Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.300
Filtrar
1.
Microbiol Spectr ; 10(1): e0057721, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35107322

RESUMO

In summer 2019, widespread occurrence of crown gall disease caused by Agrobacterium spp. was observed on commercially grown ornamental plants in southern Iran. Beside agrobacteria, pale yellow-pigmented Gram-negative strains resembling the members of Xanthomonas were also associated with crown gall tissues on weeping fig (Ficus benjamina) and Amaranthus sp. plants. The purpose of the present study was to characterize the crown gall-associated Xanthomonas strains using plant inoculation assays, molecular-phylogenetic analyses, and comparative genomics approaches. Pathogenicity tests showed that the Xanthomonas strains did not induce disease symptoms on their host of isolation. However, the strains induced hypersensitive reaction on tobacco, geranium, melon, squash, and tomato leaves via leaf infiltration. Multilocus sequence analysis suggested that the strains belong to clade IA of Xanthomonas, phylogenetically close to Xanthomonas translucens, X. theicola, and X. hyacinthi. Average nucleotide identity and digital DNA-DNA hybridization values between the whole-genome sequences of the strains isolated in this study and reference Xanthomonas strains are far below the accepted thresholds for the definition of prokaryotic species, signifying that these strains could be defined as two new species within clade IA of Xanthomonas. Comparative genomics showed that the strains isolated from crown gall tissues are genetically distinct from X. translucens, as almost all the type III secretion system genes and type III effectors are lacking in the former group. The data obtained in this study provide novel insight into the breadth of genetic diversity of crown gall-associated bacteria and pave the way for research on gall-associated Xanthomonas-plant interactions. IMPORTANCE Tumorigenic agrobacteria-members of the bacterial family Rhizobiaceae-cause crown gall and hairy root diseases on a broad range of plant species. These bacteria are responsible for economic losses in nurseries of important fruit trees and ornamental plants. The microclimate of crown gall and their accompanying microorganisms has rarely been studied for the microbial diversity and population dynamics of gall-associated bacteria. Here, we employed a series of biochemical tests, pathogenicity assays, and molecular-phylogenetic analyses, supplemented with comparative genomics, to elucidate the biological features, taxonomic position, and genomic repertories of five crown gall-associated Xanthomonas strains isolated from weeping fig and Amaranthus sp. plants in Iran. The strains investigated in this study induced hypersensitive reactions (HR) on geranium, melon, squash, tobacco, and tomato leaves, while they were nonpathogenic on their host of isolation. Phylogenetic analyses and whole-genome-sequence-based average nucleotide identity (ANI)/digital DNA-DNA hybridization (dDDH) calculations suggested that the Xanthomonas strains isolated from crown gall tissues belong to two taxonomically unique clades closely related to the clade IA species of the genus, i.e., X. translucens, X. hyacinthi, and X. theicola.


Assuntos
Filogenia , Tumores de Planta/microbiologia , Xanthomonas/classificação , Xanthomonas/genética , Amaranthus/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Ficus/microbiologia , Variação Genética , Genoma Bacteriano , Genômica , Fenótipo , Raízes de Plantas/microbiologia , Xanthomonas/isolamento & purificação , Xanthomonas/metabolismo
2.
Plant Biol (Stuttg) ; 24(3): 450-457, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35098632

RESUMO

Eremanthus erythropappus hosts globoid stem galls induced by Neolasioptera sp. (Diptera: Cecidomyiidae) close to the stem apex, which do not compromise the shoot apical meristem (SAM). We hypothesize that maintenance of the SAM, as well as the increasing number of leaves per branch and of galled stem lengths and diameters, are a consequence of alterations in vascular cells and, consequently, in the priority for water flow from non-galled stems to the stem galls. Our study focuses on the globoid stem galls to evaluate if gall induction and development promote changes in structure and function of secondary xylem cells. Anatomical, cytological, histometric and physiological methods were used to analyse non-galled stem branches (NGS), mature globoid stem galls and stem portions below and above the galls. These analyses revealed that vessel elements are larger in stem galls and in stem portions above the galls. Under Neolasioptera sp. induction activity, the vascular cambium of E. erythropappus produces less numerous but larger vessel elements and overproduces parenchyma cells. Contrary to the vascular constriction hypothesis proposed for bacterial galls, the vascular traits of the Neolasioptera sp. stem galls on E. erythropappus result in priority for water flow to galls and the non-galled portions above the galls, allowing the maintenance of galled stem growth and development.


