共查询到20条相似文献，搜索用时 15 毫秒
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Rakesh Santhanam Youngjoo Oh Ramesh Kumar Arne Weinhold Van Thi Luu Karin Groten Ian T. Baldwin 《Molecular ecology》2017,26(9):2543-2562
Plants recruit microbial communities from the soil in which they germinate. Our understanding of the recruitment process and the factors affecting it is still limited for most microbial taxa. We analysed several factors potentially affecting root microbiome structure – the importance of geographic location of natural populations, the microbiome of native seeds as putative source of colonization and the effect of a plant's response to UVB exposure on root colonization of highly abundant species. The microbiome of Nicotiana attenuata seeds was determined by a culture‐dependent and culture‐independent approach, and the root microbiome of natural N. attenuata populations from five different locations was analysed using 454‐pyrosequencing. To specifically address the influence of UVB light on root colonization by Deinococcus, a genus abundant and consistently present in N. attenuata roots, transgenic lines impaired in UVB perception (irUVR8) and response (irCHAL) were investigated in a microcosm experiment with/without UVB supplementation using a synthetic bacterial community. The seed microbiome analysis indicated that N. attenuata seeds are sterile. Alpha and beta diversities of native root bacterial communities differed significantly between soil and root, while location had only a significant effect on the fungal but not the bacterial root communities. With UVB supplementation, root colonization of Deinococcus increased in wild type, but decreased in irUVR8 and irCHAL plants compared to nontreated plants. Our results suggest that N. attenuata recruits a core root microbiome exclusively from soil, with fungal root colonization being less selective than bacterial colonization. Root colonization by Deinococcus depends on the plant's response to UVB. 相似文献
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Gisuk Lee Youngsung Joo Sang‐Gyu Kim Ian T. Baldwin 《The Plant journal : for cell and molecular biology》2017,92(3):414-425
Herbivore attack is known to elicit systemic defense responses that spread throughout the host plant and influence the performance of other herbivores. While these plant‐mediated indirect competitive interactions are well described, and the co‐existence of herbivores from different feeding guilds is common, the mechanisms of co‐existence are poorly understood. In both field and glasshouse experiments with a native tobacco, Nicotiana attenuata, we found no evidence of negative interactions when plants were simultaneously attacked by two spatially separated herbivores: a leaf chewer Manduca sexta and a stem borer Trichobaris mucorea. T. mucorea attack elicited jasmonic acid (JA) and jasmonoyl‐l ‐isoleucine bursts in the pith of attacked stems similar to those that occur in leaves when M. sexta attacks N. attenuata leaves. Pith chlorogenic acid (CGA) levels increased 1000‐fold to levels 6‐fold higher than leaf levels after T. mucorea attack; these increases in pith CGA levels, which did not occur in M. sexta‐attacked leaves, required JA signaling. With plants silenced in CGA biosynthesis (irHQT plants), CGA, as well as other caffeic acid conjugates, was demonstrated in both glasshouse and field experiments to function as a direct defense protecting piths against T. mucorea attack, but not against leaf chewers or sucking insects. T. mucorea attack does not systemically activate JA signaling in leaves, while M. sexta leaf‐attack transiently induces detectable but minor pith JA levels that are dwarfed by local responses. We conclude that tissue‐localized defense responses allow tissue‐specialized herbivores to share the same host and occupy different chemical defense niches in the same hostplant. 相似文献
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Saeed Hosseinzadeh Ebrahim Hosseinzadeh 《Archives Of Phytopathology And Plant Protection》2013,46(6):643-655
Ralstonia solanacearum is a complex bacterial species that causes the very destructive plant disease, bacterial wilt, on many solanaceous species and also several other plant families in tropical, subtropical and some temperate regions of the world. In this study, the inhibitory effects of three sub-bactericidal concentrations of the Cinnamon (Cinnamomum zeylanicum), Thyme (Thymus vulgaris), lavender (Lavandula angustifolia) and eucalyptus (Eucalyptus camaldulensis) essential oils (EOs) were evaluated on biofilm formation, the swimming, swarming and twitching motilities of R. solanacearum race three strains. Furthermore, the effects of EOs on bacterial morphology were assessed. All treatments caused significant reductions in biofilm formation and on the ability to swim, swarm and twitch of bacterial cells. The results also indicated that sub-lethal concentrations of EOs which were applied in this study caused abnormality in the shape of bacterial cells and changed the R. solanacearum morphology. The results obtained indicated that the sub-bactericidal concentrations of EOs applied in this study suppressed R. solanacearum pathogenicity and virulence factors. Because of less phytotoxicity at these concentrations and lower costs of their application, they can be used as environment-friendly biofumigants. 相似文献
