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1.
PLoS Pathog ; 16(1): e1008138, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31961913

RESUMO

Eukaryotic heterotrimeric guanine nucleotide-binding proteins consist of α, ß, and γ subunits, which act as molecular switches to regulate a number of fundamental cellular processes. In the oomycete pathogen Phytophthora sojae, the sole G protein α subunit (Gα; encoded by PsGPA1) has been found to be involved in zoospore mobility and virulence, but how it functions remains unclear. In this study, we show that the Gα subunit PsGPA1 directly interacts with PsYPK1, a serine/threonine protein kinase that consists of an N-terminal region with unknown function and a C-terminal region with a conserved catalytic kinase domain. We generated knockout and knockout-complemented strains of PsYPK1 and found that deletion of PsYPK1 resulted in a pronounced reduction in the production of sporangia and oospores, in mycelial growth on nutrient poor medium, and in virulence. PsYPK1 exhibits a cytoplasmic-nuclear localization pattern that is essential for sporangium formation and virulence of P. sojae. Interestingly, PsGPA1 overexpression was found to prevent nuclear localization of PsYPK1 by exclusively binding to the N-terminal region of PsYPK1, therefore accounting for its negative role in sporangium formation. Our data demonstrate that PsGPA1 negatively regulates sporangium formation by repressing the nuclear localization of its downstream kinase PsYPK1.


Assuntos
Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Phytophthora/enzimologia , Proteínas Serina-Treonina Quinases/metabolismo , Esporos/crescimento & desenvolvimento , Núcleo Celular/genética , Núcleo Celular/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/química , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Phytophthora/genética , Phytophthora/crescimento & desenvolvimento , Phytophthora/patogenicidade , Doenças das Plantas/parasitologia , Ligação Proteica , Domínios Proteicos , Transporte Proteico , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Soja/parasitologia , Esporos/enzimologia , Esporos/genética , Esporos/metabolismo , Virulência
2.
Plant Sci ; 289: 110271, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31623793

RESUMO

Soybean cyst nematode (Heterodera glycines Ichinohe) is a sedentary root endoparasite that causes serious yield losses on soybean (Glycine max) worldwide. H. glycines secrets effector proteins into host cells to facilitate the success of parasitism. Nowadays, a large number of candidate effectors were identified from the genome sequence of H. glycines. However, the precise functions of these effectors in the nematode-host plant interaction are unknown. Here, an effector gene of dorsal gland protein Hg16B09 from H. glycines was cloned and functionally characterized through generating the transgenic soybean hairy roots. In situ hybridization assay and qRT-PCR analysis indicated Hg16B09 is exclusively expressed in the dorsal esophageal cells and up-regulated in the parasitic-stage juveniles. The constitutive expression of Hg16B09 in soybean hairy roots caused an enhanced susceptibility to H. glycines. In contrast, in planta silencing of Hg16B09 exhibited that nematode reproduction in hairy roots was decreased compared to the empty vector control. In addition, Hg16B09 also suppressed the expression of soybean defense-related genes induced by the pathogen-associated molecular pattern flg22. These data indicate that the effector Hg16B09 might aid H. glycines parasitism through suppressing plant basal defenses in the early parasitic stages.


Assuntos
Proteínas de Helminto/genética , Doenças das Plantas/imunologia , Soja/imunologia , Tylenchoidea/fisiologia , Sequência de Aminoácidos , Animais , Proteínas de Helminto/química , Proteínas de Helminto/metabolismo , Doenças das Plantas/parasitologia , Imunidade Vegetal , Alinhamento de Sequência , Soja/parasitologia , Tylenchoidea/genética
3.
Phytopathology ; 109(12): 2096-2106, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31559903

