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

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. (c) 2009 Society of Chemical Industry.

Molecular identification of GAPDHs in cassava highlights the antagonism of MeGAPCs and MeATG8s in plant disease resistance against cassava bacterial blight.

Science.gov (United States)

Zeng, Hongqiu; Xie, Yanwei; Liu, Guoyin; Lin, Daozhe; He, Chaozu; Shi, Haitao

2018-06-01

MeGAPCs were identified as negative regulators of plant disease resistance, and the interaction of MeGAPCs and MeATG8s was highlighted in plant defense response. As an important enzyme of glycolysis metabolic pathway, glyceraldehyde-3-P dehydrogenase (GAPDH) plays important roles in plant development, abiotic stress and immune responses. Cassava (Manihot esculenta) is most important tropical crop and one of the major food crops, however, no information is available about GAPDH gene family in cassava. In this study, 14 MeGAPDHs including 6 cytosol GAPDHs (MeGAPCs) were identified from cassava, and the transcripts of 14 MeGAPDHs in response to Xanthomonas axonopodis pv manihotis (Xam) indicated their possible involvement in immune responses. Further investigation showed that MeGAPCs are negative regulators of disease resistance against Xam. Through transient expression in Nicotiana benthamiana, we found that overexpression of MeGAPCs led to decreased disease resistance against Xam. On the contrary, MeGAPCs-silenced cassava plants through virus-induced gene silencing (VIGS) conferred improved disease resistance. Notably, MeGAPCs physically interacted with autophagy-related protein 8b (MeATG8b) and MeATG8e and inhibited autophagic activity. Moreover, MeATG8b and MeATG8e negatively regulated the activities of NAD-dependent MeGAPDHs, and are involved in MeGAPCs-mediated disease resistance. Taken together, this study highlights the involvement of MeGAPCs in plant disease resistance, through interacting with MeATG8b and MeATG8e.

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

The effector SPRYSEC-19 of Globodera rostochiensis suppresses CC-NB-LRR-mediated disease resistance in plants.

Science.gov (United States)

Postma, Wiebe J; Slootweg, Erik J; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O G; van Gelderen, Kasper; Lozano-Torres, Jose L; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

2012-10-01

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 to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants.

Mutation breeding for disease resistance in wheat and field beans

International Nuclear Information System (INIS)

Abdel-Hak, T.M.; Kamel, A.H.

1977-01-01

Wheat and broad-bean diseases cause considerable losses under Egyptian conditions; therefore, an attempt was made to induce useful mutations in both crops resistant to diseases which may be of direct or indirect use in breeding programmes. The methodology of artificial inoculation, evaluation, selection, radiation levels used are reported, in addition to the economic importance of the varieties used. This work passed through two phases, the first started in the 1972/73 crop season with a small population, while the second in 1974/75 with a larger one to have a better chance of detecting resistant mutants. In the first phase, a total of 3563M 1 wheat plants was grown in addition to approximately 3600-44,000M 2 and 77,646M 3 plants. Twenty-two M 2 plants were selected as showing lower level of leaf rust development, but further tests showed these plants are not true mutants since they rusted at the same level of their parent varieties. Out of the M 3 plants none showed good resistance. In the second phase, 36,000, 277,080 and 289,492 plants of M 1 , M 2 and M 3 , respectively, were grown and 73M 2 plants were selected as showing complete resistance to leaf and stem rusts. In field beans out of the first phase, a total of 5760, 37,200 and 33,240M 1 , M 2 and M 3 plants, respectively, was grown and none showed a good level of disease resistance although some were less diseased. These were further tested and proved not true mutants for reduced disease development. In the second phase, 8747, 203,520 and 90,285 plants of M 1 , M 2 and M 3 , respectively, were grown and 27M 2 plants were selected as showing a lower level of chocolate spot and rust development. The paper also discusses the use of single versus composite cultures in mutation breeding for disease resistance. (author)

Dissection and Manipulation of LRR Domains in Plant Disease Resistance Gene Products.

