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膨胀素是一类具有非水解活性的细胞壁松弛蛋白,参与植物生长发育过程中细胞壁的修饰。大多数植物中都发现有膨胀素基因家族成员存在,其功能涉及植物生长发育的各个方面,包括营养生长、形态发生、受精授粉、果实成熟等,并表现出高度的组织、器官和细胞特异性。本文综述膨胀素在种子萌发、叶的发育、根茎生长、花的发育等生长发育过程中的作用。 相似文献
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膨胀素——一个引人注目的细胞壁松弛酶候选者 总被引:3,自引:0,他引:3
植物的生长是植物生理学中一个最基本且重要的问题。细胞膨胀生长(扩大和伸长)的前提是使细胞壁松弛和不可逆伸展。生物物理和生物化学分析表明,细胞壁衬质是控制细胞壁生长的最重要的因素[4]。目前,人们普遍认为,衬质多糖作为“链”(tether),把纤维素微纤丝结合在一起[9];或作为“填补物”(filler),防止微纤丝聚集[15,22,30]。并进一步认为,细胞壁松弛的机理是衬质多糖被水解断裂[1,9,13,14]。据报道,多种修饰酶(如葡聚糖酶[1,9,19]、葡萄糖苷酶[19,27]、半乳糖苷酶[17,31]、果胶甲酯酶[11]、IAA氧化酶[2]、过氧… 相似文献
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细胞外基质在植物发育中的作用 总被引:2,自引:0,他引:2
植物细胞壁是由纤维素和果胶交联的多糖和蛋白质构成的既彼此独立,又相互作用的三维动力学网络。和动物的细胞外基质一样,植物细胞壁中的许多成分积极地参与植物细胞发育过程的调节,它们以某种方式将信息传递给细胞,调节细胞的行为,以便对各种外界环境作出相应的反应。因此细胞壁不再是一种环绕植物细胞的惰性结构,比起细胞壁,植物细胞外基质这一名词更能反映出这一动力学的特性。 相似文献
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细胞外基质在植物发育中的作用 总被引:6,自引:1,他引:5
植物细胞壁是由纤维素和果胶交联的多糖和蛋白质构成的既彼此独立,又相互作用的三维动力学网络。和动物的细胞外基质一样,植物细胞壁中的许多成分积极地参与植物细胞发育过程的调节,它们以某种方式将信息传递给细胞,调节细胞的行为,以便对各种外界环境作出相应的反应。因此细胞壁不再是一种环绕植物细胞的惰性结构,比起细胞壁,植物细胞外基质这一名词更能反映出这一动力学的特性。 相似文献
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The growing world of expansins 总被引:34,自引:0,他引:34
Cosgrove DJ Li LC Cho HT Hoffmann-Benning S Moore RC Blecker D 《Plant & cell physiology》2002,43(12):1436-1444
Expansins are cell wall proteins that induce pH-dependent wall extension and stress relaxation in a characteristic and unique manner. Two families of expansins are known, named alpha- and beta-expansins, and they comprise large multigene families whose members show diverse organ-, tissue- and cell-specific expression patterns. Other genes that bear distant sequence similarity to expansins are also represented in the sequence databases, but their biological and biochemical functions have not yet been uncovered. Expansin appears to weaken glucan-glucan binding, but its detailed mechanism of action is not well established. The biological roles of expansins are diverse, but can be related to the action of expansins to loosen cell walls, for example during cell enlargement, fruit softening, pollen tube and root hair growth, and abscission. Expansin-like proteins have also been identified in bacteria and fungi, where they may aid microbial invasion of the plant body. 相似文献
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The expansin superfamily of plant proteins is made up of four families, designated α-expansin, β-expansin, expansin-like A and expansin-like B. α-Expansin and β-expansin proteins are known to have cell-wall loosening activity and to be involved in cell expansion and other developmental events during which cell-wall modification occurs. Proteins in these two families bind tightly to the cell wall and their activity is typically assayed by their stimulation of cell-wall extension and stress relaxation; no bona fide enzymatic activity has been detected for these proteins. α-Expansin proteins and some, but not all, β-expansin proteins are implicated as catalysts of 'acid growth', the enlargement of plant cells stimulated by low extracellular pH. A divergent group of β-expansin genes are expressed at high levels in the pollen of grasses but not of other plant groups. They probably function to loosen maternal cell walls during growth of the pollen tube towards the ovary. All expansins consist of two domains; domain 1 is homologous to the catalytic domain of proteins in the glycoside hydrolase family 45 (GH45); expansin domain 2 is homologous to group-2 grass pollen allergens, which are of unknown biological function. Experimental evidence suggests that expansins loosen cell walls via a nonenzymatic mechanism that induces slippage of cellulose microfibrils in the plant cell wall. 相似文献
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Results from various expansin related studies have demonstrated that expansins present an opportunity to improve various crops in many different aspects ranging from yield and fruit ripening to improved stress tolerance.Abstract
