The Experts below are selected from a list of 5739 Experts worldwide ranked by ideXlab platform
Daniel J. Cosgrove - One of the best experts on this subject based on the ideXlab platform.
-
global cellulose biomass horizontal gene transfers and domain fusions drive microbial expansin evolution
New Phytologist, 2020Co-Authors: William R Chase, Daniel J. Cosgrove, Olga Zhaxybayeva, Jorge Rocha, Lori R ShapiroAbstract:: Plants must rearrange the network of complex carbohydrates in their cell walls during normal growth and development. To accomplish this, all plants depend on proteins called Expansins that nonenzymatically loosen noncovalent bonding between cellulose microfibrils. Surprisingly, expansin genes have more recently been found in some bacteria and microbial eukaryotes, where their biological functions are largely unknown. Here, we reconstruct a comprehensive phylogeny of microbial expansin genes. We find these genes in all eukaryotic microorganisms that have structural cell wall cellulose, suggesting Expansins evolved in ancient marine microorganisms long before the evolution of land plants. We also find Expansins in an unexpectedly high diversity of bacteria and fungi that do not have cellulosic cell walls. These bacteria and fungi inhabit varied ecological contexts, mirroring the diversity of terrestrial and aquatic niches where plant and/or algal cellulosic cell walls are present. The microbial expansin phylogeny shows evidence of multiple horizontal gene transfer events within and between bacterial and eukaryotic microbial lineages, which may in part underlie their unusually broad phylogenetic distribution. Overall, Expansins are unexpectedly widespread in bacteria and eukaryotes, and the contribution of these genes to microbial ecological interactions with plants and algae has probbaly been underappreciated.
-
expansin gene loss is a common occurrence during adaptation to an aquatic environment
Plant Journal, 2020Co-Authors: Nathan K. Hepler, Robert E. Carey, Alexa Bowman, Daniel J. CosgroveAbstract:Expansins comprise a superfamily of plant cell wall loosening proteins that can be divided into four individual families (EXPA, EXPB, EXLA and EXLB). Aside from inferred roles in a variety of plant growth and developmental traits, little is known regarding the function of specific expansin clades, for which there are at least 16 in flowering plants (angiosperms); however, there is evidence to suggest that some Expansins have cell-specific functions, in root hair and pollen tube development, for example. Recently, two duckweed genomes have been sequenced (Spirodela polyrhiza strains 7498 and 9509), revealing significantly reduced superfamily sizes. We hypothesized that there would be a correlation between expansin loss and morphological reductions seen among highly adapted aquatic species. In order to provide an answer to this question, we characterized the expansin superfamilies of the greater duckweed Spirodela, the marine eelgrass Zostera marina and the bladderwort Utricularia gibba. We discovered rampant expansin gene and clade loss among the three, including a complete absence of the EXLB family and EXPA-VII. The most convincing correlation between morphological reduction and expansin loss was seen for Utricularia and Spirodela, which both lack root hairs and the root hair expansin clade EXPA-X. Contrary to the pattern observed in other species, four Utricularia Expansins failed to branch within any clade, suggesting that they may be the result of neofunctionalization. Last, an expansin clade previously discovered only in eudicots was identified in Spirodela, allowing us to conclude that the last common ancestor of monocots and eudicots contained a minimum of 17 Expansins.