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Isolation of Ralstonia solanacearum‐infecting bacteriophages from tomato fields in Chiang Mai,Thailand, and their experimental use as biocontrol agents 
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下载免费PDF全文 A. Bhunchoth N. Phironrit C. Leksomboon O. Chatchawankanphanich S. Kotera E. Narulita T. Kawasaki M. Fujie T. Yamada 《Journal of applied microbiology》2015,118(4):1023-1033
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Péninna Deberdt Eric Gozé Régine Coranson‐Beaudu Benjamin Perrin Paula Fernandes Philippe Lucas Alain Ratnadass 《Journal of Phytopathology》2015,163(5):377-385
Ralstonia solanacearum is responsible for bacterial wilt affecting many crops worldwide. The emergent population of R. solanacearum (phylotype IIB/4NPB) wilts previously resistant varieties and has rapidly spread throughout Martinique. No conventional method is known to control it. In this study, previous crops used as sanitizing crops were investigated as an environmentally safe alternative method of control. The ability of the emergent population of R. solanacearum to persist in planta and in the rhizosphere of Brassicaceae, Asteraceae and Fabaceae grown as previous crops was evaluated in controlled conditions, and the incidence of bacterial wilt was assessed in the following tomato crop. Results showed that all species carried R. solanacearum latently. Among Brassicaceae and Asteraceae, the highest density of R. solanacearum was found in planta and in the rhizosphere of Tagetes erecta. The density of the R. solanacearum population in the rhizosphere of Raphanus sativus cv. Karacter was significantly higher than that in Raphanus sativus cv. Melody. In Fabaceae, the density of R. solanacearum population in planta was statistically similar in all species. The density of the R. solanacearum population in the rhizosphere of Crotalaria juncea was significantly higher than that in Crotalaria spectabilis. This study showed for the first time that Crotalaria spectabilis and Raphanus sativus cv. Melody grown as previous crops improve the performance of the following tomato with similar effects on R. solanacearum populations in the soil as bare soil. The incidence of the disease in tomato decreased by 86% and 60%, after R. sativus cv. Melody and C. spectabilis, respectively, and the proportion of infected plants also decreased. These results suggest that C. spectabilis and R. sativus cv. Melody can be used as previous crops to help bacterial wilt control in ecological management strategies without drastic suppression of R. solanacearum population in stem tissues and in the rhizosphere. 相似文献
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Gisuk Lee Youngsung Joo Celia Diezel Eun Ju Lee Ian T. Baldwin Sang‐Gyu Kim 《Molecular ecology》2016,25(14):3509-3519
Herbivorous insects use plant metabolites to inform their host plant selection for oviposition. These host‐selection behaviours are often consistent with the preference–performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. However, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically relevant interactions. Here, we examined the host‐selection behaviours of two sympatric weevils, the Datura (Trichobaris compacta) and tobacco (T. mucorea) weevils in field and glasshouse experiments with transgenic host plants specifically altered in different components of their secondary metabolism. Adult females of both species strongly preferred to feed on D. wrightii rather than on N. attenuata leaves, but T. mucorea preferred to oviposit on N. attenuata, while T. compacta oviposited only on D. wrightii. These oviposition behaviours increased offspring performance: T. compacta larvae only survived in D. wrightii stems and T. mucorea larvae survived better in N. attenuata than in D. wrightii stems. Choice assays with nicotine‐free, JA‐impaired, and sesquiterpene‐over‐produced isogenic N. attenuata plants revealed that although half of the T. compacta larvae survived in nicotine‐free N. attenuata lines, nicotine did not influence the oviposition behaviours of both the nicotine‐adapted and nicotine‐sensitive species. JA‐induced sesquiterpene volatiles are key compounds influencing T. mucorea females’ oviposition choices, but these sesquiterpenes had no effect on larval performance. We conclude that adult females are able to choose the best host plant for their offspring and use chemicals different from those that influence larval performance to inform their oviposition decisions. 相似文献
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Mario Kallenbach Youngjoo Oh Elisabeth J. Eilers Daniel Veit Ian T. Baldwin Meredith C. Schuman 《The Plant journal : for cell and molecular biology》2014,78(6):1060-1072