Assuntos
Asteraceae , Dípteros , Animais , Meristema , Folhas de Planta , Tumores de Planta , Madeira
3.
Pest Manag Sci ; 78(4): 1721-1728, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34997819

RESUMO

BACKGROUND: Here, we investigated changes in primary metabolism and cell death around oviposition sites in two hybrid clones of Eucalyptus with different degrees of resistance to Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae), as well as tolerance to water deficiency. RESULTS: We showed that apices of the resistant clone with oviposition had a higher content of amino acids, organic acids and the compound putrescine compared with those of the susceptible clone with oviposition. By contrast, apices of the resistant clone with oviposition had lower sugar and pyruvate organic acid content than those of the susceptible clone with oviposition. Small areas of necrosis were induced around the oviposition sites in the stem apices of Eucalyptus 24 h after infestation. The resistant clone developed larger necrotic areas that showed progressive increases 24-72 h after infestation compared with the susceptible clone, in which cell death was significantly lower and no changes were observed in necrotic area over time. Thus, the programmed death of cells around the egg, modulated by several amino acids, is likely the first defence response of Eucalyptus against L. invasa. CONCLUSION: Our results serve as the basis for the early identification of key metabolites produced in plants in defence against galling insects. © 2022 Society of Chemical Industry.


Assuntos
Eucalyptus , Vespas , Animais , Morte Celular , Feminino , Oviposição , Tumores de Planta , Vespas/fisiologia
4.
Mol Phylogenet Evol ; 169: 107388, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35017066

RESUMO

Tumor-inducing (Ti) and root-inducing (Ri) plasmids of Agrobacterium that display a large diversity are involved in crown gall and hairy root plant diseases. Their phylogenetic relationships were inferred from an exhaustive set of Ti and Ri plasmids (including 36 new complete Ti plasmids) by focusing on T-DNA and virulence regions. The opine synthase gene content of T-DNAs revealed 13 opine types corresponding to former classifications based on opines detected in diseased plants, while the T-DNA gene content more finely separate opine types in 18 T-DNA organizations. This classification was supported by the phylogeny of T-DNA oncogenes of Ti plasmids. The five gene organizations found in Ti/Ri vir regions was supported by the phylogeny of common vir genes. The vir organization was found to be likely an ancestral plasmid trait separating "classic" Ti plasmids (with one or two T-DNAs) and "Ri and vine-Ti" plasmids. A scenario generally supported by the repABC phylogeny. T-DNAs likely evolved later with the acquisition of opine characteristics as last steps in the Ti/Ri plasmid evolution. This novel evolutionary classification of Ti/Ri plasmids was found to be relevant for accurate crown gall and hairy root epidemiology.


Assuntos
Neoplasias , Rhizobium , DNA Bacteriano/genética , Humanos , Filogenia , Tumores de Planta/genética , Plasmídeos/genética , Rhizobium/genética , Virulência/genética
5.
Molecules ; 27(1)2022 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-35011511

