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Sample records for plant disease resistance

  1. Engineering disease resistance in plants

    NARCIS (Netherlands)

    Custers, J.H.H.V.

    2007-01-01

    The genetic engineering of plants for increased pathogen resistance has engaged researchers and companies for decades. Until now, thenumberof crops with genetically engineered disease resistance traits which have entered the market are limited to products displaying virus an

  2. Disease Resistance Gene Analogs (RGAs in Plants

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sekhwal

    2015-08-01

    Full Text Available Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs, as resistance (R gene candidates, have conserved domains and motifs that play specific roles in pathogens’ resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed.

  3. Disease Resistance Gene Analogs (RGAs) in Plants.

    Science.gov (United States)

    Sekhwal, Manoj Kumar; Li, Pingchuan; Lam, Irene; Wang, Xiue; Cloutier, Sylvie; You, Frank M

    2015-08-14

    Plants have developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs), as resistance (R) gene candidates, have conserved domains and motifs that play specific roles in pathogens' resistance. Well-known RGAs are nucleotide binding site leucine rich repeats, receptor like kinases, and receptor like proteins. Others include pentatricopeptide repeats and apoplastic peroxidases. RGAs can be detected using bioinformatics tools based on their conserved structural features. Thousands of RGAs have been identified from sequenced plant genomes. High-density genome-wide RGA genetic maps are useful for designing diagnostic markers and identifying quantitative trait loci (QTL) or markers associated with plant disease resistance. This review focuses on recent advances in structures and mechanisms of RGAs, and their identification from sequenced genomes using bioinformatics tools. Applications in enhancing fine mapping and cloning of plant disease resistance genes are also discussed.

  4. Signaling in Plant Disease Resistance and Symbiosis

    Institute of Scientific and Technical Information of China (English)

    Songzi Zhao; Xiaoquan Qi

    2008-01-01

    Interactions between plants and microbes result in plant disease and symbiosis. The former causes considerable economic damage in modern agriculture, while the latter has produced great beneficial effects to our agriculture system. Comparison of the two interactions has revealed that a common panel of signaling pathways might participate in the establishment of the equilibrium between plant and microbes or its break-up. Plants appear to detect both pathogenic and symbiotic microbes by a similar set of genes. All symbiotic microbes seem to produce effectors to overcome plant basal defenses and it is speculated that symbiotic effectors have functions similar to pathogenic ones. Signaling molecules, salicylic acid (SA),jasmonic acid (JA) and ethylene (ET), are involved in both plant defense and symbiosis. Switching off signals contributing to deterioration of disease symptom would establish a new equilibrium between plant and pathogenic microbes. This would facilitate the development of strategies for durable disease resistance.

  5. Induced disease resistance signaling in plants

    NARCIS (Netherlands)

    Verhagen, B.W.M.; Loon, L.C. van; Pieterse, C.M.J.

    2006-01-01

    To protect themselves from disease, plants have evolved sophisticated inducible defense mechanisms in which the signal molecules salicylic acid, jasmonic acid and ethylene often play crucial roles. Elucidation of signaling pathways controlling induced disease resistance is a major objective in resea

  6. The role of ethylene perception in plant disease resistance

    NARCIS (Netherlands)

    Geraats, Bart Peter Johan

    2003-01-01

    Ethylene is a plant hormone that is involved in responses of the plant to various stress situations, such as pathogen attack. The role of ethylene in plant-pathogen interactions seems to be diverse. Exposure of plants to ethylene can induce disease resistance, but treatment with ethylene during

  7. Molecular communications between plant heat shock responses and disease resistance.

    Science.gov (United States)

    Lee, Jae-Hoon; Yun, Hye Sup; Kwon, Chian

    2012-08-01

    As sessile, plants are continuously exposed to potential dangers including various abiotic stresses and pathogen attack. Although most studies focus on plant responses under an ideal condition to a specific stimulus, plants in nature must cope with a variety of stimuli at the same time. This indicates that it is critical for plants to fine-control distinct signaling pathways temporally and spatially for simultaneous and effective responses to various stresses. Global warming is currently a big issue threatening the future of humans. Reponses to high temperature affect many physiological processes in plants including growth and disease resistance, resulting in decrease of crop yield. Although plant heat stress and defense responses share important mediators such as calcium ions and heat shock proteins, it is thought that high temperature generally suppresses plant immunity. We therefore specifically discuss on interactions between plant heat and defense responses in this review hopefully for an integrated understanding of these responses in plants.

  8. Modulation of Phytoalexin Biosynthesis in Engineered Plants for Disease Resistance

    Directory of Open Access Journals (Sweden)

    Sylvain Cordelier

    2013-07-01

    Full Text Available Phytoalexins are antimicrobial substances of low molecular weight produced by plants in response to infection or stress, which form part of their active defense mechanisms. Starting in the 1950’s, research on phytoalexins has begun with biochemistry and bio-organic chemistry, resulting in the determination of their structure, their biological activity as well as mechanisms of their synthesis and their catabolism by microorganisms. Elucidation of the biosynthesis of numerous phytoalexins has permitted the use of molecular biology tools for the exploration of the genes encoding enzymes of their synthesis pathways and their regulators. Genetic manipulation of phytoalexins has been investigated to increase the disease resistance of plants. The first example of a disease resistance resulting from foreign phytoalexin expression in a novel plant has concerned a phytoalexin from grapevine which was transferred to tobacco. Transformations were then operated to investigate the potential of other phytoalexin biosynthetic genes to confer resistance to pathogens. Unexpectedly, engineering phytoalexins for disease resistance in plants seem to have been limited to exploiting only a few phytoalexin biosynthetic genes, especially those encoding stilbenes and some isoflavonoids. Research has rather focused on indirect approaches which allow modulation of the accumulation of phytoalexin employing transcriptional regulators or components of upstream regulatory pathways. Genetic approaches using gain- or less-of functions in phytoalexin engineering together with modulation of phytoalexin accumulation through molecular engineering of plant hormones and defense-related marker and elicitor genes have been reviewed.

  9. Genome-Editing Technologies for Enhancing Plant Disease Resistance

    Science.gov (United States)

    Andolfo, Giuseppe; Iovieno, Paolo; Frusciante, Luigi; Ercolano, Maria R.

    2016-01-01

    One of the greatest challenges for agricultural science in the 21st century is to improve yield stability through the progressive development of superior cultivars. The increasing numbers of infectious plant diseases that are caused by plant-pathogens make it ever more necessary to develop new strategies for plant disease resistance breeding. Targeted genome engineering allows the introduction of precise modifications directly into a commercial variety, offering a viable alternative to traditional breeding methods. Genome editing is a powerful tool for modifying crucial players in the plant immunity system. In this work, we propose and discuss genome-editing strategies and targets for improving resistance to phytopathogens. First of all, we present the opportunities to rewrite the effector-target sequence for avoiding effector-target molecular interaction and also to modify effector-target promoters for increasing the expression of target genes involved in the resistance process. In addition, we describe potential approaches for obtaining synthetic R-genes through genome-editing technologies (GETs). Finally, we illustrate a genome editing flowchart to modify the pathogen recognition sites and engineer an R-gene that mounts resistance to some phylogenetically divergent pathogens. GETs potentially mark the beginning of a new era, in which synthetic biology affords a basis for obtaining a reinforced plant defense system. Nowadays it is conceivable that by modulating the function of the major plant immunity players, we will be able to improve crop performance for a sustainable agriculture. PMID:27990151

  10. Plant-pathogen interactions: toward development of next-generation disease-resistant plants.

    Science.gov (United States)

    Nejat, Naghmeh; Rookes, James; Mantri, Nitin L; Cahill, David M

    2017-03-01

    Briskly evolving phytopathogens are dire threats to our food supplies and threaten global food security. From the recent advances made toward high-throughput sequencing technologies, understanding of pathogenesis and effector biology, and plant innate immunity, translation of these means into new control tools is being introduced to develop durable disease resistance. Effectoromics as a powerful genetic tool for uncovering effector-target genes, both susceptibility genes and executor resistance genes in effector-assisted breeding, open up new avenues to improve resistance. TALENs (Transcription Activator-Like Effector Nucleases), engineered nucleases and CRISPR (Clustered Regulatory Interspaced Short Palindromic Repeats)/Cas9 systems are breakthrough and powerful techniques for genome editing, providing efficient mechanisms for targeted crop protection strategies in disease resistance programs. In this review, major advances in plant disease management to confer durable disease resistance and novel strategies for boosting plant innate immunity are highlighted.

  11. Plant Resistance to Virus Diseases through Genetic Engineering: Can a Similar Approach Control Plant-parasitic Nematodes?

    OpenAIRE

    Reimann-Philipp, Ulrich; Beachy, Roger N.

    1993-01-01

    Genetically engineered resistance against plant virus diseases has been achieved by transforming plants with gene constructs that encode viral sequences. Several successful field trials of virus-resistant transgenic plants have been carried out. Specific features of virus infection make it possible to interfere with different steps of the infection and disease cycle by accumulating products of chimeric genes introduced into transgenic plants. In this paper we describe the most common methods ...

  12. Are stomatal responses the key to understanding the cost of fungal disease resistance in plants?

    Science.gov (United States)

    Withers, Catherine M; Gay, Alan P; Mur, Luis A J

    2011-07-01

    Preventing disease in cereal crops is important for maintaining productivity and as the availability and efficacy of chemical control becomes reduced the emphasis on breeding for disease resistance increases. However, there is evidence that disease resistance may be physiologically costly to the plant and we ask if understanding stomatal responses to fungal attack is the key to minimising reductions in growth associated with disease resistance.

  13. Overexpression of a Modified Plant Thionin Enhances Disease Resistance to Citrus Canker and Huanglongbing (HLB).

    Science.gov (United States)

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker.

  14. [Disease resistance signal transfer between roots of different tomato plants through common arbuscular mycorrhiza networks].

    Science.gov (United States)

    Xie, Li-Jun; Song, Yuan-Yuan; Zeng, Ren-Sen; Wang, Rui-Long; Wei, Xiao-Chen; Ye, Mao; Hu, Lin; Zhang, Hui

    2012-05-01

    Common mycorrhizal networks (CMNs) are the underground conduits of nutrient exchange between plants. However, whether the CMNs can serve as the underground conduits of chemical communication to transfer the disease resistance signals between plants are unknown. By inoculating arbuscular mycorrhizal fungus (AMF) Glomus mosseae to establish CMNs between 'donor' and 'receiver' tomato plants, and by inoculating Alternaria solani, the causal agent of tomato early blight disease, to the 'donor' plants, this paper studied whether the potential disease resistance signals can be transferred between the 'donor' and 'receiver' plants roots. The real time RT-PCR analysis showed that after inoculation with A. solani, the AMF-inoculated 'donor' plants had strong expression of three test defense-related genes in roots, with the transcript levels of the phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX) and chitinase (PR3) being significantly higher than those in the roots of the 'donor' plants only inoculated with A. solani, not inoculated with both A. solani and AMF, and only inoculated with AMF. More importantly, in the presence of CMNs, the expression levels of the three genes in the roots of the 'receiver' plants were significantly higher than those of the 'receiver' plants without CMNs connection, with the connection blocking, and with the connection but the 'donor' plants not A. solani-inoculated. Compared with the control (without CMNs connection), the transcript level of the PAL, LOX and PR3 in the roots of the 'receiver' plants having CMNs connection with the 'donor' plants was 4.2-, 4.5- and 3.5-fold higher, respectively. In addition, the 'donor' plants activated their defensive responses more quickly than the 'receiver' plants (18 and 65 h vs. 100 and 140 h). These findings suggested that the disease resistance signals produced by the pathogen-induced 'donor' tomato plant roots could be transferred to the 'receiver' plant roots through CMNs.

  15. Application of hordothionins and cecropin B for engineering bacterial disease resistance into plants.

    NARCIS (Netherlands)

    Florack, D.

    1994-01-01

    Bacterial diseases can cause a drastic decrease of yield in certain crops. Breeding for bacterial disease resistance therefore is of utmost necessity. Up to now, traditional plant breeding was the only method to reach this goal. Recent developments in genetic engineering technology however provide n

  16. Towards establishing broad-spectrum disease resistance in plants: silicon leads the way.

    Science.gov (United States)

    Van Bockhaven, Jonas; De Vleesschauwer, David; Höfte, Monica

    2013-03-01

    Plants are constantly threatened by a wide array of microbial pathogens. Pathogen invasion can lead to vast yield losses and the demand for sustainable plant-protection strategies has never been greater. Chemical plant activators and selected strains of rhizobacteria can increase resistance against specific types of pathogens but these treatments are often ineffective or even cause susceptibility against others. Silicon application is one of the scarce examples of a treatment that effectively induces broad-spectrum disease resistance. The prophylactic effect of silicon is considered to be the result of both passive and active defences. Although the phenomenon has been known for decades, very little is known about the molecular basis of silicon-afforded disease control. By combining knowledge on how silicon interacts with cell metabolism in diatoms and plants, this review describes silicon-induced regulatory mechanisms that might account for broad-spectrum plant disease resistance. Priming of plant immune responses, alterations in phytohormone homeostasis, regulation of iron homeostasis, silicon-driven photorespiration and interaction with defence signalling components all are potential mechanisms involved in regulating silicon-triggered resistance responses. Further elucidating how silicon exerts its beneficial properties may create new avenues for developing plants that are better able to withstand multiple attackers.

  17. Overexpression of a modified plant thionin enhances disease resistance to citrus canker and Huanglongbing (HLB

    Directory of Open Access Journals (Sweden)

    Guixia Hao

    2016-07-01

    Full Text Available Huanglongbing (HLB or citrus greening disease caused by Candidatus Liberibacter asiaticus (Las is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri. In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer twelve months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker.

  18. Genetic Engineering for Disease Resistance in Ornamental Plants

    Science.gov (United States)

    This symposium is intended to facilitate communication between researchers in Hungary, Romania, and other countries who are interested in micropropagation of ornamental plants. Some of the work that has been done in the Floral and Nursery Plants Research Unit that involves micropropagation is descr...

  19. Roles of small RNAs in plant disease resistance

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Hai Huang

    2014-01-01

    The interaction between plants and pathogens represents a dynamic competition between a robust immune system and efficient infectious strategies. Plant innate immunity is composed of complex and highly regulated molecular networks, which can be triggered by the perception of either conserved or race-specific pathogenic molecular signatures. Smal RNAs are emerging as versatile regulators of plant development, growth and response to biotic and abiotic stresses. They act in different tiers of plant immunity, including the pathogen-associated molecular pattern-triggered and the effector-triggered immunity. On the other hand, pathogens have evolved effector molecules to suppress or hijack the host smal RNA pathways. This leads to an arms race between plants and pathogens at the level of smal RNA-mediated defense. Here, we review recent advances in smal RNA-mediated defense responses and discuss the chal enging questions in this area.

  20. The genetic architecture of disease resistance in plants and the maintenance of recombination by parasites.

    Science.gov (United States)

    Kover, P X; Caicedo, A L

    2001-01-01

    Parasites represent strong selection on host populations because they are ubiquitous and can drastically reduce host fitness. It has been hypothesized that parasite selection could explain the widespread occurrence of recombination because it is a coevolving force that favours new genetic combinations in the host. A review of deterministic models for the maintenance of recombination reveals that for recombination to be favoured, multiple genes that interact with each other must be under selection. To evaluate whether parasite selection can explain the maintenance of recombination, we review 85 studies that investigated the genetic architecture of plant disease resistance and discuss whether they conform to the requirements that emerge from theoretical models. General characteristics of disease resistance in plants and problems in evaluating resistance experimentally are also discussed. We found strong evidence that disease resistance in plants is determined by multiple loci. Furthermore, in most cases where loci were tested for interactions, epistasis between loci that affect resistance was found. However, we found weak support for the idea that specific allelic combinations determine resistance to different host genotypes and there was little data on whether epistasis between resistance genes is negative or positive. Thus, the current data indicate that it is possible that parasite selection can favour recombination, but more studies in natural populations that specifically address the nature of the interactions between resistance genes are necessary. The data summarized here suggest that disease resistance is a complex trait and that environmental effects and fitness trade-offs should be considered in future models of the coevolutionary dynamics of host and parasites.

  1. Engineered plant virus resistance.

    Science.gov (United States)

    Galvez, Leny C; Banerjee, Joydeep; Pinar, Hasan; Mitra, Amitava

    2014-11-01

    Virus diseases are among the key limiting factors that cause significant yield loss and continuously threaten crop production. Resistant cultivars coupled with pesticide application are commonly used to circumvent these threats. One of the limitations of the reliance on resistant cultivars is the inevitable breakdown of resistance due to the multitude of variable virus populations. Similarly, chemical applications to control virus transmitting insect vectors are costly to the farmers, cause adverse health and environmental consequences, and often result in the emergence of resistant vector strains. Thus, exploiting strategies that provide durable and broad-spectrum resistance over diverse environments are of paramount importance. The development of plant gene transfer systems has allowed for the introgression of alien genes into plant genomes for novel disease control strategies, thus providing a mechanism for broadening the genetic resources available to plant breeders. Genetic engineering offers various options for introducing transgenic virus resistance into crop plants to provide a wide range of resistance to viral pathogens. This review examines the current strategies of developing virus resistant transgenic plants.

  2. Surveying the potential of secreted antimicrobial peptides to enhance plant disease resistance.

    Directory of Open Access Journals (Sweden)

    Susan eBreen

    2015-10-01

    Full Text Available Antimicrobial peptides (AMPs are natural products found across diverse taxa as part of the innate immune system against pathogen attacks. Some AMPs are synthesised through the canonical gene expression machinery and are called ribosomal AMPs. Other AMPs are assembled by modular enzymes generating nonribosomal AMPs and harbour unusual structural diversity. Plants synthesise an array of AMPs, yet are still subject to many pathogen invasions. Crop breeding programs struggle to release new cultivars in which complete disease resistance is achieved, and usually such resistance becomes quickly overcome by the targeted pathogens which have a shorter generation time. AMPs could offer a solution by exploring not only plant-derived AMPs, related or unrelated to the crop of interest, but also non-plant AMPs produced by bacteria, fungi, oomycetes or animals. This review highlights some promising candidates within the plant kingdom and elsewhere, and offers some perspectives on how to identify and validate their bioactivities. Technological advances, particularly in mass spectrometry (MS and nuclear magnetic resonance (NMR, have been instrumental in identifying and elucidating the structure of novel AMPs, especially nonribosomal peptides which cannot be identified through genomics approaches. The majority of non-plant AMPs showing potential for plant disease immunity are often tested using in vitro assays. The greatest challenge remains the functional validation of candidate AMPs in plants through transgenic experiments, particularly introducing nonribosomal AMPs into crops.

  3. Expression of Cryptogein in tobacco plants exhibits enhanced disease resistance and tolerance to salt stress

    Institute of Scientific and Technical Information of China (English)

    JIANG Donghua; CHEN Xujun; WU Kunlu; GUO Zejian

    2004-01-01

    Cryptogein (Crypt), an elicitin secreted from Phytophthora cryptogea, was used for genetic engineering of biotic and abiotic resistance plants. We generated transgenic tobacco plants harboring a rice phenylalanine ammonia-lyase (PAL) promoter and Crypt fusion gene (PAL::Crypt) or the mutated Crypt (mutation of the lysine at the position 13 to valine) under the control CaMV35S promoter (CaMV35S::CryK13V). T2 progeny of the transgenic plants showed significantly enhanced disease resistance to pathogens of fungal Phytophthora parasitica var nicotiana (Ppn) and Alternaria alternata, and bacterial Pseudomonas syringae pv tabaci. The amount of mRNA accumulation of Crypt and CryK13V was quite low in the transgenic lines analyzed by Northern blot, and was detected by a reverse transcription PCR method. Plants harboring PAL::Crypt construct showed faster and stronger induction of PR-1a gene after Ppn inoculation than that in the wild-type plants. The results suggested that the inducible PAL promoter could rapidly respond to pathogen attack and efficiently suppress the pathogen infection. Furthermore, the enhanced tolerance to salt stress in both of the Crypt and CryK13V expressing tobacco plants was also observed compared with that in the control plants. The constitutive expression of PR and transcription factor genes in the transformants was probably associated with the salt tolerance. The above observations suggested that a cross-talk between biotic and abiotic stresses existed in tobacco plants.

  4. Construction of biological control strain of Trichoderma viride and study of their ability to induce plant disease resistance

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-wang; GUO Ze-jian

    2004-01-01

    @@ Plant diseases heavily affct plant growth and crop yield even in modern agriculture. Control its difficult because pathogens mutate frequently, and this leads in frequent breaking of disease resistance in commercial cultivars. The excessive application of chemical pesticides is not only producing pesticideresistant pathogens, but it is harming the environment threatening the health of human beings.Therefore, the use of biological control agents (BCA) may provide an environmental friendly alternative to chemicals for plant disease control. Hypersensitive response (HR) and systemic acquired resistance (SAR) are the typical expressions of plant defense reactions. Once SAR is established,, the plants exhibits a broad-spectrum of disease resistance against pathogen attack. Researchers have identified elicitor proteins, such as elicitins and harpins, which activate plant defense reactions. It would be useful to explore the possibility of using biological control agents to induce a status of SAR in crop plants.

  5. An antibody that confers plant disease resistance targets a membrane-bound glyoxal oxidase in Fusarium.

    Science.gov (United States)

    Song, Xiu-Shi; Xing, Shu; Li, He-Ping; Zhang, Jing-Bo; Qu, Bo; Jiang, Jin-He; Fan, Chao; Yang, Peng; Liu, Jin-Long; Hu, Zu-Quan; Xue, Sheng; Liao, Yu-Cai

    2016-05-01

    Plant germplasm resources with natural resistance against globally important toxigenic Fusarium are inadequate. CWP2, a Fusarium genus-specific antibody, confers durable resistance to different Fusarium pathogens that infect cereals and other crops, producing mycotoxins. However, the nature of the CWP2 target is not known. Thus, investigation of the gene coding for the CWP2 antibody target will likely provide critical insights into the mechanism underlying the resistance mediated by this disease-resistance antibody. Immunoblots and mass spectrometry analysis of two-dimensional electrophoresis gels containing cell wall proteins from Fusarium graminearum (Fg) revealed that a glyoxal oxidase (GLX) is the CWP2 antigen. Cellular localization studies showed that GLX is localized to the plasma membrane. This GLX efficiently catalyzes hydrogen peroxide production; this enzymatic activity was specifically inhibited by the CWP2 antibody. GLX-deletion strains of Fg, F. verticillioides (Fv) and F. oxysporum had significantly reduced virulence on plants. The GLX-deletion Fg and Fv strains had markedly reduced mycotoxin accumulation, and the expression of key genes in mycotoxin metabolism was downregulated. This study reveals a single gene-encoded and highly conserved cellular surface antigen that is specifically recognized by the disease-resistance antibody CWP2 and regulates both virulence and mycotoxin biosynthesis in Fusarium species. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  6. The Genetics of Leaf Flecking in Maize and Its Relationship to Plant Defense and Disease Resistance.

    Science.gov (United States)

    Olukolu, Bode A; Bian, Yang; De Vries, Brian; Tracy, William F; Wisser, Randall J; Holland, James B; Balint-Kurti, Peter J

    2016-11-01

    Physiological leaf spotting, or flecking, is a mild-lesion phenotype observed on the leaves of several commonly used maize (Zea mays) inbred lines and has been anecdotally linked to enhanced broad-spectrum disease resistance. Flecking was assessed in the maize nested association mapping (NAM) population, comprising 4,998 recombinant inbred lines from 25 biparental families, and in an association population, comprising 279 diverse maize inbreds. Joint family linkage analysis was conducted with 7,386 markers in the NAM population. Genome-wide association tests were performed with 26.5 million single-nucleotide polymorphisms (SNPs) in the NAM population and with 246,497 SNPs in the association population, resulting in the identification of 18 and three loci associated with variation in flecking, respectively. Many of the candidate genes colocalizing with associated SNPs are similar to genes that function in plant defense response via cell wall modification, salicylic acid- and jasmonic acid-dependent pathways, redox homeostasis, stress response, and vesicle trafficking/remodeling. Significant positive correlations were found between increased flecking, stronger defense response, increased disease resistance, and increased pest resistance. A nonlinear relationship with total kernel weight also was observed whereby lines with relatively high levels of flecking had, on average, lower total kernel weight. We present evidence suggesting that mild flecking could be used as a selection criterion for breeding programs trying to incorporate broad-spectrum disease resistance. © 2016 American Society of Plant Biologists. All Rights Reserved.

  7. Thaxtomin A-deficient endophytic Streptomyces sp. enhances plant disease resistance to pathogenic Streptomyces scabies.

    Science.gov (United States)

    Lin, Lan; Ge, Hui Ming; Yan, Tong; Qin, Yan Hua; Tan, Ren Xiang

    2012-12-01

    Each plant species in nature harbors endophytes, a community of microbes living within host plants without causing any disease symptom. However, the exploitation of endophyte-based phytoprotectants is hampered by the paucity of mechanistic understandings of endophyte-plant interaction. We here reported two endophytic Streptomyces isolates IFB-A02 and IFB-A03 recovered from a stress-tolerant dicotyledonous plant Artemisia annua L. After the determination of their non-pathogenicity at the genomic level and from the toxin (thaxtomin A, TXT) level, the endophytism of both isolates was supported by their successful colonization in planta. Of the two endophytes, IFB-A03 was further studied for the mechanism of endophyte-conferred phytoprotection owing to its plant growth promotion in model eudicot Arabidopsis thaliana. Using the endophyte-Arabidopsis co-cultivation system into which pathogenic Streptomyces scabies was introduced, we demonstrated that IFB-A03 pre-inoculation could activate the salicylic acid (SA)-mediated plant defense responses upon pathogen challenge. Moreover, IFB-A03 was shown to partially rescue the defense deficiency in eds5 (enhanced disease susceptibility 5) Arabidopsis mutants, putatively acting at the upstream of SA accumulation in the defense signaling pathway associated with the systemic acquired resistance (SAR). These data suggest that endophytic Streptomyces sp. IFB-A03 could be a promising candidate for biocontrol agents against S. scabies--a causative pathogen of common scab diseases prevailing in agronomic systems.

  8. Scale-Dependent Assessment of Relative Disease Resistance to Plant Pathogens

    Directory of Open Access Journals (Sweden)

    Peter Skelsey

    2014-03-01

    Full Text Available Phenotyping trials may not take into account sufficient spatial context to infer quantitative disease resistance of recommended varieties in commercial production settings. Recent ecological theory—the dispersal scaling hypothesis—provides evidence that host heterogeneity and scale of host heterogeneity interact in a predictable and straightforward manner to produce a unimodal (“humpbacked” distribution of epidemic outcomes. This suggests that the intrinsic artificiality (scale and design of experimental set-ups may lead to spurious conclusions regarding the resistance of selected elite cultivars, due to the failure of experimental efforts to accurately represent disease pressure in real agricultural situations. In this model-based study we investigate the interaction of host heterogeneity and scale as a confounding factor in the inference from ex-situ assessment of quantitative disease resistance to commercial production settings. We use standard modelling approaches in plant disease epidemiology and a number of different agronomic scenarios. Model results revealed that the interaction of heterogeneity and scale is a determinant of relative varietal performance under epidemic conditions. This is a previously unreported phenomenon that could provide a new basis for informing the design of future phenotyping platforms, and optimising the scale at which quantitative disease resistance is assessed.

  9. Exploiting pathogens' tricks of the trade for engineering of plant disease resistance: challenges and opportunities.

    Science.gov (United States)

    Grant, Murray R; Kazan, Kemal; Manners, John M

    2013-05-01

    With expansion of our understanding of pathogen effector strategies and the multiplicity of their host targets, it is becoming evident that novel approaches to engineering broad-spectrum resistance need to be deployed. The increasing availability of high temporal gene expression data of a range of plant-microbe interactions enables the judicious choices of promoters to fine-tune timing and magnitude of expression under specified stress conditions. We can therefore contemplate engineering a range of transgenic lines designed to interfere with pathogen virulence strategies that target plant hormone signalling or deploy specific disease resistance genes. An advantage of such an approach is that hormonal signalling is generic so if this strategy is effective, it can be easily implemented in a range of crop species. Additionally, multiple re-wired lines can be crossed to develop more effective responses to pathogens.

  10. Effect of Seed Bacterization on Plant Growth Response and Induction of Disease Resistance in Chilli

    Institute of Scientific and Technical Information of China (English)

    Yasmeen Siddiqui; Sariah Meon

    2009-01-01

    This study aimed to examine the induction of disease resistance, and growth response in chilli plants elicited by plant growth promoting endophytic bacteria [Pseudomonas aeruginosa (UPMP3), Burkholderia cepacia (UPMB3), and Serratia marcescens (UPMS3)]. Seed bacterization with UPMP3 and UPMB3 significantly increased peroxidase (PO),polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities. This increase corresponded to greater reduction in pre- and post-emergence damping-off caused by Sclerotium rolfsii. UPMS3 alone or as mixture with UPMP3 and UPMB3 did not show any significant reduction in disease incidence. However, all the isolates tested did not inhibit the seed germination and seedling establishment in chilli.

  11. Understanding the involvement of rhizobacteria-mediated induction of systemic resistance in biocontrol of plant diseases

    OpenAIRE

    Bakker, P.A.H.M; Ran, L.X.; Pieterse, C. M. J.; Loon, L.C. van

    2003-01-01

    Specific strains of nonpathogenic rhizobacteria can induce systemic resistance that is effective against a range of plant pathogens. To exploit induced systemic resistance, detailed knowledge of the triggering bacterial traits involved and on signal transduction pathways in the plant is necessary. Possibilities to improve effectiveness of induced resistance by rhizobacterial strains are discussed.

  12. Effect of amino acid application on induced resistance against citrus canker disease in lime plants

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.

  13. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

    Directory of Open Access Journals (Sweden)

    Lori R Shapiro

    Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host-plant

  14. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

    Science.gov (United States)

    Shapiro, Lori R; Salvaudon, Lucie; Mauck, Kerry E; Pulido, Hannier; De Moraes, Consuelo M; Stephenson, Andrew G; Mescher, Mark C

    2013-01-01

    Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana) contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila) at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV). We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA) in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host-plant quality for (and

  15. Glyphosate Effects on Plant Mineral Nutrition, Crop Rhizosphere Microbiota, and Plant Disease in Glyphosate-Resistant Crops

    Science.gov (United States)

    2012-01-01

    Claims have been made recently that glyphosate-resistant (GR) crops sometimes have mineral deficiencies and increased plant disease. This review evaluates the literature that is germane to these claims. Our conclusions are: (1) although there is conflicting literature on the effects of glyphosate on mineral nutrition on GR crops, most of the literature indicates that mineral nutrition in GR crops is not affected by either the GR trait or by application of glyphosate; (2) most of the available data support the view that neither the GR transgenes nor glyphosate use in GR crops increases crop disease; and (3) yield data on GR crops do not support the hypotheses that there are substantive mineral nutrition or disease problems that are specific to GR crops. PMID:23013354

  16. [Antimicrobial activities of ant Ponericin W1 against plant pathogens in vitro and the disease resistance in its transgenic Arabidopsis].

    Science.gov (United States)

    Chen, Yong-Fang; Sun, Peng-Wei; Tang, Ding-Zhong

    2013-08-01

    The antimicrobial peptides (AMPs) exhibit a broad antimicrobial spectrum. The application of AMPs from non-plant organisms attracts considerable attention in plant disease resistance engineering. Ponericin W1, isolated from the venom of ant (Pachycondyla goeldii), shows antimicrobial activities against Gram-positive bacteria, Gram-negative bacteria and the budding yeast (Saccharomyces cerevisiae); however, it is not clear whether Ponericin W1 is effective against plant pathogens. The results of this study indicated synthesized Ponericin W1 inhibited mycelial growth of Magnaporthe oryzae and Botrytis cinerea, as well as hyphal growth and spore production of Fusarium graminearum. Besides, Ponericin W1 exhibited antibacterial activities against Pseudomonas syringae pv. tomato and Xanthomonas oryzae pv. oryzae. After codon optimization, Ponericin W1 gene was constructed into plant expression vector, and transformed into Arabidopsis thaliana by floral dip method. The Ponericin W1 was located in intercellular space of the transgenic plants as expected. Compared with the wild-type plants, there were ungerminated spores and less hyphal, conidia on the leaves of transgenic plants after innoculation with the powdery mildew fungus Golovinomyces cichoracearum. After innoculation with the pathogenic bac-terium Pseudomonas syringae pv. tomato, the baceria in the leaves of transgenic plants was significantly less than the wild-type plants, indicating that the transgenic plants displayed enhanced disease resistance to pathogens. These results demonstrate a potential use of Ponericin W1 in genetic engineering for broad-spectrum plant disease resistance.

  17. Transcriptomic Analyses on the Role of Nitric Oxide in Plant Disease Resistance.

    Science.gov (United States)

    Mata-Pérez, Capilla; Begara-Morales, Juan C; Luque, Francisco; Padilla, María N; Jiménez-Ruiz, Jaime; Sánchez-Calvo, Beatriz; Fierro-Risco, Jesús; Barroso, Juan B

    2016-01-01

    Nitric oxide (NO) is a gaseous molecule having key roles in many physiological processes such as germination, growth, development and senescence. It has been also shown the important role of NO as a signaling molecule in the response to a wide variety of stress situations, including both biotic and abiotic stress conditions. In the last few years, a growing number of studies have focused on NO-cell targets by several approaches such as transcriptomic and proteomic analyses. This review is centered on offering an update about the principal medium- and large-scale transcriptomic analyses performed with several NO donors including microarray, cDNA-amplification fragment length polymorphism (AFLP) and high throughput sequencing (RNA-seq technology) approaches mainly focused on the role of this reactive nitrogen species in relation to plant disease resistance. Different putative NO-responsive genes have been identified in different plant tissues and plant species by application of several NO donors suggesting the implication of NO-responsive genes with plant adaptive responses to biotic stress processes. Finally, it is also provided an overview about common transcription factor-binding sites of NO-responsive genes and the need to further analyze the different NO-targets by other omics studies.

  18. Proportional odds model applied to mapping of disease resistance genes in plants

    Directory of Open Access Journals (Sweden)

    Maria Helena Spyrides-Cunha

    2000-03-01

    Full Text Available Molecular markers have been used extensively to map quantitative trait loci (QTL controlling disease resistance in plants. Mapping is usually done by establishing a statistical association between molecular marker genotypes and quantitative variations in disease resistance. However, most statistical approaches require a continuous distribution of the response variable, a requirement not always met since evaluation of disease resistance is often done using visual ratings based on an ordinal scale of disease severity. This paper discusses the application of the proportional odds model to the mapping of disease resistance genes in plants amenable to expression as ordinal data. The model was used to map two resistance QTL of maize to Puccinia sorghi. The microsatellite markers bngl166 and bngl669, located on chromosomes 2 and 8, respectively, were used to genotype F2 individuals from a segregating population. Genotypes at each marker locus were then compared by assessing disease severity in F3 plants derived from the selfing of each genotyped F2 plant based on an ordinal scale severity. The residual deviance and the chi-square score statistic indicated a good fit of the model to the data and the odds had a constant proportionality at each threshold. Single-marker analyses detected significant differences among marker genotypes at both marker loci, indicating that these markers were linked to disease resistance QTL. The inclusion of the interaction term after single-marker analysis provided strong evidence of an epistatic interaction between the two QTL. These results indicate that the proportional odds model can be used as an alternative to traditional methods in cases where the response variable consists of an ordinal scale, thus eliminating the problems of heterocedasticity, non-linearity, and the non-normality of residuals often associated with this type of data.Marcadores moleculares têm sido extensivamente usados para o mapeamento de loci de

  19. Inducing resistance: a summary of papers presented at the First International Symposium on Induced Resistance to Plant Diseases, Corfu, May 2000

    NARCIS (Netherlands)

    Hammerschmidt, R.; Métraux, J.-P.; Loon, L.C. van

    2001-01-01

    The First International Symposium on Induced Resistance to Plant Diseases, organized by Eris Tjamos, brought together over 150 participants to discuss the complexities, questions and future direction of research on the mechanisms by which plants can become better able to defend themselves against pa

  20. Effectors as tools in disease resistance breeding against biotrophic, hemibiotrophic, and necrotrophic plant pathogens.

    Science.gov (United States)

    Vleeshouwers, Vivianne G A A; Oliver, Richard P

    2014-03-01

    One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. "Effectoromics" has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems.

  1. Comparative Genomics of Non-TNL Disease Resistance Genes from Six Plant Species.

    Science.gov (United States)

    Nepal, Madhav P; Andersen, Ethan J; Neupane, Surendra; Benson, Benjamin V

    2017-09-30

    Disease resistance genes (R genes), as part of the plant defense system, have coevolved with corresponding pathogen molecules. The main objectives of this project were to identify non-Toll interleukin receptor, nucleotide-binding site, leucine-rich repeat (nTNL) genes and elucidate their evolutionary divergence across six plant genomes. Using reference sequences from Arabidopsis, we investigated nTNL orthologs in the genomes of common bean, Medicago, soybean, poplar, and rice. We used Hidden Markov Models for sequence identification, performed model-based phylogenetic analyses, visualized chromosomal positioning, inferred gene clustering, and assessed gene expression profiles. We analyzed 908 nTNL R genes in the genomes of the six plant species, and classified them into 12 subgroups based on the presence of coiled-coil (CC), nucleotide binding site (NBS), leucine rich repeat (LRR), resistance to Powdery mildew 8 (RPW8), and BED type zinc finger domains. Traditionally classified CC-NBS-LRR (CNL) genes were nested into four clades (CNL A-D) often with abundant, well-supported homogeneous subclades of Type-II R genes. CNL-D members were absent in rice, indicating a unique R gene retention pattern in the rice genome. Genomes from Arabidopsis, common bean, poplar and soybean had one chromosome without any CNL R genes. Medicago and Arabidopsis had the highest and lowest number of gene clusters, respectively. Gene expression analyses suggested unique patterns of expression for each of the CNL clades. Differential gene expression patterns of the nTNL genes were often found to correlate with number of introns and GC content, suggesting structural and functional divergence.

  2. Activity against multidrug-resistant Mycobacterium tuberculosis in Mexican plants used to treat respiratory diseases.

    Science.gov (United States)

    Jimenez-Arellanes, Adelina; Meckes, Mariana; Ramirez, Raquel; Torres, Javier; Luna-Herrera, Julieta

    2003-09-01

    The increase of multidrug-resistant Mycobacterium tuberculosis (MDR-TB) demands the search for alternative antimycobacterial drugs. The aim of this study was to evaluate plants used in Mexican traditional medicine to treat respiratory diseases for activity against MDR-TB. A group of 22 plants was screened for activity against Mycobacterium tuberculosis H37Rv and Mycobacterium avium at concentrations from 50 to 200 microg/mL. The antimycobacterial effect was determined by a microcolorimetric assay with Alamar blue dye. None of the aqueous extracts had antimycobacterial activity. Hexane extracts from Artemisia ludoviciana, Chamaedora tepejilote, Lantana hispida, Juniperus communis and Malva parviflora, and methanol extracts from Artemisia ludoviciana and Juniperus communis inhibited the growth of Mycobacterium tuberculosis. Mycobacterium avium was inhibited by Juniperus communis hexane extract and by Malva parviflora methanol extract. The active extracts were tested against monoresistant variants of Mycobacterium tuberculosis H37Rv (isoniazid, rifampin, streptomycin and ethambutol resistant) and the hexane extract of Lantana hispida showed the best activity. Lantana hispida hexane extract was also active against a group of MDR-TB clinical isolates. In contrast, it did not inhibit the growth of non-tuberculous mycobacteria. The hexane extract of Lantana hispida was fractionated by column chromatography and one of its fractions (FVI) inhibited the growth of all the MDR-TB clinical isolates at concentrations up to 25 microg/mL. This study supports the fact that selecting plants by ethnobotanical criteria enhances the probability of finding species with activity against mycobacteria, and our results point to Lantana hispida as an important source of potential compounds against MDR-TB.

  3. Effectors as Tools in Disease Resistance Breeding Against Biotrophic, Hemibiotrophic, and Necrotrophic Plant Pathogens

    NARCIS (Netherlands)

    Vleeshouwers, V.G.A.A.; Oliver, R.P.

    2014-01-01

    One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of

  4. Structure-function analysis of the NB-ARC domain of plant disease resistance proteins

    NARCIS (Netherlands)

    van Ooijen, G.; Mayr, G.; Kasiem, M.M.A.; Albrecht, M.; Cornelissen, B.J.C.; Takken, F.L.W.

    2008-01-01

    Resistance (R) proteins in plants are involved in pathogen recognition and subsequent activation of innate immune responses. Most resistance proteins contain a central nucleotide-binding domain. This so-called NB-ARC domain consists of three subdomains: NB, ARC1, and ARC2. The NB-ARC domain is a fun

  5. Loss of CMD2‐mediated resistance to cassava mosaic disease in plants regenerated through somatic embryogenesis

    Science.gov (United States)

    Chauhan, Raj Deepika; Wagaba, Henry; Moll, Theodore; Alicai, Titus; Miano, Douglas; Carrington, James C.; Taylor, Nigel J.

    2016-01-01

    Summary Cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are the two most important viral diseases affecting cassava production in Africa. Three sources of resistance are employed to combat CMD: polygenic recessive resistance, termed CMD1, the dominant monogenic type, named CMD2, and the recently characterized CMD3. The farmer‐preferred cultivar TME 204 carries inherent resistance to CMD mediated by CMD2, but is highly susceptible to CBSD. Selected plants of TME 204 produced for RNA interference (RNAi)‐mediated resistance to CBSD were regenerated via somatic embryogenesis and tested in confined field trials in East Africa. Although micropropagated, wild‐type TME 204 plants exhibited the expected levels of resistance, all plants regenerated via somatic embryogenesis were found to be highly susceptible to CMD. Glasshouse studies using infectious clones of East African cassava mosaic virus conclusively demonstrated that the process of somatic embryogenesis used to regenerate cassava caused the resulting plants to become susceptible to CMD. This phenomenon could be replicated in the two additional CMD2‐type varieties TME 3 and TME 7, but the CMD1‐type cultivar TMS 30572 and the CMD3‐type cultivar TMS 98/0505 maintained resistance to CMD after passage through somatic embryogenesis. Data are presented to define the specific tissue culture step at which the loss of CMD resistance occurs and to show that the loss of CMD2‐mediated resistance is maintained across vegetative generations. These findings reveal new aspects of the widely used technique of somatic embryogenesis, and the stability of field‐level resistance in CMD2‐type cultivars presently grown by farmers in East Africa, where CMD pressure is high. PMID:26662210

  6. Sucrose-mediated priming of plant defense responses and broad-spectrum disease resistance by overexpression of the maize pathogenesis-related PRms protein in rice plants.

    Science.gov (United States)

    Gómez-Ariza, Jorge; Campo, Sonia; Rufat, Mar; Estopà, Montserrat; Messeguer, Joaquima; San Segundo, Blanca; Coca, María

    2007-07-01

    Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.

  7. Rapid cloning of disease-resistance genes in plants using mutagenesis and sequence capture

    Science.gov (United States)

    Genetic solutions to protect crops against pests and pathogens are preferable to agrichemicals 1. Wild crop relatives carry immense diversity of disease resistance (R) genes that could enable more sustainable disease control. However, recruiting R genes for crop improvement typically involves long b...

  8. Toward a quarter century of pathogen-derived resistance and practical approaches to plant virus disease control.

    Science.gov (United States)

    Gottula, J; Fuchs, M

    2009-01-01

    The concept of pathogen-derived resistance (PDR) describes the use of genetic elements from a pathogen's own genome to confer resistance in an otherwise susceptible host via genetic engineering [J. Theor. Biol. 113 (1985) 395]. Illustrated with the bacteriophage Qbeta in Escherichia coli, this strategy was conceived as a broadly applicable approach to engineer resistance against pathogens. For plant viruses, the concept of PDR was validated with the creation of tobacco plants expressing the coat protein gene of Tobacco mosaic virus (TMV) and exhibiting resistance to infection by TMV [Science 232 (1986) 738]. Subsequently, virus-resistant horticultural crops were developed through the expression of viral gene constructs. Among the numerous transgenic crops produced and evaluated in the field, papaya resistant to Papaya ringspot virus (PRSV) [Annu. Rev. Phytopathol. 36 (1998) 415] and summer squash resistant to Cucumber mosaic virus (CMV), Zucchini yellow mosaic virus, and/or Watermelon mosaic virus [Biotechnology 13 (1995) 1458] were released for commercial use in the USA. Although cultivated on limited areas, the adoption rate of cultivars derived from these two crops is increasing steadily. Tomato and sweet pepper resistant to CMV and papaya resistant to PRSV were also released in the People's Republic of China. Applying the concept of PDR provides unique opportunities for developing virus-resistant crops and implementing efficient and environmentally sound management approaches to mitigate the impact of virus diseases. Based on the tremendous progress made during the past quarter century, the prospects of further advancing this innovative technology for practical control of virus diseases are very promising.

  9. [Mechanism of tomato plants enhanced disease resistance against early blight primed by arbuscular mycorrhizal fungus Glomus versiforme].

    Science.gov (United States)

    Song, Yuan-yuan; Wang, Rui-long; Wei, Xiao-chen; Lu, Yong-jian; Tang, Zhao-yang; Wu, Guo-zhao; Su, Yi-juan; Zeng, Ren-sen

    2011-09-01

    Arbuscular mycorrhiza (AM) can not only improve host plants nutrient absorption, but also enhance their disease resistance. Taking the tomato (Lycopersicon esculentum) seedlings preinoculated with axbuscular mycorrhizal fungus (AMF) Glomus versiforme as test materials, this paper studied their protective enzyme activities and defense-related genes expression, and their resistance against a fungal pathogen Alternaria solani Sorauer which causes early blight. The seedlings pre-inoculated with AMF and later inoculated with A. solani showed significantly higher activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves. The leaf SOD activity of the dually inoculated plants reached the maximum 18 h after pathogen inoculation, being 28.6%, 79.2% and 82.8% higher than that of the plants with G. versiforme inoculation alone, pathogen inoculation alone, and non-inoculation, and the Leaf POD activity reached the maximum 65 h after pathogen inoculation, being 762%, 18.3%, and 1710% higher, respectively. Real time RT-PCR analysis showed that dual inoculation with C. versiforme and A. solani strongly induced the expression of three defense-related genes. The transcript levels of pathogen-related protein (PR1), basic type beta-1,3-glucanase (PR-2), and chitinase (PR-3) in leaves were 9.67-, 8.54-, and 13.4-fold higher, as compared with the non-inoculation control, respectively. Bioassay showed that the disease incidence and disease index of the seedlings pre-inoculated with C. versiforme were reduced by 36.3% and 61.4%, respectively, as compared with the non-mycorrhizal control plants. These findings indicated that mycorrhizal colonization could induce stronger and quicker defense responses of host tomato plants, and priming could be an important mechanism of the enhanced disease resistance of mycorrhizal tomato plants.

  10. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yoshiteru eNoutoshi

    2012-10-01

    Full Text Available Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened 2 different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds—sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine—among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 µM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.

  11. Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae.

    Science.gov (United States)

    Wang, Zhenzhen; Han, Qiang; Zi, Qian; Lv, Shun; Qiu, Dewen; Zeng, Hongmei

    2017-01-01

    Exogenous application of the protein elicitors MoHrip1 and MoHrip2, which were isolated from the pathogenic fungus Magnaporthe oryzae (M. oryzae), was previously shown to induce a hypersensitive response in tobacco and to enhance resistance to rice blast. In this work, we successfully transformed rice with the mohrip1 and mohrip2 genes separately. The MoHrip1 and MoHrip2 transgenic rice plants displayed higher resistance to rice blast and stronger tolerance to drought stress than wild-type (WT) rice and the vector-control pCXUN rice. The expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes was also increased, suggesting that these two elicitors may trigger SA signaling to protect the rice from damage during pathogen infection and regulate the ABA content to increase drought tolerance in transgenic rice. Trypan blue staining indicated that expressing MoHrip1 and MoHrip2 in rice plants inhibited hyphal growth of the rice blast fungus. Relative water content (RWC), water usage efficiency (WUE) and water loss rate (WLR) were measured to confirm the high capacity for water retention in transgenic rice. The MoHrip1 and MoHrip2 transgenic rice also exhibited enhanced agronomic traits such as increased plant height and tiller number.

  12. EFFECTS OF LATE BLIGHT RESISTANT POTATO CONTAINING RB GENE ON THE SOIL MICROBES, PESTS AND PLANT DISEASES

    Directory of Open Access Journals (Sweden)

    Eny Ida Riyanti

    2014-10-01

    Full Text Available Late blight caused by Phytophthora infestans is an important disease on potato.  Several potato hybrids have been generated by crossing local varieties (Atlantic and Granola with Katahdin SP951 which contains late blight resistance gene RB.  Prior to release, these hybrids need to be evaluated for their environ-mental effects on non-target organisms and natural pests and diseases. The objectives of the study were to investigate the effect of LBR potato hybrids on beneficial soil microbes, pests and diseases. The trial was conducted in the confined field trial (CFT in Lembang, West Java. The parental non-transgenic (NT clones (Granola, Atlantic and Katahdin and LBR hybrids (four clones of Atlantic x Katahdin SP951 hybrids; 10 clones of Granola x Katahdin SP951 were planted at a plant spacing of 30 cm x 70 cm. Fungicide applications were used as treat-ments (no spray, five and twenty times sprays. The experi-ment was arranged in a randomized completely block design with three replications. The parameters determined were popula-tions of N2 fixing and P solubilizing bacteria, soil C/N ratio as well as natural pests and diseases. The results showed that the transgenic LBR potato hybrids did not have negative effect on N fixing bacteria. The bacterial populations were around 1010-11 cells g-1 soil before planting, 1012 cells at 1.5 months after planting (MAP and 108 cells after harvest. For P- solubilizing bacteria, their populations were 1010 cells before planting, 1012 cells at 1.5 MAP and 1011 cells g-1  soil after harvest. The soil C/N ratio of the transgenic plot was not statistically different compared to non-transgenic plot, i.e. 12-15 before planting, 10-11 at 1.5 MAP, and 10 after harvest in non-spray plot. Pests and diseases such as Alternaria solani, Liriomyza, potato tubber moth, aphid and mites on the transgenic and non-transgenic plots were statistically not different. The resistance score for A. solani was 7.2 (parental tansgenic and

  13. [Modulation of plant resistance to diseases by water-soluble chitosan].

    Science.gov (United States)

    Vasiukova, N I; Zinov'eva, S V; Il'inskaia, L I; Perekhod, E A; Chalenko, G I; Gerasimova, N G; Il'ina, A V; Varlamov, V P; Ozeretskovskaia, O L

    2001-01-01

    Low-molecular-weight water-soluble chitosan with a molecular weight of 5 kDa obtained after enzymatic hydrolysis of native crab chitosan was shown to display an elicitor activity by inducing the local and systemic resistance of Solanumi tuberosum potato and Lycopesicon esculentum tomato to Phytophthora infestans and nematodes, respectively. Chitosan induced the accumulation of phytoalexins in tissues of host plants, decreased the total content and changed the composition of free sterols producing adverse effects on infesters, activated chitinases, beta-glucanases, and lipoxygenases, and stimulated the generation of reactive oxygen species. The activation of protective mechanisms in plant tissues inhibited the growth of taxonomically different pathogens (parasitic fungus Phytophthora infestans and root knot nematode Meloidogyne incognita).

  14. Achieving Durable Resistance Against Plant Diseases: Scenario Analyses with a National-Scale Spatially Explicit Model for a Wind-Dispersed Plant Pathogen.

    Science.gov (United States)

    Elisabeth Lof, Marjolein; de Vallavieille-Pope, Claude; van der Werf, Wopke

    2017-05-01

    Genetic resistance in crops is a cornerstone of disease management in agriculture. Such genetic resistance is often rapidly broken due to selection for virulence in the pathogen population. Here, we ask whether there are strategies that can prolong the useful life of plant resistance genes. In a modeling study, we compared four deployment strategies: gene pyramiding, sequential use, simultaneous use, and a mixed strategy. We developed a spatially explicit model for France and parameterized it for the fungal pathogen Puccinia striiformis f. sp. tritici (causing wheat yellow rust) to test management strategies in a realistic spatial setting. We found that pyramiding two new resistance genes in one variety was the most durable solution only when the virulent genotype had to emerge by mutation. Deploying single-gene-resistant varieties concurrently with the pyramided variety eroded the durability of the gene pyramid. We found that continuation of deployment of varieties with broken-down resistance prolonged the useful life of simultaneous deployment of four single-gene-resistant varieties versus sequential use. However, when virulence was already present in the pathogen population, durability was low and none of the deployment strategies had effect. These results provide guidance on effective strategies for using resistance genes in crop protection practice.

  15. Silicon in plant disease control

    Directory of Open Access Journals (Sweden)

    Edson Ampélio Pozza

    2015-06-01

    Full Text Available All essential nutrients can affect the incidence and severity of plant diseases. Although silicon (Si is not considered as an essential nutrient for plants, it stands out for its potential to decrease disease intensity in many crops. The mechanism of Si action in plant resistance is still unclear. Si deposition in plant cell walls raised the hypothesis of a possible physical barrier to pathogen penetration. However, the increased activity of phenolic compounds, polyphenol oxidases and peroxidases in plants treated with Si demonstrates the involvement of this element in the induction of plant defense responses. The studies examined in this review address the role of Si in disease control and the possible mechanisms involved in the mode of Si action in disease resistance in plants.

  16. Synthesis of redox-active molecules and their signaling functions during the expression of plant disease resistance.

    Science.gov (United States)

    Skelly, Michael J; Loake, Gary J

    2013-09-20

    Activation of immune responses in plants is associated with a parallel burst of both reactive oxygen intermediates (ROIs) and nitric oxide (NO). The mechanisms by which these small redox-active molecules are synthesized and their signaling functions are critical for plants to defend themselves against pathogen infection. The synthesis of apoplastic ROIs by plants after pathogen recognition has long been attributed to membrane-bound NAPDH oxidases. However, the emerging data suggest a role for other enzymes in various subcellular locations in ROI production after defense activation. It is becoming widely appreciated that NO exerts its biochemical function through the S-nitrosylation of reactive cysteine thiols on target proteins, constituting a key post-translational modification. Recent evidence suggests that S-nitrosylation of specific defense-related proteins regulates their activity. The source(s) of NO production after pathogen recognition remain(s) poorly understood. Some NO synthesis can be attributed to the activity of nitrate reductase but to date, no nitric oxide synthase (NOS) has been identified in higher plants. However, the signaling functions of S-nitrosylation are becoming more apparent and thus dissecting the molecular machinery underpinning this redox-based modification is vital to further our understanding of plant disease resistance. In addition to identifying new contributors to the oxidative burst, the discovery of an NOS in higher plants would significantly move the field forward. Since S-nitrosylation has now been confirmed to play various roles in immune signaling, this redox-based modification is a potential target to exploit for improving disease resistance in crop species.

  17. Recessive resistance to plant viruses.

    Science.gov (United States)

    Truniger, V; Aranda, M A

    2009-01-01

    About half of the approximately 200 known virus resistance genes in plants are recessively inherited, suggesting that this form of resistance is more common for viruses than for other plant pathogens. The use of such genes is therefore a very important tool in breeding programs to control plant diseases caused by pathogenic viruses. Over the last few years, the detailed analysis of many host/virus combinations has substantially advanced basic research on recessive resistance mechanisms in crop species. This type of resistance is preferentially expressed in protoplasts and inoculated leaves, influencing virus multiplication at the single-cell level as well as cell-to-cell movement. Importantly, a growing number of recessive resistance genes have been cloned from crop species, and further analysis has shown them all to encode translation initiation factors of the 4E (eIF4E) and 4G (eIF4G) families. However, not all of the loss-of-susceptibility mutants identified in collections of mutagenized hosts correspond to mutations in eIF4E and eIF4G. This, together with other supporting data, suggests that more extensive characterization of the natural variability of resistance genes may identify new host factors conferring recessive resistance. In this chapter, we discuss the recent work carried out to characterize loss-of-susceptibility and recessive resistance genes in crop and model species. We review actual and probable recessive resistance mechanisms, and bring the chapter to a close by summarizing the current state-of-the-art and offering perspectives on potential future developments.

  18. Structure-function analysis of the NB-ARC domain of plant disease resistance proteins.

    Science.gov (United States)

    van Ooijen, Gerben; Mayr, Gabriele; Kasiem, Mobien M A; Albrecht, Mario; Cornelissen, Ben J C; Takken, Frank L W

    2008-01-01

    Resistance (R) proteins in plants are involved in pathogen recognition and subsequent activation of innate immune responses. Most resistance proteins contain a central nucleotide-binding domain. This so-called NB-ARC domain consists of three subdomains: NB, ARC1, and ARC2. The NB-ARC domain is a functional ATPase domain, and its nucleotide-binding state is proposed to regulate activity of the R protein. A highly conserved methionine-histidine-aspartate (MHD) motif is present at the carboxy-terminus of ARC2. An extensive mutational analysis of the MHD motif in the R proteins I-2 and Mi-1 is reported. Several novel autoactivating mutations of the MHD invariant histidine and conserved aspartate were identified. The combination of MHD mutants with autoactivating hydrolysis mutants in the NB subdomain showed that the autoactivation phenotypes are not additive. This finding indicates an important regulatory role for the MHD motif in the control of R protein activity. To explain these observations, a three-dimensional model of the NB-ARC domain of I-2 was built, based on the APAF-1 template structure. The model was used to identify residues important for I-2 function. Substitution of the selected residues resulted in the expected distinct phenotypes. Based on the model, it is proposed that the MHD motif fulfils the same function as the sensor II motif found in AAA+ proteins (ATPases associated with diverse cellular activities)-co-ordination of the nucleotide and control of subdomain interactions. The presented 3D model provides a framework for the formulation of hypotheses on how mutations in the NB-ARC exert their effects.

  19. Disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs

    NARCIS (Netherlands)

    Denance, N.; Sanchez Vallet, A.; Goffner, D.; Molina, A.

    2013-01-01

    Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA), cytokini

  20. Disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs

    NARCIS (Netherlands)

    Denance, N.; Sanchez Vallet, A.; Goffner, D.; Molina, A.

    2013-01-01

    Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA), cytokini

  1. Antibody-mediated resistance against plant pathogens.

    Science.gov (United States)

    Safarnejad, Mohammad Reza; Jouzani, Gholamreza Salehi; Tabatabaei, Meisam; Tabatabaie, Meisam; Twyman, Richard M; Schillberg, Stefan

    2011-01-01

    Plant diseases have a significant impact on the yield and quality of crops. Many strategies have been developed to combat plant diseases, including the transfer of resistance genes to crops by conventional breeding. However, resistance genes can only be introgressed from sexually-compatible species, so breeders need alternative measures to introduce resistance traits from more distant sources. In this context, genetic engineering provides an opportunity to exploit diverse and novel forms of resistance, e.g. the use of recombinant antibodies targeting plant pathogens. Native antibodies, as a part of the vertebrate adaptive immune system, can bind to foreign antigens and eliminate them from the body. The ectopic expression of antibodies in plants can also interfere with pathogen activity to confer disease resistance. With sufficient knowledge of the pathogen life cycle, it is possible to counter any disease by designing expression constructs so that pathogen-specific antibodies accumulate at high levels in appropriate sub-cellular compartments. Although first developed to tackle plant viruses and still used predominantly for this purpose, antibodies have been targeted against a diverse range of pathogens as well as proteins involved in plant-pathogen interactions. Here we comprehensively review the development and implementation of antibody-mediated disease resistance in plants.

  2. Pathogen corruption and site-directed recombination at a plant disease resistance gene cluster

    Science.gov (United States)

    Nagy, Ervin D.; Bennetzen, Jeffrey L.

    2008-01-01

    The Pc locus of sorghum (Sorghum bicolor) determines dominant sensitivity to a host-selective toxin produced by the fungal pathogen Periconia circinata. The Pc region was cloned by a map-based approach and found to contain three tandemly repeated genes with the structures of nucleotide binding site–leucine-rich repeat (NBS–LRR) disease resistance genes. Thirteen independent Pc-to-pc mutations were analyzed, and each was found to remove all or part of the central gene of the threesome. Hence, this central gene is Pc. Most Pc-to-pc mutations were associated with unequal recombination. Eight recombination events were localized to different sites in a 560-bp region within the ∼3.7-kb NBS–LRR genes. Because any unequal recombination located within the flanking NBS–LRR genes would have removed Pc, the clustering of cross-over events within a 560-bp segment indicates that a site-directed recombination process exists that specifically targets unequal events to generate LRR diversity in NBS–LRR loci. PMID:18719093

  3. The reactive oxygen species network pathways: an essential prerequisite for perception of pathogen attack and the acquired disease resistance in plants

    Indian Academy of Sciences (India)

    Simeon O Kotchoni; Emma W Gachomo

    2006-09-01

    Availability of complete Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) genome sequences, together with molecular recourses of functional genomics and proteomics have revolutionized our understanding of reactive oxygen species (ROS) signalling network mediating disease resistance in plants. So far, ROS have been associated with aging, cellular and molecular alteration in animal and plant cells. Recently, concluding evidences suggest that ROS network is essential to induce disease resistance and even to mediate resistance to multiple stresses in plants. ROS are obligatory by-products emerging as a result of normal metabolic reactions. They have the potential to be both beneficial and harmful to cellular metabolism. Their dual effects on metabolic reactions are dosage specific. In this review we focus our attention on cellular ROS level to trigger beneficial effects on plant cells responding to pathogen attack. By exploring the research related contributions coupled with data of targeted gene disruption, and RNA interference approaches, we show here that ROS are ubiquitous molecules of redox-pathways that play a crucial role in plant defence mechanism. The molecular prerequisites of ROS network to activate plant defence system in response to pathogen infections are here underlined. Bioinformatic tools are now available to scientists for high throughput analysis of cellular metabolisms. These tools are used to illustrate crucial ROS-related genes that are involved in the defence mechanism of plants. The review describes also the emerging findings of ROS network pathways to modulate multiple stress resistance in plants.

  4. Plant defense gene promoter enhances the reliability of shiva-1 gene-induced resistance to soft rot disease in potato.