-
from morphogenesis to pathogenesis a cellulose loosening protein is one of the most widely distributed tools in nature
bioRxiv, 2019Co-Authors: William R Chase, Daniel J. Cosgrove, Olga Zhaxybayeva, Jorge Rocha, Lori R ShapiroAbstract:Abstract Plants must rearrange the network of complex carbohydrates in their cell walls during normal growth and development. To accomplish this, all plants depend on proteins called Expansins that non-enzymatically loosen hydrogen bonds between cellulose microfibrils. Because of their key role in cell wall extension during growth, expansin genes are ubiquitous, diverse, and abundant throughout all land plants. Surprisingly, expansin genes have more recently been found in some bacteria and microbial eukaryotes, where their biological functions are largely unknown. Here, we reconstruct the phylogeny of microbial expansin genes. We find these genes in all eukaryotic microorganisms that have structural cellulose in their cell walls, suggesting Expansins evolved in ancient marine microorganisms long before the evolution of land plants. We also find Expansins in an unexpectedly high phylogenetic diversity of bacteria and fungi that do not have cellulosic cell walls. These bacteria and fungi with expansin genes inhabit varied ecological contexts mirroring the diversity of terrestrial and aquatic niches where plant and/or algal cellulosic cell walls are present. The microbial expansin phylogeny shows evidence of multiple horizontal gene transfer events within and between bacterial and eukaryotic microbial lineages, which may in part underlie their unusually broad phylogenetic distribution. Taken together, we find Expansins to be unexpectedly widespread in both bacterial and eukaryotic genetic backgrounds, and that the contribution of these genes to bacterial and fungal ecological interactions with plants and algae has likely been underappreciated. Importance Cellulose is the most abundant biopolymer on earth. In plant cell walls, where most global cellulose biomass is found, cellulose microfibrils occur intertwined with hemicelluloses and pectins. The rigidity of this polysaccharide matrix provides plant cell walls with structural support, but this rigidity also restricts cellular growth and development. Irreversible, non-enzymatic loosening of structural carbohydrates by expansin proteins is key to successful cell wall growth in plants and green algae. Here, we find that expansin genes are distributed far more broadly throughout diverse bacterial and fungal lineages lacking cellulosic cell walls than previously known. Multiple horizontal gene transfer events are in part responsible for their unusually wide phylogenetic distribution. Together, these results suggest that in addition to being the key evolutionary innovation by which eukaryotes remodel structural cellulose in their cell walls, Expansins likely have remarkably broad and under-recognized utility for microbial species that interact with plant and algal structural cellulose in diverse ecological contexts.
-
measuring the biomechanical loosening action of bacterial Expansins on paper and plant cell walls
Methods of Molecular Biology, 2017Co-Authors: Daniel J. Cosgrove, Nathan K. Hepler, Edward R Wagner, Daniel M DurachkoAbstract:Expansins are proteins that loosen plant cell walls but lack enzymatic activity. Here, we describe two protocols tailored to measure the biomechanical activity of bacterial expansin. The first assay relies on weakening of filter paper by expansin. The second assay is based on induction of creep (long-term, irreversible extension) of plant cell wall samples.
-
plant Expansins diversity and interactions with plant cell walls
Current Opinion in Plant Biology, 2015Co-Authors: Daniel J. CosgroveAbstract:Expansins were discovered two decades ago as cell wall proteins that mediate acid-induced growth by catalyzing loosening of plant cell walls without lysis of wall polymers. In the interim our understanding of Expansins has gotten more complex through bioinformatic analysis of expansin distribution and evolution, as well as through expression analysis, dissection of the upstream transcription factors regulating expression, and identification of additional classes of expansin by sequence and structural similarities. Molecular analyses of Expansins from bacteria have identified residues essential for wall loosening activity and clarified the bifunctional nature of expansin binding to complex cell walls. Transgenic modulation of expansin expression modifies growth and stress physiology of plants, but not always in predictable or even understandable ways.
Simon J Mcqueenmason - One of the best experts on this subject based on the ideXlab platform.
