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At least 19 recordsLinked to original sources
PubMed1996

Translocation and exudation of tumor metabolites in crown galled plants.

Crown gall tumors are induced on susceptible plants by pathogenic strains of Agrobacterium. These neoplastic plants cells produce metabolites, called opines, which provide a source of nutrients to colonizing agrobacteria. Opine production previously has been shown to influence microbial communities in the immediate vicinity of the tumor. We have obtained evidence for opine translocation to and exudation from distal uninfected regions of the plant host. Grafted plants made from an opine-producing transgenic scion with a wild-type stock, or with a wild-type scion and an opine-producing stock accumulate opines in the wild-type portions of the plant. Moreover, opines were detected in root, stem, and leaf tissues of nontransgenic plants on which stem crown galls had been induced by pathogenic strains of Agrobacterium. These plants exuded opines from their roots as a component of their root exudates. Translocation of opines from the tumor to other parts of the plant, and their exudation from roots, indicates that these biologically active compounds are available to opine-catabolizing microbes that have not induced the tumors but are present in the rhizosphere or on portions of the plant distant from the site of the gall.

Biological Transport↗
PubMedDate not supplied

Grown gall plant tumors of abnormal morphology, induced by Agrobacterium tumefaciens carrying mutated octopine Ti plasmids; analysis of T-DNA functions.

Ti plasmid mutants derived from Agrobacterium tumefaciens strain Ach5 that induce tumors of abnormal morphology have been analyzed. On tobacco, A. tumefaciens mutant strain LBA4060 induces tumors that specifically give rise to shoots. Shoots continue to grow from in vitro cultured bacteria-free tumor tissue derived from such tumors. The mutant character is shown to be correlated with the insertion of an A. tumefaciens IS element, IS60, into the left arm of the T-region of the octopine Ti plasmid. Evidence is presented showing that IS60 is transferred into the plant cell DNA as part of the T-DNA. A second Ti plasmid insertion mutant A. tumefaciens strain LBA4210, with a Tn904 transposon in the center of the T-region, induces tumors that specifically exhibit a root development on tobacco plants. T-DNA has been detected in sterile amorphous crown-gall tissue derived from these tumors. The transposon Tn904 insertion was shown to result a changed "core" T-DNA. Abnormal tumor morphologies induced by these mutant strains have been observed also on Kalanchoë stems. On tomato plants the mutants induce small unorganized tumors while on Nicotiana rustica unorganized tumors, nearly equal in size to those caused by the wild-type strain have been induced. LBA4060 was shown to be avirulent on Kalanchoë leaves and LBA4210 was weakly virulent. Infection of Kalanchoë leaves or tomato plants with a mixture of separately grown cultures of both mutants resulted in the formation of more or less normal tumors. The exposure of a tomato plant to naphthalene acetic acid (NAA), a synthetic auxin, during development of tumors induced by LBA4060 stimulated tumor formation. Tumor growth induced by LBA4210 was found to be stimulated by kinetin.

Cloning, Molecular↗
PubMedDate not supplied

[Relationship between crown-gall plant tumors and the cell cycle].

It is established that under conditions of the culture in vitro the greatest amount of crown-gall swellings on topinambur and carrot explants is formed with Agrobacterium tumefaciens inoculation 4 and 6 hrs after the tissue extraction and planting, which corresponds to the G1-phase of the 1st cellular cycle. In the inoculated tissue cells entrance to the S-phase is accelerated and the maximal number of labelled nuclei is found 10 hrs earlier.

Helianthus↗
PubMed1983

Genetic analysis of T-DNA transcripts in nopaline crown galls.

Plant crown gall tumor cells result from the insertion and expression of a defined DNA sequence, called T-DNA, which is derived from the Ti plasmid, harbored by Agrobacterium tumefaciens strains. To study the function of the genes of the T-DNA of the nopaline Ti plasmid, pTiC58, a collection of mutants was isolated so that T-DNA genes are inactivated either separately or in various combinations. It was found that no single T-DNA gene or T-region border is absolutely essential for stable tumor formation. We have identified the gene responsible for synthesis in transformed cells of the phosphorylated sugar, agrocinopine, and at least three additional genes controlling the morphology of plant tumors. Two of these latter genes work together to inhibit shoot formation and ensure efficient tumorous growth. Inactivation of these genes can be suppressed by the addition of auxins. The third gene inhibits root formation and appears to play a role in the cytokinin-independent growth of transformed cells. Mutants missing all three genes do not induce tumors, nor shoot or root formation, although the mutant T-DNA sequence is transferred to plant cells.