    Science.gov (United States)

    Yi, Jung Yoon; Seo, Hyo Won; Yang, Moon Sik; Robb, E Jane; Nazar, Ross N; Lee, Shin Woo

    2004-11-01

    PAL5, a tomato (Lycopersicon esculentum Mill.) plant defense gene that encodes phenylalanine ammonia-lyase, is known to respond to a variety of environmental stresses including pathogen infection and wounding. A shiva-1 gene recombinant that encodes a small synthetic antibacterial peptide under the PAL5 gene promoter was transformed into potato (Solanum tuberosum L.) and its ability to induce resistance to Erwinia carotovora was compared with a construct under the control of the constitutive and widely used cauliflower mosaic virus (CaMV) 35S promoter. The shiva-1 peptide, an analog of natural cecropin B, was shown previously to have high bactericidal activity in vitro, but when expressed in vivo under the control of the CaMV 35S promoter, the effects were very inconsistent. As observed previously, in the present studies a few transformants with the CaMV 35S promoter were highly resistant when assayed for susceptibility to soft rot disease. In marked contrast the majority of transformants with the PAL5 gene promoter were highly resistant. More-detailed analyses of the incorporated DNA indicated that most of the transformants with the CaMV 35S promoter contained multiple copies of the transforming DNA while all of the PAL5 recombinants contained single copies. The highly resistant CaMV 35S recombinant also was present as a single copy. The results indicate that, at least in this instance, a constitutive promoter may not be ideal for the effective expression of a foreign gene and suggest that multiple insertions may have negative consequences.

  5. Antibody-based resistance to plant pathogens.

    Science.gov (United States)

    Schillberg, S; Zimmermann, S; Zhang, M Y; Fischer, R

    2001-01-01

    Plant diseases are a major threat to the world food supply, as up to 15% of production is lost to pathogens. In the past, disease control and the generation of resistant plant lines protected against viral, bacterial or fungal pathogens, was achieved using conventional breeding based on crossings, mutant screenings and backcrossing. Many approaches in this field have failed or the resistance obtained has been rapidly broken by the pathogens. Recent advances in molecular biotechnology have made it possible to obtain and to modify genes that are useful for generating disease resistant crops. Several strategies, including expression of pathogen-derived sequences or anti-pathogenic agents, have been developed to engineer improved pathogen resistance in transgenic plants. Antibody-based resistance is a novel strategy for generating transgenic plants resistant to pathogens. Decades ago it was shown that polyclonal and monoclonal antibodies can neutralize viruses, bacteria and selected fungi. This approach has been improved recently by the development of recombinant antibodies (rAbs). Crop resistance can be engineered by the expression of pathogen-specific antibodies, antibody fragments or antibody fusion proteins. The advantages of this approach are that rAbs can be engineered against almost any target molecule, and it has been demonstrated that expression of functional pathogen-specific rAbs in plants confers effective pathogen protection. The efficacy of antibody-based resistance was first shown for plant viruses and its application to other plant pathogens is becoming more established. However, successful use of antibodies to generate plant pathogen resistance relies on appropriate target selection, careful antibody design, efficient antibody expression, stability and targeting to appropriate cellular compartments.

  6. Plant Diseases & Chemicals

    OpenAIRE

    Thompson, Sherm

    2008-01-01

    This course discusses the use of chemicals for plant disease control. Specifically, pesticides that can be used both in commercial or home/yard sitautions. This course also teaches how to determine plant diseases that may have caused a plant to die.

  7. Screening strawberry plants for anthracnose disease resistance using traditional and molecular techniques

    Science.gov (United States)

    Anthracnose is one of the most destructive diseases of strawberry which may cause fruit rot, leaf and petiole lesions, crown rot, wilt, and death. Crop loss due to anthracnose diseases can reach into the millions of dollars. Three species of Colletotrichum are considered causative agents of anthr...

  8. Exploiting pathogens' tricks of the trade for engineering of plant disease resistance : challenges and opportunities

    OpenAIRE

    Grant, Murray; Kazan, Kemal; Manners, John M.

    2013-01-01

    With expansion of our understanding of pathogen effector strategies and the multiplicity of their host targets, it is becoming evident that novel approaches to engineering broad-spectrum resistance need to be deployed. The increasing availability of high temporal gene expression data of a range of plant–microbe interactions enables the judicious choices of promoters to fine-tune timing and magnitude of expression under specified stress conditions. We can therefore contemplate engineering a ra...

  9. Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions

    Science.gov (United States)

    Basal stalk rot (BSR) and head rot (HR) caused by Sclerotinia sclerotiorum (Lib.) de Bary are traditionally major diseases of sunflower (Helianthus annuus L.) in the United States, while Phomopsis stem canker (PSC) caused by Phomopsis helianthi Munt.-Cvet. et. al. has increasingly become damaging in...

  10. Exogenous systemin has a contrasting effect on disease resistance in mycorrhizal tomato (Solanum lycopersicum) plants infected with necrotrophic or hemibiotrophic pathogens.

    Science.gov (United States)

    de la Noval, Blanca; Pérez, Eduardo; Martínez, Benedicto; León, Ondina; Martínez-Gallardo, Norma; Délano-Frier, John

    2007-07-01

    A study was performed to determine the effect of the systemin polypeptide on the bio-protective effect of arbuscular mycorrhizal fungi (AMF) in tomato plants infected with Alternaria solani, Phytophthora infestans or P. parasitica. Before infection, tomato plants were colonized with two different AMF, Glomus fasciculatum or G. clarum. In addition, a group of inoculated plants was treated with systemin, just after emergence. The exogenous application of systemin marginally suppressed the resistance against A. solani leaf blight observed in G. fasciculatum mycorrhizal plants but significantly enhanced it in plants colonized with G. clarum. Systemin induced resistance to P. parasitica in leaves of G. fasciculatum mycorrhizal plants, in which AMF colonization alone was shown to have no protective effect. Conversely, none of the treatments led to resistance to root or stem rots caused by P. infestans or P. parasitica. The above effects did not correlate with changes in the activity levels of beta-1,3-glucanase (BG), chitinase (CHI), peroxidase (PRX), and phenylalanine ammonium lyase (PAL) in leaves of infected plants. However, they corroborated previous reports showing that colonization by AMF can lead to a systemic resistance response against A. solani. Systemic resistance to A. solani was similarly observed in non-mycorrhizal systemin-treated plants, which, in contrast, showed increased susceptibility to P. infestans and P. parasitica. The results indicated that the pattern of systemic disease resistance conferred by mycorrhizal colonization was dependent on the AMF employed and could be altered by the exogenous application of systemin, by means of a still undefined mechanism.

  11. Expression of a novel antimicrobial peptide Penaeidin4-1 in creeping bentgrass (Agrostis stolonifera L. enhances plant fungal disease resistance.

    Directory of Open Access Journals (Sweden)

    Man Zhou

    Full Text Available BACKGROUND: Turfgrass species are agriculturally and economically important perennial crops. Turfgrass species are highly susceptible to a wide range of fungal pathogens. Dollar spot and brown patch, two important diseases caused by fungal pathogens Sclerotinia homoecarpa and Rhizoctonia solani, respectively, are among the most severe turfgrass diseases. Currently, turf fungal disease control mainly relies on fungicide treatments, which raises many concerns for human health and the environment. Antimicrobial peptides found in various organisms play an important role in innate immune response. METHODOLOGY/PRINCIPAL FINDINGS: The antimicrobial peptide - Penaeidin4-1 (Pen4-1 from the shrimp, Litopenaeus setiferus has been reported to possess in vitro antifungal and antibacterial activities against various economically important fungal and bacterial pathogens. In this study, we have studied the feasibility of using this novel peptide for engineering enhanced disease resistance into creeping bentgrass plants (Agrostis stolonifera L., cv. Penn A-4. Two DNA constructs were prepared containing either the coding sequence of a single peptide, Pen4-1 or the DNA sequence coding for the transit signal peptide of the secreted tobacco AP24 protein translationally fused to the Pen4-1 coding sequence. A maize ubiquitin promoter was used in both constructs to drive gene expression. Transgenic turfgrass plants containing different DNA constructs were generated by Agrobacterium-mediated transformation and analyzed for transgene insertion and expression. In replicated in vitro and in vivo experiments under controlled environments, transgenic plants exhibited significantly enhanced resistance to dollar spot and brown patch, the two major fungal diseases in turfgrass. The targeting of Pen4-1 to endoplasmic reticulum by the transit peptide of AP24 protein did not significantly impact disease resistance in transgenic plants. CONCLUSION/SIGNIFICANCE: Our results

  12. The Effector SPRYSEC-19 of Globodera rostochiensis Suppresses CC-NB-LRR-Mediated Disease Resistance in Plants

    NARCIS (Netherlands)

    Postma, W.J.; Slootweg, E.J.; Rehman, S.; Finkers-Tomczak, A.M.; Tytgat, T.O.G.; Gelderen, van K.; Lozano Torres, J.L.; Roosien, J.; Pomp, H.; Schaik, van C.C.; Bakker, J.; Goverse, A.; Smant, G.

    2012-01-01

    The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance

  13. Purification of novel protein elicitor from Botrytis cinerea that induces disease resistance and drought tolerance in plants.

    Science.gov (United States)

    Zhang, Yunhua; Yang, Xiufen; Liu, Quan; Qiu, Dewen; Zhang, Yuliang; Zeng, Hongmei; Yuan, Jingjing; Mao, Jianjun

    2010-02-28

    PebC1, a novel protein elicitor was isolated and purified from the mycelium of gray mold fungus, Botrytis cinerea strain BC-4-2-2-1. The protein was eluted through HiTrap DEAE FF and RESOURCE Q anion exchange chromatography and displayed as a single band with an apparent molecular weight of 36 kDa on silver staining sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The pI of the purified protein PebC1 was determined by 2-DE and was 4.85. Three peptide segments were obtained by MALDI-TOF. Similarity, the homology matching using protein BLAST search found that two proteins, viz. XP_001593856 and XP_001551609 were having high score and covered sequence of the three peptides. Protein XP_001551609, a deduced protein nascent polypeptide-associated complex alpha-polypeptide, was more authentic because it was from Botryotinia fuckeliana that is better known as its anamorph, B.cinerea and showed 95% homology with the three polypeptides. The full cDNA sequence encoding for pebC1 (Genbank accession number FJ748868) was amplified from B. cinerea and consists of 639bp, which is same as a registered gene of XM_001551559, a nascent polypeptide-associated complex alpha-polypeptide partial mRNA. The gene encode a hypothetical protein speculated from an annotated genomic sequence from B. fuckeliana B05.10 (NW_001814507) and there is no publication about the gene. The PebC1 protein significantly promoted wheat seedling growth with an optimum protein concentration of 5 microg/mL. Root systemic activity of wheat with 4-5 leaves increased by 1.29 fold, and the wheat seedling drought resistance integrated index increased from 36.53 to 57.08 under two cycles of drought stress after treatment of PebC1. PebC1 protein at the optimum concentration of 10 microg/mL induced 69.19% disease resistance against gray mold fungus in tomato. Furthermore, phenylalanine ammonia-lyase (PAL), peroxides (POD), and polyphenol oxidase (PPO) related to plant resistance metabolism were also

  14. The Genetic and Molecular Basis of Plant Resistance to Pathogens

    Institute of Scientific and Technical Information of China (English)

    Yan Zhang; Thomas Lubberstedt; Mingliang Xu

    2013-01-01

    Plant pathogens have evolved numerous strategies to obtain nutritive materials from their host,and plants in turn have evolved the preformed physical and chemical barriers as well as sophisticated two-tiered immune system to combat pathogen attacks.Genetically,plant resistance to pathogens can be divided into qualitative and quantitative disease resistance,conditioned by major gene(s) and multiple genes with minor effects,respectively.Qualitative disease resistance has been mostly detected in plant defense against biotrophic pathogens,whereas quantitative disease resistance is involved in defense response to all plant pathogens,from biotrophs,hemibiotrophs to necrotrophs.Plant resistance is achieved through interception of pathogen-derived effectors and elicitation of defense response.In recent years,great progress has been made related to the molecular basis underlying host-pathogen interactions.In this review,we would like to provide an update on genetic and molecular aspects of plant resistance to pathogens.

  15. Plant pathogen resistance

    Science.gov (United States)

    Greenberg, Jean T; Jung, Ho Won; Tschaplinski, Timothy

    2012-11-27

    Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

  16. Plant pathogen resistance

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Jean T.; Jung, Ho Won; Tschaplinski, Timothy

    2015-10-20

    Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

  17. Dominant resistance against plant viruses

    NARCIS (Netherlands)

    Ronde, de D.; Butterbach, P.B.E.; Kormelink, R.J.M.

    2014-01-01

    To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified agains

  18. Powdery Mildew Disease Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Somerville, Shauna C.

    2010-08-31

    The overall goal of this project was to characterize the PMR5 protein, a member of the DUF231/TBR family, and to determine its role in plant cell wall biogenesis. Since the pmr5 mutants are also resistant to the fungal powdery mildew pathogen, we wished to determine what specific cell wall changes are associated with disease resistance and why. The graduate student working on this project made mutations in the putative active site of PMR5, assuming it is a member of the SGNH/GDSL esterase superfamily (Anantharaman and Aravind, 2010, Biology Direct 5, 1). These mutants were inactive in planta suggesting that PMR5 is a functional enzyme and not a binding protein or chaperone. In addition, she determined that cell wall preparations from the pmr5 mutant exhibited a modest reduction (13%) in total acetyl groups. To pursue characterization further, the graduate student expressed the PMR5 protein in a heterologous E. coli system. She could purify PMR5 using a two step protocol based on tags added to the N and C terminus of the protein. She was able to show the PMR5 protein bound to pectins, including homogalacturonan, but not to other cell wall components (e.g., xyloglucans, arabinans). Based on these observations, a postdoctoral fellow is currently developing an enzyme assay for PMR5 based on the idea that it may be acetylating the homogalacturonic acid pectin fraction. Our initial experiments to localize PMR5 subcellularly suggested that it occurred in the endoplasmic reticulum. However, since the various pectins are believed to be synthesized in the Golgi apparatus, we felt it necessary to repeat our results using a native promoter expression system. Within the past year, we have demonstrated conclusively that PMR5 is localized to the endoplasmic reticulum, a location that sets it apart from most cell wall biogenesis and modification enzymes. The graduate student contributed to the characterization of two suppressor mutants, which were selected as restoring powdery

  19. Plant disease resistance genes encode members of an ancient and diverse protein family within the nucleotide-binding superfamily.

    Science.gov (United States)

    Meyers, B C; Dickerman, A W; Michelmore, R W; Sivaramakrishnan, S; Sobral, B W; Young, N D

    1999-11-01

    The nucleotide binding site (NBS) is a characteristic domain of many plant resistance gene products. An increasing number of NBS-encoding sequences are being identified through gene cloning, PCR amplification with degenerate primers, and genome sequencing projects. The NBS domain was analyzed from 14 known plant resistance genes and more than 400 homologs, representing 26 genera of monocotyledonous, dicotyle-donous and one coniferous species. Two distinct groups of diverse sequences were identified, indicating divergence during evolution and an ancient origin for these sequences. One group was comprised of sequences encoding an N-terminal domain with Toll/Interleukin-1 receptor homology (TIR), including the known resistance genes, N, M, L6, RPP1 and RPP5. Surprisingly, this group was entirely absent from monocot species in searches of both random genomic sequences and large collections of ESTs. A second group contained monocot and dicot sequences, including the known resistance genes, RPS2, RPM1, I2, Mi, Dm3, Pi-B, Xa1, RPP8, RPS5 and Prf. Amino acid signatures in the conserved motifs comprising the NBS domain clearly distinguished these two groups. The Arabidopsis genome is estimated to contain approximately 200 genes that encode related NBS motifs; TIR sequences were more abundant and outnumber non-TIR sequences threefold. The Arabidopsis NBS sequences currently in the databases are located in approximately 21 genomic clusters and 14 isolated loci. NBS-encoding sequences may be more prevalent in rice. The wide distribution of these sequences in the plant kingdom and their prevalence in the Arabidopsis and rice genomes indicate that they are ancient, diverse and common in plants. Sequence inferences suggest that these genes encode a novel class of nucleotide-binding proteins.

  20. Inducing Fungus-Resistance into Plants through Biotechnology

    OpenAIRE

    Wani, Shabir Hussain

    2010-01-01

    Plant diseases are caused by a variety of plant pathogens including fungi, and their management requires the use of techniques like transgenic technology, molecular biology, and genetics. There have been attempts to use gene technology as an alternative method to protect plants from microbial diseases, in addition to the development of novel agrochemicals and the conventional breeding of resistant cultivars. Various genes have been introduced into plants, and the enhanced resistance against f...

  1. Enhanced disease resistance to Botrytis cinerea in myb46 Arabidopsis plants is associated to an early down-regulation of CesA genes.

    Science.gov (United States)

    Ramírez, Vicente; García-Andrade, Javier; Vera, Pablo

    2011-06-01

    The cell wall is a protective barrier of paramount importance for the survival of plant cells. Monitoring the integrity of cell wall allows plants to quickly activate defence pathways to minimize pathogen entry and reduce the spread of disease. Counterintuitively, however, pharmacological effects as well as genetic lesions that affect cellulose biosynthesis and content confer plants with enhanced resistance against necrotrophic fungi. This kind of pathogens target cellulose for degradation to facilitate penetration and to generate glucose units as a food source. Our results points towards the existence of a transcriptional reprogramming mechanism in genes encoding cellulose synthases (CesAs) that occurs very soon after Botrytis cinerea attack and that results in a temporarily shut down of some CesA genes. Interestingly, the observed coordinated down-regulation of CesA genes is more pronounced, and occurs earlier, in myb46 mutant plants. In the resistant myb46 plants, pathogen infection induces transient down-regulation of CesA genes that concurs with a selective transcriptional reprogramming in a set of genes encoding structural cell wall proteins and extracellular remodelling enzymes. Together with previous indications, our results favour the hypothesis that CesAs are part of a surveillance system of the cell wall integrity that senses the presence of a pathogen and transduces that signal into a rapid transcriptional reprogramming of the affected cell.

  2. Activity against drug resistant-tuberculosis strains of plants used in Mexican traditional medicine to treat tuberculosis and other respiratory diseases.

    Science.gov (United States)

    Camacho-Corona, María Del Rayo; Ramírez-Cabrera, Mónica A; Santiago, Omar González-; Garza-González, Elvira; Palacios, Isidoro de Paz; Luna-Herrera, Julieta

    2008-01-01

    Tuberculosis (TB) kills about 3 million people per year worldwide. Furthermore, TB is an infectious disease associated with HIV patients, and there is a rise in multidrug-resistant TB (MDR-TB) cases around the world. There is a need for new anti-TB agents. The study evaluated the antimycobacterial activity of nine plants used in Mexican traditional medicine to treat tuberculosis and other respiratory diseases. Nasturtium officinale showed the best activity (MIC = 100 microg/mL) against the sensitive Mycobacterium tuberculosis. The following plants were active also but at 200 microg/mL: Citrus sinensis, Citrus aurantifolia, Foeniculum vulgare, Larrea tridentata, Musa acuminata and Olea europaea. Contrary to the above data, activity against drug-resistant variants of M. tuberculosis was more evident, e.g. N. officinale was the most potent (MIC aurantifolia, C. sinensis and O. europaea (MIC = 25 microg/mL). These data point to the importance of biological testing of extracts against drug-resistant M. tuberculosis isolates, and the bioguided assay of these extracts for the identification of lead compounds against MDR-TB isolates. Copyright (c) 2007 John Wiley & Sons, Ltd.

  3. Role of Salicylic Acid in Plant Disease Resistance%水杨酸在植物抗病中的作用

    Institute of Scientific and Technical Information of China (English)

    丁秀英; 苏宝林; 张军; 徐惠风

    2001-01-01

    Salicylic acid is an important endogenous signal molecule in the activation of plant defense responses. The basic properties and the function of salicylic acid involved in plant disease resistance are introduced. The operation mechanisms of salicylic acid inducing plant disease resistance have been discussed in the interaction of salicylic acid with salicylic acid-binding protein and salicylic acid-dependent signalling pathway with salicylic acid-independent signalling pathway. Finally, significance of the study on mechanisms of salicylic acid action are summarized.%水杨酸是一种重要的能激活植物抗病防卫反应的内源信号分子。本文首先介绍了水杨酸的基本性质及水杨酸在植物抗病中的作用,然后从水杨酸与水杨酸结合蛋白的相互作用以及水杨酸介导的信号传导途径与非水杨酸介导的信号途径等方面初步探讨了水杨酸诱导植物抗病性的作用机制,最后总结了研究水杨酸作用机制对植物抗性生理和抗性分子生物学发展的意义。

  4. 植物抗病机制的研究进展%Research Progress on the Mechanism of Plant Disease Resistance

    Institute of Scientific and Technical Information of China (English)

    杨银; 高志勇

    2016-01-01

    植物在发育过程中会面临多种病原菌的侵染,在长期的进化中,植物演化出了两道免疫防线来抑制病原菌的破坏。第一道防线是病原相关分子模式所触发的免疫反应(PAMP-Triggered Immunity,PTI),第二道防线是效应因子触发的免疫反应(Effector-Triggered-Immunity,ETI)。在ETI过程中,植物抗病基因编码的抗病蛋白具有保守的核苷酸结合位点(nucleotide binding site,NBS)以及富含亮氨酸重复序列(Leucine rich repeat ,LRR),它能够直接或者间接的识别病原菌释放的效应因子,引起效应因子触发的免疫反应,引起植物细胞的主动死亡,即超敏反应(Hypersensitive response,HR),进而抑制病原菌的侵染。通过基因组分析,拟南芥中大约有125个植物抗病基因,但是只有RPM1与RPS2等少数抗病基因的功能得到报道,并且对于植物抗病信号途径的研究也不是很清楚。这是因为传统的遗传学分析方法去研究植物抗病基因的功能存在局限性,造成这种局限性的主要原因是因为植物抗病基因的功能冗余以及参与植物抗病信号转导通过的上下游基因缺失致死。笔者综述了近年来关于植物抗病机制的研究进展,并介绍了该领域主要存在的问题。%Plants in the development process will be faced with a variety of pathogen infection, in the long term evolution, the plant evolution of the two line of defense to inhibit the destruction of pathogenic bacteria. The first line of defense is the immune response (Immunity PAMP-Triggered, PTI) triggered by pathogen associated molecular patterns, and the second line of defense is the immune response (Effector-Triggered-Immunity, ETI) triggered by effector factors. In the ETI, plant disease resistance genes encoding resis-tance proteins with conserved nucleotide binding site (nucleotide binding site, NBS) and leucine rich repeats (leucine rich repeat LRR

  5. Engineering disease resistant cattle.

    Science.gov (United States)

    Donovan, David M; Kerr, David E; Wall, Robert J

    2005-10-01

    Mastitis is a disease of the mammary gland caused by pathogens that find their way into the lumen of the gland through the teat canal. Mammary gland infections cost the US dairy industry approximately $2 billion dollars annually and have a similar impact in Europe. In the absence of effective treatments or breeding strategies to enhance mastitis resistance, we have created transgenic dairy cows that express lysostaphin in their mammary epithelium and secrete the antimicrobial peptide into milk. Staphylococcus aureus, a major mastitis pathogen, is exquisitely sensitive to lysostaphin. The transgenic cattle resist S. aureus mammary gland challenges, and their milk kills the bacteria, in a dose dependent manner. This first step in protecting cattle against mastitis will be followed by introduction of other genes to deal with potential resistance issues and other mastitis causing organisms. Care will be taken to avoid altering milk's nutritional and manufacturing properties. Multi-cistronic constructs may be required to achieve our goals as will other strategies possibly involving RNAi and gene targeting technology. This work demonstrates the possibility of using transgenic technology to address disease problems in agriculturally important species.

  6. Heterologous expression of the glucose oxidase gene in Trichoderma atroviride leads enhanced ability to attack phytopathogenic fungi and induction of plant systemic disease resistance

    Institute of Scientific and Technical Information of China (English)

    Robert L Mach; Brunner Kurt; Matteo Lorito; Susanne Zeilinger; Rosalia Ciliento; Sheridan Woo

    2004-01-01

    @@ A transgenic strain of Trichoderma atroviride that expresses the Aspergillus niger glucose oxidase gene goxA under a homologous pathogen-inducible promoter (nag1) has been constructed, with the aim of increasing the ability of this biocontrol agent (BCA) to attack phytopathogenic fungi and enhance plant systemic disease resistance. The sporulation and growth rate of the transgenic progenies were similar to the wild-type strain Pl. goxA expression occurred immediately after contact with the plant pathogen,and the glucose oxidase formed was secreted extracellularly. The transformed strain SJ3 4, containing 12-14 copies of the transgene, produced significantly less N-acetyl-glucosaminidase and endochitinase then wild type. However, the ability of its culture filtrate to inhibit the germination of Botrytis cinerea spores was increased by about 3-fold. In comparison to P1, the transgenic strain more quickly overgrew and lysed in vitro the pathogens Rhizoctonia solani and Pythium ultimum.

  7. Advances in the Research of Molecudar Mechanism and Geaetic Engineering for Plant Disease Resistance%植物抗病分子机制及抗病基因工程研究进展

    Institute of Scientific and Technical Information of China (English)

    张艳贞; 魏松红; 杜娟; 王罡

    2000-01-01

    At the point of genetic basis of plant-microbe interactions, the research advances on the molecular mechanism of plant disease resistance, and the genetic engineering for plant resistance to viral, fungal, aeterial and nemotode diseases were discussed.%本文从植物与病原物互作的遗传基础角度讨论了植物抗病分子机制以及植物抗病毒、真菌、细菌和线虫病基因工程的主 要研究进展,并对有关进展作了简单评析。

  8. Combating plant diseases--the Darwin connection.

    Science.gov (United States)

    Hollomon, Derek W; Brent, Keith J

    2009-11-01

    Although Darwin knew of plant diseases, he did not study them as part of his analysis of natural selection. Effective plant disease control has only been developed after his death. This article explores the relevance of Darwin's ideas to three problem areas with respect to diseases caused by fungi: emergence of new diseases, loss of disease resistance bred into plants and development of fungicide resistance. Darwin's concept of change through natural or artificial selection relied on selection of many small changes, but subsequent genetic research has shown that change can also occur through large steps. Appearance of new diseases can involve gene duplication, transfer or recombination, but all evidence points to both host plant resistance and fungicide susceptibility being overcome through point mutations. Because the population size of diseases such as rusts and powdery and downy mildews is so large, all possible point mutations are likely to occur daily, even during moderate epidemics. Overcoming control measures therefore reflects the overall fitness of these mutants, and much resource effort is being directed towards assessment of their fitness, both in the presence and in the absence of selection. While recent developments in comparative genomics have caused some revision of Darwin's ideas, experience in managing plant disease control measures clearly demonstrates the relevance of concepts he introduced 150 years ago. It also reveals the remarkable speed and the practical impact of adaptation in wild microorganism populations to changes in their environment, and the difficulty of stopping or delaying such adaptation.

  9. Application of next-generation sequencing for rapid marker development in molecular plant breeding: a case study on anthracnose disease resistance in Lupinus angustifolius L.

    Directory of Open Access Journals (Sweden)

    Yang Huaan

    2012-07-01

    Full Text Available Abstract Background In the last 30 years, a number of DNA fingerprinting methods such as RFLP, RAPD, AFLP, SSR, DArT, have been extensively used in marker development for molecular plant breeding. However, it remains a daunting task to identify highly polymorphic and closely linked molecular markers for a target trait for molecular marker-assisted selection. The next-generation sequencing (NGS technology is far more powerful than any existing generic DNA fingerprinting methods in generating DNA markers. In this study, we employed a grain legume crop Lupinus angustifolius (lupin as a test case, and examined the utility of an NGS-based method of RAD (restriction-site associated DNA sequencing as DNA fingerprinting for rapid, cost-effective marker development tagging a disease resistance gene for molecular breeding. Results Twenty informative plants from a cross of RxS (disease resistant x susceptible in lupin were subjected to RAD single-end sequencing by multiplex identifiers. The entire RAD sequencing products were resolved in two lanes of the 16-lanes per run sequencing platform Solexa HiSeq2000. A total of 185 million raw reads, approximately 17 Gb of sequencing data, were collected. Sequence comparison among the 20 test plants discovered 8207 SNP markers. Filtration of DNA sequencing data with marker identification parameters resulted in the discovery of 38 molecular markers linked to the disease resistance gene Lanr1. Five randomly selected markers were converted into cost-effective, simple PCR-based markers. Linkage analysis using marker genotyping data and disease resistance phenotyping data on a F8 population consisting of 186 individual plants confirmed that all these five markers were linked to the R gene. Two of these newly developed sequence-specific PCR markers, AnSeq3 and AnSeq4, flanked the target R gene at a genetic distance of 0.9 centiMorgan (cM, and are now replacing the markers previously developed by a traditional DNA

  10. Application of next-generation sequencing for rapid marker development in molecular plant breeding: a case study on anthracnose disease resistance in Lupinus angustifolius L.

    Science.gov (United States)

    Yang, Huaan; Tao, Ye; Zheng, Zequn; Li, Chengdao; Sweetingham, Mark W; Howieson, John G

    2012-07-17

    In the last 30 years, a number of DNA fingerprinting methods such as RFLP, RAPD, AFLP, SSR, DArT, have been extensively used in marker development for molecular plant breeding. However, it remains a daunting task to identify highly polymorphic and closely linked molecular markers for a target trait for molecular marker-assisted selection. The next-generation sequencing (NGS) technology is far more powerful than any existing generic DNA fingerprinting methods in generating DNA markers. In this study, we employed a grain legume crop Lupinus angustifolius (lupin) as a test case, and examined the utility of an NGS-based method of RAD (restriction-site associated DNA) sequencing as DNA fingerprinting for rapid, cost-effective marker development tagging a disease resistance gene for molecular breeding. Twenty informative plants from a cross of RxS (disease resistant x susceptible) in lupin were subjected to RAD single-end sequencing by multiplex identifiers. The entire RAD sequencing products were resolved in two lanes of the 16-lanes per run sequencing platform Solexa HiSeq2000. A total of 185 million raw reads, approximately 17 Gb of sequencing data, were collected. Sequence comparison among the 20 test plants discovered 8207 SNP markers. Filtration of DNA sequencing data with marker identification parameters resulted in the discovery of 38 molecular markers linked to the disease resistance gene Lanr1. Five randomly selected markers were converted into cost-effective, simple PCR-based markers. Linkage analysis using marker genotyping data and disease resistance phenotyping data on a F8 population consisting of 186 individual plants confirmed that all these five markers were linked to the R gene. Two of these newly developed sequence-specific PCR markers, AnSeq3 and AnSeq4, flanked the target R gene at a genetic distance of 0.9 centiMorgan (cM), and are now replacing the markers previously developed by a traditional DNA fingerprinting method for marker

  11. Application of plant impedance for diagnosing plant disease

    Science.gov (United States)

    Xu, Huirong; Jiang, Xuesong; Zhu, Shengpan; Ying, Yibin

    2006-10-01

    Biological cells have components acting as electrical elements that maintain the health of the cell by regulation of the electrical charge content. Plant impedance is decided by the state of plant physiology and pathology. Plant physiology and pathology can be studies by measuring plant impedance. The effect of Cucumber Mosaic Virus red bean isolate (CMV-RB) on electrical resistance of tomato leaves was studied by the method of impedance measurement. It was found that the value of resistance of tomato leaves infected with CMV-RB was smaller than that in sound plant leaves. This decrease of impedances in leaf tissue was occurred with increased severity of disease. The decrease of resistance of tomato leaves infected with CMV-RB could be detected by electrical resistance detecting within 4 days after inoculation even though significant visible differences between the control and the infected plants were not noted, so that the technique for measurement of tomato leaf tissue impedance is a rapid, clever, simple method on diagnosis of plant disease.

  12. Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

    NARCIS (Netherlands)

    Stulemeijer, I.J.E.

    2008-01-01

    Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the extracell

  13. Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

    NARCIS (Netherlands)

    Stulemeijer, I.J.E.

    2008-01-01

    Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the

  14. Phosphorylation and proteome dynamics in pathogen-resistant tomato plants

    NARCIS (Netherlands)

    Stulemeijer, I.J.E.

    2008-01-01

    Microbial plant pathogens impose a continuous threat on global food production. Similar to disease resistance in mammals, an innate immune system allows plants to recognise pathogens and swiftly activate defence. For the work described in this thesis, the interaction between tomato and the extracell

  15. Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

    Directory of Open Access Journals (Sweden)

    Masayoshi Hashimoto

    2016-10-01

    Full Text Available The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species.

  16. Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

    Science.gov (United States)

    Hashimoto, Masayoshi; Neriya, Yutaro; Yamaji, Yasuyuki; Namba, Shigetou

    2016-01-01

    The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF) 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species. PMID:27833593

  17. Disease resistance in sugarcane – An overview

    Directory of Open Access Journals (Sweden)

    A. Ramesh Sundar

    2015-12-01

    Full Text Available Sugarcane is one of the important commercial crops cultivated world-wide both under tropical and sub-tropical conditions. The crop gains economic importance by virtue of its industrial potential in terms of products like crystal white sugar, bagasse, pressmud, power etc. Among the various production constraints of the crop, diseases are seen as a major threat for sustaining the productivity of sugarcane. Conventional Breeding is a lengthy process and it involves almost more than 10 years for the release of a commercial variety. Many varieties with superior agronomical traits have succumbed to diseases like red rot and smut during the course of cultivation, which hitherto at the time of release were rated to be resistant. The breakdown of disease resistance is attributed to the possible emergence of new virulent pathotypes. This situation has warranted a pertinent need to have a thorough understanding on inheritance pattern and mechanism of disease resistance in sugarcane, which would aid for quick screening of disease resistant clones and successful management of the diseases, respectively. Overall, there is a paradigm shift in the understanding of plant disease resistance, thanks to the advent of robust molecular tools. An integration of the tools of “Omics” namely genomics, proteomics, metabolomics etc. has further strengthened in deciphering plant-pathogen interactions at the molecular level. With the accomplishments in elucidating sugarcane ESTs, which was ably supported by employing the next generation sequencing platforms to unlock the secrets of pathogenomics in sugarcane, it is now made possible to further improve our understanding on disease resistance in sugarcane. Giving the scenario, the future looks evenmore promising, wherein convincing results are in the offing to thoroughly unravel the enigmatic relationship between sugarcane and its important pathogens.

  18. Overexpression of a modified plant thionin enhances disease resistance to citrus canker and huanglongbing (HLB, citrus greening)

    Science.gov (United States)

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the United States citrus industry. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized e...

  19. Disease cycle approach to plant disease prediction.

    Science.gov (United States)

    De Wolf, Erick D; Isard, Scott A

    2007-01-01

    Plant disease cycles represent pathogen biology as a series of interconnected stages of development including dormancy, reproduction, dispersal, and pathogenesis. The progression through these stages is determined by a continuous sequence of interactions among host, pathogen, and environment. The stages of the disease cycle form the basis of many plant disease prediction models. The relationship of temperature and moisture to disease development and pathogen reproduction serve as the basis for most contemporary plant disease prediction systems. Pathogen dormancy and inoculum dispersal are considered less frequently. We found extensive research efforts evaluating the performance of prediction models as part of operation disease management systems. These efforts appear to be greater than just a few decades ago, and include novel applications of Bayesian decision theory. Advances in information technology have stimulated innovations in model application. This trend must accelerate to provide the disease management strategies needed to maintain global food supplies.

  20. Transposon tagging of disease resistance genes

    Energy Technology Data Exchange (ETDEWEB)

    Michelmore, R.W. (California Univ., Davis, CA (USA). Dept. of Physics)

    1989-01-01

    We are developing a transposon mutagenesis system for lettuce to clone genes for resistance to the fungal pathogen, Bremia lactucae. Activity of heterologous transposons is being studied in transgenic plants. Southern analysis of T{sub 1} and T{sub 2} plants containing Tam3 from Antirrhinum provided ambiguous results. Multiple endonuclease digests indicated that transposition had occurred; however, in no plant were all endonuclease digests consistent with a simple excision event. Southern or PCR analysis of over 50 plans containing Ac from maize have also failed to reveal clear evidence of transposition; this is contrast to experiments by others with the same constructs who have observed high rates of Ac excision in other plant species. Nearly all of 65 T{sub 2} families containing Ac interrupting a chimeric streptomycin resistance gene (Courtesy J. Jones, Sainsbury Lab., UK) clearly segregated for streptomycin resistance. Southern analyses, however, showed no evidence of transposition, indicating restoration of a functional message by other mechanisms, possibly mRNA processing. Transgenic plants have also been generated containing CaMV 35S or hsp70 promoters fused to transposase coding sequences or a Ds element interrupting a chimeric GUS gene (Courtesy M. Lassner, UC Davis). F{sub 1} plants containing both constructs were analyzed for transposition. Only two plants containing both constructs were obtained from 48 progeny, far fewer than expected, and neither showed evidence of transposition in Southerns and GUS assays. We are currently constructing further chimeric transposase fusions. To test for the stability of the targeted disease resistance genes, 50,000 F{sub 1} plants heterozygous for three resistance genes were generated; no mutants have been identified in the 5000 so far screened.

  1. Plant resistance within the Rutaceae to Asian citrus psyllid

    Science.gov (United States)

    USDA-ARS recently initiated research on host plant resistance to the Asian citrus psyllid. The psyllid is an important invasive pest of citrus in the United States because it transmits a serious disease of citrus known as huanglongbing (citrus greening). There is no cure for this bacterial disease. ...

  2. Strategies for antiviral resistance in transgenic plants

    NARCIS (Netherlands)

    Prins, M.W.; Laimer, M.; Noris, E.; Schubert, J.; Wassenegger, M.; Tepfer, M.

    2008-01-01

    Genetic engineering offers a means of incorporating new virus resistance traits into existing desirable plant cultivars. The initial attempts to create transgenes conferring virus resistance were based on the pathogen-derived resistance concept. The expression of the viral coat protein gene in

  3. RNA silencing and plant viral diseases.

    Science.gov (United States)

    Wang, Ming-Bo; Masuta, Chikara; Smith, Neil A; Shimura, Hanako

    2012-10-01

    RNA silencing plays a critical role in plant resistance against viruses, with multiple silencing factors participating in antiviral defense. Both RNA and DNA viruses are targeted by the small RNA-directed RNA degradation pathway, with DNA viruses being also targeted by RNA-directed DNA methylation. To evade RNA silencing, plant viruses have evolved a variety of counter-defense mechanisms such as expressing RNA-silencing suppressors or adopting silencing-resistant RNA structures. This constant defense-counter defense arms race is likely to have played a major role in defining viral host specificity and in shaping viral and possibly host genomes. Recent studies have provided evidence that RNA silencing also plays a direct role in viral disease induction in plants, with viral RNA-silencing suppressors and viral siRNAs as potentially the dominant players in viral pathogenicity. However, questions remain as to whether RNA silencing is the principal mediator of viral pathogenicity or if other RNA-silencing-independent mechanisms also account for viral disease induction. RNA silencing has been exploited as a powerful tool for engineering virus resistance in plants as well as in animals. Further understanding of the role of RNA silencing in plant-virus interactions and viral symptom induction is likely to result in novel anti-viral strategies in both plants and animals.

  4. Purification and characterization of alkaline pectin lyase from a newly isolated Bacillus clausii and its application in elicitation of plant disease resistance.

    Science.gov (United States)

    Li, Zuming; Bai, Zhihui; Zhang, Baoguo; Li, Baojv; Jin, Bo; Zhang, Michael; Lin, Francis; Zhang, Hongxun

    2012-08-01

    Alkaline pectin lyase (PNL) shows potential as a biological control agent against several plant diseases. We isolated and characterized a new Bacillus clausii strain that can produce 4,180 U/g of PNL using sugar beet pulp as a carbon source and inducer. The PNL was purified to apparent homogeneity using ultrafiltration, ammonium sulfate fractionation, DEAE Sepharose Fast Flow, and Sephadex G-75 gel filtration. The purified PNL was found to be a monomeric protein with a molecular weight of 35 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). It demonstrated optimal activity with K(m) of 0.87 mg/ml at pH 10.0 and 60 °C. The enzyme is stable in the pH range of 8.0-10.0 and temperature ≤40 °C. Ca(2+) was found to stimulate the enzymatic activity of the PNL by up to 410 %. Mass spectrometric results gave 38 % match coverage with pectate lyase from B. clausii KSM-K16 (gi|56961845). The PNL was found to elicit disease resistance in cucumber seedlings, suggesting that it may have applications in biocontrol and sustainable agriculture.

  5. Application and Research Development of Ectomycorrhizae on Forest Disease Resistance

    Institute of Scientific and Technical Information of China (English)

    WANGYuan; JIAXiuzhen; LIANGJun; ZHANGXingyao

    2004-01-01

    Ectomycorrhizae (ECM) is becoming the research hotspot because it can improve plant nutrient cycling and storage and strengthen plant resistance to adversity and disease. It is well known that ECM can enhance plant resistance to soil-borne and stem diseases. The mechanisms mainly include: plant tender roots will be protected well by sheath; ECM can facilitate uptake and transport capacity of nutrition and water to roots and increase plants vigor; ECM can control or block pathogens to invade trees; ECM can activate resistance-related enzymes of the hosts; it also can form rhizosphere microbial colony and establish root-rhizosphere micro-ecological environment. So mycorrhizal technology has become one of the most important methods of ecological control and biological control of plant diseases. This paper summarizes the application and development of ECM in forest disease control and also raises some ideas on their theory and application researches in the future.

  6. Durable strategies to deploy plant resistance in agricultural landscapes.

    Science.gov (United States)

    Fabre, Frédéric; Rousseau, Elsa; Mailleret, Ludovic; Moury, Benoit

    2012-03-01

    The deployment of resistant crops often leads to the emergence of resistance-breaking pathogens that suppress the yield benefit provided by the resistance. Here, we theoretically explored how farmers' main leverages (resistant cultivar choice, resistance deployment strategy, landscape planning and cultural practices) can be best combined to achieve resistance durability while minimizing yield losses as a result of plant viruses. Assuming a gene-for-gene type of interaction, virus epidemics are modelled in a landscape composed of a mosaic of resistant and susceptible fields, subjected to seasonality, and a reservoir hosting viruses year-round. The model links the genetic and the epidemiological processes, shaping at nested scales the demogenetic dynamics of viruses. The choice of the resistance gene (characterized by the equilibrium frequency of the resistance-breaking virus at mutation-selection balance in a susceptible plant) is the most influential leverage of action. Our results showed that optimal strategies of resistance deployment range from 'mixture' (where susceptible and resistant cultivars coexist) to 'pure' strategies (with only resistant cultivar) depending on the resistance characteristics and the epidemiological context (epidemic incidence and landscape connectivity). We demonstrate and discuss gaps concerning virus epidemiology across the agro-ecological interface that must be filled to achieve sustainable disease management.

  7. Engineered resistance against fungal plant pathogens

    NARCIS (Netherlands)

    Honée, G.

    1999-01-01

    Development of genetic engineering technology and molecular characterization of plant defense responses have provided strategies for controlling plant diseases additional to those based on chemical control or classical breeding programs. Most of these alternative strategies are based on the overprod

  8. The evolution of resistance gene in plants

    Institute of Scientific and Technical Information of China (English)

    BEN Haiyan; LIU Xuemin; LI Lijun; LIU Li

    2007-01-01

    Resistance genes enable plants to fight against plant pathogens. Plant resistance genes (R gene) are organized complexly in genome. Some resistance gene sequence data enable an insight into R gene structure and gene evolution. Some sites like Leucine-Rich Repeat (LRR) are of specific interest since homologous recombination can happen. Crossing over, transposon insertion and excision and mutation can produce new specificity. Three models explaining R gene evolution were discussed. More information needed for dissection of R gene evolution though some step can be inferred from genetic and sequence analysis.

  9. Current Understandings of Plant Nonhost Resistance.

    Science.gov (United States)

    Lee, Hyun-Ah; Lee, Hye-Young; Seo, Eunyoung; Lee, Joohyun; Kim, Saet-Byul; Oh, Soohyun; Choi, Eunbi; Choi, Eunhye; Lee, So Eui; Choi, Doil

    2017-01-01

    Nonhost resistance, a resistance of plant species against all nonadapted pathogens, is considered the most durable and efficient immune system of plants but yet remains elusive. The underlying mechanism of nonhost resistance has been investigated at multiple levels of plant defense for several decades. In this review, we have comprehensively surveyed the latest literature on nonhost resistance in terms of preinvasion, metabolic defense, pattern-triggered immunity, effector-triggered immunity, defense signaling, and possible application in crop protection. Overall, we summarize the current understanding of nonhost resistance mechanisms. Pre- and postinvasion is not much deviated from the knowledge on host resistance, except for a few specific cases. Further insights on the roles of the pattern recognition receptor gene family, multiple interactions between effectors from nonadapted pathogen and plant factors, and plant secondary metabolites in host range determination could expand our knowledge on nonhost resistance and provide efficient tools for future crop protection using combinational biotechnology approaches. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

  10. Quantitative disease resistance and quantitative resistance Loci in breeding.

    Science.gov (United States)

    St Clair, Dina A

    2010-01-01

    Quantitative disease resistance (QDR) has been observed within many crop plants but is not as well understood as qualitative (monogenic) disease resistance and has not been used as extensively in breeding. Mapping quantitative trait loci (QTLs) is a powerful tool for genetic dissection of QDR. DNA markers tightly linked to quantitative resistance loci (QRLs) controlling QDR can be used for marker-assisted selection (MAS) to incorporate these valuable traits. QDR confers a reduction, rather than lack, of disease and has diverse biological and molecular bases as revealed by cloning of QRLs and identification of the candidate gene(s) underlying QRLs. Increasing our biological knowledge of QDR and QRLs will enhance understanding of how QDR differs from qualitative resistance and provide the necessary information to better deploy these resources in breeding. Application of MAS for QRLs in breeding for QDR to diverse pathogens is illustrated by examples from wheat, barley, common bean, tomato, and pepper. Strategies for optimum deployment of QRLs require research to understand effects of QDR on pathogen populations over time.

  11. TRANSGENIC PLANTS RESISTANT TO INSECTS

    Directory of Open Access Journals (Sweden)

    S. Kereša

    2009-09-01

    Full Text Available Proteinase inhibitors are secondary metabolites present in all plants and it seems that their major role is protection of plants against attacks of animals, insects and microorganisms. One of the family of proteinase inhibitors are squash inhibitors of serine proteinases purified from seeds belonging to genera Cucurbita, Cucumis and Momordica. Squash inhibitors consist of 29-32 amino acid residues and are considered to be the smallest inhibitors of the serine proteinases known. Because of shortness, genes for these inhibitors could be synthesised and modified at different ways. Modifications could lead to changes in inhibitor activity. Tobacco as a model plant was transformed with 12 different genes of squash inhibitors. Stable integration of transgenes in putative transgenic plants was determined by PCR analysis using genomic DNA and primers that anneal to promoter and terminator region. The first step of proteinase inhibitor gene expression in transgenic plants was revealed by RT-PCR analysis. In entomological tests where larvae were fed with leaves, influence of transgenic T0 plants, as well as non-transgenic control plants on retardation of larval growth of S. littoralis was examined. Results of entomological tests showed that it is possible to express squash proteinase inhibitors in plants at level that significantly reduces S. littoralis larval growth.

  12. Induced systemic resistance (ISR) in plants: mechanism of action.

    Science.gov (United States)

    Choudhary, Devendra K; Prakash, Anil; Johri, B N

    2007-12-01

    Plants possess a range of active defense apparatuses that can be actively expressed in response to biotic stresses (pathogens and parasites) of various scales (ranging from microscopic viruses to phytophagous insect). The timing of this defense response is critical and reflects on the difference between coping and succumbing to such biotic challenge of necrotizing pathogens/parasites. If defense mechanisms are triggered by a stimulus prior to infection by a plant pathogen, disease can be reduced. Induced resistance is a state of enhanced defensive capacity developed by a plant when appropriately stimulated. Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are two forms of induced resistance wherein plant defenses are preconditioned by prior infection or treatment that results in resistance against subsequent challenge by a pathogen or parasite. Selected strains of plant growth-promoting rhizobacteria (PGPR) suppress diseases by antagonism between the bacteria and soil-borne pathogens as well as by inducing a systemic resistance in plant against both root and foliar pathogens. Rhizobacteria mediated ISR resembles that of pathogen induced SAR in that both types of induced resistance render uninfected plant parts more resistant towards a broad spectrum of plant pathogens. Several rhizobacteria trigger the salicylic acid (SA)-dependent SAR pathway by producing SA at the root surface whereas other rhizobacteria trigger different signaling pathway independent of SA. The existence of SA-independent ISR pathway has been studied in Arabidopsis thaliana, which is dependent on jasmonic acid (JA) and ethylene signaling. Specific Pseudomonas strains induce systemic resistance in viz., carnation, cucumber, radish, tobacco, and Arabidopsis, as evidenced by an enhanced defensive capacity upon challenge inoculation. Combination of ISR and SAR can increase protection against pathogens that are resisted through both pathways besides extended protection to a

  13. Association mapping of plant resistance to insects.

    Science.gov (United States)

    Kloth, Karen J; Thoen, Manus P M; Bouwmeester, Harro J; Jongsma, Maarten A; Dicke, Marcel

    2012-05-01

    Association mapping is rapidly becoming an important method to explore the genetic architecture of complex traits in plants and offers unique opportunities for studying resistance to insect herbivores. Recent studies indicate that there is a trade-off between resistance against generalist and specialist insects. Most studies, however, use a targeted approach that will easily miss important components of insect resistance. Genome-wide association mapping provides a comprehensive approach to explore the whole array of plant defense mechanisms in the context of the generalist-specialist paradigm. As association mapping involves the screening of large numbers of plant lines, specific and accurate high-throughput phenotyping (HTP) methods are needed. Here, we discuss the prospects of association mapping for insect resistance and HTP requirements.

  14. Insulin Resistance in Alzheimer's Disease

    Science.gov (United States)

    Dineley, Kelly T; Jahrling, Jordan B; Denner, Larry

    2014-01-01

    Insulin is a key hormone regulating metabolism. Insulin binding to cell surface insulin receptors engages many signaling intermediates operating in parallel and in series to control glucose, energy, and lipids while also regulating mitogenesis and development. Perturbations in the function of any of these intermediates, which occur in a variety of diseases, cause reduced sensitivity to insulin and insulin resistance with consequent metabolic dysfunction. Chronic inflammation ensues which exacerbates compromised metabolic homeostasis. Since insulin has a key role in learning and memory as well as directly regulating ERK, a kinase required for the type of learning and memory compromised in early Alzheimer's disease (AD), insulin resistance has been identified as a major risk factor for the onset of AD. Animal models of AD or insulin resistance or both demonstrate that AD pathology and impaired insulin signaling form a reciprocal relationship. Of note are human and animal model studies geared toward improving insulin resistance that have led to the identification of the nuclear receptor and transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ) as an intervention tool for early AD. Strategic targeting of alternate nodes within the insulin signaling network has revealed disease-stage therapeutic windows in animal models that coalesce with previous and ongoing clinical trial approaches. Thus, exploiting the connection between insulin resistance and AD provides powerful opportunities to delineate therapeutic interventions that slow or block the pathogenesis of AD. PMID:25237037

  15. Insulin resistance in Alzheimer's disease.

    Science.gov (United States)

    Dineley, Kelly T; Jahrling, Jordan B; Denner, Larry

    2014-12-01

    Insulin is a key hormone regulating metabolism. Insulin binding to cell surface insulin receptors engages many signaling intermediates operating in parallel and in series to control glucose, energy, and lipids while also regulating mitogenesis and development. Perturbations in the function of any of these intermediates, which occur in a variety of diseases, cause reduced sensitivity to insulin and insulin resistance with consequent metabolic dysfunction. Chronic inflammation ensues which exacerbates compromised metabolic homeostasis. Since insulin has a key role in learning and memory as well as directly regulating ERK, a kinase required for the type of learning and memory compromised in early Alzheimer's disease (AD), insulin resistance has been identified as a major risk factor for the onset of AD. Animal models of AD or insulin resistance or both demonstrate that AD pathology and impaired insulin signaling form a reciprocal relationship. Of note are human and animal model studies geared toward improving insulin resistance that have led to the identification of the nuclear receptor and transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ) as an intervention tool for early AD. Strategic targeting of alternate nodes within the insulin signaling network has revealed disease-stage therapeutic windows in animal models that coalesce with previous and ongoing clinical trial approaches. Thus, exploiting the connection between insulin resistance and AD provides powerful opportunities to delineate therapeutic interventions that slow or block the pathogenesis of AD. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Chapter 15. Plant pathology and managing wildland plant disease systems

    Science.gov (United States)

    David L. Nelson

    2004-01-01

    Obtaining specific, reliable knowledge on plant diseases is essential in wildland shrub resource management. However, plant disease is one of the most neglected areas of wildland resources experimental research. This section is a discussion of plant pathology and how to use it in managing plant disease systems.

  17. Review of Studies on Rare Earth against Plant Disease

    Institute of Scientific and Technical Information of China (English)

    慕康国; 张文吉; 崔建宇; 张福锁; 胡林

    2004-01-01

    Agricultural application of rare earth (RE) has been generalized for several decades, and it is involved in crops, vegetables and stock raising in China. However, all the researches on RE mainly focus on the fields such as plant physiological activity, physiological and biochemical mechanism, sanitation toxicology and environmental security. Plant protection by using RE and the induced resistance of plant against diseases were summarized. The mechanism of rare earth against plant disease is highlighted, which includes following two aspects. First, RE elements can control some phytopathogen directly and reduce its virulence to host plant. Another possibility is that RE elements can affect host plant and induce the plant to produce some resistance to disease.

  18. GhMPK7, a novel multiple stress-responsive cotton group C MAPK gene, has a role in broad spectrum disease resistance and plant development.

    Science.gov (United States)

    Shi, Jing; An, Hai-Long; Zhang, Liang; Gao, Zheng; Guo, Xing-Qi

    2010-09-01

    Mitogen-activated protein kinase (MAPK) cascades play a pivotal role in environmental responses and developmental processes in plants. Previous researches mainly focus on the MAPKs in groups A and B, and little is known on group C. In this study, we isolated and characterized GhMPK7, which is a novel gene from cotton belonging to the group C MAPK. RNA blot analysis indicated that GhMPK7 transcript was induced by pathogen infection and multiple defense-related signal molecules. Transgenic Nicotina benthamiana overexpressing GhMPK7 displayed significant resistance to fungus Colletotrichum nicotianae and virus PVY, and the transcript levels of SA pathway genes were more rapidly and strongly induced. Furthermore, the transgenic N. benthamiana showed reduced ROS-mediated injuries by upregulating expression of oxidative stress-related genes. Interestingly, the transgenic plants germinated earlier and grew faster in comparison to wild-type plants. beta-glucuronidase activity driven by the GhMPK7 promoter was detected in the apical meristem at the vegetative stage, and it was enhanced by treatments with signal molecules and phytohormones. These results suggest that GhMPK7 might play an important role in SA-regulated broad-spectrum resistance to pathogen infection, and that it is also involved in regulation of plant growth and development.

  19. Enhanced Tomato Disease Resistance Primed by Arbuscular Mycorrhizal Fungus

    Directory of Open Access Journals (Sweden)

    Yuanyuan eSong

    2015-09-01

    Full Text Available Roots of most terrestrial plants form symbiotic associations (mycorrhiza with soil- borne arbuscular mycorrhizal fungi (AMF. Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill. early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL and lipoxygenase (LOX in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related (PR proteins, PR1, PR2 and PR3, as well as defense-related genes LOX, AOC and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT plant, a jasmonate (JA biosynthesis mutant (spr2, and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for

  20. Enhanced tomato disease resistance primed by arbuscular mycorrhizal fungus

    Science.gov (United States)

    Song, Yuanyuan; Chen, Dongmei; Lu, Kai; Sun, Zhongxiang; Zeng, Rensen

    2015-01-01

    Roots of most terrestrial plants form symbiotic associations (mycorrhiza) with soil- borne arbuscular mycorrhizal fungi (AMF). Many studies show that mycorrhizal colonization enhances plant resistance against pathogenic fungi. However, the mechanism of mycorrhiza-induced disease resistance remains equivocal. In this study, we found that mycorrhizal inoculation with AMF Funneliformis mosseae significantly alleviated tomato (Solanum lycopersicum Mill.) early blight disease caused by Alternaria solani Sorauer. AMF pre-inoculation led to significant increases in activities of β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) in tomato leaves upon pathogen inoculation. Mycorrhizal inoculation alone did not influence the transcripts of most genes tested. However, pathogen attack on AMF-inoculated plants provoked strong defense responses of three genes encoding pathogenesis-related proteins, PR1, PR2, and PR3, as well as defense-related genes LOX, AOC, and PAL, in tomato leaves. The induction of defense responses in AMF pre-inoculated plants was much higher and more rapid than that in un-inoculated plants in present of pathogen infection. Three tomato genotypes: a Castlemart wild-type (WT) plant, a jasmonate (JA) biosynthesis mutant (spr2), and a prosystemin-overexpressing 35S::PS plant were used to examine the role of the JA signaling pathway in AMF-primed disease defense. Pathogen infection on mycorrhizal 35S::PS plants led to higher induction of defense-related genes and enzymes relative to WT plants. However, pathogen infection did not induce these genes and enzymes in mycorrhizal spr2 mutant plants. Bioassays showed that 35S::PS plants were more resistant and spr2 plants were more susceptible to early blight compared with WT plants. Our finding indicates that mycorrhizal colonization enhances tomato resistance to early blight by priming systemic defense response, and the JA signaling pathway is essential for mycorrhiza

  1. NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

    Directory of Open Access Journals (Sweden)

    Yasuyo Sekiyama

    2017-01-01

    Full Text Available Cercospora leaf spot (CLS is one of the most serious leaf diseases for sugar beet (Beta vulgaris L. worldwide. The breeding of sugar beet cultivars with both high CLS resistance and high yield is a major challenge for breeders. In this study, we report the nuclear magnetic resonance (NMR-based metabolic profiling of field-grown leaves for a subset of sugar beet genotypes harbouring different levels of CLS resistance. Leaves were collected from 12 sugar beet genotypes at four time points: seedling, early growth, root enlargement, and disease development stages. 1H-NMR spectra of foliar metabolites soluble in a deuterium-oxide (D2O-based buffer were acquired and subjected to multivariate analyses. A principal component analysis (PCA of the NMR data from the sugar beet leaves shows clear differences among the growth stages. At the later time points, the sugar and glycine betaine contents were increased, whereas the choline content was decreased. The relationship between the foliar metabolite profiles and resistance level to CLS was examined by combining partial least squares projection to latent structure (PLS or orthogonal PLS (OPLS analysis and univariate analyses. It was difficult to build a robust model for predicting precisely the disease severity indices (DSIs of each genotype; however, GABA and Gln differentiated susceptible genotypes (genotypes with weak resistance from resistant genotypes (genotypes with resistance greater than a moderate level before inoculation tests. The results suggested that breeders might exclude susceptible genotypes from breeding programs based on foliar metabolites profiled without inoculation tests, which require an enormous amount of time and effort.

  2. Transgenic Tobacco Plants With Efficient Insect Resistance

    Institute of Scientific and Technical Information of China (English)

    李太元; 田颖川; 秦晓峰; 莽克强; 李文谷; 何永刚; 沈蕾

    1994-01-01

    Insecticidal protein gene CryIA(c)from Bacillus thuringiensis HD-1(B.t.toxin gene)with 5’-end modified and 3’-end deleted to 4 different lengths were inserted downstream of 35S promoterwith double enhancer and"Ω’"fragment of TMV-RNA cDNA in the binary vector pBin438 to constructthe chimeric expression vector of B.t.toxin gene.Leave stripes of tobacco plant var.NC89 widelygrown in China were transformed with A.tumefaciens LBA4404 harbouring the above expression vectorsrespectively,and kanamycin resistant tobacco plants were regenerated.Insect test with tobacco budwormH.assulta showed that insect-resistant transform.ants could be obtained from the regenerated plantstransformed with B.t.genes of different lengths though highest percentage(~50%)of plants with ahigh morality(90%-100%)to the testing insects is among those transformed with 1.8-kb toxin gene.Genetic,molecular and biological analyses of T1 and T2 progenies of plants with high efficient insect re-sistance showed that B.t.toxin gene and the character of insect resistance have been inherited in the pro-genies.Insect-resistant homozygotes D8-14 and D19-8 have been selected for small-scale field tests.

  3. [RNA silencing and viral disease induction in plants].

    Science.gov (United States)

    Shimura, Hanako; Masuta, Chikara

    2012-06-01

    RNA silencing plays an important role in plant resistance against viruses. As a counter-defense against RNA silencing, plant viruses have evolved RNA silencing suppressors (RSSs). RNA silencing is likely to play a major role in disease development. For example, RSSs have been found to disturb the gene expression controlled by miRNAs in plant tissue and organ development, resulting in plant malformation. Mosaic symptoms, which are typical in virus-infected plants, are actually a consequence of local arms race between host RNA silencing and viral RSSs. In addition, recent studies revealed that viral siRNAs could induce RNA silencing even against a certain host gene and thus a disease symptom through a complementary (homologous) sequence coincidentally found between virus and host gene. RNA silencing is the principal mediator of viral pathogenicity and disease induction and therefore should be exploited as a powerful tool for engineering virus resistance in plants as well as in animals.

  4. A novel approach for multi-domain and multi-gene family identification provides insights into evolutionary dynamics of disease resistance genes in core eudicot plants.

