262 research outputs found
A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita
© The Author(s). 2018Background: Southern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment. Results: A total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle. Conclusions: Here we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.Peer reviewedFinal Published versio
Nanostructured Systems Containing Rutin: In Vitro Antioxidant Activity and Photostability Studies
The improvement of the rutin photostability and its prolonged in vitro antioxidant activity were studied by means of its association with nanostructured aqueous dispersions. Rutin-loaded nanocapsules and rutin-loaded nanoemulsion showed mean particle size of 124.30 ± 2.06 and 124.17 ± 1.79, respectively, polydispersity index below 0.20, negative zeta potential, and encapsulation efficiency close to 100%. The in vitro antioxidant activity was evaluated by the formation of free radical ·OH after the exposure of hydrogen peroxide to a UV irradiation system. Rutin-loaded nanostructures showed lower rutin decay rates [(6.1 ± 0.6) 10−3 and (5.1 ± 0.4) 10−3 for nanocapsules and nanoemulsion, respectively] compared to the ethanolic solution [(35.0 ± 3.7) 10−3 min−1] and exposed solution [(40.1 ± 1.7) 10−3 min−1] as well as compared to exposed nanostructured dispersions [(19.5 ± 0.5) 10−3 and (26.6 ± 2.6) 10−3, for nanocapsules and nanoemulsion, respectively]. The presence of the polymeric layer in nanocapsules was fundamental to obtain a prolonged antioxidant activity, even if the mathematical modeling of the in vitro release profiles showed high adsorption of rutin to the particle/droplet surface for both formulations. Rutin-loaded nanostructures represent alternatives to the development of innovative nanomedicines
Novel simple sequence repeats (SSRs) detected by ND-FISH in heterochromatin of Drosophila melanogaster
<p>Abstract</p> <p>Background</p> <p>In recent years, substantial progress has been made in understanding the organization of sequences in heterochromatin regions containing single-copy genes and transposable elements. However, the sequence and organization of tandem repeat DNA sequences, which are by far the majority fraction of <it>D. melanogaster </it>heterochromatin, are little understood.</p> <p>Results</p> <p>This paper reports that the heterochromatin, as well as containing long tandem arrays of pentanucleotide satellites (AAGAG, AAGAC, AATAT, AATAC and AACAC), is also enriched in other simple sequence repeats (SSRs) such as A, AC, AG, AAG, ACT, GATA and GACA. Non-denaturing FISH (ND-FISH) showed these SSRs to localize to the chromocentre of polytene chromosomes, and was used to map them on mitotic chromosomes. Different distributions were detected ranging from single heterochromatic clusters to complex combinations on different chromosomes. ND-FISH performed on extended DNA fibres, along with Southern blotting, showed the complex organization of these heterochromatin sequences in long tracts, and revealed subclusters of SSRs (several kilobase in length) flanked by other DNA sequences. The chromosomal characterization of C, AAC, AGG, AAT, CCG, ACG, AGC, ATC and ACC provided further detailed information on the SSR content of <it>D. melanogaster </it>at the whole genome level.</p> <p>Conclusion</p> <p>These data clearly show the variation in the abundance of different SSR motifs and reveal their non-random distribution within and between chromosomes. The greater representation of certain SSRs in <it>D. melanogaster </it>heterochromatin suggests that its complexity may be greater than previously thought.</p
Biosynthesis of Unusual Moth Pheromone Components Involves Two Different Pathways in the Navel Orangeworm, Amyelois transitella
