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1.
类甜蛋白(Thaumatin-like proteins,TLPs)在植物对抗胁迫过程中发挥重要作用。该家族属多基因家族,蛋白分子量较小,具有典型的thaumatin结构域,且高度保守;典型的TLP蛋白由16个半胱氨酸残基对形成8个二硫键,三维解析结构具有功能域Ⅰ、Ⅱ和Ⅲ 3个保守功能域,表面具有“V”形酸性裂缝,保证了蛋白的催化功能;多数物种TLP蛋白归为10个聚类组,各组发生了不均衡扩增;TLP蛋白具有抗真菌、葡聚糖酶、过敏原等活性,能被激素、逆境胁迫等多种信号诱导表达,能被生物或非生物因子诱导表达,广泛参与了植物生长发育、抵御胁迫等多项生命进程,在植物先天免疫中发挥作用。通过基因工程手段,越来越多具有抗真菌潜力的TLP家族基因被用于提高植物抗病性。从类甜蛋白结构、进化、生物学功能及其应用等方面对近期研究成果进行了综述,以期为后续研究提供参考。  相似文献   

2.
β-1,3-葡聚糖酶在植物抗真菌病基因工程中的研究进展   总被引:3,自引:0,他引:3  
β-1,3-葡聚糖酶是植物抗真菌病的重要抗性物质之一,植物β-1,3-葡聚糖酶可由病原物(如Mg)、化学因子(如水杨酸、乙烯、赤霉素)或物理因子(如紫外线照射、机械损伤)等多种生物因子和非生物因子诱导产生.将外源β-1,3-葡聚糖酶基因导入植物,可提高植物的抗真菌病害的能力;而将β-1,3-葡聚糖酶基因与其他防卫蛋白基因同时导入植物,将更大程度的提高植物的抗真菌病能力,是植物抗真菌病防治的有效新途径.文章中主要对β-1,3-葡聚糖酶的生物学特性、植物β-1,3-葡聚糖酶基因在转基因植株中的独立表达及其与其他抗真菌病基因的协同表达等进行了综述.  相似文献   

3.
将天花粉蛋白、烟草几丁质酶和烟草β1,3葡聚糖酶的结构基因分别克隆到原核表达系统中进行表达,对三种基因的原核表达产物的粗提取物分别进行体外抗菌活性检测,发现三种蛋白质均有抗真菌活性。三种蛋白中任意两种蛋白的组合,其抗真菌活性显著高于单一组分的抗真菌活性。三种蛋白共同作用时,获得了更好的抗真菌效果  相似文献   

4.
王华  周鹏 《西北植物学报》2002,22(2):250-256
几丁质酶(Chitinase,Chi.)、β-1,3-葡聚糖酶(β-1,3-Glucanase,Glu.)和萝卜抗真菌蛋白(Rs-AFP2)是植物体内正常的表达产物,它们对防御植物的真菌病害具有重要的作用。基于它们在功能上具有协同作用,本研究利用基因工程技术构建了几丁质酶和抗真菌蛋白、几丁质酶和葡聚糖酶双价表达载体,通过农杆菌直接转化技术将双价表达载体转入农杆菌EHA105,最后采用PCR、DNA dot blotting技术对所获得的农杆菌工程菌株进行了鉴定分析。  相似文献   

5.
奇甜蛋白(thaumatin)是从非洲西部植物katemfe(Thaumatococcus daniellii Benth)中提取得到的几种关系相近的甜味蛋白的统称,其中最主要的为奇甜蛋白Ⅰ和奇甜蛋白Ⅱ。奇甜蛋白不仅甜度高,而且具有低热量、安全无毒以及不易诱发糖尿病等优点。因此,将奇甜蛋白基因转入园艺作物中并使之表达,用以提高可食部分的甜味,有其特别的研究意义。奇甜蛋白基因已先后在马铃薯、梨树、黄瓜、番茄等园艺作物得到表达,但仍有一些问题需要解决。现从奇甜蛋白基因的克隆、测序与表达,转基因果实的安全性检测,甜度的感官评价,甜味遗传特点以及奇甜蛋白抗真菌病害检验等几个方面综述了国内外研究进展,并对今后的研究提出了建议。  相似文献   