    Science.gov (United States)

    Hofberger, Johannes A; Zhou, Beifei; Tang, Haibao; Jones, Jonathan D G; Schranz, M Eric

    2014-11-08

    Recent advances in DNA sequencing techniques resulted in more than forty sequenced plant genomes representing a diverse set of taxa of agricultural, energy, medicinal and ecological importance. However, gene family curation is often only inferred from DNA sequence homology and lacks insights into evolutionary processes contributing to gene family dynamics. In a comparative genomics framework, we integrated multiple lines of evidence provided by gene synteny, sequence homology and protein-based Hidden Markov Modelling to extract homologous super-clusters composed of multi-domain resistance (R)-proteins of the NB-LRR type (for NUCLEOTIDE BINDING/LEUCINE-RICH REPEATS), that are involved in plant innate immunity. To assess the diversity of R-proteins within and between species, we screened twelve eudicot plant genomes including six major crops and found a total of 2,363 NB-LRR genes. Our curated R-proteins set shows a 50% average for tandem duplicates and a 22% fraction of gene copies retained from ancient polyploidy events (ohnologs). We provide evidence for strong positive selection and show significant differences in molecular evolution rates (Ka/Ks-ratio) among tandem- (mean = 1.59), ohnolog (mean = 1.36) and singleton (mean = 1.22) R-gene duplicates. To foster the process of gene-edited plant breeding, we report species-specific presence/absence of all 140 NB-LRR genes present in the model plant Arabidopsis and describe four distinct clusters of NB-LRR "gatekeeper" loci sharing syntenic orthologs across all analyzed genomes. By curating a near-complete set of multi-domain R-protein clusters in an eudicot-wide scale, our analysis offers significant insight into evolutionary dynamics underlying diversification of the plant innate immune system. Furthermore, our methods provide a blueprint for future efforts to identify and more rapidly clone functional NB-LRR genes from any plant species.

  5. 植物抗病机制及信号转导的研究进展%Research Advances in the Mechanism and Signal Transduction of Plant Disease Resistance

    Institute of Scientific and Technical Information of China (English)

    丁丽娜; 杨国兴

    2016-01-01

    The mechanism of plant disease resistance is the focus of plant pathology. With the development of the molecular biology, people has gained more and more insights into the interaction between plant host and pathogens. In this review,the recent research advances on molecular mechanism of plants disease resistance are summarized. It also presented the function of several signal molecular such as calcium Ion,nitric oxide,reactive oxygen species,salicylic acid,jasmonic acid/ethylene,and heterotrimeric G proteins,which are known to play important role in inducing plant defense response. In addition,the prospect of future work on plant defense research is discussed in the review, aiming to offer new thinking for the development of disease control stratey.%植物的抗病机制是植物病理学研究的重点。随着分子生物学的不断发展,人们对植物与病原之间的互作机制有了更多的了解。综述了近年来植物抗病分子机制方面的研究进展,同时阐述了钙离子、活性氧、水杨酸、茉莉酸\\乙烯、一氧化氮及异源三聚体 G 蛋白等信号分子介导的信号转导途径在诱导植物防卫反应中的作用,并对今后的研究前景进行了展望。旨为病害防治提供思路。

  6. Evaluation on Diseases Resistance of Cotton Material and Its Utilization

    Institute of Scientific and Technical Information of China (English)

    ZENG Hua-lan; HE Lian; YE Peng-sheng; ZHANG Yu; WEI Shu-gu

    2008-01-01

    @@ Fusarium wilt and Verticillium wilt are important worldwide fungal diseases on cotton that cause damage to yield and quality.The pathogens survive in soil as microsclerotia for many years,and can be transmitted through seeds,soil,stream,and plant residues.And currently,no effective chemical control is available for those diseases.Production practices have established that planting wilt diseaseresistance varieties was one of the most effective and safe measures to control those diseases with low cost.However,screening for wilt-resistance germplasm resources is the basis for resistance breeding.

  7. 植物脂肪酸及其衍生物防御信号研究进展%Progress on Fatty Acids and Their Derivatives-mediated Signaling Pathways in Plant Disease Resistance

    Institute of Scientific and Technical Information of China (English)

    汤丽川; 赵永亮; 毛龙; 李爱丽

    2012-01-01

    植物由于不能移动而发展了复杂而精密的抗病系统.近年来,人们发现作为细胞膜组分的脂肪酸在植物的各种抗病机制中发挥着举足轻重的作用.脂肪酸及其衍生物不仅参与植物基础免疫和系统免疫,还参与经典抗病基因(R基因)介导的抗病过程.目前,已发现许多与脂肪酸(尤其是16碳和18碳脂肪酸及其衍生物)代谢相关的突变体,对这些突变体抗病性政变的分子机制研究成为植物抗病领域研究热点之一.本文综述了脂肪酸及其衍生物在植物防御信号转导中的最新研究进展,旨在为植物抗病遗传育种研究提供新的参考.%The sessile plants have developed complicated but sophisticated disease resistance systems. In recent years,fatty acids (FAs),the common cell membrane components,have been found to play important signaling roles in various disease resistance mechanisms. Fatty acids,especially 16- and 18-carbon derivatives,not only participate in both plant basal and systemic immunity,but also are required for the classical R gene mediated resistance mechanism. To date,many mutants have been found to be involved in the metabolism of fatty acid (especially the fatty acids having 16 or 18 carbons,or their derivatives). And the mechanisms about how these mutants changing their resistance to diseases have become a hotspot in the field of plant pathogen defense. This article has reviewed the recent progresses on how the fatty acid and its derivatives acting in the signaling pathways of plant defense,and aimed to contribute to the breeding of disease-resistant plants.

  8. Mechanisms of resistance to paraquat in plants.

    Science.gov (United States)

    Hawkes, Timothy R

    2014-09-01

    The aim of this brief review is to draw information from studies of the mechanism of evolved resistance in weeds, together with information from laboratory studies of paraquat tolerance in model plants. Plants having mutations that limit paraquat uptake into cytoplasm, that confer various stress tolerances or that have transgenes that co-express two or more of the chloroplast Halliwell-Asada cycle enzymes can all exhibit enhanced tolerance to paraquat. However, none of these mechanisms correspond to the high-level resistances that have evolved naturally in weeds. Most, but not all, of the evidence from studies of paraquat-resistant biotypes of weeds can reasonably be reconciled with the proposal of a single major gene mechanism that sequesters paraquat away from chloroplasts and into the vacuole. However, the molecular details of this putative mechanism remain ill-defined.

  9. Frost resistance in alpine woody plants.

    Science.gov (United States)

    Neuner, Gilbert

    2014-01-01

    This report provides a brief review of key findings related to frost resistance in alpine woody plant species, summarizes data on their frost resistance, highlights the importance of freeze avoidance mechanisms, and indicates areas of future research. Freezing temperatures are possible throughout the whole growing period in the alpine life zone. Frost severity, comprised of both intensity and duration, becomes greater with increasing elevation and, there is also a greater probability, that small statured woody plants, may be insulated by snow cover. Several frost survival mechanisms have evolved in woody alpine plants in response to these environmental conditions. Examples of tolerance to extracellular freezing and freeze dehydration, life cycles that allow species to escape frost, and freeze avoidance mechanisms can all be found. Despite their specific adaption to the alpine environment, frost damage can occur in spring, while all alpine woody plants have a low risk of frost damage in winter. Experimental evidence indicates that premature deacclimation in Pinus cembra in the spring, and a limited ability of many species of alpine woody shrubs to rapidly reacclimate when they lose snow cover, resulting in reduced levels of frost resistance in the spring, may be particularly critical under the projected changes in climate. In this review, frost resistance and specific frost survival mechanisms of different organs (leaves, stems, vegetative and reproductive over-wintering buds, flowers, and fruits) and tissues are compared. The seasonal dynamics of frost resistance of leaves of trees, as opposed to woody shrubs, is also discussed. The ability of some tissues and organs to avoid freezing by supercooling, as visualized by high resolution infrared thermography, are also provided. Collectively, the report provides a review of the complex and diverse ways that woody plants survive in the frost dominated environment of the alpine life zone.

  10. The Resistance of Crops in Plant Protection

    Institute of Scientific and Technical Information of China (English)

    MIRZAEVA Gulnara

    2008-01-01

    @@ World crop production requires highly-productive varieties of agricultural crops,which are resistant to pest organisms.Such varieties are also of great importance for the Uzbekistan.Their deficiency may prove to be an obstacle to securing the production of foodstuffs and providing commerce with agricultural products.The cultivation of varieties,which are resistant to insects and mites,provides an opportunity to decrease the number of applied insecticides and acaricides.In addition to the considerable economic advantage,including energy consumption,the growing of resistant varieties is of great ecological importance,protecting environment and health (as a result the risk of chemical pollution becomes less and conditions for agricultural workers are improved).All this,allows us to state that exploration of the theoretical basis of plant resistance to pests and the selection of resistant arieties are a fundamental scientific and real national economic problems.It is known that an immunogenetic system of any organism is called up to protect their morpho-functional integrity.Plant resistance to in sects and mites,as well as other mesophauna,is characterized by many factors that reflect the essence of versatile interrelations that arose in the evolutionary process.

  11. Fungicide resistance assays for fungal plant pathogens.

    Science.gov (United States)

    Secor, Gary A; Rivera, Viviana V

    2012-01-01

    Fungicide resistance assays are useful to determine if a fungal pathogen has developed resistance to a fungicide used to manage the disease it causes. Laboratory assays are used to determine loss of sensitivity, or resistance, to a fungicide and can explain fungicide failures and for developing successful fungicide recommendations in the field. Laboratory assays for fungicide resistance are conducted by measuring reductions in growth or spore germination of fungi in the presence of fungicide, or by molecular procedures. This chapter describes two techniques for measuring fungicide resistance, using the sugarbeet leaf spot fungus Cercospora beticola as a model for the protocol. Two procedures are described for fungicides from two different classes; growth reduction for triazole (sterol demethylation inhibitor; DMI) fungicides, and inhibition of spore germination for quinone outside inhibitor (QoI) fungicides.

  12. Interfamily transfer of a plant pattern-recognition receptor confers broad-spectrum bacterial resistance.

    Science.gov (United States)

    Lacombe, Séverine; Rougon-Cardoso, Alejandra; Sherwood, Emma; Peeters, Nemo; Dahlbeck, Douglas; van Esse, H Peter; Smoker, Matthew; Rallapalli, Ghanasyam; Thomma, Bart P H J; Staskawicz, Brian; Jones, Jonathan D G; Zipfel, Cyril

    2010-04-01

    Plant diseases cause massive losses in agriculture. Increasing the natural defenses of plants may reduce the impact of phytopathogens on agricultural productivity. Pattern-recognition receptors (PRRs) detect microbes by recognizing conserved pathogen-associated molecular patterns (PAMPs). Although the overall importance of PAMP-triggered immunity for plant defense is established, it has not been used to confer disease resistance in crops. We report that activity of a PRR is retained after its transfer between two plant families. Expression of EFR (ref. 4), a PRR from the cruciferous plant Arabidopsis thaliana, confers responsiveness to bacterial elongation factor Tu in the solanaceous plants Nicotiana benthamiana and tomato (Solanum lycopersicum), making them more resistant to a range of phytopathogenic bacteria from different genera. Our results in controlled laboratory conditions suggest that heterologous expression of PAMP recognition systems could be used to engineer broad-spectrum disease resistance to important bacterial pathogens, potentially enabling more durable and sustainable resistance in the field.

  13. Sweet smells prepare plants for future stress: airborne induction of plant disease immunity.

    Science.gov (United States)

    Yi, Hwe-Su; Ryu, Choong-Min; Heil, Martin

    2010-05-01

    Plants require protection against a wide range of attackers such as insects and pathogens. The adequate plant defense responses are regulated via sophisticated signal cascades, which are activated following the perception of specific cues of the attackers. Plants might, however, gain a significant fitness advantage when pre-empting enemy attack before it actually occurs. Monitoring cues from attacked neighbors can permit plants to reach this goal. We have recently found airborne disease resistance against a bacterial pathogen in uninfected lima bean plants when these were located close to conspecific, resistance-expressing neighbors. The emitters could be chemically induced with benzothiadiazole or biologically with an avirulent pathogen. Unexpectedly, receiver plants, although expressing a functioning resistance, did not show reduced growth rates, which represent a common side-effect of directly induced pathogen resistance. Nonanal was identified as an active volatile and, rather than directly inducing full resistance, primed defense gene expression, which became fully activated only when the plants were subsequently challenged by a virulent pathogen. Priming by airborne signals allows for a more efficient and less costly preparation of plants for future attack and airborne signaling can affect resistance against both major groups of plant enemies: herbivores and pathogens.

  14. Insulin Resistance and Skin Diseases

    Directory of Open Access Journals (Sweden)

    Maddalena Napolitano

    2015-01-01

    Full Text Available In medical practice, almost every clinician may encounter patients with skin disease. However, it is not always easy for physicians of all specialties to face the daily task of determining the nature and clinical implication of dermatologic manifestations. Are they confined to the skin, representing a pure dermatologic event? Or are they also markers of internal conditions relating to the patient’s overall health? In this review, we will discuss the principal cutaneous conditions which have been linked to metabolic alterations. Particularly, since insulin has an important role in homeostasis and physiology of the skin, we will focus on the relationships between insulin resistance (IR and skin diseases, analyzing strongly IR-associated conditions such as acanthosis nigricans, acne, and psoriasis, without neglecting emerging and potential scenarios as the ones represented by hidradenitis suppurativa, androgenetic alopecia, and hirsutism.

  15. The Evolutionary Ecology of Plant Disease: A Phylogenetic Perspective.

    Science.gov (United States)

    Gilbert, Gregory S; Parker, Ingrid M

    2016-08-04

    An explicit phylogenetic perspective provides useful tools for phytopathology and plant disease ecology because the traits of both plants and microbes are shaped by their evolutionary histories. We present brief primers on phylogenetic signal and the analytical tools of phylogenetic ecology. We review the literature and find abundant evidence of phylogenetic signal in pathogens and plants for most traits involved in disease interactions. Plant nonhost resistance mechanisms and pathogen housekeeping functions are conserved at deeper phylogenetic levels, whereas molecular traits associated with rapid coevolutionary dynamics are more labile at branch tips. Horizontal gene transfer disrupts the phylogenetic signal for some microbial traits. Emergent traits, such as host range and disease severity, show clear phylogenetic signals. Therefore pathogen spread and disease impact are influenced by the phylogenetic structure of host assemblages. Phylogenetically rare species escape disease pressure. Phylogenetic tools could be used to develop predictive tools for phytosanitary risk analysis and reduce disease pressure in multispecies cropping systems.

  16. Induced resistance in plants and the role of pathogenesis-related proteins

    NARCIS (Netherlands)

    Loon, L.C. van

    2001-01-01

    The nature of induced resistance Resistance, according to Agrios (1988) is the ability of an organism to exclude or overcome, completely or in some degree, the effect of a pathogen or other damaging factor. Disease resistance in plants is manifested by limited symptoms, reflecting the inability of t

  17. Metal Hyperaccumulation Armors Plants against Disease

    Science.gov (United States)

    Fones, Helen; Davis, Calum A. R.; Rico, Arantza; Fang, Fang; Smith, J. Andrew C.; Preston, Gail M.

    2010-01-01

    Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the ‘elemental defense’ hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a hyperaccumulator of zinc, nickel, and cadmium, and the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm). Using leaf inoculation assays, we have shown that hyperaccumulation of any of the three metals inhibits growth of Psm in planta. Metal concentrations in the bulk leaf and in the apoplast, through which the pathogen invades the leaf, were shown to be sufficient to account for the defensive effect by comparison with in vitro dose–response curves. Further, mutants of Psm with increased and decreased zinc tolerance created by transposon insertion had either enhanced or reduced ability, respectively, to grow in high-zinc plants, indicating that the metal affects the pathogen directly. Finally, we have shown that bacteria naturally colonizing T. caerulescens leaves at the site of a former lead–zinc mine have high zinc tolerance compared with bacteria isolated from non-accumulating plants, suggesting local adaptation to high metal. These results demonstrate that the disease resistance observed in metal-exposed T. caerulescens can be attributed to a direct effect of metal hyperaccumulation, which may thus be functionally analogous to the resistance conferred by antimicrobial metabolites in non-accumulating plants. PMID:20838462

  18. Metal hyperaccumulation armors plants against disease.

    Directory of Open Access Journals (Sweden)

    Helen Fones

    2010-09-01

    Full Text Available Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the 'elemental defense' hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a hyperaccumulator of zinc, nickel, and cadmium, and the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm. Using leaf inoculation assays, we have shown that hyperaccumulation of any of the three metals inhibits growth of Psm in planta. Metal concentrations in the bulk leaf and in the apoplast, through which the pathogen invades the leaf, were shown to be sufficient to account for the defensive effect by comparison with in vitro dose-response curves. Further, mutants of Psm with increased and decreased zinc tolerance created by transposon insertion had either enhanced or reduced ability, respectively, to grow in high-zinc plants, indicating that the metal affects the pathogen directly. Finally, we have shown that bacteria naturally colonizing T. caerulescens leaves at the site of a former lead-zinc mine have high zinc tolerance compared with bacteria isolated from non-accumulating plants, suggesting local adaptation to high metal. These results demonstrate that the disease resistance observed in metal-exposed T. caerulescens can be attributed to a direct effect of metal hyperaccumulation, which may thus be functionally analogous to the resistance conferred by antimicrobial metabolites in non-accumulating plants.

  19. Metal hyperaccumulation armors plants against disease.

    Science.gov (United States)

    Fones, Helen; Davis, Calum A R; Rico, Arantza; Fang, Fang; Smith, J Andrew C; Preston, Gail M

    2010-09-09

    Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the 'elemental defense' hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a hyperaccumulator of zinc, nickel, and cadmium, and the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm). Using leaf inoculation assays, we have shown that hyperaccumulation of any of the three metals inhibits growth of Psm in planta. Metal concentrations in the bulk leaf and in the apoplast, through which the pathogen invades the leaf, were shown to be sufficient to account for the defensive effect by comparison with in vitro dose-response curves. Further, mutants of Psm with increased and decreased zinc tolerance created by transposon insertion had either enhanced or reduced ability, respectively, to grow in high-zinc plants, indicating that the metal affects the pathogen directly. Finally, we have shown that bacteria naturally colonizing T. caerulescens leaves at the site of a former lead-zinc mine have high zinc tolerance compared with bacteria isolated from non-accumulating plants, suggesting local adaptation to high metal. These results demonstrate that the disease resistance observed in metal-exposed T. caerulescens can be attributed to a direct effect of metal hyperaccumulation, which may thus be functionally analogous to the resistance conferred by antimicrobial metabolites in non-accumulating plants.

  20. Structure-based computational study of two disease resistance gene homologues (Hm1 and Hm2) in maize (Zea mays L.) with implications in plant-pathogen interactions.

    Science.gov (United States)

    Dehury, Budheswar; Patra, Mahesh Chandra; Maharana, Jitendra; Sahu, Jagajjit; Sen, Priyabrata; Modi, Mahendra Kumar; Choudhury, Manabendra Dutta; Barooah, Madhumita

    2014-01-01

    The NADPH-dependent HC-toxin reductases (HCTR1 and 2) encoded by enzymatic class of disease resistance homologous genes (Hm1 and Hm2) protect maize by detoxifying a cyclic tetrapeptide, HC-toxin, secreted by the fungus Cochliobolus carbonum race 1(CCR1). Unlike the other classes' resistance (R) genes, HCTR-mediated disease resistance is an inimitable mechanism where the avirulence (Avr) component from CCR1 is not involved in toxin degradation. In this study, we attempted to decipher cofactor (NADPH) recognition and mode of HC-toxin binding to HCTRs through molecular docking, molecular dynamics (MD) simulations and binding free energy calculation methods. The rationality and the stability of docked complexes were validated by 30-ns MD simulation. The binding free energy decomposition of enzyme-cofactor complex was calculated to find the driving force behind cofactor recognition. The overall binding free energies of HCTR1-NADPH and HCTR2-NADPH were found to be -616.989 and -16.9749 kJ mol-1 respectively. The binding free energy decomposition revealed that the binding of NADPH to the HCTR1 is mainly governed by van der Waals and nonpolar interactions, whereas electrostatic terms play dominant role in stabilizing the binding mode between HCTR2 and NADPH. Further, docking analysis of HC-toxin with HCTR-NADPH complexes showed a distinct mode of binding and the complexes were stabilized by a strong network of hydrogen bond and hydrophobic interactions. This study is the first in silico attempt to unravel the biophysical and biochemical basis of cofactor recognition in enzymatic class of R genes in cereal crop maize.

  1. Effects of Thai medicinal plants on pathogenic bacterial, growth performance, health condition and disease resistance in black tiger shrimp (Penaeus monodon Fabricius

    Directory of Open Access Journals (Sweden)

    Klowkliang, T.

    2005-02-01

    Full Text Available Chemical analysis of turmeric (Curcuma longa extracts using TLC/densitometry, showed an extract contain 21.57%w/w of three important curcuminoids: curcumin, desmethoxycurcumin and bisdesmethoxycurcumin. GC and MS were used to analyze volatile oils. Aromatic turmerone, α-turmerone and zingiberene were also obtained. Qualitative and quantitative analyses alcoholic extract of Andrographis paniculata using TLC, revealed that the extracts contain three important compounds in total lactone of 30.49% w/w. There are andrographolide,14-deoxy-11-12-didehydroandrographolide and neoandrographolide. TLC-chromatogram of Clinacanthus nutans extract after reacted with anisaldehyde/sulfuric acid showed a 9 key compounds, while preliminary neutralization test of the compounds revealed that there were active compounds against HSV-1 virus. In vitro efficacy test revealed that Curcuma longa and Andrographis paniculata extracts at 250 and 1,500 mg/L could eradicate 15 isolates of Vibrio spp. which were isolated from infected shrimps. Effects of medicinal plant extracts incorporated into the diet on shrimp immune responses were investigated. Shrimp fed diet containing Clinacanthus nutans extract at 20 mg/kg of diet had good growth, FCR and immune responses. The shrimp that were fed diet containing Curcuma longa extracts at 25 mg/kg of diet for 7-14 days showed high resistance to Vibrio harveyi. Likewise, the shrimp fed Andrographis paniculata extract at 25 mg/ kg of diet for 14 days had a higher resistance to WSSV. Incorporating the medicinal extracts at higher levels resulted in reduction in diet palatability which consequently had an effect on a decrease in growth, immune responses and resistance to bacterial and WSSV infection.

  2. Engineering resistance to plant viruses: Present status and future prospects

    Science.gov (United States)

    Plant viruses cause severe crop losses across the globe. Resistant cultivars together with pesticide application are commonly used to avoid the losses caused by plant viruses. However, very limited success has been achieved at diminishing the impact of plant viruses. Use of virus resistant plant is ...

  3. Constitutive expression of pathogen-inducible OsWRKY31 enhances disease resistance and affects root growth and auxin response in transgenic rice plants

    Institute of Scientific and Technical Information of China (English)

    Juan Zhang; Youliang Peng; Zejian Guo

    2008-01-01

    WRKY transcription factors have many regulatory roles in response to biotic and abiotic stresses. In this study, we isolated a rice WRKY gene (OsWRKY31) that is induced by the rice blast fungus Magnaporthe grisea and auxin. This gene encodes a polypeptide of 211 amino-acid residues and belongs to a subgroup of the rice WRKY gene family that probably originated after the divergence of monocot and dicot plants. OsWRKY31 was found to be localized to the nucleus of onion epidermis cells to transiently express OsWRKY31-eGFP fusion protein. Analysis of 0sWRKY31 and its mutants fused with a Cal4 DNA-binding domain indicated that OsWRKY31 has transactivation activity in yeast. Overexpression of the OsWRKY31 gene was found to enhance resistance against infection with M. grisea, and the transgenic lines exhibited reduced lateral root formation and elongation compared with wild-type and RNAi plants. The lines with overexpression showed constitutive expression of many defense-related genes, such as PBZ1 and OsSci2, as well as early auxin-response genes, such as OsIAA4 and OsCrll genes. Furthermore, the plants with overexpression were less sensitive to exogenously supplied IBA, NAA and 2,4-D at high concentrations, suggesting that overexpression of the OsWRKY31 gene might alter the auxin response or transport. These results also suggest that OsWRKY31 might be a common component in the signal transduction pathways of the auxin response and the defense response in rice.

  4. Transgenic strategies to confer resistance against viruses in rice plants

    Directory of Open Access Journals (Sweden)

    Takahide eSasaya

    2014-01-01

    Full Text Available Rice (Oryza sativa L. is cultivated in more than 100 countries and supports nearly half of the world’s population. Developing efficient methods to control rice viruses is thus an urgent necessity because viruses cause serious losses in rice yield. Most rice viruses are transmitted by insect vectors, notably planthoppers and leafhoppers. Viruliferous insect vectors can disperse their viruses over relatively long distances, and eradication of the viruses is very difficult once they become widespread. Exploitation of natural genetic sources of resistance is one of the most effective approaches to protect crops from virus infection; however, only a few naturally occurring rice genes confer resistance against rice viruses. In an effort to improve control, many investigators are using genetic engineering of rice plants as a potential strategy to control viral diseases. Using viral genes to confer pathogen-derived resistance against crops is a well-established procedure, and the expression of various viral gene products has proved to be effective in preventing or reducing infection by various plant viruses since the 1990s. RNA-interference (RNAi, also known as RNA silencing, is one of the most efficient methods to confer resistance against plant viruses on their respective crops. In this article, we review the recent progress, mainly conducted by our research group, in transgenic strategies to confer resistance against tenuiviruses and reoviruses in rice plants. Our findings also illustrate that not all RNAi constructs against viral RNAs are equally effective in preventing virus infection and that it is important to identify the viral Achilles’ heel gene to target for RNAi attack when engineering plants.

  5. Fungal endophytes: modifiers of plant disease.

    Science.gov (United States)

    Busby, Posy E; Ridout, Mary; Newcombe, George

    2016-04-01

    Many recent studies have demonstrated that non-pathogenic fungi within plant microbiomes, i.e., endophytes ("endo" = within, "phyte" = plant), can significantly modify the expression of host plant disease. The rapid pace of advancement in endophyte ecology warrants a pause to synthesize our understanding of endophyte disease modification and to discuss future research directions. We reviewed recent literature on fungal endophyte disease modification, and here report on several emergent themes: (1) Fungal endophyte effects on plant disease span the full spectrum from pathogen antagonism to pathogen facilitation, with pathogen antagonism most commonly reported. (2) Agricultural plant pathosystems are the focus of research on endophyte disease modification. (3) A taxonomically diverse group of fungal endophytes can influence plant disease severity. And (4) Fungal endophyte effects on plant disease severity are context-dependent. Our review highlights the importance of fungal endophytes for plant disease across a broad range of plant pathosystems, yet simultaneously reveals that complexity within plant microbiomes presents a significant challenge to disentangling the biotic environmental factors affecting plant disease severity. Manipulative studies integrating eco-evolutionary approaches with emerging molecular tools will be poised to elucidate the functional importance of endophytes in natural plant pathosystems that are fundamental to biodiversity and conservation.

  6. Cellular basis of gravity resistance in plants

    Science.gov (United States)

    Hoson, Takayuki; Matsumoto, Shouhei; Inui, Kenichi; Zhang, Yan; Soga, Kouichi; Wakabayashi, Kazuyuki; Hashimoto, Takashi

    Mechanical resistance to the gravitational force is a principal gravity response in plants distinct from gravitropism. In the final step of gravity resistance, plants increase the rigidity of their cell walls via modifications to the cell wall metabolism and apoplastic environment. We studied cellular events that are related to the cell wall changes under hypergravity conditions produced by centrifugation. Hypergravity induced reorientation of cortical microtubules from transverse to longitudinal directions in epidermal cells of stem organs. In Arabidopsis tubulin mutants, the percentage of cells with longitudinal microtubules was high even at 1 g, and it was further increased by hypergravity. Hypocotyls of tubulin mutants also showed either left-handed or right-handed helical growth at 1 g, and the degree of twisting phenotype was intensified under hypergravity conditions. The left-handed helical growth mutants had right-handed microtubule arrays, whereas the right-handed mutant had left-handed arrays. There was a close correlation between the alignment angle of epidermal cell files and the alignment of cortical microtubules. Gadolinium ions suppressed both the twisting phenotype and reorientation of microtubules in tubulin mutants. These results support the hypothesis that cortical microtubules play an es-sential role in maintenance of normal growth phenotype against the gravitational force, and suggest that mechanoreceptors are involved in modifications to morphology and orientation of microtubule arrays by hypergravity. Actin microfilaments, in addition to microtubules, may be involved in gravity resistance. The nucleus of epidermal cells of azuki bean epicotyls, which is present almost in the center of the cell at 1 g, was displaced to the cell bottom by increasing the magnitude of gravity. Cytochalasin D stimulated the sedimentation by hypergravity of the nu-cleus, suggesting that the positioning of the nucleus is regulated by actin microfilaments, which is

  7. MARKER ASSISTED SELECTION IN DISEASE RESISTANCE BREEDING

    Directory of Open Access Journals (Sweden)

    Narasimhulu Ragimekula

    2013-08-01

    Full Text Available Feeding ever-increasing population is the main challenge faced by the agricultural scientists and to meet this plant breeders have to put continuous efforts to develop new crop varieties on fast track basis. DNA based polymorphism, commonly known as DNA markers can be used for genetic improvement through selection for favourable traits such as disease resistance. Molecular markers are becoming an essential component in backcross breeding programs for tracking the resistance genes in gene pyramiding. Marker assisted selection (MAS, is expected to increase genetic response by affecting efficiency and accuracy of selection. Even though marker-assisted selection now plays a prominent role in the field of plant breeding, examples of successful, practical outcomes are rare. MAS, with few exceptions, has not yet delivered its expected benefits in commercial breeding. It is clear that DNA markers hold great promise, but realizing that promise remains elusive. The economic and biological constraints such as a low return of investment in small-grain cereal breeding, lack of diagnostic markers, and the prevalence of QTL-background effects hinder the broad implementation of MAS. Until complex traits can be fully dissected, the application of MAS will be limited to genes of moderate-to-large effect and to applications that do not endanger the response to conventional selection. Till then, observable phenotype will remain an important component of genetic improvement programmes, because it takes in to account the collective effect of all genes. In future, chip-based, high-throughput genotyping platforms and the introduction of genomic selection will reduce the current problems of integrating MAS in practical breeding programs and open new avenues for a molecular-based resistance breeding.

  8. Silicon control of bacterial and viral diseases in plants

    Directory of Open Access Journals (Sweden)

    Sakr Nachaat

    2016-12-01

    Full Text Available Silicon plays an important role in providing tolerance to various abiotic stresses and augmenting plant resistance against diseases. However, there is a paucity of reports about the effect of silicon on bacterial and viral pathogens of plants. In general, the effect of silicon on plant resistance against bacterial diseases is considered to be due to either physical defense or increased biochemical defense. In this study, the interaction between silicon foliar or soil-treatments and reduced bacterial and viral severity was reviewed. The current review explains the agricultural importance of silicon in plants, refers to the control of bacterial pathogens in different crop plants by silicon application, and underlines the different mechanisms of silicon-enhanced resistance. A section about the effect of silicon in decreasing viral disease intensity was highlighted. By combining the data presented in this study, a better comprehension of the complex interaction between silicon foliar- or soil-applications and bacterial and viral plant diseases could be achieved.

  9. Bacterial Gibberellins Induce Systemic Resistance of Plants

    Directory of Open Access Journals (Sweden)

    I. N. FEKLISTOVA

    2014-06-01

    Full Text Available It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and poultry industries with high quality vegetable protein. It is used for biofuel production as well.Gibberellin preparation was isolated from liquid culture of strain Pseudomonas aurantiaca grown in 250 mL of M9 medium (48 h, 28 °C under darkroom conditions. Gibberellins were extracted according procedure described by Tien et al. (1979. Gibberellins concentration in the medium was determined by fluorometric method.Elicitor activity of bacterial metabolites – gibberellins – was analyzed in model system of artificial inoculation of oilseed rape germs with phytopathogenic fungi Alternaria brassicicola. The elicitor action efficiency was evaluated on the 15th day of oilseed rape cultivation based on the percentage of leaf surface covered by necrotic lesions.Gibberellins were shown to induce systemic resistance resulted in decreasing of oil seed plants   vulnerability by 52.7%.It is known that under the unfavorable conditions plants synthesis the reactive oxygen intermediates   which activate destructive processes. One of the first organism reactions to stress action is the change of the lipid peroxidation level. It was shown that treatment of the soil with gibberellins resulted in decreasing of the lipid peroxidation level twofold.Gibberellins were shown to have a similar effect on permeability of cell membranes for free nucleotides. The permeability of cell membranes in leaves decreased 2.8-fold at room temperature. We suggest that gibberellins

  10. Regeneration systems for pyramiding disease resistance into walnut rootstocks

    Science.gov (United States)

    This study was conducted to regenerate selected walnut rootstocks adventitiously. This is an essential step to be able to produce transgenic walnut rootstocks with superior traits, such as disease resistance. A series of plant tissue culture experiments were conducted on RX1 and VX211 rootstocks wit...

  11. Microbially produced phytotoxins and plant disease management ...

    African Journals Online (AJOL)

    Microbially produced phytotoxins and plant disease management. ... African Journal of Biotechnology ... Pathogenic fungi and bacteria often damage their host (plants) tissues by producing toxic metabolites, which induced various symptoms ...

  12. Transgenic Cotton and Disease Resistance Genes

    Institute of Scientific and Technical Information of China (English)

    RAJASEKARAN; Kanniah

    2008-01-01

    Success in conventional breeding for resistance to mycotoxin-producing or other phytopathogenic fungi is dependent on the availability of resistance gene(s) in the germplasm.Even when it is available,breeding for disease-resistant crops is very time consuming,especially in perennial crops such as

  13. Stochastic spatial models of plant diseases

    CERN Document Server

    Brown, D H

    2001-01-01

    I present three models of plant--pathogen interactions. The models are stochastic and spatially explicit at the scale of individual plants. For each model, I use a version of pair approximation or moment closure along with a separation of timescales argument to determine the effects of spatial clustering on threshold structure. By computing the spatial structure early in an invasion, I find explicit corrections to mean field theory. In the first chapter, I present a lattice model of a disease that is not directly lethal to its host, but affects its ability to compete with neighbors. I use a type of pair approximation to determine conditions for invasions and coexistence. In the second chapter, I study a basic SIR epidemic point process in continuous space. I implement a multiplicative moment closure scheme to compute the threshold transmission rate as a function of spatial parameters. In the final chapter, I model the evolution of pathogen resistance when two plant species share a pathogen. Evolution may lead...

  14. Climate change and plant disease management.

    Science.gov (United States)

    Coakley, S M; Scherm, H; Chakraborty, S

    1999-09-01

    ▪ Abstract  Research on impacts of climate change on plant diseases has been limited, with most work concentrating on the effects of a single atmospheric constituent or meteorological variable on the host, pathogen, or the interaction of the two under controlled conditions. Results indicate that climate change could alter stages and rates of development of the pathogen, modify host resistance, and result in changes in the physiology of host-pathogen interactions. The most likely consequences are shifts in the geographical distribution of host and pathogen and altered crop losses, caused in part by changes in the efficacy of control strategies. Recent developments in experimental and modeling techniques offer considerable promise for developing an improved capability for climate change impact assessment and mitigation. Compared with major technological, environmental, and socioeconomic changes affecting agricultural production during the next century, climate change may be less important; it will, however, add another layer of complexity and uncertainty onto a system that is already exceedingly difficult to manage on a sustainable basis. Intensified research on climate change-related issues could result in improved understanding and management of plant diseases in the face of current and future climate extremes.

  15. 植物抗病WRKY转录因子生物信息学分析%Bioinformatics Analysis of WRKY Transcription Factors with Resistance to Disease in Plant

    Institute of Scientific and Technical Information of China (English)

    路裕; 周振华; 胡尚连; 曹颖; 卢学琴

    2014-01-01

    以GenBank上登录的拟南芥(Arabidopsis thaliana)、欧芹(Petroselinum crispum)、辣椒(Capsicum annuum L.)、水稻(Oryza sativa L.)和毛白杨(Populus tomentosa)的22个WRKY家族抗病转录因子为分析对象,采用生物信息学方法对其系统发生树、保守基序和蛋白质三级结构进行分析。结果表明,22个抗病WRKY转录因子分为2个大类群,7个亚类群。两大类群的转录因子都具有基序1和2,系统发育树中第一大类群中的拟南芥AtWRKY4和AtWRKY25,欧芹PcWRKY1和辣椒CaWRKY-a具有相似的蛋白质三级结构,其都具有基序9和基序12,拟南芥AtWRKY33和AtWRKY48具有相似的蛋白质三级结构,都具有基序18;系统发育树中第四亚类群中的辣椒CaWRKY1和毛白杨PtWRKY23,具有相似的蛋白质三级结构。%The phylogenetic tree and conservative motif and tertiary structure of protein from 22 WRKY transcription factors with resistance to disease were analyzed in Arabidopsis thaliana, Petroselinum crispum, Capsicum annuum L. and Oryza sati-va L., Populus tomentosa, which registered in GenBank by bioinformatics methods. The results showed that 22 WRKY tran-scription factors with resistance to disease were divided into two main groups, seven sub-groups. They had the conservative motif 1 and 2. The tertiary structure of protein encoded by AtWRKY4 and AtWRKY25, PcWRKY1 and CaWRKY-a, be-longed to the first main group, was similar. They had the conservative motif 9 and 12. The tertiary structure of protein en-coded by AtWRKY33 and AtWRKY48, and they had the conservative motif 18. The tertiary structure of protein encoded by CaWRKY1 and PtWRKY23 was similar, and they belonged to the forth sub-group.

  16. Natural disease resistance in threatened staghorn corals.

    Science.gov (United States)

    Vollmer, Steven V; Kline, David I

    2008-01-01

    Disease epidemics have caused extensive damage to tropical coral reefs and to the reef-building corals themselves, yet nothing is known about the abilities of the coral host to resist disease infection. Understanding the potential for natural disease resistance in corals is critically important, especially in the Caribbean where the two ecologically dominant shallow-water corals, Acropora cervicornis and A. palmata, have suffered an unprecedented mass die-off due to White Band Disease (WBD), and are now listed as threatened under the US Threatened Species Act and as critically endangered under the IUCN Red List criteria. Here we examine the potential for natural resistance to WBD in the staghorn coral Acropora cervicornis by combining microsatellite genotype information with in situ transmission assays and field monitoring of WBD on tagged genotypes. We show that six percent of staghorn coral genotypes (3 out of 49) are resistant to WBD. This natural resistance to WBD in staghorn corals represents the first evidence of host disease resistance in scleractinian corals and demonstrates that staghorn corals have an innate ability to resist WBD infection. These resistant staghorn coral genotypes may explain why pockets of Acropora have been able to survive the WBD epidemic. Understanding disease resistance in these corals may be the critical link to restoring populations of these once dominant corals throughout their range.

  17. Natural disease resistance in threatened staghorn corals.

    Directory of Open Access Journals (Sweden)

    Steven V Vollmer

    Full Text Available Disease epidemics have caused extensive damage to tropical coral reefs and to the reef-building corals themselves, yet nothing is known about the abilities of the coral host to resist disease infection. Understanding the potential for natural disease resistance in corals is critically important, especially in the Caribbean where the two ecologically dominant shallow-water corals, Acropora cervicornis and A. palmata, have suffered an unprecedented mass die-off due to White Band Disease (WBD, and are now listed as threatened under the US Threatened Species Act and as critically endangered under the IUCN Red List criteria. Here we examine the potential for natural resistance to WBD in the staghorn coral Acropora cervicornis by combining microsatellite genotype information with in situ transmission assays and field monitoring of WBD on tagged genotypes. We show that six percent of staghorn coral genotypes (3 out of 49 are resistant to WBD. This natural resistance to WBD in staghorn corals represents the first evidence of host disease resistance in scleractinian corals and demonstrates that staghorn corals have an innate ability to resist WBD infection. These resistant staghorn coral genotypes may explain why pockets of Acropora have been able to survive the WBD epidemic. Understanding disease resistance in these corals may be the critical link to restoring populations of these once dominant corals throughout their range.

  18. Mechanisms involved in biocontrol and plant induced resistance by Trichoderna asperellun (T.harzianum T-203)

    Institute of Scientific and Technical Information of China (English)

    Chet I; Shoresh M; Yedidia I; Viterbo A

    2004-01-01

    @@ Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderna spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.

  19. Are Sewage Treatment Plants Promoting Antibiotic Resistance?

    Science.gov (United States)

    1. Introduction 1.1. How bacteria exhibit resistance 1.1.1. Resistance to -lactams 1.1.2. Resistance to sulphonamides and trimethoprim 1.1.3. Resistance to macrolides 1.1.4. Resistance to fluoroquinolones 1.1.5. Resistance to tetracyclines 1.1.6. Resistance to nitroimidaz...

  20. Are Sewage Treatment Plants Promoting Antibiotic Resistance?

    Science.gov (United States)

    1. Introduction 1.1. How bacteria exhibit resistance 1.1.1. Resistance to -lactams 1.1.2. Resistance to sulphonamides and trimethoprim 1.1.3. Resistance to macrolides 1.1.4. Resistance to fluoroquinolones 1.1.5. Resistance to tetracyclines 1.1.6. Resistance to nitroimidaz...

  1. Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants.

    Science.gov (United States)

    Schütte, Gesine; Eckerstorfer, Michael; Rastelli, Valentina; Reichenbecher, Wolfram; Restrepo-Vassalli, Sara; Ruohonen-Lehto, Marja; Saucy, Anne-Gabrielle Wuest; Mertens, Martha

    2017-01-01

    Farmland biodiversity is an important characteristic when assessing sustainability of agricultural practices and is of major international concern. Scientific data indicate that agricultural intensification and pesticide use are among the main drivers of biodiversity loss. The analysed data and experiences do not support statements that herbicide-resistant crops provide consistently better yields than conventional crops or reduce herbicide amounts. They rather show that the adoption of herbicide-resistant crops impacts agronomy, agricultural practice, and weed management and contributes to biodiversity loss in several ways: (i) many studies show that glyphosate-based herbicides, which were commonly regarded as less harmful, are toxic to a range of aquatic organisms and adversely affect the soil and intestinal microflora and plant disease resistance; the increased use of 2,4-D or dicamba, linked to new herbicide-resistant crops, causes special concerns. (ii) The adoption of herbicide-resistant crops has reduced crop rotation and favoured weed management that is solely based on the use of herbicides. (iii) Continuous herbicide resistance cropping and the intensive use of glyphosate over the last 20 years have led to the appearance of at least 34 glyphosate-resistant weed species worldwide. Although recommended for many years, farmers did not counter resistance development in weeds by integrated weed management, but continued to rely on herbicides as sole measure. Despite occurrence of widespread resistance in weeds to other herbicides, industry rather develops transgenic crops with additional herbicide resistance genes. (iv) Agricultural management based on broad-spectrum herbicides as in herbicide-resistant crops further decreases diversity and abundance of wild plants and impacts arthropod fauna and other farmland animals. Taken together, adverse impacts of herbicide-resistant crops on biodiversity, when widely adopted, should be expected and are indeed very hard

  2. Radiation therapy for resistant sternal hydatid disease

    Energy Technology Data Exchange (ETDEWEB)

    Ulger, S.; Barut, H.; Tunc, M.; Aydinkarahaliloglu, E. [Ataturk Chest Disease and Thorasic Surgery Training and Research Hospital, Ankara (Turkey). Dept. of Radiation Oncology; Aydin, E.; Karaoglanoglu, N. [Ataturk Chest Disease and Thorasic Surgery Training and Research Hospital, Ankara (Turkey). Dept. of Thorasic Surgery; Gokcek, A. [Ataturk Chest Disease and Thorasic Surgery Training and Research Hospital, Ankara (Turkey). Dept. of Radiology

    2013-06-15

    Hydatid disease is a zoonotic infectious disease for which there are known treatment procedures and effective antibiotics; however, there are resistant cases that do not respond to medication or surgery. We report a case diagnosed as hydatid disease of the chest wall and treated with radiation therapy (RT) after medical and surgical therapy had failed. In conclusion, RT represents an alternative treatment modality in resistant cases. (orig.)

  3. The biochar effect: plant resistance to biotic stresses

    Directory of Open Access Journals (Sweden)

    YIGAL ELAD

    2012-01-01

    Full Text Available Biochar (charcoal is the solid co-product of pyrolysis, the thermal degradation of biomass in the absence of oxygen. Pyrolysis also yields gaseous and liquid biofuel products. There is a growing interest worldwide in the pyrolysis platform, for at least four reasons: (i pyrolysis can be a source of renewable biofuels; (ii many biomass waste materials can be treated by pyrolysis and thus converted into a fuel resource; (iii long-term sequestration of carbon dioxide which originated in the atmosphere may result from adding biochar to soil; and (iv biochar soil amendment contributes to improved soil fertility and crop productivity. Currently, however, very little biochar is utilized in agriculture, in part because its agronomic value in terms of crop response and soil health benefits have yet to be quantified, and because the mechanisms by which it improves soil fertility are poorly understood. The positive effects of biochar on crop productivity under conditions of extensive agriculture are frequently attributed to direct effects of biochar-supplied nutrients and to several other indirect effects, including increased water and nutrient retention, improvements in soil pH, increased soil cation exchange capacity, effects on P and S transformations and turnover, neutralization of phytotoxic compounds in the soil, improved soil physical properties, promotion of mycorrhizal fungi, and alteration of soil microbial populations and functions. Yet, the biochar effect is also evident under conditions of intensive production where many of these parameters are not limited. Biochar addition to soil alters microbial populations in the rhizosphere, albeit via mechanisms not yet understood, and may cause a shift towards beneficial microorganism populations that promote plant growth and resistance to biotic stresses. In addition to some scant evidence for biochar-induced plant protection against soilborne diseases, the induction of systemic resistance towards

  4. aiiA基因在植物软腐病研究中的应用进展%Progress on Applying aiiA Gene in Plant Resistance to Soft Rot Disease

    Institute of Scientific and Technical Information of China (English)

    韩丽伟; 屈淑平; 崔崇士

    2011-01-01

    N-acyl-homoserine lactones (AHLs) are signal molecules in many gram-negative bacterias' quorum sensing, called Autoinducer ( AI ). AiiA protein encoded by aiiA gene is involved in the degradation of AHLs, interfering the regulation process of bacterial quorum-sensing, restraining the induced expression of plant soft rot disease genes, and decreasing the virulence of bacterial pathogens.The essay summarizes the research situations of aiiA and AiiA, and the current application situations of aiiA in soft rot-resistant engineering bacteria and transgenic plant. The research directions are pointed out on the effective expression of AiiA proteins and improving plants' soft rot-resistance.%N-酰基高丝氨酸内酯(N-acyl-homoserine lactones,AHLs)是一类广泛存在于许多革兰氏阴性细菌群体感应系统中的信号分子,又称作自体诱导物(Autoinducer,AI).aiiA基因编码的AiiA蛋白能降解细菌产生的AHLs信号分子,干扰该信号分子参与细菌群体感应的调控过程,抑制多种植物病原菌致病基因的诱导表达,从而减轻或消除病原菌的致病性.本文介绍了aiiA基因、AiiA蛋白的研究情况,以及aiiA基因在抗软腐病工程菌和转基因植物研究上的应用现状,并提出了提高植物抗软腐病的研究方向.

  5. Host plant resistance to parasitic weeds; recent progress and bottlenecks.

    Science.gov (United States)

    Yoder, John I; Scholes, Julie D

    2010-08-01

    Parasitic witchweeds (Striga spp.) and broomrapes (Orobanche and Phelipanche spp.) directly invade the roots of crop plants connecting to the vascular system and abstracting nutrients and water. As a consequence they cause devastating losses in crop yield. Genetic resistance to parasitic weeds is a highly desirable component of any control strategy. Resistance to parasitic plants can occur at different stages of the parasite lifecycle: before attachment to the host, during penetration of the root or after establishment of vascular connections. New studies are beginning to shed light on the molecular mechanisms and signaling pathways involved in plant-plant resistance. The first resistance gene to Striga, encoding a CC-NBS-LRR Resistance protein (R) has been identified and cloned suggesting that host plants resist attack from parasitic plants using similar surveillance mechanisms as those used against fungal and bacterial pathogens. It is becoming clear that the salicylic acid (SA) signaling pathway plays an important role in resistance to parasitic plants and genes encoding pathogenesis-related (PR) proteins are upregulated in a number of the resistant interactions. New strategies for engineering resistance to parasitic plants are also being explored, including the expression of parasite-specific toxins in host roots and RNAi to silence parasite genes crucial for development.

  6. Deciphering plant-pathogen communication: fresh perspectives for molecular resistance breeding.

    Science.gov (United States)

    Hammond-Kosack, Kim E; Parker, Jane E

    2003-04-01

    Activation of local and systemic plant defences in response to pathogen attack involves dramatic cellular reprogramming. Over the past 10 years many novel genes, proteins and molecules have been discovered as a result of investigating plant-pathogen interactions. Most attempts to harness this knowledge to engineer improved disease resistance in crops have failed. Although gene efficacy in transgenic plants has often been good, commercial exploitation has not been possible because of the detrimental effects on plant growth, development and crop yield. Biotechnology approaches have now shifted emphasis towards marker-assisted breeding and the construction of vectors containing highly regulated transgenes that confer resistance in several distinct ways.

  7. Transgenic Cotton and Disease Resistance Genes

    Institute of Scientific and Technical Information of China (English)

    RAJASEKARAN Kanniah

    2008-01-01

    @@ Success in conventional breeding for resistance to mycotoxin-producing or other phytopathogenic fungi is dependent on the availability of resistance gene(s) in the germplasm.Even when it is available,breeding for disease-resistant crops is very time consuming,especially in perennial crops such as tree nut crops,and does not lend itself ready to combat the evolution of new virulent fungal races.

  8. Climate change: potential impact on plant diseases.

    Science.gov (United States)

    Chakraborty, S; Tiedemann, A V; Teng, P S

    2000-06-01

    Global climate has changed since pre-industrial times. Atmospheric CO(2), a major greenhouse gas, has increased by nearly 30% and temperature has risen by 0.3 to 0.6 degrees C. The intergovernmental panel on climate change predicts that with the current emission scenario, global mean temperature would rise between 0.9 and 3.5 degrees C by the year 2100. There are, however, many uncertainties that influence these predictions. Despite the significance of weather on plant diseases, comprehensive analysis of how climate change will influence plant diseases that impact primary production in agricultural systems is presently unavailable. Evaluation of the limited literature in this area suggests that the most likely impact of climate change will be felt in three areas: in losses from plant diseases, in the efficacy of disease management strategies and in the geographical distribution of plant diseases. Climate change could have positive, negative or no impact on individual plant diseases. More research is needed to obtain base-line information on different disease systems. Most plant disease models use different climatic variables and operate at a different spatial and temporal scale than do the global climate models. Improvements in methodology are necessary to realistically assess disease impacts at a global scale.

  9. Insulin resistance and cardiovascular disease.

    Science.gov (United States)

    Egan, B M; Greene, E L; Goodfriend, T L

    2001-06-01

    Cardiovascular risk factors cluster in obese individuals. Insulin resistance emerges as a common pathogenetic denominator underlying the risk factor cluster. Defects in nonesterified fatty acids metabolism have been implicated in the abnormal lipid and glucose metabolism which characterize the cluster. Other evidence also leads to the adipocyte as an important contributor to the risk factor cluster and cardiovascular complications through effects not only on fatty acids but also on leptin, plasminogen activator inhibitor-1, and angiotensinogen, to name a few. Fatty acids are elevated among abdominally obese individuals, are more resistant to suppression by insulin, and may contribute to hypertension. Fatty acids may affect blood pressure by inhibiting endothelial nitric oxide synthase activity and impairing endothelium-dependent vasodilation. Fatty acids increase alpha1-adrenoceptor-mediated vascular reactivity and enhance the proliferation and migration of cultured vascular smooth-muscle cells. Several effects of fatty acids are mediated through oxidative stress. Fatty acids can also interact with other facets of cluster, including increased angiotensin II, to accentuate oxidative stress. Oxidative stress, in turn, is implicated in the pathogenesis of insulin resistance, hypertension, vascular remodeling, and vascular complications. A clearer delineation of the key reactive oxygen signaling pathways and the impact of various interventions on these pathways could facilitate a rationale approach to antioxidant therapy and improved outcomes among the rapidly growing number of high-risk, insulin-resistant, obese individuals.

  10. A meta-analysis of genetic correlations between plant resistances to multiple enemies.

    Science.gov (United States)

    Leimu, Roosa; Koricheva, Julia

    2006-07-01

    Genetic correlations between plant resistances to multiple natural enemies are important because they have the potential to determine the mode of selection that natural enemies impose on a host plant, the structure of herbivore and pathogen communities, and the success of plant breeding for resistance to multiple diseases and pests. We conducted a meta-analysis of 29 published studies of 16 different plant species reporting a total of 467 genetic correlations between resistances to multiple herbivores or pathogens. In general, genetic associations between resistances to multiple natural enemies tended to be positive regardless of the breeding design, type of attacker, and type of host plant. Positive genetic correlations between resistances were stronger when both attackers were pathogens or generalist herbivores and when resistance to different enemies was tested independently, suggesting that generalists may be affected by the same plant resistance traits and that interactions among natural enemies are common. Although the mean associations between resistances were positive, indicating the prevalence of diffuse selection and generalized defenses against multiple enemies, the large variation in both the strength and the direction of the associations suggests a continuum between pairwise and diffuse selection.

  11. Characterization of partial resistance to black spot disease of Rosa spp.

    Science.gov (United States)

    Black spot disease (BSD) is one of the most serious diseases of garden roses. Both complete (vertical) resistance and partial (horizontal) resistance have been identified in 16 rose genotypes using two laboratory assays, the detached leaf assay (DLA) and the whole plant inoculation (WPI) approaches...

  12. Cladosporium fulvum CfHNNI1 induces hypersensitive necrosis, defence gene expression and disease resistance in both host and nonhost plants

    NARCIS (Netherlands)

    Cai, X.Z.; Zhou, X.; Xu, Y.P.; Joosten, M.H.A.J.; Wit, de P.J.G.M.

    2007-01-01

    Nonhost resistance as a durable and broad-spectrum defence strategy is of great potential for agricultural applications. We have previously isolated a cDNA showing homology with genes encoding bZIP transcription factors from tomato leaf mould pathogen Cladosporium fulvum. Upon expression, the cDNA r

  13. Cladosporium fulvum CfHNNI1 induces hypersensitive necrosis, defence gene expression and disease resistance in both host and nonhost plants

    NARCIS (Netherlands)

    Cai, X.Z.; Zhou, X.; Xu, Y.P.; Joosten, M.H.A.J.; Wit, de P.J.G.M.

    2007-01-01

    Nonhost resistance as a durable and broad-spectrum defence strategy is of great potential for agricultural applications. We have previously isolated a cDNA showing homology with genes encoding bZIP transcription factors from tomato leaf mould pathogen Cladosporium fulvum. Upon expression, the cDNA

  14. Transgenic Strategies for Enhancement of Nematode Resistance in Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-05-01

    Full Text Available Plant parasitic nematodes (PPNs are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

  15. Transgenic Strategies for Enhancement of Nematode Resistance in Plants.

    Science.gov (United States)

    Ali, Muhammad A; Azeem, Farrukh; Abbas, Amjad; Joyia, Faiz A; Li, Hongjie; Dababat, Abdelfattah A

    2017-01-01

    Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

  16. Induced systemic resistance by plant growth-promoting rhizobacteria

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Pelt, J.A. van; Verhagen, B.W.M.; Ton, J.; Wees, A.C.M. van; Léon-Kloosterziel, K.M.; Loon, L.C. van

    2003-01-01

    Rhizobacteria are present in large numbers on the root surface, where plant exudates and lysates provide nutrients. Selected strains of beneficial, plant growth-promoting rhizobacteria (PGPR) trigger a plant-mediated induced systemic resistance (ISR) response that is effective against a broad spectr

  17. A novel approach for multi-domain and multi-gene famliy identification provides insights into evolutionary dynamics of disease resistance genes in core eudicot plants

    NARCIS (Netherlands)

    Hofberger, J.A.; Zhou, B.; Tang, H.; Jones, J.; Schranz, M.E.

    2014-01-01

    Background Recent advances in DNA sequencing techniques resulted in more than forty sequenced plant genomes representing a diverse set of taxa of agricultural, energy, medicinal and ecological importance. However, gene family curation is often only inferred from DNA sequence homology and lacks

  18. Bipolar resistive switching in different plant and animal proteins

    KAUST Repository

    Bag, A.

    2014-06-01

    We report bipolar resistive switching phenomena observed in different types of plant and animal proteins. Using protein as the switching medium, resistive switching devices have been fabricated with conducting indium tin oxide (ITO) and Al as bottom and top electrodes, respectively. A clockwise bipolar resistive switching phenomenon is observed in all proteins. It is shown that the resistive switching phenomena originate from the local redox process in the protein and the ion exchange from the top electrode/protein interface.

  19. Application of next-generation sequencing for rapid marker development in molecular plant breeding: a case study on anthracnose disease resistance in Lupinus angustifolius L.

    OpenAIRE

    2012-01-01

    Abstract Background In the last 30 years, a number of DNA fingerprinting methods such as RFLP, RAPD, AFLP, SSR, DArT, have been extensively used in marker development for molecular plant breeding. However, it remains a daunting task to identify highly polymorphic and closely linked molecular markers for a target trait for molecular marker-assisted selection. The next-generation sequencing (NGS) technology is far more powerful than any existing generic DNA fingerprinting methods in generating ...

  20. Genetically engineered virus-resistant plants in developing countries: current status and future prospects.

    Science.gov (United States)

    Reddy, D V R; Sudarshana, M R; Fuchs, M; Rao, N C; Thottappilly, G

    2009-01-01

    Plant viruses cause severe crop losses worldwide. Conventional control strategies, such as cultural methods and biocide applications against arthropod, nematode, and plasmodiophorid vectors, have limited success at mitigating the impact of plant viruses. Planting resistant cultivars is the most effective and economical way to control plant virus diseases. Natural sources of resistance have been exploited extensively to develop virus-resistant plants by conventional breeding. Non-conventional methods have also been used successfully to confer virus resistance by transferring primarily virus-derived genes, including viral coat protein, replicase, movement protein, defective interfering RNA, non-coding RNA sequences, and protease, into susceptible plants. Non-viral genes (R genes, microRNAs, ribosome-inactivating proteins, protease inhibitors, dsRNAse, RNA modifying enzymes, and scFvs) have also been used successfully to engineer resistance to viruses in plants. Very few genetically engineered (GE) virus resistant (VR) crops have been released for cultivation and none is available yet in developing countries. However, a number of economically important GEVR crops, transformed with viral genes are of great interest in developing countries. The major issues confronting the production and deregulation of GEVR crops in developing countries are primarily socio-economic and related to intellectual property rights, biosafety regulatory frameworks, expenditure to generate GE crops and opposition by non-governmental activists. Suggestions for satisfactory resolution of these factors, presumably leading to field tests and deregulation of GEVR crops in developing countries, are given.

  1. Seleção do algodoeiro para resistência à fusariose em área onde ocorre doença semelhante em plantas de labelabe (Dolichos lablab L. Selection of cotton plants resistant to fusarium wilt in a plot where similar disease occurs on hyacinth bean (Dolichos lablab L.

    Directory of Open Access Journals (Sweden)

    Imre L. Gridi-Papp

    1970-01-01

    Full Text Available Em área de Latossolo Roxo, localizada na Estação Experimental "Theodureto de Camargo", em Campinas, verificou-se incidência de doença provocando "murcha", com sintomas internos caracterizados pelo escurecimento dos vasos, sucessivamente em plantas de labelabe e em algodoeiro. Em ambas as espécies vegetais determinou-se a presença de fungos do gênero Fusarium, mediante isolamento feito em plantas doentes. Seleções, feitas na referida área, de plantas pertencentes a linhagem de algodoeiro suscetível à murcha de Fusariumderam origem a linhagens que revelaram apreciável resistência quando testadas em solo infestado por Fusarium oxysporum f.vasinfectum (Atk. Snyder & Hansen. São discutidos aspectos relacionados com a possível descoberta de nova fonte genética de resistência à doença e com a existência desse fungo sob infestação natural na Estação Experimental mencionada. Também é apontada a possibilidade de serem o algodoeiro e a leguminosa em questão hospedeiras do mesmo agente patogênico.The occurrence of wilt disease, successively in plants of hyacinth bean (Dolichos lablab L. and cotton, was observed in a plot of latosolic B (Terra Roxa soil at the "Theodureto de Camargo" Experiment Station at Campinas, where no Fusarium wilt has been recorded before. Both species presented internal symptoms consisting in darkened vessels. Fungi of the genus Fusarium were isolated from these plants. Plant selection for wilt resistance was made in the above mentioned area where a Fusarium - susceptible variety (IAG 51/1104 of cotton had been planted. The progenies when tested in soils infested by Fusarium oxysporum f. vasinfectum Atk. Snyder & Hansen revealed fair resistance to wilt. IAG 51/1104 comes from a cross between the varieties Delfos and Delta Pineland-10, both wilt susceptible under field conditions of the State of São Paulo. It is likely that the wilt resistance of some of its progeny might have originated by recombination

  2. [The problem of durable resistance of plants to different pests].

    Science.gov (United States)

    Odintsova, I G; Radchenko, E E; Tyryshkin, L G

    2002-01-01

    Different hypotheses concerning durable plant resistance against different pest were tested: 1) resistance is weak and polygenetically controlled; 2) resistance depends on "residual effect" of oligogenes that were overcome by pests. Contrast pair of plants and pests were used in experiments: wheat, barley--facultative parasite Bipolaris sorokiniana Shoem., wheat--obligate parasite Puccinia recondita Rob. ex Desm., sorghum--greenbug Schizaphis graminum Rond. Differential interaction between parasite and host plant resulted in their increased compatibility under long reproduction of parasite on resistant varieties were regarded as criteria of quick overcoming of resistance. The results did not support any hypothesis. The rate of adaptation of B. sorokiniana to the resistant varieties of wheat and barley did not depend on the level of resistance expression (weak, moderate or strong) and genetic control (oligogenic, polygenic or cytoplasmatic). It was shown by hybridological analysis that "residual effect" of oligogenes of sorghum resistance against greenbug depended on small resistance genes, that can be independent or weakly connected with marker oligogene. These data allows to doubt in phenomenon of "residual effect" of oligogenes. It was shown that non specific pathogenicity of parasitic fungi increased during their reproductions on sensitive varieties of plants. Thus, cultivation of sensitive varieties causes damage of crop culture non only because of their own losses, but also by increasing the infection of moderately resistant varieties.

  3. Northwest forest plants defeat pests and diseases!

    Science.gov (United States)

    Natasha Vizcarra; Rick Kelsey; Joe. Karchesy

    2017-01-01

    Societies use biologically active chemicals as medicines and pesticides to protect human and agricultural health. But widespread use of synthetic compounds raises concerns about their safety, and resistance development in targeted pests.To find safer alternatives, scientists turned to native plants and trees in Pacific Northwest forests...

