Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects

Nanjing, China

Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects

Nanjing, China
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Niu D.-D.,Nanjing Agricultural University | Niu D.-D.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Liu H.-X.,Nanjing Agricultural University | Liu H.-X.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | And 8 more authors.
Molecular Plant-Microbe Interactions | Year: 2011

Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces resistance against a broad spectrumof pathogens including Pseudomonas syringae pv. tomato DC3000. This study analyzed AR156-induced systemic resistance (ISR) to DC3000 in Arabidopsis ecotype Col-0 plants. Compared with mock-treated plants, AR156-treated ones showed an increase in biomass and reductions in disease severity and pathogen density in the leaves. The defense-related genes PR1, PR2, PR5, and PDF1.2 were concurrently expressed in the leaves of AR156-treated plants, suggesting simultaneous activation of the salicylic acid (SA)- and the jasmonic acid (JA)- and ethylene (ET)-dependent signaling pathways by AR156. The above gene expression was faster and stronger in plants treated with AR156 and inoculated with DC3000 than that in plants only inoculated with DC3000. Moreover, the cellular defense responses hydrogen peroxide accumulation and callose deposition were induced upon challenge inoculation in the leaves of Col-0 plants primed by AR156. Also, pretreatment with AR156 led to a higher level of induced protection against DC3000 in Col-0 than that in the transgenic NahG, the mutant jar1 or etr1, but the protection was absent in the mutant npr1. Therefore, AR156 triggers ISR in Arabidopsis by simultaneously activating the SA- and JA/ET-signaling pathways in an NPR1-dependent manner that leads to an additive effect on the level of induced protection. © 2011 The American Phytopathological Society.


Zhang H.,Nanjing Agricultural University | Zhang H.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Liu K.,Nanjing Agricultural University | Liu K.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | And 15 more authors.
PLoS ONE | Year: 2011

Cyclic AMP (cAMP) signaling plays an important role in regulating multiple cellular responses, such as growth, morphogenesis, and/or pathogenicity of eukaryotic organisms such as fungi. As a second messenger, cAMP is important in the activation of downstream effector molecules. The balance of intracellular cAMP levels depends on biosynthesis by adenylyl cyclases (ACs) and hydrolysis by cAMP phosphodiesterases (PDEases). The rice blast fungus Magnaporthe oryzae contains a high-affinity (PdeH/Pde2) and a low-affinity (PdeL/Pde1) PDEases, and a previous study showed that PdeH has a major role in asexual differentiation and pathogenicity. Here, we show that PdeL is required for asexual development and conidial morphology, and it also plays a minor role in regulating cAMP signaling. This is in contrast to PdeH whose mutation resulted in major defects in conidial morphology, cell wall integrity, and surface hydrophobicity, as well as a significant reduction in pathogenicity. Consistent with both PdeH and PdeL functioning in cAMP signaling, disruption of PDEH only partially rescued the mutant phenotype of ΔmagB and Δpka1. Further studies suggest that PdeH might function through a feedback mechanism to regulate the expression of pathogenicity factor Mpg1 during surface hydrophobicity and pathogenic development. Moreover, microarray data revealed new insights into the underlying cAMP regulatory mechanisms that may help to identify potential pathogenicity factors for the development of new disease management strategies. © 2011 Zhang et al.


Jin Z.P.,Nanjing Agricultural University | Jin Z.P.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Luo K.,Nanjing Agricultural University | Zhang S.,Nanjing Agricultural University | And 3 more authors.
Chemosphere | Year: 2012

Investigation on organic xenobiotics bioaccumulation/biodegradation in green algae is of great importance from environmental point of view because widespread distribution of these compounds in agricultural areas has become one of the major problems in aquatic ecosystem. Also, new technology needs to be developed for environmental detection and re-usage of the compounds as bioresources. Prometryne as a herbicide is widely used for killing annual grasses in China and other developing countries. However, overuse of the pesticide results in high risks to contamination to aquatic environments. In this study, we focused on analysis of bioaccumulation and degradation of prometryne in Chlamydomonas reinhardtii, a green alga, along with its adaptive response to prometryne toxicity. C. reinhardtii treated with prometryne at 2.5-12.5μgL -1 for 4d or 7.5μgL -1 for 1-6d accumulated a large quantity of prometryne, with more than 2mgkg -1 fresh weight in cells exposed to 10μgL -1 prometryne. Moreover, it showed a great ability to degrade simultaneously the cell-accumulated prometryne. Such uptake and catabolism of prometryne led to the rapid removal of prometryne from media. Physiological and molecular analysis revealed that toxicology was associated with accumulation of prometryne in the cells. The biological processes of degradation can be interpreted as an internal tolerance mechanism. These results suggest that the green alga is useful in bioremediation of prometryne-contaminated aquatic ecosystems. © 2012 Elsevier Ltd.


