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BMC Genomics Oct 2013Crown gall (CG) (Agrobacterium tumefaciens) and the root lesion nematodes (RLNs) (Pratylenchus vulnus) are major challenges faced by the California walnut industry,...
BACKGROUND
Crown gall (CG) (Agrobacterium tumefaciens) and the root lesion nematodes (RLNs) (Pratylenchus vulnus) are major challenges faced by the California walnut industry, reducing productivity and increasing the cost of establishing and maintaining orchards. Current nematode control strategies include nematicides, crop rotation, and tolerant cultivars, but these methods have limits. Developing genetic resistance through novel approaches like RNA interference (RNAi) can address these problems. RNAi-mediated silencing of CG disease in walnut (Juglans regia L.) has been achieved previously. We sought to place both CG and nematode resistance into a single walnut rootstock genotype using co-transformation to stack the resistance genes. A. tumefaciens, carrying self-complimentary iaaM and ipt transgenes, and Agrobacterium rhizogenes, carrying a self-complimentary Pv010 gene from P. vulnus, were used as co-transformation vectors. RolABC genes were introduced by the resident T-DNA in the A. rhizogenes Ri-plasmid used as a vector for plant transformation. Pv010 and Pv194 (transgenic control) genes were also transferred separately using A. tumefaciens. To test for resistance, transformed walnut roots were challenged with P. vulnus and microshoots were challenged with a virulent strain of A. tumefaciens.
RESULTS
Combining the two bacterial strains at a 1:1 rather than 1:3 ratio increased the co-transformation efficiency. Although complete immunity to nematode infection was not observed, transgenic lines yielded up to 79% fewer nematodes per root following in vitro co-culture than untransformed controls. Transgenic line 33-3-1 exhibited complete crown gall control and 32% fewer nematodes. The transgenic plants had thicker, longer roots than untransformed controls possibly due to insertion of rolABC genes. When the Pv010 gene was present in roots with or without rolABC genes there was partial or complete control of RLNs. Transformation using only one vector showed 100% control in some lines.
CONCLUSIONS
CG and nematode resistance gene stacking controlled CG and RLNs simultaneously in walnuts. Silencing genes encoding iaaM, ipt, and Pv010 decrease CG formation and RLNs populations in walnut. Beneficial plant genotype and phenotype changes are caused by co-transformation using A. tumefaciens and A. rhizogenes strains. Viable resistance against root lesion nematodes in walnut plants may be accomplished in the future using this gene stacking technology.
Topics: Agrobacterium tumefaciens; Animals; Biological Assay; Disease Resistance; Genotype; Juglans; Nematoda; Plant Diseases; Plant Roots; Plant Tumors; Plants, Genetically Modified; Seeds; Transgenes
PubMed: 24083348
DOI: 10.1186/1471-2164-14-668 -
Applied and Environmental Microbiology Aug 2019is a rhizosphere bacterium that can infect wound sites on plants. The bacterium transfers a segment of DNA (T-DNA) from the Ti plasmid to the plant host cell via a type...
is a rhizosphere bacterium that can infect wound sites on plants. The bacterium transfers a segment of DNA (T-DNA) from the Ti plasmid to the plant host cell via a type IV secretion system where the DNA becomes integrated into the host cell chromosomes. The expression of T-DNA in the plant results in tumor formation. Although the binding of the bacteria to plant surfaces has been studied previously, there is little work on possible interactions of the bacteria with the plant cell wall. Seven of the 48 genes encoding putative glycoside hydrolases (, , , , , , and ) in the genome of C58 were found to play a role in virulence on tomato and Two of these genes ( and ; and ) encode enzymes capable of digesting polygalacturonic acid and, thus, may play a role in the digestion of pectin. One gene (; ) encodes an arabinosylfuranosidase, which could remove arabinose from the ends of polysaccharide chains. Two genes ( and ; and ) encode proteins with β-glycosidase activity and could digest a variety of plant cell wall oligosaccharides and polysaccharides. One gene (; ) encodes a putative xylanase, which may play a role in the digestion of xylan. Another gene (; ) encodes a protein with α-galactosidase activity and may be involved in the breakdown of arabinogalactans. Limited digestion of the plant cell wall by may be involved in tumor formation on tomato and is used in the construction of genetically engineered plants, as it is able to transfer DNA to plant hosts. Knowledge of the mechanisms of DNA transfer and the genes required will aid in the understanding of this process. Manipulation of glycoside hydrolases may increase transformation and widen the host range of the bacterium. also causes disease (crown gall tumors) on a variety of plants, including stone fruit trees, grapes, and grafted ornamentals such as roses. It is possible that compounds that inhibit glycoside hydrolases could be used to control crown gall disease caused by .