The recent advances in expansin studies were reviewed. Besides producing the strength that is needed by the plants, cell walls define cell shape, cell size and cell function. Expansins are cell wall proteins which consist of four sub families; α-expansin, β-expansin, expansin-like A and expansin-like B. These proteins mediate cell wall loosening and they are present in all plants and in some microbial organisms and other organisms like snails. Decades after their initial discovery in cucumber, it is now clear that these small proteins have diverse biological roles in plants. Through their ability to enable the local sliding of wall polymers by reducing adhesion between adjacent wall polysaccharides and the part they play in cell wall remodeling after cytokinesis, it is now clear that expansins are required in almost all plant physiological development aspects from germination to fruiting. This is shown by the various reports from different studies using various molecular biology approaches such as gene achieve these many roles through their non-enzymatic wall loosening ability. This paper reviews and summarizes some of the reported functions of expansins and outlines the potential uses of expansins in crop improvement programs.14.
Abstract: Expansins are a class of proteins identified by their ability to induce the extension of isolated plant cell walls. Expansins are encoded by an extensive multigene family in higher plants, several members of which have been shown to be expressed in a tissue-specific manner. Besides playing an apparently key role in wall expansion, and hence in cell growth, expansins have been implicated in an increasing number of processes during plant growth and development. These include: leaf organogenesis, fruit softening, and wall disassembly. A second class of closely related proteins (referred to as β-expansins) has been identified. Other recent advances in expansin research include the recovery of transgenic plants with altered level of expansins, and the production of recombinant expansins in het-erologous expression systems. 相似文献
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Antero Ramos Edith Garay-Serrano Enrique César Leticia Montoya Víctor M. Bandala 《Symbiosis (Philadelphia, Pa.)》2018,74(1):1-10
Expansins are non-enzymatic cell wall proteins that mediate plant growth by catalyzing loosening of cell walls without lysing the wall polymers. Advances in the field of bioinformatics have facilitated the prediction of the members of expansin gene family across several model plants. Expansins constitutes into four sub-families; α-expansin, β-expansin, expansin-like A and expansin-like B. Biological functions of expansin gene family include diverse aspects of plant growth and development, shoot and root elongation, leaf morphogenesis, flower and fruit development, embryogenesis, pollen tube growth, stress tolerance, etc. Recent studies have demonstrated the role of expansins in plant-symbiotic interactions. The present review reveals the factors that govern plant-arbuscular mycorrhizal fungi (AMF) and legume-rhizobia symbioses; and the genes that participate in these diverse symbiont interactions. Further, we focus on the expression profiles and the functions of expansins during plant-AMF and legume-rhizobia interactions. The key roles of expansin proteins during AMF invasion, arbuscule formation, rhizobial infection and nodule organogenesis were uncovered during symbioses. This review summarizes discoveries that support the key and versatile roles of various expansin members in the plant-mycorrhizal and legume-rhizobial symbioses. 相似文献
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Beta-expansins accumulate to high levels in grass pollen, a feature apparently unique to grasses. These proteins, which are major human allergens, facilitate pollen tube penetration of the maize stigma and style (the silk). Here we report that treatment of maize silk cell walls with purified β-expansin from maize pollen led to solubilization of wall matrix polysaccharides, dominated by feruloyated highly substituted glucuronoarabinoxylan (60%) and homogalacturonan (35%). Such action was selective for cell walls of grasses, and indicated a target preferentially found in grass cell walls, probably the highly substituted glucuronoarabinoxylan. Several tests for lytic activities by β-expansin were negative and polysaccharide solubilization had weak temperature dependence, which indicated a non-enzymatic process. Concomitant with matrix solubilization, β-expansin treatment induced creep, reduced the breaking force and increased the plastic compliance of wall specimens. From comparisons of the pH dependencies of these processes, we conclude that matrix solubilization was linked closely to changes in wall plasticity and breaking force, but not so closely coupled to cell wall creep. Because matrix solubilization and increased wall plasticity have not been found with other expansins, we infer that these novel activities are linked to the specialized role of grass pollen β-expansins in promotion of penetration of the pollen tube through the stigma and style, most likely by weakening the middle lamella. 相似文献