RESUMO

FT-Raman, FTIR, and SERS spectra of the structurally related gallnut polyphenols tannic acid, gallic acid, pyrogallol, and syringic acid are reported in this work aiming at performing a comparative assignation of the bands and finding specific marker features that can identify these compounds in complex polyphenol mixtures. Tannic and gallic acids are the principal components in oak gallnuts, and they can be found in iron gall inks. The different functional groups existing in these molecules and their spatial distribution lead to slight changes of the vibrations. The Raman spectra are dominated by bands corresponding to the ring vibrations, but the substituents in the ring strongly affect these vibrations. In contrast, the FTIR spectra of these molecules are dominated by the peripheral oxygen-containing substituents of the aromatic ring and afford complementary information. SERS spectroscopy can be used to analyze trace amounts of these compounds, but the spectra of these polyphenols show strong changes in comparison with the Raman spectra, indicating a strong interaction with the metal. The most significant modification observed in the SERS spectra of these compounds is the weakening of the benzene 8a ring vibration and the subsequent intensification of the 19a mode of the benzene ring. This mode is also more intense in the FTIR spectra, and its intensification in the SERS spectra could be related to a drastic change in the molecular polarizability associated with the interaction of the polyphenol with the metal in Ag NPs.


Assuntos
Tumores de Planta , Polifenóis/química , Quercus/química , Análise Espectral Raman
6.
New Phytol ; 233(2): 905-918, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655498

RESUMO

Agrobacterium tumefaciens colonizes the galls (plant tumors) it causes, and the roots of host and nonhost plants. Transposon-sequencing (Tn-Seq) was used to discover A.tumefaciens genes involved in reproductive success (fitness genes) on Solanum lycopersicum and Populus trichocarpa tumors and S.lycopersicum and Zea mays roots. The identified fitness genes represent 3-8% of A. tumefaciens genes and contribute to carbon and nitrogen metabolism, synthesis and repair of DNA, RNA and proteins and envelope-associated functions. Competition assays between 12 knockout mutants and wild-type confirmed the involvement of 10 genes (trpB, hisH, metH, cobN, ntrB, trxA, nrdJ, kamA, exoQ, wbbL) in A.tumefaciens fitness under both tumor and root conditions. The remaining two genes (fecA, noxA) were important in tumors only. None of these mutants was nonpathogenic, but four (hisH, trpB, exoQ, ntrB) exhibited impaired virulence. Finally, we used this knowledge to search for chemical and biocontrol treatments that target some of the identified fitness pathways and report reduced tumorigenesis and impaired establishment of A.tumefaciens on tomato roots using tannic acid or Pseudomonas protegens, which affect iron assimilation. This work revealed A.tumefaciens pathways that contribute to its competitive survival in plants and highlights a strategy to identify plant protection approaches against this pathogen.


Assuntos
Agrobacterium tumefaciens , Lycopersicon esculentum , Agrobacterium tumefaciens/genética , Carbono , Lycopersicon esculentum/genética , Lycopersicon esculentum/microbiologia , Raízes de Plantas/genética , Tumores de Planta/genética , Tumores de Planta/microbiologia , Virulência/genética
8.
Protoplasma ; 259(1): 155-162, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33907892

RESUMO

Gall cytological, metabolic, and structural traits are established due to the feeding habits of the associated galling herbivores, and sometimes are influenced by other organisms involved in the interaction. We tested this assumption on three gall morphotypes, the globoid, the lenticular, and the fusiform, induced by Cecidomyiidae on leaflets of Inga ingoides (Rich.) Willd. (Fabaceae: Caesalpinioideae). Taking for granted that the three Cecidomyiidae galls are induced on the same host plant and organ, we assume that the cytological and histochemical traits of their nutritive cells may be similar, but under the fungi influence, the ambrosia gall cytological profile may be peculiar and reflect on the accumulation of primary metabolites. The ambrosia globoid galls involve three organisms (host plant, gall inducer, and fungi), while the fusiform and the lenticular galls involve two organisms (host plant and gall inducer). The accumulation of primary metabolites is similar among the three gall morphotypes, except for the non-detection of reducing sugars in the fusiform galls. The fungi presence can impact the system but does not define exclusive features for the ambrosia globoid galls when compared to the lenticular and fusiform morphotypes. In fact, the cytological traits have revealed three different cytological mechanisms for food resources availability to the three galling Cecidomyiidae: (a) cell wall destructuring and cell death by fungi intermediation in the ambrosia globoid galls, (b) necrosis-type cell death in the fusiform galls, and (c) maintenance of continuous metabolic activity in the lenticular galls.