-
Expansins abundant in secondary xylem belong to subgroup a of the α expansin gene family
Plant Physiology, 2004Co-Authors: Madoka Graymitsumune, Simon J Mcqueenmason, Ewa J Mellerowicz, Hisashi Abe, Jarmo Schrader, Anders Winzell, Fredrik Sterky, Kristina Blomqvist, Tuula T Teeri, Bjorn SundbergAbstract:Differentiation of xylem cells in dicotyledonous plants involves expansion of the radial primary cell walls and intrusive tip growth of cambial derivative cells prior to the deposition of a thick secondary wall essential for xylem function. Expansins are cell wall-residing proteins that have an ability to plasticize the cellulose-hemicellulose network of primary walls. We found expansin activity in proteins extracted from the cambial region of mature stems in a model tree species hybrid aspen (Populus tremula x Populus tremuloides Michx). We identified three alpha-expansin genes (PttEXP1, PttEXP2, and PttEXP8) and one beta-expansin gene (PttEXPB1) in a cambial region expressed sequence tag library, among which PttEXP1 was most abundantly represented. Northern-blot analyses in aspen vegetative organs and tissues showed that PttEXP1 was specifically expressed in mature stems exhibiting secondary growth, where it was present in the cambium and in the radial expansion zone. By contrast, PttEXP2 was mostly expressed in developing leaves. In situ reverse transcription-PCR provided evidence for accumulation of mRNA of PttEXP1 along with ribosomal rRNA at the tips of intrusively growing xylem fibers, suggesting that PttEXP1 protein has a role in intrusive tip growth. An examination of tension wood and leaf cDNA libraries identified another expansin, PttEXP5, very similar to PttEXP1, as the major expansin in developing tension wood, while PttEXP3 was the major expansin expressed in developing leaves. Comparative analysis of Expansins expressed in woody stems in aspen, Arabidopsis, and pine showed that the most abundantly expressed Expansins share sequence similarities, belonging to the subfamily A of alpha-Expansins and having two conserved motifs at the beginning and end of the mature protein, RIPVG and KNFRV, respectively. This conservation suggests that these genes may share a specialized, not yet identified function.
-
Expansins abundant in secondary xylem belong to subgroup a of the α expansin gene family
Plant Physiology, 2004Co-Authors: Madoka Graymitsumune, Simon J Mcqueenmason, Ewa J Mellerowicz, Hisashi Abe, Jarmo Schrader, Anders Winzell, Fredrik Sterky, Kristina Blomqvist, Tuula T Teeri, Bjorn SundbergAbstract:Differentiation of xylem cells in dicotyledonous plants involves expansion of the radial primary cell walls and intrusive tip growth of cambial derivative cells prior to the deposition of a thick secondary wall essential for xylem function. Expansins are cell wall-residing proteins that have an ability to plasticize the cellulose-hemicellulose network of primary walls. We found expansin activity in proteins extracted from the cambial region of mature stems in a model tree species hybrid aspen (Populus tremula × Populus tremuloides Michx). We identified three α-expansin genes (PttEXP1, PttEXP2, and PttEXP8) and one β-expansin gene (PttEXPB1) in a cambial region expressed sequence tag library, among which PttEXP1 was most abundantly represented. Northern-blot analyses in aspen vegetative organs and tissues showed that PttEXP1 was specifically expressed in mature stems exhibiting secondary growth, where it was present in the cambium and in the radial expansion zone. By contrast, PttEXP2 was mostly expressed in developing leaves. In situ reverse transcription-PCR provided evidence for accumulation of mRNA of PttEXP1 along with ribosomal rRNA at the tips of intrusively growing xylem fibers, suggesting that PttEXP1 protein has a role in intrusive tip growth. An examination of tension wood and leaf cDNA libraries identified another expansin, PttEXP5, very similar to PttEXP1, as the major expansin in developing tension wood, while PttEXP3 was the major expansin expressed in developing leaves. Comparative analysis of Expansins expressed in woody stems in aspen, Arabidopsis, and pine showed that the most abundantly expressed Expansins share sequence similarities, belonging to the subfamily A of α-Expansins and having two conserved motifs at the beginning and end of the mature protein, RIPVG and KNFRV, respectively. This conservation suggests that these genes may share a specialized, not yet identified function.
-
plant Expansins are a complex multigene family with an ancient evolutionary origin
Plant Physiology, 2002Co-Authors: Catherine P Darley, Andrew J Fleming, Veronica Ongaro, Ori Schipper, Sandra L Baldauf, Simon J McqueenmasonAbstract:Expansins are a group of extracellular proteins that directly modify the mechanical properties of plant cell walls, leading to turgor-driven cell extension. Within the completely sequenced Arabidopsis genome, we identified 38 expansin sequences that fall into three discrete subfamilies. Based on phylogenetic analysis and shared intron patterns, we propose a new, systematic nomenclature of Arabidopsis Expansins. Further phylogenetic analysis, including expansin sequences found here in monocots, pine (Pinus radiata, Pinus taeda), fern (Regnellidium diphyllum, Marsilea quadrifolia), and moss (Physcomitrella patens) indicate that the three plant expansin subfamilies arose and began diversifying very early in, if not before, colonization of land by plants. Closely related "expansin-like" sequences were also identified in the social amoeba, Dictyostelium discoidium, suggesting that these wall-modifying proteins have a very deep evolutionary origin.