RESUMO

Ethaboxam is a ß-tubulin inhibitor registered for the control of oomycete pathogens. The current study was established to determine the ethaboxam sensitivity of the plant pathogen Phytophthora sojae and investigate the potential for the emergence of fungicide resistance. The effective concentration for 50% inhibition (EC50) of 112 Phytophthora sojae isolates exhibited a unimodal distribution with a mean EC50 for ethaboxam of 0.033 µg/ml. Establishing this baseline sensitivity provided critical data for monitoring changes in ethaboxam-sensitivity in field populations. The potential for fungicide resistance was investigated using adaptation on ethaboxam-amended V8 agar, which resulted in the isolation of 20 resistant mutants. An assessment of the biological characteristics of the mutants including mycelial growth, sporulation, germination rate and pathogenicity indicated that the resistance risk in Phytophthora sojae was low to medium with no cross-resistance between ethaboxam and cymoxanil, metalaxyl, flumorph, and oxathiapiprolin being detected. However, positive cross-resistance was found between ethaboxam and zoxamide for Q8L and I258V but negative cross-resistance for C165Y. Further investigation revealed that the ethaboxam-resistant mutants had point mutations at amino acids Q8L, C165Y, or I258V of their ß-tubulin protein sequences. CRISPR/Cas9-mediated transformation experiments confirmed that the Q8L, C165Y, or I258V mutations could confer ethaboxam resistance in Phytophthora sojae and that the C165Y mutation induces high levels of resistance. Taken together, the results of the study provide essential data for monitoring the emergence of resistance and resistance management strategies for ethaboxam, as well as for improving the design of novel ß-tubulin inhibitors for future development.


Assuntos
Resistência a Medicamentos , Phytophthora , Mutação Puntual , Tiazóis , Tiofenos , Tubulina (Proteína) , Resistência a Medicamentos/genética , Phytophthora/efeitos dos fármacos , Phytophthora/genética , Doenças das Plantas/parasitologia , Soja/parasitologia , Tiazóis/farmacologia , Tiofenos/farmacologia , Tubulina (Proteína)/genética
4.
Int J Mol Sci ; 20(18)2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31540158

RESUMO

The mediator complex is an essential link between transcription factors and RNA polymerase II, and mainly functions in the transduction of diverse signals to genes involved in different pathways. Limited information is available on the role of soybean mediator subunits in growth and development, and their participation in defense response regulation. Here, we performed genome-wide identification of the 95 soybean mediator subunits, which were unevenly localized on the 20 chromosomes and only segmental duplication events were detected. We focused on GmMED16-1, which is highly expressed in the roots, for further functional analysis. Transcription of GmMED16-1 was induced in response to Phytophthora sojae infection. Agrobacterium rhizogenes mediated soybean hairy root transformation was performed for the silencing of the GmMED16-1 gene. Silencing of GmMED16-1 led to an enhanced susceptibility phenotype and increased accumulation of P. sojae biomass in hairy roots of transformants. The transcript levels of NPR1, PR1a, and PR5 in the salicylic acid defense pathway in roots of GmMED16-1-silenced transformants were lower than those of empty-vector transformants. The results provide evidence that GmMED16-1 may participate in the soybean-P. sojae interaction via a salicylic acid-dependent process.


Assuntos
Estudo de Associação Genômica Ampla , Interações Hospedeiro-Parasita/genética , Complexo Mediador/metabolismo , Phytophthora/fisiologia , Soja/genética , Soja/parasitologia , Mapeamento Cromossômico , Cromossomos de Plantas , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Filogenia , Phytophthora/classificação , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Subunidades Proteicas , Transcriptoma
5.
Mol Plant Microbe Interact ; 32(12): 1574-1576, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31415224

RESUMO

Phytophthora sojae is a significant pathogen of soybean worldwide. Pathotype surveys for Phytophthora sojae are conducted to monitor resistance gene efficacy and determine if new resistance genes are needed. Valuable measurements for pathotype analysis include the distribution of susceptible reactions, pathotype complexity, pathotype frequency, and diversity indices for pathotype distributions. Previously the Habgood-Gilmour Spreadsheet (HaGiS), written in Microsoft Excel, was used for data analysis. However, the growing popularity of the R programming language in plant pathology and desire for reproducible research made HaGiS a prime candidate for conversion into an R package. Here we report on the development and use of an R package, hagis, that can be used to produce all outputs from the HaGiS Excel sheet for P. sojae or other gene-for-gene pathosystem studies.