  4. Thirteen challenges in modelling plant diseases

    Science.gov (United States)

    The underlying structure of epidemiological models, and the questions that models can be used to address, do not necessarily depend on the identity of the host. This means that certain preoccupations of plant disease modelers are similar to those of modelers of diseases in animals and humans. Howeve...

  5. NOTE - Minimum number of common bean plants per plot to assess field resistance to white mold

    Directory of Open Access Journals (Sweden)

    uliana Andrade Dias

    2011-01-01

    Full Text Available This study aimed to determine the minimum number of plants per plot to assess the field resistance in common beanto white mold. Thirteen cultivars were inoculated with six isolates of Sclerotinia sclerotiorum and evaluated in a randomized blockdesign with three replications and plots consisting of 1-m rows with 15 plants. Plants were inoculated by the straw test as proposedby Petzoldt and Dickson (1996, to evaluate partial resistance in a greenhouse. Eight days after inoculation the disease severity wasevaluated on a 1-9 diagrammatic scale, where 1 = asymptomatic plants to 9 = plant death. To determine the minimum number ofplants per plot, the following methods were used: maximum curvature, segmented linear model, quadratic segmented model and therelative CV model. There were significant differences among cultivars and isolates and no significant cultivar - isolate interaction.It was observed that eight plants per plot is an adequate number to assess the reaction of common bean to white mold.

  6. Fitness costs associated with evolved herbicide resistance alleles in plants.

    Science.gov (United States)

    Vila-Aiub, Martin M; Neve, Paul; Powles, Stephen B

    2009-12-01

    Predictions based on evolutionary theory suggest that the adaptive value of evolved herbicide resistance alleles may be compromised by the existence of fitness costs. There have been many studies quantifying the fitness costs associated with novel herbicide resistance alleles, reflecting the importance of fitness costs in determining the evolutionary dynamics of resistance. However, many of these studies have incorrectly defined resistance or used inappropriate plant material and methods to measure fitness. This review has two major objectives. First, to propose a methodological framework that establishes experimental criteria to unequivocally evaluate fitness costs. Second, to present a comprehensive analysis of the literature on fitness costs associated with herbicide resistance alleles. This analysis reveals unquestionable evidence that some herbicide resistance alleles are associated with pleiotropic effects that result in plant fitness costs. Observed costs are evident from herbicide resistance-endowing amino acid substitutions in proteins involved in amino acid, fatty acid, auxin and cellulose biosynthesis, as well as enzymes involved in herbicide metabolism. However, these resistance fitness costs are not universal and their expression depends on particular plant alleles and mutations. The findings of this review are discussed within the context of the plant defence trade-off theory and herbicide resistance evolution.

  7. Bespoke microbiome therapy to manage plant diseases

    Directory of Open Access Journals (Sweden)

    Murali eGopal

    2013-12-01

    Full Text Available Advanced biological technologies are revealing that the microbiome, located in gut and rhizosphere, is responsible for maintaining the health of human beings and plants, respectively. Within the complete microbiome a ‘core-microbiome’ exists that plays the pivotal role. Recent studies in medicine have shown that an artificial mixture of bacteria representing the core gut microbiome of healthy person when transferred into gut of diseased person results in re-establishment of normal microflora in the latter leading to alleviation from diseased condition. In agriculture, plant disease management has been achieved through transfer of microbiome by mixing disease suppressive soils with disease conducive soils. However, the exact practice of transferring artificially cultivated core-microbiome as in medicine has not thus far been attempted in plant disease management. Nonetheless, as the gut and rhizosphere microbiome are known to share many common traits, there exists a good scope for accomplishing similar studies in agriculture. Based upon the information in microbiome studies of gut and rhizosphere, we propose that tailor-made core-microbiome transfer therapy can become a viable strategy for management of plant diseases in future.

  8. Role of the plant cell wall in gravity resistance.

    Science.gov (United States)

    Hoson, Takayuki; Wakabayashi, Kazuyuki

    2015-04-01

    Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, comparable to gravitropism. The cell wall is responsible for the final step of gravity resistance. The gravity signal increases the rigidity of the cell wall via the accumulation of its constituents, polymerization of certain matrix polysaccharides due to the suppression of breakdown, stimulation of cross-link formation, and modifications to the wall environment, in a wide range of situations from microgravity in space to hypergravity. Plants thus develop a tough body to resist the gravitational force via an increase in cell wall rigidity and the modification of growth anisotropy. The development of gravity resistance mechanisms has played an important role in the acquisition of responses to various mechanical stresses and the evolution of land plants.

  9. Unmasking levodopa resistance in Parkinson's disease.

    Science.gov (United States)

    Nonnekes, Jorik; Timmer, Monique H M; de Vries, Nienke M; Rascol, Olivier; Helmich, Rick C; Bloem, Bastiaan R

    2016-11-01

    Some motor and nonmotor features associated with Parkinson's disease (PD) do not seem to respond well to levodopa (or other forms of dopaminergic medication) or appear to become resistant to levodopa treatment with disease progression and longer disease duration. In this narrative review, we elaborate on this issue of levodopa resistance in PD. First, we discuss the possibility of pseudoresistance, which refers to dopamine-sensitive symptoms or signs that falsely appear to be (or have become) resistant to levodopa, when in fact other mechanisms are at play, resulting in suboptimal dopaminergic efficacy. Examples include interindividual differences in pharmacodynamics and pharmacokinetics and underdosing because of dose-limiting side effects or because of levodopa phobia. Moreover, pseudoresistance can emerge as not all features of PD respond adequately to the same dosage of levodopa. Second, we address that for several motor features (eg, freezing of gait or tremor) and several nonmotor features (eg, specific cognitive functions), the response to levodopa is fairly complex, with a combination of levodopa-responsive, levodopa-resistant, and even levodopa-induced characteristics. A possible explanation relates to the mixed presence of underlying dopaminergic and nondopaminergic brain lesions. We suggest that clinicians take these possibilities into account before concluding that symptoms or signs of PD are totally levodopa resistant. © 2016 International Parkinson and Movement Disorder Society.

  10. Study of the induced systemic resistance of plants: molecular aspects of the interaction between plant cells and amphiphilic elicitors produced by non-pathogenic rhizobacteria

    OpenAIRE

    Henry, Guillaume

    2013-01-01

    Some non pathogenic rhizobacteria could locally interact with plants, leading to the stimulation of a primed protection state in the host plant. Upon subsequent pathogen attack, this priming state allows an accelerated activation of defense responses extending to all organs of the plant. Fundamental as well as applied research about this induced systemic resistance (ISR) has been tremendously boosted in the past decades, driven by its evident potential for biological control of plant diseases...

  11. Editing plants for virus resistance using CRISPR-Cas.

    Science.gov (United States)

    Green, J C; Hu, J S

    This minireview summarizes recent advancements using the clustered regularly interspaced palindromic repeats-associated nuclease systems (CRISPR-Cas) derived from prokaryotes to breed plants resistant to DNA and RNA viruses. The CRISPR-Cas system represents a powerful tool able to edit and insert novel traits into plants precisely at chosen loci offering enormous advantages to classical breeding. Approaches to engineering plant virus resistance in both transgenic and non-transgenic plants are discussed. Iterations of the CRISPR-Cas system, FnCas9 and C2c2 capable of editing RNA in eukaryotic cells offer a particular advantage for providing resistance to RNA viruses which represent the great majority of known plant viruses. Scientists have obtained conflicting results using gene silencing technology to produce transgenic plants resistant to geminiviruses. CRISPR-Cas systems engineered in plants to target geminiviruses have consistently reduced virus accumulation providing increased resistance to virus infection. CRISPR-Cas may provide novel and reliable approaches to control geminiviruses and other ssDNA viruses such as Banana bunchy top virus (BBTV).

  12. Characterization of glyphosate resistance in cloned Amaranthus palmeri plants

    Science.gov (United States)

    Glyphosate resistant Palmer amaranth from Georgia (GA) possesses multiple copies of the target site, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) of this herbicide. Cloned plants of glyphosate-resistant Palmer amaranth biotypes from Mississippi (MS) were compared with GA populations using le...

  13. Selection of tomato plants resistant to a local Polish isolate of tomato spotted wilt virus (TSWV).

    Science.gov (United States)

    Czech, Andrzej S; Szklarczyk, Marek; Gajewski, Zbigniew; Zukowska, Ewa; Michalik, Barbara; Kobyłko, Tadeusz; Strzałka, Kazimierz

    2003-01-01

    We found that the Sw-5 gene confers resistance to one of the Polish isolates of tomato spotted wilt virus (TSWV). A series of tomato breeding accessions was analysed along with standards of resistance and susceptibility to TSWV. The presence of the Sw-5 gene was determined using the available PCR marker. Subsequently plants from these accessions were grown in the presence of the TSWV isolate from Poland. Some of them developed severe symptoms of the TSWV disease. Expression of the virus proteins was also assayed in tissues of the investigated plants. We found general agreement between either lack or presence of the disease symptoms, virus proteins and resistance gene. Some observed discrepancies of these data are also discussed. Our results indicate that marker-assisted selection can be used for breeding of the TSWV-resistant tomato in Poland.

  14. Enhanced methanol production in plants provides broad spectrum insect resistance.

    Directory of Open Access Journals (Sweden)

    Sameer Dixit

    Full Text Available Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR and spectra showed up to 16 fold higher methanol as compared to control wild type (WT plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid and Bemisia tabaci (whitefly, respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.

  15. Metal resistant plants and phytoremediation of environmental contamination

    Science.gov (United States)

    Meagher, Richard B.; Li, Yujing; Dhankher, Om P.

    2010-04-20

    The present disclosure provides a method of producing transgenic plants which are resistant to at least one metal ion by transforming the plant with a recombinant DNA comprising a nucleic acid encoding a bacterial arsenic reductase under the control of a plant expressible promoter, and a nucleic acid encoding a nucleotide sequence encoding a phytochelatin biosynthetic enzyme under the control of a plant expressible promoter. The invention also relates a method of phytoremediation of a contaminated site by growing in the site a transgenic plant expressing a nucleic acid encoding a bacterial arsenate reductase and a nucleic acid encoding a phytochelatin biosynthetic enzyme.

  16. Herbal plants and plant preparations as remedial approach for viral diseases.

    Science.gov (United States)

    Ganjhu, Rajesh Kumar; Mudgal, Piya Paul; Maity, Hindol; Dowarha, Deepu; Devadiga, Santhosha; Nag, Snehlata; Arunkumar, Govindakarnavar

    2015-12-01

    Herbal plants, plant preparations and phytoconstituents have proved useful in attenuating infectious conditions and were the only remedies available, till the advent of antibiotics (many being of plant origin themselves). Among infectious diseases, viral diseases in particular, remain the leading cause of death in humans globally. A variety of phytoconstituents derived from medicinal herbs have been extensively studied for antiviral activity. Based on this rationale, an online search was performed, which helped to identify a large number of plant species harboring antiviral molecules. These herbal sources have been reported individually or in combinations across a large number of citations studied. Activities against rabies virus, Human immunodeficiency virus, Chandipura virus, Japanese Encephalitis Virus, Enterovirus, Influenza A/H1N1 and other influenza viruses were discovered during the literature search. This review includes all such plant species exhibiting antiviral properties. The review also encompasses composition and methodologies of preparing various antiviral formulations around the globe. An elaborate section on the formulations filed for patent registration, along with non-patented formulations, has also been included in this article. To conclude, herbal sources provide researchers enormous scope to explore and bring out viable alternatives against viral diseases, considering non-availability of suitable drug candidates and increasing resistance to existing drug molecules for many emerging and re-emerging viral diseases.

  17. Transcriptome Analysis of an Anthracnose-Resistant Tea Plant Cultivar Reveals Genes Associated with Resistance to Colletotrichum camelliae.

    Science.gov (United States)

    Wang, Lu; Wang, Yuchun; Cao, Hongli; Hao, Xinyuan; Zeng, Jianming; Yang, Yajun; Wang, Xinchao

    2016-01-01

    Tea plant breeding is a topic of great economic importance. However, disease remains a major cause of yield and quality losses. In this study, an anthracnose-resistant cultivar, ZC108, was developed. An infection assay revealed different responses to Colletotrichum sp. infection between ZC108 and its parent cultivar LJ43. ZC108 had greater resistance than LJ43 to Colletotrichum camelliae. Additionally, ZC108 exhibited earlier sprouting in the spring, as well as different leaf shape and plant architecture. Microarray data revealed that the genes that are differentially expressed between LJ43 and ZC108 mapped to secondary metabolism-related pathways, including phenylpropanoid biosynthesis, phenylalanine metabolism, and flavonoid biosynthesis pathways. In addition, genes involved in plant hormone biosynthesis and signaling as well as plant-pathogen interaction pathways were also changed. Quantitative real-time PCR was used to examine the expression of 27 selected genes in infected and uninfected tea plant leaves. Genes encoding a MADS-box transcription factor, NBS-LRR disease-resistance protein, and phenylpropanoid metabolism pathway components (CAD, CCR, POD, beta-glucosidase, ALDH and PAL) were among those differentially expressed in ZC108.

  18. Controversy Associated With the Common Component of Most Transgenic Plants – Kanamycin Resistance Marker Gene

    OpenAIRE

    Jelenić, Srećko

    2003-01-01

    Plant genetic engineering is a powerful tool for producing crops resistant to pests, diseases and abiotic stress or crops with improved nutritional value or better quality products. Currently over 70 genetically modified (GM) crops have been approved for use in different countries. These cover a wide range of plant species with significant number of different modified traits. However, beside the technology used for their improvement, the common component of most GM crops is the neomycin phosp...

  19. Mycorrhiza-induced resistance and priming of plant defenses.

    Science.gov (United States)

    Jung, Sabine C; Martinez-Medina, Ainhoa; Lopez-Raez, Juan A; Pozo, Maria J

    2012-06-01

    Symbioses between plants and beneficial soil microorganisms like arbuscular-mycorrhizal fungi (AMF) are known to promote plant growth and help plants to cope with biotic and abiotic stresses. Profound physiological changes take place in the host plant upon root colonization by AMF affecting the interactions with a wide range of organisms below- and above-ground. Protective effects of the symbiosis against pathogens, pests, and parasitic plants have been described for many plant species, including agriculturally important crop varieties. Besides mechanisms such as improved plant nutrition and competition, experimental evidence supports a major role of plant defenses in the observed protection. During mycorrhiza establishment, modulation of plant defense responses occurs thus achieving a functional symbiosis. As a consequence of this modulation, a mild, but effective activation of the plant immune responses seems to occur, not only locally but also systemically. This activation leads to a primed state of the plant that allows a more efficient activation of defense mechanisms in response to attack by potential enemies. Here, we give an overview of the impact on interactions between mycorrhizal plants and pathogens, herbivores, and parasitic plants, and we summarize the current knowledge of the underlying mechanisms. We focus on the priming of jasmonate-regulated plant defense mechanisms that play a central role in the induction of resistance by arbuscular mycorrhizas.

  20. Overexpression of the Synthetic Chimeric Native-T-phylloplanin-GFP Genes Optimized for Monocot and Dicot Plants Renders Enhanced Resistance to Blue Mold Disease in Tobacco (N. tabacum L.

    Directory of Open Access Journals (Sweden)

    Dipak K. Sahoo

    2014-01-01

    Full Text Available To enhance the natural plant resistance and to evaluate the antimicrobial properties of phylloplanin against blue mold, we have expressed a synthetic chimeric native-phylloplanin-GFP protein fusion in transgenic Nicotiana tabacum cv. KY14, a cultivar that is highly susceptible to infection by Peronospora tabacina. The coding sequence of the tobacco phylloplanin gene along with its native signal peptide was fused with GFP at the carboxy terminus. The synthetic chimeric gene (native-phylloplanin-GFP was placed between the modified Mirabilis mosaic virus full-length transcript promoter with duplicated enhancer domains and the terminator sequence from the rbcSE9 gene. The chimeric gene, expressed in transgenic tobacco, was stably inherited in successive plant generations as shown by molecular characterization, GFP quantification, and confocal fluorescent microscopy. Transgenic plants were morphologically similar to wild-type plants and showed no deleterious effects due to transgene expression. Blue mold-sensitivity assays of tobacco lines were performed by applying P. tabacina sporangia to the upper leaf surface. Transgenic lines expressing the fused synthetic native-phyllopanin-GFP gene in the leaf apoplast showed resistance to infection. Our results demonstrate that in vivo expression of a synthetic fused native-phylloplanin-GFP gene in plants can potentially achieve natural protection against microbial plant pathogens, including P. tabacina in tobacco.

  1. Identification of QTL for adult plant resistance to stripe rust in Chinese wheat landrace Caoxuan 5

    Science.gov (United States)

    Yellow (or stripe) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an important wheat disease worldwide. The development of wheat cultivars with adult plant resistance (APR) has been given increasing emphasis in recent years because of the reputed durability of APR compared to all-stag...

  2. Obesity, insulin resistance, and cardiovascular disease.

    Science.gov (United States)

    Reaven, Gerald; Abbasi, Fahim; McLaughlin, Tracey

    2004-01-01

    The ability of insulin to stimulate glucose disposal varies more than six-fold in apparently healthy individuals. The one third of the population that is most insulin resistant is at greatly increased risk to develop cardiovascular disease (CVD), type 2 diabetes, hypertension, stroke, nonalcoholic fatty liver disease, polycystic ovary disease, and certain forms of cancer. Between 25-35% of the variability in insulin action is related to being overweight. The importance of the adverse effects of excess adiposity is apparent in light of the evidence that more than half of the adult population in the United States is classified as being overweight/obese, as defined by a body mass index greater than 25.0 kg/m(2). The current epidemic of overweight/obesity is most-likely related to a combination of increased caloric intake and decreased energy expenditure. In either instance, the fact that CVD risk is increased as individuals gain weight emphasizes the gravity of the health care dilemma posed by the explosive increase in the prevalence of overweight/obesity in the population at large. Given the enormity of the problem, it is necessary to differentiate between the CVD risk related to obesity per se, as distinct from the fact that the prevalence of insulin resistance and compensatory hyperinsulinemia are increased in overweight/obese individuals. Although the majority of individuals in the general population that can be considered insulin resistant are also overweight/obese, not all overweight/obese persons are insulin resistant. Furthermore, the cluster of abnormalities associated with insulin resistance - namely, glucose intolerance, hyperinsulinemia, dyslipidemia, and elevated plasma C-reactive protein concentrations -- is limited to the subset of overweight/obese individuals that are also insulin resistant. Of greater clinical relevance is the fact that significant improvement in these metabolic abnormalities following weight loss is seen only in the subset of

  3. Cladosporium Avr2 inhibits tomato Rcr3 protease required for Cf-2-dependent disease resistance

    NARCIS (Netherlands)

    Rooney, H.C.E.; Klooster, van t J.W.; Hoorn, van der R.A.L.; Joosten, M.H.A.J.; Jones, J.D.G.; Wit, de P.J.G.M.

    2005-01-01

    How plants recognize pathogens and activate defense is still mysterious. Direct interaction between pathogen avirulence (Avr) proteins and plant disease resistance proteins is the exception rather than the rule. During infection, Cladosporium fulvum secretes Avr2 protein into the apoplast of tomato

  4. Cytogenetic Mapping of Disease Resistance Genes and Analysis of Their Distribution Features on Chromosomes in Maize

    Institute of Scientific and Technical Information of China (English)

    LiLi-jia; SongYun-chun

    2003-01-01

    Cytogenetic maps of four clusters of disease resistance genes were generated by ISH of the two RFLP markers tightly linked to and flanking each of maize resistance genes and the cloned resistance genes from other plant species onto maize chromosomes, combining with data published before. These genes include Helminthosporium turcium Pass resistance genes Htl, Htnl and Ht2, Helminthosporium maydis Nisik resistance genes Rhml and Rhm2,maize dwarf mosaic virus resistance gene Mdml, wheat streak mosaic virus resistance gene Wsml, Helminthosporium carbonum ULLstrup resistance gene Hml and the cloned Xanthomonas oryzae pv. Oryzae resistance gene Xa21 of rice, Cladosporium fulvum resistance genes Cf-9 and Cf-2. 1 of tomato, and Pseudomonas syringae resistance gene RPS2 of Arabidopsis. Most of the tested disease resistance genes located on the four chromosomes, i. e. , chromosomesl, 3, 6 and 8, and they closely distributed at the interstitial regions of these chromosomal long arms with percentage distances ranging 31.44(±3.72)-72.40(±3. 25) except for genes Rhml, Rhm2, Mdml and Wsml which mapped on the satellites of the short arms of chromosome6. It showed that the tested RFLP markers and genes were duplicated or triplicated in maize genome. Homology and conservation of disease resistance genes among species, and relationship between distribution features and functions of the genes were discussed. The results provide important scientific basis for deeply understanding structure and function of disease resistance genes and breeding in maize.

  5. Insulin resistance and chronic liver disease

    Science.gov (United States)

    Kawaguchi, Takumi; Taniguchi, Eitaro; Itou, Minoru; Sakata, Masahiro; Sumie, Shuji; Sata, Michio

    2011-01-01

    Increased insulin resistance is frequently associated with chronic liver disease and is a pathophysiological feature of hepatogenous diabetes. Distinctive factors including hepatic parenchymal cell damage, portal-systemic shunting and hepatitis C virus are responsible for the development of hepatogenous insulin resistance/diabetes. Although it remains unclear whether insulin secretion from pancreatic beta cells is impaired as it is in type 2 diabetes, retinopathic and cardiovascular risk is low and major causes of death in cirrhotic patients with diabetes are liver failure, hepatocellular carcinoma and gastrointestinal hemorrhage. Hemoglobin A1c is an inaccurate marker for the assessment and management of hepatogenous diabetes. Moreover, exogenous insulin or sulfonylureas may be harmful because these agents may promote hepatocarcinogenesis. Thus, pathogenesis, cause of death, assessment and therapeutic strategy for hepatogenous insulin resistance/diabetes differ from those for lifestyle-related type 2 diabetes. In this article, we review features of insulin resistance in relationship to chronic liver disease. We also discuss the impact of anti-diabetic agents on interferon treatment and hepatocarcinogenesis. PMID:21731901

  6. Transgenic animals resistant to infectious diseases.

    Science.gov (United States)

    Tiley, L

    2016-04-01

    The list of transgenic animals developed to test ways of producing livestock resistant to infectious disease continues to grow. Although the basic techniques for generating transgenic animals have not changed very much in the ten years since they were last reviewed for the World Organisation for Animal Health, one recent fundamental technological advance stands to revolutionise genome engineering. The advent of technically simple and efficient site-specific gene targeting has profound implications for genetically modifying livestock species.

  7. How glyphosate affects plant disease development: it is more than enhanced susceptibility.

    Science.gov (United States)

    Hammerschmidt, Ray

    2017-01-09

    Glyphosate has been shown to affect the development of plant disease in several ways. Plants utilize phenolic and other shikimic acid pathway-derived compounds as part of their defense against pathogens, and glyphosate inhibits the biosynthesis of these compounds via its mode of action. Several studies have shown a correlation between enhanced disease and suppression of phenolic compound production after glyphosate. Glyphosate-resistant crop plants have also been studied for changes in resistance as a result of carrying the glyphosate resistance trait. The evidence indicates that neither the resistance trait nor application of glyphosate to glyphosate-resistant plants increases susceptibility to disease. The only exceptions to this are cases where glyphosate has been shown to reduce rust diseases on glyphosate-resistant crops, supporting a fungicidal role for this chemical. Finally, glyphosate treatment of weeds or volunteer crops can cause a temporary increase in soil-borne pathogens that may result in disease development if crops are planted too soon after glyphosate application. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. Genetics of insect resistance to plant defence

    NARCIS (Netherlands)

    Vermeer, K.M.C.A.

    2014-01-01

      Plants are chemically defended against insect herbivory in various ways. They produce a broad range of secondary metabolites that may be toxic or deterrent to insects. Specialist insects, however, are often capable of overcoming these defences. The yellow striped flea beetle (Phyllotreta nem

  9. Genetics of insect resistance to plant defence

    NARCIS (Netherlands)

    Vermeer, K.M.C.A.

    2014-01-01

      Plants are chemically defended against insect herbivory in various ways. They produce a broad range of secondary metabolites that may be toxic or deterrent to insects. Specialist insects, however, are often capable of overcoming these defences. The yellow striped flea beetle (Phyllotreta nem

  10. Genetics of insect resistance to plant defence

    NARCIS (Netherlands)

    Vermeer, K.M.C.A.

    2014-01-01

      Plants are chemically defended against insect herbivory in various ways. They produce a broad range of secondary metabolites that may be toxic or deterrent to insects. Specialist insects, however, are often capable of overcoming these defences. The yellow striped flea beetle (Phyllotreta

  11. Recent Advances in Cloning and Characterization of Disease Resistance Genes in Rice

    Institute of Scientific and Technical Information of China (English)

    Liang-Ying Dai; Xiong-Lun Liu; Ying-Hui Xiao; Guo-Liang Wang

    2007-01-01

    Rice diseases caused by fungi, bacteria and viruses are one of the major constraints for sustainable rice (Oryza sativa L.) production worldwide. The use of resistant cultivars is considered the most economical and effective method to control rice diseases. In the last decade, a dozen resistance genes against the fungal pathogen Magnaporthe grisea and the bacterial pathogen Xanthomonas oryzae pv. oryzae have been cloned. Approximately half of them encode nuclear binding site (NBS) and leucine rich repeat (LRR)-containing proteins, the most common type of cloned plant resistance genes. Interestingly, four of them encode novel proteins which have not been identified in other plant species, suggesting that unique mechanisms might be involved in rice defense responses. This review summarizes the recent advances in cloning and characterization of disease resistance genes in rice and presents future perspectives for in-depth molecular analysis of the function and evolution of rice resistance genes and their interaction with avirulence genes in pathogens.

  12. Genetics of adult plant stripe rust resistance in CSP44, a selection from Australian wheat

    Indian Academy of Sciences (India)

    Renu Khanna; U. K. Bansal; R. G. Saini

    2005-12-01

    Wheat line CSP44, a selection from an Australian bread wheat cultivar Condor, has shown resistance to stripe rust in India since the last twenty years. Seedlings and adult plants of CSP44 showed susceptible infection types against stripe rust race 46S119 but displayed average terminal disease severity of 2.67 on adult plants against this race as compared to 70.33 of susceptible Indian cultivar, WL711. This suggests the presence of nonhypersensitive adult plant stripe rust resistance in the line CSP44. The evaluation of F1, F2 and F3 generations and F6 SSD families from the cross of CSP44 with susceptible wheat cultivar WL711 for stripe rust severity indicated that the resistance in CSP44 is based on two genes showing additive effect. One of these two genes is Yr18 and the second gene is not yet described.

  13. The occurrence of postharvest diseases on apples resistant to scab

    Directory of Open Access Journals (Sweden)

    Hanna Bryk

    2012-12-01

    Full Text Available The occurrence of storage diseases on fruit of seven scab resistant apple cultivars (Freedom, Rajka, Topaz, Rubinola, Enterprise, Goldstar, GoldRush grafted on M.9 was investigated in 2001-2005. The trees were planted in 1995. It was found that after storage (4 and 6 months at 2°C, 85-90% RH the most severe appeared to be bull's eye rot (Pezicula spp.. The most sensitive cultivars to this disease were: Topaz, Freedom, Goldstar, the least sensitive were Rubinola, Enterprise, Rajka. Other postharvest diseases like gray mold (Botrytis cinerea, blue mold (Penicillium expansum and brown rot (Monilinia fructigena were not common. 'Rajka' and 'Goldstar' were susceptible to bitter pit, and 'Freedom' to superficial scald.

  14. Plant disease diagnostic capabilities and networks.

    Science.gov (United States)

    Miller, Sally A; Beed, Fen D; Harmon, Carrie Lapaire

    2009-01-01

    Emerging, re-emerging and endemic plant pathogens continue to challege our ability to safeguard plant health worldwide. Further, globalization, climate change, increased human mobility, and pathogen and vector evolution have combined to increase the spread of invasive plant pathogens. Early and accurate diagnoses and pathogen surveillance on local, regional, and global scales are necessary to predict outbreaks and allow time for development and application of mitigation strategies. Plant disease diagnostic networks have developed worldwide to address the problems of efficient and effective disease diagnosis and pathogen detection, engendering cooperation of institutions and experts within countries and across national borders. Networking maximizes impact in the face of shrinking government investments in agriculture and diminishing human resource capacity in diagnostics and applied pathology. New technologies promise to improve the speed and accuracy of disease diagnostics and pathogen detection. Widespread adoption of standard operating procedures and diagnostic laboratory accreditation serve to build trust and confidence among institutions. Case studies of national, regional, and international diagnostic networks are presented.

  15. Reduction of lesion growth rate of late blight plant disease in transgenic potato expressing harpin protein

    Institute of Scientific and Technical Information of China (English)

    李汝刚; 范云六

    1999-01-01

    Using harpin protein gene from apple fire blight pathogen Erwinia amylavora and potato prp1-1 promoter as main DNA elements, the feasibility of using pathogen infection-induced hypersensitive response was explored as a new strategy of engineering fungal disease resistance. Three plant transformation vectors were constructed and 68 transgenic potato plants were produced through Agrobacterium mediated transformation method. Southern, Northern and Western blot analysis demonstrated the insertion, transcription and protein expression of harpin protein gene in transgenic plants. Disease resistance test using a complex race of Phytophthora infestans as challenging pathogen showed that both constitutive and pathogen infection-induced expression of harpin protein gene in transgenic potato reduced the lesion growth rate of fungus. Among plants where harpin protein gene expression was induced only by fungus infection, two plants were found to be highly resistant to P. infestans infection. Fungal hyphae were not pr

  16. Tomato plant inheritance of antixenotic resistance to tomato leafminer

    Directory of Open Access Journals (Sweden)

    Adilson de Castro Antônio

    2011-01-01

    Full Text Available The objective of this work was to determine the inheritance of resistance by antixenosis in tomato plants (Lycopersicon esculentum to tomato leafminer [Tuta absoluta (Lepidoptera: Gelechiidae]. Evaluations were performed for tomato plants of the generations P1, P2, F1, F2, RC1 and RC2. The measured characteristic in the parents, BGH-1497 (P2 male and 'Santa Clara' (P1 female, and in the F1, F2, RC1 and RC2 generations was the number of eggs per plant. This number was converted to the oviposition nonpreference index. The inheritance of antixenosis resistance of genotype BGH-1497 is ruled by a gene of greater effect and polygenes in epistatic interactions, with a phenotypic proportion of 13:3 between susceptible and resistant genotypes, respectively.

  17. Systemic Acquired Resistance and Signal Transduction in Plant

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-qing; GUO Jian-bo

    2003-01-01

    Systemic acquired resistance (SAR), known as the broad-spectrum, inducible plant immunity,is a defense response triggered by pathogen infection. The response starts from the recognition of plant resist-ance (R) with the corresponding avirulence (avr) gene from the pathogen. There are some genes for conver-gence of signals downstream of different R/avr interacting partners into a single signaling pathway. Salicylicacid (SA) is required for the induction of SAR and involved in transducing the signal in target tissues. The SAsignal is transduced through NPR1, a nuclear-localized protein that interacts with transcription factors thatare involved in regulating SA-mediated gene expression. Some chemicals that mimic natural signaling com-pounds can also activate SAR. The application of biochemical activators to agriculture for plant protection is anovel idea for developing green chemical pesticide.

  18. Parasitic plants of the genus Cuscuta and their interaction with susceptible and resistant host plants.

    Science.gov (United States)

    Kaiser, Bettina; Vogg, Gerd; Fürst, Ursula B; Albert, Markus

    2015-01-01

    By comparison with plant-microbe interaction, little is known about the interaction of parasitic plants with their hosts. Plants of the genus Cuscuta belong to the family of Cuscutaceae and comprise about 200 species, all of which live as stem holoparasites on other plants. Cuscuta spp. possess no roots nor fully expanded leaves and the vegetative portion appears to be a stem only. The parasite winds around plants and penetrates the host stems via haustoria, forming direct connections to the vascular bundles of their hosts to withdraw water, carbohydrates, and other solutes. Besides susceptible hosts, a few plants exist that exhibit an active resistance against infestation by Cuscuta spp. For example, cultivated tomato (Solanum lycopersicum) fends off Cuscuta reflexa by means of a hypersensitive-type response occurring in the early penetration phase. This report on the plant-plant dialog between Cuscuta spp. and its host plants focuses on the incompatible interaction of C. reflexa with tomato.

  19. Parasitic plants of the genus Cuscuta and their interaction with susceptible and resistant host plants

    Directory of Open Access Journals (Sweden)

    Bettina eKaiser

    2015-02-01

    Full Text Available By comparison with plant-microbe interaction, little is known about the interaction of parasitic plants with their hosts. Plants of the genus Cuscuta belong to the family of Cuscutaceae and comprise about 200 species, all of which live as stem holoparasites on other plants. Cuscuta spp. possess no roots nor fully expanded leaves and the vegetative portion appears to be a stem only. The parasite winds around plants and penetrates the host stems via haustoria, forming direct connections to the vascular bundles of their hosts to withdraw water, carbohydrates and other solutes. Besides susceptible hosts, a few plants exist that exhibit an active resistance against infestation by Cuscuta spp. For example, cultivated tomato (Solanum lycopersicum fends off Cuscuta reflexa by means of a hypersensitive-type response occurring in the early penetration phase. This report on the plant-plant dialogue between Cuscuta spp. and its host plants focuses on the incompatible interaction of Cuscuta reflexa with tomato.

  20. Research Progress of Plant Non-host Resistance%植物非寄主抗性的研究进展

    Institute of Scientific and Technical Information of China (English)

    于建水; 封立波

    2012-01-01

    综述了植物非寄主抗性的类型和抗病机理,阐明了植物非寄主抗性在植物抗病中的作用,以期为培育稳定持久的抗性新品种提供理论和实践依据。%The article reviewed the type and the disease-resistant mechanism of plant non-host resistance,clarified the effect of plant non-host resistance in plant disease resistant,in order to provide theoretical and practical basis for breeding new stable and sustainable resistant breed.

  1. The dissection and SSR mapping of a high-temperature adult-plant stripe rust resistance gene in American spring wheat cultivar Alturas

    Science.gov (United States)

    Stripe rust is one of major diseases in wheat production worldwide. The best economic and efficient method is to utilize resistant varieties. Alturas has high-temperature adult-plant resistance. In order to determine stripe rust resistance characteristics, resistance gene combination and molecular m...

  2. Obtaining transgenic rice resistant to rice fungal blast disease by controlled cell death strategy

    Institute of Scientific and Technical Information of China (English)

    MAO Shengji; GU Hongya; QU Lijia; CHEN Zhangliang

    2003-01-01

    The strategy of the two-component system, composed of Barnase and Barstar which encode RNase and a specific inhibitor to the RNase respectively, is adopted to obtain transgenic rice resistant to rice fungal blast disease. In this study, two chimeric promoters, induced by rice blast fungus pathogen (Magnaporthe grisea), are fused with Barnase respectively to construct two plant expression vectors, pWBNBS and pPBNBS together with the Barstar driven by CaMV 35S promoter. The resistance of the transgenic rice lines to rice blast fungus disease and rice blight disease are evaluated. The results show that (1) the expression of Barnase is induced in rice leaves when inoculated with the spores of Magnaporthe grisea; (2) the induced expression level of Barnase surpasses the level of Barstar, which elicits a similar hypersensitive response (HR) in the leaves, and the transgenic plant shows high resistance to the rice fungal blast disease; and (3) transgenic rice plants also show obvious resistance to rice bacterial blight disease. Taken together, these results suggest that the transgenic rice plants harboring this two-component system acquire relatively broad spectrum resistance against pathogens, especially high resistance to rice fungal pathogen.

  3. Appraisal of wheat germplasm for adult plant resistance against stripe rust

    Directory of Open Access Journals (Sweden)

    Saleem Kamran

    2015-12-01

    Full Text Available The resurgence of wheat stripe rust is of great concern for world food security. Owing to resistance breakdown and the appearance of new virulent high-temperature adapted races of Puccinia striiformis f. sp. tritici (Pst, many high yielding commercial varieties in the country lost their yield potential. Searching for new sources of resistance is the best approach to mitigate the problem. Quantitative resistance (partial or adult plant or durable resistance is reported to be more stable than race specific resistance. In the current perusal, a repertoire of 57 promising wheat lines along with the KLcheck line Morocco, developed through hybridisation and selection of local and international lines with International Maize and Wheat Improvement Center (CIMMYT origin, were evaluated under natural field conditions at Nuclear Institute for Agriculture and Biology (NIAB during the 2012−2013 and 2013−2014 time periods. Final rust severity (FRS, the area under the rust progress curve (AURPC, the relative area under the rust progress curve (rAURPC, and the coefficient of infection (CI were unraveled to infer the level of quantitative resistance. Final rust severity was recorded when the susceptible check exhibited 100% severity. There were 21 lines which were immune (no disease, 16 which were resistant, five moderately resistant, two resistant-to-moderately resistant, one moderately resistant-to-moderately susceptible, 5 moderately susceptible-to-susceptible, one moderately susceptible, and six exhibited a susceptible response. Nevertheless, 51 lines exhibited a high level of partial resistance while the three lines, NW-5-1212-1, NW-7-30-1, and NW-7-5 all showed a moderate level of partial resistance based on FRS, while 54 lines, on the basis of AURPC and rAURPC, were identified as conferring a high level of partial resistance. Moreover, adult plant resistance was conferred by 47 wheat lines, based on CI value. It was striking that, 13 immune lines

  4. High throughput phenotyping for aphid resistance in large plant collections

    Directory of Open Access Journals (Sweden)

    Chen Xi

    2012-08-01

    Full Text Available Abstract Background Phloem-feeding insects are among the most devastating pests worldwide. They not only cause damage by feeding from the phloem, thereby depleting the plant from photo-assimilates, but also by vectoring viruses. Until now, the main way to prevent such problems is the frequent use of insecticides. Applying resistant varieties would be a more environmental friendly and sustainable solution. For this, resistant sources need to be identified first. Up to now there were no methods suitable for high throughput phenotyping of plant germplasm to identify sources of resistance towards phloem-feeding insects. Results In this paper we present a high throughput screening system to identify plants with an increased resistance against aphids. Its versatility is demonstrated using an Arabidopsis thaliana activation tag mutant line collection. This system consists of the green peach aphid Myzus persicae (Sulzer and the circulative virus Turnip yellows virus (TuYV. In an initial screening, with one plant representing one mutant line, 13 virus-free mutant lines were identified by ELISA. Using seeds produced from these lines, the putative candidates were re-evaluated and characterized, resulting in nine lines with increased resistance towards the aphid. Conclusions This M. persicae-TuYV screening system is an efficient, reliable and quick procedure to identify among thousands of mutated lines those resistant to aphids. In our study, nine mutant lines with increased resistance against the aphid were selected among 5160 mutant lines in just 5 months by one person. The system can be extended to other phloem-feeding insects and circulative viruses to identify insect resistant sources from several collections, including for example genebanks and artificially prepared mutant collections.

  5. Progress in Research of Bacteria Fertilizer Strengthening Resistance of Plants

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Bacteria fertilizer is used most widely among all kinds of microbial fertilizers. We summarize the research headway of bacteria fertilizer. It mainly focuses on bacteria fertilizer improving the stress resistance of plant. Then we can offer basis to research and exploit bacteria fertilizer. These bacteria include azotobacter, photosynthetic bacteria, Bacillus mucilaginosus siliceous, phosphorus bacteria, plant growth-promoting rhizobacteria(PGPR), effective microorganism(EM).

  6. Cortical microtubules are responsible for gravity resistance in plants.

    Science.gov (United States)

    Hoson, Takayuki; Matsumoto, Shouhei; Soga, Kouichi; Wakabayashi, Kazuyuki

    2010-06-01

    Mechanical resistance to the gravitational force is a principal gravity response in plants distinct from gravitropism. In the final step of gravity resistance, plants increase the rigidity of their cell walls. Here we discuss the role of cortical microtubules, which sustain the function of the cell wall, in gravity resistance. Hypocotyls of Arabidopsis tubulin mutants were shorter and thicker than the wild-type, and showed either left-handed or right-handed helical growth at 1 g. The degree of twisting phenotype was intensified under hypergravity conditions. Hypergravity also induces reorientation of cortical microtubules from transverse to longitudinal directions in epidermal cells. In tubulin mutants, the percentage of cells with longitudinal microtubules was high even at 1 g, and it was further increased by hypergravity. The left-handed helical growth mutants had right-handed microtubule arrays, whereas the right-handed mutant had left-handed arrays. Moreover, blockers of mechanoreceptors suppressed both the twisting phenotype and reorientation of microtubules in tubulin mutants. These results support the hypothesis that cortical microtubules play an essential role in maintenance of normal growth phenotype against the gravitational force, and suggest that mechanoreceptors are involved in signal perception in gravity resistance. Space experiments will confirm whether this view is applicable to plant resistance to 1 g gravity, as to the resistance to hypergravity.

  7. Rapid Phenotyping Adult Plant Resistance to Stem Rust in Wheat Grown under Controlled Conditions.

    Science.gov (United States)

    Riaz, Adnan; T Hickey, Lee

    2017-01-01

    Stem rust (SR) or black rust caused by Puccinia graminis f. sp. tritici is one of the most common diseases of wheat (Triticum aestivum L.) crops globally. Among the various control measures, the most efficient and sustainable approach is the deployment of genetically resistant cultivars. Traditionally, wheat breeding programs deployed genetic resistance in cultivars, but unknowingly this is often underpinned by a single seedling resistance gene, which is readily overcome by the pathogen. Nowadays, adult plant resistance (APR) is a widely adopted form of rust resistance because more durable mechanisms often underpin it. However, only a handful of SR APR genes are available, so breeders currently strive to combine seedling and APR genes. Phenotyping adult wheat plants for resistance to SR typically involves evaluation in the field. But establishing a rust nursery can be challenging, and screening is limited to once a year. This slows down research efforts to isolate new APR genes and breeding of genetically resistant cultivars.In this study, we report a protocol for rapid evaluation of adult wheat plants for resistance to stem rust. We demonstrate the technique by evaluating a panel of 16 wheat genotypes consisting of near isogenic lines (NILs) for known Sr genes (i.e., Sr2, Sr33, Sr45, Sr50, Sr55, Sr57, and Sr58) and three landraces carrying uncharacterized APR from the N. I. Vavilov Institute of Plant Genetic Resources (VIR). The method can be completed in just 10 weeks and involves two inoculations: first conducted at seedling stage and a second at the adult stage (using the same plants). The technique can detect APR, such as that conferred by APR gene Sr2, along with pseudo-black chaff (the morphological marker). Phenotyping can be conducted throughout the year, and is fast and resource efficient. Further, the phenotyping method can be applied to screen breeding populations or germplasm accessions using local or exotic races of SR.

  8. Ralstonia solanacearum extracellular polysaccharide is a specific elicitor of defense responses in wilt-resistant tomato plants.

    Directory of Open Access Journals (Sweden)

    Annett Milling

    Full Text Available Ralstonia solanacearum, which causes bacterial wilt of diverse plants, produces copious extracellular polysaccharide (EPS, a major virulence factor. The function of EPS in wilt disease is uncertain. Leading hypotheses are that EPS physically obstructs plant water transport, or that EPS cloaks the bacterium from host plant recognition and subsequent defense. Tomato plants infected with R. solanacearum race 3 biovar 2 strain UW551 and tropical strain GMI1000 upregulated genes in both the ethylene (ET and salicylic acid (SA defense signal transduction pathways. The horizontally wilt-resistant tomato line Hawaii7996 activated expression of these defense genes faster and to a greater degree in response to R. solanacearum infection than did susceptible cultivar Bonny Best. However, EPS played different roles in resistant and susceptible host responses to R. solanacearum. In susceptible plants the wild-type and eps(- mutant strains induced generally similar defense responses. But in resistant Hawaii7996 tomato plants, the wild-type pathogens induced significantly greater defense responses than the eps(- mutants, suggesting that the resistant host recognizes R. solanacearum EPS. Consistent with this idea, purified EPS triggered significant SA pathway defense gene expression in resistant, but not in susceptible, tomato plants. In addition, the eps(- mutant triggered noticeably less production of defense-associated reactive oxygen species in resistant tomato stems and leaves, despite attaining similar cell densities in planta. Collectively, these data suggest that bacterial wilt-resistant plants can specifically recognize EPS from R. solanacearum.

  9. Overexpression of a Chitinase Gene from Trichoderma asperellum Increases Disease Resistance in Transgenic Soybean.

    Science.gov (United States)

    Zhang, Fuli; Ruan, Xianle; Wang, Xian; Liu, Zhihua; Hu, Lizong; Li, Chengwei

    2016-12-01

    In the present study, a chi gene from Trichoderma asperellum, designated Tachi, was cloned and functionally characterized in soybean. Firstly, the effects of sodium thiosulfate on soybean Agrobacterium-mediated genetic transformation with embryonic tip regeneration system were investigated. The transformation frequency was improved by adding sodium thiosulfate in co-culture medium for three soybean genotypes. Transgenic soybean plants with constitutive expression of Tachi showed increased resistance to Sclerotinia sclerotiorum compared to WT plants. Meanwhile, overexpression of Tachi in soybean exhibited increased reactive oxygen species (ROS) level as well as peroxidase (POD) and catalase (SOD) activities, decreased malondialdehyde (MDA) content, along with diminished electrolytic leakage rate after S. sclerotiorum inoculation. These results suggest that Tachi can improve disease resistance in plants by enhancing ROS accumulation and activities of ROS scavenging enzymes and then diminishing cell death. Therefore, Tachi represents a candidate gene with potential application for increasing disease resistance in plants.

  10. Priming of plant resistance by natural compounds. Hexanoic acid as a model

    Directory of Open Access Journals (Sweden)

    Paz eAranega Bou

    2014-10-01

    Full Text Available Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on hexanoic acid (Hx, proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the SA and JA pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-induced resistance (Hx-IR findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound.

  11. Transgenic banana expressing Pflp gene confers enhanced resistance to Xanthomonas wilt disease.

    Science.gov (United States)

    Namukwaya, B; Tripathi, L; Tripathi, J N; Arinaitwe, G; Mukasa, S B; Tushemereirwe, W K

    2012-08-01

    Banana Xanthomonas wilt (BXW), caused by Xanthomonas campestris pv. musacearum, is one of the most important diseases of banana (Musa sp.) and currently considered as the biggest threat to banana production in Great Lakes region of East and Central Africa. The pathogen is highly contagious and its spread has endangered the livelihood of millions of farmers who rely on banana for food and income. The development of disease resistant banana cultivars remains a high priority since farmers are reluctant to employ labor-intensive disease control measures and there is no host plant resistance among banana cultivars. In this study, we demonstrate that BXW can be efficiently controlled using transgenic technology. Transgenic bananas expressing the plant ferredoxin-like protein (Pflp) gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of banana. These transgenic lines were characterized by molecular analysis. After challenge with X. campestris pv. musacearum transgenic lines showed high resistance. About 67% of transgenic lines evaluated were completely resistant to BXW. These transgenic lines did not show any disease symptoms after artificial inoculation of in vitro plants under laboratory conditions as well as potted plants in the screen-house, whereas non-transgenic control plants showed severe symptoms resulting in complete wilting. This study confirms that expression of the Pflp gene in banana results in enhanced resistance to BXW. This transgenic technology can provide a timely solution to the BXW pandemic.

  12. Relationship between resistance and growth of Trifolium repens plants and their disease history%白车轴草(Trifolium repens)植株抗病性和生长与植物病史的关系

    Institute of Scientific and Technical Information of China (English)

    刘登义; LarsEricson; 等

    2003-01-01

    从白车轴草(Trifolium repens)自然种群中采集无白车轴草单孢锈菌病史的无性系(clones)17个,有白车轴草单孢锈菌病史的无性系14个,分别作为抗病型和感受型植物实验材料;采集白车轴草单孢锈菌(Uromyces trifolii-repentis)菌系(strains)10个,作为病菌实验材料.分别设置并进行了两个温室实验、一个田间盆栽实验和一个原生长地移栽实验,实验处理上分对照、单菌系接种和10个菌系接种等3种.实验结果表明,无论是用单菌系接种还是10个菌系接种,植株发病的概率和程度均与其抗病性有关,抗病型植株(无病史)发病的概率和程度显著低于感受型(有病史)植株.在相同处理的实验中(无论是田间实验还是温室实验),无病史植株和有病史植株的生长无显著差异;不同处理田间实验植株的生长有显著差异,病情愈重,生长愈差.无病史植株的抗病性明显强于有病史植株.但是, 原生长地的移栽实验结果表明,在无病原菌存在的情况下,有病史植株的(叶)生长显著好于无病史植株.可以认为,研究生物个体对环境因子反应性差异的实验应当在自然条件下和自然梯度范围内进行.%17 healthy host clones and 14 clones originally diseased with the annual rust, Uromyces trifolii-repentis, were sampled from the natural population of Trifolium repens, which were used as the experimental plant materials. 10 rust strains of Uromyces trifolii-repentis were collected for the experimental inoculation. Two greenhouse and two field experiments were done, with three treatments as inoculated with one rust strain, inoculated with ten rust strains and controls, respectively. The results showed that originally healthy plants were more resistant, and originally diseased ones were more susceptible to the rust. However, there was a considerable overlap among some of the clones. Pot experiments, both in the greenhouse and in the field, revealed no

  13. Exploring Antibiotic Resistance Genes and Metal Resistance Genes in Plasmid Metagenomes from Wastewater Treatment Plants

    Directory of Open Access Journals (Sweden)

    An-Dong eLi

    2015-09-01

    Full Text Available Plasmids operate as independent genetic elements in microorganism communities. Through horizontal gene transfer, they can provide their host microorganisms with important functions such as antibiotic resistance and heavy metal resistance. In this study, six metagenomic libraries were constructed with plasmid DNA extracted from influent, activated sludge and digested sludge of two wastewater treatment plants. Compared with the metagenomes of the total DNA extracted from the same sectors of the wastewater treatment plant, the plasmid metagenomes had significantly higher annotation rates, indicating that the functional genes on plasmids are commonly shared by those studied microorganisms. Meanwhile, the plasmid metagenomes also encoded many more genes related to defense mechanisms, including ARGs. Searching against an antibiotic resistance genes (ARGs database and a metal resistance genes (MRGs database revealed a broad-spectrum of antibiotic (323 out of a total 618 subtypes and metal resistance genes (23 out of a total 23 types on these plasmid metagenomes. The influent plasmid metagenomes contained many more resistance genes (both ARGs and MRGs than the activated sludge and the digested sludge metagenomes. Sixteen novel plasmids with a complete circular structure that carried these resistance genes were assembled from the plasmid metagenomes. The results of this study demonstrated that the plasmids in wastewater treatment plants could be important reservoirs for resistance genes, and may play a significant role in the horizontal transfer of these genes.

  14. Suppression of plant resistance gene-based immunity by a fungal effector.

    Directory of Open Access Journals (Sweden)

    Petra M Houterman

    2008-05-01

    Full Text Available The innate immune system of plants consists of two layers. The first layer, called basal resistance, governs recognition of conserved microbial molecules and fends off most attempted invasions. The second layer is based on Resistance (R genes that mediate recognition of effectors, proteins secreted by pathogens to suppress or evade basal resistance. Here, we show that a plant-pathogenic fungus secretes an effector that can both trigger and suppress R gene-based immunity. This effector, Avr1, is secreted by the xylem-invading fungus Fusarium oxysporum f.sp. lycopersici (Fol and triggers disease resistance when the host plant, tomato, carries a matching R gene (I or I-1. At the same time, Avr1 suppresses the protective effect of two other R genes, I-2 and I-3. Based on these observations, we tentatively reconstruct the evolutionary arms race that has taken place between tomato R genes and effectors of Fol. This molecular analysis has revealed a hitherto unpredicted strategy for durable disease control based on resistance gene combinations.

  15. Inoculation of Transgenic Resistant Potato by Phytophthora infestans Affects Host Plant Choice of a Generalist Moth.

    Science.gov (United States)

    Abreha, Kibrom B; Alexandersson, Erik; Vossen, Jack H; Anderson, Peter; Andreasson, Erik

    2015-01-01

    Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes), the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-target organisms. Thus, we examined the effect of P. infestans itself and introduction of an Rpi-gene into the crop on host plant preference of the generalist insect herbivore, Spodoptera littoralis (Lepidoptera: Noctuidae). In two choice bioassays, S. littoralis preferred to oviposit on P. infestans-inoculated plants of both the susceptible potato (cv. Desiree) and an isogenic resistant clone (A01-22: cv. Desiree transformed with Rpi-blb1), when compared to uninoculated plants of the same genotype. Both cv. Desiree and clone A01-22 were equally preferred for oviposition by S. littoralis when uninoculated plants were used, while cv. Desiree received more eggs compared to the resistant clone when both were inoculated with the pathogen. No significant difference in larval and pupal weight was found between S. littoralis larvae reared on leaves of the susceptible potato plants inoculated or uninoculated with P. infestans. Thus, the herbivore's host plant preference in this system was not directly associated with larval performance. The results indicate that the Rpi-blb1 based resistance in itself does not influence insect behavior, but that herbivore oviposition preference is affected by a change in the plant-microbe interaction.

  16. Inoculation of Transgenic Resistant Potato by Phytophthora infestans Affects Host Plant Choice of a Generalist Moth.

    Directory of Open Access Journals (Sweden)

    Kibrom B Abreha

    Full Text Available Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes, the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-target organisms. Thus, we examined the effect of P. infestans itself and introduction of an Rpi-gene into the crop on host plant preference of the generalist insect herbivore, Spodoptera littoralis (Lepidoptera: Noctuidae. In two choice bioassays, S. littoralis preferred to oviposit on P. infestans-inoculated plants of both the susceptible potato (cv. Desiree and an isogenic resistant clone (A01-22: cv. Desiree transformed with Rpi-blb1, when compared to uninoculated plants of the same genotype. Both cv. Desiree and clone A01-22 were equally preferred for oviposition by S. littoralis when uninoculated plants were used, while cv. Desiree received more eggs compared to the resistant clone when both were inoculated with the pathogen. No significant difference in larval and pupal weight was found between S. littoralis larvae reared on leaves of the susceptible potato plants inoculated or uninoculated with P. infestans. Thus, the herbivore's host plant preference in this system was not directly associated with larval performance. The results indicate that the Rpi-blb1 based resistance in itself does not influence insect behavior, but that herbivore oviposition preference is affected by a change in the plant-microbe interaction.

  17. Host-plant resistance to western flower thrips in Arabidopsis

    NARCIS (Netherlands)

    Thoen, Manus P.M.

    2016-01-01

    Western flower thrips is a pest on a large variety of vegetable, fruit and ornamental crops. The damage these minute slender insects cause in agriculture through feeding and the transmission of tospoviruses requires a sustainable solution. Host-plant resistance is a cornerstone of Integrated Pest Ma

  18. Plant adaptogens increase lifespan and stress resistance in C. elegans

    NARCIS (Netherlands)

    Wiegant, F.A.C.; Surinova, S.; Ytsma, E.; Langelaar-Makkinje, M.; Wikman, G.; Post, J.A.

    2008-01-01

    Extracts of plant adaptogens such as Eleutherococcus senticosus (or Acanthopanax senticosus) and Rhodiola rosea can increase stress resistance in several model systems. We now show that both extracts also increase the mean lifespan of the nematode C. elegans in a dose-dependent way. In

  19. Host-plant resistance to western flower thrips in Arabidopsis

    NARCIS (Netherlands)

    Thoen, Manus P.M.

    2016-01-01

    Western flower thrips is a pest on a large variety of vegetable, fruit and ornamental crops. The damage these minute slender insects cause in agriculture through feeding and the transmission of tospoviruses requires a sustainable solution. Host-plant resistance is a cornerstone of Integrated Pest

  20. High level resistance against rhizomania disease by simultaneously integrating two distinct defense mechanisms.

    Directory of Open Access Journals (Sweden)

    Ourania I Pavli

    Full Text Available With the aim of achieving durable resistance against rhizomania disease of sugar beet, the employment of different sources of resistance to Beet necrotic yellow vein virus was pursued. To this purpose, Nicotiana benthamiana transgenic plants that simultaneously produce dsRNA originating from a conserved region of the BNYVV replicase gene and the HrpZ(Psph protein in a secreted form (SP/HrpZ(Psph were produced. The integration and expression of both transgenes as well as proper production of the harpin protein were verified in all primary transformants and selfed progeny (T1, T2. Transgenic resistance was assessed by BNYVV-challenge inoculation on T2 progeny by scoring disease symptoms and DAS-ELISA at 20 and 30 dpi. Transgenic lines possessing single transformation events for both transgenes as well as wild type plants were included in inoculation experiments. Transgenic plants were highly resistant to virus infection, whereas in some cases immunity was achieved. In all cases, the resistant phenotype of transgenic plants carrying both transgenes was superior in comparison with the ones carrying a single transgene. Collectively, our findings demonstrate, for a first time, that the combination of two entirely different resistance mechanisms provide high level resistance or even immunity against the virus. Such a novel approach is anticipated to prevent a rapid virus adaptation that could potentially lead to the emergence of isolates with resistance breaking properties.

  1. High level resistance against rhizomania disease by simultaneously integrating two distinct defense mechanisms.

    Science.gov (United States)

    Pavli, Ourania I; Tampakaki, Anastasia P; Skaracis, George N

    2012-01-01

    With the aim of achieving durable resistance against rhizomania disease of sugar beet, the employment of different sources of resistance to Beet necrotic yellow vein virus was pursued. To this purpose, Nicotiana benthamiana transgenic plants that simultaneously produce dsRNA originating from a conserved region of the BNYVV replicase gene and the HrpZ(Psph) protein in a secreted form (SP/HrpZ(Psph)) were produced. The integration and expression of both transgenes as well as proper production of the harpin protein were verified in all primary transformants and selfed progeny (T1, T2). Transgenic resistance was assessed by BNYVV-challenge inoculation on T2 progeny by scoring disease symptoms and DAS-ELISA at 20 and 30 dpi. Transgenic lines possessing single transformation events for both transgenes as well as wild type plants were included in inoculation experiments. Transgenic plants were highly resistant to virus infection, whereas in some cases immunity was achieved. In all cases, the resistant phenotype of transgenic plants carrying both transgenes was superior in comparison with the ones carrying a single transgene. Collectively, our findings demonstrate, for a first time, that the combination of two entirely different resistance mechanisms provide high level resistance or even immunity against the virus. Such a novel approach is anticipated to prevent a rapid virus adaptation that could potentially lead to the emergence of isolates with resistance breaking properties.

  2. Plants and phytochemicals for Huntington's disease.

    Science.gov (United States)

    Choudhary, Sunayna; Kumar, Puneet; Malik, Jai

    2013-07-01

    Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive motor dysfunction, including chorea and dystonia, emotional disturbances, memory, and weight loss. The medium spiny neurons of striatum and cortex are mainly effected in HD. Various hypotheses, including molecular genetics, oxidative stress, excitotoxicity, metabolic dysfunction, and mitochondrial impairment have been proposed to explain the pathogenesis of neuronal dysfunction and cell death. Despite no treatment is available to fully stop the progression of the disease, there are treatments available to help control the chorea. The present review deals with brief pathophysiology of the disease, plants and phytochemicals that have shown beneficial effects against HD like symptoms. The literature for the current review was collected using various databases such as Science direct, Pubmed, Scopus, Sci-finder, Google Scholar, and Cochrane database with a defined search strategy.

  3. Advances in Research on Genetically Engineered Plants for Metal Resistance

    Institute of Scientific and Technical Information of China (English)

    Ri-Qing Zhang; Chun-Fang Tang; Shi-Zhi Wen; Yun-Guo Liu; Ke-Lin Li

    2006-01-01

    The engineering application of natural hyperaccumulators in removing or inactivating metal pollutants from soil and surface water in field trials mostly presents the insurmountable shortcoming of low efficiency owing to their little biomass and slow growth. Based on further understanding of the molecular mechanism of metal uptake, translocation, and also the separation, identification, and cloning of some related functional genes, this article highlights and summarizes in detail the advances in research on transgenic techniques, such as Agrobacterium tumefaciens-mediated transformation and particle bombardment, in breeding of plants for metal resistance and accumulation, and points out that deepening the development of transgenic plants is one of the efficient approaches to improving phytoremediation efficiency of metal-contaminated environments. From the viewpoint of sustainable development, governments should strengthen support to the development of genetic engineering for metal resistance and accumulation in plants.

  4. Disease resistance breeding in rose: current status and potential of biotechnological tools.

    Science.gov (United States)

    Debener, Thomas; Byrne, David H

    2014-11-01

    The cultivated rose is a multispecies complex for which a high level of disease protection is needed due to the low tolerance of blemishes in ornamental plants. The most important fungal diseases are black spot, powdery mildew, botrytis and downy mildew. Rose rosette, a lethal viral pathogen, is emerging as a devastating disease in North America. Currently rose breeders use a recurrent phenotypic selection approach and perform selection for disease resistance for most pathogen issues in a 2-3 year field trial. Marker assisted selection could accelerate this breeding process. Thus far markers have been identified for resistance to black spot (Rdrs) and powdery mildew and with the ability of genotyping by sequencing to generate 1000s of markers our ability to identify markers useful in plant improvement should increase exponentially. Transgenic rose lines with various fungal resistance genes inserted have shown limited success and RNAi technology has potential to provide virus resistance. Roses, as do other plants, have sequences homologous to characterized R-genes in their genomes, some which have been related to specific disease resistance. With improving next generation sequencing technology, our ability to do genomic and transcriptomic studies of the resistance related genes in both the rose and the pathogens to reveal novel gene targets to develop resistant roses will accelerate. Finally, the development of designer nucleases opens up a potentially non-GMO approach to directly modify a rose's DNA to create a disease resistant rose. Although there is much potential, at present rose breeders are not using marker assisted breeding primarily because a good suite of marker/trait associations (MTA) that would ensure a path to stable disease resistance is not available. As our genomic analytical tools improve, so will our ability to identify useful genes and linked markers. Once these MTAs are available, it will be the cost savings, both in time and money, that will

  5. Control effect of lanthanum against plant disease

    Institute of Scientific and Technical Information of China (English)

    LIU Yajia; WANG Yan; WANG Fubin; LIU Yuming; CUI Jianyu; HU Lin; MU Kangguo

    2008-01-01

    Effect of La on emergence, growth and development of Isatis indigotica Fort and Festuca arundinacea seedlings was researched by pot experiments of inoculating Rhizoctonia solani and with the mixture of Rhizoctonia solani and Fusarium solani in disinfected soil after the seeds were soaked in the solution with different concentrations of La3+. The results indicated that infection rate decreased and there were significant disease controlling effects on seed rot, bud rot and root rot caused by pathogenic fungi when the seeds were soaked by La3+. Thus, the rates of emergence of Isatis indigotica Fort. And turfgrass Festuca arundinacea were increased. When La3+ concentration was in a proper range, the growth and development of plant seedlings were promoted. Spraying La on rice plants showed a significant controling effect on Rhizoctonia solani. Furthermore, the EC50 of La3+ performed 128.7 and 128.1 mg/L at 1 and 7 d after spraying La in rice plants, respectively. The EC50ofLa3+ performed in vivo (in rice plant) was lower than that in vitro (171.9 mg/L).