Jiang L.,Nanjing Agricultural University | Jiang L.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Ma L.,Nanjing Agricultural University | Sui Y.,Nanjing Agricultural University | And 5 more authors.
Journal of Hazardous Materials | Year: 2010

Soil amendment with manure compost may influence environmental behaviors and bioavailability of toxic organic chemicals (e.g. pesticide and polycyclic aromatic hydrocarbons). Dynamic parameters like adsorption, kinetics, mobility and degradation of pesticides have been intensively investigated. However, the current methods to evaluate the ultimate real bioavailability of pesticides to crops using physiochemical or biological approaches are limited. In this study, we developed a set of comprehensive and cost-effective parameters relevant to crop response to prometryne (s-triazine herbicide) to assess the accumulation and genotoxicity of the pesticide. Wheat plants exposed to 8mgkg-1 prometryne for 10 d showed stunt growth, reduced chlorophyll content and damaged membrane lipid. Concomitant treatment with 5% pig manure compost (PMC) alleviated the toxic effect on the plant. Prometryne in soils was readily accumulated by wheat. However, such an accumulation was significantly inhibited by PMC application. Because excessively accumulated prometryne triggered oxidative damage to plants, the biochemical responses of several antioxidant enzymes along with their molecular expressions were determined. In most cases, the activities and transcriptional expression of the enzymes were activated upon the exposure to prometryne but the process was prevented by PMC application. The set of biological parameters tested in this study were very sensitive and cost-effective, and therefore can be used to evaluate the degree of pesticide contamination to plants and other organisms. © 2010 Elsevier B.V.


Wu L.,Nanjing Agricultural University | Wu L.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Wu H.,Nanjing Agricultural University | Wu H.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | And 7 more authors.
Applied Microbiology and Biotechnology | Year: 2015

Bacillus amyloliquefaciens strains FZBREP and FZBSPA were derived from the wild-type FZB42 by replacement of the native bacilysin operon promoter with constitutive promoters PrepB and Pspac from plasmids pMK3 and pLOSS, respectively. These strains contained two antibiotic resistance genes, and markerless strains were constructed by deleting the chloramphenicol resistance cassette and promoter region bordered by two lox sites (lox71 and lox66) using Cre recombinase expressed from the temperature-sensitive vector pLOSS-cre. The vector-encoded spectinomycin resistance gene was removed by high temperature (50 °C) treatment. RT-PCR and qRT-PCR results indicated that PrepB and especially Pspac significantly increased expression of the bac operon, and FZBREP and FZBSPA strains produced up to 170.4 and 315.6 % more bacilysin than wild type, respectively. Bacilysin overproduction was accompanied by enhancement of the antagonistic activities against Staphylococcus aureus (an indicator of bacilysin) and Clavibacter michiganense subsp. sepedonicum (the causative agent of potato ring rot). Both the size and degree of ring rot-associated necrotic tubers were decreased compared with the wild-type strain, which confirmed the protective effects and biocontrol potential of these genetically engineered strains. © 2014, Springer-Verlag Berlin Heidelberg.


Yang Y.,Nanjing Agricultural University | Yang Y.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Wu H.-J.,Nanjing Agricultural University | Wu H.-J.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | And 7 more authors.
Applied Microbiology and Biotechnology | Year: 2015

According to the change of environment, soil-dwelling Bacillus species differentiate into distinct subpopulations, such as spores and competent cells. Rap-Phr systems have been found to be involved in this differentiation circuit by interacting with major regulatory proteins, such as Spo0A, ComA, and DegU. In this study, we report that the plasmid-born RapQ-PhrQ system found in Bacillus amyloliquefaciens B3 affects three regulatory pathways in the heterologous host Bacillus subtilis. Expression of rapQ in B. subtilis OKB105 strongly suppressed its sporulation efficiency, transformation efficiency, and surfactin production. Co-expression of phrQ or addition of synthesized PhrQ pentapeptide in vitro could compensate for the suppressive effects caused by rapQ. We also found that expression of rapQ decreased the transcriptional level of the sporulation-related gene spoIIE and surfactin synthesis-related gene srfA; meanwhile, the transcriptional levels of these genes could be rescued by co-expression of phrQ and in vitro addition of PhrQ pentapeptide. Electrophoretic mobility shift (EMSA) result also showed that RapQ could bind to ComA without interacting with ComA binding to DNA, and PhrQ pentapeptide antagonized RapQ activity in vitro. These results indicate that this new plasmid-born RapQ-PhrQ system controls sporulation, competent cell formation, and surfactin production in B. subtilis OKB105. © 2015, Springer-Verlag Berlin Heidelberg.


