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1.
Tapping into molecular conversation between oomycete plant pathogens and their hosts 总被引：1，自引：1，他引：0
Mahmut Tör 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):57-69
Several plant pathogenic oomycetes have been under investigation using modern molecular approaches. Genome sequencing and
annotations are underway or near to completion for some of the species. Pathogen-associated molecular pattern molecules (PAMPs)
and effector molecules perform inter- and intracellular tasks as adaptation factors and manipulators of the defence network.
Hundreds of secreted putative effectors have been discovered and conserved molecular patterns such as RXLR and EER motifs
have been identified and used for classifications. PAMPs and effectors are recognized directly or indirectly by the pattern
recognition receptors at the cell surface including receptor-like kinases and receptor-like proteins, and/or by nucleotide
binding site–leucine rich repeat proteins within the cytoplasm. The current knowledge of effectors, immune receptors and the
defence network, will help us understand the ‘intricate genetic dance’ between the oomycete pathogens and their hosts. This
review concentrates on the recent findings in oomycete-plant interactions. 相似文献
2.
L. C. van Loon 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(3):243-254
Non-pathogenic soilborne microorganisms can promote plant growth, as well as suppress diseases. Plant growth promotion is
taken to result from improved nutrient acquisition or hormonal stimulation. Disease suppression can occur through microbial
antagonism or induction of resistance in the plant. Several rhizobacterial strains have been shown to act as plant growth-promoting
bacteria through both stimulation of growth and induced systemic resistance (ISR), but it is not clear in how far both mechanisms
are connected. Induced resistance is manifested as a reduction of the number of diseased plants or in disease severity upon
subsequent infection by a pathogen. Such reduced disease susceptibility can be local or systemic, result from developmental
or environmental factors and depend on multiple mechanisms. The spectrum of diseases to which PGPR-elicited ISR confers enhanced
resistance overlaps partly with that of pathogen-induced systemic acquired resistance (SAR). Both ISR and SAR represent a
state of enhanced basal resistance of the plant that depends on the signalling compounds jasmonic acid and salicylic acid,
respectively, and pathogens are differentially sensitive to the resistances activated by each of these signalling pathways.
Root-colonizing Pseudomonas bacteria have been shown to alter plant gene expression in roots and leaves to different extents, indicative of recognition
of one or more bacterial determinants by specific plant receptors. Conversely, plants can alter root exudation and secrete
compounds that interfere with quorum sensing (QS) regulation in the bacteria. Such two-way signalling resembles the interaction
of root-nodulating Rhizobia with legumes and between mycorrhizal fungi and roots of the majority of plant species. Although ISR-eliciting rhizobacteria
can induce typical early defence-related responses in cell suspensions, in plants they do not necessarily activate defence-related
gene expression. Instead, they appear to act through priming of effective resistance mechanisms, as reflected by earlier and
stronger defence reactions once infection occurs. 相似文献
3.
Post-translational modifications in effectors and plant proteins involved in host–pathogen conflicts
Molecular interplay between two species is largely driven by protein–protein interactions and protein modifications that set the pace of co-evolution in these species. During host–pathogen interactions, proteins involved in virulence and defence impart tempospatial dynamic post-translational modifications (PTMs) to gain advantage for the causative species. Pathogens mainly cause disease in plant hosts by secreting elicitors (peptides and small molecules) or proteins in the inter- and intracellular space of host cells. These pathogen proteins have evolved a wide array of sophisticated mechanisms to manipulate host responses, including resistance. Through a set of diverse events ranging from PTMs to post-translational oligomerization, these proteins are able to enhance virulence and suppress the otherwise elaborate plant immune system. Similarly, PTMs adapted by host proteins often lead to the activation of a robust defence response. Insights into the PTMs of pathogen and host proteins are therefore germane to the understanding of the co-evolutionary arms race. This review summarizes the characterization of PTMs in pathogen effectors and their target host proteins. Based on this, a metaphorical view of host–pathogen conflicts is proposed, where PTMs act as molecular pivots in a 3D combinatorial game model – a novel abstraction of the arms race, where these molecular pivots restore the balance of competition between the two organisms. 相似文献