6.
植物β-1,3-葡聚糖酶及其基因   总被引:9,自引:0,他引:9  
β 1 ,3 葡聚糖酶属PR 2类蛋白 ,能催化真菌细胞壁的重要成分—β 1 ,3 葡聚糖和 β 1 ,3 1 ,6 葡聚糖的水解 ,水解的寡糖产物是植物防御反应的重要激发子。β 1 ,3 葡聚糖酶在植物抵抗真菌病害中发挥着不可忽视的作用 ,关于 β 1 ,3 葡聚糖酶特别是其作用机制和基因表达调控的研究取得了突出进展。β 1 ,3 葡聚糖酶基因和其它抗病相关基因的综合利用将成为植物抗真菌基因工程的有效途径。  相似文献   

7.
张敏 《植物学通报》2008,25(5):624-630
植物营养贮存蛋白(vegetative storage proteins)是广泛存在于植物营养组织且含量丰富的蛋白,最初是作为植物氮源的临时贮存形式而被人们认识。然而,不同植物中的营养贮存蛋白的生化来源和生物学特性并不相同,并且除了营养贮存功能外,更重要的是这类蛋白在植物防御中也承担着多种多样的重要角色,或具有抗虫活性,或能够抑制病原细菌和病原真菌的生长,或参与植物防御过程中的信号转导等。对植物营养贮存蛋白在植物防御中作用机制的深入研究将使这类蛋白在新型生物农药的开发和植物抗病基因工程中具有广阔的应用前景。  相似文献   

8.
各类植物由于缺少自身免疫系统的支持,因而必须依赖于其它机制来抵御外来微生物的入侵.其中的一种重要机制就是通过合成体内各类能抑制微生物生长的蛋白质来完成的[1].已报道从植物中分离出多种不同的抗真菌蛋白.广为研究的是几丁质酶和β-1,3-葡聚糖酶,认为它们在植物对真菌病的抗性中起重要作用[2,3];核糖体失活蛋白(RIPs)和一类富含半胱氨酸的碱性多肽Thionins也显示有非专一的抗真菌活性[4,5].但仍有一些蛋白质,体外表现强烈的抗真菌活性,却不属于以上范围[6,7].本文报道了豆薯种籽中一…  相似文献   

9.
PR10(病程相关蛋白10)类蛋白与植物的抵御外来病害及系统获得性抗性(SAR)有着紧密联系,而且许多PR10类蛋白都具有RNase活性,并通过这种活性抵抗外源病害。根据获得的XIOsPR10基因,将其构建到pET28a中,通过原核表达及磁珠纯化获得目的蛋白,通过RNA消化实验证实XIOsPR10重组蛋白具有RNase活性,进一步揭示了XIOsPR10蛋白的功能。  相似文献   

10.
GASA蛋白是植物特有的一类富含半胱氨酸的小分子蛋白,大多定位于细胞壁,在植物生长发育和激素信号转导过程中发挥重要作用。该蛋白具有富含12个半胱氨酸残基的GASA结构域,该结构域被认为是GASA蛋白维持空间结构和发挥功能的关键区域。该文重点综述了植物GASA蛋白的分子结构、亚细胞定位和生物学功能,并对相关领域的研究进行了展望。  相似文献   

11.
Jia Ping Zhao  Xiao Hua Su 《Planta》2010,232(4):949-962
Some pathogenesis-related proteins (PR proteins) are subject to positive selection, while others are under negative selection. Here, we report the patterns of molecular evolution in thaumatin-like protein (TLP, PR5 protein) genes of Populus trichocarpa. Signs of positive selection were found in 20 out of 55 Populus TLPs using the likelihood ratio test and ML-based Bayesian methods. Due to the connection between the acidic cleft and the antifungal activity, the secondary structure and three-dimensional structure analyses predicted antifungal activity β-1,3-glucanase activities in these TLPs. Moreover, the coincidence with variable basic sites in the acidic cleft and positively selected sites suggested that fungal diseases may have been the main environmental stress that drove rapid adaptive evolution in Populus.  相似文献   