The sex pheromone of the navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), consists of two different types of components, one type including (11Z,13Z)-11,13-hexadecadienal (11Z,13Z-16:Ald) with a terminal functional group containing oxygen, similar to the majority of moth pheromones reported, and another type including the unusual long-chain pentaenes, (3Z,6Z,9Z,12Z,15Z)-3,6,9,12,15-tricosapentaene (3Z,6Z,9Z,12Z,15Z-23:H) and (3Z,6Z,9Z,12Z,15Z)- 3,6,9,12,15-pentacosapentaene (3Z,6Z,9Z,12Z,15Z-25:H). After decapitation of females, the titer of 11Z,13Z-16:Ald in the pheromone gland decreased significantly, whereas the titer of the pentaenes remained unchanged. Injection of a pheromone biosynthesis activating peptide (PBAN) into the abdomens of decapitated females restored the titer of 11Z,13Z-16:Ald and even increased it above that in intact females, whereas the titer of the pentaenes in the pheromone gland was not affected by PBAN injection. In addition to common fatty acids, two likely precursors of 11Z,13Z-16:Ald, i.e., (Z)-11-hexadecenoic and (11Z,13Z)-11,13-hexadecadienoic acid, as well as traces of (Z)-6-hexadecenoic acid, were found in gland extracts. In addition, pheromone gland lipids contained (5Z,8Z,11Z,14Z,17Z)-5,8,11,14,17-icosapentaenoic acid, which also was found in extracts of the rest of the abdomen. Deuterium-labeled fatty acids, (16,16,16-D3)-hexadecanoic acid and (Z)-[13,13,14,14,15,15,16,16,16-D9]-11-hexadecenoic acid, were incorporated into 11Z,13Z-16:Ald after topical application to the sex pheromone gland coupled with abdominal injection of PBAN. Deuterium label was incorporated into the C23 and C25 pentaenes after injection of (9Z,12Z,15Z)- [17,17,18,18,18-D5]-9,12,15-octadecatrienoic acid into 1–2 d old female pupae. These labeling results, in conjunction with the composition of fatty acid intermediates found in pheromone gland extracts, support different pathways leading to the two pheromone components. 11Z,13Z-16:Ald is probably produced in the pheromone gland by Δ11 desaturation of palmitic acid to 11Z-16:Acid followed by a second desaturation to form 11Z,13Z-16:Acid and subsequent reduction and oxidation. The production of 3Z,6Z,9Z,12Z,15Z-23:H and 3Z,6Z,9Z,12Z,15Z-25:H may take place outside the pheromone gland, and appears to start from linolenic acid, which is elongated and desaturated to form (5Z,8Z,11Z,14Z,17Z)-5,8,11,14,17-icosapentaenoic acid, followed by two or three further elongation steps and finally reductive decarboxylation
Strain-induced pseudomagnetic field and Landau levels in photonic structures
Magnetic effects at optical frequencies are notoriously weak. This is
evidenced by the fact that the magnetic permeability of nearly all materials is
unity in the optical frequency range, and that magneto-optical devices (such as
Faraday isolators) must be large in order to allow for a sufficiently strong
effect. In graphene, however, it has been shown that inhomogeneous strains can
induce 'pseudomagnetic fields' that behave very similarly to real fields. Here,
we show experimentally and theoretically that, by properly structuring a
dielectric lattice, it is possible to induce a pseudomagnetic field at optical
frequencies in a photonic lattice, where the propagation dynamics is equivalent
to the evolution of an electronic wavepacket in graphene. To our knowledge,
this is the first realization of a pseudomagnetic field in optics. The induced
field gives rise to multiple photonic Landau levels (singularities in the
density of states) separated by band gaps. We show experimentally and
numerically that the gaps between these Landau levels give rise to transverse
confinement of the optical modes. The use of strain allows for the exploration
of magnetic effects in a non-resonant way that would be otherwise inaccessible
in optics. Employing inhomogeneous strain to induce pseudomagnetism suggests
the possibility that aperiodic photonic crystal structures can achieve greater
field-enhancement and slow-light effects than periodic structures via the high
density-of-states at Landau levels. Generalizing these concepts to other
systems beyond optics, for example with matter waves in optical potentials,
offers new intriguing physics that is fundamentally different from that in
purely periodic structures.Comment: 24 pages including supplementary information section, 4 figure
Mycobacterial dihydrofolate reductase inhibitors identified using chemogenomic methods and in vitro validation.