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Plant pathogens colonize their host through the secretion of effector proteins that modulate plant metabolism and immune responses to their benefit. Plants evolve towards effector recognition, leading to host immunity. Typically, pathogen effectors are targets for recognition through plant receptors that are encoded by resistance genes. Resistance gene mediated crop immunity puts a tremendous pressure on pathogens to adapt and alter their effector repertoire to overcome recognition. We argue that the type of effector that is recognized by the host may have considerable implications on the durability of resistance against filamentous plant pathogens. Effector genes that are conserved among pathogens and reside in core genome regions are most likely to hold indispensable virulence functions. Consequently, the cost for the pathogen to overcome recognition by the host is higher than for diversified, host‐specific effectors with a quantitative impact on virulence. Consequently, resistance genes that directly target conserved effector proteins without the interception of other effector proteins are potentially excellent resistance resources. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
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In Arabidopsis, abscisic acid (ABA) application can induce resistance by priming for callose deposition; this resistance is impaired in ABA-deficient and -insensitive mutants. In tomato, ABA-deficiency causes resistance to Botrytis cinerea. Here, we show that callose deposition after B. cinerea inoculation is weaker in the ABA-deficient sitiens tomato mutant compared to the wild type (WT). Inhibition of callose synthesis did not affect resistance in sitiens, but caused additional susceptibility in WT. These findings indicate that callose deposition is not part of sitiens defence responses that are effective in blocking B. cinerea and suggest that callose deposition only contributes to WT basal resistance. Furthermore, also in tomato callose formation is at least in part ABA-dependent. However, it seems that in contrast to Arabidopsis, basal ABA levels in tomato are sufficiently high to prime for callose deposition. 相似文献
8.
Identification of wheat blue dwarf phytoplasma effectors targeting plant proliferation and defence responses 
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下载免费PDF全文 The identification of effectors from pathogenic microbes is one of the most important subjects for elucidating infection mechanisms. Wheat blue dwarf (WBD) phytoplasma causes dwarfism, witches' broom, and yellow leaf tips in wheat plants, resulting in severe yield loss in northwestern China. In this study, 37 candidate effector proteins were transiently expressed in Nicotiana benthamiana. Plants expressing the SAP11‐like protein SWP1 exhibited typical witches' broom. Interestingly, another protein, SWP11, induced both cell death and defence responses, including H2O2 accumulation and callose deposition. Analysis by qRT‐PCR was used to show that a marker gene of the hypersensitive response, HIN1, and three pathogenesis‐related genes, PR1, PR2 and PR3, were significantly up‐regulated in leaves of N. benthamiana expressing SWP11. In addition, SWP12 and SWP21 (TENGU‐like) were shown to suppress SWP11‐, BAX‐, and/or INF1‐induced cell death. These results indicated that SWP21 has a distinct role in virulence compared with TENGU and that WBD phytoplasma possesses effectors that target plant proliferation and defence responses. The ability of these effectors to trigger or suppress plant immunity provides new insights into the phytoplasma–plant interaction. 相似文献
9.
James E. Rookes Marion L. Wright David M. Cahill 《Physiological and Molecular Plant Pathology》2008,72(4-6):151-161
Arabidopsis thaliana (Arabidopsis) Col-0 was inoculated with Phytophthora cinnamomi to assess the interaction and defence responses involved. Pathogen ingress and asexual reproduction occurred on root tissue but not leaf tissue. The colonisation of root tissue did not cause disease symptoms or plant death, indicating that Arabidopsis Col-0 was tolerant of the infection. The induction of several plant defence responses including the expression of defence-related genes were found, with differences displayed between inoculated root and leaf tissue. Arabidopsis defence-related gene mutant/over-expressing lines were also inoculated with P. cinnamomi but none of the lines tested exhibited a marked increase in susceptibility to the pathogen. 相似文献
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Y. Abu-Nada A. C. Kushalappa W. D. Marshall K. Al-Mughrabi A. Murphy 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):375-391
Metabolite profiles based on GC/MS were used to study the temporal dynamics of metabolites in potato leaves following pathogen
inoculation. In the polar and non-polar plant extracts a total of 106 consistent peaks were detected, of which 95 metabolites
were tentatively identified. Following pathogen inoculation, the abundances of 42 metabolites were significantly increased
or decreased, and these metabolites were designated as Pathogenesis-Related (PR) Metabolites. Factor analysis of the abundance
of 106 metabolites identified four plant–pathogen interaction functions: (i) homeostasis; (ii) primary defence; (iii) secondary
defence; (iv) collapse of primary and secondary defence responses. During the primary and secondary defence phases, dramatic
changes in the amino acids, known precursors of several plant defence-related metabolites, were observed. Plausible satellite-networks
of metabolic pathways leading to the up-regulation of these families of amino acids and other secondary metabolites, and their
potential application for the evaluation of horizontal resistance in potato against the late blight pathogen is discussed. 相似文献
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Sheath blight, caused by anastomosis group 1-IA of Rhizoctonia solani Kühn (teleomorph Thanatephorus cucumeris (Frank) Donk), is one of the most destructive rice diseases worldwide. The pathogen is able to infect plants belonging to