Plant volatiles (PVs) mediate interactions between plants and arthropods, microbes and other plants, and are involved in responses to abiotic stress. PV emissions are therefore influenced by many environmental factors, including herbivore damage, microbial invasion, and cues from neighboring plants, and also light regime, temperature, humidity and nutrient availability. Thus, an understanding of the physiological and ecological functions of PVs must be based on measurements reflecting PV emissions under natural conditions. However, PVs are usually sampled in the artificial environments of laboratories or climate chambers. Sampling of PVs in natural environments is difficult, being limited by the need to transport, maintain and provide power to instruments, or use expensive sorbent devices in replicate. Ideally, PVs should be measured in natural settings with high replication, spatio‐temporal resolution and sensitivity, and modest costs. Polydimethylsiloxane (PDMS), a sorbent commonly used for PV sampling, is available as silicone tubing for as little as 0.60 € m?1 (versus 100–550 € each for standard PDMS sorbent devices). Small pieces of silicone tubing (STs) of various lengths from millimeters to centimeters may be added to any experimental setting and used for headspace sampling, with little manipulation of the organism or headspace. STs have sufficiently fast absorption kinetics and large capacity to sample plant headspaces over a timescale of minutes to hours, and thus can produce biologically meaningful ‘snapshots’ of PV blends. When combined with thermal desorption coupled to GC–MS (a 40‐year‐old widely available technology), use of STs yields reproducible, sensitive, spatio‐temporally resolved quantitative data from headspace samples taken in natural environments. 相似文献
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Xue‐fang Zheng Yu‐jing Zhu Bo Liu You Zhou Jian‐mei Che Nai‐quan Lin 《Journal of Phytopathology》2014,162(9):607-616
A field survey was conducted to determine the relationship between Ralstonia solanacearum diversity and severity of bacterial wilt disease in tomato plants grown in plastic greenhouses. Both vegetative and reproductive stages of the plants were surveyed, and the symptoms were empirically categorized into five scales: 0 (asymptomatic): 1st, 2nd, 3rd and 4th. The bacterial wilt pathogen was isolated from infected plants at each disease scale; pathogenic characteristics and population densities of the bacterial strains were assessed. Two hundred and eighty‐two isolates were identified as R. solanacearum, which were divided into three pathogenic types, virulent, avirulent and interim, using the attenuation index (AI) method and a plant inoculation bioassay. Ralstonia solanacearum was detected in all asymptomatic and symptomatic tomato plants, with population numbers, ranging from 10.5 to 86.7 × 105 cfu/g. However, asymptomatic plants harboured only avirulent or interim R. solanacearum, whereas tomato plants displaying 1st or 2nd disease degree contained interim and virulent strains. Additionally, 3rd and 4th degree plants harboured only virulent strains. The disease was more severe in vegetative‐stage plants (disease severity index (DSI) 0.20) with higher total numbers of interim and virulent R. solanacearum strains than those in reproductive‐stage plants (DSI 0.12). Three pathotypes of R. solanacearum coexisted in a competitive growth system in the tomato field, and their distribution closely correlated with the severity of tomato bacterial wilt. 相似文献
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Martin Schäfer Christoph Brütting Klaus Gase Michael Reichelt Ian Baldwin Stefan Meldau 《The Plant journal : for cell and molecular biology》2013,76(3):506-518
Field experiments with transgenic plants often reveal the functional significance of genetic traits that are important for the performance of the plants in their natural environments. Until now, only constitutive overexpression, ectopic expression and gene silencing methods have been used to analyze gene‐related phenotypes in natural habitats. These methods do not allow sufficient control over gene expression for the study of ecological interactions in real time, of genetic traits that play essential roles in development, or of dose‐dependent effects. We applied the sensitive dexamethasone (DEX)‐inducible pOp6/LhGR expression system to the ecological model plant Nicotiana attenuata and established a lanolin‐based DEX application method to facilitate ectopic gene expression and RNA interference‐mediated gene silencing in the field and under challenging conditions (e.g. high temperature, wind and UV radiation). Fully established field‐grown plants were used to silence phytoene desaturase and thereby cause photobleaching only in specific plant sectors, and to activate expression of the cytokinin (CK) biosynthesis gene isopentenyl transferase (ipt). We used ipt expression to analyze the role of CKs in both the glasshouse and the field to understand resistance to the native herbivore Tupiocoris notatus, which attacks plants at small spatial scales. By spatially restricting ipt expression and elevating CK levels in single leaves, damage by T. notatus increased, demonstrating the role of CKs in this plant–herbivore interaction at a small scale. As the arena of most ecological interactions is highly constrained in time and space, these tools will advance the genetic analysis of dynamic traits that matter for plant performance in nature. 相似文献