Topics: Agrobacterium tumefaciens; Bacterial Proteins; Crassulaceae; Genes, Bacterial; Glycoside Hydrolases; Solanum lycopersicum; Plant Diseases; Plant Tumors; Virulence
PubMed: 31126942
DOI: 10.1128/AEM.00603-19 -
BMC Ecology and Evolution Jun 2021Interspecific interactions among insect herbivores are common and important. Because they are surrounded by plant tissue (endophagy), the interactions between...
BACKGROUND
Interspecific interactions among insect herbivores are common and important. Because they are surrounded by plant tissue (endophagy), the interactions between gall-formers and other herbivores are primarily plant-mediated. Gall-forming insects manipulate their host to gain a better nutrient supply, as well as physical and chemical protection form natural enemies and abiotic factors. Although often recognized, the protective role of the galls has rarely been tested.
RESULTS
Using an experimental approach, we found that the aphid, Smynthurodes betae, that forms galls on Pistacia atlantica leaves, is fully protected from destruction by the folivorous processionary moth, Thaumetopoea solitaria. The moth can skeletonize entire leaves on the tree except for a narrow margin around the galls that remains intact ("trimmed galls"). The fitness of the aphids in trimmed galls is unharmed. Feeding trials revealed that the galls are unpalatable to the moth and reduce its growth. Surprisingly, S. betae benefits from the moth. The compensatory secondary leaf flush following moth defoliation provides new, young leaves suitable for further gall induction that increase overall gall density and reproduction of the aphid.
CONCLUSIONS
We provide experimental support for the gall defense hypothesis. The aphids in the galls are protracted by plant-mediated mechanisms that shape the interactions between insect herbivores which feed simultaneously on the same host. The moth increase gall demsity on re-growing defoliated shoots.
Topics: Animals; Aphids; Herbivory; Larva; Pistacia; Plant Tumors
PubMed: 34144674
DOI: 10.1186/s12862-021-01861-2 -
Scientific Reports Nov 2019Agrobacterium-mediated plant galls are often misdiagnosed as nematode-mediated knots, even by experts, because the gall symptoms in both conditions are very similar. In...
Agrobacterium-mediated plant galls are often misdiagnosed as nematode-mediated knots, even by experts, because the gall symptoms in both conditions are very similar. In the present study, we developed biosensor strains based on agrobacterial opine metabolism that easily and simply diagnoses Agrobacterium-induced root galls. Our biosensor consists of Agrobacterium mannitol (ABM) agar medium, X-gal, and a biosensor. The working principle of the biosensor is that exogenous nopaline produced by plant root galls binds to NocR, resulting in NocR/nopaline complexes that bind to the promoter of the nopaline oxidase gene (nox) operon and activate the transcription of noxB-lacZY, resulting in readily visualized blue pigmentation on ABM agar medium supplemented with X-gal (ABMX-gal). Similarly, exogenous octopine binds to OccR, resulting in OoxR/octopine complexes that bind to the promoter of the octopine oxidase gene (oox) operon and activate the transcription of ooxB-lacZY, resulting in blue pigmentation in the presence of X-gal. Our biosensor is successfully senses opines produced by Agrobacterium-infected plant galls, and can be applied to easily distinguish Agrobacterium crown gall disease from nematode disease.
Topics: Agrobacterium tumefaciens; Animals; Biosensing Techniques; Nematoda; Plant Tumors; Plants
PubMed: 31784634
DOI: 10.1038/s41598-019-54568-2 -
Applied and Environmental Microbiology May 2019Crown gall disease caused by severely impacts the production of peach and other fruit trees. Several peach cultivars are partially resistant to , but little is known...