Assuntos
Parasitologia , Phytophthora , Software , Parasitologia/métodos , Soja/parasitologia
6.
Phytopathology ; 109(12): 2107-2115, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31403912

RESUMO

Cyst nematodes consistently threaten agricultural production, causing billions of dollars in losses globally. The Rhg1 (resistance to Heterodera glycines 1) locus of soybean (Glycine max) is the most popular resistance source used against soybean cyst nematodes (H. glycines). Rhg1 is a complex locus that has multiple repeats of an ≈30-kilobase segment carrying three genes that contribute to resistance. We investigated whether soybean Rhg1 could function in different plant families, conferring resistance to their respective cyst nematode parasites. Transgenic Arabidopsis thaliana and potato (Solanum tuberosum) plants expressing the three soybean Rhg1 genes were generated. The recipient Brassicaceae and Solanaceae plant species exhibited elevated resistance to H. schachtii and Globodera rostochiensis and to G. pallida, respectively. However, some negative consequences including reduced root growth and tuber biomass were observed upon Rhg1 expression in heterologous species. One of the genes at Rhg1 encodes a toxic version of an alpha-SNAP protein that has been demonstrated to interfere with vesicle trafficking. Using a transient expression assay for Nicotiana benthamiana, native Arabidopsis and potato alpha-SNAPs (soluble NSF [N-ethylamine sensitive factor] attachment protein) were found to compensate for the toxicity of soybean Rhg1 alpha-SNAP proteins. Hence, future manipulation of the balance between Rhg1 alpha-SNAP and the endogenous wild-type alpha-SNAPs (as well as the recently discovered soybean NSF-RAN07) may mitigate impacts of Rhg1 on plant productivity. The multispecies efficacy of soybean Rhg1 demonstrates that the encoded mechanisms can function across plant and cyst nematode species and offers a possible avenue for engineered resistance in diverse crop species.


Assuntos
Arabidopsis , Resistência à Doença , Plantas Geneticamente Modificadas , Solanum tuberosum , Soja , Tylenchoidea , Animais , Arabidopsis/genética , Arabidopsis/parasitologia , Resistência à Doença/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Solanum tuberosum/genética , Solanum tuberosum/parasitologia , Soja/genética , Soja/parasitologia , Tylenchoidea/fisiologia
7.
Pest Manag Sci ; 75(12): 3381-3391, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31282045

RESUMO

BACKGROUND: The soybean cyst nematode Heterodera glycines (Ichinohe) is the most devastating pathogen affecting soybean production worldwide. Biocontrol agents have become eco-friendly candidates to control pathogens. The aim of this study was to discover novel biocontrol agents against H. glycines. RESULTS: Microbacterium maritypicum Sneb159, screened from 804 strains, effectively reduced the number of females in field experiments conducted in 2014 and 2015. The stability and efficiency of H. glycines control by Sneb159 was further assessed in growth chamber and field experiments. Sneb159 decreased H. glycines population densities, especially the number of females by 43.9%-67.7%. To confirm Sneb159 induced plant resistance, a split-root assay was conducted. Sneb159 induced local and systemic resistance to suppress the penetration and development of H. glycines, and enhanced the gene expression of PR2, PR3b, and JAZ1, involved in the salicylic acid and jasmonic acid pathways. CONCLUSION: This is the first report of M. maritypicum Sneb159 suppressing H. glycines infection. This effect may be the result of Sneb159-induced resistance. Our study indicates that M. maritypicum Sneb159 is a promising biocontrol agent against H. glycines. © 2019 Society of Chemical Industry.


Assuntos
Actinobacteria/fisiologia , Agentes de Controle Biológico/farmacologia , Controle Biológico de Vetores , Doenças das Plantas/prevenção & controle , Soja/crescimento & desenvolvimento , Tylenchoidea/microbiologia , Animais , Expressão Gênica , Redes e Vias Metabólicas , Doenças das Plantas/parasitologia , Soja/parasitologia
8.
PLoS One ; 14(6): e0218217, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31194816

RESUMO

Integrating elements from life tables into population models within a matrix framework has been an underutilized method of describing host-parasitoid population dynamics. This type of modeling is useful in describing demographically-structured populations and in identifying points in the host developmental timeline susceptible to parasitic attack. We apply this approach to investigate the effect of parasitism by the Asian parasitoid Aphelinus certus on its host, the soybean aphid (Aphis glycines). We present a matrix population model with coupled equations that are analogous to a Nicholson-Bailey model. To parameterize the model, we conducted several bioassays outlining host and parasitoid life history and supplemented these studies with data obtained from the literature. Analysis of the model suggests that, at a parasitism rate of 0.21 d-1, A. certus is capable of maintaining aphid densities below economically damaging levels in 31.0% of simulations. Several parameters-parasitoid lifespan, colonization timeline, host developmental stage, and mean daily temperature-were also shown to markedly influence the overall dynamics of the system. These results suggest that A. certus might provide a valuable service in agroecosystems by suppressing soybean aphid populations at relatively low levels of parasitism. Our results also support the use of A. certus within a dynamic action threshold framework in order to maximize the value of biological control in pest management programs.