  6. Altered disease development in the eui mutants and Eui overexpressors indicates that gibberellins negatively regulate rice basal disease resistance.

    Science.gov (United States)

    Yang, Dong-Lei; Li, Qun; Deng, Yi-Wen; Lou, Yong-Gen; Wang, Mu-Yang; Zhou, Guo-Xing; Zhang, Ying-Ying; He, Zu-Hua

    2008-05-01

    Gibberellins (GAs) form a group of important plant tetracyclic diterpenoid hormones that are involved in many aspects of plant growth and development. Emerging evidence implicates that GAs also play roles in stress responses. However, the role of GAs in biotic stress is largely unknown. Here, we report that knockout or overexpression of the Elongated uppermost internode (Eui) gene encoding a GA deactivating enzyme compromises or increases, respectively, disease resistance to bacterial blight (Xanthomonas oryzae pv. oyrzae) and rice blast (Magnaporthe oryzae). Exogenous application of GA(3) and the inhibitor of GA synthesis (uniconazol) could increase disease susceptibility and resistance, respectively, to bacterial blight. Similarly, uniconazol restored disease resistance of the eui mutant and GA(3) decreased disease resistance of the Eui overexpressors to bacterial blight. Therefore, the change of resistance attributes to GA levels. In consistency with this, the GA metabolism genes OsGA20ox2 and OsGA2ox1 were down-regulated during pathogen challenge. We also found that PR1a induction was enhanced but the SA level was decreased in the Eui overexpressor, while the JA level was reduced in the eui mutant. Together, our current study indicates that GAs play a negative role in rice basal disease resistance, with EUI as a positive modulator through regulating the level of bioactive GAs.

  7. Altered Disease Development in the eui Mutants and Eui Overexpressors Indicates that Gibberellins Negatively Regulate Rice Basal Disease Resistance

    Institute of Scientific and Technical Information of China (English)

    Dong-Lei Yang; Qun Li; Yi-Wen Deng; Yong-Gen Lou; Mu-Yang Wang; Guo-Xing Zhou; Ying-Ying Zhang; Zu-Hua He

    2008-01-01

    Gibberellins (GAs) form a group of important plant tetracyclic diterpenoid hormones that are involved in many aspects of plant growth and development. Emerging evidence implicates that GAs also play roles in stress responses. However, the role of GAs in biotic stress is largely unknown. Here, we report that knockout or overexpression of the Elongated uppermost internode (Eui) gene encoding a GA deactivating enzyme compromises or increases, respectively, disease resistance to bacterial blight (Xanthomonas oryzae pv. oyrzae) and rice blast (Magnaporthe oryzae). Exogenous application of GA and the inhibitor of GA synthesis (uniconazol) could increase disease susceptibility and resistance, respectively, to bacterial blight. Similarly, uniconazol restored disease resistance of the eui mutant and GA3 decreased disease resistance of the Eui overexpressors to bacterial blight. Therefore, the change of resistance attributes to GA levels. In consistency with this, the GA metabolism genes OsGA2Oox2 and OsGA2oxl were down-regulated during pathogen challenge. We also found that PR1a induction was enhanced but the SA level was decreased in the Eui overexpressor, while the JA level was reduced in the eui mutant. Together, our current study indicates that GAs play a negative role in rice basal disease resistance, with EUI as a positive modulator through regulating the level of bioactive GAs.

  8. Hypergravity experiments to evaluate gravity resistance mechanisms in plants.

    Science.gov (United States)

    Soga, Kouichi; Yano, Sachiko; Matsumoto, Shouhei; Hoson, Takayuki

    2015-01-01

    Hypergravity generated by centrifugal acceleration is the only practical method to modify the magnitude of gravitational acceleration for a sufficient duration on Earth and has been used to analyze the nature and mechanism of graviresponse, particularly gravity resistance, in plants. Plant organs are generally resistant to gravitational acceleration. Hypergravity produced from centrifugation speeds in the range of 10-300 × g, which is easily produced by a benchtop centrifuge, is often used during plant experiments. After centrifugation, the plant material is fixed with suitable fixatives in appropriate sample storage containers such as the Chemical Fixation Bag. The material is then analyzed with a variety of methods, depending on the purpose of the experiment. Plant material fixed with the RNAlater(®) solution can be sequentially used for determining the mechanical properties of the cell wall, for RNA extraction (which is necessary for gene expression analysis), for estimating the enzyme activity of the cell wall proteins, and for determining the levels as well as the compositions of cell wall polysaccharides. The plant material can also be used directly for microscopic observation of cellular components such as cortical microtubules.

  9. Cloning and Sequence Analysis of Disease Resistance Gene Analogues from Three Wild Rice Species in Yunnan

    Institute of Scientific and Technical Information of China (English)

    LIU Ji-mei; CHENG Zai-quan; YANG Ming-zhi; WU Cheng-jun; WANG Ling-xian; SUN Yi-ding; HUANG Xing-qi

    2003-01-01

    Two sets of degenerate oligonucleotide primers were designed according to amino acid conservedregions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site andleucine-rich repeats(NBS-LRR), and the plant disease resistance genes which encode serine/threonine proteinkinase(STK). By polymerase chain reaction(PCR), disease resistance gene analogues have been amplified fromthree wild rice species in Yunnan Province, China. The DNA fragments from amplification have been clonedinto the pGEM-T vector respectively. Sequencing of the DNA fragments indicated that 7 classes, 2 classes and6 classes NBS-LRR disease resistance gene analogues from Oryza rufipogon Griff. , Oryza officinalis Wall. ,and Oryza meyeriana Baill. were obtained respectively. The two representative fragments of TO12 from Ory-za officinalis Wall. and TR19 from Oryza rufipogon Griff. belong to the same class and homology of theirsequences are 100%. The result shows that the sequences of the same class disease resistance gene analogueshave no difference among different species of wild rice. 5 classes STK disease resistance gene analogues werealso obtained among which 4 classes from Oryza rufipogon Griff. , 1 class from Oryza officinalis Wall. Bycomparison analysis of amino acid sequences, we found that the obtained disease resistance gene analogues havevery iow identity(low to 25%) with the reported disease resistance gene L6, N, Bs2, Prf, Pto, Lr10 and Xa21etc. The finding suggests that the obtained disease resistance gene analogues are analogues of putative diseaseresistance genes that have not been isolated so far.

  10. Proteomic analysis of the plant-virus interaction in cucumber mosaic virus (CMV) resistant transgenic tomato.

    Science.gov (United States)

    Di Carli, Mariasole; Villani, Maria Elena; Bianco, Linda; Lombardi, Raffaele; Perrotta, Gaetano; Benvenuto, Eugenio; Donini, Marcello

    2010-11-05

    Cucumber mosaic virus (CMV), a member of the Cucumovirus genus, is the causal agent of several plant diseases in a wide range of host species, causing important economic losses in agriculture. Because of the lack of natural resistance genes in most crops, different genetic engineering strategies have been adopted to obtain virus-resistant plants. In a previous study, we described the engineering of transgenic tomato plants expressing a single-chain variable fragment antibody (scFv G4) that are specifically protected from CMV infection. In this work, we characterized the leaf proteome expressed during compatible plant-virus interaction in wild type and transgenic tomato. Protein changes in both inoculated and apical leaves were revealed using two-dimensional gel electrophoresis (2-DE) coupled to differential in gel electrophoresis (DIGE) technology. A total of 2084 spots were detected, and 50 differentially expressed proteins were identified by nanoscale liquid chromatographic-electrospray ionization-ion trap-tandem mass spectrometry (nLC-ESI-IT-MS/MS). The majority of these proteins were related to photosynthesis (38%), primary metabolism (18%), and defense activity (14%) and demonstrated to be actively down regulated by CMV in infected leaves. Moreover, our analysis revealed that asymptomatic apical leaves of transgenic inoculated plants had no protein profile alteration as compared to control wild type uninfected plants demonstrating that virus infection is confined to the inoculated leaves and systemic spread is hindered by the CMV coat protein (CP)-specific scFv G4 molecules. Our work is the first comparative study on compatible plant-virus interactions between engineered immunoprotected and susceptible wild type tomato plants, contributing to the understanding of antibody-mediated disease resistance mechanisms.

  11. Plant perception and response to the signal in gravity resistance

    Science.gov (United States)

    Hoson, Takayuki; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Zhang, Yan; Otomi, Yasuhiro; Hashimoto, Takashi; Iida, Hidetoshi

    2012-07-01

    Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, distinct from gravitropism. Plants increase the rigidity of their cell walls in the final step of gravity resistance. We studied cellular events leading to or related to the cell wall changes under hypergravity conditions produced by centrifugation and under microgravity conditions in space. The involvement of mechanosensitive ion channels (mechanoreceptors) in signal perception in gravity resistance has been suggested by experiments with inhibitors. As a candidate for the mechanoreceptor, we identified MCA1 and MCA2 in Arabidopsis. mca-null and MCA-overexpressing seedlings were normal in growth in the dark at 1 g. However, suppression by hypergravity of elongation growth was reduced in hypocotyls of mca-null seedlings. On the contrary, MCA-overexpressing seedlings were hypersensitive to hypergravity. These results suggest that MCAs act as the mechanoreceptor in signal perception of gravity resistance. Cortical microtubules play an essential role in maintenance of normal growth phenotype under hypergravity conditions. In Space Seed experiment in the Kibo Module (PI: S. Kamisaka), we examined the effects of microgravity on growth phenotypes of Arabidopsis tubulin mutant, tua6. Inflorescences of the mutant emerged earlier and elongated rapidly under microgravity conditions than under on-orbit or ground 1 g conditions. Also, the inflorescences grown under microgravity conditions showed higher cell wall extensibilities than the controls. The tubulin mutant thus grew and developed more or less normally under microgravity conditions, supporting the principal role of microtubules also in plant resistance to 1 g gravity. On the other hand, the cellular osmotic properties, as well as the cell wall properties, are important factors determining the rigidity of plant body. Azuki bean epicotyls were capable of maintaining osmoregulation even under hypergravity

  12. Role of Elicitors in Inducing Resistance in Plants against Pathogen Infection: A Review.

    Science.gov (United States)

    Thakur, Meenakshi; Sohal, Baldev Singh

    2013-01-01

    Disease control is largely based on the use of fungicides, bactericides, and insecticides-chemical compounds toxic to plant invaders, causative agents, or vectors of plant diseases. However, the hazardous effect of these chemicals or their degradation products on the environment and human health strongly necessitates the search for new, harmless means of disease control. There must be some natural phenomenon of induced resistance to protect plants from disease. Elicitors are compounds, which activate chemical defense in plants. Various biosynthetic pathways are activated in treated plants depending on the compound used. Commonly tested chemical elicitors are salicylic acid, methyl salicylate, benzothiadiazole, benzoic acid, chitosan, and so forth which affect production of phenolic compounds and activation of various defense-related enzymes in plants. Their introduction into agricultural practice could minimize the scope of chemical control, thus contributing to the development of sustainable agriculture. This paper chiefly highlights the uses of elicitors aiming to draw sufficient attention of researchers to the frontier research needed in this context.

  13. The rising threat of fungicide resistance in plant pathogenic fungi: Botrytis as a case study.

    Science.gov (United States)

    Hahn, Matthias

    2014-10-01

    The introduction of site-specific fungicides almost 50 years ago has revolutionized chemical plant protection, providing highly efficient, low toxicity compounds for control of fungal diseases. However, it was soon discovered that plant pathogenic fungi can adapt to fungicide treatments by mutations leading to resistance and loss of fungicide efficacy. The grey mould fungus Botrytis cinerea, a major cause of pre- and post-harvest losses in fruit and vegetable production, is notorious as a 'high risk' organism for rapid resistance development. In this review, the mechanisms and the history of fungicide resistance in Botrytis are outlined. The introduction of new fungicide classes for grey mould control was always followed by the appearance of resistance in field populations. In addition to target site resistance, B. cinerea has also developed a resistance mechanism based on drug efflux transport. Excessive spraying programmes have resulted in the selection of multiresistant strains in several countries, in particular in strawberry fields. The rapid erosion of fungicide activity against these strains represents a major challenge for the future of fungicides against Botrytis. To maintain adequate protection of intensive cultures against grey mould, strict implementation of resistance management measures are required as well as alternative strategies with non-chemical products.

  14. A plant Bcl-2-associated athanogene is proteolytically activated to confer fungal resistance

    Directory of Open Access Journals (Sweden)

    Mehdi Kabbage

    2016-04-01

    Full Text Available The Bcl-2-associated athanogene (BAG family is a multifunctional group of proteins involved in numerous cellular functions ranging from apoptosis to tumorigenesis. These proteins are evolutionarily conserved and encode a characteristic region known as the BAG domain. BAGs function as adapter proteins forming complexes with signaling molecules and molecular chaperones. In humans, a role for BAG proteins has been suggested in tumor growth, HIV infection, and neurodegenerative diseases; as a result, the BAGs are attractive targets for therapeutic interventions, and their expression in cells may serve as a predictive tool for disease development. The Arabidopsis genome contains seven homologs of BAG family proteins (Figure 1, including four with a domain organization similar to animal BAGs (BAG1-4. The remaining three members (BAG5-7 contain a predicted calmodulin-binding motif near the BAG domain, a feature unique to plant BAG proteins that possibly reflects divergent mechanisms associated with plant-specific functions. As reported for animal BAGs, plant BAGs also regulate several stress and developmental processes (Figure 2. The recent article by Li et al. focuses on the role of BAG6 in plant innate immunity. This study shows that BAG6 plays a key role in basal plant defense against fungal pathogens. Importantly, this work further shows that BAG6 is proteolytically activated to induce autophagic cell death and resistance in plants. This finding underscores the importance of proteases in the execution of plant cell death, yet little is known about proteases and their substrates in plants.

  15. Antibiotic-resistant soil bacteria in transgenic plant fields.

    Science.gov (United States)

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy M; Simonet, Pascal

    2008-03-11

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-year culture of the transgenic Bt176 corn, which has a blaTEM marker gene, could have had on the soil bacterial community. The bla gene encoding resistance to ampicillin belongs to the beta-lactam antibiotic family, which is widely used in medicine but is readily compromised by bacterial antibiotic resistance. Our results indicate that soil bacteria are naturally resistant to a broad spectrum of beta-lactam antibiotics, including the third cephalosporin generation, which has a slightly stronger discriminating effect on soil isolates than other cephalosporins. These high resistance levels for a wide range of antibiotics are partly due to the polymorphism of bla genes, which occur frequently among soil bacteria. The blaTEM116 gene of the transgenic corn Bt176 investigated here is among those frequently found, thus reducing any risk of introducing a new bacterial resistance trait from the transgenic material. In addition, no significant differences were observed in bacterial antibiotic-resistance levels between transgenic and nontransgenic corn fields, although the bacterial populations were different.

  16. Molecular and physiological strategies to increase aluminum resistance in plants.

    Science.gov (United States)

    Inostroza-Blancheteau, Claudio; Rengel, Zed; Alberdi, Miren; de la Luz Mora, María; Aquea, Felipe; Arce-Johnson, Patricio; Reyes-Díaz, Marjorie

    2012-03-01

    Aluminum (Al) toxicity is a primary limitation to plant growth on acid soils. Root meristems are the first site for toxic Al accumulation, and therefore inhibition of root elongation is the most evident physiological manifestation of Al toxicity. Plants may resist Al toxicity by avoidance (Al exclusion) and/or tolerance mechanisms (detoxification of Al inside the cells). The Al exclusion involves the exudation of organic acid anions from the root apices, whereas tolerance mechanisms comprise internal Al detoxification by organic acid anions and enhanced scavenging of free oxygen radicals. One of the most important advances in understanding the molecular events associated with the Al exclusion mechanism was the identification of the ALMT1 gene (Al-activated malate transporter) in Triticum aestivum root cells, which codes for a plasma membrane anion channel that allows efflux of organic acid anions, such as malate, citrate or oxalate. On the other hand, the scavenging of free radicals is dependent on the expression of genes involved in antioxidant defenses, such as peroxidases (e.g. in Arabidopsis thaliana and Nicotiana tabacum), catalases (e.g. in Capsicum annuum), and the gene WMnSOD1 from T. aestivum. However, other recent findings show that reactive oxygen species (ROS) induced stress may be due to acidic (low pH) conditions rather than to Al stress. In this review, we summarize recent findings regarding molecular and physiological mechanisms of Al toxicity and resistance in higher plants. Advances have been made in understanding some of the underlying strategies that plants use to cope with Al toxicity. Furthermore, we discuss the physiological and molecular responses to Al toxicity, including genes involved in Al resistance that have been identified and characterized in several plant species. The better understanding of these strategies and mechanisms is essential for improving plant performance in acidic, Al-toxic soils.

  17. "Active" refuges can inhibit the evolution of resistance in insects towards transgenic insect-resistant plants.

    Science.gov (United States)

    Pittendrigh, Barry R; Gaffney, Patrick J; Huesing, Joseph E; Onstad, David W; Roush, Richard T; Murdock, Larry L

    2004-12-21

    Negative cross-resistance (NCR) toxins that hitherto have not been thought to have practical uses may indeed be useful in the management of resistance alleles. Practical applications of NCR for pest management have been limited (i) by the scarcity of high toxicity NCR toxins among pesticides, (ii) by the lack of systematic methodologies to discover and develop such toxins, as well as (iii) by the lack of deployment tactics that would make NCR attractive. Here we present the concept that NCR toxins can improve the effectiveness of refuges in delaying the evolution of resistance by herbivorous insect pests to transgenic host plants containing insecticidal toxins. In our concept, NCR toxins are deployed in the refuge, and thus are physically separated from the transgenic plants containing the primary plant-protectant gene (PPPG) encoding an insecticidal toxin. Our models show: (i) that use of NCR toxins in the refuge dramatically delays the increase in the frequency of resistance alleles in the insect population; and (ii) that NCR toxins that are only moderately effective in killing insects resistant to the PPPG can greatly improve the durability of transgenic insecticidal toxins. Moderately toxic NCR toxins are more effective in minimizing resistance development in the field when they are deployed in the refuge than when they are pyramided with the PPPG. We explore the potential strengths and weaknesses of deploying NCR toxins in refuges.

  18. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance.

    Science.gov (United States)

    Manosalva, Patricia; Manohar, Murli; von Reuss, Stephan H; Chen, Shiyan; Koch, Aline; Kaplan, Fatma; Choe, Andrea; Micikas, Robert J; Wang, Xiaohong; Kogel, Karl-Heinz; Sternberg, Paul W; Williamson, Valerie M; Schroeder, Frank C; Klessig, Daniel F

    2015-07-23

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture.

  19. Evaluation of plant resistance inducers on different winter soft wheat cultivars against Septoria leaf blotch.

    Science.gov (United States)

    Ors, M; Siah, A; Randoux, B; Selim, S; Boizet, F; Couleaud, G; Maumene, C; Halama, P; Reignault, Ph

    2012-01-01

    Septoria tritici blotch (STB) caused by Mycosphaerella graminicola (anamorph: Zymoseptoria tritici) is one of the most devastating foliar diseases on bread wheat (Triticum aestivum L.). Because of the emergence of fungal strains highly resistant to mainly used fungicides and the deleterious impacts of these fungicides on the environment, development of alternative control strategies to protect wheat crops against STB is needed. The induction of plant resistance by elicitors is likely to be a helpful alternative. Our study aims at characterizing the efficiency of potential resistance inducers towards STB in three bread wheat cultivars differing in their resistance levels to the pathogen: Alixan (susceptible), Premio (moderately resistant) and Altigo (resistant). These cultivars were inoculated under controlled and semi-controlled conditions with the pathogenic M. graminicolo strain T01193 in order to assess the protective effect of three potential resistance inducers against the disease. Moreover, the direct antifungal effect bf these products was evaluated in vitro at different concentrations in order to verify their potential biocide activity. Furthermore, cytological analyses were performed in order to determine the effects of these products on the fungal infection process and to compare these effects among the three wheat cultivars. Finally, reactive oxygen species metabolism was investigated in the three cultivars during their interaction with T01193 by measuring peroxidase activity.

  20. Controversy Associated With the Common Component of Most Transgenic Plants – Kanamycin Resistance Marker Gene

    Directory of Open Access Journals (Sweden)

    Srećko Jelenić

    2003-01-01

    Full Text Available Plant genetic engineering is a powerful tool for producing crops resistant to pests, diseases and abiotic stress or crops with improved nutritional value or better quality products. Currently over 70 genetically modified (GM crops have been approved for use in different countries. These cover a wide range of plant species with significant number of different modified traits. However, beside the technology used for their improvement, the common component of most GM crops is the neomycin phosphotransferase II gene (nptII, which confers resistance to the antibiotics kanamycin and neomycin. The nptII gene is present in GM crops as a marker gene to select transformed plant cells during the first steps of the transformation process. The use of antibiotic-resistance genes is subject to controversy and intense debate, because of the likelihood that clinical therapy could be compromised due to inactivation of the oral dose of the antibiotic from consumption of food derived from the transgenic plant, and because of the risk of gene transfer from plants to gut and soil microorganisms or to consumer’s cells. The present article discusses these possibilities in the light of current scientific knowledge.

  1. Study of the Adult-Plant Resistance at Different Growth Stages to Stripe Rust in Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHAO Huan-huan; R P Singh; J Huerta-Espino; YANG Zuo-min; SUN Qi-xin

    2005-01-01

    Components of resistance were investigated for five adult-plant resistant (APR) wheat (Triticum aestivum) cultivars at six growth stages and two temperatures in the greenhouse, and disease progress in a field trial. Chinese cultivar Chuanyu 12displayed high to intermediate infection type (IT) in the greenhouse but was highly resistant in the field. Weebill showed an intermediate IT in the greenhouse and also in the field. Chpaio, Tukuru and Saar, known to carry combinations of Yr18and 2-3 additional minor genes, were highly resistant in both experiments. Greenhouse experiments indicated that the lower IT of APR cultivars initiated at tillering stage. Latent periods (LP) for APR cultivars were generally longer as the growth stage progressed. We conclude that APR to stripe rust can be best characterized in field trials although significant correlations are seen between field severity and IT and LP measured in the greenhouse.

  2. Exploring antibiotic resistance genes and metal resistance genes in plasmid metagenomes from wastewater treatment plants.

    Science.gov (United States)

    Li, An-Dong; Li, Li-Guan; Zhang, Tong

    2015-01-01

    Plasmids operate as independent genetic elements in microorganism communities. Through horizontal gene transfer (HGT), they can provide their host microorganisms with important functions such as antibiotic resistance and heavy metal resistance. In this study, six metagenomic libraries were constructed with plasmid DNA extracted from influent, activated sludge (AS) and digested sludge (DS) of two wastewater treatment plants (WWTPs). Compared with the metagenomes of the total DNA extracted from the same sectors of the wastewater treatment plant, the plasmid metagenomes had significantly higher annotation rates, indicating that the functional genes on plasmids are commonly shared by those studied microorganisms. Meanwhile, the plasmid metagenomes also encoded many more genes related to defense mechanisms, including ARGs. Searching against an antibiotic resistance genes (ARGs) database and a metal resistance genes (MRGs) database revealed a broad-spectrum of antibiotic (323 out of a total 618 subtypes) and MRGs (23 out of a total 23 types) on these plasmid metagenomes. The influent plasmid metagenomes contained many more resistance genes (both ARGs and MRGs) than the AS and the DS metagenomes. Sixteen novel plasmids with a complete circular structure that carried these resistance genes were assembled from the plasmid metagenomes. The results of this study demonstrated that the plasmids in WWTPs could be important reservoirs for resistance genes, and may play a significant role in the horizontal transfer of these genes.

  3. Pesticide productivity, host-plant resistance and productivity in China

    OpenAIRE

    Widawsky, David; Rozelle, Scott; Jin, Songqing; Huang, Jikun

    1998-01-01

    Pesticides are used as the primary method of pest control in Asian rice production. Conditions in China have led to demand for high and increasing rice yields, resulting in intensive cultivation and adoption of fertilizer responsive varieties. The consequence has been widespread pest infestations. Many studies have estimated pesticide productivity, but few have estimated the productivity of alternative methods of pest control, namely host-plant resistance. None have estimated the substitutabi...

  4. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demaneche, S.; Sanguin, H.; Pote, J.; Navarro, Elisabeth; Bernillon, D.; Mavingui, P.; Wildi, W.; Vogel, T M; Simonet, P

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 110-successive-y...

  5. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy M.; Simonet, Pascal

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-ye...

  6. Antibiotic-resistant soil bacteria in transgenic plant fields

    OpenAIRE

    Demanèche, Sandrine; Sanguin, Hervé; Poté, John; Navarro, Elisabeth; Bernillon, Dominique; Mavingui, Patrick; Wildi, Walter; Vogel, Timothy,; Simonet, Pascal

    2008-01-01

    Understanding the prevalence and polymorphism of antibiotic resistance genes in soil bacteria and their potential to be transferred horizontally is required to evaluate the likelihood and ecological (and possibly clinical) consequences of the transfer of these genes from transgenic plants to soil bacteria. In this study, we combined culture-dependent and -independent approaches to study the prevalence and diversity of bla genes in soil bacteria and the potential impact that a 10-successive-y...

  7. Arabidopsis PED2 positively modulates plant drought stress resistance

    Institute of Scientific and Technical Information of China (English)

    Haitao Shi; Tiantian Ye; Fan Yang; Zhulong Chan

    2015-01-01

    Abscisic acid (ABA) is an important phytohormone that functions in seed germination, plant development, and multiple stress responses. Arabidopsis Peroxisome defective 2 (AtPED2) (also known as AtPEXOXIN14, AtPEX14), is involved in the intracellular transport of thiolase from the cytosol to glyoxysomes, and perosisomal matrix protein import in plants. In this study, we assigned a new role for AtPED2 in drought stress resistance. The transcript level of AtPED2 was down-regulated by ABA and abiotic stress treatments. AtPED2 knockout mutants were insensitive to ABA-mediated seed germination, primary root elongation, and stomatal response, while AtPED2 over-expressing plants were sensitive to ABA in comparison to wide type (WT). AtPED2 also positively regulated drought stress resistance, as evidenced by the changes of water loss rate, electrolyte leakage, and survival rate. Notably, AtPED2 positively modulated expression of several stress-responsive genes (RAB18, RD22, RD29A, and RD29B), positively affected underlying antioxidant enzyme activities and negatively regulated reactive oxygen species (ROS) level under drought stress conditions. Moreover, multiple carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines were also positively regulated by AtPED2. Taken together, these results indicated a positive role for AtPED2 in drought resistance, through modulation of stress-responsive genes expression, ROS metabolism, and metabolic homeostasis, at least partially.

  8. Resistance induced component of management of diseases of grapevine

    Directory of Open Access Journals (Sweden)

    Jusciélio Barbosa

    2009-08-01

    Full Text Available The use of induced resistance presents as a viable alternative in the management of diseases of the vine. Accordingly, the objective of this study was to evaluate the efficiency of Agro Mos® and potassium phosphite in controlling diseases of grapevine under field conditions in the Valley San Francisco. O test was conducted under field conditions in the experimental area IFSertão Pernambucano, Petrolina, PE, using the cultivar Petit Sirah. The experimental design was in randomized blocks, composed of five treatments and five replicates: T1 - control; T2 - Cabrio Top® - CT (2kg ha-1; T3 - Agro Mos® - AM (3mL L-1; T4 - Fosfito de potássio - FP (4mL L-1; T5 - Agro Mos® - AM (3mL L-1 interleaved with the fungicide Cabrio Top® - CT (2kg ha-1. Each plot consisted of eight plants. Data were subjected to analysis of variance and averages compared by Tukey test at 5%. Conditions in which the experiment was developed, the use of potassium phosphite and Agro-Mos® promoted a significant reduction in the incidence of Plasmopara viticola and Uncinula necator.Key-words: resistance induced, Plasmopara viticola, Uncinula necator.

  9. Epistatic adult plant resistance in wheat to stem rust cosegregates with Sr12 seedling resistance

    Science.gov (United States)

    Wheat adult plant resistance (APR) to stem rust is desirable. Researchers have characterized the inheritance of APR in cultivar Thatcher as complex. In order to identify the loci providing APR in Thatcher, we evaluated 160 RILs derived from Thatcher/McNeal for stem rust reaction in the field in Keny...

  10. Antimicrobial activity of medicinal plants used by aborigines of Kalahandi, Orissa, India against multidrug resistant bacteria

    Institute of Scientific and Technical Information of China (English)

    Debasmita Dubey; Mahesh C Sahu; Shakti Rath; Bimoch Projna Paty; Nagen K Debata; Rabindra N Padhy

    2012-01-01

    Objective: To evaluate the antimicrobial potency of 20 non-edible and/or poisonous plants used by an aborigine tribe (Kandha) of Kalahandi district for infectious diseases. Methods: Over a period of 5 months from two hospitals, 10 pathogenic bacteria (Staphylococcus aureus (S. aureus), Acinetobacter sp., Citrobacter freundii (C. freundii), Chromobacterium violeceum (C. violeceum),Escherichia coli (E. coli), Klebsiella sp., Proteus sp., Pseudomonas aeruginosa (P. aeruginosa) Salmonella typhi (S. typhi) and Vibrio cholerae (V. cholerae) were isolated to pure axenic cultures from clinical samples. Water and ethanolic extracts of leaves and barks were concentrated before monitoring antimicrobial activity by agar-well diffusion method. Results: All bacterial strains isolated were multidrug resistant. Ethanolic extract of most plants had effective antimicrobial activity against all the isolated multidrug resistant bacteria. Plants, Anthocephalus cadamba (A. cadamba) and Pterocarpus santalinus (P. santalinus) had antibacterial effect on all used bacteria. Water extract of several plants too had effective antimicrobial activity for all bacteria used. Effective in vitro control of MDR strains of Acinetobacter sp., C. freundii, Proteus sp. and P. aeruginosa, the most potential urinary tract infection causing organisms by plant extracts of all major plant used herein is recorded. MDR C. violaceum isolated from skin lesions was found to be resistant to imipenem, piperacillin-tazobactam and amoxyclav and was found sensitive to 13 plant extracts. Conclusion: Effective in vitro control of MDR strains of Acinetobacter sp.,C. freundii, Proteus sp. and P. aeruginosa; enteropathogenic bacteria, E. coli, S. typhi, Klebsiella sp. and V. cholerae were found to be well controlled by all plant extracts used.

  11. An Arabidopsis thaliana ABC transporter that confers kanamycin resistance in transgenic plants does not endow resistance to Escherichia coli

    OpenAIRE

    Burris, Kellie; Mentewab, Ayalew; Ripp, Steven; Stewart, C. Neal

    2007-01-01

    Summary Concerns have been raised about potential horizontal gene transfer (HGT) of antibiotic resistance markers (ARMs) from transgenic plants to bacteria of medical and environmental importance. All ARMs used in transgenic plants have been bacterial in origin, but it has been recently shown that an Arabidopsis thaliana ABC transporter, Atwbc19, confers kanamycin resistance when overexpressed in transgenic plants. Atwbc19 was evaluated for its ability to transfer kanamycin resistance to Esch...

  12. Host Resistance and Temperature-Dependent Evolution of Aggressiveness in the Plant Pathogen Zymoseptoria tritici

    Directory of Open Access Journals (Sweden)

    Fengping Chen

    2017-06-01

    Full Text Available Understanding how habitat heterogeneity may affect the evolution of plant pathogens is essential to effectively predict new epidemiological landscapes and manage genetic diversity under changing global climatic conditions. In this study, we explore the effects of habitat heterogeneity, as determined by variation in host resistance and local temperature, on the evolution of Zymoseptoria tritici by comparing the aggressiveness development of five Z. tritici populations originated from different parts of the world on two wheat cultivars varying in resistance to the pathogen. Our results show that host resistance plays an important role in the evolution of Z. tritici. The pathogen was under weak, constraining selection on a host with quantitative resistance but under a stronger, directional selection on a susceptible host. This difference is consistent with theoretical expectations that suggest that quantitative resistance may slow down the evolution of pathogens and therefore be more durable. Our results also show that local temperature interacts with host resistance in influencing the evolution of the pathogen. When infecting a susceptible host, aggressiveness development of Z. tritici was negatively correlated to temperatures of the original collection sites, suggesting a trade-off between the pathogen’s abilities of adapting to higher temperature and causing disease and global warming may have a negative effect on the evolution of pathogens. The finding that no such relationship was detected when the pathogen infected the partially resistant cultivars indicates the evolution of pathogens in quantitatively resistant hosts is less influenced by environments than in susceptible hosts.

  13. Germplasm Modification and Its Potential for Finding New Sources of Resistance to Diseases

    OpenAIRE

    Richard E. Litz

    1986-01-01

    In vitro procedures are playing a major role in plant breeding. Embryo rescue, either through the culture of excised embryos derived from incompatible crosses or by means of ovule culture, has been a standard procedure for the introgression of genes conferring disease resistance into economically important plants. Somatic hybridization (i.e., protoplast fusion) has also been demonstrated to have some potential in obtaining hybrids that result from very wide interspecific and intergeneric cros...

  14. Cytogenetic Mapping of Disease Resistance Genes and Analysis of Their Distribution Features on Chromosomes in Maize

    Institute of Scientific and Technical Information of China (English)

    Li Li-jia; Song Yun-chun

    2003-01-01

    Cytogenetic maps of four clusters of disease resistance genes were generated by ISH of the two RFLP markers tightly linked to and flanking each of maize resistance genes and the cloned resistance genes from other plant species onto maize chromosomes, combining with data published before. These genes include Helminthosporium turcium Pass resistance genes Ht1, Htn1 and Ht2, Helminthosporium maydis Nisik resistance genes Rhm1 and Rhm2, maize dwarf mosaic virus resistance gene Mdm1, wheat streak mosaic virus resistance gene Wsm1, Helminthosporium carbonum ULLstrup resistance gene Hml and the cloned Xanthomonas oryzae pv. Oryzae resistance gene Xa21 of rice, Cladosporium fulvum resistance genes Cf-9 and Cf-2.1 of tomato,and Pseudomonas syringae resistance gene RPS2 of Arabidopsis. Most of the tested disease resistance genes located on the four chromosomes, i.e., chromosomes1, 3, 6 and 8, and they closely distributed at the interstitial regions of these chromosomal long arms with percentage distances ranging 31.44(±3.72)-72.40(±3.25) except for genes Rhm1, Rhm2, Mdm1 and Wsm1 which mapped on the satellites of the short arms of chromosome6. It showed that the tested RFLP markers and genes were duplicated or triplicated in maize genome. Homology and conservation of disease resistance genes among species, and relationship between distribution features and functions of the genes were discussed. The results provide important scientific basis for deeply understanding structure and function of disease resistance genes and breeding in maize.

  15. RNAi-derived field resistance to Cassava brown streak disease persists across the vegetative cropping cycle.

    Science.gov (United States)

    Odipio, John; Ogwok, Emmanuel; Taylor, Nigel J; Halsey, Mark; Bua, Anton; Fauquet, Claude M; Alicai, Titus

    2014-01-01

    A confined field trial was established to determine durability of RNAi-mediated resistance to Cassava brown streak disease (CBSD). Stem cuttings were obtained from field-grown cassava plants of cv 60444 transgenic for construct p718, consisting of an 894 bp inverted repeat sequence from the Ugandan Cassava brown streak virus (UCBSV) coat protein. Plants were established from three transgenic lines previously shown to provide complete resistance to UCBSV and differing levels of protection to the non-homologous virus species Cassava brown streak virus (CBSV), and grown for 11 months. CBSD symptoms were observed on shoots and storage roots of all non-transgenic cv 60444 control plants and transgenic lines p718-002 and p718-005, but not on p718-001. RT-PCR diagnostic showed tissues of plant lines p718-002 and p718-005 to be infected with CBSV, but free of UCBSV. All leaves and roots of p718-001 plants were to carry no detectable levels of either pathogen. Plants of cv 60444 in this field trial showed severe cassava mosaic disease symptoms, indicating that presence of replicating geminiviruses did not cause significant suppression of RNAi-mediated resistance to CBSD. Resistance to CBSD across a vegetative cropping cycle confirms earlier field data, and provides an important step in proof of concept for application of RNAi technology to control of CBSD under conditions encountered in farmers' fields.

  16. Theoretical model of the three-dimensional structure of a disease resistance gene homolog encoding resistance protein in Vigna mungo.

    Science.gov (United States)

    Basak, Jolly; Bahadur, Ranjit P

    2006-10-01

    Plant disease resistance (R) genes, the key players of innate immunity system in plants encode 'R' proteins. 'R' protein recognizes product of avirulance gene from the pathogen and activate downstream signaling responses leading to disease resistance. No three dimensional (3D) structural information of any 'R' proteins is available as yet. We have reported a 'R' gene homolog, the 'VMYR1', encoding 'R' protein in Vigna mungo. Here, we describe the homology modeling of the 'VMYR1' protein. The model was created by using the 3D structure of an ATP-binding cassette transporter protein from Vibrio cholerae as a template. The strategy for homology modeling was based on the high structural conservation in the superfamily of P-loop containing nucleoside triphosphate hydrolase in which target and template proteins belong. This is the first report of theoretical model structure of any 'R' proteins.

  17. Genomic tools for developing markers for postharvest disease resistance in Rosaceae fruit crops

    Science.gov (United States)

    A wealth of new plant genomic information and molecular tools have been developed over the past ten years and now the challenge is to learn how to apply this information to address critical production problems, such as disease resistance and abiotic stress tolerance. Malus sieversii, an apple speci...

  18. Genotype x environment interaction and growth stability of several elm clones resistant to Dutch elm disease

    Science.gov (United States)

    Alberto Santini; Francesco Pecori; Alessia L. Pepori; Luisa Ghelardini

    2012-01-01

    The elm breeding program carried out in Italy at the Institute of Plant Protection - Consiglio Nazionale delle Ricercje (CNR) during the last 40 years aimed to develop Dutch elm disease (DED)-resistant elm selections specific to the Mediterranean environment. The need for genotypes adapted to Mediterranean conditions was evident from the poor performance of the Dutch...

  19. Behaviour of the disease resistance gene Asc in protoplasts of Lycopersicon esculentum mill

    NARCIS (Netherlands)

    Moussatos, V.; Witsenboer, H.; Hille, J.; Gilchrist, D.

    1993-01-01

    Action of Asc, a single dominant Mendelian gene controlling disease response at the whole plant level, was detected at the level of individual cells. Protoplasts, freshly isolated from resistant (Asc/Asc) and susceptible (asc/asc) tomato isolines, were differentially sensitive to AAL toxin as observ

  20. Climate change effects on plant disease: Genomes to ecosystems

    OpenAIRE

    Garrett, Karen A.; Dendy, S.P.; Frank, E.E.; Rouse, M. N.; Travers, S.E.

    2006-01-01

    We have reviewed the potential effects of climate change on plant disease, considering processes within plants as well as larger scale processes. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  1. Climate change effects on plant disease: Genomes to ecosystems

    OpenAIRE

    Garrett, Karen A.; Dendy, S.P.; Frank, E.E.; Rouse, M. N.; Travers, S.E.

    2006-01-01

    We have reviewed the potential effects of climate change on plant disease, considering processes within plants as well as larger scale processes. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  2. Induce systemic resistance in lupine against root rot diseases.

    Science.gov (United States)

    Ali, Abeer A; Ghoneem, K M; El-Metwally, M A; Abd El-Hai, K M

    2009-02-01

    Root rot caused by soil borne pathogenic fungi is the most sever disease attacks lupine plants. Isolation trials from diseased plants in some areas of Dakahlia Province (Egypt) was carried out. Rhizoctonia solani and Fusarium solani proved to be the most dominant isolates. Meanwhile, Fusarium oxysporum and Sclerotium rolfsii were less frequent. Efficacies of some plant resistance elicitors viz.: chitosan (CHI), Salicylic Acid (SA) and hydroquinone (HQ) in comparing to the fungicide Rhizolex T-50 as seed treatments showed significant reduction in the fungal growth in vitro. Chitosan at 8 g L(-1) and fungicide completely inhibited the growth of all isolated fungi, while SA at 1.4 g L(-1) and HQ at 1.2 g L(-1) inhibited the growth of Fusarium solani and F. oxysporum, respectively. The greenhouse experiments showed that S. rolfesii (No. 6) and R. solani (No. 2) followed by F. solani (No. 5) and F. oxysporum (No. 9) were the most aggressive root rot fungi. Soaking susceptible lupine seeds (Giza 1) in each one of the three selected elicitors showed a significant reduction in seedlings mortality. CHI at 8 g L(-1) was superior in increasing the percentage of healthy plants to record 72.5, 80.9, 62.7and 64.3%, when seeds were grown in soil infested with of F. solani, F. oxysporum, R. solani and S. rolfesii, respectively. These results were confirmed under field conditions in two different locations i.e., Tag El-Ezz and El-Serow Research Stations. CHI 8 g L(-1) proved to be the best elicitor after fungicide, in reducing lupine root rot disease. It showed 41 and 60% reduction in the plants mortality comparing to 56.37 and 69.13% in case of Rhizolex-T in Tag El-Ezz and El-Serow locations, respectively. The treatments were accompanied with a significant increase in lupine growth parameters, yield components and physiological aspects. Application of CHI at 8 g L(-1) or HQ at 1.2 g L(-1) was the most potent in this respect as compared to check treatment.

  3. SENSITIVE RESPONSE AND RESISTANCE TO BERY DISEASE ...

    African Journals Online (AJOL)

    AISA

    Key words : Colletotrichum kahawae, Coffee, resistant, susceptible, Kenya. RESUME. SENSIBILITE ET .... when further changes were minimal. The experiments were ..... to the ability of the fungus to overcome the resistance mechanisms, or ...

  4. Differential disease resistance response in the barley necrotic mutant nec1

    Directory of Open Access Journals (Sweden)

    Kunga Laura

    2011-04-01

    Full Text Available Abstract Background Although ion fluxes are considered to be an integral part of signal transduction during responses to pathogens, only a few ion channels are known to participate in the plant response to infection. CNGC4 is a disease resistance-related cyclic nucleotide-gated ion channel. Arabidopsis thaliana CNGC4 mutants hlm1 and dnd2 display an impaired hypersensitive response (HR, retarded growth, a constitutively active salicylic acid (SA-mediated pathogenesis-related response and elevated resistance against bacterial pathogens. Barley CNGC4 shares 67% aa identity with AtCNGC4. The barley mutant nec1 comprising of a frame-shift mutation of CNGC4 displays a necrotic phenotype and constitutively over-expresses PR-1, yet it is not known what effect the nec1 mutation has on barley resistance against different types of pathogens. Results nec1 mutant accumulated high amount of SA and hydrogen peroxide compared to parental cv. Parkland. Experiments investigating nec1 disease resistance demonstrated positive effect of nec1 mutation on non-host resistance against Pseudomonas syringae pv. tomato (Pst at high inoculum density, whereas at normal Pst inoculum concentration nec1 resistance did not differ from wt. In contrast to augmented P. syringae resistance, penetration resistance against biotrophic fungus Blumeria graminis f. sp. hordei (Bgh, the causal agent of powdery mildew, was not altered in nec1. The nec1 mutant significantly over-expressed race non-specific Bgh resistance-related genes BI-1 and MLO. Induction of BI-1 and MLO suggested putative involvement of nec1 in race non-specific Bgh resistance, therefore the effect of nec1on mlo-5-mediated Bgh resistance was assessed. The nec1/mlo-5 double mutant was as resistant to Bgh as Nec1/mlo-5 plants, suggesting that nec1 did not impair mlo-5 race non-specific Bgh resistance. Conclusions Together, the results suggest that nec1 mutation alters activation of systemic acquired resistance

  5. Short communication. Inheritance of yield, yield components and resistance to major diseases in Sesamum indicum L

    Energy Technology Data Exchange (ETDEWEB)

    El-Bramaway, M. A. S.; Shaban, W. I.

    2008-07-01

    Field experiments were conducted over 2005 and 2006 to study the gene action associated with yield and ten yield components, as well as resistance Fusarium wilt, charcoal rot and Alternaria leaf spot, in 6x6 half-diallel sesame progenies (F1). Highly significant differences among the 15 F1s and their six parents were detected with respect to all the investigated traits. A preponderance of non-additive genetic variance was seen for all the studied traits, except for days to maturity and resistance to Alternaria leaf spot. Ten traits showed over dominance. Recessive alleles were predominantly involved in fruiting branches plant-1, capsules plant-1 and single plant yield. The distribution of genes with positive and negative effects were symmetrical or nearly symmetrical with respect to 1000-seed weight, charcoal rot disease resistance, fruiting branches plant-1, capsules plant-1, single plant yield, and oil content. The parents possessed mostly negative genes in dominant form with respect to capsules plant-1, 1000-seed weight, oil content, and resistance to charcoal rot and Alternaria leaf spot; positive genes in recessive form were observed for the rest of the studied traits. Given the gene action observed, bi parental mating or diallel selective mating and heterosis breeding is suggested for the improvement of sesame. (Author) 24 refs.

  6. Biomarkers and mechanisms of natural disease resistance in dairy cows

    NARCIS (Netherlands)

    Altena, van S.E.C.

    2016-01-01

    The aim of this thesis was to define and test biomarkers for disease resistance in dairy cows and to determine the underlying mechanism in natural disease resistance. The health status of the cows is an important issue in dairy farming. Due to the mandatory reduction in the use of antibiotics, alter

  7. Modeling deployment of Pierce’s disease resistant grapevines

    Science.gov (United States)

    Deployment of Pierce’s disease resistant grapevines is a key solution to mitigating economic losses caused by Xylella fastidiosa. While Pierce’s disease resistant grapevines under development display mild symptoms and have lower bacterial populations than susceptible varieties, all appear to remain ...

  8. Working Towards Disease Resistance in Peanuts Through Biotechnology

    Science.gov (United States)

    Resistant cultivars are the most desirable approach to disease control in agriculture. Early and late leaf spot are the most important foliar diseases of peanut worldwide. Significant progress for leaf spot resistance in peanut can be achieved through biotechnology. The National Peanut Research ...

  9. Plant signalling components EDS1 and SGT1 enhance disease caused by the necrotrophic pathogen Botrytis cinerea.

    Science.gov (United States)

    El Oirdi, Mohamed; Bouarab, Kamal

    2007-01-01

    * Botrytis cinerea is a necrotrophic fungus that causes grey mould on a wide range of food plants, especially grapevine, tomato, soft fruits and vegetables. This disease brings about important economic losses in both pre- and postharvest crops. Successful protection of host plants against this pathogen is severely hampered by a lack of resistance genes in the hosts and the considerable phenotypic diversity of the fungus. * The aim of this study was to test whether B. cinerea manipulates the immunity-signalling pathways in plants to restore its disease. * We showed that B. cinerea caused disease in Nicotiana benthamiana through the activation of two plant signalling genes, EDS1 and SGT1, which have been shown to be essential for resistance against biotrophic pathogens; and more interestingly, virus-induced gene silencing of these two plant signalling components enhanced N. benthamiana resistance to B. cinerea. Finally, plants expressing the baculovirus antiapoptotic protein p35 were more resistant to this necrotrophic pathogen than wild-type plants. * This work highlights a new strategy used by B. cinerea to establish disease. This information is important for the design of strategies to improve plant pathogen resistance.

  10. Can vessel dimension explain tolerance toward fungal vascular wilt diseases in woody plants? Lessons from Dutch elm disease and esca disease in grapevine.

    Directory of Open Access Journals (Sweden)

    Jerome ePouzoulet

    2014-06-01

    Full Text Available This review illuminates key findings in our understanding of grapevine xylem resistance to fungal vascular wilt diseases. Grapevine (Vitis spp. vascular diseases such as esca, botryosphaeria dieback, and eutypa dieback, are caused by a set of taxonomically unrelated ascomycete fungi. Fungal colonization of the vascular system leads to a decline of the plant host because of a loss of the xylem function and subsequent decrease in hydraulic conductivity. Fungal vascular pathogens use different colonization strategies to invade and kill their host. Vitis vinifera cultivars display different levels of tolerance towards vascular diseases caused by fungi, but the plant defense mechanisms underlying those observations have not been completely elucidated. In this review, we establish a parallel between two vascular diseases, grapevine esca disease and Dutch elm disease, and argue that the former should be viewed as a vascular wilt disease. Plant genotypes exhibit differences in xylem morphology and resistance to fungal pathogens causing vascular wilt diseases. We provide evidence that the susceptibility of three commercial V. vinifera cultivars to esca disease is correlated to large vessel diameter. Additionally, we explore how xylem morphological traits related to water transport are influenced by abiotic factors, and how these might impact host tolerance of vascular wilt fungi. Finally, we explore the utility of this concept for predicting which V. vinifera cultivars are most vulnerable of fungal vascular wilt diseases and propose new strategies for disease management.

  11. The Role of Peroxidase Isozymes in Resistance to Wheat Stem Rust Disease 1

    Science.gov (United States)

    Seevers, P. M.; Daly, J. M.; Catedral, F. F.

    1971-01-01

    In common with other disease situations, rust-resistant wheat leaves show a large increase in peroxidase activity during infection. Peroxidase isozymes from healthy or infected lines of wheat (Triticum aestivum L.) near isogenic for resistance and susceptibility to race 56 of Puccinia graminis tritici were separated by gel electrophoresis and the activity of each was estimated by photometric scanning. In order to ensure that the activity of isozymes observed on gels reflected the changes found in peroxidase enzymes assayed spectrophotometrically in extracts, a study was made of extraction procedures, substrates, and reaction conditions for both types of enzyme measurements. Of the 14 isozymes detected in both healthy and infected leaves, increases in only 1 (isozyme 9) were associated consistently with the development of resistant disease reaction at 20 C. Additional evidence was obtained to show that this isozyme can account for the increased peroxidase activity observed in extracts from resistant plants. When plants with high induced peroxidase activity due to resistance at 20 C were treated with ethylene or transferred to 25 C, they reverted to complete susceptibility. However, the disease-induced activity of isozyme 9 did not fall. The data suggest that, in this case, the association of peroxidase with resistance was a consequence of, not a determinant in, resistance. PMID:16657797

  12. The role of peroxidase isozymes in resistance to wheat stem rust disease.

    Science.gov (United States)

    Seevers, P M; Daly, J M; Catedral, F F

    1971-09-01

    In common with other disease situations, rust-resistant wheat leaves show a large increase in peroxidase activity during infection. Peroxidase isozymes from healthy or infected lines of wheat (Triticum aestivum L.) near isogenic for resistance and susceptibility to race 56 of Puccinia graminis tritici were separated by gel electrophoresis and the activity of each was estimated by photometric scanning. In order to ensure that the activity of isozymes observed on gels reflected the changes found in peroxidase enzymes assayed spectrophotometrically in extracts, a study was made of extraction procedures, substrates, and reaction conditions for both types of enzyme measurements. Of the 14 isozymes detected in both healthy and infected leaves, increases in only 1 (isozyme 9) were associated consistently with the development of resistant disease reaction at 20 C. Additional evidence was obtained to show that this isozyme can account for the increased peroxidase activity observed in extracts from resistant plants. When plants with high induced peroxidase activity due to resistance at 20 C were treated with ethylene or transferred to 25 C, they reverted to complete susceptibility. However, the disease-induced activity of isozyme 9 did not fall. The data suggest that, in this case, the association of peroxidase with resistance was a consequence of, not a determinant in, resistance.

  13. Native root-associated bacteria rescue a plant from a sudden-wilt disease that emerged during continuous cropping.

    Science.gov (United States)

    Santhanam, Rakesh; Luu, Van Thi; Weinhold, Arne; Goldberg, Jay; Oh, Youngjoo; Baldwin, Ian T

    2015-09-01

    Plants maintain microbial associations whose functions remain largely unknown. For the past 15 y, we have planted the annual postfire tobacco Nicotiana attenuata into an experimental field plot in the plant's native habitat, and for the last 8 y the number of plants dying from a sudden wilt disease has increased, leading to crop failure. Inadvertently we had recapitulated the common agricultural dilemma of pathogen buildup associated with continuous cropping for this native plant. Plants suffered sudden tissue collapse and black roots, symptoms similar to a Fusarium-Alternaria disease complex, recently characterized in a nearby native population and developed into an in vitro pathosystem for N. attenuata. With this in vitro disease system, different protection strategies (fungicide and inoculations with native root-associated bacterial and fungal isolates), together with a biochar soil amendment, were tested further in the field. A field trial with more than 900 plants in two field plots revealed that inoculation with a mixture of native bacterial isolates significantly reduced disease incidence and mortality in the infected field plot without influencing growth, herbivore resistance, or 32 defense and signaling metabolites known to mediate resistance against native herbivores. Tests in a subsequent year revealed that a core consortium of five bacteria was essential for disease reduction. This consortium, but not individual members of the root-associated bacteria community which this plant normally recruits during germination from native seed banks, provides enduring resistance against fungal diseases, demonstrating that native plants develop opportunistic mutualisms with prokaryotes that solve context-dependent ecological problems.

  14. Can Plant Microbiome Studies Lead to Effective Biocontrol of Plant Diseases?

    Science.gov (United States)

    Ellis, Jeffrey G

    2017-03-01

    In this review, the wisdom and efficacy of studies seeking disease attenuating microbes and microbiomes only in healthy plant communities is questioned and an alternative view is posited, namely that success in biocontrol of crop diseases may also come from studies of microbiota, or at least individual species isolates, associated with diseased plants. In support of this view, I summarize the current extensive knowledge of the biology behind what is probably the most successful biocontrol of a plant disease, namely the biocontrol of crown gall of stone fruit using non-pathogenic Rhizobium rhizogenes K84, in which the biocontrol agent itself came from a diseased plant.

  15. [Construction of plant expression vectors harboring a peptide antibiotic-apidaecin gene and resistance analysis of the transgenic tobacco].

    Science.gov (United States)

    Wang, H; Sun, C; Peng, X X

    2001-07-01

    Two plant expression vectors(pBinPRHbI and pBinPRSIHbI) were constructed: Firstly, apidaecin gene were fused to the signal peptide coding sequencing of a PR-protein, and cloned into a binary vector pBin438 to form pBinPRHbI. Then, the cassette consisting of 35S promoter, PR signal peptide coding sequencing and apidaecin gene was cut off from pBinPRHbI and inserted into another plant expression vector pBinPRSI to produce a bivalent plant expression vector pBinPRSIHbI. pBinPRSI was constructed previously in our lab and contained PR signal peptide and Shiva-I fusion gene under control of 35S promoter. The three plant expression vectors were introduced into tobacco by Agrobacterium-mediated transformation. The positive rate of PCR was 95% in all putative transgenic plants. Results from Southern blot indicated that foreign genes were integrated into tobacco genome and RT-PCR analysis proved that the foreign gene was transcribed in transgenic tobacco. The transgenic tobacco showed higher resistance to P. syringae pv tabaci, the causal agent of tobacco wild fire disease, than their original cultivars. From the disease index, the transgenic plants carrying apidaecin and Shiva-I genes had highest resistance among three kinds of transgenic plants, and the plants carrying Shiva-I gene alone had lowest resistance.

  16. Disease-tolerance of transgenic tobacco plants expressing Ah-AMP gene of Amaranthus hypochondriacus

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An antimicrobial peptide gene from Amaranthus hypochondriacus, Ah-AMP, was amplified by PCR and cloned. Sequence analysis results revealed that this gene is 261 bp in length encoding a precursor polypeptide of 87 amino acid residues. Ah-AMP gene was inserted in the binary vector pBin438 to construct a plant expression vector pBinAH916. Leave explants of Nicotiana tabacum var. SR1 were transformed with Agrobacterium tumefaciens LBA4404 harboring the above expression vector. Results from PCR, Southern and Northern blot analyses confirmed that the Ah-AMP gene had been integrated into the tobacco genome and was transcribed at mRNA level. Two bacterial-resistant transgenic plants were selected by inoculating the plants with Pseudomonas solanacearum and statistic analysis of two T1 lines showed that the resistance increased by 2.24 and 1.62 grade and the disease index decreased by 49.6% and 37.3% respectively when compared with the non-transformed control plants SR1. The results from challenging the plants with inoculums of Phytophthora parasitica showed that the symptom development was delayed and disease index was significantly reduced. These results suggest that Ah-AMP gene may be a potentially valuable gene for genetic engineering of plant for disease-resistance.

  17. Transgenic Rice Plants Harboring Genomic DNA from Zizania latifolia Confer Bacterial Blight Resistance

    Institute of Scientific and Technical Information of China (English)

    SHEN Wei-wei; SONG Cheng-li; CHEN Jie; Fu Ya-ping; Wu Jian-li; JIANG Shao-mei

    2011-01-01

    Based on the sequence of a resistance gene analog FZ14 derived from Zizania latifolia (Griseb.),a pair of specific PCR primers FZ14P1/FZ14P2 was designed to isolate candidate disease resistance gene.The pooled-PCR approach was adopted using the primer pair to screen a genomic transformation-competent artificial chromosome (TAC) library derived from Z.latifolia.A positive TAC clone (ZR1) was obtained and confirmed by sequence analysis.The results indicated that ZR1 consisted of conserved motifs similar to P-loop (kinase 1a),kinase 2,kinase 3a and GLPL (Gly-Leu-Pro-Leu),suggesting that it could be a portion of NBS-LRR type of resistance gene.Using Agrobacterium-mediated transformation of Nipponbare mature embryo,a total of 48 independent transgenic T0 plants were obtained.Among them,36 plants were highly resistant to the virulent bacterial blight strain P×O71.The results indicate that ZR1 contains at least one functional bacterial blight resistance gene.

  18. Non-host Plant Resistance against Phytophthora capsici Is Mediated in Part by Members of the I2 R Gene Family in Nicotiana spp.

    Science.gov (United States)

    Vega-Arreguín, Julio C.; Shimada-Beltrán, Harumi; Sevillano-Serrano, Jacobo; Moffett, Peter

    2017-01-01

    The identification of host genes associated with resistance to Phytophthora capsici is crucial to developing strategies of control against this oomycete pathogen. Since there are few sources of resistance to P. capsici in crop plants, non-host plants represent a promising source of resistance genes as well as excellent models to study P. capsici – plant interactions. We have previously shown that non-host resistance to P. capsici in Nicotiana spp. is mediated by the recognition of a specific P. capsici effector protein, PcAvr3a1 in a manner that suggests the involvement of a cognate disease resistance (R) genes. Here, we have used virus-induced gene silencing (VIGS) and transgenic tobacco plants expressing dsRNA in Nicotiana spp. to identify candidate R genes that mediate non-host resistance to P. capsici. Silencing of members of the I2 multigene family in the partially resistant plant N. edwardsonii and in the resistant N. tabacum resulted in compromised resistance to P. capsici. VIGS of two other components required for R gene-mediated resistance, EDS1 and SGT1, also enhanced susceptibility to P. capsici in N. edwardsonii, as well as in the susceptible plants N. benthamiana and N. clevelandii. The silencing of I2 family members in N. tabacum also compromised the recognition of PcAvr3a1. These results indicate that in this case, non-host resistance is mediated by the same components normally associated with race-specific resistance. PMID:28261255

  19. Resistance of determinant tomato varieties to the causal agents of bacterial wilt disease

    Directory of Open Access Journals (Sweden)

    Jana Víchová

    2011-01-01

    Full Text Available Resistance of determinant tomato varieties to pathogens causing bacterial wilt disease – Clavibacter michiganensis subsp. michiganensis (Cmm and Ralstonia solanacearum (Rs – was tested under greenhouse conditions. In tests to Cmm resistance, two inoculation methods were compared (inoculation “to the cut off top” of a plant and inoculation by three punctures into a stalk. The inoculation method “into a stalk” appeared to be most suitable. In both cases of inoculation, the highest level of resistance was found in Minigold variety. The rather high level of resistance was also found in varieties Aneta and Orange. In tests to Rs resistance, the most resistant varieties were Minigold, Aneta and Orange, which are recommended for direct consumption.

  20. Development of transgenic finger millet (Eleusine coracana (L.) Gaertn.) resistant to leaf blast disease

    Indian Academy of Sciences (India)

    S Ignacimuthu; S Antony Ceasar

    2012-03-01

    Finger millet plants conferring resistance to leaf blast disease have been developed by inserting a rice chitinase (chi11) gene through Agrobacterium-mediated transformation. Plasmid pHyg-Chi.11 harbouring the rice chitinase gene under the control of maize ubiquitin promoter was introduced into finger millet using Agrobacterium strain LBA4404 (pSB1). Transformed plants were selected and regenerated on hygromycin-supplemented medium. Transient expression of transgene was confirmed by GUS histochemical staining. The incorporation of rice chitinase gene in R0 and R1 progenies was confirmed by PCR and Southern blot analyses. Expression of chitinase gene in finger millet was confirmed by Western blot analysis with a barley chitinase antibody. A leaf blast assay was also performed by challenging the transgenic plants with spores of Pyricularia grisea. The frequency of transient expression was 16.3% to 19.3%. Stable frequency was 3.5% to 3.9%. Southern blot analysis confirmed the integration of 3.1 kb chitinase gene. Western blot analysis detected the presence of 35 kDa chitinase enzyme. Chitinase activity ranged from 19.4 to 24.8. In segregation analysis, the transgenic R1 lines produced three resistant and one sensitive for hygromycin, confirming the normal Mendelian pattern of transgene segregation. Transgenic plants showed high level of resistance to leaf blast disease compared to control plants. This is the first study reporting the introduction of rice chitinase gene into finger millet for leaf blast resistance.