The lack of success in target-based screening approaches to the discovery of antibacterial agents has led to reemergence of phenotypic screening as a successful approach of identifying bioactive, antibacterial compounds. A challenge though with this route is then to identify the molecular target(s) and mechanism of action of the hits. This target identification, or deorphanization step, is often essential in further optimization and validation studies. Direct experimental identification of the molecular target of a screening hit is often complex, precisely because the properties and specificity of the hit are not yet optimized against that target, and so many false positives are often obtained. An alternative is to use computational, predictive, approaches to hypothesize a mechanism of action, which can then be validated in a more directed and efficient manner. Specifically here we present experimental validation of an in silico prediction from a large-scale screen performed against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. The two potent anti-tubercular compounds studied in this case, belonging to the tetrahydro-1,3,5-triazin-2-amine (THT) family, were predicted and confirmed to be an inhibitor of dihydrofolate reductase (DHFR), a known essential Mtb gene, and already clinically validated as a drug target. Given the large number of similar screening data sets shared amongst the community, this in vitro validation of these target predictions gives weight to computational approaches to establish the mechanism of action (MoA) of novel screening hit
Cis-by-Trans Regulatory Divergence Causes the Asymmetric Lethal Effects of an Ancestral Hybrid Incompatibility Gene
The Dobzhansky and Muller (D-M) model explains the evolution of hybrid incompatibility (HI) through the interaction between lineage-specific derived alleles at two or more loci. In agreement with the expectation that HI results from functional divergence, many protein-coding genes that contribute to incompatibilities between species show signatures of adaptive evolution, including Lhr, which encodes a heterochromatin protein whose amino acid sequence has diverged extensively between Drosophila melanogaster and D. simulans by natural selection. The lethality of D. melanogaster/D. simulans F1 hybrid sons is rescued by removing D. simulans Lhr, but not D. melanogaster Lhr, suggesting that the lethal effect results from adaptive evolution in the D. simulans lineage. It has been proposed that adaptive protein divergence in Lhr reflects antagonistic coevolution with species-specific heterochromatin sequences and that defects in LHR protein localization cause hybrid lethality. Here we present surprising results that are inconsistent with this coding-sequence-based model. Using Lhr transgenes expressed under native conditions, we find no evidence that LHR localization differs between D. melanogaster and D. simulans, nor do we find evidence that it mislocalizes in their interspecific hybrids. Rather, we demonstrate that Lhr orthologs are differentially expressed in the hybrid background, with the levels of D. simulans Lhr double that of D. melanogaster Lhr. We further show that this asymmetric expression is caused by cis-by-trans regulatory divergence of Lhr. Therefore, the non-equivalent hybrid lethal effects of Lhr orthologs can be explained by asymmetric expression of a molecular function that is shared by both orthologs and thus was presumably inherited from the ancestral allele of Lhr. We present a model whereby hybrid lethality occurs by the interaction between evolutionarily ancestral and derived alleles
Characterization of callase (β-1,3-d-glucanase) activity during microsporogenesis in the sterile anthers of Allium sativum L. and the fertile anthers of A. atropurpureum