Arginine↗
PubMed2002

Hydroponically cultivated radish fed L-galactono-1,4-lactone exhibit increased tolerance to ozone.

Leaf L-ascorbate content of an ozone (O3)-sensitive radish genotype (Raphanus sativus L. cv. Cherry Belle) was increased 2-fold by feeding hydroponically cultivated plants L-galactono- 1,4-lactone (GalL). Plants were grown in controlled-environment chambers ventilated with charcoal/Purafil-filtered air, and administered one of two O3 fumigation regimes: chronic exposure (75 nmol O3 mol(-1) for 7 h day(-1) for 21 days) and acute exposure (180 nmol O3 mol(-1) for 9 h). Chronic O3 exposure decreased root growth by 11% in plants maintained in pure nutrient solution (-GalL), but resulted in no change in root growth in GalL-fed plants (+GalL). Similarly, GalL-feeding counteracted the negative effects of O3 on CO2 assimilation rate observed in control plants (-GalL). Under acute O3 exposure, GalL-fed plants showed none of the visible symptoms of injury, which were extensive in plants not fed GalL. Leaf CO2 assimilation rate was decreased by acute 03 exposure in both GalL treatments, but the extent of the decline was less marked in GalL-fed plants. No significant changes in stomatal conductance resulted from GalL treatment, so O3 Uptake into leaves was equivalent in + GalL and -GalL plants. Feeding GalL, on the other hand, enhanced the level of ascorbate, and resulted in the maintenance of the redox state of ascorbate under acute O3 fumigation, in both the leaf apoplast and symplast. The effect of GalL treatment on ascorbate pools was consistent with the reduction in O3 damage observed in GalL-fed plants. Attempts to model O3 interception by the ascorbate pool in the leaf apoplast suggested a greater capacity for O3 detoxification in GalL-fed plants, which corresponded with the increase in O3 tolerance observed. However, modelled data for GalL-fed plants suggested that additional constituents of the leaf apoplast may play an important role in the attenuation of environmentally-relevant O3 fluxes.

Air Pollutants↗
PubMed2003

Crown gall -- a plant tumour with biological activities.

Petroleum ether, acetone, 80% MeOH and water extracts of crown gall, a plant tumour, obtained from Eucalyptus globulus tree were screened for cytotoxic, antioxidant, antiinflammatory, embryotoxic, antitumour-promoting and antimicrobial activities. In terms of bioactivity the 80% MeOH extract was most effective followed by the acetone extract. The petroleum ether extract showed weak to moderate cytotoxic activity in dose-dependent manner against PC12 cells, mouse L fibroblasts and 1321N1 glia cells, whereas the hydroalcohol extract had no or a weak cytotoxic effect. The 80% MeOH extract exhibited strong antioxidant activity. Based on the in vitro HET-CAM assay all the extracts were effective against inflammation. The extracts did not show any embryotoxic effect at the concentrations tested. Antitumour-promoting activity (100% inhibition; 100 microg/mL) was observed in the 80% MeOH and acetone extracts. In the antimicrobial screening all extracts displayed predominantly antifungal activity against Candida sp. The extracts also showed various levels of antibacterial activity against E. faecalis, Ps. aeruginosa, Bac. subtilis and Staph. epidermidis. From the results of the investigations it can be concluded that crown gall is a valuable plant tumour tissue having interesting biological activities.

Animals↗
PubMed2003

Galls on thistles.

Plant galls - the more we learn, the more there is to know! Approximately 15000 insect species ( c. 2% of all known insects) form galls, and this habit is extremely common over a range of floras and latitudes. Yet, there is still no general consensus on why they exist. Thistle-galling insects are relatively well known and are used as biological control agents (of thistles) and model ecological systems.

Animals↗
PubMed2004

Evolution of the gall-forming plant parasitic nematodes (Tylenchida: Anguinidae) and their relationships with hosts as inferred from Internal Transcribed Spacer sequences of nuclear ribosomal DNA.