  1. The Arabidopsis lectin receptor kinase LecRK-I.9 enhances resistance to Phytophthora infestans in Solanaceous plants.

    Science.gov (United States)

    Bouwmeester, Klaas; Han, Miao; Blanco-Portales, Rosario; Song, Wei; Weide, Rob; Guo, Li-Yun; van der Vossen, Edwin A G; Govers, Francine

    2014-01-01

    Late blight caused by the plant pathogenic oomycete Phytophthora infestans is known as one of the most destructive potato diseases. Plant breeders tend to employ NB-LRR-based resistance for introducing genetically controlled late blight resistance in their breeding lines. However, P. infestans is able to rapidly escape this type of resistance, and hence, NB-LRR-based resistance in potato cultivars is often not durable. Previously, we identified a novel type of Phytophthora resistance in Arabidopsis. This resistance is mediated by the cell surface receptor LecRK-I.9, which belongs to the family of L-type lectin receptor kinases. In this study, we report that expression of the Arabidopsis LecRK-I.9 gene in potato and Nicotiana benthamiana results in significantly enhanced late blight resistance. Transcriptional profiling showed strong reduction in salicylic acid (SA)-mediated defence gene expression in LecRK-I.9 transgenic potato lines (TPLs). In contrast, transcripts of two protease inhibitor genes accumulated to extreme high levels, suggesting that LecRK-I.9-mediated late blight resistance is relying on a defence response that includes activation of protease inhibitors. These results demonstrate that the functionality of LecRK-I.9 in Phytophthora resistance is maintained after interfamily transfer to potato and N. benthamiana and suggest that this novel type of LecRK-based resistance can be exploited in breeding strategies to improve durable late blight resistance in Solanaceous crops.

  2. Hyperspectral remote sensing techniques for early detection of plant diseases

    Science.gov (United States)

    Krezhova, Dora; Maneva, Svetla; Zdravev, Tomas

    Hyperspectral remote sensing is an emerging, multidisciplinary field with diverse applications in Earth observation. Nowadays spectral remote sensing techniques allow presymptomatic monitoring of changes in the physiological state of plants with high spectral resolution. Hyperspectral leaf reflectance and chlorophyll fluorescence proved to be highly suitable for identification of growth anomalies of cultural plants that result from the environmental changes and different stress factors. Hyperspectral technologies can find place in many scientific areas, as well as for monitoring of plants status and functioning to help in making timely management decisions. This research aimed to detect a presence of viral infection in young pepper plants (Capsicum annuum L.) caused by Cucumber Mosaic Virus (CMV) by using hyperspectral reflectance and fluorescence data and to assess the effect of some growth regulators on the development of the disease. In Bulgaria CMV is one of the widest spread pathogens, causing the biggest economical losses in crop vegetable production. Leaf spectral reflectance and fluorescence data were collected by a portable fibre-optics spectrometer in the spectral ranges 450÷850 nm and 600-900 nm. Greenhouse experiment with pepper plants of two cultivars, Sivria (sensitive to CMV) and Ostrion (resistant to CMV) were used. The plants were divided into six groups. The first group consisted of healthy (control) plants. At growth stage 4-6 expanded leaf, the second group was inoculated with CMV. The other four groups were treated with growth regulators: Spermine, MEIA (beta-monomethyl ester of itaconic acid), ВТН (benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester) and Phytoxin. On the next day, the pepper plants of these four groups were inoculated with CMV. The viral concentrations in the plants were determined by the serological method DAS-ELISA. Statistical, first derivative and cluster analysis were applied and several vegetation indices were

  3. Transposon tagging of disease resistance genes. Final report, May 1, 1988--April 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Michelmore, R.

    1994-09-01

    The goal of this project was to develop a transposon mutagenesis system for lettuce and to clone and characterize disease resistance genes by transposon tagging. The majority of studies were conducted with the Ac/Ds System. Researchers made and tested several constructs as well as utilized constructions shown to be functional in other plant species. Researchers demonstrated movement of Ac and DS in lettuce; however, they transposed at much lower frequencies in lettuce than in other plant species. Therefore, further manipulation of the system, particularly for flower specific expression of transposase, is required before a routine transposon system is available for lettuce. Populations of lettuce were generated and screened to test for the stability of resistance genes and several spontaneous mutations were isolated. Researchers also identified a resistance gene mutant in plants transformed with a Ds element and chimeric transposase gene. This is currently being characterized in detail.

  4. Chromium Resistant Bacteria: Impact on Plant Growth in Soil Microcosm

    Directory of Open Access Journals (Sweden)

    Sayel Hanane

    2014-07-01

    Full Text Available Three chromium resistant bacterial strains, Pseudomonas fluorescens PF28, Enterobacter amnigenus EA31 and Enterococcus gallinarum S34 isolated from tannery waste contaminated soil were used in this study. All strains could resist a high concentration of K2Cr2O7 that is up to 300 mg/L. The effect of these strains on clover plants (Trifolium campestre in the presence of two chromium salts CrCl3 and K2Cr2O7 was studied in soil microcosm. Application of chromium salts adversely affected seed germination, root and shoot length. Bacterial inoculation improved the growth parameters under chromate stress when compared with non inoculated respective controls. There was observed more than 50% reduction of Cr(VI in inoculated soil microcosms, as compared to the uninoculated soil under the same conditions. The results obtained in this study are significant for the bioremediation of chromate pollution.

  5. Plant adaptogens increase lifespan and stress resistance in C. elegans.

    Science.gov (United States)

    Wiegant, F A C; Surinova, S; Ytsma, E; Langelaar-Makkinje, M; Wikman, G; Post, J A

    2009-02-01

    Extracts of plant adaptogens such as Eleutherococcus senticosus (or Acanthopanax senticosus) and Rhodiola rosea can increase stress resistance in several model systems. We now show that both extracts also increase the mean lifespan of the nematode C. elegans in a dose-dependent way. In at least four independent experiments, 250 microg/ml Eleutherococcus (SHE-3) and 10-25 microg/ml Rhodiola (SHR-5) significantly increased life span between 10 and 20% (P adaptogen extracts were also able to increase stress resistance in C. elegans: against a relatively short heat shock (35 degrees C during 3 h) as well as chronic heat treatment at 26 degrees C. An increase against chronic oxidative stress conditions was observed in mev-1 mutants, and during exposure of the wild type nematode to paraquat (10 mM) or UV stress, be it less efficiently. Concerning the mode of action: both adaptogens induce translocation of the DAF-16 transcription factor from the cytoplasm into the nucleus, suggesting a reprogramming of transcriptional activities favoring the synthesis of proteins involved in stress resistance (such as the chaperone HSP-16) and longevity. Based on these observations, it is suggested that adaptogens are experienced as mild stressors at the lifespan-enhancing concentrations and thereby induce increased stress resistance and a longer lifespan.

  6. Low resistance against novel 2-benzylamino-1,3,5-triazine herbicides in atrazine-resistant Chenopodium album plants

    NARCIS (Netherlands)

    Kohno, H.; Ohki, A.; Koizumi, K.; Noort, van den M.E.; Rodrigues, G.C.; Rensen, van J.J.S.; Wakabayashi, K.

    2000-01-01

    The effects of nine novel 2-benzylamino-1,3,5-triazines on photosynthetic reactions were measured in thylakoids isolated from wild-type and atrazine-resistant plants of Chenopodium album. The resistant plants have a mutation of serine for glycine at position 264 of the D1 protein. The measurement of

  7. Low resistance against novel 2-benzylamino-1,3,5-triazine herbicides in atrazine-resistant Chenopodium album plants

    NARCIS (Netherlands)

    Kohno, H.; Ohki, A.; Koizumi, K.; Noort, van den M.E.; Rodrigues, G.C.; Rensen, van J.J.S.; Wakabayashi, K.

    2000-01-01

    The effects of nine novel 2-benzylamino-1,3,5-triazines on photosynthetic reactions were measured in thylakoids isolated from wild-type and atrazine-resistant plants of Chenopodium album. The resistant plants have a mutation of serine for glycine at position 264 of the D1 protein. The measurement of

  8. Spatial risk assessment of alien plants in China using biodiversity resistance theory

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-06-01

    Full Text Available In the present study, the potential occurrence risk of invasive plants across different provinces of China is studied using disease risk mapping techniques (empirical Bayesian smoothing and Poisson-Gamma model. The biodiversity resistance theory which predicts that high-biodiversity areas will have reduced risk of species invasion serves as the base for performing spatial risk assessment of plant invasion across provinces. The results show that, both risk mapping methods identified that north-eastern part of China have the highest relative risk of plant invasion. In contrast, south-western and south-eastern parts of China, which have high woody plant richness, are predicted to possess low relative risks of plant invasion. Through spatial regression analysis (simultaneous autoregression model, nine environmental variables representing energy availability, water availability, seasonality, and habitat heterogeneity are used to explain the relative risk of plant invasion across provinces of China. The fitting results suggest that, PRECrange and TEMrange are the most two important covariates correlated with the occurrence risks of alien plants at provincial level in China. As indicated by Moran's I index, spatial regression analysis can effectively eliminate the potential biases caused by spatial autocorrelation.

  9. Disease Resistance in Maize and the Role of Molecular Breeding in Defending Against Global Threat

    Institute of Scientific and Technical Information of China (English)

    Farhan Ali; Jianbing Yan

    2012-01-01

    Diseases are a potential threat to global food security but plants have evolved an extensive array of methodologies to cope with the invading pathogens.Non-host resistance and quantitative resistance are broad spectrum forms of resistance,and all kinds of resistances are controlled by extremely diverse genes called “R-genes”.R-genes follow different mechanisms to defend plants and PAMP-induced defenses in susceptible host plants are referred to as basal resistance.Genetic and phenotypic diversity are vital in maize (Zea mays L.); as such,genome wide association study (GWAS)along with certain other methodologies can explore the maximum means of genetic diversity.Exploring the complete genetic architecture to manipulate maize genetically reduces the losses from hazardous diseases.Genomic studies can reveal the interaction between different genes and their pathways.By confirming the specific role of these genes and protein-protein interaction (proteomics) via advanced molecular and bioinformatics tools,we can shed a light on the most complicated and abstruse phenomena of resistance.

  10. Identification of candidate genome regions controlling disease resistance in Arachis

    Directory of Open Access Journals (Sweden)

    Pike Jodie

    2009-08-01

    Full Text Available Abstract Background Worldwide, diseases are important reducers of peanut (Arachis hypogaea yield. Sources of resistance against many diseases are available in cultivated peanut genotypes, although often not in farmer preferred varieties. Wild species generally harbor greater levels of resistance and even apparent immunity, although the linkage of agronomically un-adapted wild alleles with wild disease resistance genes is inevitable. Marker-assisted selection has the potential to facilitate the combination of both cultivated and wild resistance loci with agronomically adapted alleles. However, in peanut there is an almost complete lack of knowledge of the regions of the Arachis genome that control disease resistance. Results In this work we identified candidate genome regions that control disease resistance. For this we placed candidate disease resistance genes and QTLs against late leaf spot disease on the genetic map of the A-genome of Arachis, which is based on microsatellite markers and legume anchor markers. These marker types are transferable within the genus Arachis and to other legumes respectively, enabling this map to be aligned to other Arachis maps and to maps of other legume crops including those with sequenced genomes. In total, 34 sequence-confirmed candidate disease resistance genes and five QTLs were mapped. Conclusion Candidate genes and QTLs were distributed on all linkage groups except for the smallest, but the distribution was not even. Groupings of candidate genes and QTLs for late leaf spot resistance were apparent on the upper region of linkage group 4 and the lower region of linkage group 2, indicating that these regions are likely to control disease resistance.

  11. Genetic analysis of resistance gene analogues from a sugarcane cultivar resistant to red rot disease

    Science.gov (United States)

    One of the important approaches for disease control in sugarcane is to develop a disease resistant variety; this may be accomplished through identification of resistance genes in sugarcane. In this study, PCR primers targeting the conserved motifs of the nucleotide-binding site (NBS) class and kinas...

  12. Competitive Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-Spectrum Late Blight Resistance

    Science.gov (United States)

    Potato late blight is a particularly destructive plant disease caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary. Late blight has remained particularly problematic despite intensive breeding efforts to integrate resistance into cultivated potato. This is due to the pathogen’s ab...

  13. Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.

    Science.gov (United States)

    Mougabure-Cueto, Gastón; Picollo, María Inés

    2015-09-01

    Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid

  14. Study on the Resistance Indexes of Four Kinds of Desert Plants in Qinghai Lake Area

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The research aimed to study the resistance of four kinds of desert plants in Qinhai Lake area.[Method] By contrasting the resistance indexes of four kinds of plants which included Ephedra intermedia,Stellera chamaejasme,Achnatherum splendens and Xanthopappus subacaulis,the resistance of four kinds of plants in Qinghai Lake area was analyzed.The resistance indexes included the soluble protein,MDA,free Pro content and the activities of SOD,POD,CAT.Moreover,the resistance of four kinds of plants wa...

  15. The Arabidopsis NPR1 gene confers broad-spectrum disease resistance in strawberry.

    Science.gov (United States)

    Silva, Katchen Julliany P; Brunings, Asha; Peres, Natalia A; Mou, Zhonglin; Folta, Kevin M

    2015-08-01

    Although strawberry is an economically important fruit crop worldwide, production of strawberry is limited by its susceptibility to a wide range of pathogens and the lack of major commercial cultivars with high levels of resistance to multiple pathogens. The objective of this study is to ectopically express the Arabidopsis thaliana NPR1 gene (AtNPR1) in the diploid strawberry Fragaria vesca L. and to test transgenic plants for disease resistance. AtNPR1 is a key positive regulator of the long-lasting broad-spectrum resistance known as systemic acquired resistance (SAR) and has been shown to confer resistance to a number of pathogens when overexpressed in Arabidopsis or ectopically expressed in several crop species. We show that ectopic expression of AtNPR1 in strawberry increases resistance to anthracnose, powdery mildew, and angular leaf spot, which are caused by different fungal or bacterial pathogens. The increased resistance is related to the relative expression levels of AtNPR1 in the transgenic plants. In contrast to Arabidopsis plants overexpressing AtNPR1, which grow normally and do not constitutively express defense genes, the strawberry transgenic plants are shorter than non-transformed controls, and most of them fail to produce runners and fruits. Consistently, most of the transgenic lines constitutively express the defense gene FvPR5, suggesting that the SAR activation mechanisms in strawberry and Arabidopsis are different. Nevertheless, our results indicate that overexpression of AtNPR1 holds the potential for generation of broad-spectrum disease resistance in strawberry.

  16. Reevaluating the conceptual framework for applied research on host-plant resistance

    Institute of Scientific and Technical Information of China (English)

    Michael J.Stout

    2013-01-01

    Applied research on host-plant resistance to arthropod pests has been guided over the past 60 years by a framework originally developed by Reginald Painter in his 1951 book,Insect Resistance in Crop Plants.Painter divided the "phenomena" of resistance into three "mechanisms," nonpreference (later renamed antixenosis),antibiosis,and tolerance.The weaknesses of this framework are discussed.In particular,this trichotomous framework does not encompass all known mechanisms of resistance,and the antixenosis and antibiosis categories are ambiguous and inseparable in practice.These features have perhaps led to a simplistic approach to understanding arthropod resistance in crop plants.A dichotomous scheme is proposed as a replacement,with a major division between resistance (plant traits that limit injury to the plant) and tolerance (plant traits that reduce amount of yield loss per unit injury),and the resistance category subdivided into constitutive/inducible and direct/indirect subcategories.The most important benefits of adopting this dichotomous scheme are to more closely align the basic and applied literatures on plant resistance and to encourage a more mechanistic approach to studying plant resistance in crop plants.A more mechanistic approach will be needed to develop novel approaches for integrating plant resistance into pest management programs.

  17. Plant Disease Control by the Use of Chemicals. MP-27.

    Science.gov (United States)

    Ross, William D.; Bridgmon, George H.

    This document has been prepared as a reference manual providing information regarding plant diseases. The text concerns itself with the identification and development of infectious and non-infectious diseases and associated control measures. An appendix includes a glossary of plant pathological terms and a bibliography. (CS)

  18. New martensitic steels for fossil power plant: Creep resistance

    Science.gov (United States)

    Kaybyshev, R. O.; Skorobogatykh, V. N.; Shchenkova, I. A.

    2010-02-01

    In this paper, we consider the origin of high-temperature strength of heat-resistant steels belonging to martensitic class developed on the basis of the Fe—9%Cr alloy for the boiler pipes and steam pipelines of power plants at steam temperatures of up to 620°C and pressures to 300 atm. In addition, we give a brief information on the physical processes that determine the creep strength and consider the alloying philosophy of traditional heat-resistant steels. The effect of the chemical and phase composition of heat-resistant steels and their structure on creep strength is analyzed in detail. It is shown that the combination of the solid-solution alloying by elements such as W and Mo, as well as the introduction of carbides of the MX type into the matrix with the formation of a dislocation structure of tempered martensite, ensures a significant increase in creep resistance. The steels of the martensitic class withstand creep until an extensive polygonization starts in the dislocation structure of the tempered martensite(“troostomartensite”), which is suppressed by V(C,N) and Nb(C,N) dispersoids. Correspondingly, the service life of these steels is determined by the time during which the dispersed nanocarbonitrides withstand coalescence, while tungsten and molybdenum remain in the solid solution. The precipitation of the Laves phases Fe2(W,Mo) and the coalescence of carbides lead to the development of migration of low-angle boundaries, and the steel loses its ability to resist creep.

  19. Can vessel dimension explain tolerance toward fungal vascular wilt diseases in woody plants? Lessons from Dutch elm disease and esca disease in grapevine

    OpenAIRE

    Jerome ePouzoulet; Alexandria ePivovaroff; Louis eSantiago; Philippe Eric Rolshausen

    2014-01-01

    This review illuminates key findings in our understanding of grapevine xylem resistance to fungal vascular wilt diseases. Grapevine (Vitis spp.) vascular diseases such as esca, botryosphaeria dieback, and eutypa dieback, are caused by a set of taxonomically unrelated ascomycete fungi. Fungal colonization of the vascular system leads to a decline of the plant host because of a loss of the xylem function and subsequent decrease in hydraulic conductivity. Fungal vascular pathogens use different ...

  20. Multitrophic effects of plant resistance: from basic ecology to application in transgenic crops

    NARCIS (Netherlands)

    Kos, M.

    2012-01-01

    Plants have evolved a wide array of direct and indirect resistance traits that prevent or reduce herbivory by insects. The aim of this thesis was to study the effects of direct and indirect plant resistance traits on the multitrophic interactions between brassicaceous plants, leaf-chewing and phloem

  1. HOPM1 mediated disease resistance to Pseudomonas syringae in Arabidopsis

    Science.gov (United States)

    He, Sheng Yang [Okemos, MI; Nomura, Kinya [East Lansing, MI

    2011-11-15

    The present invention relates to compositions and methods for enhancing plant defenses against pathogens. More particularly, the invention relates to enhancing plant immunity against bacterial pathogens, wherein HopM1.sub.1-300 mediated protection is enhanced, such as increased protection to Pseudomonas syringae pv. tomato DC3000 HopM1 and/or there is an increase in activity of an ATMIN associated plant protection protein, such as ATMIN7. Reagents of the present invention further provide a means of studying cellular trafficking while formulations of the present inventions provide increased pathogen resistance in plants.

  2. Problems, challenges and future of plant disease management:from an ecological point of view

    Institute of Scientific and Technical Information of China (English)

    HE Dun-chun; ZHAN Jia-sui; XIE Lian-hui

    2016-01-01

    Plant disease management faces ever-growing chalenges due to: (i) increasing demands for total, safe and diverse foods to support the booming global population and its improving living standards; (i) reducing production potential in agriculture due to competition for land in fertile areas and exhaustion of marginal arable lands; (ii) deteriorating ecology of agro-ecosystems and depletion of natural resources; and (iv) increased risk of disease epidemics resulting from agricultural intensiifcation and monocultures. Future plant disease management should aim to strengthen food security for a stable society while simultaneously safeguarding the health of associated ecosystems and reducing dependency on natural resources. To achieve these multiple functionalities, sustainable plant disease management should place emphases on rational adaptation of resistance, avoidance, elimination and remediation strategies individualy and colectively, guided by traits of speciifc host-pathogen associations using evolutionary ecology principles to create environmental (biotic and abiotic) conditions favorable for host growth and development while adverse to pathogen reproduction and evolution.

  3. Plant Diseases and Management Approaches in Organic Farming Systems.

    Science.gov (United States)

    van Bruggen, A H C; Finckh, M R

    2016-08-04

    Organic agriculture has expanded worldwide. Numerous papers were published in the past 20 years comparing plant diseases in organic and conventional crops. Root diseases are generally less severe owing to greater soil health, whereas some foliar diseases can be problematic in organic agriculture. The soil microbial community and nitrogen availability play an important role in disease development and yield. Recently, the focus has shifted to optimizing organic crop production by improving plant nutrition, weed control, and plant health. Crop-loss assessment relating productivity to all yield-forming and -reducing factors would benefit organic production and sustainability evaluation.

  4. Growth of Verticillium longisporum in Xylem Sap of Brassica napus is Independent from Cultivar Resistance but Promoted by Plant Aging.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-09-01

    As Verticillium stem striping of oilseed rape (OSR), a vascular disease caused by Verticillium longisporum, is extending into new geographic regions and no control with fungicides exists, the demand for understanding mechanisms of quantitative resistance increases. Because V. longisporum is strictly limited to the xylem and resistance is expressed in the systemic stage post root invasion, we investigated a potential antifungal role of soluble constituents and nutritional conditions in xylem sap as determinants of cultivar resistance of OSR to V. longisporum. Assessment of biometric and molecular genetic parameters applied to describe V. longisporum resistance (net area under disease progress curve, stunting, stem thickness, plant biomass, and V. longisporum DNA content) showed consistent susceptibility of cultivar 'Falcon' in contrast to two resistant genotypes, 'SEM' and 'Aviso'. Spectrophotometric analysis revealed a consistently stronger in vitro growth of V. longisporum in xylem sap extracted from OSR compared with the water control. Further comparisons of fungal growth in xylem sap of different cultivars revealed the absence of constitutive or V. longisporum induced antifungal activity in the xylem sap of resistant versus susceptible genotypes. The similar growth of V. longisporum in xylem sap, irrespective of cultivar, infection with V. longisporum and xylem sap filtration, was correlated with about equal amounts of total soluble proteins in xylem sap from these treatments. Interestingly, compared with younger plants, xylem sap from older plants induced significantly stronger fungal growth. Growth enhancement of V. longisporum in xylem sap of aging plants was reflected by increased contents of carbohydrates, which was consistent in mock or V. longisporum-infected plants and independent from cultivar resistance. The improved nutritional conditions in the xylem of more mature plants may explain the late appearance of disease symptoms, which are observed only in

  5. Transgenic strategies for improving rice disease resistance

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-04

    May 4, 2009 ... This RTSV Rep-mediated resistance was effective against geographically ..... ethylene (ET)/jasmonic acid (JA)-mediated signaling pathways, which are ... allene oxide synthase, a key enzyme in the JA biosyn- thetic pathway ...

  6. Molecular genetics and evolution of disease resistance in cereals.

    Science.gov (United States)

    Krattinger, Simon G; Keller, Beat

    2016-10-01

    Contents 320 I. 320 II. 321 III. 321 IV. 322 V. 324 VI. 328 VII. 329 330 References 330 SUMMARY: Cereal crops produce a large part of the globally consumed food and feed. Because of the constant presence of devastating pathogens, the molecular characterization of disease resistance is a major research area and highly relevant for breeding. There has been recent and accelerating progress in the understanding of three distinct resistance mechanisms in cereals: resistance conferred by plasma membrane-localized receptor proteins; race-specific resistance conferred by intracellular immune receptors; and quantitative disease resistance. Intracellular immune receptors provide a particularly rich source for evolutionary studies, and have, for example, resulted in the recent discovery of a novel detection mechanism based on integrated decoy domains. Evolutionary studies have also revealed the origins of active resistance genes in both wild progenitors of today's cereals as well as in cultivated forms. In addition, independent evolution of orthologous genes in related cereals has resulted in resistance to different pathogen species. Quantitative resistance genes have been best characterized in wheat. The quantitative resistance genes identified so far in wheat encode transporter proteins or unusual kinase proteins. The recent discoveries in these three different resistance mechanisms have contributed to the basic molecular understanding of cereal immunity against pathogens and have suggested novel applications for resistance breeding.

  7. Copper-resistant bacteria enhance plant growth and copper phytoextraction.

    Science.gov (United States)

    Yang, Renxiu; Luo, Chunling; Chen, Yahua; Wang, Guiping; Xu, Yue; Shen, Zhenguo

    2013-01-01

    In this study, we investigated the role of rhizospheric bacteria in solubilizing soil copper (Cu) and promoting plant growth. The Cu-resistant bacterium DGS6 was isolated from a natural Cu-contaminated soil and was identified as Pseudomonas sp. DGS6. This isolate solubilized Cu in Cu-contaminated soil and stimulated root elongation of maize and sunflower. Maize was more sensitive to inoculation with DGS6 than was sunflower and exhibited greater root elongation. In pot experiment, inoculation with DGS6 increased the shoot dry weight of maize by 49% and sunflower by 34%, and increased the root dry weight of maize by 85% and sunflower by 45%. Although the concentrations of Cu in inoculated and non-inoculated seedlings did not differ significantly, the total accumulation of Cu in the plants increased after inoculation. DGS6 showed a high ability to solubilize P and produce iron-chelating siderophores, as well as significantly improved the accumulation of P and Fe in both maize and sunflower shoots. In addition, DGS6 produced indole-3-acetic acid (IAA) and ACC deaminase, which suggests that it may modulate ethylene levels in plants. The bacterial strain DGS6 could be a good candidate for re-vegetation of Cu-contaminated sites. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.

  8. Molecular mechanisms of insulin resistance and associated diseases.

    Science.gov (United States)

    Mlinar, Barbara; Marc, Janja; Janez, Andrej; Pfeifer, Marija

    2007-01-01

    Insulin resistance is a state in which higher than normal concentrations of insulin are required for normal response. The most common underlying cause is central obesity, although primary insulin resistance in normal-weight individuals is also possible. Excess abdominal adipose tissue has been shown to release increased amounts of free fatty acids which directly affect insulin signalling, diminish glucose uptake in muscle, drive exaggerated triglyceride synthesis and induce gluconeogenesis in the liver. Other factors presumed to play the role in insulin resistance are tumour necrosis factor alpha, adiponectin, leptin, IL-6 and some other adipokines. Hyperinsulinaemia which accompanies insulin resistance may be implicated in the development of many pathological states, such as hypertension and hyperandrogenaemia. Insulin resistance underlies metabolic syndrome and is further associated with polycystic ovary syndrome and lipodystrophies. When beta-cells fail to secrete the excess insulin needed, diabetes mellitus type 2 emerges, which is, besides coronary heart disease, the main complication of insulin resistance and associated diseases.

  9. Enhancing disease resistances of Super Hybrid Rice with four antifungal genes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A plant expression vector harboring four antifungal genes was delivered into the embryogenic calli of ‘9311’, an indica restorer line of Super Hybrid Rice, via modified biolistic particle bombardment. Southern blot analysis indicated that in the regenerated hygromycin-resistant plants, all the four anti-fungal genes, including RCH10, RAC22, β-Glu and B-RIP, were integrated into the genome of ‘9311’, co-transmitted altogether with the marker gene hpt in a Mendelian pattern. Some transgenic R1 and R2 progenies, with all transgenes displaying a normal expression level in the Northern blot analysis, showed high resistance to Magnaporthe grisea when tested in the typical blast nurseries located in Yanxi and Sanya respectively. Furthermore, transgenic F1 plants, resulting from a cross of R2 homo-zygous lines with high resistance to rice blast with the non-transgenic male sterile line Peiai 64S, showed not only high resistance to M. grisea but also enhanced resistance to rice false smut (a disease caused by Ustilaginoidea virens) and rice kernel smut (another disease caused by Tilletia barclayana).

  10. Therapeutic efficacy of the neuroprotective plant adaptogen in neurodegenerative disease (Parkinson's disease as an example).

    Science.gov (United States)

    Bocharov, E V; Ivanova-Smolenskaya, I A; Poleshchuk, V V; Kucheryanu, V G; Il'enko, V A; Bocharova, O A

    2010-11-01

    Therapeutic efficacy of the plant neuroprotector Phytomix-40 in Parkinson's disease was demonstrated. This preparation consists of the components from extracts of 40 plants, including some adaptogens (ginseng, eleutherococcus, Rhodiola rosea, etc.). The preparation normalized immune, antioxidant, and hormonal parameters in patients. The neuroprotective plant adaptogen can be used in complex therapy for Parkinson's disease for improving its efficacy.

  11. Determinants of Pseudomonas putida WCS358 involved in inducing systemic resistance in plants.

    Science.gov (United States)

    Meziane, Hamid; VAN DER Sluis, Ientse; VAN Loon, Leendert C; Höfte, Monica; Bakker, Peter A H M

    2005-03-01

    SUMMARY Pseudomonas putida WCS358 is a plant growth-promoting rhizobacterium originally isolated from the rhizosphere of potato. It can suppress soil-borne plant diseases by siderophore-mediated competition for iron, but it has also been reported to result in induced systemic resistance (ISR) in Arabidopsis thaliana. Bacterial determinants of this strain involved in inducing systemic resistance in Arabidopsis were investigated using a Tn5 transposon mutant defective in biosynthesis of the fluorescent siderophore pseudobactin, a non-motile Tn5 mutant lacking flagella, and a spontaneous phage-resistant mutant lacking the O-antigenic side chain of the lipopolysaccharides (LPS). When using Pseudomonas syringae pv. tomato as the challenging pathogen, purified pseudobactin, flagella and LPS all triggered ISR. However, the mutants were all as effective as the parental strain, suggesting redundancy in ISR-triggering traits in WCS358. The Botrytis cinerea-tomato, B. cinerea-bean and Colletotrichum lindemuthianum-bean model systems were used to test further the potential of P. putida WCS358 to induce ISR. Strain WCS358 significantly reduced disease development in all three systems, indicating that also on tomato and bean WCS358 can trigger ISR. In both tomato and bean, the LPS mutant had lost the ability to induce resistance, whereas the flagella mutant was still effective. In bean, the pseudobactin mutant was still effective, whereas this mutant has lost its effectivity in tomato. In both bean and tomato, flagella isolated from the parental strain were not effective, whereas LPS or pseudobactin did induce systemic resistance.

  12. Metal hyperaccumulation armors plants against disease

    National Research Council Canada - National Science Library

    Fones, Helen; Davis, Calum A R; Rico, Arantza; Fang, Fang; Smith, J Andrew C; Preston, Gail M

    2010-01-01

    Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate...

  13. Antibiotic Resistant Bacteria And Their Associated Resistance Genes in a Conventional Municipal Wastewater Treatment Plant

    KAUST Repository

    Aljassim, Nada I.

    2013-12-01

    With water scarcity as a pressing issue in Saudi Arabia and other Middle Eastern countries, the treatment and reuse of municipal wastewater is increasingly being used as an alternative water source to supplement country water needs. Standards are in place to ensure a safe treated wastewater quality, however they do not regulate pathogenic bacteria and emerging contaminants. Information is lacking on the levels of risk to public health associated with these factors, the efficiency of conventional treatment strategies in removing them, and on wastewater treatment in Saudi Arabia in general. In this study, a municipal wastewater treatment plant in Saudi Arabia is investigated to assess the efficiency of conventional treatment in meeting regulations and removing pathogens and emerging contaminants. The study found pathogenic bacterial genera, antibiotic resistance genes and antibiotic resistant bacteria, many of which were multi-resistant in plant discharges. It was found that although the treatments are able to meet traditional quality guidelines, there remains a risk from the discussed contaminants with wastewater reuse. A deeper understanding of this risk, and suggestions for more thorough guidelines and monitoring are needed.

  14. Drought tolerance in Arabidopsis is controlled by the OCP3 disease resistance regulator.

    Science.gov (United States)

    Ramírez, Vicente; Coego, Alberto; López, Ana; Agorio, Astrid; Flors, Víctor; Vera, Pablo

    2009-05-01

    Water scarcity and corresponding abiotic drought stress is one of the most important factors limiting plant performance and yield. In addition, plant productivity is severely compromised worldwide by infection with microbial pathogens. Two of the most prominent pathways responsible for drought tolerance and disease resistance to fungal pathogens in Arabidopsis are those controlled by the phytohormones abscisic acid (ABA) and the oxylipin methyl jasmonate (MeJA), respectively. Here, we report on the functional characterization of OCP3, a transcriptional regulator from the homeodomain (HD) family. The Arabidopsis loss-of-function ocp3 mutant exhibits both drought resistance and enhanced disease resistance to necrotrophic fungal pathogens. Double-mutant analysis revealed that these two resistance phenotypes have different genetic requirements. Whereas drought tolerance in ocp3 is ABA-dependent but MeJA-independent, the opposite holds true for the enhanced disease resistance characteristics. These observations lead us to propose a regulatory role of OCP3 in the adaptive responses to these two stresses, functioning as a modulator of independent and specific aspects of the ABA- and MeJA-mediated signal transduction pathways.

  15. Ultrastructures of Colletotrichum orbiculare in the Leaves of Cucumber Plants Expressing Induced Systemic Resistance Mediated by Glomus intraradices BEG110.

    Science.gov (United States)

    Jeun, Yong Chull; Lee, Yun Jung; Kim, Ki Woo; Kim, Su Jung; Lee, Sang Woo

    2008-12-01

    The colonization of an arbuscular mycorrhizal fungus Glomus intraradices BEG110 in the soil caused a decrease in disease severity in cucumber plants after fungal inoculation with Colletotrichum orbiculare. In order to illustrate the resistance mechanism mediated by G. intraradices BEG110, infection patterns caused by C. orbiculare in the leaves of cucumber plants and the host cellular responses were characterized. These properties were characterized using transmission electron microscopy on the leaves of cucumber plants grown in soil colonized with G. intraradices BEG110. In the untreated plants, inter- and intra-cellular fungal hyphae were observed throughout the leaf tissues during both the biotrophic and necrotrophic phases of infection. The cytoplasm of fungal hyphae appeared intact during the biotrophic phase, suggesting no defense response against the fungus. However, several typical resistance responses were observed in the plants when treated with G. intraradices BEG110 including the formation of sheaths around the intracellular hyphae or a thickening of host cell walls. These observations suggest that the resistance mediated by G. intraradices BEG110 most often occurs in the symplast of the host cells rather than in the apoplast. In addition, this resistance is similar to those mediated by biotic inducers such as plant growth promoting rhizobacteria.

  16. Plant Polyphenols as Dietary Antioxidants in Human Health and Disease

    Directory of Open Access Journals (Sweden)

    Kanti Bhooshan Pandey

    2009-01-01

    Full Text Available Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. In the last decade, there has been much interest in the potential health benefits of dietary plant polyphenols as antioxidant. Epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis and neurodegenerative diseases. Here we present knowledge about the biological effects of plant polyphenols in the context of relevance to human health.

  17. In silico identification of coffee genome expressed sequences potentially associated with resistance to diseases

    Science.gov (United States)

    2010-01-01

    Sequences potentially associated with coffee resistance to diseases were identified by in silico analyses using the database of the Brazilian Coffee Genome Project (BCGP). Keywords corresponding to plant resistance mechanisms to pathogens identified in the literature were used as baits for data mining. Expressed sequence tags (ESTs) related to each of these keywords were identified with tools available in the BCGP bioinformatics platform. A total of 11,300 ESTs were mined. These ESTs were clustered and formed 979 EST-contigs with similarities to chitinases, kinases, cytochrome P450 and nucleotide binding site-leucine rich repeat (NBS-LRR) proteins, as well as with proteins related to disease resistance, pathogenesis, hypersensitivity response (HR) and plant defense responses to diseases. The 140 EST-contigs identified through the keyword NBS-LRR were classified according to function. This classification allowed association of the predicted products of EST-contigs with biological processes, including host defense and apoptosis, and with molecular functions such as nucleotide binding and signal transducer activity. Fisher's exact test was used to examine the significance of differences in contig expression between libraries representing the responses to biotic stress challenges and other libraries from the BCGP. This analysis revealed seven contigs highly similar to catalase, chitinase, protein with a BURP domain and unknown proteins. The involvement of these coffee proteins in plant responses to disease is discussed. PMID:21637594

  18. Natural selection on plant resistance to herbivores in the native and introduced range

    OpenAIRE

    2015-01-01

    When plants are introduced into new regions, the absence of their co-evolved natural enemies can result in lower levels of attack. As a consequence of this reduction in enemy pressure, plant performance may increase and selection for resistance to enemies may decrease. In the present study, we compared leaf damage, plant size and leaf trichome density, as well as the direction and magnitude of selection on resistance and plant size between non-native (Spain) and native (Mexico) populations of...

  19. Transgenic resistance confers effective field level control of bacterial spot disease in tomato.

    Directory of Open Access Journals (Sweden)

    Diana M Horvath

    Full Text Available We investigated whether lines of transgenic tomato (Solanum lycopersicum expressing the Bs2 resistance gene from pepper, a close relative of tomato, demonstrate improved resistance to bacterial spot disease caused by Xanthomonas species in replicated multi-year field trials under commercial type growing conditions. We report that the presence of the Bs2 gene in the highly susceptible VF 36 background reduced disease to extremely low levels, and VF 36-Bs2 plants displayed the lowest disease severity amongst all tomato varieties tested, including commercial and breeding lines with host resistance. Yields of marketable fruit from transgenic lines were typically 2.5 times that of the non-transformed parent line, but varied between 1.5 and 11.5 fold depending on weather conditions and disease pressure. Trials were conducted without application of any copper-based bactericides, presently in wide use despite negative impacts on the environment. This is the first demonstration of effective field resistance in a transgenic genotype based on a plant R gene and provides an opportunity for control of a devastating pathogen while eliminating ineffective copper pesticides.

  20. Measurement of insulin resistance in chronic kidney disease.

    Science.gov (United States)

    Pham, Hien; Utzschneider, Kristina M; de Boer, Ian H

    2011-11-01

    Insulin resistance is a known complication of end-stage renal disease that also appears to be present in earlier stages of chronic kidney disease (CKD). It is a risk factor for cardiovascular disease and an important potential therapeutic target in this population. Measurement of insulin resistance is reviewed in the context of known pathophysiologic abnormalities in CKD. Insulin resistance in CKD is due to a high prevalence of known risk factors (e.g. obesity) and to unique metabolic abnormalities. The site of insulin resistance in CKD is localized to skeletal muscle. Estimates based on fasting insulin concentration may not adequately capture insulin resistance in CKD because they largely reflect hepatic defects and because CKD impairs insulin catabolism. A variety of dynamic tests are available to directly measure insulin-mediated glucose uptake. Insulin resistance may be an important therapeutic target in CKD. Complementary methods are available to assess insulin resistance, and each method has unique advantages, disadvantages, and levels of complexity. These characteristics, and the likelihood that CKD alters the performance of some insulin resistance measurements, must be considered when designing and interpreting clinical studies.

  1. Breeding for disease resistance in cacao

    Science.gov (United States)

    Cacao production must increase in order to meet the projected rise in the demand for chocolate. Approximately one-third of global production is lost annually to diseases and insects. Four diseases account for the greatest losses worldwide: black pod, caused by four Phytophthora spp; witches’ broom...

  2. Insulin resistance: The linchpin between prediabetes and cardiovascular disease.

    Science.gov (United States)

    Salazar, Martin R; Carbajal, Horacio A; Espeche, Walter G; Aizpurúa, Marcelo; Leiva Sisnieguez, Carlos E; Leiva Sisnieguez, Betty C; Stavile, Rodolfo N; March, Carlos E; Reaven, Gerald M

    2016-03-01

    The aim of this study was to test the hypothesis that cardiovascular disease occurs to the greatest extent in persons with prediabetes mellitus who are also insulin resistant. In 2003, 664 non-diabetic women (n = 457) and men (n = 207), aged 52 ± 16 and 53 ± 15 years, were surveyed during a programme for cardiovascular disease prevention. Fasting plasma glucose concentrations defined participants as having normal fasting plasma glucose (fasting plasma glucose cardiovascular disease risk factors were accentuated in prediabetes mellitus versus normal fasting glucose, particularly in prediabetes mellitus/insulin resistant. In 2012, 86% of the sample were surveyed again, and the crude incidence for cardiovascular disease was higher in subjects with prediabetes mellitus versus normal fasting glucose (13.7 vs 6.0/100 persons/10 years; age- and sex-adjusted hazard ratio = 1.88, p = 0.052). In prediabetes mellitus, the crude incidences were 22.9 versus 9.6/100 persons/10 years in insulin resistant versus non-insulin resistant persons (age- and sex-adjusted hazard ratio = 2.36, p = 0.040). In conclusion, cardiovascular disease risk was accentuated in prediabetes mellitus/insulin resistant individuals, with a relative risk approximately twice as high compared to prediabetes mellitus/non-insulin resistant subjects.

  3. Identification of genes contributing to quantitative disease resistance in rice

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Despite the importance of quantitative disease resistance during a plant’s life, little is known about the molecular basis of this type of host-pathogen interaction, because most of the genes underlying resistance quantitative trait loci (QTLs) are unknown. To identify genes contributing to resistance QTLs in rice, we analyzed the colocalization of a set of characterized rice defense-responsive genes and resistance QTLs against different pathogens. We also examined the expression patterns of these genes in response to pathogen infection in the parents of the mapping populations, based on the strategy of validation and functional analysis of the QTLs. The results suggest that defense-responsive genes are important resources of resistance QTLs in rice. OsWRKY45-1 is the gene contributing to a major resistance QTL.NRR,OsGH3-1,and OsGLP members on chromosome 8 contribute alone or collectively to different minor resistance QTLs. These genes function in a basal resistance pathway or in major disease resistance gene-mediated race-specific pathways.

  4. Metal Hyperaccumulation Armors Plants against Disease

    OpenAIRE

    Helen Fones; Calum A. R. Davis; Arantza Rico; Fang Fang; Smith, J. Andrew C.; Preston, Gail M.

    2010-01-01

    Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulation plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the 'elemental defense' hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a...

  5. Genes Expressed Differentially in Hessian Fly Larvae Feeding in Resistant and Susceptible Plants

    Directory of Open Access Journals (Sweden)

    Ming-Shun Chen

    2016-08-01

    Full Text Available The Hessian fly, Mayetiola destructor, is a destructive pest of wheat worldwide and mainly controlled by deploying resistant cultivars. In this study, we investigated the genes that were expressed differentially between larvae in resistant plants and those in susceptible plants through RNA sequencing on the Illumina platform. Informative genes were 11,832, 14,861, 15,708, and 15,071 for the comparisons between larvae in resistant versus susceptible plants for 0.5, 1, 3, and 5 days, respectively, after larvae had reached the feeding site. The transcript abundance corresponding to 5401, 6902, 8457, and 5202 of the informative genes exhibited significant differences (p ≤ 0.05 in the respective paired comparisons. Overall, genes involved in nutrient metabolism, RNA and protein synthesis exhibited lower transcript abundance in larvae from resistant plants, indicating that resistant plants inhibited nutrient metabolism and protein production in larvae. Interestingly, the numbers of cytochrome P450 genes with higher transcript abundance in larvae from resistant plants were comparable to, or higher than those with lower transcript abundance, indicating that toxic chemicals from resistant plants may have played important roles in Hessian fly larval death. Our study also identified several families of genes encoding secreted salivary gland proteins (SSGPs that were expressed at early stage of 1st instar larvae and with more genes with higher transcript abundance in larvae from resistant plants. Those SSGPs are candidate effectors with important roles in plant manipulation.

  6. Melhoramento visando a resistência do cafeeiro à ferrugem Breeding for resistance to leaf rust disease in C. arabica

    Directory of Open Access Journals (Sweden)

    A. J. Bettencourt

    1968-01-01

    Full Text Available A ferrugem alaranjada, uma das mais graves moléstias do cafeeiro, ainda não foi observada no continente americano. Com a mais freqüente e rápida ligação entre os países africanos e o Brasil, tem aumentado consideràvelmente o perigo de introdução neste continente. No presente trabalho, são fornecidos elementos sôbre a especialização fisiológica da H. vastatrix,fontes de resistência ao fungo, hereditariedade dessa resistência e dados já obtidos sôbre os fatôres de resistência que ocorrem nos cafeeiros existentes no Instituto Agronômico, em Campinas. Apresentam-se também as diretrizes para o prosseguimento do plano de melhoramento visando a obtenção de linhagens portadoras de fatôres genéticos que lhes proporcionem resistência ao maior número possível de raças da ferrugem.Coffee leaf rust, one of the most destructive diseases of this crop plant, does not occur in the American continent. However, the frequent commercial flights and the ever increasing speed of the planes that connect Africa and Brazil increase the probability of introduction of the disease into this continent. This paper reviews the characteristics of the coffee leaf rust fungus, Hemileia vastatrix, its physiological races and their geographic distribution, and the main sources of resistance already determined in Coffea spp.The genetic basis of the disease resistance is discussed and the collected, data indicate the presence of five pairs of genes for resistance in the imported coffee plants of the: Campinas collection. The breeding program which is being carried on at the Instituto Agronômico, Campinas, is discussed in regard to the isolation of coffee progenies resistant to the most known races of Hemileia vastatrix.

  7. Effects and Effectiveness of Two RNAi Constructs for Resistance to Pepper golden mosaic virus in Nicotiana benthamiana Plants

    Directory of Open Access Journals (Sweden)

    Diana Medina-Hernández

    2013-11-01

    Full Text Available ToChLPV and PepGMV are Begomoviruses that have adapted to a wide host range and are able to cause major diseases in agronomic crops. We analyzed the efficacy of induced resistance to PepGMV in Nicotiana benthamiana plants with two constructs: one construct with homologous sequences derived from PepGMV, and the other construct with heterologous sequences derived from ToChLPV. Plants protected with the heterologous construct showed an efficacy to decrease the severity of symptoms of 45%, while plants protected with the homologous construct showed an efficacy of 80%. Plants protected with the heterologous construct showed a reduction of incidence of 42.86%, while the reduction of incidence in plants protected with the homologous construct was 57.15%. The efficacy to decrease viral load was 95.6% in plants protected with the heterologous construct, and 99.56% in plants protected with the homologous construct. We found, in both constructs, up-regulated key components of the RNAi pathway. This demonstrates that the efficacy of the constructs was due to the activation of the gene silencing mechanism, and is reflected in the decrease of viral genome copies, as well as in recovery phenotype. We present evidence that both constructs are functional and can efficiently induce transient resistance against PepGMV infections. This observation guarantees a further exploration as a strategy to control complex Begomovirus diseases in the field.

  8. Stable integration and expression of a plant defensin in tomato confers resistance to fusarium wilt.

    Science.gov (United States)

    Abdallah, Naglaa A; Shah, Dilip; Abbas, Dina; Madkour, Magdy

    2010-01-01

    Plant defensins are small cysteine-rich peptides which belong to a group of pathogenasis related defense mechanism proteins. The proteins inhibit the growth of a broad range of microbes and are highly stable under extreme environmental stresses. Tomato cultivation is affected by fungal disease such as Fusarium wilt. In order to overcome fungal damages, transgenic tomato plants expressing the Medicago sativa defensin gene MsDef1 under the control of the CaMV 35S promoter were developed. The Fusarium-susceptible tomato (Lycobersicum esculentum Mill) cultivar CastleRock was used for transformation to acquire fungal resistance. Hypocotyl with a part of cotyledon (hypocotyledonary) for young tomato seedlings were used as an explant material and transformation was performed using the biolistic delivery system. Bombarded shoots were selected on regeneration medium supplemented with hygromycin and suitable concentrations of BA, zeatin ripozide and AgNO(3). Putative transgenic plantlets of T(0) were confirmed by PCR analysis using primers specific for the transgene and the transformation frequency obtained was 52.3%. Transformation and transcription of transgenes were confirmed in T(1) by PCR, Southern hybridizations, and reverse-transcription PCR (RT-PCR). The copy numbers of integrated transgene into tomato genome ranged between 1-3 copies. Greenhouse bioassay was performed on the transgenic T(1) and T(2) young seedlings and non-transgenic controls by challenging with a vigorous isolate of the fungal pathogen Fusarium oxysporum f. sp. Lycopersici. The level of fungal infectivity was determined using RT-PCR with tomatinase specific primers. Transgenic lines were more resistant to infection by fusarium than the control plants. These results indicated that overexpressing defensins in transgenic plants confer resistance to fungal pathogens.

  9. Climate change effects on plant disease: genomes to ecosystems.

    Science.gov (United States)

    Garrett, K A; Dendy, S P; Frank, E E; Rouse, M N; Travers, S E

    2006-01-01

    Research in the effects of climate change on plant disease continues to be limited, but some striking progress has been made. At the genomic level, advances in technologies for the high-throughput analysis of gene expression have made it possible to begin discriminating responses to different biotic and abiotic stressors and potential trade-offs in responses. At the scale of the individual plant, enough experiments have been performed to begin synthesizing the effects of climate variables on infection rates, though pathosystem-specific characteristics make synthesis challenging. Models of plant disease have now been developed to incorporate more sophisticated climate predictions. At the population level, the adaptive potential of plant and pathogen populations may prove to be one of the most important predictors of the magnitude of climate change effects. Ecosystem ecologists are now addressing the role of plant disease in ecosystem processes and the challenge of scaling up from individual infection probabilities to epidemics and broader impacts.

  10. Transgenic Paulownia Expressing shiva-1 Gene Has Increased Resistance to Paulownia Witches' Broom Disease

    Institute of Scientific and Technical Information of China (English)

    Tao DU; Yao WANG; Qin-Xue HU; Jie CHEN; Sheng LIU; Wen-Jin HUANG; Mu-Lan LIN

    2005-01-01

    Stem segments from diseased Paulownia tomentosa×P. fortunei and leaves from healthy control were transformed with the expression vector p438PRSI via Agrobacterium tumefaciens. The p438PRSI vector contained shiva-1 gene, which encodes an antibacterial peptide under the control of a CaMV35S promoter. The regenerated plants from transformed explants were planted in a greenhouse and nursery. PCR and Southern blotting analysis showed that the shiva-1 gene was successfully integrated into the Paulownia genome. Transcription of the integrated shiva-1 gene was confirmed by RT-PCR. Bioassay in the green house and phytoplasma DNA-dot blotting demonstrated that resistance to Paulownia witch's broom disease (PWB) increased significantly in shiva-1-transgenic Paulownia. Further investigations indicated that higher Shiva-1 expression correlated with fewer phytoplasma and less symptoms in diseased transgenic Paulownia. Together, our findings strongly suggest that breeding shiva-1-Paulownia is an effective strategy to control PWB disease.

  11. Marker-assisted selection for disease resistance in lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) is the most popular leafy vegetable that is cultivated mainly in moderate climate. Consumers demand lettuce with good visual appearance and free of disease. Improved disease resistance of new cultivars is achieved by combining desirable genes (or alleles) from existing cu...

  12. SSR Markers Assessed for Peanut Smut Disease Resistance

    Science.gov (United States)

    Peanut smut disease, caused by Thecaphora frezii (Carranza & Lindquist), can result in yield losses higher than 50%. Several strategies have been developed for disease management but they are still insufficient. The smut genetic resistance found in wild species and Bolivian landraces is currently th...

  13. Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

    Science.gov (United States)

    Zhang, Qian; Yang, Ruyi; Tang, Jianjun; Yang, Haishui; Hu, Shuijin; Chen, Xin

    2010-08-24

    Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

  14. Host mating system and the prevalence of a disease in a plant population

    Science.gov (United States)

    Koslow, Jennifer M.; DeAngelis, Donald L.

    2006-01-01

    A modified susceptible–infected–recovered (SIR) host–pathogen model is used to determine the influence of plant mating system on the outcome of a host–pathogen interaction. Unlike previous models describing how interactions between mating system and pathogen infection affect individual fitness, this model considers the potential consequences of varying mating systems on the prevalence of resistance alleles and disease within the population. If a single allele for disease resistance is sufficient to confer complete resistance in an individual and if both homozygote and heterozygote resistant individuals have the same mean birth and death rates, then, for any parameter set, the selfing rate does not affect the proportions of resistant, susceptible or infected individuals at equilibrium. If homozygote and heterozygote individual birth rates differ, however, the mating system can make a difference in these proportions. In that case, depending on other parameters, increased selfing can either increase or decrease the rate of infection in the population. Results from this model also predict higher frequencies of resistance alleles in predominantly selfing compared to predominantly outcrossing populations for most model conditions. In populations that have higher selfing rates, the resistance alleles are concentrated in homozygotes, whereas in more outcrossing populations, there are more resistant heterozygotes.

  15. A New Israeli Tobamovirus Isolate Infects Tomato Plants Harboring Tm-22 Resistance Genes.

    Science.gov (United States)

    Luria, Neta; Smith, Elisheva; Reingold, Victoria; Bekelman, Ilana; Lapidot, Moshe; Levin, Ilan; Elad, Nadav; Tam, Yehudit; Sela, Noa; Abu-Ras, Ahmad; Ezra, Nadav; Haberman, Ami; Yitzhak, Liron; Lachman, Oded; Dombrovsky, Aviv

    2017-01-01

    An outbreak of a new disease infecting tomatoes occurred in October-November 2014 at the Ohad village in Southern Israel. Symptomatic plants showed a mosaic pattern on leaves accompanied occasionally by narrowing of leaves and yellow spotted fruit. The disease spread mechanically and rapidly reminiscent of tobamovirus infection. Epidemiological studies showed the spread of the disease in various growing areas, in the South and towards the Southeast and Northern parts of the country within a year. Transmission electron microscope (TEM) analysis showed a single rod-like form characteristic to the Tobamovirus genus. We confirmed Koch's postulates for the disease followed by partial host range determination and revealed that tomato cultivars certified to harbor the Tm-22 resistance gene are susceptible to the new viral disease. We further characterized the viral source of the disease using a range of antisera for serological detection and analyzed various virus genera and families for cross-reactivity with the virus. In addition, next generation sequencing of total small RNA was performed on two cultivars grown in two different locations. In samples collected from commercial cultivars across Israel, we found a single virus that caused the disease. The complete genome sequence of the new Israeli tobamovirus showed high sequence identity to the Jordanian isolate of tomato brown rugose fruit virus.

  16. Functional analysis of an ubiquitin fusion degradation protein gene UFD1 in regulation of plant disease and stress resistance%泛素融合降解蛋白基因UFD1对植物抗病和抗逆性的调控功能分析

    Institute of Scientific and Technical Information of China (English)

    赖亿玉; 黎飞; 徐幼平; 蔡新忠

    2012-01-01

    A fragment of ubiquitin fusion degradation protein ( UFD) gene UFD1 was cloned from tomato by reverse transcription-polymerase chain reaction (RT-PCR), and its role in regulation of plant disease and stress resistance was analyzed employing virus-induced gene silencing (VIGS) technique. The results showed that the silencing of UFD1 in Nicotiana benthamiana resulted in significantly weakening of hypersensitive response (HR) mediated by Cf-4/Avr4- and Cf-9/Avr9 and induced by Xanthomonas oryzae pv. oryzae (Xoo), alleviating of necrotic symptoms of tobacco wild fire disease, decreasing of chlorophyll content in leaves under stress of high concentration of salt, but did not lead to change of symptoms of white mould disease caused by Sclerotinia sclerotiorum and resistance to drought stress.It is indicated that UFD1 is a pivotal regulator of plant disease and stress resistance, playing roles in positive regulation of Cf-4- and Cf-9-dependent gene-for-gene resistance, nonhost resistance to Xoo and salt tolerance, and in contrast, negative regulation of resistance to tobacco wild fire disease.%采用反转录-聚合酶链反应(reverse transcription-polymerase chain reaction,RT-PCR)克隆获得1个番茄泛素融合降解蛋白(ubiquitin fusion degradation protein,UFD)基因片段UFD1,并应用病毒诱导的基因沉默(virus-induced gene silencing,VIGS)技术分析该基因对植物抗病性和抗逆性的调控功能.结果表明:在本氏烟(Nicotiana benthamiana)植株中UFD1基因的沉默导致Cf-4/Avr4和Cf-9/Avr9介导的过敏性反应( hypersensitive response,HR)以及水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,Xoo)诱导的HR显著减弱,烟草野火病坏死症状明显减轻,在高盐胁迫下叶片叶绿素含量显著降低,但对菌核病病害症状以及抗干旱能力的影响不明显.表明UFD1基因是植物抗病和抗逆性的重要调控因子,它可能对Cf-4/Cf-9介导的基因对基因抗性、对Xoo的非寄主抗性和耐盐性起正

  17. Natural genetic and induced plant resistance, as a control strategy to plant-parasitic nematodes alternative to pesticides.

    Science.gov (United States)

    Molinari, Sergio

    2011-03-01

    Plant-parasitic nematodes are pests of a wide range of economically important crops, causing severe losses to agriculture. Natural genetic resistance of plants is expected to be a valid solution of the many problems nematodes cause all over the world. Progress in resistance applications is particularly important for the less-developed countries of tropical and subtropical regions, since use of resistant cultivars may be the only possible and economically feasible control strategy in those farming systems. Resistance is being considered of particular importance also in modern high-input production systems of developed countries, as the customary reliance on chemical nematicides has been restricted or has come to an end. This review briefly describes the genetic bases of resistance to nematodes in plants and focuses on the chances and problems of its exploitation as a key element in an integrated management program. Much space is dedicated to the major problem of resistance durability, in that the intensive use of resistant cultivars is likely to increasingly induce the selection of virulent populations able to "break" the resistance. Protocols of pest-host suitability are described, as bioassays are being used to evaluate local nematode populations in their potential to be selected on resistant germplasm and endanger resistant crops. The recent progress in using robust and durable resistances against nematodes as an efficient method for growers in vegetable cropping systems is reported, as well as the possible use of chemicals that do not show any unfavorable impact on environment, to induce in plants resistance against plant-parasitic nematodes.

  18. Germplasm modification and its potential for finding new sources of resistance to diseases.

    Science.gov (United States)

    Litz, R E

    1986-01-01

    In vitro procedures are playing a major role in plant breeding. Embryo rescue, either through the culture of excised embryos derived from incompatible crosses or by means of ovule culture, has been a standard procedure for the introgression of genes conferring disease resistance into economically important plants. Somatic hybridization (i.e., protoplast fusion) has also been demonstrated to have some potential in obtaining hybrids that result from very wide interspecific and intergeneric crosses. Wide crosses have also been achieved by means of in vitro pollination of excised ovaries or ovules. Tissue culture-induced variability in regenerated plant (i.e., somaclonal variation) appears to be an effective way of obtaining undirected genetic change that can enhance disease resistance and yield and alter the growth habit of crops that are normally propagated vegetatively (e.g., potato) or by seed (e.g., tomato). In the near future, the isolation and sequencing of genes that confer resistance to specific plant pathogens will be possible, and transfer of this information between species will become a reality.

  19. Exogenous application of methyl jasmonate induces a defense response and resistance against Sclerotinia sclerotiorum in dry bean plants.

    Science.gov (United States)

    Oliveira, Marília Barros; Junior, Murillo Lobo; Grossi-de-Sá, Maria Fátima; Petrofeza, Silvana

    2015-06-15

    Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen that causes a disease known as white mold, which is a major problem for dry bean (Phaseolus vulgaris L.) and other crops in many growing areas in Brazil. To investigate the role of methyl jasmonate (MeJA) in defending dry bean plants against S. sclerotiorum, we used suppression subtractive hybridization (SSH) of cDNA and identified genes that are differentially expressed during plant-pathogen interactions after treatment. Exogenous MeJA application enhanced resistance to the pathogen, and SSH analyses led to the identification of 94 unigenes, presumably involved in a variety of functions, which were classified into several functional categories, including metabolism, signal transduction, protein biogenesis and degradation, and cell defense and rescue. Using RT-qPCR, some unigenes were found to be differentially expressed in a time-dependent manner in dry bean plants during the interaction with S. sclerotiorum after MeJA treatment, including the pathogenesis-related protein PR3 (chitinase), PvCallose (callose synthase), PvNBS-LRR (NBS-LRR resistance-like protein), PvF-box (F-box family protein-like), and a polygalacturonase inhibitor protein (PGIP). Based on these expression data, the putative roles of differentially expressed genes were discussed in relation to the disease and MeJA resistance induction. Changes in the activity of the pathogenesis-related proteins β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase, and peroxidase in plants after MeJA treatment and following inoculation of the pathogen were also investigated as molecular markers of induced resistance. Foliar application of MeJA induced partial resistance against S. sclerotiorum in plants as well as a consistent increase in pathogenesis-related protein activities. Our findings provide new insights into the physiological and molecular mechanisms of resistance induced by MeJA in the P. vulgaris-S. sclerotiorum pathosystem

  20. Elicitation of Induced Resistance against Pectobacterium carotovorum and Pseudomonas syringae by Specific Individual Compounds Derived from Native Korean Plant Species

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-10-01

    Full Text Available Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species to determine whether they triggered induced resistance against Pectobacterium carotovorum supsp. carotovorum (Pcc in tobacco (Nicotiana tabacum and Pseudomonas syringae pv. tomato (Pst in Arabidopsis thaliana. To select target compound(s with direct and indirect (volatile effects, a new Petri-dish-based in vitro disease assay system with four compartments was developed. The screening assay showed that capsaicin, fisetin hydrate, jaceosidin, and farnesiferol A reduced the disease severity significantly in tobacco. Of these four compounds, capsaicin and jaceosidin induced resistance against Pcc and Pst, which depended on both salicylic acid (SA and jasmonic acid (JA signaling, using Arabidopsis transgenic and mutant lines, including npr1 and NahG for SA signaling and jar1 for JA signaling. The upregulation of the PR2 and PDF1.2 genes after Pst challenge with capsaicin pre-treatment indicated that SA and JA signaling were primed. These results demonstrate that capsaicin and jaceosidin can be effective triggers of strong induced resistance against both necrotrophic and biotrophic plant pathogens.