12.
13.
Thaumatin-like proteins (TLPs) were isolated and characterized from fruits and leaves of elderberry (Sambucus nigra) and their corresponding genes cloned. In addition, the developmental regulation and induction of the different TLPs was followed in some detail. Ripening berries accumulated a fruit-specific TLP during the final stages of maturation. This fruit-specific TLP had no antifungal activity and was devoid of beta-glucanase activity. Leaves constitutively expressed a TLP that closely resembled the fruit-specific homologue. Treatment with jasmonate methyl ester induced two additional TLPs in leaves but did not induce or enhance the expression of TLPs in immature berries. In contrast to jasmonate methyl ester, both ethephon and garlic extract induced the expression of a TLP in unripe berries that normally do not express any TLP. Sequence analysis and molecular modeling indicated that all elderberry thaumatin-like proteins share a high sequence similarity with group-5 pathogenesis-related proteins. However, the proteins encoded by the different sequences differed from each other in isoelectric point and the distribution of the charges on the surface of the molecule.  相似文献   

14.
15.
Osmotin, a pathogenesis-related antifungal protein, is relevant in induced plant immunity and belongs to the thaumatin-like group of proteins (TLPs). This article describes comparative structural and functional analysis of the two osmotin isoforms cloned from Phytophthora-resistant wild Piper colubrinum. The two isoforms differ mainly by an internal deletion of 50 amino acid residues which separates them into two size categories (16.4 kDa-PcOSM1 and 21.5 kDa-PcOSM2) with pI values 5.6 and 8.3, respectively. Recombinant proteins were expressed in E. coli and antifungal activity assays of the purified proteins demonstrated significant inhibitory activity of the larger osmotin isoform (PcOSM2) on Phytophthora capsici and Fusarium oxysporum, and a markedly reduced antifungal potential of the smaller isoform (PcOSM1). Homology modelling of the proteins indicated structural alterations in their three-dimensional architecture. Tertiary structure of PcOSM2 conformed to the known structure of osmotin, with domain I comprising of 12 β-sheets, an α-helical domain II and a domain III composed of 2 β-sheets. PcOSM1 (smaller isoform) exhibited a distorted, indistinguishable domain III and loss of 4 β-sheets in domain I. Interestingly, an interdomain acidic cleft between domains I and II, containing an optimally placed endoglucanase catalytic pair composed of Glu-Asp residues, which is characteristic of antifungal PR5 proteins, was present in both isoforms. It is well accepted that the presence of an acidic cleft correlates with antifungal activity due to the presence of endoglucanase catalytic property, and hence the present observation of significantly reduced antifungal capacity of PcOSM1 despite the presence of a strong acidic cleft, is suggestive of the possible roles played by other structural features like domain I or/and III, in deciding the antifungal potential of osmotin.  相似文献   

16.
Plant stress proteins of the thaumatin-like family discovered in animals   总被引:4,自引:0,他引:4  
Thaumatin-like proteins (TLPs) are polypeptides of about 200 residues synthesized by plants in response to fungal infection. In addition to the exceptionally strong sweet taste exhibited by some members, they are also reported to be endowed with endo-beta-1,3-glucanase activity and alpha-amylase inhibiting properties. However, the detailed mechanism of their antifungal action is not completely understood. So far, TLPs have only been described in plants, with several members of the family expressed in the same species. Here, for the first time in animals, we report the identification of two genes encoding members of the thaumatin-like proteins family in the desert locust Schistocerca gregaria and show their expression in different parts of the body. Southern blot and Western blot experiments revealed the presence of orthologous genes and their expression products in the related species Locusta migratoria. A search through the available genomes yielded similar sequences in the nematode Caenorhabditis but not in Drosophila and other insects. A three-dimensional model of S. gregaria TLP suggests a glucanase function. As in plants, TLPs could play a defense role in insects against pathogens.  相似文献   