Assuntos
Afídeos/fisiologia , Interações Hospedeiro-Parasita , Himenópteros/fisiologia , Modelos Biológicos , Soja/parasitologia , Animais , Dinâmica Populacional
9.
PLoS One ; 14(6): e0218522, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31211798

RESUMO

Landscape complexity influences soybean aphid suppression by generalist predators in North America, but the role of adjacent habitats as sources of these predators has not been studied directly. We quantified movement of aphidophagous predators between soybean and five adjacent habitats common in Manitoba using bi-directional Malaise traps. To test the contribution of predators from neighboring habitats to soybean aphid suppression, we performed experimental manipulations in adjacent soybean and alfalfa fields and monitored the movement of sevenspotted lady beetles, Coccinella septempunctata, using mark-release-recapture experiments. The identity of adjacent habitats affected the net movement of predators into soybean. The most abundant predators were hover flies (Diptera: Syrphidae), moving from woodlands to soybean. Similar (but non-significant) trends were found for lady beetles, minute pirate bugs, and green and brown lacewings. There was also a net movement of hover flies and green lacewings from soybean to canola. Lady beetles showed higher bidirectional movement in alfalfa and wheat borders than in woodland and canola borders in a high lady beetle abundance year. Soybean aphid populations in predator exclusion cages were 21- to 122- fold higher than populations exposed to predators, both in alfalfa and soybean fields. Aerial predators provide similar levels of aphid suppression as aerial and epigeal predators combined. Mark-release-recapture experiments showed high dispersal of C. septempunctata between soybean and alfalfa, with a net movement towards alfalfa, probably due to the lack of aphids in soybean. These results demonstrate that predator assemblages from both soybeans and alfalfa can suppress soybean aphids. Our findings indicate that the type of adjacent habitat and predator identity affect the directionality of predator movement into soybean. This study suggests that information on predator movement can be used to design the distribution of crops and natural habitats in agricultural landscapes that maximize pest control services.


Assuntos
Afídeos , Ecossistema , Controle de Insetos , Comportamento Predatório , Soja/parasitologia , Animais
10.
BMC Res Notes ; 12(1): 325, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182145

RESUMO

OBJECTIVES: Soybean aphid (Aphis glycines Matsumura; SBA) is the most economically damaging insect of soybean (Glycine max) in the United States. One previous study demonstrated that avirulent (biotype 1) and virulent (biotype 2) biotypes could co-occur and interact on resistant (i.e., Rag1) and susceptible soybean resulting in induced susceptibility after 11 days of feeding. The main objective of this research was to employ RNA sequencing (RNA-seq) technique to compare the induced susceptibility effect of biotype 2 on susceptible and resistant soybean at day 1 and day 11 (i.e., both susceptible and resistant soybean were initially challenged by biotype 2 and the effect was monitored through biotype 1 populations). DATA DESCRIPTION: We investigated susceptible and Rag1 transcriptome response to SBA feeding in soybean plants colonized by biotype 1 in the presence or absence of an inducer population (i.e., biotype 2). Ten RNA datasets are reported with 266,535,654 sequence reads (55.2 GB) obtained from pooled samples derived from the leaves collected at day 1 and day 11 post SBA infestation. A comprehensive understanding of these transcriptome data will enhance our understanding of interactions among soybean and two different biotypes of soybean aphids at the molecular level.


Assuntos
Afídeos/fisiologia , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Parasita/genética , RNA de Plantas/genética , Soja/genética , Transcriptoma , Animais , Conjuntos de Dados como Assunto , Perfilação da Expressão Gênica , Herbivoria/fisiologia , Disseminação de Informação , Internet , Folhas de Planta/genética , Folhas de Planta/parasitologia , RNA de Plantas/metabolismo , Soja/parasitologia
11.
Plant Dis ; 103(8): 1876-1883, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161932