  1. Non-smooth plant disease models with economic thresholds.

    Science.gov (United States)

    Zhao, Tingting; Xiao, Yanni; Smith, Robert J

    2013-01-01

    In order to control plant diseases and eventually maintain the number of infected plants below an economic threshold, a specific management strategy called the threshold policy is proposed, resulting in Filippov systems. These are a class of piecewise smooth systems of differential equations with a discontinuous right-hand side. The aim of this work is to investigate the global dynamic behavior including sliding dynamics of one Filippov plant disease model with cultural control strategy. We examine a Lotka-Volterra Filippov plant disease model with proportional planting rate, which is globally studied in terms of five types of equilibria. For one type of equilibrium, the global structure is discussed by the iterative equations for initial numbers of plants. For the other four types of equilibria, the bounded global attractor of each type is obtained by constructing appropriate Lyapunov functions. The ideas of constructing Lyapunov functions for Filippov systems, the methods of analyzing such systems and the main results presented here provide scientific support for completing control regimens on plant diseases in integrated disease management. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Activation of Pathogenesis-related Genes by the Rhizobacterium, Bacillus sp. JS, Which Induces Systemic Resistance in Tobacco Plants

    Directory of Open Access Journals (Sweden)

    Ji-Seong Kim

    2015-06-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding β-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression.

  3. Inheritance of resistance to cotton blue disease Herança da resistência do algodoeiro à doença-azul

    Directory of Open Access Journals (Sweden)

    Osmério Pupim Junior

    2008-05-01

    Full Text Available The objective of this work was to determine the inheritance of cotton blue disease resistance by cotton plants. Populations derived from the CD 401 and Delta Opal resistant varieties were evaluated, through a greenhouse test with artificial inoculation by viruliferous aphids. Cotton blue disease resistance is conditioned by one dominant gene, both in CD 401 and Delta Opal varieties.O objetivo deste trabalho foi determinar a herança da resistência do algodoeiro à doença-azul. Populações derivadas das variedades resistentes CD 401 e Delta Opal foram avaliadas em casa de vegetação, por meio da inoculação de pulgões virulíferos. A resistência à doença-azul do algodoeiro é condicionada por um gene dominante, tanto em 'DC 401' quanto em 'Delta Opal'.

  4. Plant disease management in organic farming systems.

    Science.gov (United States)

    van Bruggen, Ariena H C; Gamliel, Abraham; Finckh, Maria R

    2016-01-01

    Organic farming (OF) has significantly increased in importance in recent decades. Disease management in OF is largely based on the maintenance of biological diversity and soil health by balanced crop rotations, including nitrogen-fixing and cover crops, intercrops, additions of manure and compost and reductions in soil tillage. Most soil-borne diseases are naturally suppressed, while foliar diseases can sometimes be problematic. Only when a severe disease outbreak is expected are pesticides used that are approved for OF. A detailed overview is given of cultural and biological control measures. Attention is also given to regulated pesticides. We conclude that a systems approach to disease management is required, and that interdisciplinary research is needed to solve lingering disease problems, especially for OF in the tropics. Some of the organic regulations are in need of revision in close collaboration with various stakeholders.

  5. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

    Directory of Open Access Journals (Sweden)

    Wei Yang

    Full Text Available Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA-dependent pathway from an early stage upstream of NDR1 and EDS1.

  6. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

    Science.gov (United States)

    Yang, Wei; Xu, Xiaonan; Li, Yang; Wang, Yingzi; Li, Ming; Wang, Yong; Ding, Xinhua; Chu, Zhaohui

    2016-01-01

    Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA)-dependent pathway from an early stage upstream of NDR1 and EDS1.

  7. Molecular markers for resistance against infectious diseases of economic importance

    Science.gov (United States)

    Prajapati, B. M.; Gupta, J. P.; Pandey, D. P.; Parmar, G. A.; Chaudhari, J. D.

    2017-01-01

    Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne’s disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA­-DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically

  8. Review of aspirin and clopidogrel resistance in peripheral arterial disease.

    Science.gov (United States)

    Guirgis, Mina; Thompson, Peter; Jansen, Shirley

    2017-09-08

    Aspirin resistance (AR) and clopidogrel resistance (CR) are terms used to describe a reduction in the medication's efficacy in inhibiting platelet aggregation despite regular dosing. This review gives context to the clinical role and implications of antiplatelet resistance in peripheral arterial disease (PAD). A review of English-language literature on AR and CR in PAD involving human subjects using PubMed and MEDLINE databases was performed in April 2017. A total of 2075 patients in 22 relevant studies were identified. To give this issue context, a review of the larger, more established literature on antiplatelet resistance in coronary disease was undertaken, identifying significant research associating resistance to major adverse cardiovascular events (MACEs). Studies in the coronary arterial disease literature have strongly associated antiplatelet resistance with increased MACE. Prevalence of AR or CR in coronary disease appears to be >55% for each in some studies. Meta-analyses of >50 studies revealed that AR and CR are significantly associated with MACE (relative risk of 2.09 and 2.8, respectively). This adds further weight to the literature reporting antiplatelet resistance as an independent predictor of and a threefold risk factor for major adverse cardiovascular events. The prevalence of resistance in PAD in this review was comparable to that in the coronary disease literature, with AR and CR prevalence up to 60% and 65%, respectively. There is evidence that the adverse effects of antiplatelet resistance are significant in PAD. In fact, research directly studying stent thrombosis populations with either coronary arterial disease or PAD revealed more significantly impaired platelet responsiveness to clopidogrel and aspirin in PAD compared with similar individuals with coronary disease. AR in PAD was found in studies to be a significant risk factor for iliofemoral stent reocclusion (P = .0093) and stroke in patients with symptomatic carotid disease (P

  9. Enhancement of the citrus immune system provides effective resistance against Alternaria brown spot disease.

    Science.gov (United States)

    Llorens, Eugenio; Fernández-Crespo, Emma; Vicedo, Begonya; Lapeña, Leonor; García-Agustín, Pilar

    2013-01-15

    In addition to basal defense mechanisms, plants are able to develop enhanced defense mechanisms such as induced resistance (IR) upon appropriate stimulation. We recently described the means by which several carboxylic acids protect Arabidopsis and tomato plants against fungi. In this work, we demonstrate the effectiveness of hexanoic acid (Hx) in the control of Alternaria brown spot (ABS) disease via enhancement of the immune system of Fortune mandarin. The application of 1mM Hx in irrigation water to 2-year-old Fortune plants clearly reduced the incidence of the disease and led to smaller lesions. We observed that several of the most important mechanisms involved in induced resistance were affected by Hx application. Our results demonstrate enhanced callose deposition in infected plants treated with Hx, which suggests an Hx priming mechanism. Plants treated with the callose inhibitor 2-DDG were more susceptible to the fungus. Moreover, polygalacturonase-inhibiting protein (PGIP) gene expression was rapidly and significantly upregulated in treated plants. However, treatment with Hx decreased the levels of reactive oxygen species (ROS) in infected plants. Hormonal and gene analyses revealed that the jasmonic acid (JA) pathway was activated due to a greater accumulation of 12-oxo-phytodienoic acid (OPDA) and JA along with a rapid accumulation of JA-isoleucine (JA-Ile). Furthermore, we observed a more rapid accumulation of abscisic acid (ABA), which could act as a positive regulator of callose deposition. Thus, our results support the hypothesis that both enhanced physical barriers and the JA signaling pathway are involved in hexanoic acid-induced resistance (Hx-IR) to Alternaria alternata.

  10. Plant-microbe interactions and the new biotechnological methods of plant disease control.

    Science.gov (United States)

    Montesinos, E; Bonaterra, A; Badosa, E; Francés, J; Alemany, J; Llorente, I; Moragrega, C

    2002-12-01

    Plants constitute an excellent ecosystem for microorganisms. The environmental conditions offered differ considerably between the highly variable aerial plant part and the more stable root system. Microbes interact with plant tissues and cells with different degrees of dependence. The most interesting from the microbial ecology point of view, however, are specific interactions developed by plant-beneficial (either non-symbiotic or symbiotic) and pathogenic microorganisms. Plants, like humans and other animals, also become sick, but they have evolved a sophisticated defense response against microbes, based on a combination of constitutive and inducible responses which can be localized or spread throughout plant organs and tissues. The response is mediated by several messenger molecules that activate pathogen-responsive genes coding for enzymes or antimicrobial compounds, and produces less sophisticated and specific compounds than immunoglobulins in animals. However, the response specifically detects intracellularly a type of protein of the pathogen based on a gene-for-gene interaction recognition system, triggering a biochemical attack and programmed cell death. Several implications for the management of plant diseases are derived from knowledge of the basis of the specificity of plant-bacteria interactions. New biotechnological products are currently being developed based on stimulation of the plant defense response, and on the use of plant-beneficial bacteria for biological control of plant diseases (biopesticides) and for plant growth promotion (biofertilizers).

  11. Fungal Biofilms: Targets for the Development of Novel Strategies in Plant Disease Management.

    Science.gov (United States)

    Villa, Federica; Cappitelli, Francesca; Cortesi, Paolo; Kunova, Andrea

    2017-01-01

    The global food supply has been facing increasing challenges during the first decades of the 21(st) century. Disease in plants is an important constraint to worldwide crop production, accounting for 20-40% of its annual harvest loss. Although the use of resistant varieties, good water management and agronomic practices are valid management tools in counteracting plant diseases, there are still many pathosystems where fungicides are widely used for disease management. However, restrictive regulations and increasing concern regarding the risk to human health and the environment, along with the incidence of fungicide resistance, have discouraged their use and have prompted for a search for new efficient, ecologically friendly and sustainable disease management strategies. The recent evidence of biofilm formation by fungal phytopathogens provides the scientific framework for designing and adapting methods and concepts developed by biofilm research that could be integrated in IPM practices. In this perspective paper, we provide evidence to support the view that the biofilm lifestyle plays a critical role in the pathogenesis of plant diseases. We describe the main factors limiting the durability of single-site fungicides, and we assemble the current knowledge on pesticide resistance in the specific context of the biofilm lifestyle. Finally, we illustrate the potential of antibiofilm compounds at sub-lethal concentrations for the development of an innovative, eco-sustainable strategy to counteract phytopathogenic fungi. Such fungicide-free solutions will be instrumental in reducing disease severity, and will permit more prudent use of fungicides decreasing thus the selection of resistant forms and safeguarding the environment.

  12. Engineering Plants for Geminivirus Resistance with CRISPR/Cas9 System.

    Science.gov (United States)

    Zaidi, Syed Shan-E-Ali; Mansoor, Shahid; Ali, Zahir; Tashkandi, Manal; Mahfouz, Magdy M

    2016-04-01

    The CRISPR/Cas9 system is an efficient genome-editing platform for diverse eukaryotic species, including plants. Recent work harnessed CRISPR/Cas9 technology to engineer resistance to geminiviruses. Here, we discuss opportunities, emerging developments, and potential pitfalls for using this technology to engineer resistance against single and multiple geminivirus infections in plants.

  13. Engineering Plants for Geminivirus Resistance with CRISPR/Cas9 System

    KAUST Repository

    Zaidi, Syed Shan-e-Ali

    2016-02-14

    The CRISPR/Cas9 system is an efficient genome-editing platform for diverse eukaryotic species, including plants. Recent work harnessed CRISPR/Cas9 technology to engineer resistance to geminiviruses. Here, we discuss opportunities, emerging developments, and potential pitfalls for using this technology to engineer resistance against single and multiple geminivirus infections in plants.

  14. Genes Expressed Differentially in Hessian Fly Larvae Feeding in Resistant and Susceptible Plants

    Science.gov (United States)

    The Hessian fly, Mayetiola destructor, is a destructive pest of wheat worldwide and mainly controlled by deploying resistant cultivars. Hessian fly larvae manipulate susceptible plants extensively, but are unable to manipulate resistant plants and thus die in them. The mechanisms for Hessian fly l...

  15. The in-vitro antimicrobial activity of some medicinal plants against beta-lactam-resistant bacteria

    OpenAIRE

    Gangoue Pieboji, Joseph; Eze, N.; Ngongang Djintchui, A.; Ngameni, B; Tsabang, N.; Pegnyemb, D. E.; Biyiti, L.; Ngassam, P.; Koulla-Shiro, S.; Galleni, Moreno

    2009-01-01

    BACKGROUND: In effort to identify novel bacterial agents, this study was initiated to evaluate the antimicrobial properties of 17 crude extracts from 12 medicinal plants against beta-lactam-resistant bacteria. METHODOLOGY: The antimicrobial activities of plant extracts were evaluated against clinically proved beta-lactam-resistant bacteria (Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus and Enterococcus sp.)...

  16. Direct interaction between the Arabidopsis disease resistance signaling proteins, EDS1 and PAD4.

    Science.gov (United States)

    Feys, B J; Moisan, L J; Newman, M A; Parker, J E

    2001-10-01

    The Arabidopsis EDS1 and PAD4 genes encode lipase-like proteins that function in resistance (R) gene-mediated and basal plant disease resistance. Phenotypic analysis of eds1 and pad4 null mutants shows that EDS1 and PAD4 are required for resistance conditioned by the same spectrum of R genes but fulfil distinct roles within the defence pathway. EDS1 is essential for elaboration of the plant hypersensitive response, whereas EDS1 and PAD4 are both required for accumulation of the plant defence-potentiating molecule, salicylic acid. EDS1 is necessary for pathogen-induced PAD4 mRNA accumulation, whereas mutations in PAD4 or depletion of salicylic acid only partially compromise EDS1 expression. Yeast two-hybrid analysis reveals that EDS1 can dimerize and interact with PAD4. However, EDS1 dimerization is mediated by different domains to those involved in EDS1-PAD4 association. Co-immunoprecipitation experiments show that EDS1 and PAD4 proteins interact in healthy and pathogen-challenged plant cells. We propose two functions for EDS1. The first is required early in plant defence, independently of PAD4. The second recruits PAD4 in the amplification of defences, possibly by direct EDS1-PAD4 association.

  17. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  18. Impacts of thiamethoxam seed treatment and host plant resistance on the soybean aphid fungal pathogen, Pandora neoaphidis.

    Science.gov (United States)

    Koch, Karrie A; Ragsdale, David W

    2011-12-01

    Since the introduction of soybean aphid, Aphis glycines Matsumura, from Asia, insecticide use in soybean has increased substantially in the north central United States. Insecticide seed treatments and aphid resistant soybean varieties are management tactics that may reduce reliance on foliar applications of broad-spectrum insecticides. Exploring potential nontarget impacts of these technologies will be an important step in incorporating them into aphid management programs. We investigated impacts of thiamethoxam seed treatment and Rag1 aphid resistant soybean on a fungal pathogen of soybean aphid, Pandora neoaphidis (Remaudière & Hennebert) Humber, via open plot and cage studies. We found that although thiamethoxam seed treatment did significantly lower aphid pressure in open plots compared with an untreated control, this reduction in aphid density translated into nonsignificant decreases in fungal disease prevalence in aphids. Furthermore, when aphid densities were approximately equal in seed treated and untreated soybean, no impact on aphid fungal disease was observed. In open plots, Rag1 resistant soybean experienced lower aphid pressure and aphid disease prevalence compared with a nonresistant isoline. However, in cages when aphid densities were equivalent in both resistant and susceptible soybean, resistance had no impact on aphid disease prevalence. The addition of thiamethoxam seed treatment to resistant soybean yielded aphid densities and aphid disease prevalence similar to untreated, resistant soybean. These studies provide evidence that thiamethoxam seed treatments and Rag1 resistance can impact P. neoaphidis via decreased aphid densities; however, this impact is minimal, implying use of seed treatments and host plant resistance are compatible with P. neoaphidis.

  19. Identification and Classification of Leaf Diseases in Turmeric Plants

    Directory of Open Access Journals (Sweden)

    Nandhini M,

    2016-02-01

    Full Text Available Plant disease identification is the most important sector in agriculture. Turmeric is one of the important rhizomatous crops grown in India. The turmeric leaf is highly exposed to diseases like rhizome rot, leaf spot, and leaf blotch. The identification of plant diseases requires close monitoring and hence this paper adopts technologies to manage turmeric plant diseases caused by fungi to enable production of high quality crop yields. Various image processing and machine learning techniques are used to identify and classify the diseases in turmeric leaf. The dataset with 800 leaf images of different categories were pre-processed and segmented to promote efficient feature extraction. Machine learning algorithms like support vector machine, decision tree and naïve bayes were applied to train the model. The performance of the model was evaluated using 10 fold cross validation and the results are reported.

  20. Plant-based oral vaccines against zoonotic and non-zoonotic diseases.

    Science.gov (United States)

    Shahid, Naila; Daniell, Henry

    2016-11-01

    The shared diseases between animals and humans are known as zoonotic diseases and spread infectious diseases among humans. Zoonotic diseases are not only a major burden to livestock industry but also threaten humans accounting for >60% cases of human illness. About 75% of emerging infectious diseases in humans have been reported to originate from zoonotic pathogens. Because antibiotics are frequently used to protect livestock from bacterial diseases, the development of antibiotic-resistant strains of epidemic and zoonotic pathogens is now a major concern. Live attenuated and killed vaccines are the only option to control these infectious diseases and this approach has been used since 1890. However, major problems with this approach include high cost and injectable vaccines is impractical for >20 billion poultry animals or fish in aquaculture. Plants offer an attractive and affordable platform for vaccines against animal diseases because of their low cost, and they are free of attenuated pathogens and cold chain requirement. Therefore, several plant-based vaccines against human and animals diseases have been developed recently that undergo clinical and regulatory approval. Plant-based vaccines serve as ideal booster vaccines that could eliminate multiple boosters of attenuated bacteria or viruses, but requirement of injectable priming with adjuvant is a current limitation. So, new approaches like oral vaccines are needed to overcome this challenge. In this review, we discuss the progress made in plant-based vaccines against zoonotic or other animal diseases and future challenges in advancing this field. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Fitness Costs Associated with Evolved Herbicide Resistance Alleles in Plants

    National Research Council Canada - National Science Library

    Martin M. Vila-Aiub; Paul Neve; Stephen B. Powles

    2009-01-01

    .... There have been many studies quantifying the fitness costs associated with novel herbicide resistance alleles, reflecting the importance of fitness costs in determining the evolutionary dynamics of resistance...

  2. Presence of Methicillin Resistant Staphylococcus aureus (MRSA) in sewage treatment plant.

    Science.gov (United States)

    Boopathy, Raj

    2017-09-01

    The presence of antibiotic resistant bacteria and antibiotic resistance genes in rural sewage treatment plants are not well reported in the literature. The aim of the present study was to study the frequency occurrence of Methicillin Resistant Staphylococcus aureus (MRSA) in a rural sewage treatment plant. This study was conducted using raw sewage as well as treated sewage from a small town sewage treatment plant in rural southeast Louisiana of USA. Results showed the presence of MRSA consistently in both raw and treated sewage. The presence of mecA gene responsible for methicillin resistance was confirmed in the raw and treated sewage water samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Genetic and sexual separation between insect resistant and susceptible Barbarea vulgaris plants in Denmark

    DEFF Research Database (Denmark)

    Toneatto, Fiorello; Nielsen, Jens Kvist; Ørgaard, Marian

    2010-01-01

    . In the cruciferous plant Barbarea vulgaris, some Danish individuals are resistant to herbivory by flea beetles (Phyllotreta nemorum), whereas others are not. The flea beetles are, in parallel, either resistant or susceptible to the plants defenses. To understand the historical-evolutionary framework...... was determined by analysis of molecular markers. Resistant and susceptible Danish plants were genetically strongly differentiated and produced significantly fewer hybrids than expected from random mating or nearest neighbour mating. Our results suggest that the two types belong to different evolutionary lineages...... regions. If so, resistance and susceptibility has for unknown reasons become associated with the different evolutionary lineages....

  4. Order of arrival shifts endophyte-pathogen interactions in bean from resistance induction to disease facilitation.

    Science.gov (United States)

    Adame-Álvarez, Rosa-María; Mendiola-Soto, Jaime; Heil, Martin

    2014-06-01

    Endophytic fungi colonize plants without causing symptoms of disease and can enhance the resistance of their host to pathogens. We cultivated 53 fungal strains from wild lima bean (Phaseolus lunatus) and investigated their effects on pathogens using in vitro assays and experiments in planta. Most strains were annotated as Rhizopus, Fusarium, Penicillium, Cochliobolus, and Artomyces spp. by the sequence of their 18S rRNA gene. In vitro confrontation assays between endophytes and three pathogens (the bacteria Pseudomonas syringae pv. syringae and Enterobacter sp. strain FCB1, and the fungus Colletotrichum lindemuthianum) revealed strong and mainly symmetric reciprocal effects: endophyte and pathogen either mutually inhibited (mainly Enterobacter FCB1 and Colletotrichum) or facilitated (P. syringae) the growth of each other. In planta, the endophytes had a strong inhibitory effect on P. syringae when they colonized the plant before the bacterium, whereas infection was facilitated when P. syringae colonized the plant before the endophyte. Infection with Enterobacter FCB1 was facilitated when the bacterium colonized the plant before or on the same day with the endophyte, but not when the endophyte was present before the bacterium. The order of arrival determines whether fungal endophytes enhance plant resistance to bacterial pathogens or facilitate disease.

  5. Antimicrobial Peptides: Insights into Membrane Permeabilization, Lipopolysaccharide Fragmentation and Application in Plant Disease Control

    OpenAIRE

    Datta, A.; Ghosh, A; Airoldi, C; Sperandeo, P; Mroue, K; Jimenez-Barbero, J; Kundu, P.; Ramamoorthy, A; Bhunia, A

    2015-01-01

    The recent increase in multidrug resistance against bacterial infections has become a major concern to human health and global food security. Synthetic antimicrobial peptides (AMPs) have recently received substantial attention as potential alternatives to conventional antibiotics because of their potent broad-spectrum antimicrobial activity. These peptides have also been implicated in plant disease control for replacing conventional treatment methods that are polluting and hazardous to the en...

  6. Construction of a new plant expression vector containing two insect resistant genes and its expression in transgenic tobacco plants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new plant expression vector (pBS29K-BA) containing two insect resistant genes, a synthetic chimeric gene BtS29K encoding the activated insecticidal protein Cry1Ac and a gene API-BA encoding the arrowhead (Sagittaria sagittifolia L.) proteinase inhibitor (API) A and B, is constructed. Transgenic tobacco plants expressing these two genes are obtained through Agrobacterium-mediated transformation of tobacco leaf discs. The average expression levels of Cry1Ac and API-BA proteins in transgenic plants are of 3.2 μg and 4.9 μg per gram fresh leaf respectively. The results of insecticidal assay of transgenic plants indicate that the pBS29K-BA transformed plants are more resistant to insect damage than the plants expressing the Cry1Ac gene or API-BA gene alone.

  7. Mechanisms linking brain insulin resistance to Alzheimer's disease

    OpenAIRE

    Maria Niures P.S. Matioli; Ricardo Nitrini

    2015-01-01

    Several studies have indicated that Diabetes Mellitus (DM) can increase the risk of developing Alzheimer's disease (AD). This review briefly describes current concepts in mechanisms linking DM and insulin resistance/deficiency to AD. Insulin/insulin-like growth factor (IGF) resistance can contribute to neurodegeneration by several mechanisms which involve: energy and metabolism deficits, impairment of Glucose transporter-4 function, oxidative and endoplasmic reticulum stress, mitochondrial dy...

  8. 氨基寡糖素对贡柑抗病增产品质改善作用的研究%Study on Plant Immunity Inducer Oligosaccharins on Disease Resistant, Yield Increase, and Improving Quality of Citrus Gonggan

    Institute of Scientific and Technical Information of China (English)

    陆红霞; 周文静; 黄不谎; 蓝亿亿; 王会民; 杜公福

    2014-01-01

    1.4% and 10.3% separately, per fruit weight are 108.17g and 86.85g separately, the weight gain rate increase to 24.55%. The fruit surface is smooth and uniform coloring with Oligosaccharins-spraying treated, thus the fruit quality is improved. The acidity degrade by 12.05%, the content of Vc rise about 29.74% with Oligosaccharins-spraying treated, which are significantly different through square error analysis. The tests illustrated that Oligosaccharins treatment can improve disease resistance and the quality of the compound, and the production was increased.

  9. Nationwide Surveillance of Azole Resistance in Aspergillus Diseases.

    Science.gov (United States)

    Vermeulen, Edith; Maertens, Johan; De Bel, Annelies; Nulens, Eric; Boelens, Jerina; Surmont, Ignace; Mertens, Anna; Boel, An; Lagrou, Katrien

    2015-08-01

    Aspergillus disease affects a broad patient population, from patients with asthma to immunocompromised patients. Azole resistance has been increasingly reported in both clinical and environmental Aspergillus strains. The prevalence and clinical impact of azole resistance in different patient populations are currently unclear. This 1-year prospective multicenter cohort study aimed to provide detailed epidemiological data on Aspergillus resistance among patients with Aspergillus disease in Belgium. Isolates were prospectively collected in 18 hospitals (April 2011 to April 2012) for susceptibility testing. Clinical and treatment data were collected with a questionnaire. The outcome was evaluated to 1 year after a patient's inclusion. A total of 220 Aspergillus isolates from 182 patients were included. The underlying conditions included invasive aspergillosis (n = 122 patients), allergic bronchopulmonary aspergillosis (APBA) (n = 39 patients), chronic pulmonary aspergillosis (n = 10 patients), Aspergillus bronchitis (n = 7 patients), and aspergilloma (n = 5 patients). The overall azole resistance prevalence was 5.5% (95% confidence interval [CI] 2.8 to 10.2%) and was 7.0% (4/57; 95% CI, 2.3 to 17.2%) in patients with APBA, bronchitis, aspergilloma, or chronic aspergillosis and 4.6% in patients with invasive aspergillosis (5/108; 95% CI, 1.7 to 10.7%). The 6-week survival in invasive aspergillosis was 52.5%, while susceptibility testing revealed azole resistance in only 2/58 of the deceased patients. The clinical impact of Aspergillus fumigatus resistance was limited in our patient population with Aspergillus diseases.

  10. POSSIBILITY OF PLANTS ACTIVE PARTS USAGE FOR ONCOLOGICAL DISEASES TREATMENT

    Directory of Open Access Journals (Sweden)

    T. S. Goncharova

    2015-01-01

    Full Text Available The article describes an implementation of plant drugs for oncological diseases treatment. It focuses on multicomponent combination herbal medicinal preparation, its therapeutic action, and supposed efficiency during its implementation with basic therapy for oncological disease.

  11. Reiterative and interruptive signaling in induced plant resistance to chewing insects.

    Science.gov (United States)

    Kim, Jinwon; Quaghebeur, Hélène; Felton, Gary W

    2011-09-01

    Our understanding of induced resistance against herbivores has grown immeasurably during the last several decades. Based upon the emerging literature, we argue that induced resistance represents a continuum of phenotypes that is determined by the plant's ability to integrate multiple suites of signals of plant and herbivore origin. We present a model that illustrates the range of signals arising from early detection through herbivore feeding, and then through subsequent plant generations.

  12. The hypersensitive induced reaction and leucine-rich repeat proteins regulate plant cell death associated with disease and plant immunity.

    Science.gov (United States)

    Choi, Hyong Woo; Kim, Young Jin; Hwang, Byung Kook

    2011-01-01

    Pathogen-induced programmed cell death (PCD) is intimately linked with disease resistance and susceptibility. However, the molecular components regulating PCD, including hypersensitive and susceptible cell death, are largely unknown in plants. In this study, we show that pathogen-induced Capsicum annuum hypersensitive induced reaction 1 (CaHIR1) and leucine-rich repeat 1 (CaLRR1) function as distinct plant PCD regulators in pepper plants during Xanthomonas campestris pv. vesicatoria infection. Confocal microscopy and protein gel blot analyses revealed that CaLRR1 and CaHIR1 localize to the extracellular matrix and plasma membrane (PM), respectively. Bimolecular fluorescent complementation and coimmunoprecipitation assays showed that the extracellular CaLRR1 specifically binds to the PM-located CaHIR1 in pepper leaves. Overexpression of CaHIR1 triggered pathogen-independent cell death in pepper and Nicotiana benthamiana plants but not in yeast cells. Virus-induced gene silencing (VIGS) of CaLRR1 and CaHIR1 distinctly strengthened and compromised hypersensitive and susceptible cell death in pepper plants, respectively. Endogenous salicylic acid levels and pathogenesis-related gene transcripts were elevated in CaHIR1-silenced plants. VIGS of NbLRR1 and NbHIR1, the N. benthamiana orthologs of CaLRR1 and CaHIR1, regulated Bax- and avrPto-/Pto-induced PCD. Taken together, these results suggest that leucine-rich repeat and hypersensitive induced reaction proteins may act as cell-death regulators associated with plant immunity and disease.

  13. Embedded mobile farm robot for identification of diseased plants

    Science.gov (United States)

    Sadistap, S. S.; Botre, B. A.; Pandit, Harshavardhan; Chandrasekhar; Rao, Adesh

    2013-07-01

    This paper presents the development of a mobile robot used in farms for identification of diseased plants. It puts forth two of the major aspects of robotics namely automated navigation and image processing. The robot navigates on the basis of the GPS (Global Positioning System) location and data obtained from IR (Infrared) sensors to avoid any obstacles in its path. It uses an image processing algorithm to differentiate between diseased and non-diseased plants. A robotic platform consisting of an ARM9 processor, motor drivers, robot mechanical assembly, camera and infrared sensors has been used. Mini2440 microcontroller has been used wherein Embedded linux OS (Operating System) is implemented.

  14. Inverted-repeat transgenic maize plants resistant to sugarcane mosaic virus

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    RNA silencing is a post-transcriptional genesilencing phenomenon induced by double-stranded RNA (dsRNA).In an attempt to generate dsRNA-mediated transgenic maize plants resistant to sugarcane mosaic virus (SCMV),we cloned SCMV Nib gene-specificsequences and inserted it into the binary vector p3301 in the sense and antisense orientations (named SCMVir-Nib),which could produce RNAs capable of duplex formation in plant cells.Maize immature embryos were co-cultured with Agrobacterium carrying two vectors,one marker-free vector harboring the SCMVirNIb and one vector harboring bar gene as the selective marker.Resistant calli were recovered by selection on medium containing Biolaphos.Among the regenerated plantlets from resistant calli,14 plants have been certified to contain SCMVirNIb by PCR amplification and DNA dot blot.T1 plants derived from the 14 plants were challenged in a greenhouse with SCMV inoculums and the percentages of resistant plants in 11 T1 lines were higher than 60%.One plant in the T1 line was found to carry SCMVirNIb without bar gene by PCR assay.T2 plants derived from T1 SCMV resistant transgenic plants were challenged with SCMV inoculums in field.The percentages of resistant plants from 3 lines,including the line derived from the marker-free transgenic plant,were higher than 85%.The non-transgenic control plants were all susceptible.Further molecular analysis confirmed that the resistant plants from the marker-free transgenic line contained SCMVirNIb but not the bar gene.

  15. Prevalence and antimicrobial resistance of Salmonella isolated from two pork processing plants in Alberta, Canada.

    Science.gov (United States)

    Sanchez-Maldonado, Alma Fernanda; Aslam, Mueen; Service, Cara; Narváez-Bravo, Claudia; Avery, Brent P; Johnson, Roger; Jones, Tineke H

    2017-01-16

    This study investigated the frequency of Salmonella serovars on pig carcasses at various processing steps in two commercial pork processing plants in Alberta, Canada and characterized phenotypic and genotypic antimicrobial resistance (AMR) and PFGE patterns of the Salmonella isolates. Over a one year period, 1000 swab samples were collected from randomly selected pigs at two slaughter plants. Sampling points were: carcass swabs after bleeding (CSAB), carcass swabs after de-hairing (CSAD, plant A) or skinning (CSASk, plant B), carcass swabs after evisceration (CSAE), carcass swabs after pasteurization (CSAP, plant A) or washing (CSAW, plants B) and retail pork (RP). For plant A, 87% of CSAB and 8% of CSAE were positive for Salmonella while at plant B, Salmonella was recovered from 94% of CSAB and 10% of CSAE. Salmonella was not recovered from the RP samples at either plant, indicating that the plants used effective control measures. Salmonella enterica serovar Derby was the most common serotype (23%, 29/127) recovered in plant A and plant B (61%, 76/124). For plant A, 35% (45/127) of isolates were resistant to at least one antimicrobial. Five isolates (3.9%), 4 serovar Ohio strains and one serovar I:Rough-O:I,v:-, strain were simultaneously resistant to antimicrobials of very high (Category I), high (Category II), and medium (Category III) importance to human medicine. The 4 S. Ohio isolates were recovered from 3 different steps of pork processing on the same sampling day and displayed resistance to 5-7 antimicrobials, with all of them displaying resistance to ceftiofur and ceftriaxone (Category I). An I:Rough-O:l,v:- isolate, recovered on a different sampling day, was resistant to 7 antimicrobials that included resistance to ampicillin/clavulanic acid, ceftiofur and ceftriaxone (Category I). Salmonella strains isolated from plant A harbored 12 different AMR genes. The most prevalent genes were sul1, sul2, tet(A), tet(B), aadA, strA/strB, aac(3)IV and aphA1. For

  16. Interplay Between Antibiotic Resistance and Virulence During Disease Promoted by Multidrug-Resistant Bacteria.

    Science.gov (United States)

    Geisinger, Edward; Isberg, Ralph R

    2017-02-15

    Diseases caused by antibiotic-resistant bacteria in hospitals are the outcome of complex relationships between several dynamic factors, including bacterial pathogenicity, the fitness costs of resistance in the human host, and selective forces resulting from interventions such as antibiotic therapy. The emergence and fate of mutations that drive antibiotic resistance are governed by these interactions. In this review, we will examine how different forms of antibiotic resistance modulate bacterial fitness and virulence potential, thus influencing the ability of pathogens to evolve in the context of nosocomial infections. We will focus on 3 important multidrug-resistant pathogens that are notoriously problematic in hospitals: Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. An understanding of how antibiotic resistance mutations shape the pathobiology of multidrug-resistant infections has the potential to drive novel strategies that can control the development and spread of drug resistance. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, email: journals.permissions@oup.com.

  17. A single recessive gene conferring short leaves in romaine x Latin type lettuce (Lactuca sativa L.) crosses, and its effect on plant morphology and resistance to lettuce drop caused by Sclerotinia minor Jagger.

    Science.gov (United States)

    Understanding the relationship between plant morphology and disease resistance is crucial to successful breeding, particularly resistance to lettuce drop caused by Sclerotinia minor. Latin type lettuce cultivars are small plants with upright leaves longer than they are wide, similar to romaine type...

  18. Interactions of Bacillus spp. and plants--with special reference to induced systemic resistance (ISR).

    Science.gov (United States)

    Choudhary, Devendra K; Johri, Bhavdish N

    2009-01-01

    Biological control of soil-borne pathogens comprises the decrease of inoculum or of the disease producing activity of a pathogen through one or more mechanisms. Interest in biological control of soil-borne plant pathogens has increased considerably in the last few decades, because it may provide control of diseases that cannot or only partly be managed by other control strategies. Recent advances in microbial and molecular techniques have significantly contributed to new insights in underlying mechanisms by which introduced bacteria function. Colonization of plant roots is an essential step for both soil-borne pathogenic and beneficial rhizobacteria. Colonization patterns showed that rhizobacteria act as biocontrol agents or as growth-promoting bacteria form microcolonies or biofilms at preferred sites of root exudation. Such microcolonies are sites for bacteria to communicate with each other (quorum sensing) and to act in a coordinated manner. Elicitation of induced systemic resistance (ISR) by plant-associated bacteria was initially demonstrated using Pseudomonas spp. and other Gram-negative bacteria. Several strains of the species Bacillus amyloliquefaciens, B. subtilis, B. pasteurii, B. cereus, B. pumilus, B. mycoides, and B. sphaericus elicit significant reductions in the incidence or severity of various diseases on a diversity of hosts. Elicitation of ISR by these strains has been demonstrated in greenhouse or field trials on tomato, bell pepper, muskmelon, watermelon, sugar beet, tobacco, Arabidopsis sp., cucumber, loblolly pine, and two tropical crops (long cayenne pepper and green kuang futsoi). Protection resulting from ISR elicited by Bacillus spp. has been reported against leaf-spotting fungal and bacterial pathogens, systemic viruses, a crown-rotting fungal pathogen, root-knot nematodes, and a stem-blight fungal pathogen as well as damping-off, blue mold, and late blight diseases. This progress will lead to a more efficient use of these strains which

  19. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants.

    Science.gov (United States)

    Silvestre, A; Cabaret, J

    2004-06-01

    In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control)? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation) are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole). Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy) are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial: it is not possible to avoid it, but only to delay its development in farm animal industry.

  20. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

    Directory of Open Access Journals (Sweden)

    Silvestre A.

    2004-06-01

    Full Text Available In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control ? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole. Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial : it is not possible to avoid it, but only to delay its development in farm animal industry.

  1. Pathogen filtration to control plant disease outbreak in greenhouse production

    Science.gov (United States)

    Jeon, Sangho; Krasnow, Charles; Bhalsod, Gemini; Granke, Leah; Harlan, Blair; Hausbeck, Mary; Zhang, Wei

    2016-04-01

    Previous research has been extensively focused on understanding the fate and transport of human microbial pathogens in soil and water environments. However, little is known about the transport of plant pathogens, although these pathogens are often found in irrigation waters and could cause severe crop damage and economical loss. Water mold pathogens including Phytophthora spp. and Pythium spp. are infective to a wide range of vegetable and floriculture crops, and they are primarily harbored in soils and disseminated through water flow. It is challenging to control these pathogens because they often quickly develop resistance to many fungicides. Therefore, this multi-scale study aimed to investigate physical removal of plant pathogens from water by filtration, thus reducing the pathogen exposure risks to crops. In column-scale experiments, we studied controlling factors on the transport and retention of Phytophthora capsici zoospores in saturated columns packed with iron oxide coated-sand and uncoated-sand under varying solution chemistry. Biflagellate zoospores were less retained than encysted zoospores, and lower solution pH and greater iron oxide content increased the retention of encysted zoospores. These results provided insights on environmental dispersal of Phytophthora zoospores in natural soils as well as on developing cost-effective engineered filtration systems for pathogen removal. Using small-scale greenhouse filtration systems, we further investigated the performance of varying filter media (i.e., granular sand, iron oxide coated ceramic porous media, and activated carbon) in mitigating disease outbreaks of Phytophthora and Pythium for greenhouse-grown squash and poinsettia, respectively, in comparison with fungicide treatment. For squash, filtration by iron oxide coated media was more effective in reducing the Phytophthora infection, comparing to sand filtration and fungicide application. For poinsettia, sand filtration performed better in controlling

  2. Medicinal Plants Targeting Cardiovascular Diseases in View of Avicenna.

    Science.gov (United States)

    Sobhani, Zahra; Nami, Saeed Reza; Emami, Seyed Ahmad; Sahebkar, Amirhossein; Javadi, Behjat

    2017-01-01

    Cardiovascular disease (CVD) is a spectrum of diseases involving the heart and blood vessels, and the first cause of mortality worldwide. Medicinal plants have been used for thousands of years to treat CVD. In Traditional Persian Medicine (TPM), there is a special focus on heart diseases. Avicenna, a Persian physician of the eleventh century compiled a book devoted to this field named "The treatise on cardiac drugs" which is a compendium of TPM knowledge on CVD. Avicenna mentioned 50 cardiovascular active plants and described their therapeutic effects in the treatment of CVDs. Here, we perform a detailed search in scientific databases to verify the cardiovascular activities of the medicinal plants suggested by Avicenna. Also, we discussed cardiovascular activities of a number of the most important suggested plants as well as their efficacy in clinical studies. Major bioactive compounds identified from these plants are also discussed. Pharmacological studies have revealed that the majority of these plants are effective in cardiovascular health with various mechanisms. Among them, Crocus sativus L., Cinnamomum cassia (L.) J. Presl, Punica granatum L., Ocimum basilicum L., Elettaria cardamomum (L.) Maton, Melissa officinalis L. and Phyllanthus emblica L. have proved to be more effective. The above-mentioned plants can be rich sources for developing new and effective pharmaceuticals for the treatment of CVDs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Phosphorylation of an ERF transcription factor by Arabidopsis MPK3/MPK6 regulates plant defense gene induction and fungal resistance.

    Science.gov (United States)

    Meng, Xiangzong; Xu, Juan; He, Yunxia; Yang, Kwang-Yeol; Mordorski, Breanne; Liu, Yidong; Zhang, Shuqun

    2013-03-01

    Arabidopsis thaliana MPK3 and MPK6, two mitogen-activated protein kinases (MAPKs or MPKs), play critical roles in plant disease resistance by regulating multiple defense responses. Previously, we characterized the regulation of phytoalexin biosynthesis by Arabidopsis MPK3/MPK6 cascade and its downstream WRKY33 transcription factor. Here, we report another substrate of MPK3/MPK6, ETHYLENE RESPONSE FACTOR6 (ERF6), in regulating Arabidopsis defense gene expression and resistance to the necrotrophic fungal pathogen Botrytis cinerea. Phosphorylation of ERF6 by MPK3/MPK6 in either the gain-of-function transgenic plants or in response to B. cinerea infection increases ERF6 protein stability in vivo. Phospho-mimicking ERF6 is able to constitutively activate defense-related genes, especially those related to fungal resistance, including PDF1.1 and PDF1.2, and confers enhanced resistance to B. cinerea. By contrast, expression of ERF6-EAR, in which ERF6 was fused to the ERF-associated amphiphilic repression (EAR) motif, strongly suppresses B. cinerea-induced defense gene expression, leading to hypersusceptibility of the ERF6-EAR transgenic plants to B. cinerea. Different from ERF1, the regulation and function of ERF6 in defensin gene activation is independent of ethylene. Based on these data, we conclude that ERF6, another substrate of MPK3 and MPK6, plays important roles downstream of the MPK3/MPK6 cascade in regulating plant defense against fungal pathogens.

  4. Soybean (Glycine max L. Merr. sprouts germinated under red light irradiation induce disease resistance against bacterial rotting disease.

    Directory of Open Access Journals (Sweden)

    Radhika Dhakal

    Full Text Available Specific wavelengths of light can exert various physiological changes in plants, including effects on responses to disease incidence. To determine whether specific light wavelength had effects on rotting disease caused by Pseudomonas putida 229, soybean sprouts were germinated under a narrow range of wavelengths from light emitting diodes (LEDs, including red (650-660, far red (720-730 and blue (440-450 nm or broad range of wavelength from daylight fluorescence bulbs. The controls were composed of soybean sprouts germinated in darkness. After germination under different conditions for 5 days, the soybean sprouts were inoculated with P. putida 229 and the disease incidence was observed for 5 days. The sprouts exposed to red light showed increased resistance against P. putida 229 relative to those grown under other conditions. Soybean sprouts germinated under red light accumulated high levels of salicylic acid (SA accompanied with up-regulation of the biosynthetic gene ICS and the pathogenesis- related (PR gene PR-1, indicating that the resistance was induced by the action of SA via de novo synthesis of SA in the soybean sprouts by red light irradiation. Taken together, these data suggest that only the narrow range of red light can induce disease resistance in soybean sprouts, regulated by the SA-dependent pathway via the de novo synthesis of SA and up-regulation of PR genes.

  5. Soybean (Glycine max L. Merr.) sprouts germinated under red light irradiation induce disease resistance against bacterial rotting disease.

    Science.gov (United States)

    Dhakal, Radhika; Park, Euiho; Lee, Se-Weon; Baek, Kwang-Hyun

    2015-01-01

    Specific wavelengths of light can exert various physiological changes in plants, including effects on responses to disease incidence. To determine whether specific light wavelength had effects on rotting disease caused by Pseudomonas putida 229, soybean sprouts were germinated under a narrow range of wavelengths from light emitting diodes (LEDs), including red (650-660), far red (720-730) and blue (440-450 nm) or broad range of wavelength from daylight fluorescence bulbs. The controls were composed of soybean sprouts germinated in darkness. After germination under different conditions for 5 days, the soybean sprouts were inoculated with P. putida 229 and the disease incidence was observed for 5 days. The sprouts exposed to red light showed increased resistance against P. putida 229 relative to those grown under other conditions. Soybean sprouts germinated under red light accumulated high levels of salicylic acid (SA) accompanied with up-regulation of the biosynthetic gene ICS and the pathogenesis- related (PR) gene PR-1, indicating that the resistance was induced by the action of SA via de novo synthesis of SA in the soybean sprouts by red light irradiation. Taken together, these data suggest that only the narrow range of red light can induce disease resistance in soybean sprouts, regulated by the SA-dependent pathway via the de novo synthesis of SA and up-regulation of PR genes.

  6. Systemic resistance induced by Bacillus lipopeptides in Beta vulgaris reduces infection by the rhizomania disease vector Polymyxa betae.

    Science.gov (United States)

    Desoignies, Nicolas; Schramme, Florence; Ongena, Marc; Legrève, Anne

    2013-05-01

    The control of rhizomania, one of the most important diseases of sugar beet caused by the Beet necrotic yellow vein virus, remains limited to varietal resistance. In this study, we investigated the putative action of Bacillus amylolequifaciens lipopeptides in achieving rhizomania biocontrol through the control of the virus vector Polymyxa betae. Some lipopeptides that are produced by bacteria, especially by plant growth-promoting rhizobacteria, have been found to induce systemic resistance in plants. We tested the impact of the elicitation of systemic resistance in sugar beet through lipopeptides on infection by P. betae. Lipopeptides were shown to effectively induce systemic resistance in both the roots and leaves of sugar beet, resulting in a significant reduction in P. betae infection. This article provides the first evidence that induced systemic resistance can reduce infection of sugar beet by P. betae.

  7. De Novo Transcriptome Sequencing of Oryza officinalis Wall ex Watt to Identify Disease-Resistance Genes

    Directory of Open Access Journals (Sweden)

    Bin He

    2015-12-01

    Full Text Available Oryza officinalis Wall ex Watt is one of the most important wild relatives of cultivated rice and exhibits high resistance to many diseases. It has been used as a source of genes for introgression into cultivated rice. However, there are limited genomic resources and little genetic information publicly reported for this species. To better understand the pathways and factors involved in disease resistance and accelerating the process of rice breeding, we carried out a de novo transcriptome sequencing of O. officinalis. In this research, 137,229 contigs were obtained ranging from 200 to 19,214 bp with an N50 of 2331 bp through de novo assembly of leaves, stems and roots in O. officinalis using an Illumina HiSeq 2000 platform. Based on sequence similarity searches against a non-redundant protein database, a total of 88,249 contigs were annotated with gene descriptions and 75,589 transcripts were further assigned to GO terms. Candidate genes for plant–pathogen interaction and plant hormones regulation pathways involved in disease-resistance were identified. Further analyses of gene expression profiles showed that the majority of genes related to disease resistance were all expressed in the three tissues. In addition, there are two kinds of rice bacterial blight-resistant genes in O. officinalis, including two Xa1 genes and three Xa26 genes. All 2 Xa1 genes showed the highest expression level in stem, whereas one of Xa26 was expressed dominantly in leaf and other 2 Xa26 genes displayed low expression level in all three tissues. This transcriptomic database provides an opportunity for identifying the genes involved in disease-resistance and will provide a basis for studying functional genomics of O. officinalis and genetic improvement of cultivated rice in the future.

  8. Tomato plants ectopically expressing Arabidopsis CBF1 show enhanced resistance to water deficit stress.

    Science.gov (United States)

    Hsieh, Tsai-Hung; Lee, Jent-turn; Charng, Yee-yung; Chan, Ming-Tsair

    2002-10-01

    A DNA cassette containing an Arabidopsis C repeat/dehydration-responsive element binding factor 1 (CBF1) cDNA and a nos terminator, driven by a cauliflower mosaic virus 35S promoter, was transformed into the tomato (Lycopersicon esculentum) genome. These transgenic tomato plants were more resistant to water deficit stress than the wild-type plants. The transgenic plants exhibited growth retardation by showing dwarf phenotype, and the fruit and seed numbers and fresh weight of the transgenic tomato plants were apparently less than those of the wild-type plants. Exogenous gibberellic acid treatment reversed the growth retardation and enhanced growth of transgenic tomato plants, but did not affect the level of water deficit resistance. The stomata of the transgenic CBF1 tomato plants closed more rapidly than the wild type after water deficit treatment with or without gibberellic acid pretreatment. The transgenic tomato plants contained higher levels of Pro than those of the wild-type plants under normal or water deficit conditions. Subtractive hybridization was used to isolate the responsive genes to heterologous CBF1 in transgenic tomato plants and the CAT1 (CATALASE1) was characterized. Catalase activity increased, and hydrogen peroxide concentration decreased in transgenic tomato plants compared with the wild-type plants with or without water deficit stress. These results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants.

  9. Insulin resistance and gray matter volume in neurodegenerative disease.

    Science.gov (United States)

    Morris, J K; Vidoni, E D; Perea, R D; Rada, R; Johnson, D K; Lyons, K; Pahwa, R; Burns, J M; Honea, R A

    2014-06-13

    The goal of this study was to compare insulin resistance in aging and aging-related neurodegenerative diseases, and to determine the relationship between insulin resistance and gray matter volume (GMV) in each cohort using an unbiased, voxel-based approach. Insulin resistance was estimated in apparently healthy elderly control (HC, n=21) and neurodegenerative disease (Alzheimer's disease (AD), n=20; Parkinson's disease (PD), n=22) groups using Homeostasis Model Assessment of Insulin Resistance 2 (HOMA2) and intravenous glucose tolerance test (IVGTT). HOMA2 and GMV were assessed within groups through General Linear Model multiple regression. We found that HOMA2 was increased in both AD and PD compared to the HC group (HC vs. AD, p=0.002, HC vs. PD, p=0.003), although only AD subjects exhibited increased fasting glucose (p=0.005). Furthermore, our voxel-based morphometry analysis revealed that HOMA2 was related to GMV in all cohorts in a region-specific manner (p<0.001, uncorrected). Significant relationships were observed in the medial prefrontal cortex (HC), medial temporal regions (AD), and parietal regions (PD). Finally, the directionality of the relationship between HOMA2 and GMV was disease-specific. Both HC and AD subjects exhibited negative relationships between HOMA2 and brain volume (increased HOMA2 associated with decreased brain volume), while a positive relationship was observed in PD. This cross-sectional study suggests that insulin resistance is increased in neurodegenerative disease, and that individuals with AD appear to have more severe metabolic dysfunction than individuals with PD or PD dementia.

  10. Importância, problemas e perspectivas do melhoramento visando resistência a viroses em plantas Importance, problems and perspectives of plant breeding concerning resistance to viruses

    Directory of Open Access Journals (Sweden)

    Rosa Lia Barbieri

    1995-01-01

    Full Text Available As viroses são um sério problema para a agricultura, podendo se tomar um fator limitante para o desenvolvimento de determinadas espécies. Medidas de controle, como a eliminação dos vetores, o uso de material sadio, a rotação de culturas e a erradicação de plantas infectadas são apenas soluções temporárias. A mais eficiente estratégia de controle envolve o uso de cultivares melhoradas para resistência ao vírus ou a seu vetor. A reduzida disponibilidade de fontes de resistência pode ser aumentada através da tecnologia do DNA recombinante, que traz novas perspectivas para o melhoramento de plantas resistentes a viroses.Virus diseases are a serious problem to agricuiture, can be a limitant factor to normal development of some crops. Control measures, like vectors elimination, healthy material use, culture rotation and infected plants eradication, are only transient solutions. The more efficient approach for control involves plant breeding resistant to virus or its vector. Reduced availability of resistance source can be increased through recombinant DNA technology, which brings new breeding perspectives to virus resistant crops.

  11. Field Trial and Molecular Characterization of RNAi-Transgenic Tomato Plants That Exhibit Resistance to Tomato Yellow Leaf Curl Geminivirus.

    Science.gov (United States)

    Fuentes, Alejandro; Carlos, Natacha; Ruiz, Yoslaine; Callard, Danay; Sánchez, Yadira; Ochagavía, María Elena; Seguin, Jonathan; Malpica-López, Nachelli; Hohn, Thomas; Lecca, Maria Rita; Pérez, Rosabel; Doreste, Vivian; Rehrauer, Hubert; Farinelli, Laurent; Pujol, Merardo; Pooggin, Mikhail M

    2016-03-01

    RNA interference (RNAi) is a widely used approach to generate virus-resistant transgenic crops. However, issues of agricultural importance like the long-term durability of RNAi-mediated resistance under field conditions and the potential side effects provoked in the plant by the stable RNAi expression remain poorly investigated. Here, we performed field trials and molecular characterization studies of two homozygous transgenic tomato lines, with different selection markers, expressing an intron-hairpin RNA cognate to the Tomato yellow leaf curl virus (TYLCV) C1 gene. The tested F6 and F4 progenies of the respective kanamycin- and basta-resistant plants exhibited unchanged field resistance to TYLCV and stably expressed the transgene-derived short interfering RNA (siRNAs) to represent 6 to 8% of the total plant small RNAs. This value outnumbered the average percentage of viral siRNAs in the nontransformed plants exposed to TYLCV-infested whiteflies. As a result of the RNAi transgene expression, a common set of up- and downregulated genes was revealed in the transcriptome profile of the plants selected from either of the two transgenic events. A previously unidentified geminivirus causing no symptoms of viral disease was detected in some of the transgenic plants. The novel virus acquired V1 and V2 genes from TYLCV and C1, C2, C3, and C4 genes from a distantly related geminivirus and, thereby, it could evade the repressive sequence-specific action of transgene-derived siRNAs. Our findings shed light on the mechanisms of siRNA-directed antiviral silencing in transgenic plants and highlight the applicability limitations of this technology as it may alter the transcriptional pattern of nontarget genes.

  12. Identification of Adenyl Cyclase Activity in a Disease Resistance Protein in Arabidopsis thaliana

    KAUST Repository

    Hussein, Rana

    2012-11-01

    Cyclic nucleotide, cAMP, is an important signaling molecule in animals and plants. However, in plants the enzymes that synthesize this second messenger, adenyl cyclases (ACs), remain elusive. Given the physiological importance of cAMP in signaling, particularly in response to biotic and abiotic stresses, it is thus important to identify and characterize ACs in higher plants. Using computational approaches, a disease resistance protein from Arabidopsis thaliana, At3g04220 was found to have an AC catalytic center motif. In an attempt to prove that this candidate has adenyl cyclases activity in vitro, the coding sequence of the putative AC catalytic domain of this protein was cloned and expressed in E. coli and the recombinant protein was purified. The nucleotide cyclase activity of the recombinant protein was examined using cyclic nucleotide enzyme immunoassays. In parallel, the expression of At3g04220 was measured in leaves under three different stress conditions in order to determine under which conditions the disease resistance protein could function. Results show that the purified recombinant protein has Mn2+ dependent AC activity in vitro, and the expression analysis supports a role for At3g04220 and cAMP in plant defense.

  13. Planting and care of fine hardwood seedlings: diseases in hardwood tree plantings

    Science.gov (United States)

    Paula M. Pijut

    2006-01-01

    Hardwood trees planted for timber production, wildlife habitat, riparian buffers, native woodland restoration, windbreaks, watershed protection, erosion control, and conservation are susceptible to damage or even death by various native and exotic fungal or bacterial diseases. Establishment, growth, and the quality of the trees produced can be affected by these disease...

  14. Insulin resistance: an emerging link in Alzheimer's disease.

    Science.gov (United States)

    Medhi, Bikash; Chakrabarty, Mrinmoy

    2013-10-01

    Relentless progression of Alzheimer's disease (AD) poses a grave situation for the biomedical community to tackle. Agents starting as hot favorites in clinical trials have failed in later stages and it is time we reconsidered our approaches to intervene the disease. Quite some interesting work in the last decade has introduced a new school of thought which factors in neuronal glycemic imbalance as a major component for the development of AD. Insulin resistance in the brain has brought forward subsequent sequelae which might work towards amyloid accretion and/or tau hyperphosphorylation. It is also pointed out that insulin works by distributing iron to neuronal tissue and an insulin resistant state throws it off gear leading to iron overloading of neurons which is ultimately detrimental. A relatively recent investigation finds the role of c-Jun-N-terminal kinase (JNK3) in AD which also seems to bear a link with insulin resistance.

  15. Resistant Kawasaki disease, case report and literatures review

    Directory of Open Access Journals (Sweden)

    M.J. Saffar

    2006-01-01

    Full Text Available A child with aggressive and resistant Kawasaki disease with coronary aneurysm is described. Despite two doses of immune globulin and high dose of aspirin the patient was treated with the third dose of immune globulin. The patient apparently responded to normalization of symptoms and signs, with no more progression of coronary artery abnormalities.

  16. Quantitative disease resistance: dissection and adoption in maize

    Science.gov (United States)

    Maize is the world’s most widely cultivated crop, providing food, feed, and biofuel. Maize production is constantly threatened by the presence of devastating pathogens worldwide. Characterization of the genetic components underlying disease resistance is a major research area in maize which is highl...

  17. Evaluating paradox walnut rootstocks for resistance to Armillaria root disease

    Science.gov (United States)

    The most common Juglans regia (English walnut) rootstock in California is Paradox, a hybrid between J. hindsii (Northern California black walnut) and J. regia. Unfortuntely, Paradox rootstock is highly susceptible to Armillaria root disease. The relative resistance of new clonal, Paradox rootstock...

  18. Identification of blast resistance genes for managing rice blast disease

    Science.gov (United States)

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating diseases worldwide. In the present study, an international set of monogenic differentials carrying 24 major blast resistance (R) genes (Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit, Pita, Pita2,...

  19. The Italian elm breeding program for Dutch elm disease resistance

    Science.gov (United States)

    Alberto Santini; Francesco Pecori; Luisa Ghelardini

    2012-01-01

    In the 20th century, elms across Europe and North America were devastated by two pandemics of Dutch elm disease (DED), caused by the introduction of two fungal pathogens: Ophiostoma ulmi, followed by O. novo-ulmi. At the end of 1920s, research into a resistance to DED began in Europe and then in the United States. No...

  20. Enhancement of induced disease resistance by simultaneous activation of salicylate- and jasmonate-dependent defense pathways in Arabidopsis thaliana

    NARCIS (Netherlands)

    Wees, A.C.M. van; Swart, E.A.M. de; Pelt, J.A. van; Loon, L.C. van; Pieterse, C.M.J.

    2000-01-01

    The plant-signaling molecules salicylic acid (SA) and jasmonic acid (JA) play an important role in induced disease resistance pathways. Cross-talk between SA- and JA-dependent pathways can result in inhibition of JA-mediated defense responses. We investigated possible antagonistic interactions betwe

  1. Genetic and physical analysis of a YAC contig spanning the fungal disease resistance locus Asc of tomato (Lycopersicon esculentum)

    NARCIS (Netherlands)

    Mesbah, L.A.; Kneppers, T.J.A.; Takken, F.L.W.; Laurent, P.; Hille, J.; Nijkamp, H.J.J.

    1998-01-01

    The Alternaria stem canker disease of tomato is caused by the necrotrophic fungal pathogen Alternaria alternata f. sp. lycopersici (AAL). The fungus produces AAL toxins that kill the plant tissue. Resistance to the fungus segregates as a single locus, called Asc, and has been genetically mapped on c

  2. Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a glutathione S-transferase gene

    Science.gov (United States)

    Plants are attacked by pathogens representing diverse taxonomic groups, such that genes providing multiple disease resistance (MDR) would likely be under positive selection pressure. We examined the novel proposition that naturally occurring allelic variants may confer MDR. To do so, we applied a ...

  3. Why is antibiotic resistance a deadly emerging disease?

    Science.gov (United States)

    Courvalin, P

    2016-05-01

    Evolution of bacteria towards resistance to antimicrobial agents, including multidrug resistance, is unavoidable because it represents a particular aspect of the general evolution of bacteria that is unstoppable. Therefore, the only means of dealing with this situation is to delay the emergence and subsequent dissemination of resistant bacteria or resistance genes. In this review, we will consider the biochemical mechanisms and the genetics that bacteria use to offset antibiotic selective pressure. The data provided are mainly, if not exclusively, taken from the work carried out in the laboratory, although there are numerous other examples in the literature. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  4. Probiotic Diversity Enhances Rhizosphere Microbiome Function and Plant Disease Suppression

    OpenAIRE

    Hu, Jie; Wei, Zhong; Friman, Ville Petri; Gu, Shao-Hua; Wang, Xiao-Fang; Eisenhauer, Nico; Yang, Tian-jie; Ma, Jing; Shen, Qi-Rong; Xu, Yang-chun; Jousset, Alexandre

    2016-01-01

    Bacterial communities associated with plant roots play an important role in the suppression of soil-borne pathogens, and multispecies probiotic consortia may enhance disease suppression efficacy. Here we introduced defined Pseudomonas species consortia into naturally complex microbial communities and measured the importance of Pseudomonas community diversity for their survival and the suppression of the bacterial plant pathogen Ralstonia solanacearum in the tomato rhizosphere microbiome. The ...

  5. Genome-Wide Architecture of Disease Resistance Genes in Lettuce.

    Science.gov (United States)

    Christopoulou, Marilena; Wo, Sebastian Reyes-Chin; Kozik, Alex; McHale, Leah K; Truco, Maria-Jose; Wroblewski, Tadeusz; Michelmore, Richard W

    2015-10-08

    Genome-wide motif searches identified 1134 genes in the lettuce reference genome of cv. Salinas that are potentially involved in pathogen recognition, of which 385 were predicted to encode nucleotide binding-leucine rich repeat receptor (NLR) proteins. Using a maximum-likelihood approach, we grouped the NLRs into 25 multigene families and 17 singletons. Forty-one percent of these NLR-encoding genes belong to three families, the largest being RGC16 with 62 genes in cv. Salinas. The majority of NLR-encoding genes are located in five major resistance clusters (MRCs) on chromosomes 1, 2, 3, 4, and 8 and cosegregate with multiple disease resistance phenotypes. Most MRCs contain primarily members of a single NLR gene family but a few are more complex. MRC2 spans 73 Mb and contains 61 NLRs of six different gene families that cosegregate with nine disease resistance phenotypes. MRC3, which is 25 Mb, contains 22 RGC21 genes and colocates with Dm13. A library of 33 transgenic RNA interference tester stocks was generated for functional analysis of NLR-encoding genes that cosegregated with disease resistance phenotypes in each of the MRCs. Members of four NLR-encoding families, RGC1, RGC2, RGC21, and RGC12 were shown to be required for 16 disease resistance phenotypes in lettuce. The general composition of MRCs is conserved across different genotypes; however, the specific repertoire of NLR-encoding genes varied particularly of the rapidly evolving Type I genes. These tester stocks are valuable resources for future analyses of additional resistance phenotypes. Copyright © 2015 Christopoulou et al.