Assuntos
Fabaceae , Tumores de Planta , Parede Celular , Herbivoria , Interações Hospedeiro-Parasita
9.
J Exp Bot ; 73(2): 555-570, 2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-34129033

RESUMO

Galling insects gain food and shelter by inducing specialized anatomical structures in their plant hosts. Such galls often accumulate plant defensive metabolites protecting the inhabiting insects from predation. We previously found that, despite a marked natural chemopolymorphism in natural populations of Pistacia palaestina, the monoterpene content in Baizongia pistaciae-induced galls is substantially higher than in leaves of their hosts. Here we show a general up-regulation of key structural genes in both the plastidial and cytosolic terpene biosynthetic pathways in galls as compared with non-colonized leaves. Novel prenyltransferases and terpene synthases were functionally expressed in Escherichia coli to reveal their biochemical function. Individual Pistacia trees exhibiting chemopolymorphism in terpene compositions displayed differential up-regulation of selected terpene synthase genes, and the metabolites generated by their gene products in vitro corresponded to the monoterpenes accumulated by each tree. Our results delineate molecular mechanisms responsible for the formation of enhanced monoterpene in galls and the observed intraspecific monoterpene chemodiversity displayed in P. palaestina. We demonstrate that gall-inhabiting aphids transcriptionally reprogram their host terpene pathways by up-regulating tree-specific genes, boosting the accumulation of plant defensive compounds for the protection of colonizing insects.


Assuntos
Afídeos , Pistacia , Animais , Tumores de Planta , Terpenos , Regulação para Cima
10.
Plant Sci ; 314: 111114, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34895543

RESUMO

Reactive oxygen species (ROS) are considered the first signaling molecules involved in gall development, linked to the establishment of cyto-histological gradients leading to gall tissue redifferentiation. ROS overproduction induces the failure of gall establishment or its premature senescence. Galls could therefore have efficient mechanisms of ROS dissipation and maintenance of homeostasis, such as polyphenol synthesis. The co-occurrence of ROS and polyphenols in the Espinosa nothofagi galls induced on Nothofagus obliqua buds was explored and was related to the antioxidant capacity of the inner (IC) and outer (OC) gall compartments. We hypothesize that: (i) ROS are produced and accumulated in both tissue compartments of E. nothofagi galls in co-occurrence with polyphenolic, flavonols, and lignin, conferring high antioxidant activity to inner and outer gall tissue compartment; (ii) antioxidant activity is higher in IC related to a higher polyphenol concentration in this compartment. The results show that ROS and polyphenols, mainly flavonols, are produced and accumulated in IC and OC, while lignin accumulated mainly in the IC. In both gall compartments, polyphenols mediate ROS elimination, confirmed by histochemical and spectrophotometry techniques. The IC extract has the highest antioxidant capacity, probably due to lignin deposition and a higher polyphenol concentration in this compartment.


Assuntos
Antioxidantes/metabolismo , Fagales/metabolismo , Fagales/parasitologia , Interações Hospedeiro-Parasita/efeitos dos fármacos , Insetos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fenóis/metabolismo , Tumores de Planta/parasitologia , Animais , Chile , Transdução de Sinais/efeitos dos fármacos
11.
Braz. j. biol ; 82: e236151, 2022. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1249247

