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Peng H.,Chinese Academy of Agricultural Sciences | Qi X.,Chinese Academy of Agricultural Sciences | Peng D.,Chinese Academy of Agricultural Sciences | Long H.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | And 4 more authors.
Plant Disease | Year: 2013

Cereal cyst nematodes are the most important plant-parasitic nematodes on cereal crops in wheat producing areas of the world. Heterodera filipjevi was first reported in China in 2010. In this study, species-specific sequence characterized amplified region-polymerase chain reaction (SCAR-PCR) assays for detection and identification of H. filipjevi from infected wheat roots and soil were developed. The species-specific primers were designed according to the randomly amplified polymorphic DNA (RAPD) markers amplified with random primer OPK16. A 646-bp specific fragment of sequence was generated, which characterized amplified regions in H. filipjevi. The detection limitation of the PCR assay was as low as 0.125 μl second-stage juvenile (J2) lysate, 3.9 × 10-3 μl adult female lysate, and 10-3 μl cyst lysate. The method was able to detect the various stages (J2, J3, J4, and female) of H. filipjevi, and a single of nematode in 0.5 g of soil. H. filipjevi was detected by the method in two of six field samples, and one of those samples contained a mixed population of H. filipjevi and H. avenae. This study is the first to provide a definitive diagnostic assay for H. filipjevi in wheat roots and soil. © 2013 The American Phytopathological Society.


Peng H.,Chinese Academy of Agricultural Sciences | Peng D.,Chinese Academy of Agricultural Sciences | Long H.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Long H.,Chinese Academy of Sciences | And 4 more authors.
Nematology | Year: 2014

Plant-parasitic nematodes have developed a series of enzymes to degrade the rigid plant cell wall; β-1,4-endoglucanase is a very important component. Ditylenchus destructor is a migratory endoparasite for which few molecular data have been published. Two novel β-1,4-endoglucanases (Dd-eng-1a and Dd-eng-2) were cloned and characterised from D. destructor. The DD-ENG-1A putative protein consists of a signal peptide, a catalytic domain and a carbohydrate-binding module (CBM). By contrast, the CBM domain is absent from DD-ENG-2. The exon/intron structure and phylogenetic tree indicate that both cellulase genes could have evolved from common ancestral genes. Southern blotting confirmed that the β-1,4-endoglucanases were of nematode origin and a member of a small multi-gene family. In situ hybridisation localised the expression of Dd-eng-1a and Dd-eng-2 to the subventral pharyngeal glands. RT-PCR showed that both genes were expressed in the adult female and second-stage juvenile. The stylet secretions of D. destructor showed clear cellulase activity in carboxymethylcellulose (CMC) plate assay, and similar results were observed in total homogenates and DD-ENG-1A and DD-ENG-2 recombinant proteins. These results demonstrated that D. destructor can produce and secrete functional cellulases. Silencing the putative β-1,4-endoglucanases by double-stranded RNA (dsRNA) resulted in an average decrease in infection of 50%. Successful RNAi in vitro was demonstrated in this study, which confirmed that Dd-eng-1a and Dd-eng-2 play important roles in nematode parasitism. © Koninklijke Brill NV, Leiden, 2014.


Peng H.,Chinese Academy of Agricultural Sciences | Cui J.,Chinese Academy of Agricultural Sciences | Long H.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Long H.,Chinese Academy of Sciences | And 6 more authors.
PLoS ONE | Year: 2016

Pectate lyases are known to play a key role in pectin degradation by catalyzing the random cleavage of internal polymer linkages (endo-pectinases). In this paper, four novel cDNAs, designated Hg-pel-3, Hg-pel-4, Hg-pel-6 and Hg-pel-7, that encode pectate lyases were cloned and characterized from the soybean cyst nematode, Heterodera glycines. The predicted protein sequences of HG-PEL-3, HG-PEL-4 and HG-PEL-6 differed significantly in both their amino acid sequences and their genomic structures from other pectate lyases of H. glycines (HG-PEL-1, HG-PEL-2 and HG-PEL-7). A phylogenetic study revealed that the pectate lyase proteins of H. glycines are clustered into distinct clades and have distinct numbers and positioning of introns, which suggests that the pectate lyase genes of H. glycines may have evolved from at least two ancestral genes. A Southern blot analysis revealed that multiple Hg-pel-6-like genes were present in the H. glycines genome. In situ hybridization showed that four novel pectate lyases (Hg-pel-3, Hg-pel-4, Hg-pel-6 and Hgpel-7) were actively transcribed in the subventral esophageal gland cells. A semi-quantitative RT-PCR assay supported the finding that the expression of these genes was strong in the egg, pre-parasitic second-stage juvenile (J2) and early parasitic J2 stages and that it declined in further developmental stages of the nematode. This expression pattern suggests that these proteins play a role in the migratory phase of the nematode life cycle. Knocking down Hg-pel-6 using in vitro RNA interference resulted in a 46.9% reduction of the number of nematodes that invaded the plants and a 61.5% suppression of the development of H. glycines females within roots compared to the GFP-dsRNA control. Plant hostderived RNAi induced the silencing of the Hg-pel-6gene, which significantly reduced the nematode infection levels at 7 Days post inoculation (dpi). Similarly, this procedure reduced the number of female adults at 40 dpi, which suggests the important roles of this gene in the early stages of parasitism. Our combined data suggest that two types of pectate lyases are present in the H. glycines genome and may have different roles during infection. © 2016 Peng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Li Q.,Danzhou Agricultural Environmental Science Observation Laboratory | Li Q.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Zou Y.,Danzhou Agricultural Environmental Science Observation Laboratory | Zou Y.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | And 3 more authors.
Allelopathy Journal | Year: 2013

Precocene II is a major allelochemical produced by the weed Ageratum conyzoides. Its degradation is important in the recovery of A. conyzoides invaded plant communities. Using a strain of N. capsulatum isolated from the A. conyzoides invaded/infested soil; we examined the effects of various factors viz., incubation time, temperature, initial pH, and carbon and nitrogen source on the degradation of precocene II. We found that under optimal conditions with supplementation with a carbon and nitrogen source, up to 79.8% precocene II is degraded by N. capsulatum.


Lin Y.-Y.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Jin T.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Jin Q.-A.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Wen H.-B.,Key Laboratory of Pests Comprehensive Governance for Tropical crops | Peng Z.-Q.,Key Laboratory of Pests Comprehensive Governance for Tropical crops
Journal of Economic Entomology | Year: 2012

To present the susceptibility of Brontispa longissima (Gestro) (Coleoptera: Hispidae) to insecticides, 22 populations were collected in Southeast Asia from 2007 to 2010. Moreover, the laboratory susceptible strain was maintained. The results demonstrated that the lethal concentration50 value of the susceptible strain to avermectin, -cypermethrin, and acetamiprid was 0.034, 0.024, and 1.843 mg liter -1, respectively. Compared with the susceptible strain, 10 populations developed a medium level of resistance to avermectin (10.8-fold < resistance ratio [RR] < 34.7-fold) and 11 populations had low or minor resistance (3.6-fold

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