Energy Technology Data Exchange (ETDEWEB)

Bent, Andrew [Univ. of Wisconsin, Madison, WI (United States)

2012-11-28

Leucine-rich repeat (LRR) protein domains offer a readily diversifiable platform - literally, an extended protein surface - for specific binding of very diverse ligands. The project addressed the following overlapping research questions: How do leucine-rich repeat proteins recognize their cognate ligands? What are the intra- and inter-molecular transitions that occur that cause transmembrane LRR proteins to switch between off and on states? How do plants use LRR receptor proteins to activate disease resistance? Can we synthetically evolve new LRR proteins that have acquired new ligand specificities?

Induced resistance to rust disease in lentil

International Nuclear Information System (INIS)

Paul, Amitava; Singh, D.P.

2006-01-01

Considerable yield reduction in lentil is due to rust caused by Uromyces fabae. So far the sources of resistance to rust are available in the small seeded background. There is a need to develop rust resistant/tolerant bold seeded cultivars. Mutations were induced by gamma rays (10 and 15 kR) for incorporating resistance to rust in K-75(Mallika), a high yielding bold seeded, but rust susceptible cultivar at Pantnagar which is the hot spot for this disease. Dry seeds (300) were irradiated for each treatment. In M 1 generation, individual plants from each treatment were selfed and harvested separately which constituted the M 2 generation. In M 2 individual plant progenies were scored following a rating scale of 1 (Free) to 9(highly susceptible). At 15 kR dose, 8 plants were resistant (score 3.0) and 14 plants were tolerant (score 5.0) to rust, while in control and 10 kR populations, all plants were susceptible or highly susceptible having score of 7 or 9, respectively. The M 2 plants segregated in ratio of 1 resistant: 3 susceptible. The progenies of resistant/tolerant M 2 plants were bred true in the M 3 generation suggesting that the resistance to rust is controlled by one recessive gene. (author)

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

Mapping X-Disease Phytoplasma Resistance in Prunus virginiana

OpenAIRE

Ryan R. Lenz; Wenhao Dai

2017-01-01

Phytoplasmas such as “Candidatus Phytoplasma pruni,” the causal agent of X-disease of stone fruits, lack detailed biological analysis. This has limited the understanding of plant resistance mechanisms. Chokecherry (Prunus virginiana L.) is a promising model to be used for the plant-phytoplasma interaction due to its documented ability to resist X-disease infection. A consensus chokecherry genetic map “Cho” was developed with JoinMap 4.0 by joining two parental maps. The new map contains a com...

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

Science.gov (United States)

Hammerschmidt, Ray

2018-05-01

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.

Evolution of high yielding chickpea varieties, having improved plant type and disease resistance, through induced mutations

International Nuclear Information System (INIS)

Sadiq, M.; Hussan, M.; Haq, M.A.

1989-01-01

The breeding programme on the use of induced mutations, in chickpea for genetic variability for better plant type, grain yield and disease resistance has been started. The chickpea mutant variety is one of the leading varieties being extensively grown throughout Pakistan and has played its role in stabilizing the chickpea production in the country. Four chickpea varieties were treated, each with two dosed of gamma rays. The main purpose of the mutagenic treatment of these varieties/cultivars, was induce multiple resistance. (A.B.)

Plant Growth Enhancement, Disease Resistance, and Elemental Modulatory Effects of Plant Probiotic Endophytic Bacillus sp. Fcl1.

Science.gov (United States)

Jayakumar, Aswathy; Krishna, Arathy; Mohan, Mahesh; Nair, Indu C; Radhakrishnan, E K

2018-04-13

Endophytic bacteria have already been studied for their beneficial support to plants to manage both biotic and abiotic stress through an array of well-established mechanisms. They have either direct or indirect impact on mobilizing diverse nutrients and elements from soil to plants. However, detailed insight into the fine-tuning of plant elemental composition by associated microorganism is very limited. In this study, endophytic Bacillus Fcl1 characterized from the rhizome of Curcuma longa was found to have broad range of plant growth-promoting and biocontrol mechanisms. The organism was found to have indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase production properties along with nitrogen fixation. The Bacillus Fcl1 could also inhibit diverse phytopathogens as confirmed by dual culture and well diffusion. By LC-MS/MS analysis, chemical basis of its antifungal activity has been proved to be due to the production of iturin A and a blend of surfactin compounds. Moreover, the organism was found to induce both plant growth and disease resistance in vivo in model plant system. Because of these experimentally demonstrated multiple plant probiotic features, Bacillus Fcl1 was selected as a candidate organism to study its role in modulation of plant elemental composition. ICP-MS analysis of Bacillus Fcl1-treated plants provided insight into relation of bacterial interaction with elemental composition of plants.