RESUMO

Abstract Galls, neo-formed plant structures that can occur in different organs, are generated by species-specific interaction with an inducing organism. Inducers manipulate the metabolism of its host. Microgramma vacciniifolia (Langsd. & Fisch.) Copel. is a Neotropical epiphytic fern that hosted two stem galls, one induced by a midge species (Diptera) and other by a micromoth species (Lepidoptera). The aim of this study was to evaluate the impact of these two gall-inducing insects on the biochemistry of phenolic acids and the cyanogenesis in galls, stems and leaves of M. vacciniifolia. High performance liquid chromatography (HPLC) indicated a total of 14 phenol derivatives, including caffeic and coumaric acid. Principal Coordinates Analysis (PCoA) of the phenolic substances indicated three groups consisting (1) non-galled stems and micromoth-induced galls; (2) midge-induced galls; (3) midge-induced galls with parasitoids. Regarding the frequency of cyanogenesis assessed by the picrate paper test, the chi-squared test showed significant difference between fertile leaves (8.3%), sterile leaves (27.7%), non-galled stems (0%) and galls. Among galls, only the midge-induced galls analyzed were cyanogenic (15%). Our results indicated that the different gall-inducers (midge and micromoth) promote species-specific alterations to the phenolic substance composition of the host fern.


Resumo Galhas são estruturas vegetais neo-formadas que ocorrem em diferentes órgãos. Elas são geradas por uma interação espécie-específica com um organismo indutor. Os indutores manipulam o metabolismo do hospedeiro. Microgramma vacciniifolia (Langsd. & Fisch.) Copel. é uma samambaia epífita neotropical que hospeda duas galhas caulinares, uma induzida por uma espécie de mosquito (Diptera) e outra por uma micromariposa (Lepidoptera). O objetivo deste estudo foi avaliar o impacto desses dois insetos indutores de galhas na bioquímica dos ácidos fenólicos e da cianogênese em galhas, caules e folhas de M. vacciniifolia. Em análise de cromatografia líquida de alta eficiência (CLAE) foi possível indicar a presença de um total de 14 derivados fenólicos, incluindo ácido cafeico e ácido cumárico. Análise das Coordenadas Principais (ACoP) indicou três grupos (1) caules não galhados e galhas induzidas pela micromariposa; (2) galhas induzidas pelo mosquito; (3) galhas induzidas pelo mosquito com parasitoides. Em relação a frequência da cianogênese analisada com o teste do papel picrato, o teste do qui-quadrado apresentou diferença significativa entre as folhas férteis (8,3%), folhas estéreis (27,7%), caules não galhados (0%) e galhas. Entre as galhas, somente aquelas induzidas pelo mosquito foram cianogênicas (15%). Os resultados encontrados indicam, ao menos para as substâncias fenólicas, que os insetos indutores de galha (mosquito e micromariposa) promovem alterações espécie-específica na composição química da samambaia hospedeira.


Assuntos
Animais , Gleiquênias , Dípteros , Lepidópteros , Fenóis , Tumores de Planta , Folhas de Planta , Insetos
12.
Braz. j. biol ; 82: e235395, 2022. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1249236

RESUMO

Abstract Several records of associated fauna, including parasitoids, inquilines, predators, and successors, have been reported by insect gall inventories in Brazilian restingas. Although most guilds are well established, inquilines have frequently been misinterpreted. In this paper, the inquilinous fauna of insect galls is revised based on five criteria: food habit; coexistence with the inducer; modification of gall tissues or production of new tissues; phylogenetic relationship with the inducer; and mobility. Gall inventories dated from 1988 to 2019 were examined, totaling 16 publications, eight of them with inquiline records. This guild was reported in 53 gall morphotypes in 44 plant species and four morphospecies distributed among 36 genera of 24 host families for a total of 65 records. Most inquilines were repositioned into the cecidophage guild and others into the kleptoparasite guild, resulting in a large reduction in the frequency of inquilines (from 65 to five records), and in first reports of cecidophages and kleptoparasites, with 46 and 13 records, respectively. Cecidophage was the most diverse guild with insects of five orders (Diptera, Coleoptera, Lepidoptera, Hemiptera, and Thysanoptera) while kleptoparasites were represented only by two orders (Diptera and Hymenoptera) and inquiline solely by Hymenoptera. Other results indicate that Leptothorax sp. (Formicidae) could be a successor and not an inquiline.