Phylogenetic relationships among gall-forming plant parasitic nematodes of the subfamily Anguininae are reconstructed by maximum parsimony and maximum likelihood analyses. Sequences of the ITS of rDNA from 53 populations and species of gall-forming nematodes and five populations of the Ditylenchus dipsaci species complex were analysed. The phylogenetic trees strongly support monophyly of the genus Anguina and show nonmonophyly for the genera Mesoanguina and Heteroanguina. Morphological and biological characters are generally congruent with the anguinid groups identified in the rDNA phylogeny. Analyses of evolution of different gall types among anguinids reveal that there are apparent evolutionary trends in gall evolution: from abnormal swelling and growth of infested plant organs toward small localised galls, and from infestation of vegetative toward generative organs. Our study demonstrates that the main anguinid groups are generally associated with host plants belonging to the same or related systematic groups. The comparison of the ITS phylogenies of anguinids parasitising Poaceae and their host grasses shows a high level of cospeciation events.

Animals↗
PubMed2002

Grasses and gall midges: plant defense and insect adaptation.

The interactions of two economically important gall midge species, the rice gall midge and the Hessian fly, with their host plants, rice and wheat, respectively, are characterized by plant defense via R genes and insect adaptation via avr genes. The interaction of a third gall midge species, the orange wheat blossom midge, with wheat defense R genes has not yet exhibited insect adaptation. Because of the simple genetics underlying important aspects of these gall midge-grass interactions, a unique opportunity exists for integrating plant and insect molecular genetics with coevolutionary ecology. We present an overview of some genetic, physiological, behavioral, and ecological studies that will contribute to this integration and point to areas in need of study.

Adaptation, Physiological↗
PubMed2001

Evolution of the gall wasp-host plant association.

Gall wasps, or cynipids, form the second largest radiation of galling insects with more than 1300 described species. According to current views, the first cynipids were phytophagous and developed in herb stems of the Asteraceae without modifying plant growth or development. The first galls were supposedly multichambered stem swellings, and subsequent trends involved increase in gall complexity and reduction in the number of larval chambers. Gall wasps also have many of the features believed to be characteristic for phytophagous insects radiating in parallel with their host plants. We tested these hypotheses by mapping characters onto a recent estimate of higher cynipid relationships from a morphology-based analysis of exemplar taxa, controlling for phylogenetic uncertainty using bootstrapping. Characters were also mapped onto a metatree including all gall wasps, assembled from phylogenetic analyses as well as recent classifications. The results contradict many of the current hypotheses. The first cynipids with extant descendants were not Asteraceae stem feeders but induced distinct single-chambered galls in reproductive organs of herbaceous Papaveraceae, or possibly Lamiaceae. There has been a general trend toward more complex galls but the herb-stem feeders evolved from ancestors inducing distinct galls and their larval chambers are best understood as cryptic galls. Woody hosts have been colonized only three times, making the apparently irreversible transition from herbs to woody hosts one of the most conservative features of the gall wasp-host plant association. The evolution of host plant preferences is characterized by colonization of preexisting host-plant lineages rather than by parallel cladogenesis. Cynipids are mono- or oligophagous and host-plant choice is strongly phylogenetically conserved. Yet, the few major host shifts have involved remarkably distantly related plants. Many shifts have been onto plant species already exploited by other gall wasps, suggesting that interspecific parasitism among cynipids facilitates colonization of novel host plants.

Animals↗
PubMed2004

Occurrence and characterization of entomogen galls in plants from natural vegetation areas in Delfinópolis, MG, Brazil.

In the present work we aimed to register the occurrence of galls, inductors, inquilines, and parasitoids in plants of three natural vegetation areas in Delfinópolis, MG, Brazil. Results obtained showed 22 types of galls collected from leaf, vein leaf, petioles, stem, and inflorescence of nineteen species belonging to fifteen distinct families. Concerning gall morphology, the following were collected: globoid, conicle, discoidal, fusiform, shell-shape, indefinite, and one substituition of an ovary by an immature. As principal inducers were found insects of the families Cecidomyiidae (Diptera), Psyllidae, and Diaspididae (Sternorrhyncha/Hemiptera). As parasitoids the most common are of the Chalcidoidea superfamily (Hymenoptera) and, as occasional inquilines, Polyxenidae (Diplopoda) and Psocodea (Psocoptera). The results of this study contribute to existing of knowledge host-plant diversity and gall-associated insects in rocky fields, cerrado, and gallery forests.

