) during stage II, which was delayed in the exocarp tissue compared with mesocarp tissue. Exocarp endo-(1→3)-β-glucanase and
expansin-like gene expression was concurrent with increases in epidermal and hypodermal cell wall thickness. These results
indicate a potential role of the grape berry skin in modulating grape berry growth.
Correspondence: P. Bowen, Pacific Agri-Food Research Centre, 4200
Highway 97, Summerland, BC V0H 1Z0, Canada 相似文献
11.
Despite the availability of the Populus genome sequence and the development of genetic, genomic, and transgenic approaches for its improvement, the lengthy life span of Populus and the cumbersome process required for its transformation have impeded rapid characterization of gene functions in Populus. Protoplasts provide a versatile and physiologically relevant cell system for high-throughput analysis and functional characterization of plant genes. Here, a highly efficient transient expression system using Populus mesophyll protoplasts was developed based on the following three steps. The first step involved formulating a new enzyme cocktail containing 2 % Cellulase C2605 and 0.5 % Pectinase P2611, which was shown to enable efficient large-scale isolation of homogenous Populus mesophyll protoplasts. The second step involved optimization of transfection conditions, such as the polyethylene glycol concentration and amount of plasmid DNA to ensure a >80 % transfection efficiency for Populus protoplasts. The third step involved using the Populus protoplast transient expression system to successfully determine the subcellular localizations of proteins, emulate signaling events during pathogen infection, and prepare protein extracts for Western blotting and protein–protein interaction assays. This rapid and highly efficient transient gene expression system in Populus mesophyll protoplasts will facilitate the rapid identification of gene functions and elucidation of signaling pathways in Populus. 相似文献
12.
Carotenoids, important lipid-soluble antioxidants in photosynthetic tissues, are known to be completely absent in rice endosperm.
Many studies, involving transgenic manipulations of carotenoid biosynthesis genes, have been performed to get carotenoid-enriched
rice grain. Study of genes involved in their biosynthesis can provide further information regarding the abundance/absence
of carotenoids in different tissues. We have identified 16 and 34 carotenoid biosynthesis genes in rice and Populus genomes, respectively. A detailed analysis of the domain structure of carotenoid biosynthesis enzymes in rice, Populus and Arabidopsis has shown that highly conserved catalytic domains, along with other domains, are present in these proteins. Phylogenetic
analysis of rice genes with Arabidopsis and other characterized carotenoid biosynthesis genes has revealed that homologous genes exist in these plants, and the duplicated
gene copies probably adopt new functions. Expression of rice and Populus genes has been analyzed by full-length cDNA- and EST-based expression profiling. In rice, this analysis was complemented
by real-time PCR, microarray and signature-based expression profiling, which reveal that carotenoid biosynthesis genes are
highly expressed in light-grown tissues, have differential expression pattern during vegetative/reproductive development and
are responsive to stress. 相似文献
15.
Glutamate dehydrogenases (GDH, EC 1.4.1.2~4) are ubiquitous enzymes encoded by GDH genes. So far, at least two GDH members have been characterized in plants, but most members of this family in rice remains to be characterized. Here, we
show that four putative GDH genes ( OsGDH1-4) are present in the rice genome. The GDH sequences from rice and other species can be classified into two types (I and II).
OsGDH1-3 belonged to type II genes, whereas OsGDH4 belonged to type I like gene. Our data implied that the expansion rate of type I genes was much slower than that of type
II genes and species-specific expansion contributed to the evolution of type II genes in plants. The expression levels of
the different members of GDH family in rice were evaluated using quantitative real-time PCR and microarray analysis. Gene expression patterns revealed
that OsGDH1, OsGDH2, and OsGDH4 are expressed ubiquitously in various tissues, whereas OsGDH3 expression is glumes and stamens specific. The expression of the OsGDH family members responded differentially to nitrogen and phosphorus-deprivation, indicating their roles under such stress
conditions. Implications of the expression patterns with respect to the functions of these genes were discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
TALE (three-amino acid loop extension)转录因子在植物生长发育及细胞分化过程中起重要作用.在多种植物中均已鉴定出TALE转录因子的家族成员,但是萝卜TALE转录因子家族的研究鲜有报道.文中通过生物信息学手段在象牙白萝卜全基因组中鉴定出了分布于9条染色体上的33个TALE家族基因.研究... 相似文献
17.
Like many plants, Populus has an evolutionary history in which several, both recent and more ancient, genome duplication events have occurred and,
therefore, constitutes an excellent model system for studying the functional evolution of genes. In the present study, we
have focused on the properties of genes with tissue-specific differential expression patterns in poplar. We identified the
genes by analyzing digital expression profiles derived by mapping 90,000+ expressed sequence tags (ESTs) from 18 sources to
the predicted genes of Populus. Our sequence analysis suggests that tissue-specific differentially expressed genes have less diverged paralogs than average,
indicating that gene duplication events is an important event in the pathway leading to this type of expression pattern. The
functional analysis showed that genes coding for proteins involved in processes of functional importance for the specific
tissue(s) in which they are expressed and genes coding for regulatory or responsive proteins are most common among the differentially
expressed genes, demonstrating that the expression differentiation process is under strong selective pressure. Thus, our data
supports a model where gene duplication followed by gene specialization or expansion of the regulatory and responsive networks
leads to tissue-specific differential expression patterns. We have also searched for clustering of genes with similar expression
pattern into gene-expression neighborhoods within the Populus genome. However, we could not detect any major clustering among the analyzed genes with highly specific expression patterns.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
18.
[背景]激发子(elicitin)是卵菌(Oomycetes)疫霉和腐霉分泌的可诱发宿主产生免疫反应的小分子化合物.[目的]鉴定紫菜腐霉激发子基因家族,分析其结构特征和在感染宿主过程中可能的作用机制.[方法]运用同源比对法筛查紫菜腐霉NBRC33253基因组中激发子基因家族成员,利用生物信息学工具分析激发子家族的理化性... 相似文献
20.
The wall-associated kinase (WAK) gene family, a subfamily of the receptor-like kinase (RLK) gene family, is associated with the cell wall in plants, and has vital functions in cell expansion, pathogen resistance, and heavy metal stress tolerance because of their roles of the extracellular environment sensors to trigger intracellular signals in Arabidopsis. In the present study, 96 Chinese cabbage (Brassica rapa ssp. pekinensis) BrWAK gene family members were identified from the B. rapa genome using a reiterative database search and manual confirmation. The protein domain characterization, gene structure analysis, and phylogenetic analysis of the BrWAKs classified them into three gene groups. Comparative genomic analysis between WAK genes from Chinese cabbage and Arabidopsis revealed that the BrWAK genes have undergone the gene expansion and deletion events during evolution. Furthermore, the conserved motifs in the kinase domains of the WAK proteins and eukaryotic protein kinase family proteins were compared and some non-RD kinase proteins among the BrWAKs were identified. Ultimately, expression analysis of BrWAK genes in six tissues and under various stress conditions revealed that some tissue-specific WAK genes might function in callus cell growth and reproduction process; Bra012273, Bra016426, Bra016427, and Bra025882 might be involved in downy mildew resistance and high humidity stress; Bra012273, Bra025882, and Bra025883 might be responded to drought and heat stress. Taken together, this research was identified and classified the WAK gene family in Chinese cabbage and provided valuable resources to explore the potential roles of BrWAK genes in plant development and stress responses. 相似文献
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