We examined callase activity in anthers of sterile Allium sativum (garlic) and fertile Allium atropurpureum. In A. sativum, a species that produces sterile pollen and propagates only vegetatively, callase was extracted from the thick walls of A. sativum microspore tetrads exhibited maximum activity at pH 4.8, and the corresponding in vivo values ranged from 4.5 to 5.0. Once microspores were released, in vitro callase activity peaked at three distinct pH values, reflecting the presence of three callase isoforms. One isoform, which was previously identified in the tetrad stage, displayed maximum activity at pH 4.8, and the remaining two isoforms, which were novel, were most active at pH 6.0 and 7.3. The corresponding in vivo values ranged from pH 4.75 to 6.0. In contrast, in A. atropurpureum, a sexually propagating species, three callase isoforms, active at pH 4.8–5.2, 6.1, and 7.3, were identified in samples of microsporangia that had released their microspores. The corresponding in vivo value for this plant was 5.9. The callose wall persists around A. sativum meiotic cells, whereas only one callase isoform, with an optimum activity of pH 4.8, is active in the acidic environment of the microsporangium. However, this isoform is degraded when the pH rises to 6.0 and two other callase isoforms, maximally active at pH 6.0 and 7.3, appear. Thus, factors that alter the pH of the microsporangium may indirectly affect the male gametophyte development by modulating the activity of callase and thereby regulating the degradation of the callose wall
Response of Quercus ilex seedlings to Phytophthora spp. root infection in a soil infestation test
[EN] Phytophthora species are the main agents associated with oak (Quercus spp.) decline, together with the changing environmental conditions and the intensive land use. The aim of this study was to evaluate the susceptibility of Quercus ilex to the inoculation with eight Phytophthora species. Seven to eight month old Q. ilex seedlings grown from acorns,
obtained from two Spanish origins, were inoculated with P. cinnamomi, P. cryptogea, P. gonapodyides, P. megasperma, P. nicotianae, P. plurivora, P. psychrophila and P. quercina. All Phytophthora inoculated seedlings showed decline and symptoms including small dark necrotic root lesions, root cankers, and loss of fine roots and tap root. The most aggressive species were P. cinnamomi, P. cryptogea, P. gonapodyides, P. plurivora and P. psychrophila followed by P. megasperma., while Phytophthora quercina and P. nicotianae were the less aggressive species. Results obtained confirm that these Phytophthora species could constituted a threat to Q. ilex ecosystems and the implications are further discussed.The authors are grateful to A. Solla and his team from the Centro Universitario de Plasencia-Universidad de Extremadura (Spain) for helping in the acorns collection and to the CIEF (Centro para la Investigación y Experimentación Forestal, Generalitat Valenciana, Valencia, Spain) for providing the acorns. This research was supported by funding from the project AGL2011- 30438-C02-01 (Ministerio de Economía y Competitividad, Spain).Mora-Sala, B.; Abad Campos, P.; Berbegal Martinez, M. (2018). Response of Quercus ilex seedlings to Phytophthora spp. root infection in a soil infestation test. European Journal of Plant Pathology. https://doi.org/10.1007/s10658-018-01650-6SÁlvarez, L. A., Pérez-Sierra, A., Armengol, J., & García-Jiménez, J. (2007). Characterization of Phytophthora nicotianae isolates causing collar and root rot of lavender and rosemary in Spain. Journal of Plant Pathology, 89, 261–264.Balci, Y., & Halmschlager, E. (2003a). Incidence of Phytophthora species in oak forests in Austria and their possible involvement in oak decline. Forest Pathology, 33, 157–174.Balci, Y., & Halmschlager, E. (2003b). Phytophthora species in oak ecosystems in Turkey and their association with declining oak trees. Plant Pathology, 52, 694–702.Brasier, C. M. (1992a). Oak tree mortality in Iberia. Nature, 360, 539.Brasier, C. M. ((1992b)). Phytophthora cinnamomi as a contributory factor on European oak declines. In N. by Luisi, P. Lerario, & A. B. Vannini (Eds.), Recent Advances in Studies on Oak Decline. Proc. Int. Congress, Brindisi, Italy, September 13-18, 1992 (pp. 49–58). Italy: Università degli Studi.Brasier, C. M. (1996). Phytophthora