Animals↗
PubMed1988

Role of indoleacetic acid-lysine synthetase in regulation of indoleacetic acid pool size and virulence of Pseudomonas syringae subsp. savastanoi.

The phytopathogen Pseudomonas syringae subsp. savastanoi incites the production of galls on olive and oleander plants. Gall formation is dependent upon the bacterial synthesis of the phytohormone indole-3-acetic acid (IAA). Strains isolated from oleander galls are capable of further metabolizing IAA to an amino acid conjugate, 3-indoleacetyl-epsilon-L-lysine (IAA-lysine); bacterial olive gall isolates lack this activity. In this study, the cloned gene for IAA-lysine synthetase (iaaL+) was introduced into strains isolated from olive and oleander galls to determine its effect on the regulation of IAA pool size and virulence. IAA-lysine was synthesized by isolates from olive galls when iaaL+ was introduced by conjugation, but the amount of IAA which accumulated in culture by the transconjugant was reduced by one-third. When the iaaL+ locus of an oleander gall isolate was inactivated by Tn5 mutagenesis, the resulting mutant did not convert IAA to IAA-lysine; however, it accumulated fivefold more IAA in culture than the wild type did. When inoculated into oleander plants, the iaaL mutant did not cause typical gall symptoms, nor did it replicate within host tissue similarly to the wild type.

Conjugation, Genetic↗
PubMed1986

Cloning of the gene for indoleacetic acid-lysine synthetase from Pseudomonas syringae subsp. savastanoi.

The phytopathogen Pseudomonas syringae subsp. savastanoi incites the production of galls on olive and oleander plants. Gall formation is dependent on bacterial production of the phytohormone indoleacetic acid (IAA). The genetic determinants for IAA synthesis are located on a plasmid (pIAA) and are organized in an operon in oleander strains of the bacterium. P. syringae subsp. savastanoi further converts IAA to an amino acid conjugate, 3-indole-acetyl-epsilon-L-lysine (IAA-lysine). The gene for IAA-lysine synthetase (iaaL) was found on the IAA plasmid by screening pIAA deletion mutants for the ability to convert IAA to IAA-lysine. The iaaL locus was then cloned in the vector pUC8 from a bank of P. syringae subsp. savastanoi EW2009 plasmid DNA to construct recombinant plasmid pLG87. The specific activity of IAA-lysine synthetase in Escherichia coli transformed with pLG87 was 47 times higher than that of the enzyme extract from P. syringae subsp. savastanoi. The direction of transcription of the iaaL gene was determined to be opposite to that of the IAA operon. The location of the iaaL gene on pIAA1 was mapped by Tn5 insertion mutagenesis to a 2.5-kilobase-pair fragment 2 kilobase pairs from the IAA operon.

Chromosome Mapping↗
PubMed2003

Enhanced invertase activities in the galls of Hormaphis hamamelidis.

Invertases are sucrose hydrolyzing enzymes often associated with plant tissues acting as physiological sinks, and plant galls are physiological sinks. We investigated several types of invertase and their potential benefits in galls of the aphid Hormaphis hamamelidis. Invertase activities in galls differed from those in leaves throughout the growing season. Vacuolar invertase activities (per g FW) were always greater in galls than leaves. In contrast, cell wall invertase activities per g FW started low in galls, but increased with time and were greater than those in leaves after 1 month. Gall growth was most closely related to vacuolar invertase activity, whereas leaf growth was correlated with both vacuolar and cell wall invertase activities. In separate correlational studies of aphid fecundity and invertase activities, cell wall invertase activity per gall accounted for 15-21% of the variation in offspring per gall. Gall dry weight explained more of the variation in offspring per gall (34.2%) than did gall volume (17.8%), a likely indication of the importance of sink strength over the life of the gall. Increased invertase activity probably underlies the enhanced sink strength commonly observed in galls. Hormaphis hamamelidis fundatrices appear to maximize reproductive output by eliciting multiple beneficial responses from their hosts. Initial gall growth correlated positively with high vacuolar invertase activity, while later in the season aphid fecundity correlated positively with cell wall invertase activity.

Animals↗
PubMed2000

Extreme resistance to desiccation in overwintering larvae of the gall fly Eurosta solidaginis (Diptera, tephritidae).