more than 27 families, including many economically important monocots and dicots such as rice, wheat, alfalfa, bean, peanut,
soybean, cucumber, papaya, corn, potato, tomato and sugar beet. It is a soil borne necrotrophic fungus that survives in plant
debris as sclerotia, which are small brown-to-black, rocklike reproductive structures. The sclerotia can survive in the soil
for several years and infect rice plants at the water-plant interface in the flooded field by producing mycelia. Management
of rice sheath blight requires an integrated approach based on the knowledge of each stage of the disease and cytomolecular
aspects of rice defence responses against R. solani. This review summarizes current knowledge on molecular aspects of R. solani pathogenicity, genetic structure of the pathogen populations, and the rice-R. solani interaction with emphasis on cellular and molecular defence components such as signal transduction pathways, various plant
hormones, host defence genes and production of defence-related proteins involved in basal and induced resistance in rice against
sheath blight disease. 相似文献
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Monik Evelin Leite João Bosco dos Santos Pedro Martins Ribeiro Jr. Danuza Araujo de Souza Letícia Aparecida de Castro Lara Mário Lúcio Vilela de Resende 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(2):391-404
The aim of this study was to investigate changes in defence compounds of common bean cultivars with different levels of resistance to the fungus Sclerotinia sclerotiorum and determine the relation of the compounds to pathogen tolerance. The lines were inoculated with the pathogen and assessed for enzymatic and non-enzymatic parameters related to plant defence: peroxidases (POX), polyphenol oxidases (PPO), catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX), total soluble phenol and lignin contents. Stem tissue samples were collected from two regions of the plant for biochemical analyses. Stem tissue samples were collected from two regions of the plant for biochemical analyses. In the position one, 5 cm of the stem was collected from the region with necrosis caused by the pathogen, and in the position two, 5 cm of the stem was collected from the end of the position one at the times of 12, 24, 48, 72, 96 and 120 h after inoculation (HAI). Greater lignin and total soluble phenol contents and greater induction of POX and SOD activity in inoculated plants in the region near the inoculation (position one) indicate local activation with later signalling for activation of defence mechanisms in other regions of the plant. The genotype with a greater level of resistance was superior to the susceptible one in regard to lignin production and the activities of POX, APX and SOD defence enzymes. These results suggest that a combination of these defence responses in common bean may contribute to greater plant resistance to the pathogen and that these enzymes have potential use in selection of common bean genotypes. 相似文献
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During plant–virus interactions, defence responses are linked to the accumulation of reactive oxygen species (ROS). Importantly, ROS play a dual role by (1) eliciting pathogen restriction and often localized death of host plant cells at infection sites and (2) as a diffusible signal that induces antioxidant and pathogenesis-related defence responses in adjacent plant cells. The outcome of these defences largely depends on the speed of host responses including early ROS accumulation at virus infection sites. Rapid host reactions may result in early virus elimination without any oxidative stress (i.e. a symptomless, extreme resistance). A slower host response allows a certain degree of virus replication and movement resulting in oxidative stress and programmed death of affected plant cells before conferring pathogen arrest (hypersensitive response, HR). On the other hand, delayed host attempts to elicit virus resistance result in an imbalance of antioxidative metabolism and massively stressed systemic plant tissues (e.g. systemic chlorotic or necrotic symptoms). The final consequence of these processes is a partial or almost complete loss of control over virus invasion (compatible infections). 相似文献
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A mechanism of virulence mediated byhrp-genes is present in many Gram-negative bacterial pathogens. It involves delivery of effector proteins into host cellsvia the type III secretion system (TTSS) and the interaction of TTSS effectors with plant proteins. These interactions may either
promote responses beneficial to the pathogen or trigger the hypersensitive response if an effector is recognized by corresponding
resistance protein.Pantoea agglomerans, which is widespread in nature mainly as an epiphyte, has evolved into ahrp-dependent and host-specific tumorigenic pathogen by acquiring a plasmid containing a pathogenicity island (PAI). This PAI
harbors ahrp-gene cluster, and genes encoding for TTSS effector proteins and biosynthesis of IAA and cytokinins. The results reviewed
describe how the interplay between negative-acting and positive-acting TTSS effectors determines the transformation ofP. agglomerans into two related pathovars. Furthermore, the PAI’s structure supports the premise that these pathovars are recently evolved
pathogens. Finally, the possible interaction between TTSS effectors and phytohormones for gall formation is proposed. 相似文献
18.