Induced mutations for disease resistance in wheat and field beans

International Nuclear Information System (INIS)

Abdel-Hak, T.M.; Kamel, A.H.

1976-01-01

Wheat disease in Egypt is reviewed and results of mutation breeding by γ irradiation for disease resistance in wheat and field beans are described. Wheat mutants of the variety Giza 155 resistant to leaf rust, Giza 156 resistant to both leaf and yellow rusts, and Tosson with a reasonable level of combined resistance to the three rusts in addition to mutants of the tetraploid variety Dakar 52 with a good level of stem and yellow rust resistance are required. Their seeds were subjected to 10, 15 and 20 krad. Of 3000-3700 M 2 plants from each variety and dosage, 22 plants from both Giza 155 and Giza 156, although susceptible, showed a lower level of disease development. In 1975, M 3 families of these selected plants and 6000 plants from bulked material were grown from each variety and dosage at two locations. Simultaneously, an additional population consisting of 3000 mutagen-treated seeds was grown to have a reasonable chance of detecting mutants; 2 heads from each plant were harvested. These will be grown next season (1976) to make a population of 25,000-30,000 M 2 plants and screened to composite cultures of specific rusts. Vicia faba seeds of field bean varieties Giza 1, Giza 2 and Rebaya 40, equally susceptible to rust and chocolate spot, were subjected to 3, 5 and 7 krad of 60 Co gamma radiation and 800 M 1 plants were grown in 1972 per variety and dose. Up to this later growing season (M 3 ) no resistance was detected in M 3 plank

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.

In vitro screening methods for assessing plant disease resistance

International Nuclear Information System (INIS)

Lebeda, A.; Svabova, L.

2010-01-01

A combination of biotechnological and phytopathological techniques provides an alternative approach to classical resistance breeding methods. Such techniques have been increasingly used since the 1980s, in parallel with the progress in plant biotechnology. In the approach of resistance screening and selection in vitro, both experimental objects, i.e., the plant and the pathogen, must first be transferred to in vitro conditions, and finally, the plant material must be transferred back to in vivo conditions and adapted to the outside settings. Specific attention must be paid to the methods of pathogen preparation for use in screening and selection in vitro. The selection agents are classified according to their origin, the methods of preparation, nature and content of active substances, and effective utilisation for screening or selection in vitro. Basic principles and methodological aspects of the in vitro work (explant cultures, sources of in vitro variability, screening and selection methods, types of selection agents) as well as examples of practical applications in the breeding of different crops are critically reviewed in this chapter. (author)

Nuclear techniques in plant pathology 1. Plant disease control and physiology of parasitism

International Nuclear Information System (INIS)

Menten, J.O.M.; Ando, A.; Tulmann Neto, A.

1986-01-01

Nuclear techniques are advantageously used in several areas of plant pathology. Among them are: induction of mutation for disease resistance, studies with pesticides, disease control through pathogen inactivation, induction of variability and stimulation in pathogens and natural enemies, studies of microorganism physiology and diseased plant physiology, effect of gamma radiation on pesticides, technology of pesticides application, etc. (Author) [pt

Mapping X-Disease Phytoplasma Resistance in Prunus virginiana.

Science.gov (United States)

Lenz, Ryan R; Dai, Wenhao

2017-01-01

Phytoplasmas such as " Candidatus Phytoplasma pruni," the causal agent of X-disease of stone fruits, lack detailed biological analysis. This has limited the understanding of plant resistance mechanisms. Chokecherry ( Prunus virginiana L.) is a promising model to be used for the plant-phytoplasma interaction due to its documented ability to resist X-disease infection. A consensus chokecherry genetic map "Cho" was developed with JoinMap 4.0 by joining two parental maps. The new map contains a complete set of 16 linkage groups, spanning a genetic distance of 2,172 cM with an average marker density of 3.97 cM. Three significant quantitative trait loci (QTL) associated with X-disease resistance were identified contributing to a total of 45.9% of the phenotypic variation. This updated genetic linkage map and the identified QTL will provide the framework needed to facilitate molecular genetics, genomics, breeding, and biotechnology research concerning X-disease in chokecherry and other Prunus species.