During winter, larvae of the goldenrod gall fly Eurosta solidaginis are exposed for extended periods to severe low ambient temperatures and low humidities within plant galls. The resistance of these larvae to desiccation at various temperatures and humidities, the transition (critical) temperature, and the effects of treatment with organic solvents on the larval rates of water loss and on changes in osmolality during desiccation were examined. The water loss rates of the flesh fly Sarcophaga crassipalpis under desiccating conditions were also measured. The water permeability of the cuticle of E. solidaginis larvae was very low (0.038 microgram h(-1 )cm(-2 )Pa(-1) at 20 C and 4% relative humidity) compared with that of larvae of other species. The value for E. solidaginis is equivalent to that of the very drought-resistant larvae of the tenebrionid beetle Tenebrio molitor (0.038 microgram h(-1)cm(-2)Pa(-1) at 30 C). In contrast, the permeability of larvae of the flesh fly Sarcophaga crassipalpis at 20 C and 4 % relative humidity was 0.331 microgram h(-1) cm(-2)Pa(-1). The thermal dependence of the cuticular permeability increased with temperature by approximately 0.0010 +microgram h(-1) cm(-2)Pa(-1) C(-1) in the interval between 4 and 40 C. At the transition temperature of 40 C, the thermal dependence of the permeability increased abruptly to 0.0400 microgram h(-1)cm(-2)Pa(-1) C(-1). Larvae treated with hexane and acetone remained remarkably resistant to water loss. However, treatment with chloroform:methanol increased the water loss rate approximately 25-fold. During desiccation at 4 C and 4% relative humidity for 21 days, E. solidaginis larvae showed a mass loss of 18.5+/-4.4 % (mean +/- s.e.m., N=6). Animals dried under the same conditions over the same period showed a haemolymph osmolality of 851+/-75 mosmol kg(-1) (N=4). Larvae freshly removed from the galls showed a haemolymph osmolality of 918+/-67 mosmol kg(-1)(N=3). A higher osmolality in the dried compared with the fresh larvae would have been expected. The present observation suggests that important ions in the haemolymph may have been excreted or rendered osmotically inactive during desiccation.

Animals↗
PubMed2006

Galls and gall makers in plants from the Pé-de-Gigante Cerrado Reserve, Santa Rita do Passa Quatro, SP, Brazil.

Thirty-six morphologically different types of galls were obtained in leaves, leaflets, veins, petioles, stems, tendrils and flower buds from twenty-five species of plants in the Pé-de-Gigante Reserve, municipality of Santa Rita do Passa Quatro, state of São Paulo, Brazil. The host plant species belong to the closely related families Anacardiaceae, Annonaceae, Asteraceae, Bignoniaceae, Caryocaraceae, Erythroxylaceae, Fabaceae, Malpighiaceae, Melastomataceae, Myrtaceae, Ochnaceae, Polygalaceae, Sapindaceae, Sapotaceae, and Smilacaceae. The most common gall makers included Cecidomyiidae (Diptera), Pteromalidae (Hymenoptera) and Diaspididae (Sternorrhyncha-Hemiptera). This is the first report of galls found in the following plant genera: Gochnatia (Asteraceae), Distictela (Bignoniaceae), Banisteriopsis (Malpighiaceae), Ouratea (Ochnaceae), and Bredemeyera (Polygalaceae). The results of this work contribute to the body of knowledge about the relationship among host plants, gall makers, and the gall morphology of Pé-de-Gigante Cerrado Reserve.

Animals↗
PubMed2002

The population biology of oak gall wasps (Hymenoptera: Cynipidae).

Oak gall wasps (Hymenoptera: Cynipidae, Cynipini) are characterized by possession of complex cyclically parthenogenetic life cycles and the ability to induce a wide diversity of highly complex species- and generation-specific galls on oaks and other Fagaceae. The galls support species-rich, closed communities of inquilines and parasitoids that have become a model system in community ecology. We review recent advances in the ecology of oak cynipids, with particular emphasis on life cycle characteristics and the dynamics of the interactions between host plants, gall wasps, and natural enemies. We assess the importance of gall traits in structuring oak cynipid communities and summarize the evidence for bottom-up and top-down effects across trophic levels. We identify major unanswered questions and suggest approaches for the future.

Adaptation, Physiological↗