Resumo Vários registros de fauna associada, incluindo parasitoides, inquilinos, predadores e sucessores são encontrados em inventários de galhas de insetos em restingas brasileiras. Embora a maioria das guildas esteja bem estabelecida, os inquilinos são frequentemente interpretados de forma equivocada. Nesse trabalho, a fauna inquilina de galhas de insetos é revisada com base em cinco critérios: hábito alimentar, coexistência com o indutor, modificação dos tecidos da galha ou produção de novos tecidos, relação filogenética com o indutor e mobilidade. Inventários de galhas publicados entre 1988 e 2019 foram examinados, totalizando 16 artigos, oito deles com registro de inquilinos. Essa guilda foi assinalada em 53 morfotipos de galhas em 44 espécies de plantas e quatro morfoespécies distribuídas em 36 gêneros de 24 famílias vegetais, totalizando 65 registros. A maioria dos inquilinos foi reposicionada na guilda dos cecidófagos e outros na guilda dos cleptoparasitas, resultando em uma grande redução da frequência dos inquilinos (de 65 para cinco registros), e na primeira ocorrência de cecidófagos e cleptoparasitas, com 46 e 13 registros, respectivamente. A guilda dos cecidófagos foi a mais diversa, com insetos de cinco ordens (Diptera, Coleoptera, Lepidoptera, Hemiptera e Thysanoptera), enquanto que os cleptoparasitas foram representados por apenas duas ordens (Diptera e Hymenoptera) e os inquilinos somente por Hymenoptera. Outros resultados indicam que Leptothorax sp. (Formicidae) pode ser um sucessor e não um inquilino.


Assuntos
Humanos , Animais , Tumores de Planta , Insetos , Filogenia , Plantas , Brasil , Interações Hospedeiro-Parasita
14.
Int J Mol Sci ; 22(22)2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34830140

RESUMO

The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.


Assuntos
Basidiomycota/genética , Resistência à Doença/genética , Perfilação da Expressão Gênica/métodos , Doenças das Plantas/genética , Tumores de Planta/genética , Poaceae/genética , Sequência de Aminoácidos , Basidiomycota/metabolismo , Basidiomycota/patogenicidade , Proteínas Fúngicas/classificação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno/genética , Hifas/genética , Hifas/metabolismo , Hifas/patogenicidade , Ácidos Indolacéticos/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Plantas/biossíntese , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Caules de Planta/genética , Caules de Planta/metabolismo , Caules de Planta/microbiologia , Tumores de Planta/microbiologia , Poaceae/metabolismo , Poaceae/microbiologia , Homologia de Sequência de Aminoácidos , Virulência/genética
15.
BMC Microbiol ; 21(1): 295, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34711172

RESUMO

BACKGROUND: The Agrobacterium strain AB2/73 has a unique host range for the induction of crown gall tumors, and contains an exceptionally large, over 500 kbp mega Ti plasmid. We used whole genome sequencing to fully characterize and comparatively analyze the complex genome of strain AB2/73, including its Ti plasmid and virulence factors. RESULTS: We obtained a high-quality, full genomic sequence of AB2/73 by a combination of short-read Illumina sequencing and long-read Nanopore sequencing. The AB2/73 genome has a total size of 7,266,754 bp with 59.5% GC for which 7012 genes (6948 protein coding sequences) are predicted. Phylogenetic and comparative genomics analysis revealed that strain AB2/73 does not belong to the genus Agrobacterium, but to a new species in the genus Rhizobium, which is most related to Rhizobium tropici. In addition to the chromosome, the genome consists of 6 plasmids of which the largest two, of more than 1 Mbp, have chromid-like properties. The mega Ti plasmid is 605 kbp in size and contains two, one of which is incomplete, repABC replication units and thus appears to be a cointegrate consisting of about 175 kbp derived from an unknown Ti plasmid linked to 430 kbp from another large plasmid. In pTiAB2/73 we identified a complete set of virulence genes and two T-DNAs. Besides the previously described T-DNA we found a larger, second T-DNA containing a 6b-like onc gene and the acs gene for agrocinopine synthase. Also we identified two clusters of genes responsible for opine catabolism, including an acc-operon for agrocinopine degradation, and genes putatively involved in ridéopine catabolism. The plasmid also harbours tzs, iaaM and iaaH genes for the biosynthesis of the plant growth regulators cytokinin and auxin. CONCLUSIONS: The comparative genomics analysis of the high quality genome of strain AB2/73 provided insight into the unusual phylogeny and genetic composition of the limited host range Agrobacterium strain AB2/73. The description of its unique genomic composition and of all the virulence determinants in pTiAB2/73 will be an invaluable tool for further studies into the special host range properties of this bacterium.