RESUMO

Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major pathogen of soybean [Glycine max (L.) Merr.] in the United States. The spatial distribution of SCN in 10 naturally infested research sites in North Dakota was examined between 2006 and 2009. Egg densities were measured in plots and expressed as arithmetic means or grouped into classes using two categorical scales based on the effect of SCN on yield. Data were used to determine spatial distribution, egg cluster sizes, minimum plot sizes, and replications in field experiments. SCN populations varied among plots from undetected to 25,800 eggs/100 cm3 of soil, and differences between adjacent plots were as high as sixfold. Mean to median ratios and Lloyd's index of patchiness suggested an aggregated distribution in nine of the 10 sites. SCN cluster sizes varied in five of the 10 sites and optimum plot size over all sites varied depending on calculation methods. The minimum number of replications needed to detect specific differences among plots varied between field sites. Grouping data into either of the two categories generally increased the ability to detect differences between plots. The spatial distribution of SCN can be a critical factor affecting design and outcomes of field experiments.


Assuntos
Doenças das Plantas , Soja , Tylenchoidea , Animais , North Dakota , Doenças das Plantas/parasitologia , Doenças das Plantas/estatística & dados numéricos , Soja/parasitologia , Tylenchoidea/fisiologia
12.
Theor Appl Genet ; 132(9): 2651-2662, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31230117

RESUMO

KEY MESSAGE: Soybean expressing small interfering RNA of SCN improved plant resistance to SCN consistently, and small RNA-seq analysis revealed a threshold of siRNA expression required for resistance ability. Soybean cyst nematode (SCN), Heterodera glycines, is one of the most destructive pests limiting soybean production worldwide, with estimated losses of $1 billion dollars annually in the USA alone. RNA interference (RNAi) has become a powerful tool for silencing gene expression. We report here that the expression of hairpin RNAi constructs, derived from two SCN genes related to reproduction and fitness, HgY25 and HgPrp17, enhances resistance to SCN in stably transformed soybean plants. The analyses of T3 to T5 generations of stable transgenic soybeans by molecular strategies and next-generation sequencing confirmed the presence of specific short interfering RNAs complementary to the target SCN genes. Bioassays performed on transgenic soybean lines targeting SCN HgY25 and HgPrp17 fitness genes showed significant reductions (up to 73%) for eggs/g root in the T3 and T4 homozygous transgenic lines. Targeted mRNAs of SCN eggs collected from the transgenic soybean lines were efficiently down-regulated, as confirmed by quantitative RT-PCR. Based on the small RNA-seq data and bioassays, it is our hypothesis that a threshold of small interfering RNA molecules is required to significantly reduce SCN populations feeding on the host plants. Our results demonstrated that host-derived gene silencing of essential SCN fitness genes could be an effective strategy for enhancing resistance in crop plants.


Assuntos
Resistência à Doença/genética , Inativação Gênica , Doenças das Plantas/genética , Proteínas de Plantas/genética , Soja/genética , Soja/parasitologia , Tylenchoidea/fisiologia , Animais , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Aptidão Genética , Ligação Genética , Marcadores Genéticos , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/parasitologia , Soja/metabolismo
13.
Theor Appl Genet ; 132(9): 2677-2687, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31250041

RESUMO

KEY MESSAGE: Three soybean candidate genes involved in resistance to soybean cyst nematode race 4 were identified via direct whole genome re-sequencing of two segregating mutants. The genes conferring resistance to soybean cyst nematode (SCN) race 4 (Hg type 1.2.3.5.7) in soybean (Glycine max L. Merr.) remains unknown. Next generation sequencing-based methods identify a wide range of targets, it is difficult to identify genes underlying traits. Use of the MutMap and QTL-seq methods to identify trait candidate genes needs backcrossing and is very time-consuming. Here we report a simple method to effectively identify candidate genes involved in resistance to SCN race 4. Two ethane methylsulfonate mutagenized mutants of soybean 'PI 437654', whose SCN race 4-infection phenotype altered, were selected. Six relevant whole genomes were re-sequenced, and then calling of genomic variants (SNPs and InDels) was conducted and compared to 'Williams 82'. The comparison eliminated many genomic variants from the mutant lines that overlapped two non-phenotypic but mutant progeny plants, wild-type PI 437654 and 'Zhonghuang 13'. Finally, only 27 mutations were found among 10 genes. Of these 10 genes, 3 genes, Glyma.09g054000, Glyma.16g065700 and Glyma.18g192200 were overlapped between two phenotypic mutant progeny plants. Therefore, the three genes may be the candidate genes involved in resistance of PI 437654 to soybean cyst nematode race 4. This method simplifies the effective identification of candidate genes.