Mapping X-Disease Phytoplasma Resistance in Prunus virginiana

Directory of Open Access Journals (Sweden)

Ryan R. Lenz

2017-11-01

Full Text Available Phytoplasmas such as “Candidatus Phytoplasma pruni,” the causal agent of X-disease of stone fruits, lack detailed biological analysis. This has limited the understanding of plant resistance mechanisms. Chokecherry (Prunus virginiana L. is a promising model to be used for the plant-phytoplasma interaction due to its documented ability to resist X-disease infection. A consensus chokecherry genetic map “Cho” was developed with JoinMap 4.0 by joining two parental maps. The new map contains a complete set of 16 linkage groups, spanning a genetic distance of 2,172 cM with an average marker density of 3.97 cM. Three significant quantitative trait loci (QTL associated with X-disease resistance were identified contributing to a total of 45.9% of the phenotypic variation. This updated genetic linkage map and the identified QTL will provide the framework needed to facilitate molecular genetics, genomics, breeding, and biotechnology research concerning X-disease in chokecherry and other Prunus species.

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.

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

Potential biochemical markers for selection of disease resistance in Vigna radiata

International Nuclear Information System (INIS)

Badere, R.S.; Koche, D.K.; Choudhary, A.D.; Pawar, S.E.

2001-01-01

The Vigna radiata (L.) Wilczek (Green gram), a major pulse crop is prone to damaging diseases caused by Erysiphe polygoni, Cercospora canescens and Rhizoctonia sp. Therefore, the development of multiple resistance is a major breeding objective in green gram. Resistance to powdery mildew has already been developed, however, there are no reports on the development of resistance to Cercospora in green gram. Owing to limitation of conventional screening methods, the improvement for multiple disease resistance is inadequate, in this crop. It needs an efficient and quick selection method, for screening the plant population at an early stage. It is well established that the resistant interaction, in plants, involves accumulation of antibiotic compound phytoalexin (Genestein in Vigna radiata) and induction of enzymes such as β-1,3 gulcanase and Chitinases. These compounds are not only induced by pathogens but also pathogen-derived elicitors. These biochemical compounds can be used as resistance indicative biochemical markers for screening the natural or mutagen induced genetic diversity in populations of Vigna radiata in non-destructive manner. It, however, needs a systematic study of plant defense response. This paper deals with the response of resistant and susceptible cultivars of vigna radiata to Cercospora elicitor and development of non-destructive selection method for disease resistance. (author)

Influences of the disease resistance conferred by the individual ...

African Journals Online (AJOL)

To research possible influences of the disease resistance conferred by different trans-resistance genes on the transgenic rice plants in their yields and grain quality, three transgenic rice lines, including two with the resistance genes Pi-d2 and Pi-d3, respectively, for rice blast, and one with the resistance gene Xa21 for rice ...

The molecular basis of disease resistance in higher plants

African Journals Online (AJOL)

xxxxxx

Therefore, manipulating a single transcription factor could have the same effect as manipulating a set of specific genes within the plant. As highlighted above, transgenic plants allow the targeted ... including molecular techniques and genetics will provide insights into pathogen-defense mechanism and subsequent disease ...

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

NARCIS (Netherlands)

Loon, L.C. van

1997-01-01

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

The Effector SPRYSEC-19 of Globodera rostochiensis Suppresses CC-NB-LRR-Mediated Disease Resistance in Plants1[C][W][OA

Science.gov (United States)

Postma, Wiebe J.; Slootweg, Erik J.; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O.G.; van Gelderen, Kasper; Lozano-Torres, Jose L.; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

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 to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants. PMID:22904163

Possibilities of avoidance and control of bacterial plant diseases when using pathogen-tested (certified) or - treated planting material

NARCIS (Netherlands)

Janse, J.; Wenneker, M.