cinnamomi and oak decline in southern Europe. Environmental constraints including climate change. Annales des Sciences Forestieres, 53, 347–358.Brasier, C. M. (2008). The biosecurity threat to the UK and global environment from international trade in plants. Plant Pathology, 57, 792–808.Brasier, C. M., Hamm, P. B., & Hansen, E. M. (1993a). Cultural characters, protein patterns and unusual mating behaviour of P. gonapodyides isolates from Britain and North America. Mycological Research, 97, 1287–1298.Brasier, C. M., Robredo, F., & Ferraz, J. F. P. (1993b). Evidence for Phytophthora cinnamomi involvement in Iberian oak decline. Plant Pathology, 42, 140–145.Camilo-Alves, C. S. P., Clara, M. I. E., & Ribeiro, N. M. C. A. (2013). Decline of Mediterranean oak trees and its association with Phytophthora cinnamomi: a review. European Journal of Forest Research, 132, 411–432.Català, S., Berbegal, M., Pérez-Sierra, A., & Abad-Campos, P. (2017). Metabarcoding and development of new real-time specific assays reveal Phytophthora species diversity in holm oak forests in eastern Spain. Plant Pathology, 66, 115–123.Collett, D. (2003). Modelling survival data in medical research (2nd ed.). Boca Raton: Chapman & Hall/CRC, 410 pp.Corcobado, T., Cubera, E., Pérez-Sierra, A., Jung, T., & Solla, A. (2010). First report of Phytophthora gonapodyides involved in the decline of Quercus ilex in xeric conditions in Spain. New Disease Reports, 22, 33.Corcobado, T., Cubera, E., Moreno, G., & Solla, A. (2013). Quercus ilex forests are influenced by annual variations in water table, soil water deficit and fine root loss caused by Phytophthora cinnamomi. Agricultural and Forest Meteorology, 169, 92–99.Corcobado, T., Vivas, M., Moreno, G., & Solla, A. (2014). Ectomycorrhizal symbiosis in declining and non-declining Quercus ilex trees infected with or free of Phytophthora cinnamomi. Forest Ecology and Management, 324, 72–80.Corcobado, T., Miranda-Torres, J. J., Martín-García, J., Jung, T., & Solla, A. (2017). Early survival of Quercus ilex subspecies from different populations after infections and co-infections by multiple Phytophthora species. Plant Pathology, 66, 792–804.Erwin, D. C., & Ribeiro, O. K. (1996). Phytophthora diseases worldwide. St. Paul, Minnesota,USA: APS Press, American Phytopathological. Society 562pp.Gallego, F. J., Perez de Algaba, A., & Fernandez-Escobar, R. (1999). Etiology of oak decline in Spain. European Journal of Forest Pathology, 29, 17–27.Hansen, E., & Delatour, C. (1999). Phytophthora species in oak forests of north-east France. Annals of Forest Science, 56, 539–547.Hardham, A. R., & Blackman, L. M. (2010). Molecular cytology of Phytophthora plant interactions. Australasian Plant Pathology, 39, 29.Hernández-Lambraño, R. E., González-Moreno, P., & Sánchez-Agudo, J. Á. (2018). Environmental factors associated with the spatial distribution of invasive plant pathogens in the Iberian Peninsula: The case of Phytophthora cinnamomi Rands. Forest Ecology and Management, 419, 101–109.Jankowiak, R., Stępniewska, H., Bilański, P., & Kolařík, M. (2014). Occurrence of Phytophthora plurivora and other Phytophthora species in oak forests of southern Poland and their association with site conditions and the health status of trees. Folia Microbiologica, 59, 531–542.Jeffers, S. N., & Aldwinckle, H. S. (1987). Enhancing detection of Phytophthora cactorum in naturally infested soil. Phytopathology, 77, 1475–1482.Jiménez, A. J., Sánchez, E. J., Romero, M. A., Belbahri, L., Trapero, A., Lefort, F., & Sánchez, M. E. (2008). Pathogenicity of Pythium spiculum and P. sterilum on feeder roots of Quercus rotundifolia. Plant Pathology, 57, 369.Jönsson, U. (2006). A conceptual model for the development of Phytophthora disease in Quercus robur. New Phytologist, 171, 55–68.Jönsson, U., Jung, T., Rosengren, U., Nihlgard, B., & Sonesson, K. (2003). Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils. New Phytologist, 158, 355–364.Jung, T., & Burgess, T. I. (2009). Re-evaluation of Phytophthora citricola isolates from multiple woody hosts in Europe and North America reveals a new species, Phytophthora plurivora sp. nov. Persoonia, 22, 95–110.Jung, T., Blaschke, H., & Neumann, P. (1996). Isolation, identification and pathogenicity of Phytophthora species from declining oak stands. European Journal of Forest Pathology, 26, 253–272.Jung, T., Cooke, D. E. L., Blaschke, H., Duncan, J. M., & Oßwald, W. (1999). Phytophthora quercina sp. nov., causing root rot of European oaks. Mycological Research, 103, 785–798.Jung, T., Blaschke, H., & Oßwald, W. (2000). Involvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease. Plant Pathology, 49, 706–718.Jung, T., Hansen, E. M., Winton, L., Oßwald, W., & Delatour, C. (2002). Three new species of Phytophthora from European oak forests. Mycological Research, 106, 397–411.Jung, T., Orlikowski, L., Henricot, B., Abad-Campos, P., Aday, A. G., Aguín Casal, O., Bakonyi, J., Cacciola, S. O., Cech, T., Chavarriaga, D., Corcobado, T., Cravador, A., Decourcelle, T., Denton, G., Diamandis, S., Dogmus-Lehtijärvi, H. T., Franceschini, A., Ginetti, B., Glavendekic, M., Hantula, J., Hartmann, G., Herrero, M., Ivic, D., Horta Jung, M., Lilja, A., Keca, N., Kramarets, V., Lyubenova, A., Machado, H., Magnano di San Lio, G., Mansilla Vázquez, P. J., Marçais, B., Matsiakh, I., Milenkovic, I., Moricca, S., Nagy, Z. Á., Nechwatal, J., Olsson, C., Oszako, T., Pane, A., Paplomatas, E. J., Pintos Varela, C., Prospero, S., Rial Martínez, C., Rigling, D., Robin, C., Rytkönen, A., Sánchez, M. E., Scanu, B., Schlenzig, A., Schumacher, J., Slavov, S., Solla, A., Sousa, E., Stenlid, J., Talgø, V., Tomic, Z., Tsopelas, P., Vannini, A., Vettraino, A. M., Wenneker, M., Woodward, S., & Peréz-Sierra, A. (2016). Widespread Phytophthora infestations in European nurseries put forest, semi-natural and horticultural ecosystems at high risk of Phytophthora diseases. Forest Pathology, 46, 134–163.Kroon, L. P., Brouwer, H., de Cock, A. W., & Govers, F. (2012). The genus Phytophthora anno 2012. Phytopathology, 102, 348–364.Linaldeddu, B. T., Scanu, B., Maddau, L., & Franceschini, A. (2014). Diplodia corticola and Phytophthora cinnamomi: the main pathogens involved in holm oak decline on Caprera Island (Italy). Forest Pathology, 44, 191–200.Luque, J., Parladé, J., & Pera, J. (2000). Pathogenicity of fungi isolated from Quercus suber in Catalonia (NE Spain). Forest Pathology, 30, 247–263.Luque, J., Parladé, J., & Pera, J. (2002). Seasonal changes in susceptibility of Quercus suber to Botryosphaeria stevensii and Phytophthora cinnamomi. Plant Pathology, 51, 338–345.MAGRAMA. (2014). Diagnóstico del Sector Forestal Español. Análisis y Prospectiva - Serie Agrinfo/Medioambiente n° 8. Ed. Ministerio de Agricultura, Alimentación y Medio Ambiente. In NIPO: 280-14-081-9.Martín-García, J., Solla, A., Corcobado, T., Siasou, E., & Woodward, S. (2015). Influence of temperature on germination of Quercus ilex in Phytophthora cinnamomi, P. gonapodyides, P. quercina and P. psychrophila infested soils. Forest Pathology, 45, 215–223.Maurel, M., Robin, C., Capron, G., & Desprez-Loustau, M. L. (2001). Effects of root damage associated with Phytophthora cinnamomi on water elations, biomass accumulation, mineral nutrition and vulnerability to water deficit of five oak and chestnut species. Forest Pathology, 31, 353–369.McKinney, H. H. (1923). Influence of soil temperature and moisture on infection of wheat seedlings by Helminthosporium sativum. Journal of Agricultural Research, 26, 195–217.Moralejo, E., Pérez-Sierra, A., Álvarez, L. A., Belbahri, L., Lefort, F., & Descals, E. (2009). Multiple alien Phytophthora taxa discovered on diseased ornamental plants in Spain. Plant Pathology, 58, 100–110.Mora-Sala, B., Berbegal, M., & Abad-Campos, P. (2018). The use of qPCR reveals a high frequency of Phytophthora quercina in two Spanish holm oak areas. Forests, 9(11):697. https://doi.org/10.3390/f9110697 .Moreira, A. C., & Martins, J. M. S. (2005). Influence of site factors on the impact of Phytophthora cinnamomi in cork oak stands in Portugal. Forest Pathology, 35, 