Assuntos
Resistência à Doença/genética , Mutação , Doenças das Plantas/genética , Proteínas de Plantas/genética , Soja/genética , Tylenchoidea/fisiologia , Sequenciamento Completo do Genoma/métodos , Animais , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Ligação Genética , Marcadores Genéticos , Doenças das Plantas/parasitologia , Soja/metabolismo , Soja/parasitologia
14.
PLoS One ; 14(5): e0217130, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31125369

RESUMO

Heterodera glycines (soybean cyst nematode, SCN) is one of the most devastating pathogens of soybean worldwide. The compatible and in compatible interactions between soybean and SCN have well documented. Nevertheless, the molecular mechanism of a nonhost resistant response in soybean against SCN infection remains obscure. Toward this end, a global transcriptional comparison was conducted between susceptible and resistant reactions of soybean roots infected by taking advantage of finding a new pathotype of SCN (SCNT). The soybean cultivar Lee, which exhibits resistant to SCNT and susceptible to HG 1.2.3.4.7 (SCNs) was utilized in the expriments. The results highlighted a nonhost resistant response of soybean. Transcriptome analysis indicated that the number of differentially expressed genes (DEGs) in the resistant interaction (3746) was much larger than that in the susceptible interaction (602). A great number of genes acting as intrinsic component of membrane, integral component of membrane, cell periphery and plasma membrance were remarkably enriched only in the resistant interaction, while the taurine and hypotaurine, phenylpropanoid pathway, plant-pathogen interaction and transcript factors were modulated in both interactions. This is the first study to examine genes expression patterns in a soybean genotype in response to invasion by a virulent and avirulent SCN population at the transcriptional level, which will provide insights into the complicate molecular mechanism of the nonhost resistant interaction.


Assuntos
Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Parasita/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Soja/genética , Transcriptoma , Tylenchoidea/fisiologia , Animais , Doenças das Plantas/parasitologia , Proteínas de Plantas/metabolismo , Soja/parasitologia
15.
Int J Mol Sci ; 20(8)2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31013701

RESUMO

Phytophthora root rot (PRR) causes serious annual soybean yield losses worldwide. The most effective method to prevent PRR involves growing cultivars that possess genes conferring resistance to Phytophthora sojae (Rps). In this study, QTL-sequencing combined with genetic mapping was used to identify RpsX in soybean cultivar Xiu94-11 resistance to all P. sojae isolates tested, exhibiting broad-spectrum PRR resistance. Subsequent analysis revealed RpsX was located in the 242-kb genomic region spanning the RpsQ locus. However, a phylogenetic investigation indicated Xiu94-11 carrying RpsX is distantly related to the cultivars containing RpsQ, implying RpsX and RpsQ have different origins. An examination of candidate genes revealed RpsX and RpsQ share common nonsynonymous SNP and a 144-bp insertion in the Glyma.03g027200 sequence encoding a leucine-rich repeat (LRR) region. Glyma.03g027200 was considered to be the likely candidate gene of RpsQ and RpsX. Sequence analyses confirmed that the 144-bp insertion caused by an unequal exchange resulted in two additional LRR-encoding fragments in the candidate gene. A marker developed based on the 144-bp insertion was used to analyze the genetic population and germplasm, and proved to be useful for identifying the RpsX and RpsQ alleles. This study implies that the number of LRR units in the LRR domain may be important for PRR resistance in soybean.


Assuntos
Resistência à Doença/genética , Interações Hospedeiro-Parasita/genética , Phytophthora , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Soja/genética , Soja/parasitologia , Mapeamento Cromossômico , Cromossomos de Plantas , Sequência Conservada , Genes de Plantas , Ligação Genética , Loci Gênicos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Phytophthora/isolamento & purificação , Polimorfismo de Nucleotídeo Único , Soja/classificação
16.
PLoS One ; 14(3): e0214325, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30913247