  6. Plant-Derived Natural Products for Parkinson's Disease Therapy.

    Science.gov (United States)

    Sengupta, T; Vinayagam, J; Singh, R; Jaisankar, P; Mohanakumar, K P

    2016-01-01

    Plant-derived natural products have made their own niche in the treatment of neurological diseases since time immemorial. Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, has no cure and the treatment available currently is symptomatic. This chapter thoughtfully and objectively assesses the scientific basis that supports the increasing use of these plant-derived natural products for the treatment of this chronic and progressive disorder. Proper considerations are made on the chemical nature, sources, preclinical tests and their validity, and mechanisms of behavioural or biochemical recovery observed following treatment with various plants derived natural products relevant to PD therapy. The scientific basis underlying the neuroprotective effect of 6 Ayurvedic herbs/formulations, 12 Chinese medicinal herbs/formulations, 33 other plants, and 5 plant-derived molecules have been judiciously examined emphasizing behavioral, cellular, or biochemical aspects of neuroprotection observed in the cellular or animal models of the disease. The molecular mechanisms triggered by these natural products to promote cell survivability and to reduce the risk of cellular degeneration have also been brought to light in this study. The study helped to reveal certain limitations in the scenario: lack of preclinical studies in all cases barring two; heavy dependence on in vitro test systems; singular animal or cellular model to establish any therapeutic potential of drugs. This strongly warrants further studies so as to reproduce and confirm these reported effects. However, the current literature offers scientific credence to traditionally used plant-derived natural products for the treatment of PD.

  7. 植物天然免疫性研究进展及其对作物抗病育种的可能影响%Recent Findings in Plant Innate Immunity and Possible Impacts on Crop Disease-resistance Breeding

    Institute of Scientific and Technical Information of China (English)

    赵开军; 李岩强; 王春连; 高英

    2011-01-01

    , natural selection has been driving pathogens to avoid ETI either by diversifying the recognized effectors or by acquiring additional effectors that suppress ETI.On the other hand, natural selection favors plant new R-genes that can recognize the newly acquired effectors in pathogen, resulting in new ETI to be triggered again.The latest studies have revealed the simple cipher that governs DNA recognition by TAL (transcription activator-like) effectors from plant pathogenic Xanthomonas.TAL effectors can specifically bind the target DNA of host plant with a novel protein-DNA binding pattern in which two amino acids recognize one nucleotide.Using this recognition code, TAL effectors can bind the promoter of target genes and induce the host diseases or resistance responses.Recent findings about plant innate immunity are reviewed in this paper and their possible applications in plant breeding for disease resistance are discussed.

  8. Plant defense against herbivorous pests: exploiting resistance and tolerance traits for sustainable crop protection

    Directory of Open Access Journals (Sweden)

    Carolyn Mitchell

    2016-07-01

    Full Text Available Interactions between plants and insect herbivores are important determinants of plant productivity in managed and natural vegetation. In response to attack, plants have evolved a range of defenses to reduce the threat of injury and loss of productivity. Crop losses from damage caused by arthropod pests can exceed 15% annually. Crop domestication and selection for improved yield and quality can alter the defensive capability of the crop, increasing reliance on artificial crop protection. Sustainable agriculture, however, depends on reduced chemical inputs. There is an urgent need, therefore, to identify plant defensive traits for crop improvement. Plant defense can be divided into resistance and tolerance strategies. Plant traits that confer herbivore resistance typically prevent or reduce herbivore damage through expression of traits that deter pests from settling, attaching to surfaces, feeding and reproducing, or that reduce palatability. Plant tolerance of herbivory involves expression of traits that limit the negative impact of herbivore damage on productivity and yield. Identifying the defensive traits expressed by plants to deter herbivores or limit herbivore damage, and understanding the underlying defense mechanisms, is crucial for crop scientists to exploit plant defensive traits in crop breeding. In this review, we assess the traits and mechanisms underpinning herbivore resistance and tolerance, and conclude that physical defense traits, plant vigor and herbivore-induced plant volatiles show considerable utility in pest control, along with mixed species crops. We highlight emerging approaches for accelerating the identification of plant defensive traits and facilitating their deployment to improve the future sustainability of crop protection.

  9. Plant Defense against Herbivorous Pests: Exploiting Resistance and Tolerance Traits for Sustainable Crop Protection.

    Science.gov (United States)

    Mitchell, Carolyn; Brennan, Rex M; Graham, Julie; Karley, Alison J

    2016-01-01

    Interactions between plants and insect herbivores are important determinants of plant productivity in managed and natural vegetation. In response to attack, plants have evolved a range of defenses to reduce the threat of injury and loss of productivity. Crop losses from damage caused by arthropod pests can exceed 15% annually. Crop domestication and selection for improved yield and quality can alter the defensive capability of the crop, increasing reliance on artificial crop protection. Sustainable agriculture, however, depends on reduced chemical inputs. There is an urgent need, therefore, to identify plant defensive traits for crop improvement. Plant defense can be divided into resistance and tolerance strategies. Plant traits that confer herbivore resistance typically prevent or reduce herbivore damage through expression of traits that deter pests from settling, attaching to surfaces, feeding and reproducing, or that reduce palatability. Plant tolerance of herbivory involves expression of traits that limit the negative impact of herbivore damage on productivity and yield. Identifying the defensive traits expressed by plants to deter herbivores or limit herbivore damage, and understanding the underlying defense mechanisms, is crucial for crop scientists to exploit plant defensive traits in crop breeding. In this review, we assess the traits and mechanisms underpinning herbivore resistance and tolerance, and conclude that physical defense traits, plant vigor and herbivore-induced plant volatiles show considerable utility in pest control, along with mixed species crops. We highlight emerging approaches for accelerating the identification of plant defensive traits and facilitating their deployment to improve the future sustainability of crop protection.

  10. Host-plant-mediated effects of Nadefensin on herbivore and pathogen resistance in Nicotiana attenuata

    Directory of Open Access Journals (Sweden)

    Baldwin Ian T

    2008-10-01

    Full Text Available Abstract Background The adage from Shakespeare, "troubles, not as single spies, but in battalions come," holds true for Nicotiana attenuata, which is commonly attacked by both pathogens (Pseudomonas spp. and herbivores (Manduca sexta in its native habitats. Defense responses targeted against the pathogens can directly or indirectly influence the responses against the herbivores. Nadefensin is an effective induced defense gene against the bacterial pathogen Pseudomonas syringae pv tomato (PST DC3000, which is also elicited by attack from M. sexta larvae, but whether this defense protein influences M. sexta's growth and whether M. sexta-induced Nadefensin directly or indirectly influences PST DC3000 resistance are unknown. Results M. sexta larvae consumed less on WT and on Nadefensin-silenced N. attenuata plants that had previously been infected with PST DC3000 than on uninfected plants. WT plants infected with PST DC3000 showed enhanced resistance to PST DC3000 and decreased leaf consumption by M. sexta larvae, but larval mass gain was unaffected. PST DC3000-infected Nadefensin-silenced plants were less resistant to subsequent PST DC3000 challenge, and on these plants, M. sexta larvae consumed less and gained less mass. WT and Nadefensin-silenced plants previously damaged by M. sexta larvae were better able to resist subsequent PST DC3000 challenges than were undamaged plants. Conclusion These results demonstrate that Na-defensin directly mediates defense against PST DC3000 and indirectly against M. sexta in N. attenuata. In plants that were previously infected with PST DC3000, the altered leaf chemistry in PST DC3000-resistant WT plants and PST DC3000-susceptible Nadefensin-silenced plants differentially reduced M. sexta's leaf consumption and mass gain. In plants that were previously damaged by M. sexta, the combined effect of the altered host plant chemistry and a broad spectrum of anti-herbivore induced metabolomic responses was more

  11. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance

    OpenAIRE

    Manosalva, P; Manohar, M; von Reuss, S.; Chen, S.; Koch, A; Kaplan, F; Choe, A.; Micikas, R.; X. Wang; Kogel, K.; Sternberg, P.; Williamson, V; Schroeder, D; Klessig, F.

    2015-01-01

    Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentratio...

  12. Effect of biodiversity changes in disease risk: exploring disease emergence in a plant-virus system.

    Directory of Open Access Journals (Sweden)

    Israel Pagán

    Full Text Available The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect, and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect. Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species.

  13. Effect of biodiversity changes in disease risk: exploring disease emergence in a plant-virus system.

    Science.gov (United States)

    Pagán, Israel; González-Jara, Pablo; Moreno-Letelier, Alejandra; Rodelo-Urrego, Manuel; Fraile, Aurora; Piñero, Daniel; García-Arenal, Fernando

    2012-01-01

    The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species.

  14. Characterization and selection of location for resistance to sugarcane brown rust disease under cuban conditions

    Directory of Open Access Journals (Sweden)

    Joaquín Montalván Delgado

    2016-01-01

    Full Text Available The sugarcane brown rust disease is caused by fungus Puccinia melanocephala Sydow & P. Sydow and it is one of the more importance diseases. The environment where the sugarcane is cultivated is constituted by numerous factors and its combination contributes to the formation of different development and production conditions, what influences in the varietal disease resistance. With the objective of to characterize and to define the resistance tests location to the brown rust disease were carried out experiments in 6 location of the country. Eleven varieties and six patterns were studied. The climatic variables were analyzed during the period in each location and they were carried out evaluations in different ages of the plant and number of the leaves. The quantity of pustules, long of the most frequent pustules, size of the biggest pustules and area per - centage occupied by pustules were evaluated. The data were analyzed statistically. Differential behavior of the locations and the importance of the relative humidity and the temperatures in the manifestation of the disease symptoms were proven. All the locations were important although similarity exists between Matanzas and Villa Clara and between Camagüey and Holguín. Mayabeque and Santiago de Cuba didn’t present similarity with any other one. These 6 locations can be used for the resistance tests and to define the progenitors’ Santiago de Cuba, Holguín, Villa Clara and Mayabeque

  15. The impact of transition metals on bacterial plant disease.

    Science.gov (United States)

    Fones, Helen; Preston, Gail M

    2013-07-01

    Metals play essential roles in many biological processes but are toxic when present in excess. This makes their transport and homoeostatic control of particular importance to living organisms. Within the context of plant-pathogen interactions the availability and toxicity of transition metals can have a substantial impact on disease development. Metals are essential for defensive generation of reactive oxygen species and other plant defences and can be used directly to limit pathogen growth. Metal-based antimicrobials are used in agriculture to control plant disease, and there is increasing evidence that metal hyperaccumulating plants use accumulated metal to limit pathogen growth. Pathogens and hosts compete for available metals, with plants possessing mechanisms to withhold essential metals from invading microbes. Pathogens, meanwhile, use low-metal conditions as a signal to recognise and respond to the host environment. Consequently, metal-sensing systems such as fur (iron) and zur (zinc) regulate the expression of pathogenicity and virulence genes; and pathogens have developed sophisticated strategies to acquire metal during growth in plant tissues, including the production of multiple siderophores. This review explores the impact of transition metals on the processes that determine the outcome of bacterial infection in plants, with a particular emphasis on zinc, iron and copper. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  16. QTLs for Snow Mold Disease Resistance in Creeping Bentgrass

    Science.gov (United States)

    Snow molds caused by Typhula spp. are the most economically important winter diseases of turfgrass in the northern and alpine regions of the United States and Canada. During winter, the psychrophilic pathogens take advantage of the weakened host plants at low temperatures under persistent snow cover...

  17. The severity of wheat diseases increases when plants and pathogens are acclimatized to elevated carbon dioxide.

    Science.gov (United States)

    Váry, Zsolt; Mullins, Ewen; McElwain, Jennifer C; Doohan, Fiona M

    2015-04-20

    Wheat diseases present a constant and evolving threat to food security. We have little understanding as to how increased atmospheric carbon dioxide levels will affect wheat diseases and thus the security of grain supply. Atmospheric CO2 exceeded the 400 ppmv benchmark in 2013 and is predicted to double or even treble by the end of the century. This study investigated the impact of both pathogen and wheat acclimation to elevated CO2 on the development of Fusarium head blight (FHB) and Septoria tritici blotch (STB) disease of wheat. Here, plants and pathogens were cultivated under either 390 or 780 ppmv CO2 for a period (two wheat generations, multiple pathogen subcultures) prior to standard disease trials. Acclimation of pathogens and the wheat cultivar Remus to elevated CO2 increased the severity of both STB and FHB diseases, relative to ambient conditions. The effect of CO2 on disease development was greater for FHB than for STB. The highest FHB disease levels and associated yield losses were recorded for elevated CO2 -acclimated pathogen on elevated CO2 -acclimated wheat. When similar FHB experiments were conducted using the disease-resistant cultivar CM82036, pathogen acclimation significantly enhanced disease levels and yield loss under elevated CO2 conditions, thereby indicating a reduction in the effectiveness of the defence pathways innate to this wheat cultivar. We conclude that acclimation to elevated CO2 over the coming decades will have a significant influence on the outcome of plant-pathogen interactions and the durability of disease resistance. © 2015 John Wiley & Sons Ltd.

  18. Animal genomics and infectious disease resistance in poultry.

    Science.gov (United States)

    Smith, J; Gheyas, A; Burt, D W

    2016-04-01

    Avian pathogens are responsible for major costs to society, both in terms of huge economic losses to the poultry industry and their implications for human health. The health and welfare of millions of birds is under continued threat from many infectious diseases, some of which are increasing in virulence and thus becoming harder to control, such as Marek's disease virus and avian influenza viruses. The current era in animal genomics has seen huge developments in both technologies and resources, which means that researchers have never been in a better position to investigate the genetics of disease resistance and determine the underlying genes/mutations which make birds susceptible or resistant to infection. Avian genomics has reached a point where the biological mechanisms of infectious diseases can be investigated and understood in poultry and other avian species. Knowledge of genes conferring disease resistance can be used in selective breeding programmes or to develop vaccines which help to control the effects of these pathogens, which have such a major impact on birds and humans alike.

  19. Antibiotic resistance differentiates Echinacea purpurea endophytic bacterial communities with respect to plant organs.

    Science.gov (United States)

    Mengoni, Alessio; Maida, Isabel; Chiellini, Carolina; Emiliani, Giovanni; Mocali, Stefano; Fabiani, Arturo; Fondi, Marco; Firenzuoli, Fabio; Fani, Renato

    2014-10-01

    Recent findings have shown that antibiotic resistance is widespread in multiple environments and multicellular organisms, as plants, harboring rich and complex bacterial communities, could be hot spot for emergence of antibiotic resistances as a response to bioactive molecules production by members of the same community. Here, we investigated a panel of 137 bacterial isolates present in different organs of the medicinal plant Echinacea purpurea, aiming to evaluate if different plant organs harbor strains with different antibiotic resistance profiles, implying then the presence of different biological interactions in the communities inhabiting different plant organs. Data obtained showed a large antibiotic resistance variability among strains, which was strongly related to the different plant organs (26% of total variance, P < 0.0001). Interestingly this uneven antibiotic resistance pattern was present also when a single genus (Pseudomonas), ubiquitous in all organs, was analyzed and no correlation of antibiotic resistance pattern with genomic relatedness among strains was found. In conclusion, we speculate that antibiotic resistance patterns are tightly linked to the type of plant organ under investigation, suggesting the presence of differential forms of biological interaction in stem/leaves, roots and rhizosphere. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  20. Transgenic Brassica juncea plants expressing MsrA1, a synthetic cationic antimicrobial peptide, exhibit resistance to fungal phytopathogens.

    Science.gov (United States)

    Rustagi, Anjana; Kumar, Deepak; Shekhar, Shashi; Yusuf, Mohd Aslam; Misra, Santosh; Sarin, Neera Bhalla

    2014-06-01

    Cationic antimicrobial peptides (CAPs) have shown potential against broad spectrum of phytopathogens. Synthetic versions with desirable properties have been modeled on these natural peptides. MsrA1 is a synthetic chimera of cecropin A and melittin CAPs with antimicrobial properties. We generated transgenic Brassica juncea plants expressing the msrA1 gene aimed at conferring fungal resistance. Five independent transgenic lines were evaluated for resistance to Alternaria brassicae and Sclerotinia sclerotiorum, two of the most devastating pathogens of B. juncea crops. In vitro assays showed inhibition by MsrA1 of Alternaria hyphae growth by 44-62 %. As assessed by the number and size of lesions and time taken for complete leaf necrosis, the Alternaria infection was delayed and restricted in the transgenic plants with the protection varying from 69 to 85 % in different transgenic lines. In case of S. sclerotiorum infection, the lesions were more severe and spread profusely in untransformed control compared with transgenic plants. The sclerotia formed in the stem of untransformed control plants were significantly more in number and larger in size than those present in the transgenic plants where disease protection of 56-71.5 % was obtained. We discuss the potential of engineering broad spectrum biotic stress tolerance by transgenic expression of CAPs in crop plants.

  1. Comparisons of protein profiles of beech bark disease resistant and susceptible American beech (Fagus grandifolia

    Directory of Open Access Journals (Sweden)

    Mason Mary E

    2013-01-01

    Full Text Available Abstract Background Beech bark disease is an insect-fungus complex that damages and often kills American beech trees and has major ecological and economic impacts on forests of the northeastern United States and southeastern Canadian forests. The disease begins when exotic beech scale insects feed on the bark of trees, and is followed by infection of damaged bark tissues by one of the Neonectria species of fungi. Proteomic analysis was conducted of beech bark proteins from diseased trees and healthy trees in areas heavily infested with beech bark disease. All of the diseased trees had signs of Neonectria infection such as cankers or fruiting bodies. In previous tests reported elsewhere, all of the diseased trees were demonstrated to be susceptible to the scale insect and all of the healthy trees were demonstrated to be resistant to the scale insect. Sixteen trees were sampled from eight geographically isolated stands, the sample consisting of 10 healthy (scale-resistant and 6 diseased/infested (scale-susceptible trees. Results Proteins were extracted from each tree and analysed in triplicate by isoelectric focusing followed by denaturing gel electrophoresis. Gels were stained and protein spots identified and intensity quantified, then a statistical model was fit to identify significant differences between trees. A subset of BBD differential proteins were analysed by mass spectrometry and matched to known protein sequences for identification. Identified proteins had homology to stress, insect, and pathogen related proteins in other plant systems. Protein spots significantly different in diseased and healthy trees having no stand or disease-by-stand interaction effects were identified. Conclusions Further study of these proteins should help to understand processes critical to resistance to beech bark disease and to develop biomarkers for use in tree breeding programs and for the selection of resistant trees prior to or in early stages of BBD

  2. Transcriptional response of virus-infected cassava and identification of putative sources of resistance for cassava brown streak disease.

    Science.gov (United States)

    Maruthi, M N; Bouvaine, Sophie; Tufan, Hale A; Mohammed, Ibrahim U; Hillocks, Rory J

    2014-01-01

    Cassava (Manihot esculenta) is a major food staple in sub-Saharan Africa, which is severely affected by cassava brown streak disease (CBSD). The aim of this study was to identify resistance for CBSD as well as to understand the mechanism of putative resistance for providing effective control for the disease. Three cassava varieties; Kaleso, Kiroba and Albert were inoculated with cassava brown streak viruses by grafting and also using the natural insect vector the whitefly, Bemisia tabaci. Kaleso expressed mild or no disease symptoms and supported low concentrations of viruses, which is a characteristic of resistant plants. In comparison, Kiroba expressed severe leaf but milder root symptoms, while Albert was susceptible with severe symptoms both on leaves and roots. Real-time PCR was used to estimate virus concentrations in cassava varieties. Virus quantities were higher in Kiroba and Albert compared to Kaleso. The Illumina RNA-sequencing was used to further understand the genetic basis of resistance. More than 700 genes were uniquely overexpressed in Kaleso in response to virus infection compared to Albert. Surprisingly, none of them were similar to known resistant gene orthologs. Some of the overexpressed genes, however, belonged to the hormone signalling pathways and secondary metabolites, both of which are linked to plant resistance. These genes should be further characterised before confirming their role in resistance to CBSD.

  3. Transcriptional response of virus-infected cassava and identification of putative sources of resistance for cassava brown streak disease.

    Directory of Open Access Journals (Sweden)

    M N Maruthi

    Full Text Available Cassava (Manihot esculenta is a major food staple in sub-Saharan Africa, which is severely affected by cassava brown streak disease (CBSD. The aim of this study was to identify resistance for CBSD as well as to understand the mechanism of putative resistance for providing effective control for the disease. Three cassava varieties; Kaleso, Kiroba and Albert were inoculated with cassava brown streak viruses by grafting and also using the natural insect vector the whitefly, Bemisia tabaci. Kaleso expressed mild or no disease symptoms and supported low concentrations of viruses, which is a characteristic of resistant plants. In comparison, Kiroba expressed severe leaf but milder root symptoms, while Albert was susceptible with severe symptoms both on leaves and roots. Real-time PCR was used to estimate virus concentrations in cassava varieties. Virus quantities were higher in Kiroba and Albert compared to Kaleso. The Illumina RNA-sequencing was used to further understand the genetic basis of resistance. More than 700 genes were uniquely overexpressed in Kaleso in response to virus infection compared to Albert. Surprisingly, none of them were similar to known resistant gene orthologs. Some of the overexpressed genes, however, belonged to the hormone signalling pathways and secondary metabolites, both of which are linked to plant resistance. These genes should be further characterised before confirming their role in resistance to CBSD.

  4. P-Glycoprotein and Drug Resistance in Systemic Autoimmune Diseases

    Directory of Open Access Journals (Sweden)

    Andrea Picchianti-Diamanti

    2014-03-01

    Full Text Available Autoimmune diseases such as systemic lupus erythematosus (SLE, rheumatoid arthritis (RA and psoriatic arthritis (PsA are chronic inflammatory disorders of unknown etiology characterized by a wide range of abnormalities of the immune system that may compromise the function of several organs, such as kidney, heart, joints, brain and skin. Corticosteroids (CCS, synthetic and biologic immunosuppressive agents have demonstrated the capacity to improve the course of autoimmune diseases. However, a significant number of patients do not respond or develop resistance to these therapies over time. P-glycoprotein (P-gp is a transmembrane protein that pumps several drugs out of the cell, including CCS and immunosuppressants; thus, its over-expression or hyper-function has been proposed as a possible mechanism of drug resistance in patients with autoimmune disorders. Recently, different authors have demonstrated that P-gp inhibitors, such as cyclosporine A (CsA and its analogue Tacrolimus, are able to reduce P-gp expression and or function in SLE, RA and PsA patients. These observations suggest that P-gp antagonists could be adopted to revert drug resistance and improve disease outcome. The complex inter-relationship among drug resistance, P-gp expression and autoimmunity still remains elusive.

  5. A latitudinal cline in disease resistance of a host tree.

    Science.gov (United States)

    Hamilton, M G; Williams, D R; Tilyard, P A; Pinkard, E A; Wardlaw, T J; Glen, M; Vaillancourt, R E; Potts, B M

    2013-04-01

    The possible drivers and implications of an observed latitudinal cline in disease resistance of a host tree were examined. Mycosphaerella leaf disease (MLD) damage, caused by Teratosphaeria species, was assessed in five Eucalyptus globulus (Tasmanian blue gum) common garden trials containing open-pollinated progeny from 13 native-forest populations. Significant population and family within population variation in MLD resistance was detected, which was relatively stable across different combinations of trial sites, ages, seasons and epidemics. A distinct genetic-based latitudinal cline in MLD damage among host populations was evident. Two lines of evidence argue that the observed genetic-based latitudinal trend was the result of direct pathogen-imposed selection for MLD resistance. First, MLD damage was positively associated with temperature and negatively associated with a prediction of disease risk in the native environment of these populations; and, second, the quantitative inbreeding coefficient (QST) significantly exceeded neutral marker FST at the trial that exhibited the greatest MLD damage, suggesting that diversifying selection contributed to differentiation in MLD resistance among populations. This study highlights the potential for spatial variation in pathogen risk to drive adaptive differentiation across the geographic range of a foundation host tree species.

  6. The role of aluminum sensing and signaling in plant aluminum resistance

    Institute of Scientific and Technical Information of China (English)

    Jiping Liu; Miguel A. Piñeros; Leon V. Kochian

    2014-01-01

    As researchers have gained a better understanding in recent years into the physiological, molecular, and genetic basis of how plants deal with aluminum (Al) toxicity in acid soils prevalent in the tropics and sub-tropics, it has become clear that an important component of these responses is the triggering and regulation of cellular pathways and processes by Al. In this review of plant Al signaling, we begin by summarizing the understanding of physiological mechanisms of Al resis-tance, which first led researchers to realize that Al stress induces gene expression and modifies protein function during the activation of Al resistance responses. Subsequently, an overview of Al resistance genes and their function provides verification that Al induction of gene expression plays a major role in Al resistance in many plant species. More recent research into the mechanistic basis for Al-induced transcrip-tional activation of resistance genes has led to the identifica-tion of several transcription factors as wel as cis-elements in the promoters of Al resistance genes that play a role in greater Al-induced gene expression as wel as higher constitutive expression of resistance genes in some plant species. Final y, the post-transcriptional and translational regulation of Al resistance proteins is addressed, where recent research has shown that Al can both directly bind to and alter activity of certain organic acid transporters, and also influence Al resistance proteins indirectly, via protein phosphorylation.

  7. Mechanism of the plant cytochrome P450 for herbicide resistance: a modelling study.

    Science.gov (United States)

    Li, Qinfan; Fang, Yupeng; Li, Xiuxiu; Zhang, Hong; Liu, Mengmeng; Yang, Huibin; Kang, Zhuo; Li, Yan; Wang, Yonghua

    2013-12-01

    Plant cytochrome P450 is a key enzyme responsible for the herbicide resistance but the molecular basis of the mechanism is unclear. To understand this, four typical plant P450s and a widely resistant herbicide chlortoluron were analysed by carrying out homology modelling, molecular docking, molecular dynamics simulations and binding free energy analysis. Our results demonstrate that: (i) the putative hydrophobic residues located in the F-helix and polar residues in I-helix are critical in the herbicide resistance; (ii) the binding mode analysis and binding free energy calculation indicate that the distance between catalytic site of chlortoluron and heme of P450, as well as the binding affinity are key elements affecting the resistance for plants. In conclusion, this work provides a new insight into the interactions of plant P450s with herbicide from a molecular level, offering valuable information for the future design of novel effective herbicides which also escape from the P450 metabolism.

  8. Combinative effects of a bacterial type-III effector and a biocontrol bacterium on rice growth and disease resistance

    Indian Academy of Sciences (India)

    Haiying Ren; Ganyu Gu; Juying Long; Qian Yin; Tingquan Wu; Tao Song; Shujian Zhang; Zhiyi Chen; Hansong Dong

    2006-12-01

    Expression of HpaGXoo, a bacterial type-III effector, in transgenic plants induces disease resistance. Resistance also can be elicited by biocontrol bacteria. In both cases, plant growth is often promoted. Here we address whether biocontrol bacteria and HpaGXoo can act together to provide better results in crop improvement. We studied effects of Pseudomonas cepacia on the rice variety R109 and the hpaGXoo-expressing rice line HER1. Compared to R109, HER1 showed increased growth, grain yield, and defense responses toward diseases and salinity stress. Colonization of roots by P. cepacia caused 20% and 13% increase, in contrast to controls, in root growth of R109 and HER1. Growth of leaves and stems also increased in R109 but that of HER1 was inhibited. When P. cepacia colonization was subsequent to plant inoculation with Rhizoctonia solani, a pathogen that causes sheath blight, the disease was less severe than controls in both R109 and HER1; HER1, nevertheless, was more resistant, suggesting that P. cepacia and HpaGXoo cooperate in inducing disease resistance. Several genes that critically regulate growth and defense behaved differentially in HER1 and R109 while responding to P. cepacia. In R109 leaves, the OsARF1 gene, which regulates plant growth, was expressed in consistence with growth promotion by P. cepacia. Inversely, OsARF1 expression was coincident with inhibition in growth of HER1 leaves. In both plants, the expression of OsEXP1, which encodes an expansin protein involved in plant growth, was concomitant with growth promotion in leaves instead of roots, in response to P. cepacia. We also studied OsMAPK, a gene that encodes a mitogen-activated protein kinase and controls defense responses toward salinity and infection by pathogens in rice. In response to P. cepacia, an early expression of OsMAPK was coincident with R109 resistance to the disease, while HER1 expressed the gene similarly whether P. cepacia was present or not. Evidently, P. cepacia and GXoo

  9. Using transgenic plants and modified plant viruses for the development of treatments for human diseases.

    Science.gov (United States)

    Loh, Hwei-San; Green, Brian J; Yusibov, Vidadi

    2017-08-08

    Production of proteins in plants for human health applications has become an attractive strategy attributed by their potentials for low-cost production, increased safety due to the lack of human or animal pathogens, scalability and ability to produce complex proteins. A major milestone for plant-based protein production for use in human health was achieved when Protalix BioTherapeutics produced taliglucerase alfa (Elelyso(®)) in suspension cultures of a transgenic carrot cell line for the treatment of patients with Gaucher's disease, was approved by the USA Food and Drug Administration in 2012. In this review, we are highlighting various approaches for plant-based production of proteins and recent progress in the development of plant-made therapeutics and biologics for the prevention and treatment of human diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Putting plant resistance traits on the map: a test of the idea that plants are better defended at lower latitudes.

    Science.gov (United States)

    Moles, Angela T; Wallis, Ian R; Foley, William J; Warton, David I; Stegen, James C; Bisigato, Alejandro J; Cella-Pizarro, Lucrecia; Clark, Connie J; Cohen, Philippe S; Cornwell, William K; Edwards, Will; Ejrnaes, Rasmus; Gonzales-Ojeda, Therany; Graae, Bente J; Hay, Gregory; Lumbwe, Fainess C; Magaña-Rodríguez, Benjamín; Moore, Ben D; Peri, Pablo L; Poulsen, John R; Veldtman, Ruan; von Zeipel, Hugo; Andrew, Nigel R; Boulter, Sarah L; Borer, Elizabeth T; Campón, Florencia Fernández; Coll, Moshe; Farji-Brener, Alejandro G; De Gabriel, Jane; Jurado, Enrique; Kyhn, Line A; Low, Bill; Mulder, Christa P H; Reardon-Smith, Kathryn; Rodríguez-Velázquez, Jorge; Seabloom, Eric W; Vesk, Peter A; van Cauter, An; Waldram, Matthew S; Zheng, Zheng; Blendinger, Pedro G; Enquist, Brian J; Facelli, Jose M; Knight, Tiffany; Majer, Jonathan D; Martínez-Ramos, Miguel; McQuillan, Peter; Prior, Lynda D

    2011-08-01

    • It has long been believed that plant species from the tropics have higher levels of traits associated with resistance to herbivores than do species from higher latitudes. A meta-analysis recently showed that the published literature does not support this theory. However, the idea has never been tested using data gathered with consistent methods from a wide range of latitudes. • We quantified the relationship between latitude and a broad range of chemical and physical traits across 301 species from 75 sites world-wide. • Six putative resistance traits, including tannins, the concentration of lipids (an indicator of oils, waxes and resins), and leaf toughness were greater in high-latitude species. Six traits, including cyanide production and the presence of spines, were unrelated to latitude. Only ash content (an indicator of inorganic substances such as calcium oxalates and phytoliths) and the properties of species with delayed greening were higher in the tropics. • Our results do not support the hypothesis that tropical plants have higher levels of resistance traits than do plants from higher latitudes. If anything, plants have higher resistance toward the poles. The greater resistance traits of high-latitude species might be explained by the greater cost of losing a given amount of leaf tissue in low-productivity environments.

  11. Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

    Science.gov (United States)

    Somerville, Chris R.; Scheible, Wolf

    2007-07-10

    Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  12. Heat shock protein 90 and its co-chaperone protein phosphatase 5 interact with distinct regions of the tomato I-2 disease resistance protein

    NARCIS (Netherlands)

    de la Fuente van Bentem, S.; Vossen, J.H.; de Vries, K.J.; van Wees, A.C.M.; Tameling, W.I.L.; Dekker, H.L.; de Koster, C.G.; Haring, M.A.; Takken, F.L.W.; Cornelissen, B.J.C.

    2005-01-01

    Recent data suggest that plant disease resistance (R) proteins are present in multi-protein complexes. Tomato R protein I-2 confers resistance against the fungal pathogen Fusarium oxysporum. To identify components of the I-2 complex, we performed yeast two-hybrid screens using the I-2 leucine-rich

  13. Achieving sustainable plant disease management through evolutionary principles.

    Science.gov (United States)

    Zhan, Jiasui; Thrall, Peter H; Burdon, Jeremy J

    2014-09-01

    Plants and their pathogens are engaged in continuous evolutionary battles and sustainable disease management requires novel systems to create environments conducive for short-term and long-term disease control. In this opinion article, we argue that knowledge of the fundamental factors that drive host-pathogen coevolution in wild systems can provide new insights into disease development in agriculture. Such evolutionary principles can be used to guide the formulation of sustainable disease management strategies which can minimize disease epidemics while simultaneously reducing pressure on pathogens to evolve increased infectivity and aggressiveness. To ensure agricultural sustainability, disease management programs that reflect the dynamism of pathogen population structure are essential and evolutionary biologists should play an increasing role in their design. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. RNAi: A Novel Approach for Plant Disease Management

    African Journals Online (AJOL)

    Shahnawaz

    2013-05-01

    May 1, 2013 ... Silencing specific genes by RNAi is a desirable natural solution ... applications of this novel technology in plant disease management for sustainable ... Further study of genetic host ... process of co-evolution, though therapeutic tools based ..... technology, it would be feasible to create a new biological.

  15. EFFECT OF SALINITY ON VIRAL DISEASE SPREAD IN PLANTS

    Directory of Open Access Journals (Sweden)

    Moldakimova N.A.

    2012-08-01

    Full Text Available Salt stress is an important factor affecting the quality and quantity of crop yields. The total area of the world’s land exposed salinity increased to 15% in 2011 compared to 7% in 2001. In addition, crops are susceptible to disease, which strongly affects the yield. Thus, viral diseases reduce crop yield, sometimes up to 80-100%, for example Eggplant mottled crinkle virus (EMCV can infect up to 100% yield of eggplant. Taken together, these two stress factors can cause enormous economic damage to agriculture. Despite of the importance, the effect of salinity on plant virus disease has not been well studied.In our study, we investigated the effect of high concentrations of salt (150mM NaCl on the systemic viral disease caused by EMCV. The virus causes the systemic necrosis in Nicotiana benthamiana. Systemic accumulation of virus at high concentrations of NaCl was drastically reduced. In the plants exposed to salt stress (100mM and 150mM NaCl for 21 days before infection systemic symptoms were significantly delayed. The relationship between plant responses to biotic and abiotic stress factors may indicate the existence of universal defensive pathways of plant adaptation to unfavorable conditions.

  16. Probiotic Diversity Enhances Rhizosphere Microbiome Function and Plant Disease Suppression

    Directory of Open Access Journals (Sweden)

    Jie Hu

    2016-12-01

    Full Text Available Bacterial communities associated with plant roots play an important role in the suppression of soil-borne pathogens, and multispecies probiotic consortia may enhance disease suppression efficacy. Here we introduced defined Pseudomonas species consortia into naturally complex microbial communities and measured the importance of Pseudomonas community diversity for their survival and the suppression of the bacterial plant pathogen Ralstonia solanacearum in the tomato rhizosphere microbiome. The survival of introduced Pseudomonas consortia increased with increasing diversity. Further, high Pseudomonas diversity reduced pathogen density in the rhizosphere and decreased the disease incidence due to both intensified resource competition and interference with the pathogen. These results provide novel mechanistic insights into elevated pathogen suppression by diverse probiotic consortia in naturally diverse plant rhizospheres. Ecologically based community assembly rules could thus play a key role in engineering functionally reliable microbiome applications.

  17. High-throughput phenotyping of plant resistance to aphids by automated video tracking.

    Science.gov (United States)

    Kloth, Karen J; Ten Broeke, Cindy Jm; Thoen, Manus Pm; Hanhart-van den Brink, Marianne; Wiegers, Gerrie L; Krips, Olga E; Noldus, Lucas Pjj; Dicke, Marcel; Jongsma, Maarten A

    2015-01-01

    Piercing-sucking insects are major vectors of plant viruses causing significant yield losses in crops. Functional genomics of plant resistance to these insects would greatly benefit from the availability of high-throughput, quantitative phenotyping methods. We have developed an automated video tracking platform that quantifies aphid feeding behaviour on leaf discs to assess the level of plant resistance. Through the analysis of aphid movement, the start and duration of plant penetrations by aphids were estimated. As a case study, video tracking confirmed the near-complete resistance of lettuce cultivar 'Corbana' against Nasonovia ribisnigri (Mosely), biotype Nr:0, and revealed quantitative resistance in Arabidopsis accession Co-2 against Myzus persicae (Sulzer). The video tracking platform was benchmarked against Electrical Penetration Graph (EPG) recordings and aphid population development assays. The use of leaf discs instead of intact plants reduced the intensity of the resistance effect in video tracking, but sufficiently replicated experiments resulted in similar conclusions as EPG recordings and aphid population assays. One video tracking platform could screen 100 samples in parallel. Automated video tracking can be used to screen large plant populations for resistance to aphids and other piercing-sucking insects.

  18. General mechanisms of drought response and their application in drought resistance improvement in plants.

    Science.gov (United States)

    Fang, Yujie; Xiong, Lizhong

    2015-02-01

    Plants often encounter unfavorable environmental conditions because of their sessile lifestyle. These adverse factors greatly affect the geographic distribution of plants, as well as their growth and productivity. Drought stress is one of the premier limitations to global agricultural production due to the complexity of the water-limiting environment and changing climate. Plants have evolved a series of mechanisms at the morphological, physiological, biochemical, cellular, and molecular levels to overcome water deficit or drought stress conditions. The drought resistance of plants can be divided into four basic types-drought avoidance, drought tolerance, drought escape, and drought recovery. Various drought-related traits, including root traits, leaf traits, osmotic adjustment capabilities, water potential, ABA content, and stability of the cell membrane, have been used as indicators to evaluate the drought resistance of plants. In the last decade, scientists have investigated the genetic and molecular mechanisms of drought resistance to enhance the drought resistance of various crops, and significant progress has been made with regard to drought avoidance and drought tolerance. With increasing knowledge to comprehensively decipher the complicated mechanisms of drought resistance in model plants, it still remains an enormous challenge to develop water-saving and drought-resistant crops to cope with the water shortage and increasing demand for food production in the future.

  19. AHAS herbicide resistance endowing mutations: effect on AHAS functionality and plant growth.

    Science.gov (United States)

    Yu, Qin; Han, Heping; Vila-Aiub, Martin M; Powles, Stephen B

    2010-09-01

    Twenty-two amino acid substitutions at seven conserved amino acid residues in the acetohydroxyacid synthase (AHAS) gene have been identified to date that confer target-site resistance to AHAS-inhibiting herbicides in biotypes of field-evolved resistant weed species. However, the effect of resistance mutations on AHAS functionality and plant growth has been investigated for only a very few mutations. This research investigates the effect of various AHAS resistance mutations in Lolium rigidum on AHAS functionality and plant growth. The enzyme kinetics of AHAS from five purified L. rigidum populations, each homozygous for the resistance mutations Pro-197-Ala, Pro-197-Arg, Pro-197-Gln, Pro-197-Ser or Trp-574-Leu, were characterized and the pleiotropic effect of three mutations on plant growth was assessed via relative growth rate analysis. All these resistance mutations endowed a herbicide-resistant AHAS and most resulted in higher extractable AHAS activity, with no-to-minor changes in AHAS kinetics. The Pro-197-Arg mutation slightly (but significantly) increased the K(m) for pyruvate and remarkably increased sensitivity to feedback inhibition by branched chain amino acids. Whereas the Pro-197-Ser and Trp-574-Leu mutations exhibited no significant effects on plant growth, the Pro-197-Arg mutation resulted in lower growth rates. It is clear that, at least in L. rigidum, these five AHAS resistance mutations have no major impact on AHAS functionality and hence probably no plant resistance costs. These results, in part, explain why so many Pro-197 AHAS resistance mutations in AHAS have evolved and why the Pro-197-Ser and the Trp-574-Leu AHAS resistance mutations are frequently found in many weed species.

  20. Characterization and genetics of multiple soybean aphid biotype resistance in five soybean plant introductions

    Science.gov (United States)

    Soybean aphid (Aphis glycines Matsumura) is the most important soybean [Glycine max (L.) Merr.] insect pest in the USA. The objectives of this study were to characterize the resistance expressed in the five plant introductions (PIs) to four soybean aphid biotypes, determine the mode of resistance in...

  1. Suppression of plant resistance gene-based immunity by a fungal effector

    NARCIS (Netherlands)

    Houterman, P.M.; Cornelissen, B.J.C.; Rep, M.

    2008-01-01

    The innate immune system of plants consists of two layers. The first layer, called basal resistance, governs recognition of conserved microbial molecules and fends off most attempted invasions. The second layer is based on Resistance (R) genes that mediate recognition of effectors, proteins secreted

  2. Genome-Wide Association Study on Resistance to Stalk Rot Diseases in Grain Sorghum.

    Science.gov (United States)

    Adeyanju, Adedayo; Little, Christopher; Yu, Jianming; Tesso, Tesfaye

    2015-04-16

    Stalk rots are important biotic constraints to sorghum production worldwide. Several pathogens may be associated with the disease, but Macrophomina phaseolina and Fusarium thapsinum are recognized as the major causal organisms. The diseases become more aggressive when drought and high-temperature stress occur during grain filling. Progress in genetic improvement efforts has been slow due to lack of effective phenotyping protocol and the strong environmental effect on disease incidence and severity. Deployment of modern molecular tools is expected to accelerate efforts to develop resistant hybrids. This study was aimed at identifying genomic regions associated with resistance to both causal organisms. A sorghum diversity panel consisting of 300 genotypes assembled from different parts of the world was evaluated for response to infection by both pathogens. Community resources of 79,132 single nucleotide polymorphic (SNP) markers developed on the panel were used in association studies using a multi-locus mixed model to map loci associated with stalk rot resistance. Adequate genetic variation was observed for resistance to both pathogens. Structure analysis grouped the genotypes into five subpopulations primarily based on the racial category of the genotypes. Fourteen loci and a set of candidate genes appear to be involved in connected functions controlling plant defense response. However, each associated SNP had relatively small effect on the traits, accounting for 19-30% of phenotypic variation. Linkage disequilibrium analyses suggest that significant SNPs are genetically independent. Estimation of frequencies of associated alleles revealed that durra and caudatum subpopulations were enriched for resistant alleles, but the results suggest complex molecular mechanisms underlying resistance to both pathogens. Copyright © 2015 Adeyanju et al.

  3. Selection and Assessment of Plant Growth-Promoting Rhizobacteria for Biological Control of Multiple Plant Diseases.

    Science.gov (United States)

    Liu, Ke; Newman, Molli; McInroy, John A; Hu, Chia-Hui; Kloepper, Joseph W

    2017-08-01

    A study was designed to screen individual strains of plant growth-promoting rhizobacteria (PGPR) for broad-spectrum disease suppression in vitro and in planta. In a preliminary screen, 28 of 196 strains inhibited eight different tested pathogens in vitro. In a secondary screen, these 28 strains showed broad spectrum antagonistic activity to six different genera of pathogens, and 24 of the 28 strains produced five traits reported to be related to plant growth promotion, including nitrogen fixation, phosphate solubilization, indole-3-acetic acid production, siderophore production, and biofilm formation. In advanced screens, the 28 PGPR strains selected in vitro were tested in planta for biological control of multiple plant diseases including bacterial spot of tomato caused by Xanthomonas axonopodis pv. vesicatoria, bacterial speck of tomato caused by Pseudomonas syringae pv. tomato, damping-off of pepper caused by Rhizoctonia solani, and damping-off of cucumber caused by Pythium ultimum. In all, 5 of the 28 tested strains significantly reduced three of the four tested diseases, and another 19 strains showed biological control to two tested diseases. To understand the observed broad-spectrum biocontrol capacity, antiSMASH was used to predict secondary metabolite clusters of selected strains. Multiple gene clusters encoding for secondary metabolites, e.g., bacillibactin, bacilysin, and microcin, were detected in each strain. In conclusion, selected individual PGPR strains showed broad-spectrum biocontrol activity to multiple plant diseases.

  4. Sphingolipids: the nexus between Gaucher disease and insulin resistance

    Directory of Open Access Journals (Sweden)

    Fuller Maria

    2010-10-01

    Full Text Available Abstract Sphingolipids constitute a diverse array of lipids in which fatty acids are linked through amide bonds to a long-chain base, and, structurally, they form the building blocks of eukaryotic membranes. Ceramide is the simplest and serves as a precursor for the synthesis of the three main types of complex sphingolipids; sphingomyelins, glycosphingolipids and gangliosides. Sphingolipids are no longer considered mere structural spectators, but bioactive molecules with functions beyond providing a mechanically stable and chemically resistant barrier to a diverse array of cellular processes. Although sphingolipids form a somewhat minor component of the total cellular lipid pool, their accumulation in certain cells forms the basis of many diseases. Human diseases caused by alterations in the metabolism of sphingolipids are conventionally inborn errors of degradation, the most common being Gaucher disease, in which the catabolism of glucosylceramide is defective and accumulates. Insulin resistance has been reported in patients with Gaucher disease and this article presents evidence that this is due to perturbations in the metabolism of sphingolipids. Ceramide and the more complex sphingolipids, the gangliosides, are constituents of specialised membrane microdomains termed lipid rafts. Lipid rafts play a role in facilitating and regulating lipid and protein interactions in cells, and their unique lipid composition enables them to carry out this role. The lipid composition of rafts is altered in cell models of Gaucher disease which may be responsible for impaired lipid and protein sorting observed in this disorder, and consequently pathology. Lipid rafts are also necessary for correct insulin signalling, and a perturbed lipid raft composition may impair insulin signalling. Unravelling common nodes of interaction between insulin resistance and Gaucher disease may lead to a better understanding of the biochemical mechanisms behind pathology.

  5. Efficacy of plant extracts in controlling wheat leaf rust disease caused by Puccinia triticina

    Directory of Open Access Journals (Sweden)

    Yasser M. Shabana

    2017-03-01

    Full Text Available The efficacy of eight plant extracts (garlic, clove, garden quinine, Brazilian pepper, anthi mandhaari, black cumin, white cedar and neem in controlling leaf rust disease of wheat was investigated in vitro and in vivo. In vitro, all treatments inhibited spore germination by more than 93%. Neem extract recorded 98.99% inhibition of spore germination with no significant difference from the fungicide Sumi-8 (100%. Under greenhouse conditions, seed soaking application in neem extract (at concentration of 2 ml/L resulted in 36.82% reduction in the number of pustules/leaf compared with the untreated control. Foliar spraying of plant extracts on wheat seedlings decreased the number of pustules/leaf. Foliar spraying of plant extracts four days after inoculation led to the highest resistance response of wheat plants against leaf rust pathogen. Spray application of wheat seedlings with neem, clove and garden quinine extracts, four days after inoculation with leaf rust pathogen completely prevented rust development (100% disease control and was comparable with the fungicide Sumi-8. Foliar spray application of wheat plants at mature stage with all plant extracts has significantly reduced the leaf rust infection (average coefficient of infection, ACI compared with the untreated control and neem was the most effective treatment. This was reflected on grain yield components, whereas the 1000-kernel weight and the test weight were improved whether under one- or two-spray applications, with two-spray application being more effective in this regard. Thus, it could be concluded that plant extracts may be useful to control leaf rust disease in Egypt as a safe alternative option to chemical fungicides.

  6. [Susceptible and resistant factors in neuro-immune disease].

    Science.gov (United States)

    Sato, Shinya; Kira, Jun-ichi

    2013-05-01

    Neuro-immune diseases (NIDs) are caused by a complex interaction between multiple genetic and environmental factors, both of which can have some impacts on susceptibility or resistance to each disease. Remarkable advance in genome technology made possible the effective screening of thousands of single nucleotide polymorphisms in thousands of samples. Additionally, epidemiological science, supported by microbiology, immunology and biochemistry, has revealed many possible environmental factors. Integrating genetic and environmental research data will pave the way to inform and personalize therapeutic decision-making in NIDs. This review aims to discuss susceptible and resistant factors that have attracted the most attention in the recent years, especially focusing on multiple sclerosis, which is one of the most common NIDs.

  7. Tobacco OPBP1 Enhances Salt Tolerance and Disease Resistance of Transgenic Rice

    Directory of Open Access Journals (Sweden)

    Xujun Chen

    2008-12-01

    Full Text Available Osmotin promoter binding protein 1 (OPBP1, an AP2/ERF transcription factor of tobacco, has been demonstrated to function in disease resistance and salt tolerance in tobacco. To increase stress tolerant capability of rice, we generated rice plants with an OPBP1 overexpressing construct. Salinity shock treatment with 250 mM NaCl indicated that most of the OPBP1 transgenic plants can survive, whereas the control seedlings cannot. Similar recovery was found by using the seedlings grown in 200 mM NaCl for two weeks. The OPBP1 transgenic and control plants were also studied for oxidative stress tolerance by treatment with paraquat, showing the transgenic lines were damaged less in comparison with the control plants. Further, the OPBP1 overexpression lines exhibited enhanced resistance to infections of Magnaporthe oryzae and Rhizoctonia solani pathogens. Gene expressing analysis showed increase in mRNA accumulation of several stress related genes. These results suggest that expression of OPBP1 gene increase the detoxification capability of rice.

  8. Enhanced Disease Susceptibility1 Mediates Pathogen Resistance and Virulence Function of a Bacterial Effector in Soybean.

    Science.gov (United States)

    Wang, Jialin; Shine, M B; Gao, Qing-Ming; Navarre, Duroy; Jiang, Wei; Liu, Chunyan; Chen, Qingshan; Hu, Guohua; Kachroo, Aardra

    2014-05-28

    Enhanced disease susceptibility1 (EDS1) and phytoalexin deficient4 (PAD4) are well-known regulators of both basal and resistance (R) protein-mediated plant defense. We identified two EDS1-like (GmEDS1a/GmEDS1b) proteins and one PAD4-like (GmPAD4) protein that are required for resistance signaling in soybean (Glycine max). Consistent with their significant structural conservation to Arabidopsis (Arabidopsis thaliana) counterparts, constitutive expression of GmEDS1 or GmPAD4 complemented the pathogen resistance defects of Arabidopsis eds1 and pad4 mutants, respectively. Interestingly, however, the GmEDS1 and GmPAD4 did not complement pathogen-inducible salicylic acid accumulation in the eds1/pad4 mutants. Furthermore, the GmEDS1a/GmEDS1b proteins were unable to complement the turnip crinkle virus coat protein-mediated activation of the Arabidopsis R protein Hypersensitive reaction to Turnip crinkle virus (HRT), even though both interacted with HRT. Silencing GmEDS1a/GmEDS1b or GmPAD4 reduced basal and pathogen-inducible salicylic acid accumulation and enhanced soybean susceptibility to virulent pathogens. The GmEDS1a/GmEDS1b and GmPAD4 genes were also required for Resistance to Pseudomonas syringae pv glycinea2 (Rpg2)-mediated resistance to Pseudomonas syringae. Notably, the GmEDS1a/GmEDS1b proteins interacted with the cognate bacterial effector AvrA1 and were required for its virulence function in rpg2 plants. Together, these results show that despite significant structural similarities, conserved defense signaling components from diverse plants can differ in their functionalities. In addition, we demonstrate a role for GmEDS1 in regulating the virulence function of a bacterial effector.

  9. Fluconazole resistance in cryptococcal disease: emerging or intrinsic?

    Science.gov (United States)

    Cheong, Jenny Wan Sai; McCormack, Joe

    2013-04-01

    With the widespread use of long-term fluconazole prophylaxis and suppressive treatment, the potential development of fluconazole resistance poses a threat to the management of cryptococcal disease. Interpretive breakpoints for the in vitro antifungal susceptibility testing of C. neoformans have not been established and it is unclear whether the fluconazole minimum inhibitory concentration (MIC) is clinically relevant. To gain insight into the management of patients with cryptococcosis who fail fluconazole therapy, we conducted a PubMed literature search for cases of fluconazole-resistant cryptococcosis reported from 1991 to 2011. A total of 20 such cases were identified in which most patients had AIDS and 30% had never had prior exposure to fluconazole. Fluconazole failure in patients with cryptococcal disease cannot be fully attributed to emerging resistance of the etiologic agent and heteroresistance is a potential alternative mechanism. There is a need to refine the definition of fluconazole-resistant cryptococcosis and additional studies of such patients will improve treatment strategies and outcomes.

  10. Osmoregulation Mechanism of Drought Stress and Genetic Engineering Strategies for Improving Drought Resistance in Plants

    Institute of Scientific and Technical Information of China (English)

    Du Jinyou; Chen Xiaoyang; Li Wei; Gao Qiong

    2004-01-01

    Drought, one of the main adverse environmental factors, obviously affected plant growth and development. Many adaptive strategies have been developed in plants for coping with drought or water stress, among which osmoregulation is one of the important factors of plant drought tolerance. Many substances play important roles in plant osmoregulation for drought resistance, including proline, glycine betaine, Lea proteins and soluble sugars such as levan, trehalose, sucrose, etc. The osmoregulation mechanism and the genetic engineering of plant drought-tolerance are reviewed in this paper.

  11. Enhancement of resistance to aphids by introducing the snowdrop lectin gene gna into maize plants.

    Science.gov (United States)

    Wang, Zhaoyu; Zhang, Kewei; Sun, Xiaofen; Tang, Kexuan; Zhang, Juren

    2005-12-01

    In order to enhance the resistance to pests, transgenic maize (Zea mays L.) plants from elite inbred lines containing the gene encoding snowdrop lectin (Galanthus nivalis L. agglutinin; GNA) under control of a phloem-specific promoter were generated through the Agrobacterium tumefaciens-mediated method. The toxicity of GNA-expressing plants to aphids has also been studied. The independently derived plants were subjected to molecular analyses. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that the gna gene was integrated into maize genome and inherited to the following generations. The typical Mendelian patterns of inheritance occurred in most cases. The level of GNA expression at 0.13%-0.28% of total soluble protein was observed in different transgenic plants. The progeny of nine GNA-expressing independent transformants that were derived separately from the elite inbred lines DH4866, DH9942, and 8902, were selected for examination of resistance to aphids. These plants synthesized GNA at levels above 0.22% total soluble protein, and enhanced resistance to aphids was demonstrated by exposing the plants to corn leaf aphid (Rhopalosiphum maidis Fitch) under greenhouse conditions. The nymph production was significantly reduced by 46.9% on GNA-expressing plants. Field evaluation of the transgenic plants supported the results from the inoculation trial. After a series of artificial self-crosses, some homozygous transgenic maize lines expressing GNA were obtained. In the present study, we have obtained new insect-resistant maize material for further breeding work.

  12. Kanamycin resistance during in vitro development of pollen from transgenic tomato plants

    NARCIS (Netherlands)

    Bino, R.J.; Hille, J.; Franken, J.

    1987-01-01

    Effects of kanamycin on pollen germination and tube growth of pollen from non-transformed plants and from transgenic tomato plants containing a chimaeric kanamycin resistance gene were determined. Germination of pollen was not affected by the addition of kanamycin to the medium in both genotypes. Ka

  13. Antibacterial activity of plant extracts and phytochemicals on antibiotic-resistant bacteria

    OpenAIRE

    Nascimento,Gislene G. F.; Locatelli,Juliana; Freitas,Paulo C.; Silva,Giuliana L.

    2000-01-01

    The antimicrobial activity of plant extracts and phytochemicals was evaluated with antibiotic susceptible and resistant microorganisms. In addition, the possible synergistic effects when associated with antibiotics were studied. Extracts from the following plants were utilized: Achillea millifolium (yarrow), Caryophyllus aromaticus (clove), Melissa offficinalis (lemon-balm), Ocimun basilucum (basil), Psidium guajava (guava), Punica granatum (pomegranate), Rosmarinus officinalis (rosemary), Sa...

  14. Enhancement of resistance to aphids by introducing the snowdrop lectin gene gna into maize plants

    Indian Academy of Sciences (India)

    Zhaoyu Wang; Kewei Zhang; Xiaofen Sun; Kexuan Tang; Juren Zhang

    2005-12-01

    In order to enhance the resistance to pests, transgenic maize (Zea mays L.) plants from elite inbred lines containing the gene encoding snowdrop lectin (Galanthus nivalis L. agglutinin; GNA) under control of a phloemspecific promoter were generated through the Agrobacterium tumefaciens-mediated method. The toxicity of GNA-expressing plants to aphids has also been studied. The independently derived plants were subjected to molecular analyses. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that the gna gene was integrated into maize genome and inherited to the following generations. The typical Mendelian patterns of inheritance occurred in most cases. The level of GNA expression at 0.13%–0.28% of total soluble protein was observed in different transgenic plants. The progeny of nine GNA-expressing independent transformants that were derived separately from the elite inbred lines DH4866, DH9942, and 8902, were selected for examination of resistance to aphids. These plants synthesized GNA at levels above 0.22% total soluble protein, and enhanced resistance to aphids was demonstrated by exposing the plants to corn leaf aphid (Rhopalosiphum maidis Fitch) under greenhouse conditions. The nymph production was significantly reduced by 46.9% on GNA-expressing plants. Field evaluation of the transgenic plants supported the results from the inoculation trial. After a series of artificial self-crosses, some homozygous transgenic maize lines expressing GNA were obtained. In the present study, we have obtained new insect-resistant maize material for further breeding work.

  15. Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Hua eLu

    2013-06-01

    Full Text Available Emerging devastating diseases, such as Huanglongbing (HLB and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA is a key signaling molecule involved in basal defense and resistance (R-gene mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, ctNDR1. Overexpression of ctNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PR1. In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that ctNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production.

  16. Insulin Resistance and Risk of Cardiovascular Disease in Postmenopausal Women

    DEFF Research Database (Denmark)

    Schmiegelow, Michelle D; Hedlin, Haley; Stefanick, Marcia L

    2015-01-01

    BACKGROUND: Insulin resistance is associated with diabetes mellitus, but it is uncertain whether it improves cardiovascular disease (CVD) risk prediction beyond traditional cardiovascular risk factors. METHODS AND RESULTS: We identified 15,288 women from the Women's Health Initiative Biomarkers s......-cholesterol and did not provide independent prognostic information in postmenopausal women without diabetes mellitus. CLINICAL TRIAL REGISTRATION INFORMATION: URL: http://www.clinicaltrial.gov. Unique identifier: NCT00000611....

  17. Pathophysiology of resistant hypertension in chronic kidney disease.

    Science.gov (United States)

    Campese, Vito M

    2014-01-01

    Hypertension associated with chronic kidney diseases often is resistant to drug treatment. This review deals with two main aspects of the management of CKD patients with hypertension: the role of sodium/volume and the need for dietary salt restriction, as well as appropriate use of diuretics and what currently is called sequential nephron blockade; the second aspect that is addressed extensively in this review is the role of the sympathetic nervous system and the possible clinical use of renal denervation.

  18. An Approach Towards Structure Based Antimicrobial Peptide Design for Use in Development of Transgenic Plants: A Strategy for Plant Disease Management.

    Science.gov (United States)

    Ilyas, Humaira; Datta, Aritreyee; Bhunia, Anirban

    2017-01-01

    Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), are ubiquitous and vital components of innate defense response that present themselves as potential candidates for drug design, and aim to control plant and animal diseases. Though their application for plant disease management has long been studied with natural AMPs, cytotoxicity and stability related shortcomings for the development of transgenic plants limit their usage. Newer technologies like molecular modelling, NMR spectroscopy and combinatorial chemistry allow screening for potent candidates and provide new avenues for the generation of rationally designed synthetic AMPs with multiple biological functions. Such AMPs can be used for the control of plant diseases that lead to huge yield losses of agriculturally important crop plants, via generation of transgenic plants. Such approaches have gained significant attention in the past decade as a consequence of increasing antibiotic resistance amongst plant pathogens, and the shortcomings of existing strategies that include environmental contamination and human/animal health hazards amongst others. This review summarizes the recent trends and approaches used for employing AMPs, emphasizing on designed/modified ones, and their applications toward agriculture and food technology. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. The Xanthomonas campestris effector protein XopDXcc8004 triggers plant disease tolerance by targeting DELLA proteins.

    Science.gov (United States)

    Tan, Leitao; Rong, Wei; Luo, Hongli; Chen, Yinhua; He, Chaozu

    2014-11-01

    Plants protect themselves from the harmful effects of pathogens by resistance and tolerance. Disease resistance, which eliminates pathogens, can be modulated by bacterial type III effectors. Little is known about whether disease tolerance, which sustains host fitness with a given pathogen burden, is regulated by effectors. Here, we examined the effects of the Xanthomonas effector protein XopDXcc8004 on plant disease defenses by constructing knockout and complemented Xanthomonas strains, and performing inoculation studies in radish (Raphanus sativus L. var. radiculus XiaoJinZhong) and Arabidopsis plants. XopDXcc8004 suppresses disease symptoms without changing bacterial titers in infected leaves. In Arabidopsis, XopDXcc8004 delays the hormone gibberellin (GA)-mediated degradation of RGA (repressor of ga1-3), one of five DELLA proteins that repress GA signaling and promote plant tolerance under biotic and abiotic stresses. The ERF-associated amphiphilic repression (EAR) motif-containing region of XopDXcc8004 interacts with the DELLA domain of RGA and might interfere with the GA-induced binding of GID1, a GA receptor, to RGA. The EAR motif was found to be present in a number of plant transcriptional regulators. Thus, our data suggest that bacterial pathogens might have evolved effectors, which probably mimic host components, to initiate disease tolerance and enhance their survival.

  20. Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases

    Directory of Open Access Journals (Sweden)

    Rosa A. Malvar

    2010-02-01

    Full Text Available Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular between polysaccharides, between polysaccharides and lignin and, between polysaccharides