145–162.Mrázková, M., Černý, K., Tomosovsky, M., Strnadová, V., Gregorová, B., Holub, V., Panek, M., Havrdová, L., & Hejná, M. (2013). Occurrence of Phytophthora multivora and Phytophthora plurivora in the Czech Republic. Plant Protection Science, 49, 155–164.Navarro, R. M., Gallo, L., Sánchez, M. E., Fernández, P., & Trapero, A. (2004). Efecto de distintas fertilizaciones de fósforo en la resistencia de brinzales de encina y alcornoque a Phytophthora cinnamomi Rands. Investigación Agraria. Sistemas y Recursos Forestales, 13, 550–558.Panabières, F., Ali, G., Allagui, M., Dalio, R., Gudmestad, N., Kuhn, M., Guha Roy, S., Schena, L., & Zampounis, A. (2016). Phytophthora nicotianae diseases worldwide: new knowledge of a long-recognised pathogen. Phytopathologia Mediterranea, 55, 20–40.Pérez-Sierra, A., & Jung, T. (2013). Phytophthora in woody ornamental nurseries. In: Phytophthora: A global perspective (pp. 166-177). Ed. by Lamour, K. Wallingford: CABI.Pérez-Sierra, A., Mora-Sala, B., León, M., García-Jiménez, J., & Abad-Campos, P. (2012). Enfermedades causadas por Phytophthora en viveros de plantas ornamentales. Boletín de Sanidad Vegetal-Plagas, 38, 143–156.Pérez-Sierra, A., López-García, C., León, M., García-Jiménez, J., Abad-Campos, P., & Jung, T. (2013). Previously unrecorded low-temperature Phytophthora species associated with Quercus decline in a Mediterranean forest in eastern Spain. Forest Pathology, 43, 331–339.Redondo, M. A., Pérez-Sierra, A., & Abad-Campos, P. (2015). Histology of Quercus ilex roots during infection by Phytophthora cinnamomi. Trees - Structure and Function, 29, 1943–5197.Ríos, P., Obregón, S., de Haro, A., Fernández-Rebollo, P., Serrano, M. S., & Sánchez, M. E. (2016). Effect of Brassica Biofumigant Amendments on Different Stages of the Life Cycle of Phytophthora cinnamomi. Journal of Phytopathology, 164, 582–594.Rizzo, D. M., Garbelotto, M., Davidson, J. M., Slaughter, G. W., & Koike, S. T. (2002). Phytophthora ramorum as the cause of extensive mortality of Quercus spp. and Lithocarpus densiflorus in California. Plant Disease, 86, 205–214.Robin, C., Desprez-Loustau, M. L., Capron, G., & Delatour, C. (1998). First record of Phytophthora cinnamomi on cork and holm oaks in France and evidence of pathogenicity. Annales Des Sciences Forestieres, 55, 869–883.Robin, C., Capron, G., & Desprez-Loustau, M. L. (2001). Root infection by Phytophthora cinnamomi in seedlings of three oak species. Plant Pathology, 50, 708–716.Rodríguez-Molina, M. C., Torres-Vila, L. M., Blanco-Santos, A., Núñez, E. J. P., & Torres-Álvarez, E. (2002). Viability of holm and cork oak seedlings from acorns sown in soils naturally infected with Phytophthora cinnamomi. Forest Pathology, 32, 365–372.Romero, M. A., Sánchez, J. E., Jiménez, J. J., Belbahri, L., Trapero, A., Lefort, F., & Sánchez, M. E. (2007). New Pythium taxa causing root rot in Mediterranean Quercus species in southwest Spain and Portugal. Journal of Phytopathology, 115, 289–295.Sánchez de Lorenzo-Cáceres J. M. (2001). Guía de las plantas ornamentales. S.A. Mundi-Prensa Libros. ISBN 9788471149374. 688 pp.Sánchez, M. E., Caetano, P., Ferraz, J., & Trapero, A. (2002). Phytophtora disease of Quercus ilex in south-western Spain. Forest Pathology, 32, 5–18.Sánchez, M. E., Sánchez, J. E., Navarro, R. M., Fernández, P., & Trapero, A. (2003). Incidencia de la podredumbre radical causada por Phytophthora cinnamomi en masas de Quercus en Andalucía. Boletín de Sanidad Vegetal-Plagas, 29, 87–108.Sánchez, M. E., Andicoberry, S., & Trapero, A. (2005). Pathogenicity of three Phytophthora spp. causing late seedling rot of Quercus ilex ssp. ballota. Forest Pathology, 35, 115–125.Sánchez, M. E., Caetano, P., Romero, M. A., Navarro, R. M., & Trapero, A. (2006). Phytophthora root rot as the main factor of oak decline in southern Spain. In: Progress in Research on Phytophthora Diseases of Forest Trees. Proceedings of the Third International IUFRO Working Party S07.02.09. Meeting at Freising. Germany 11-18 September 2004. Brasier C. M., Jung T., Oßwald W. (Eds). Forest Research. Farnham, UK. pp. 