Assuntos
Genoma Bacteriano/genética , Filogenia , Plasmídeos/genética , Rhizobium/classificação , Rhizobium/genética , Agrobacterium/classificação , Agrobacterium/genética , Agrobacterium/patogenicidade , DNA Bacteriano , Genes Bacterianos , Genômica , Especificidade de Hospedeiro , Tumores de Planta/microbiologia , Replicon , Rhizobium/patogenicidade , Virulência/genética
16.
An Acad Bras Cienc ; 93(suppl 3): e20201442, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34586179

RESUMO

This study inventoried and characterized the richness of galling insects based on gall morphotypes and their host plants in two Cerrado sensu stricto areas of Caetité municipality in Bahia State, Brazil, to aid the identification of galling insects and their host plants, as well as to contribute to the knowledge and conservation of local biodiversity. The survey was conducted in the Moita dos Porcos archaeological site and João Barroca Farm site, adopting the random walking methodology for sampling, during 12 months. We recorded 98 gall morphotypes on 42 plant species belonging to 36 genera and 22 families. Leguminosae, Malpighiaceae and Myrtaceae demonstrated the greatest richness of galls, and the Copaifera langsdorffii was the super-host species, with 16 gall morphotypes. Most galls occur on leaves, and may be globoid, glabrous, grouped, and are usually unilocular, and brown. The galling insects identified belonged to Coleoptera, Diptera, Lepidoptera, and Thysanoptera. Eight plant host species and eight gall morphotypes were recorded for the first time in Cerrado areas in Brazil. The areas surveyed demonstrated high richness of gall morphotypes and host plants, evidencing the importance of studying and preserving different areas of the same biome.


Assuntos
Fabaceae , Interações Hospedeiro-Parasita , Animais , Brasil , Humanos , Insetos , Tumores de Planta
17.
Int J Mol Sci ; 22(17)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34502330

RESUMO

Galls are characteristic plant structures formed by cell size enlargement and/or cell proliferation induced by parasitic or pathogenic organisms. Insects are a major inducer of galls, and insect galls can occur on plant leaves, stems, floral buds, flowers, fruits, or roots. Many of these exhibit unique shapes, providing shelter and nutrients to insects. To form unique gall structures, gall-inducing insects are believed to secrete certain effector molecules and hijack host developmental programs. However, the molecular mechanisms of insect gall induction and development remain largely unknown due to the difficulties associated with the study of non-model plants in the wild. Recent advances in next-generation sequencing have allowed us to determine the biological processes in non-model organisms, including gall-inducing insects and their host plants. In this review, we first summarize the adaptive significance of galls for insects and plants. Thereafter, we summarize recent progress regarding the molecular aspects of insect gall formation.