Crown gall disease caused by severely impacts the production of peach and other fruit trees. Several peach cultivars are partially resistant to , but little is known about the roles of endophytic microbiota in disease resistance. In the present study, the endophytic bacterial communities of resistant and susceptible peach cultivars "Honggengansutao" and "Okinawa" were analyzed using universal 16S rRNA gene amplicon sequencing in parallel with the cultivation and characterization of bacterial isolates. A total of 1,357,088 high-quality sequences representing 3,160 distinct operational taxonomic units (OTUs; , , , and ) and 1,200 isolates of 20 genera and 305 distinct ribotypes were collected from peach roots and twigs. It was found that factors including plant developmental stage, cultivar, and invasion strongly influenced the peach endophytic communities. The community diversity of endophytic bacteria and the abundance of culturable bacteria were both higher in the roots of the resistant cultivar, particularly after inoculation. Strikingly, the pathogen antagonists and in roots and in twigs were most frequently detected in resistant plants. Our results suggest that the higher abundance and diversity of endophytic bacteria and increased proportions of antagonistic bacteria might contribute to the natural defense of the resistant cultivar against This work reveals the relationships between endophytic bacteria and disease resistance in peach plants and provides important information for microbiome-based biocontrol of crown gall disease in fruit trees. as the causal agent of peach crown gall disease can be controlled by planting resistant cultivars. This study profiles the endophytic bacteria in susceptible and resistant peach cultivars, advancing our understanding of the relationships between endophytic bacterial communities and peach crown gall disease, with potential implications for other complex microbiome-plant-pathogen interactions. The resistant cultivar may defend itself by increasing the diversity and abundance of beneficial endophytic bacteria. The antagonists identified among the genera , , and may have application potential for biocontrol of crown gall disease in fruit trees.
Topics: Agrobacterium tumefaciens; Bacterial Physiological Phenomena; Disease Resistance; Endophytes; Microbiota; Plant Tumors; Prunus persica; RNA, Bacterial; RNA, Ribosomal, 16S; Species Specificity
PubMed: 30824451
DOI: 10.1128/AEM.02931-18 -
In vitro antibacterial and antitumor activities of some medicinal plant extracts, growing in Turkey.Asian Pacific Journal of Tropical... Aug 2013To investigate antibacterial and antitumor activities of 51 different extracts prepared with 3 types of solvents (water, ethanol and methanol) of 16 different plant...
OBJECTIVE
To investigate antibacterial and antitumor activities of 51 different extracts prepared with 3 types of solvents (water, ethanol and methanol) of 16 different plant species (Ajuga reptans (A. reptans) L., Phlomis pungens (P. pungens) Willd., Marrubium astracanicum (M. astracanicum) Jacq., Nepeta nuda (N. nuda) L., Stachys annua (S. annua) L., Genista lydia (G. lydia) Boiss., Nuphar lutea (N. lutea) L., Nymphaea alba (N. alba) L., Vinca minor (V. minor) L., Stellaria media (S. media) L., Capsella bursa-pastoris (C. bursa-pastoris) L., Galium spurium (G. spurium) L., Onosma heterophyllum (O. heterophyllum) Griseb., Reseda luteola (R. luteola) L., Viburnum lantana (V. lantana) L. and Mercurialis annua (M. annua) L.) grown in Turkey was conducted.
METHODS
Antibacterial activity was evaluated with 10 bacteria including Streptococcus pyogenes (S. pyogenes), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), Escheria coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella typhimurium (S. typhimurium), Serratia marcescens (S. marcescens), Proteus vulgaris (P. vulgaris), Enterobacter cloacae (E. cloacea), and Klebsiella pneumoniae (K. pneumoniae) by using disc diffusion method. Antitumor activity was evaluated with Agrobacterium tumefaciens (A. tumefaciens)-induced potato disc tumor assay.
RESULTS
Best antibacterial activity was obtained with ethanolic extract of P. pungens against S. pyogenes. Ethanolic and methanolic extract of N. alba and ethanolic extract of G. lydia also showed strong antibacterial activities. Results indicated that alcoholic extracts especially ethanolic extracts exhibited strong antibacterial activity against both gram-positive and gram-negative bacteria. Best antitumor activity was obtained with methanolic extracts of N. alba and V. lantana (100% tumor inhibition). Ethanolic extract of N. alba, alcoholic extracts of N. lutea, A. reptans and V. minor flowers, methanolic extracts of G. lydia and O. heterophyllum and ethanolic extract of V. lantana and aqueous extract of V. minor leaves exhibited strong tumor inhibitions.
CONCLUSIONS
In near future works, identification of active components can be studied for plant extracts having strong bioactivity.
Topics: Anti-Bacterial Agents; Antineoplastic Agents; Bacteria; Humans; Plant Extracts; Plant Tumors; Plants, Medicinal; Turkey
PubMed: 23790332
DOI: 10.1016/S1995-7645(13)60106-6 -
Anais Da Academia Brasileira de Ciencias 2021This 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...