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Christoph Brütting Martin Schäfer Radomíra Vanková Klaus Gase Ian T. Baldwin Stefan Meldau 《The Plant journal : for cell and molecular biology》2017,89(1):15-30
Plant defense metabolites are well known to be regulated developmentally. The optimal defense (OD) theory posits that a tssue's fitness values and probability of attack should determine defense metabolite allocations. Young leaves are expected to provide a larger fitness value to the plant, and therefore their defense allocations should be higher when compared with older leaves. The mechanisms that coordinate development with defense remain unknown and frequently confound tests of the OD theory predictions. Here we demonstrate that cytokinins (CKs) modulate ontogeny‐dependent defenses in Nicotiana attenuata. We found that leaf CK levels highly correlate with inducible defense expressions with high levels in young and low levels in older leaves. We genetically manipulated the developmental patterns of two different CK classes by using senescence‐ and chemically inducible expression of CK biosynthesis genes. Genetically modifying the levels of different CKs in leaves was sufficient to alter ontogenic patterns of defense metabolites. We conclude that the developmental regulation of growth hormones that include CKs plays central roles in connecting development with defense and therefore in establishing optimal patterns of defense allocation in plants. 相似文献
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Naiem Husien Al‐Husien Aladdin Hamwieh Seid Ahmed Bassam Bayaa 《Journal of Phytopathology》2017,165(5):306-312
Lentil (Lens culinaris Medik.) is an important food legume crop in Syria. Fusarium wilt (Fusarium oxysporum f.sp. lentis – Fol) is a key yield‐limiting factor in the country. The genetic diversity of Fol population was studied using 96 isolates collected from different parts of the country using molecular markers. A total of 16 markers, random amplified polymorphic DNA, simple sequence repeats and inter‐simple sequence repeats were used and 218 polymorphic markers (scorable bands) were obtained. Cluster and structure analyses grouped the isolates into three major groups and subgroups indicating high genetic diversity in the pathogen populations. The molecular variance within the population accounted 87% of the total variation indicating high diversity within population than among geographic locations. The result of this study showed that no alleles were linked to specific province, and therefore, screening for the Fusarium wilt in one location using virulent isolates could be enough to save time and resources. 相似文献
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Type VI secretion system MIX‐effectors carry both antibacterial and anti‐eukaryotic activities 下载免费PDF全文
下载免费PDF全文 Ann Ray Nika Schwartz Marcela de Souza Santos Junmei Zhang Kim Orth Dor Salomon 《EMBO reports》2017,18(11):1978-1990
Most type VI secretion systems (T6SSs) described to date are protein delivery apparatuses that mediate bactericidal activities. Several T6SSs were also reported to mediate virulence activities, although only few anti‐eukaryotic effectors have been described. Here, we identify three T6SSs in the marine bacterium Vibrio proteolyticus and show that T6SS1 mediates bactericidal activities under warm marine‐like conditions. Using comparative proteomics, we find nine potential T6SS1 effectors, five of which belong to the polymorphic MIX‐effector class. Remarkably, in addition to six predicted bactericidal effectors, the T6SS1 secretome includes three putative anti‐eukaryotic effectors. One of these is a MIX‐effector containing a cytotoxic necrotizing factor 1 domain. We demonstrate that T6SS1 can use this MIX‐effector to target phagocytic cells, resulting in morphological changes and actin cytoskeleton rearrangements. In conclusion, the V. proteolyticus T6SS1, a system homologous to one found in pathogenic vibrios, uses a suite of polymorphic effectors that target both bacteria and eukaryotic neighbors. 相似文献
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Sven Heiling Santosh Khanal Aiko Barsch Gabriela Zurek Ian T. Baldwin Emmanuel Gaquerel 《The Plant journal : for cell and molecular biology》2016,85(4):561-577