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Comprehensive approach to genes involved in cell wall modifications in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> 总被引:2,自引:0,他引:2
The plant cell wall is of supermolecular architecture, and is composed of various types of heterogeneous polymers. A few thousand enzymes and structural proteins are directly involved in the construction processes, and in the functional aspects of the dynamic architecture in Arabidopsis thaliana. Most of these proteins are encoded by multigene families, and most members within each family share significant similarities in structural features, but often exhibit differing expression profiles and physiological functions. Thus, for the molecular dissection of cell wall dynamics, it is necessary to distinguish individual members within a family of proteins. As a first step towards characterizing the processes involved in cell wall dynamics, we have manufactured a gene-specific 70-mer oligo microarray that consists of 765 genes classified into 30 putative families of proteins that are implicated in the cell wall dynamics of Arabidopsis. By using this array system, we identified several sets of genes that exhibit organ preferential expression profiles. We also identified gene sets that are expressed differentially at certain specific growth stages of the Arabidopsis inflorescence stem. Our results indicate that there is a division of roles among family members within each of the putative cell wall-related gene families. 相似文献
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Expansins are thought to be key regulators of cell wall extension during plant growth. In this study, we isolated 18 expansin
genes from wheat, nine of which encode α-expansins while the other nine code for β-expansins. The cysteine-rich and tryptophan-rich
regions of the deduced amino acid sequences of all 18 expansins were highly conserved. Genomic sequences were obtained for
17 of the genes, and their intron patterns were determined. Four (A, C, D, E) of the six intron positions known in expansin
genes from other species were found to be occupied in these wheat expansin genes. Five wheat expansin genes were mapped to
chromosomes 1L, 2L, 5L and 6L respectively, by in silico and comparative mapping. The 18 wheat expansin genes were expressed
in leaf, root and the developing seed. Moreover, it was demonstrated that four β-expansin genes were up-regulated in the internode
tissue in F1 hybrids, suggesting that changes in the regulation of these genes in hybrid might contribute to the heterosis observed in
internode length and plant height. We therefore conclude that expansins are encoded by a multigene family in wheat, and could
play important roles in growth and development.
Z. Lin and Z. Ni contributed to this work equally 相似文献
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Silvia Dal Santo Marianna Fasoli Erika Cavallini Giovanni Battista Tornielli Mario Pezzotti Sara Zenoni 《Plant signaling & behavior》2011,6(12):2031-2034
Expansins are wall-loosening proteins that induce wall stress relaxation and irreversible wall extension in a pH-dependent manner. Despite a substantial body of work has been performed on the characterization of many expansins genes in different plant species, the knowledge about their precise biological roles during plant development remains scarce. To yield insights into the expansion process in Petunia hybrida, PhEXPA1, an expansin gene preferentially expressed in petal limb, has been characterized. The constitutive overexpression of PhEXPA1 significantly increased expansin activity, cells size and organ dimensions. Moreover, 35S::PhEXPA1 transgenic plants exhibited an altered cell wall polymer composition and a precocious timing of axillary meristem development compared with wild-type plants. These findings supported a previous hypothesis that expansins are not merely structural proteins involved in plant cell wall metabolism but they also take part in many plant development processes. Here, to support this expansins dual role, we discuss about differential cell wall-related genes expressed in PhEXPA1 expression mutants and gradients of altered petunia branching pattern. 相似文献