Assuntos
Interações Hospedeiro-Parasita , Insetos/fisiologia , Tumores de Planta/etiologia , Plantas/parasitologia , Animais
18.
PLoS One ; 16(7): e0254193, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34288953

RESUMO

In recent years, the Asian gall wasp Dryocosmus kuriphilus has invaded chestnut trees and significantly affected the Portuguese chestnut production. Studies in other countries, such as Japan or Italy, have shown that the parasitoid Torymus sinensis can successfully achieve biological control of D. kuriphilus. Mathematical models help us to understand the dynamics of the interaction between the pest D. kuriphilus and its parasitoid T. sinensis and, consequently, they can help to implement measures that enhance crop pest management. In this work, the evolution of the density of D. kuriphilus and T. sinensis across time and space is studied through the numerical solution of models that include parameters based on observations made in Portugal. Simultaneous releases of the parasitoid are simulated at various locations and at different times. The results indicate that, in the case of a small and homogeneous orchard, biological control can be effective, but, in the case of extensive domains, the pest control is much more difficult to achieve. In order for biological control to be efficient, it is necessary to implement, in each chestnut-producing region, a collective strategy based on the annual monitoring of infestation levels.


Assuntos
Fagaceae/parasitologia , Modelos Teóricos , Controle Biológico de Vetores/métodos , Tumores de Planta/parasitologia , Vespas/parasitologia , Animais , Simulação por Computador , Larva/parasitologia , Estágios do Ciclo de Vida , Controle Biológico de Vetores/estatística & dados numéricos , Densidade Demográfica , Portugal , Pupa , Estações do Ano , Vespas/crescimento & desenvolvimento
19.
An Acad Bras Cienc ; 93(2): e20190710, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34076035

RESUMO

A literature compilation was done to gather information about Cecidomyiidae galls on Clusiaceae in Brazil. Botanical names were verified in the site "Flora do Brasil" as well as data on plant distribution and origin. Two herbaria were visited in order to examine galled specimens of Clusiaceae and retrieve new locality records. Thirteen gall morphotypes have been recorded on three genera (Clusia, Garcinia, and Tovomita) and eight species. Clusia showed the greatest number of galled species. Tovomita brevistaminea is the super host species. Only three gallers, Parazalepidota clusiae, Clusiamyia granulosa and C. nitida, were identified at species level, which highlights how the taxonomy of the gall midges is still poorly known. The examination of galled exsiccates resulted in the expansion of their distribution area. The low gall richness as well as the low number of galled plants on Clusiaceae can be related to the presence of resinous sticky sap and waxy cuticle. The known occurrence of gallers associated with Clusiaceae is restricted to the Atlantic Forest as their host plants. The gallers distribution is less wide than that of the host plants, indicating that their geographic limits can be further extended.


Assuntos
Clusiaceae , Dípteros , Animais , Brasil , Interações Hospedeiro-Parasita , Insetos , Tumores de Planta
20.
Braz J Biol ; 82: e235395, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34105660

RESUMO

Several records of associated fauna, including parasitoids, inquilines, predators, and successors, have been reported by insect gall inventories in Brazilian restingas. Although most guilds are well established, inquilines have frequently been misinterpreted. In this paper, the inquilinous fauna of insect galls is revised based on five criteria: food habit; coexistence with the inducer; modification of gall tissues or production of new tissues; phylogenetic relationship with the inducer; and mobility. Gall inventories dated from 1988 to 2019 were examined, totaling 16 publications, eight of them with inquiline records. This guild was reported in 53 gall morphotypes in 44 plant species and four morphospecies distributed among 36 genera of 24 host families for a total of 65 records. Most inquilines were repositioned into the cecidophage guild and others into the kleptoparasite guild, resulting in a large reduction in the frequency of inquilines (from 65 to five records), and in first reports of cecidophages and kleptoparasites, with 46 and 13 records, respectively. Cecidophage was the most diverse guild with insects of five orders (Diptera, Coleoptera, Lepidoptera, Hemiptera, and Thysanoptera) while kleptoparasites were represented only by two orders (Diptera and Hymenoptera) and inquiline solely by Hymenoptera. Other results indicate that Leptothorax sp. (Formicidae) could be a successor and not an inquiline.


Assuntos
Insetos , Tumores de Planta , Animais , Brasil , Interações Hospedeiro-Parasita , Humanos , Filogenia , Plantas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...