-
local expression of expansin induces the entire process of leaf development and modifies leaf shape
Proceedings of the National Academy of Sciences of the United States of America, 2001Co-Authors: Stephane Pien, Simon J Mcqueenmason, Joanna Wyrzykowska, Cheryl C Smart, Andrew J FlemingAbstract:Expansins are a family of extracellular proteins proposed to play a key role in wall stress relaxation and, thus, in cell and tissue growth. To test the possible function of Expansins in morphogenesis, we have developed a technique that allows transient local microinduction of gene expression in transgenic plants. We have used this system to manipulate expansin gene expression in various tissues. Our results indicate that local expansin expression within the meristem induces a developmental program that recapitulates the entire process of leaf formation. Moreover, local transient induction of expansin expression on the flank of developing primordia leads to the induction of ectopic lamina tissue and thus modulation of leaf shape. These data describe an approach for the local manipulation of gene expression and indicate a role for expansin in the control of both leaf initiation and shape. These results are consistent with the action of cell division-independent mechanisms in plant morphogenesis.
-
differential expression of α and β expansin genes in the elongating leaf of festuca pratensis
Plant Molecular Biology, 2001Co-Authors: Beat Reidy, Simon J Mcqueenmason, J Nosberger, Andrew J FlemingAbstract:Grasses contain a number of genes encoding both α- and β-Expansins. These cell wall proteins are predicted to play a role in cell wall modifications, particularly during tissue elongation. We report here on the characterisation of five α- and three vegetative β-Expansins expressed in the leaf elongation zone (LEZ) of the forage grass, Festuca pratensis Huds. The expression of the predominant α-expansin (FpExp2) was localised to the vascular tissue, as was the β-expansin FpExpB3. Expression of another β-expansin (FpExpB2) was not localised to vascular tissue but was highly expressed in roots and initiating tillers. This is the first description of vegetative β-expansin gene expression at the organ and tissue level and also the first evidence of differential expression between members of this gene family. In addition, an analysis of both α- and β-expansin expression along the LEZ revealed no correlation with growth rate distribution, whereas we were able to identify a novel xyloglucan endotransglycosylase (FpXET1) whose expression profile closely mimicked leaf growth rate. These data suggest that α- and β-expansin activities in the grass leaf are associated with tissue differentiation, that Expansins involved in leaf growth may represent more minor components of the spectrum of expansin genes expressed in this tissue, and that XETs may be useful markers for the analysis of grass leaf growth.
Bjorn Sundberg - One of the best experts on this subject based on the ideXlab platform.
-
Expansins abundant in secondary xylem belong to subgroup a of the α expansin gene family
Plant Physiology, 2004Co-Authors: Madoka Graymitsumune, Simon J Mcqueenmason, Ewa J Mellerowicz, Hisashi Abe, Jarmo Schrader, Anders Winzell, Fredrik Sterky, Kristina Blomqvist, Tuula T Teeri, Bjorn SundbergAbstract:Differentiation of xylem cells in dicotyledonous plants involves expansion of the radial primary cell walls and intrusive tip growth of cambial derivative cells prior to the deposition of a thick secondary wall essential for xylem function. Expansins are cell wall-residing proteins that have an ability to plasticize the cellulose-hemicellulose network of primary walls. We found expansin activity in proteins extracted from the cambial region of mature stems in a model tree species hybrid aspen (Populus tremula x Populus tremuloides Michx). We identified three alpha-expansin genes (PttEXP1, PttEXP2, and PttEXP8) and one beta-expansin gene (PttEXPB1) in a cambial region expressed sequence tag library, among which PttEXP1 was most abundantly represented. Northern-blot analyses in aspen vegetative organs and tissues showed that PttEXP1 was specifically expressed in mature stems exhibiting secondary growth, where it was present in the cambium and in the radial expansion zone. By contrast, PttEXP2 was mostly expressed in developing leaves. In situ reverse transcription-PCR provided evidence for accumulation of mRNA of PttEXP1 along with ribosomal rRNA at the tips of intrusively growing xylem fibers, suggesting that PttEXP1 protein has a role in intrusive tip growth. An examination of tension wood and leaf cDNA libraries identified another expansin, PttEXP5, very similar to PttEXP1, as the major expansin in developing tension wood, while PttEXP3 was the major expansin expressed in developing leaves. Comparative analysis of Expansins expressed in woody stems in aspen, Arabidopsis, and pine showed that the most abundantly expressed Expansins share sequence similarities, belonging to the subfamily A of alpha-Expansins and having two conserved motifs at the beginning and end of the mature protein, RIPVG and KNFRV, respectively. This conservation suggests that these genes may share a specialized, not yet identified function.
