Expression Of Cell Wall-related Genes Research Articles

Suppression of cell wall-related genes associated with stunting of Oryza glaberrima infected with Rice tungro spherical virus.

Rice tungro disease is a complex disease caused by the interaction between Rice tungro bacilliform virus and Rice tungro spherical virus (RTSV). RTSV alone does not cause recognizable symptoms in most Asian rice (Oryza sativa) plants, whereas some African rice (O. glaberrima) plants were found to become stunted by RTSV. Stunting of rice plants by virus infections usually accompanies the suppression of various cell wall-related genes. The expression of cell wall-related genes was examined in O. glaberrima and O. sativa infected with RTSV to see the relationship between the severity of stunting and the suppression of cell wall-related genes by RTSV. The heights of four accessions of O. glaberrima were found to decline by 14–34% at 28 days post-inoculation (dpi) with RTSV, whereas the height reduction of O. sativa plants by RTSV was not significant. RTSV accumulated more in O. glaberrima plants than in O. sativa plants, but the level of RTSV accumulation was not correlated with the degree of height reduction among the four accessions of O. glaberrima. Examination for expression of genes for cellulose synthase A5 (CESA5) and A6 (CESA6), cellulose synthase-like A9 (CSLA9) and C7, and α-expansin 1 (expansin 1) and 15 precursors in O. glaberrima and O. sativa plants between 7 and 28 dpi with RTSV showed that the genes such as those for CESA5, CESA6, CSLA9, and expansin 1were more significantly suppressed in stunted plants of O. glaberrima at 14 dpi with RTSV than in O. sativa, suggesting that stunting of O. glaberrima might be associated with these cell wall-related genes suppressed by RTSV. Examination for expression of these genes in O. sativa plants infected with other rice viruses in previous studies indicated that the suppression of the expansin 1 gene is likely to be a signature response commonly associated with virus-induced stunting of Oryza species. These results suggest that stunting of O. glaberrima by RTSV infection might be associated with the suppression of these cell wall-related genes at the early stage of infection with RTSV.

Histone acetylation associated up-regulation of the cell wall related genes is involved in salt stress induced maize root swelling.

BackgroundSalt stress usually causes crop growth inhibition and yield decrease. Epigenetic regulation is involved in plant responses to environmental stimuli. The epigenetic regulation of the cell wall related genes associated with the salt-induced cellular response is still little known. This study aimed to analyze cell morphological alterations in maize roots as a consequence of excess salinity in relation to the transcriptional and epigenetic regulation of the cell wall related protein genes.ResultsIn this study, maize seedling roots got shorter and displayed swelling after exposure to 200 mM NaCl for 48 h and 96 h. Cytological observation showed that the growth inhibition of maize roots was due to the reduction in meristematic zone cell division activity and elongation zone cell production. The enlargement of the stele tissue and cortex cells contributed to root swelling in the elongation zone. The cell wall is thought to be the major control point for cell enlargement. Cell wall related proteins include xyloglucan endotransglucosylase (XET), expansins (EXP), and the plasma membrane proton pump (MHA). RT-PCR results displayed an up-regulation of cell wall related ZmEXPA1, ZmEXPA3, ZmEXPA5, ZmEXPB1, ZmEXPB2 and ZmXET1 genes and the down-regulation of cell wall related ZmEXPB4 and ZmMHA genes as the duration of exposure was increased. Histone acetylation is regulated by HATs, which are often correlated with gene activation. The expression of histone acetyltransferase genes ZmHATB and ZmGCN5 was increased after 200 mM NaCl treatment, accompanied by an increase in the global acetylation levels of histones H3K9 and H4K5. ChIP experiment showed that the up-regulation of the ZmEXPB2 and ZmXET1 genes was associated with the elevated H3K9 acetylation levels on the promoter regions and coding regions of these two genes.ConclusionsThese data suggested that the up-regulation of some cell wall related genes mediated cell enlargement to possibly mitigate the salinity-induced ionic toxicity, and different genes had specific function in response to salt stress. Histone modification as a mediator may contribute to rapid regulation of cell wall related gene expression, which reduces the damage of excess salinity to plants.