RESUMO

Stink bugs (Hemiptera: Pentatomidae) are significant pests of cotton and soybeans in the southeastern United States with annual control costs exceeding $14 million in these crops. Three of the most prominent stink bug pests are the southern green (Nezara viridula), brown (Euschistus servus) and green (Chinavia hilaris) stink bugs. To determine trophic linkages between generalist arthropod predators and these pests, species-specific 16S molecular markers were designed and used to detect the presence of prey DNA in predator gut-contents. Over 2700 predators were collected over two growing seasons in cotton and soybean in southern Georgia in 2011 and 2012 and screened for stink bug DNA. Trophic linkages were analyzed relative to prey availability, crop type and field location. The frequency of stink bug DNA in predator guts was negligible on E. servus (0.23%) and C. hilaris (0.09%). Overall gut content detection of N. viridula was 3.3% and Geocoris sp. (Hemiptera: Geocoridae), Orius sp. (Hemiptera: Anthocoridae) and Notoxus monodon (Coleoptera: Anthicidae) were the primary predators. This contrasts with previous studies that reported a much more diverse suite of predators consuming stink bugs with much higher frequency of gut-content positives. The discrepancy between studies highlights the need for replicating studies in space and time, especially if the goal is to implement effective and durable conservation biological control in integrated pest management.


Assuntos
Gossypium/parasitologia , Hemípteros/fisiologia , Soja/parasitologia , Animais , Produtos Agrícolas , Hemípteros/genética , Mucosa Intestinal/metabolismo , Dinâmica Populacional , Comportamento Predatório , RNA Ribossômico 16S/genética , Especificidade da Espécie
17.
J Agric Food Chem ; 67(15): 4177-4183, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30920823

RESUMO

The kudzu bug, Megacopta cribraria, is a key pest of soybean in the United States. Electrophysiological and behavioral responses of adult M. cribraria to kudzu and soybean volatile compounds were examined to identify semiochemicals used for host location. Headspace volatiles collected from undamaged potted plants were analyzed by gas chromatography with electroantennographic detection (GC-EAD). Subsequently, six GC-EAD-active compounds were identified by gas chromatography-mass spectrometry (GC-MS). These six compounds, along with some previously reported insect attractants, were selected for electroantennogram (EAG) assays. The four chemicals that elicited the strongest EAG responses, 1-octen-3-ol, nonanal, benzaldehyde, and ocimene, were selected for evaluation in olfactometer bioassays. Both benzaldehyde and 1-octen-3-ol exhibited dose-dependent responses at higher concentration. Our results provide insight into host location compounds used by adult M. cribraria. These results may be evaluated in future field tests and ultimately useful to develop a semiochemical-based monitoring technique and integrated pest management program for M. cribraria.


Assuntos
Heterópteros/fisiologia , Pueraria/química , Soja/química , Compostos Orgânicos Voláteis/química , Animais , Quimiotaxia , Cromatografia Gasosa , Feminino , Odorantes/análise , Pueraria/parasitologia , Estações do Ano , Soja/parasitologia
18.
Transgenic Res ; 28(2): 257-266, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30830582

RESUMO

Phytophthora root and stem rot (PRR) caused by an oomycete pathogen Phytophthora sojae is one of the most devastating and widespread diseases throughout soybean-producing regions worldwide. The diversity and variability of P. sojae races make effective control of the pathogen challenging. Here, we introduced an elicitor of plant defense response, the harpinXooc-encoding hrf2 gene from the rice bacterial pathogen Xanthomonas oryzae pv. oryzicola into soybean and evaluated resistance to P. sojae infection. Molecular analysis confirmed the integration and expression of hrf2 in the transgenic soybean. After inoculation with P. sojae, non-transformed control (NC) plants exhibited typical PRR symptoms, including necrotic and wilting leaves, and plant death, whereas most of the transgenic plants showed slightly chlorotic leaves and developed normally. Through T3 to T5 generations, the transgenic events displayed milder disease symptoms and had higher survival rates compared to NC plants, indicating enhanced and stable resistance to P. sojae infection, whereas without P. sojae inoculation, no significant differences in agronomic traits were observed between the transgenic and non-transformed plants. Moreover, after inoculation with P. sojae, significant upregulation of a set of plant defense-related genes, including salicylic acid- and jasmonic acid-dependent and hypersensitive response-related genes was observed in the transgenic plants. Our results indicate that hrf2 expression in transgenic soybean significantly enhanced resistance to P. sojae by eliciting multiple defense responses mediated by different signaling pathways. The potential functional role of the hrf2 gene in plant defense against P. sojae and other pathogens makes it a promising tool for broadening disease resistance in soybean.