-
Expansins abundant in secondary xylem belong to subgroup a of the α expansin gene family
Plant Physiology, 2004Co-Authors: Madoka Graymitsumune, Simon J Mcqueenmason, Ewa J Mellerowicz, Hisashi Abe, Jarmo Schrader, Anders Winzell, Fredrik Sterky, Kristina Blomqvist, Tuula T Teeri, Bjorn SundbergAbstract:Differentiation of xylem cells in dicotyledonous plants involves expansion of the radial primary cell walls and intrusive tip growth of cambial derivative cells prior to the deposition of a thick secondary wall essential for xylem function. Expansins are cell wall-residing proteins that have an ability to plasticize the cellulose-hemicellulose network of primary walls. We found expansin activity in proteins extracted from the cambial region of mature stems in a model tree species hybrid aspen (Populus tremula × Populus tremuloides Michx). We identified three α-expansin genes (PttEXP1, PttEXP2, and PttEXP8) and one β-expansin gene (PttEXPB1) in a cambial region expressed sequence tag library, among which PttEXP1 was most abundantly represented. Northern-blot analyses in aspen vegetative organs and tissues showed that PttEXP1 was specifically expressed in mature stems exhibiting secondary growth, where it was present in the cambium and in the radial expansion zone. By contrast, PttEXP2 was mostly expressed in developing leaves. In situ reverse transcription-PCR provided evidence for accumulation of mRNA of PttEXP1 along with ribosomal rRNA at the tips of intrusively growing xylem fibers, suggesting that PttEXP1 protein has a role in intrusive tip growth. An examination of tension wood and leaf cDNA libraries identified another expansin, PttEXP5, very similar to PttEXP1, as the major expansin in developing tension wood, while PttEXP3 was the major expansin expressed in developing leaves. Comparative analysis of Expansins expressed in woody stems in aspen, Arabidopsis, and pine showed that the most abundantly expressed Expansins share sequence similarities, belonging to the subfamily A of α-Expansins and having two conserved motifs at the beginning and end of the mature protein, RIPVG and KNFRV, respectively. This conservation suggests that these genes may share a specialized, not yet identified function.
Ana Cristina Miranda Brasileiro - One of the best experts on this subject based on the ideXlab platform.
-
Genome-wide analysis of expansin superfamily in wild Arachis discloses a stress-responsive expansin-like B gene.
Plant Molecular Biology, 2017Co-Authors: Larissa Arrais Guimaraes, Ana Claudia Guerra Araujo, Lucio Flavio De Alencar Figueiredo, Bruna Medeiros Pereira, Mario Alfredo De Passos Saraiva, Raquel Bispo Silva, Etienne Danchin, Patricia Messenberg Guimaraes, Ana Paula Zotta Mota, Ana Cristina Miranda BrasileiroAbstract:Expansins are plant cell wall-loosening proteins involved in adaptive responses to environmental stimuli and various developmental processes. The first genome-wide analysis of the expansin superfamily in the Arachis genus identified 40 members in A. duranensis and 44 in A. ipaensis, the wild progenitors of cultivated peanut (A. hypogaea). These Expansins were further characterized regarding their subfamily classification, distribution along the genomes, duplication events, molecular structure, and phylogeny. A RNA-seq expression analysis in different Arachis species showed that the majority of these Expansins are modulated in response to diverse stresses such as water deficit, root-knot nematode (RKN) infection, and UV exposure, with an expansin-like B gene (AraEXLB8) displaying a highly distinct stress-responsive expression profile. Further analysis of the AraEXLB8 coding sequences showed high conservation across the Arachis genotypes, with eight haplotypes identified. The modulation of AraEXLB8 expression in response to the aforementioned stresses was confirmed by qRT-PCR analysis in distinct Arachis genotypes, whilst in situ hybridization revealed transcripts in different root tissues according to the stress imposed. The overexpression of AraEXLB8 in soybean (Glycine max) composite plants remarkably decreased the number of galls in transformed hairy roots inoculated with RKN. This study improves the current understanding of the molecular evolution, divergence, and gene expression of Expansins in Arachis, and provides molecular and functional insights into the role of expansin-like B, the less-studied plant expansin subfamily.