ABA may promote or delay peach fruit ripening through modulation of ripening- and hormone-related gene expression depending on the developmental stage

Peach (Prunus persica laevis L. Batsch) was chosen as a model to further clarify the physiological role of ABA during fruit ripening. To this aim, branches bearing one fruit at mid-S3, S3/S4 and S4 stages of fruit development and characterized by a different ripening index (I(AD)), as revealed by a non-destructive device called a DA-meter, were treated with ABA (0.02mM) for 1 and 5 days. Exogenously applied ABA interfered with the progression of ripening leading to less ripe or riper fruit depending on the physiological stage. To better understand the molecular basis of ABA interference with ripening, the time-course changes in the expression of ethylene-, cell wall-, and auxin-related genes as well as other genes (NCED, PIP, LOX, AOS and SOT) was evaluated in the fruit mesocarp. Real-time PCR analyses revealed that in mid-S3 fruit transcript levels of ethylene biosynthesis and signaling (ACS1, ACO1, ETR2, ERF2), cell wall softening-related (PG, PMEI, EXP1, EXP2) and auxin biosynthesis, conjugation, transport and perception (TRPB, IGPS, Aux/IAA, GH3, PIN1 and TIR1) genes were substantially down-regulated on day 5 indicating a ripening delay. On the contrary, in more advanced stages (S3/S4 and S4) the same genes were early (day 1) up-regulated suggesting an acceleration of ripening. Transcript profiling of other ripening-related genes revealed changes that were in accord with a ripening delay (mid-S3) or acceleration (S3/S4 and S4). Thus, in peach fruit, ABA appears to modulate ripening through interference not only with ethylene and cell wall but also with auxin-related genes.

Analysis of ripening-related gene expression in papaya using an Arabidopsis-based microarray

BackgroundPapaya (Carica papaya L.) is a commercially important crop that produces climacteric fruits with a soft and sweet pulp that contain a wide range of health promoting phytochemicals. Despite its importance, little is known about transcriptional modifications during papaya fruit ripening and their control. In this study we report the analysis of ripe papaya transcriptome by using a cross-species (XSpecies) microarray technique based on the phylogenetic proximity between papaya and Arabidopsis thaliana.ResultsPapaya transcriptome analyses resulted in the identification of 414 ripening-related genes with some having their expression validated by qPCR. The transcription profile was compared with that from ripening tomato and grape. There were many similarities between papaya and tomato especially with respect to the expression of genes encoding proteins involved in primary metabolism, regulation of transcription, biotic and abiotic stress and cell wall metabolism. XSpecies microarray data indicated that transcription factors (TFs) of the MADS-box, NAC and AP2/ERF gene families were involved in the control of papaya ripening and revealed that cell wall-related gene expression in papaya had similarities to the expression profiles seen in Arabidopsis during hypocotyl development.ConclusionThe cross-species array experiment identified a ripening-related set of genes in papaya allowing the comparison of transcription control between papaya and other fruit bearing taxa during the ripening process.

The GLABRA2 homeodomain protein directly regulates CESA5 and XTH17 gene expression in Arabidopsis roots

Arabidopsis root hair formation is determined by the patterning genes CAPRICE (CPC), GLABRA3 (GL3), WEREWOLF (WER) and GLABRA2 (GL2), but little is known about the later changes in cell wall material during root hair formation. A combined Fourier-transform infrared microspectroscopy-principal components analysis (FTIR-PCA) method was used to detect subtle differences in the cell wall material between wild-type and root hair mutants in Arabidopsis. Among several root hair mutants, only the gl2 mutation affected root cell wall polysaccharides. Five of the 10 genes encoding cellulose synthase (CESA1-10) and 4 of 33 xyloglucan endotransglucosylase (XTH1-33) genes in Arabidopsis are expressed in the root, but only CESA5 and XTH17 were affected by the gl2 mutation. The L1-box sequence located in the promoter region of these genes was recognized by the GL2 protein. These results indicate that GL2 directly regulates cell wall-related gene expression during root development.

Expression analysis of a set of genes related to the ripening of bananas and mangoes

During ripening many important physic-chemical changes contribute to fruit quality, and they are precisely determined by gene expression. Specific genes are essential to normal ripening; however, information on gene expression about the majority of tropical fruit, such as bananas and mangoes is limited. In this way, the present study was undertaken with the objective to provide preliminary access to the changes in expression of some genes potentially relevant to banana and mango ripening. To simultaneously evaluate the changes in gene expression, a small collection of genes related to ethylene biosynthesis, starch mobilization, cell wall disassembly, pigment synthesis and ascorbate metabolism was assembled in nylon membranes and probed with cDNA from unripe and ripe fruit. Some interesting differences were observed between gene expression in bananas and mangoes. In relation to starch metabolism, banana a-amylase was induced during ripening while phosphorylase was more induced in mangoes. Similarly, expression of cell wall-related genes for polygalacturonase and expansin were also different in those fruits. Fructanfructosyltransferase, chalcone synthase, and ascorbate oxidase genes were also induced in ripening mangoes, but not in bananas. Although the number of sequences involved was relatively small, this simple and feasible approach provided interesting preliminary data that can be starting points for more in depth studies.