Assuntos
Resistência à Doença , Interações Hospedeiro-Parasita/genética , Phytophthora/patogenicidade , Doenças das Plantas/parasitologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/parasitologia , Soja/parasitologia , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Transdução de Sinais , Soja/genética , Soja/crescimento & desenvolvimento
19.
BMC Genomics ; 20(1): 119, 2019 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-30732586

RESUMO

BACKGROUND: Heterodera glycines, commonly referred to as the soybean cyst nematode (SCN), is an obligatory and sedentary plant parasite that causes over a billion-dollar yield loss to soybean production annually. Although there are genetic determinants that render soybean plants resistant to certain nematode genotypes, resistant soybean cultivars are increasingly ineffective because their multi-year usage has selected for virulent H. glycines populations. The parasitic success of H. glycines relies on the comprehensive re-engineering of an infection site into a syncytium, as well as the long-term suppression of host defense to ensure syncytial viability. At the forefront of these complex molecular interactions are effectors, the proteins secreted by H. glycines into host root tissues. The mechanisms of effector acquisition, diversification, and selection need to be understood before effective control strategies can be developed, but the lack of an annotated genome has been a major roadblock. RESULTS: Here, we use PacBio long-read technology to assemble a H. glycines genome of 738 contigs into 123 Mb with annotations for 29,769 genes. The genome contains significant numbers of repeats (34%), tandem duplicates (18.7 Mb), and horizontal gene transfer events (151 genes). A large number of putative effectors (431 genes) were identified in the genome, many of which were found in transposons. CONCLUSIONS: This advance provides a glimpse into the host and parasite interplay by revealing a diversity of mechanisms that give rise to virulence genes in the soybean cyst nematode, including: tandem duplications containing over a fifth of the total gene count, virulence genes hitchhiking in transposons, and 107 horizontal gene transfers not reported in other plant parasitic nematodes thus far. Through extensive characterization of the H. glycines genome, we provide new insights into H. glycines biology and shed light onto the mystery underlying complex host-parasite interactions. This genome sequence is an important prerequisite to enable work towards generating new resistance or control measures against H. glycines.


Assuntos
Evolução Molecular , Duplicação Gênica , Genômica , Soja/parasitologia , Tylenchoidea/genética , Tylenchoidea/fisiologia , Animais , Genótipo , Interações Hospedeiro-Parasita , Anotação de Sequência Molecular , Doenças das Plantas/parasitologia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA
20.
Plant Physiol Biochem ; 137: 25-41, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30711881

RESUMO

Mitogen activated protein kinases (MAPKs) play important signal transduction roles. However, little is known regarding how they influence the gene expression of other family members and the relationship to a biological process, including the Glycine max defense response to Heterodera glycines. Transcriptomics have identified MAPK gene expression occurring within root cells undergoing a defense response to a pathogenic event initiated by H. glycines in the allotetraploid Glycine max. Functional analyses are presented for its 32 MAPKs revealing 9 have a defense role, including homologs of Arabidopsis thaliana MAPK (MPK) MPK2, MPK3, MPK4, MPK5, MPK6, MPK13, MPK16 and MPK20. Defense signaling occurring through pathogen activated molecular pattern (PAMP) triggered immunity (PTI) and effector triggered immunity (ETI) have been determined in relation to these MAPKs. Five different types of gene expression relate to MAPK expression, influencing PTI and ETI gene expression and proven defense genes including an ABC-G transporter, 20S membrane fusion particle components, glycoside biosynthesis, carbon metabolism, hemicellulose modification, transcription and secretion. The experiments show MAPKs broadly influence defense MAPK gene expression, including the co-regulation of parologous MAPKs and reveal its relationship to proven defense genes. The experiments reveal each defense MAPK induces the expression of a G. max homolog of a PATHOGENESIS RELATED1 (PR1), itself shown to function in defense in the studied pathosystem.


Assuntos
Interações Hospedeiro-Parasita/fisiologia , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas de Plantas/genética , Soja/parasitologia , Tylenchoidea/patogenicidade , Animais , Regulação da Expressão Gênica de Plantas , Sistema de Sinalização das MAP Quinases , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Família Multigênica , Proteínas de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/parasitologia , Plantas Geneticamente Modificadas , Interferência de RNA , Soja/fisiologia
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