-
Genome-wide analysis of expansin superfamily in wild Arachis discloses a stress-responsive expansin-like B gene.
Plant Molecular Biology, 2017Co-Authors: Larissa Arrais Guimaraes, Ana Paula Zotta Mota, Ana Claudia Guerra Araujo, Lucio Flavio De Alencar Figueiredo, Bruna Medeiros Pereira, Mario Alfredo De Passos Saraiva, Raquel Bispo Silva, Etienne Danchin, Patricia Messenberg Guimaraes, Ana Cristina Miranda BrasileiroAbstract:Expansins are plant cell wall-loosening proteins involved in adaptive responses to environmental stimuli and various developmental processes. The first genome-wide analysis of the expansin superfamily in the Arachis genus identified 40 members in A. duranensis and 44 in A. ipaënsis, the wild progenitors of cultivated peanut (A. hypogaea). These Expansins were further characterized regarding their subfamily classification, distribution along the genomes, duplication events, molecular structure, and phylogeny. A RNA-seq expression analysis in different Arachis species showed that the majority of these Expansins are modulated in response to diverse stresses such as water deficit, root-knot nematode (RKN) infection, and UV exposure, with an expansin-like B gene (AraEXLB8) displaying a highly distinct stress-responsive expression profile. Further analysis of the AraEXLB8 coding sequences showed high conservation across the Arachis genotypes, with eight haplotypes identified. The modulation of AraEXLB8 expression in response to the aforementioned stresses was confirmed by qRT-PCR analysis in distinct Arachis genotypes, whilst in situ hybridization revealed transcripts in different root tissues according to the stress imposed. The overexpression of AraEXLB8 in soybean (Glycine max) composite plants remarkably decreased the number of galls in transformed hairy roots inoculated with RKN. This study improves the current understanding of the molecular evolution, divergence, and gene expression of Expansins in Arachis, and provides molecular and functional insights into the role of expansin-like B, the less-studied plant expansin subfamily.
Wei Wang - One of the best experts on this subject based on the ideXlab platform.
-
The involvement of Expansins in response to water stress during leaf development in wheat.
Journal of plant physiology, 2015Co-Authors: Shan Zhou, Yangyang Han, Yanhui Chen, Xiangzhu Kong, Wei WangAbstract:Expansins are cell wall proteins that are generally considered to be the key regulator of cell wall extension during plant growth. In this study, we used two different wheat (Triticum aestivum L.) cultivars to demonstrate that Expansins are involved in wheat leaf growth and response to water stress, by regulating the expansin activity and cell wall susceptibility to Expansins. Expansin activity was associated with the relative elongation rate of leaves during leaf development, suggesting their involvement in leaf elongation. Moreover, cell wall extension characteristics and expansin gene transcription were closely involved in the leaf cell elongation region. Water stress restrains leaf growth, but the growth rate of leaves was changed after rehydration, which is consistent with the response of expansin activity to water stress. Meanwhile, increased cell wall susceptibility to expansin by water deficit played an important role in maintaining cell wall extension. Furthermore, the expansin activity in drought-resistant cultivar HF9703 was always higher than that in drought-sensitive cultivar 921842 under water stress condition, which may be correlated with the higher expansin gene expression in HF9703 versus 921842. These data provide evidence for a role of Expansins in the growth and response of wheat leaves to water stress.
-
Expansins and coleoptile elongation in wheat.