Jasmonate-induced transcriptional changes suggest a negative interference with the ripening syndrome in peach fruit

Peach (Prunus persica L. Batsch) was chosen as a model to shed light on the physiological role of jasmonates (JAs) during fruit ripening. To this aim, the effects of methyl jasmonate (MJ, 0.40 mM) and propyl dihydrojasmonate (PDJ, 0.22 mM), applied in planta at different fruit developmental stages, on the time-course of ethylene production and fruit quality traits were evaluated. MJ-induced changes in fruit transcriptome at harvest and the expression profiling of relevant JA-responsive genes were analysed in control and JA-treated fruit. Exogenously applied JAs affected the onset of ripening depending upon the fruit developmental stage, with PDJ being more active than MJ. Both compounds enhanced the transcription of allene oxide synthase (PpAOS1), the first specific enzyme in the biosynthesis of jasmonic acid, and altered the pattern of jasmonic acid accumulation. Microarray transcriptome profiling showed that MJ down-regulated some ripening-related genes, such as 1-aminocyclopropane-1-carboxylic acid oxidase (PpACO1) and polygalacturonase (PG), and the transcriptional modulator IAA7. MJ also altered the expression of cell wall-related genes, namely pectate lyase (PL) and expansins (EXPs), and up-regulated several stress-related genes, including some of those involved in JA biosynthesis. Time-course expression profiles of PpACO1, PL, PG, PpExp1, and the transcription factor LIM confirmed the array results. Thus, in peach fruit, exogenous JAs led to a ripening delay due to an interference with ripening- and stress/defence-related genes, as reflected in the transcriptome of treated fruit at harvest.

The expression of several cell wall-related genes in Arabidopsis roots is down-regulated under boron deficiency

Plant cell wall is a dynamic structure that is of fundamental importance in plant growth and development, as well as in the response to environmental stresses. There is direct evidence for a role of boron (B) in cross-linking of cell wall rhamnogalacturonan II (RG-II) and pectin assembly, which shows that B is essential for cell wall structure and function. The aim of the present work was to investigate the effects of B deficiency on the expression of cell wall-related genes in Arabidopsis roots. For this purpose, plants were grown hydroponically in a nutrient solution supplemented with 2 μM B and then transferred to a boron-free medium for 6 and 24 h. A transcriptome analysis was carried out and several cell wall-related genes were identified, whose expressions were down-regulated by B deficiency. These genes belong to arabinogalactan protein, xyloglucan endotransglycosylase/hydrolase, polygalacturonase, pectate lyase, pectin methylesterase, expansin, and cellulose synthase-like gene families. These results suggest that in addition to the essential role that B plays in the structural organization of the cell wall, it could directly or indirectly have an impact on the expression levels of genes related to the cell wall.

MAIZEWALL. Database and developmental gene expression profiling of cell wall biosynthesis and assembly in maize.

An extensive search for maize (Zea mays) genes involved in cell wall biosynthesis and assembly has been performed and 735 sequences have been centralized in a database, MAIZEWALL (http://www.polebio.scsv.ups-tlse.fr/MAIZEWALL). MAIZEWALL contains a bioinformatic analysis for each entry and gene expression data that are accessible via a user-friendly interface. A maize cell wall macroarray composed of a gene-specific tag for each entry was also constructed to monitor global cell wall-related gene expression in different organs and during internode development. By using this macroarray, we identified sets of genes that exhibit organ and internode-stage preferential expression profiles. These data provide a comprehensive fingerprint of cell wall-related gene expression throughout the maize plant. Moreover, an in-depth examination of genes involved in lignin biosynthesis coupled to biochemical and cytological data from different organs and stages of internode development has also been undertaken. These results allow us to trace spatially and developmentally regulated, putative preferential routes of monolignol biosynthesis involving specific gene family members and suggest that, although all of the gene families of the currently accepted monolignol biosynthetic pathway are conserved in maize, there are subtle differences in family size and a high degree of complexity in spatial expression patterns. These differences are in keeping with the diversity of lignified cell types throughout the maize plant.