Exploring the diversity of plant secondary metabolism requires efficient methods to obtain sufficient structural insights to discriminate previously known from unknown metabolites. De novo structure elucidation and confirmation of known metabolites (dereplication) remain a major bottleneck for mass spectrometry‐based metabolomic workflows, and few systematic dereplication strategies have been developed for the analysis of entire compound classes across plant families, partly due to the complexity of plant metabolic profiles that complicates cross‐species comparisons. 17‐hydroxygeranyllinalool diterpene glycosides (HGL‐DTGs) are abundant defensive secondary metabolites whose malonyl and glycosyl decorations are induced by jasmonate signaling in the ecological model plant Nicotiana attenuata. The multiple labile glycosidic bonds of HGL‐DTGs result in extensive in‐source fragmentation (IS‐CID) during ionization. To reconstruct these IS‐CID clusters from profiling data and identify precursor ions, we applied a deconvolution algorithm and created an MS/MS library from positive‐ion spectra of purified HGL‐DTGs. From this library, 251 non‐redundant fragments were annotated, and a workflow to characterize leaf, flower and fruit extracts of 35 solanaceous species was established. These analyses predicted 105 novel HGL‐DTGs that were restricted to Nicotiana, Capsicum and Lycium species. Interestingly, malonylation is a highly conserved step in HGL‐DTG metabolism, but is differentially affected by jasmonate signaling among Nicotiana species. This MS‐based workflow is readily applicable for cross‐species re‐identification/annotation of other compound classes with sufficient fragmentation knowledge, and therefore has the potential to support hypotheses regarding secondary metabolism diversification. 相似文献
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Marta L. del Campo Rayko Halitschke Sarah M. Short Brian P. Lazzaro André Kessler 《Entomologia Experimentalis et Applicata》2013,146(3):321-331
Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here, we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogenic acid (CA), and other caffeic acid derivatives as they feed on one of their hosts, Nicotiana attenuata L. (Solanaceae), and on artificial diet supplemented with CA. We test the hypothesis that larvae fed on CA‐supplemented diet would have better resistance against bacterial infection than larvae fed on a standard CA‐free diet by injecting bacteria into the hemocoel of fourth instars. Larvae fed CA‐supplemented diet show significantly higher survival of infection with Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper‐Bälz, but not of infection with the more virulent Pseudomonas aeruginosa (Schroeter) Migula. Larvae fed on CA‐supplemented diet possess a constitutively higher number of circulating hemocytes than larvae fed on the standard diet, but we found no other evidence of increased immune system activity, nor were larvae fed on CA‐supplemented diet better able to suppress bacterial proliferation early in the infection. Thus, our data suggest an additional defensive function of CA to the direct toxic inhibition of pathogen proliferation in the gut. 相似文献
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Simon Renny‐Byfield Ales Kovarik Laura J. Kelly Jiri Macas Petr Novak Mark W. Chase Richard A. Nichols Mahesh R. Pancholi Marie‐Angele Grandbastien Andrew R. Leitch 《The Plant journal : for cell and molecular biology》2013,74(5):829-839
Recent advances have highlighted the ubiquity of whole‐genome duplication (polyploidy) in angiosperms, although subsequent genome size change and diploidization (returning to a diploid‐like condition) are poorly understood. An excellent system to assess these processes is provided by Nicotiana section Repandae, which arose via allopolyploidy (approximately 5 million years ago) involving relatives of Nicotiana sylvestris and Nicotiana obtusifolia. Subsequent speciation in Repandae has resulted in allotetraploids with divergent genome sizes, including Nicotiana repanda and Nicotiana nudicaulis studied here, which have an estimated 23.6% genome expansion and 19.2% genome contraction from the early polyploid, respectively. Graph‐based clustering of next‐generation sequence data enabled assessment of the global genome composition of these allotetraploids and their diploid progenitors. Unexpectedly, in both allotetraploids, over 85% of sequence clusters (repetitive DNA families) had a lower abundance than predicted from their diploid relatives; a trend seen particularly in low‐copy repeats. The loss of high‐copy sequences predominantly accounts for the genome downsizing in N. nudicaulis. In contrast, N. repanda shows expansion of clusters already inherited in high copy number (mostly chromovirus‐like Ty3/Gypsy retroelements and some low‐complexity sequences), leading to much of the genome upsizing predicted. We suggest that the differential dynamics of low‐ and high‐copy sequences reveal two genomic processes that occur subsequent to allopolyploidy. The loss of low‐copy sequences, common to both allopolyploids, may reflect genome diploidization, a process that also involves loss of duplicate copies of genes and upstream regulators. In contrast, genome size divergence between allopolyploids is manifested through differential accumulation and/or deletion of high‐copy‐number sequences. 相似文献