Protoplasma, 2008Co-Authors: Qiang Gao, Meirong Zhao, Qifang Guo, Shichao Xing, Wei WangAbstract:Expansins are now generally accepted to be the key regulators of wall extension during plant growth. The aim of this study was to characterize Expansins in wheat coleoptiles and determine their roles in regulating cell growth. Endogenous and reconstituted wall extension activities of wheat coleoptiles were measured. The identification of beta-Expansins was confirmed on the basis of expansin activity, immunoblot analysis, and beta-expansin inhibition. Expansin activities of wheat coleoptiles were shown to be sensitive to pH and a number of exogenously applied factors, and their optimum pH range was found to be 4.0 to 4.5, close to that of alpha-Expansins. They were induced by dithiothreitol, K(+), and Mg(2+), but inhibited by Zn(2+), Cu(2+), Al(3+), and Ca(2+), similar to those found in cucumber hypocotyls. An expansin antibody raised against TaEXPB23, a vegetative expansin of the beta-expansin family, greatly inhibited acid-induced extension of native wheat coleoptiles and only one protein band was recognized in Western blot experiments, suggesting that beta-Expansins are the main members affecting cell wall extension of wheat coleoptiles. The growth of wheat coleoptiles was closely related to the activity and expression of Expansins. In conclusion, our results suggest the presence of Expansins in wheat coleoptiles, and it is possible that most of them are members of the beta-expansin family, but are not group 1 grass pollen allergens. The growth of wheat coleoptiles is intimately correlated with expansin expression, in particularly that of beta-Expansins.
-
Expansins and coleoptile elongation in wheat.
Protoplasma, 2008Co-Authors: Qiang Gao, Meirong Zhao, Qifang Guo, Shichao Xing, Wei WangAbstract:Expansins are now generally accepted to be the key regulators of wall extension during plant growth. The aim of this study was to characterize Expansins in wheat coleoptiles and determine their roles in regulating cell growth. Endogenous and reconstituted wall extension activities of wheat coleoptiles were measured. The identification of β-Expansins was confirmed on the basis of expansin activity, immunoblot analysis, and β-expansin inhibition. Expansin activities of wheat coleoptiles were shown to be sensitive to pH and a number of exogenously applied factors, and their optimum pH range was found to be 4.0 to 4.5, close to that of α-Expansins. They were induced by dithiothreitol, K+, and Mg2+, but inhibited by Zn2+, Cu2+, Al3+, and Ca2+, similar to those found in cucumber hypocotyls. An expansin antibody raised against TaEXPB23, a vegetative expansin of the β-expansin family, greatly inhibited acid-induced extension of native wheat coleoptiles and only one protein band was recognized in Western blot experiments, suggesting that β-Expansins are the main members affecting cell wall extension of wheat coleoptiles. The growth of wheat coleoptiles was closely related to the activity and expression of Expansins. In conclusion, our results suggest the presence of Expansins in wheat coleoptiles, and it is possible that most of them are members of the β-expansin family, but are not group 1 grass pollen allergens. The growth of wheat coleoptiles is intimately correlated with expansin expression, in particularly that of β-Expansins.
-
The characteristics of Expansins in wheat coleoptiles and their responses to water stress.
Zhi wu sheng li yu fen zi sheng wu xue xue bao = Journal of plant physiology and molecular biology, 2007Co-Authors: Qiang Gao, Meirong Zhao, Qifang Guo, Shichao Xing, Wei WangAbstract:As the key regulators of cell wall extension during plant growth, Expansins play an important role in regulating the development and response of plants to adverse environment. The characteristics of Expansins in wheat coleoptiles and their responses to water stress were studied. Expansin proteins were extracted from wheat coleoptiles by the methods of Hepes or SDS. The activities of Expansins were measured with an improved extensometer and the amount of Expansins was measured by immunoblot analysis with the expansin antibody. The results showed that in coleoptiles, the extension of native cell walls depended on acidic pH, and the Expansins were found to be located at cell walls by location analysis. Expansins from wheat coleoptiles could induce cell wall extension both of cucumber hypocotyls and coleoptiles, and vice versa, albeit with differences noted in extension activity. The changes in activity and abundance of Expansins in wheat coleoptiles in response to water stress suggest that Expansins may play a significant role in the tolerance of wheat plants to water stress.