The use of microarray μPEACH1.0 to investigate transcriptome changes during transition from pre-climacteric to climacteric phase in peach fruit

The transition from pre-climacteric to climacteric phase is a critical step during fruit development. A holistic approach to study this transition has been undertaken using the first available peach microarray (μPEACH1.0) containing about 4800 oligonucleotide probes corresponding to a set of unigenes most of them expressed during the last stages of fruit development. Microarray hybridizations indicated that among the genes present in the microarray slide, 267 and 109 genes are up- and down-regulated, respectively. Genes have been classified according to the TAIR Gene Ontology into three main categories based on cellular localization, molecular function and biological process. Considering the cellular localization, the most significant up- and down-regulated gene products belong to cell wall and chloroplast compartments. Within the molecular function and biological process categories, a dramatic up-regulation has been detected for genes encoding transcription factors and enzymes involved in ethylene biosynthesis and action. A new member of ETR peach family ( Pp-ETR2) has been characterized: this gene shows high similarity to Arabidopsis EIN4, tomato Le-ETR4, and strawberry Fa-ETR2. Transition from S3 to S4 is paralleled by changes in expression of 19 genes encoding transcription factors (TFs) belonging to several families including MADS-box, AUX/IAA, bZIP, bHLH, HD, and Myb. Differential expression of genes involved in specific quality traits has also been observed: besides confirming previous data on cell wall-related gene expression, a new pectin-methyl esterase and two new expansins have been identified. Several genes encoding enzymes acting in the isoprenoid biosynthetic pathway appeared to be strongly induced at S3/S4 transition. Among those involved in carotenoid biosynthesis we found also a β-carotene hydroxylase, responsible for the formation of β-cryptoxanthin, the most abundant carotenoid of ripe yellow peaches.

The interaction of Slt2 MAP kinase with Knr4 is necessary for signalling through the cell wall integrity pathway in Saccharomyces cerevisiae.

In budding yeast, PKC1 plays an essential role in cell integrity and proliferation through a linear MAP (Mitogen Activated Protein) kinase phosphorylation cascade, which ends up with the activation of the Slt2-MAP kinase by dual phosphorylation on two conserved threonine and tyrosine residues. In this phosphorylated form, Slt2p kinase activates by phosphorylation at least two known downstream targets: Rlm1p, which is implicated in the expression of cell wall-related genes, and SBF, required for transcription activation of cell cycle-regulated genes at the G1 to S transition. In this paper, we demonstrate by two-hybrid, in vitro immunoprecipitation and tandem affinity purification (TAP) methods that Knr4p physically interacts with Slt2p. Moreover, we show that the absence of Knr4p alters proper signalling of Slt2p to its two known downstream targets. In a knr4 null mutant, the SLT2-dependent activation of Rlm1p is strongly reduced and the transcriptional activity of Rlm1p is decreased, although the phosphorylated form of Slt2p is more abundant than in wild-type cells. On the contrary, SBF is abnormally activated in this mutant, as shown by a more abundant phosphorylated form of Swi6p, by higher beta-galactosidase levels from a SCB-lacZ gene fusion, and by deregulation of the cyclic behaviour of several cell cycle-regulated genes. These results, taken together with our recent finding that Bck2p requires Knr4p to activate additively with Cln3-Cdc28p SBF target genes, lead to a model in which Knr4p is involved in co-ordinating the Slt2p-mediated cell wall integrity pathway with progression of the cell cycle.

Patterns of expression of cell wall related genes in sugarcane

Our search for genes related to cell wall metabolism in the sugarcane expressed sequence tag (SUCEST) database (<A HREF="http://sucest.lbi.dcc.unicamp.br/">http://sucest.lbi.dcc.unicamp.br</A>) resulted in 3,283 reads (1% of the total reads) which were grouped into 459 clusters (potential genes) with an average of 7.1 reads per cluster. To more clearly display our correlation coefficients, we constructed surface maps which we used to investigate the relationship between cell wall genes and the sugarcane tissues libraries from which they came. The only significant correlations that we found between cell wall genes and/or their expression within particular libraries were neutral or synergetic. Genes related to cellulose biosynthesis were from the CesA family, and were found to be the most abundant cell wall related genes in the SUCEST database. We found that the highest number of CesA reads came from the root and stem libraries. The genes with the greatest number of reads were those involved in cell wall hydrolases (e.g. beta-1,3-glucanases, xyloglucan endo-beta-transglycosylase, beta-glucosidase and endo-beta-mannanase). Correlation analyses by surface mapping revealed that the expression of genes related to biosynthesis seems to be associated with the hydrolysis of hemicelluloses, pectin hydrolases being mainly associated with xyloglucan hydrolases. The patterns of cell wall related gene expression in sugarcane based on the number of reads per cluster reflected quite well the expected physiological characteristics of the tissues. This is the first work to provide a general view on plant cell wall metabolism through the expression of related genes in almost all the tissues of a plant at the same time. For example, developing flowers behaved similarly to both meristematic tissues and leaf-root transition zone tissues. Besides providing a basis for future research on the mechanisms of plant development which involve the cell wall, our findings will provide valuable tools for plant engineering in the near future.