17.
Crystal structure analysis of NP24-I: a thaumatin-like protein   总被引:1,自引:0,他引:1  
Ghosh R  Chakrabarti C 《Planta》2008,228(5):883-890
The crystal structure of NP24-I, an isoform of the thaumatin-like protein (TLP) NP24 from tomato, has been reported. A prominent acidic cleft is observed between domains I and II of the three-domain structure of this antifungal protein, a feature common to other antifungal TLPs. The defensive role of the TLPs has also been attributed to their beta-1,3-glucanase activity and here too the acidic cleft is reported to play a vital role. NP24 is known to bind beta-glucans and so a linear beta-1,3-glucan molecule has been docked in the interdomain cleft of NP24-I. From the docked complex it is observed that the beta-glucan chain is so positioned in the cleft that a Glu and Asp residue on either side of it may form a catalytic pair to cause the cleavage of a glycosidic bond. NP24 has been reported to be an allergenic protein and an allergenic motif could be identified on the surface of the helical domain II of NP24-I. In addition, some allergenic motifs bearing high similarity/identity with some predicted Ig-E binding motifs of closely related allergenic TLPs like Jun a 3 (Juniperus ashei, from mountain cedar pollen) and banana-TLP have been identified on the molecular surface of NP24-I.  相似文献   

18.
 The pulp of ripe bananas (Musa acuminata) contains an abundant thaumatin-like protein (TLP). Characterization of the protein and molecular cloning of the corresponding gene from banana demonstrated that the native protein consists of a single polypeptide chain of 200 amino acid residues. Molecular modelling further revealed that the banana thaumatin-like protein (Ban-TLP) adopts an overall fold similar to that of thaumatin and thaumatin-like PR-5 proteins. Although the banana protein exhibits an electrostatically polarized surface, which is believed to be essential for the antifungal properties of TLPs, it is apparently devoid of antifungal activity towards pathogenic fungi. It exhibits a low but detectable in vitro endo-β-1,3-glucanase (EC 3.2.1.x) activity. As well as being present in fruits, Ban-TLP also occurs in root tips where its accumulation is enhanced by methyl jasmonate treatment of plants. Pulp of plantains (Musa acuminata) also contains a very similar TLP, which is even more abundant than its banana homologue. Our results demonstrate for the first time that fruit-specific (abundant) TLPs are not confined to dicots but occur also in fruits of monocot species. The possible role of the apparent widespread accumulation of fruit-specific TLPs is discussed. Received: 7 January 2000 / Accepted: 26 April 2000  相似文献   

19.
A transgenic wheat line constitutively expressing genes encoding a class IV acidic chitinase and an acidic beta-1,3-glucanase, showed significant delay in spread of Fusarium head blight (scab) disease under greenhouse conditions. In an earlier work, we observed a lesion-mimic phenotype in this transgenic line when homozygous for transgene loci. Apoplastic fluid (AF) extracted from the lesion-mimic plants had pathogenesis-related (PR) proteins belonging to families of beta-1,3-glucanases, chitinases, and thaumatin-like proteins (TLPs). AF had growth inhibitory activity against certain fungal pathogens, including Fusarium graminearum and Gaeumannomyces graminis var. tritici. Through a two-step ion-exchange chromatography protocol, we recovered many PR proteins and a few uncharacterized proteins. Three individual protein bands corresponding to a TLP (molecular mass, 16 kDa) and two beta-1,3-glucanases (molecular mass, 32 kDa each) were purified and identified by tandem mass spectrometry. We measured the in vitro antifungal activity of the three purified enzymes and a barley class II chitinase (purified earlier in our laboratory) in microtiter plate assays with macroconidia or conidiophores of F. graminearum and Pyrenophora tritici-repentis. Mixtures of proteins revealed synergistic or additive inhibitory activity against F. graminearum and P. tritici-repentis hyphae. The concentrations of PR proteins at which these effects were observed are likely to be those reached in AF of cells exhibiting a hypersensitive response. Our results suggest that apoplastic PR proteins are antifungal and their antimicrobial potency is dependent on concentrations and combinations that are effectively reached in plants following microbial attack.  相似文献   

20.
Thaumatin‐like proteins (TLPs) share structural similarity with the sweet‐tasting thaumatin protein but exhibit antifungal activity by inhibiting growth of fungal pathogens. In a Tenebrio model, two TLP genes were identified by RNA‐sequencing analysis and genome sequencing. Both TmTLP1 and TmTLP2 genes contain 729 nucleotide sequences encoding 242 amino acid residues, including an initiation codon (ATG) and a termination codon (TAA). Interestingly, TmTLPs are proteins with 14 central cysteine residues that may have an important role in structure formation. These data will be used to characterize the innate immune functions of TmTLPs in Tenebrio molitor.  相似文献   

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