John A Lucas 《Pest management science》1999,55(2):193-196
The idea that plants might be able to develop a form of acquired immunity to infection following exposure to a pathogen has been current ever since discovery of the animal immune system in the later years of the nineteenth century. Early attempts to demonstrate a comparable system in plants focused on the detection of precipitating antibodies and hence were doomed to failure. Nevertheless, largely anecdotal evidence for plant immunisation continued to accumulate, culminating in the discovery of phytoalexins in the 1940s. Convincing evidence for systemic changes in plant resistance following an inducer inoculation was not available until 20 years later, when pioneering work on tobacco infected with blue mould (Peronospora tabacina) or tobacco mosaic virus (TMV) showed that tissues remote from the inoculation site were altered in disease reaction type. Increased resistance was expressed as a reduction in lesion numbers and size, and a reduced rate of pathogen reproduction. Systemic acquired resistance (SAR) has now been demonstrated in at least 20 plant species in at least six plant families, although detailed genetic or molecular analysis has mainly been confined to a few models, such as tobacco, cucumber and Arabidopsis. SAR is associated with the coordinate induction of genes encoding defence proteins which can be used as molecular markers of the response. The availability of Arabidopsis mutants altered in the induction and expression of SAR is now providing new insights into the signal transduction pathway(s) involved, and will enable comparison with the molecular mechanisms operating in other plant taxa. Important unresolved questions concern the nature of the translocated signal, the mechanism of defence ‘priming’, efficacy of the response against different pathogens, and practical exploitation of SAR in crop protection. The first generation of chemical plant defence activators is now commercially available and optimal use of these SAR inducers in integrated disease control requires further evaluation. The prospects for engineering transgenic crops altered in the regulation or expression of SAR is also a subject for further investigation. © 1999 Society of Chemical Industry 相似文献
19.
《Physiological and Molecular Plant Pathology》2008,72(4-6):126-134
Plant innate immunity relies on specialised immune receptors that can detect and defend against a wide variety of microbes. The first group of receptors comprises the transmembrane pathogen- or pattern-recognition receptors (PRRs), which respond to slowly evolving pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs). The second group of immune receptors is formed by the polymorphic disease resistance (R) proteins that detect microbe-derived effector proteins. Most R proteins are members of the nucleotide binding leucine-rich repeat (NB-LRR) class. Although this class comprises one of the biggest protein families in plants, relatively few have been functionally characterised to date. The question rises whether all NB-LRRs function as immune receptors, or that they might have alternative functions. The answer is: yes, they do have alternative functions that are different from the immune receptor function. This review summarises the current knowledge about non-immune receptor signal transduction functions of NB-LRRs in plants. 相似文献
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Crops resistant to insect attack offer an alternative strategy of pest control to a total reliance upon chemical pesticides. Transgenic plant technology can be a useful tool in producing resistant crops, by introducing novel resistance genes into a plant species. This technology is seen very much as forming an integral component of a crop management programme. Several different classes of plant proteins have been shown to be insecticidal towards a range of economically important insect pests from different orders; in some cases a role in the defence of specific plant species against phytophagous insects has been demonstrated. Genes encoding insecticidal proteins have been isolated from various plant species and transferred to crops by genetic engineering. Amongst these genes are those that encode inhibitors of proteases (serine and cysteine) and α-amylase, lectins, and enzymes such as chitinases and lipoxygenases. Examples of genetically engineered crops expressing insecticidal plant proteins from different plant species, with enhanced resistance to one or more insect pests from the orders Lepidoptera, Homoptera and Coleoptera are presented. The possibility of ‘pyramiding’ different resistance genes to improve the effectiveness of protection and durability is discussed and exemplified. The number of different crop species expressing such genes is very diverse and ever-increasing. The viability of this approach to crop protection is considered. © 1998 SCI. 相似文献