Gao K.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Gao K.,Nanjing Agricultural University | Xiong Q.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Xiong Q.,Nanjing Agricultural University | And 4 more authors.
Fungal Genetics and Biology | Year: 2013

Inhibitors of apoptosis proteins (IAPs) are critically important in the regulation of unicellular yeast and metazoan apoptosis. All IAPs contain one to three baculovirus IAP repeat (BIR) domains, which are essential for the anti-apoptotic activity of the IAPs. A homolog of IAPs, CpBir1, which bears two BIR domains, was recently identified from the chestnut blight fungus Cryphonectria parasitica genome. CpIAP was deleted by gene replacement, and the phenotypes of ΔIAP were characterized. CpBir1 was significantly down-regulated by hypovirus infection but up-regulated by H2O2. Similar to Saccharomyces cerevisiae Bir1p, the Cpbir1 mutant was sensitive to H2O2, and constitutive overexpression of CpBir1 increased resistance to H2O2. The Cpbir1 mutant also showed defects in aerial hyphal formation, colony growth, mycelial morphology, conidiogenesis, pigmentation, resistance to stress conditions and virulence. Genetic complementation with native Cpbir1 fully recovered all these defective phenotypes. The CpBir1-eGFP fusion protein was localized to the nucleus in juvenile cultures, while it was found in the cytoplasm in old cultures, suggesting that the localization pattern of CpBir1 may correlate with the process of anti-apoptosis. Increased accumulation of reactive oxygen species (ROS) in the Cpbir1 deletion mutant further supports the anti-apoptotic function of CpBir1. Among five selected vegetative compatible (vc) types of C. parasitica, Cpbir1 deletion was found to block virus from transferring between Cpbir1 mutants. However, hypovirus infected Cpbir1 mutants showed a similar ability to transmit virus to other virus-free isolates compared with the infected wild-type strain. In summary, Cpbir1 encodes an IAP CpBir1 that is down-regulated by hypovirus infection and required for conidiation, virulence and anti-apoptosis, as well as affects hypovirus transmission in chestnut blight fungus C. parasitica. © 2012 .


Duan Y.,Nanjing Agricultural University | Duan Y.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Duan Y.,Key Laboratory of Pesticide | Liu S.,Nanjing Agricultural University | And 14 more authors.
Pesticide Biochemistry and Physiology | Year: 2012

The necrotrophic fungal phytopathogen Sclerotinia sclerotiorum (Lib.) de Bary has a broad host range and frequently causes destructive diseases. The extensive use of common fungicides to control these diseases has selected for resistance in populations of S. sclerotiorum. In this study, 105 isolates of S. sclerotiorum from different geographical regions in Jiangsu Province of China were characterized for baseline sensitivity to azoxystrobin, and the average EC 50 value was 0.2932μg/mL for mycelial growth. Of the mixtures of the fungicides thiram and azoxystrobin that were tested using an in vitro mycelial growth assay, the 1:4 ratio provided the greatest inhibition of S. sclerotiorum. When tested against nine isolates, the 1:4 mixture resulted in a mean synergy ratio of 2.31, indicating synergistic inhibition. Mycelial respiration was inhibited for about 2h by azoxystrobin alone but for 48h by the mixture of thiram and azoxystrobin. Salicylhydroxamic acid (SHAM, a known inhibitor of alternative respiration) also increased the inhibition of mycelial growth and respiration caused by azoxystrobin. These results suggest the need for further study of effects of combinations of azoxystrobin with thiram or SHAM in planta to evaluate their potential for management of diseases caused by S. sclerotiorum. © 2012 Elsevier Inc.


Zhang H.,Nanjing Agricultural University | Zhang H.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | Liu K.,Nanjing Agricultural University | Liu K.,Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects | And 14 more authors.
Current Genetics | Year: 2010

A two-component signal transduction system is a common mechanism for environmental sensing in bacteria. The functions of the two-component molecules have been also well characterized in the lower eukaryotic fungi in recent years. In Saccharomyces cerevisiae, the histidine kinase Sln1p is a major component of the two-component signaling pathways and a key regulator of the osmolarity response. To determine the function of MoSLN1, a Sln1 homolog of Magnaporthe oryzae, we cloned the MoSLN1 gene and generated specific mutants using gene knock-out strategy. Disruption of MoSLN1 resulted in hypersensitivity to various stresses, reduced sensitivity to cell wall perturbing agent Calcofluor white, and loss of pathogenicity, mainly due to a penetration defect. Additionally, we showed that MoSLN1 is involved in oxidative signaling through modulation of intra- and extracellular peroxidase activities. These results indicate that MoSLN1 functions as a pathogenicity factor that plays a role in responses to osmotic stress, the cell wall integrity, and the activity of peroxidases. © 2010 Springer-Verlag.

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