149-154.Scanu, B., Linaldeddu, B. T., Deidda, A., & Jung, T. (2015). Diversity of Phytophthora species from declining Mediterranean maquis vegetation, including two new species, Phytophthora crassamura and P. ornamentata sp. nov. PLoS ONE, 10. https://doi.org/10.1371/journal.pone.0143234 .Schmitthenner, A. F., & Canaday, C. H. (1983). Role of chemical factors in the development of Phytophthora diseases. In: Phytophthora. Its biology, taxonomy, ecology, and pathology (pp.189-196). Ed. by Erwin D. C., Bartnicki-Garcia S., Tsao P. H. St. Paul, : The American Phytopathological Society.Scibetta, S., Schena, L., Chimento, A., Cacciola, S. A., & Cooke, D. E. L. (2012). A molecular method to assess Phytophthora diversity in environmental samples. Journal of Microbiological Methods, 88, 356–368.Sena, K., Crocker, E., Vincelli, P., & Barton, C. (2018). Phytophthora cinnamomi as a driver of forest change: Implications for conservation and management. Forest Ecology and Management, 409, 799–807.Thines, M. (2013). Taxonomy and phylogeny of Phytophthora and related oomycetes In: Phytophthora: A global perspective (pp. 11-18). Ed. by Lamour, K. Wallingford: CABI.Tsao, P. H. (1990). Why many Phytophthora root rots and crown rots of tree and horticultural crops remain undetected. EPPO Bulletin, 20, 11–17.Tuset, J. J., Hinarejos, C., Mira, J. L., & Cobos, M. (1996). Implicación de Phytophthora cinnamomi Rands en la enfermedad de la seca de encinas y alcornoques. Boletín de Sanidad Vegetal-Plagas, 22, 491–499.Vettraino, A. M., Barzanti, G. P., Bianco, M. C., Ragazzi, A., Capretti, P., Paoletti, E., & Vannini, A. (2002). Occurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees. Forest Pathology, 32, 19–28.Xia, K., Hill, L. M., Li, D. Z., & Walters, C. (2014). Factors affecting stress tolerance in recalcitrant embryonic axes from seeds of four Quercus (Fagaceae) species native to the USA or China. Annals of Botany, 114, 1747–1759
Direct Identification of the Meloidogyne incognita Secretome Reveals Proteins with Host Cell Reprogramming Potential
The root knot nematode, Meloidogyne incognita, is an obligate parasite that causes significant damage to a broad range of host plants. Infection is associated with secretion of proteins surrounded by proliferating cells. Many parasites are known to secrete effectors that interfere with plant innate immunity, enabling infection to occur; they can also release pathogen-associated molecular patterns (PAMPs, e.g., flagellin) that trigger basal immunity through the nematode stylet into the plant cell. This leads to suppression of innate immunity and reprogramming of plant cells to form a feeding structure containing multinucleate giant cells. Effectors have generally been discovered using genetics or bioinformatics, but M. incognita is non-sexual and its genome sequence has not yet been reported. To partially overcome these limitations, we have used mass spectrometry to directly identify 486 proteins secreted by M. incognita. These proteins contain at least segmental sequence identity to those found in our 3 reference databases (published nematode proteins; unpublished M. incognita ESTs; published plant proteins). Several secreted proteins are homologous to plant proteins, which they may mimic, and they contain domains that suggest known effector functions (e.g., regulating the plant cell cycle or growth). Others have regulatory domains that could reprogram cells. Using in situ hybridization we observed that most secreted proteins were produced by the subventral glands, but we found that phasmids also secreted proteins. We annotated the functions of the secreted proteins and classified them according to roles they may play in the development of root knot disease. Our results show that parasite secretomes can be partially characterized without cognate genomic DNA sequence. We observed that the M. incognita secretome overlaps the reported secretome of mammalian parasitic nematodes (e.g., Brugia malayi), suggesting a common parasitic behavior and a possible conservation of function between metazoan parasites of plants and animals
- …