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.
Topics: Animals; Brazil; Fabaceae; Host-Parasite Interactions; Humans; Insecta; Plant Tumors
PubMed: 34586179
DOI: 10.1590/0001-3765202120201442 -
PloS One 2012Dioecy represents a source of variation in plant quality to herbivores due to sexual differences in intensity and timing of resource allocation to growth, defense and...
BACKGROUND
Dioecy represents a source of variation in plant quality to herbivores due to sexual differences in intensity and timing of resource allocation to growth, defense and reproduction. Male plants have higher growth rates and should be more susceptible to herbivores than females, due to a lower investment in defense and reproduction.
METHODOLOGY/PRINCIPAL FINDINGS
We compared resource investment to growth and reproduction and its consequences to herbivore attack on three Baccharis species along one year (B. dracunculifolia, B. ramosissima, and B. concinna). Phenological patterns presented by the three species of Baccharis were quite different over time, but the number of fourth-level shoots and plant growth rate did not differ between sexes in any studied species. Intersexual difference in reproductive investment was only observed for B. concinna, with female individuals supporting higher inflorescence density than male individuals throughout the year. Gall abundance on the three Baccharis species was not influenced by plant sex. However, all plant traits evaluated here positively influenced the gall abundance on B. concinna, whereas only the number of fourth-level shoots positively influenced gall abundance on B. ramosissima and B. dracunculifolia.
CONCLUSIONS/SIGNIFICANCE
The absence of differential reproductive allocation may have contributed to similar growth and shoot production between the sexes, with bottom-up effects resulting in gender similarities in gall abundance patterns. The number of fourth-level shoots, an indicator of meristem availability to herbivores, was the most important driver of the abundance of the galling insects regardless of host plant gender or species. Albeit the absence of intersexual variation in insect gall abundance is uncommon in the literature, the detailed study of the exceptions may bring more light to understand the mechanisms and processes behind such trend.
Topics: Animals; Baccharis; Ecological and Environmental Phenomena; Herbivory; Plant Tumors; Reproduction; Sex Characteristics; Time Factors
PubMed: 23056517
DOI: 10.1371/journal.pone.0046896 -
Plant Physiology and Biochemistry : PPB Feb 2019Trehalose and its precursor, trehalose 6-phosphate (T6P), are essential regulators of plant response to abiotic and biotic stress. Here we used the specific host-insect...
Trehalose and its precursor, trehalose 6-phosphate (T6P), are essential regulators of plant response to abiotic and biotic stress. Here we used the specific host-insect interaction between Linaria vulgaris (Plantaginaceae) and stem-galling weevil, Rhinusa pilosa (Mecinini, Curculionidae) with the aim to distinguish carbohydrate allocation patterns in response to herbivory, gall formation (G1, 24 h after oviposition), and gall development (G2, 7 days after oviposition) under controlled conditions. The hypothesis is that herbivory and galling induce distinct responses in both leaves and stems, and that shifts in carbon allocations are regulated by signaling sugars. Systemic response to herbivory was accumulation of T6P and maltose. The main feature of G1 in the stems was accumulation of trehalose, accompanied by increased T6P, turanose and glucose content, oppositely to the leaves. In G2, galls had 3-folds higher weight than controls, with further accumulation of fructose, glucose, turanose, and total water-insoluble carbohydrates (TIC), while the sucrose/hexose ratio decreased. Analysis of fast chlorophyll fluorescence kinetic (OJIP) transients in G2 showed a slight decrease in quantum yield of electron transport flux from Q to Q, and towards photosystem I acceptor side, correlated with the decreased content of photosynthetic pigments and hexoses accumulation. Redistribution of photosynthates, and accumulation of T6P were induced in response to herbivory, indicating its signaling role. The results support the hypothesis that R. pilosa can induce plant reprogramming towards the accumulation of beneficial carbohydrates in developing gall by mechanisms which include both T6P and trehalose.
Topics: Animals; Chlorophyll; Fructose; Glucose; Herbivory; Linaria; Plant Leaves; Plant Stems; Plant Tumors; Trehalose; Weevils
PubMed: 30578998
DOI: 10.1016/j.plaphy.2018.11.032 -
Molecules (Basel, Switzerland) Jan 2022FT-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...
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 ring vibration and the subsequent intensification of the 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.
Topics: Plant Tumors; Polyphenols; Quercus; Spectrum Analysis, Raman
PubMed: 35011511
DOI: 10.3390/molecules27010279