2002-01-01

Testing of planting material for freedom from phytopathogenic bacteria is an important, although not exclusive, method for control of bacterial diseases of plants. Ideally, pathogen-free or pathogen-/disease-resistant planting material is desirable, but this situation is not always possible on a

Rice Gene Network Inferred from Expression Profiling of Plants Overexpressing OsWRKY13,a Positive Regulator of Disease Resistance

Institute of Scientific and Technical Information of China (English)

Deyun Qiu; Jun Xiao; Weibo Xie; Hongbo Liu; Xianghua Li; Lizhong Xiong; Shiping Wang

2008-01-01

Accumulating information indicates that plant disease resistance signaling pathways frequently interact with other pathways regulating developmental processes or abiotic stress responses. However, the molecular mechanisms of these types of crosstalk remain poorly understood in most cases. Here we report that OsWRKY13, an activator of rice resistance to both bacterial and fungal pathogens, appears to function as a convergent point for crosstalk among the pathogen-induced salicylate-dependent defense pathway and five other physiologic pathways. Genome-wide analysis of the expression profiles of OsWRKY13-overexpressing lines suggests that OsWRKY13 directly or indirectly regulates the expression of more than 500 genes that are potentially involved in different physiologic processes according to the classification of the Gene Ontology database. By comparing the expression patterns of genes functioning in known pathways or cellular processes of pathogen infection and the phenotypes between OsWRKY13-overexpressing and wildtype plants, our data suggest that OsWRKY13 is also a regulator of other physiologic processes during pathogen infection. The OsWRKY13-associated disease resistance pathway synergistically interacts via OsWRKY13 with the glutathione/glutaredoxin system and flavonoid biosynthesis pathway to monitor redox homeostasis and to putatively enhance the biosynthesis of antimicrobial flavonoid phytoalexins, respectively, in OsWRKY13-overexpressing lines. Meanwhile, the OsWRKY13-associated disease resistance pathway appears to interact antagonistically with the SNAC1-mediated abiotic stress defense pathway, jasmonic acid signaling pathway, and terpenoid metabolism pathway via OsWRKY13 to suppress salt and cold defense responses as well as to putatively retard rice growth and development.

The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

Science.gov (United States)

Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

2017-07-01

The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Prospects of Understanding the Molecular Biology of Disease Resistance in Rice

Directory of Open Access Journals (Sweden)

Pankaj Kumar Singh

2018-04-01

Full Text Available Rice is one of the important crops grown worldwide and is considered as an important crop for global food security. Rice is being affected by various fungal, bacterial and viral diseases resulting in huge yield losses every year. Deployment of resistance genes in various crops is one of the important methods of disease management. However, identification, cloning and characterization of disease resistance genes is a very tedious effort. To increase the life span of resistant cultivars, it is important to understand the molecular basis of plant host–pathogen interaction. With the advancement in rice genetics and genomics, several rice varieties resistant to fungal, bacterial and viral pathogens have been developed. However, resistance response of these varieties break down very frequently because of the emergence of more virulent races of the pathogen in nature. To increase the durability of resistance genes under field conditions, understanding the mechanismof resistance response and its molecular basis should be well understood. Some emerging concepts like interspecies transfer of pattern recognition receptors (PRRs and transgenerational plant immunitycan be employed to develop sustainable broad spectrum resistant varieties of rice.

Mutation breeding for disease resistance using in-vitro culture techniques

International Nuclear Information System (INIS)

1985-07-01

Breeding for disease resistance is a major aspect of plant breeding, which may take at least 20% of a plant breeder's time, effort and budget. Nevertheless, numerous resistance problems remain unsolved and present major constraints to the production of food, feed, fiber and industrial commodities. The application of novel biotechnology and genetic engineering will extend the possibilities of conventional plant breeding. Therefore a meeting of experts in plant protection, plant breeding and in-vitro culture technology was convened by the Joint FAO/IAEA Division in Vienna. The experts were asked to discuss and give advice on prospects of biotechnology, especially plant in-vitro cultures, to contribute towards improved chances of success in mutation breeding for disease resistance. The plant breeder, in searching for resistance to a particular pathogen, like for any other desirable character, needs genetic variation to begin with. In addition he needs an appropriate screening method to detect the desired character. Science has developed so fast that it is now time to apply the existing knowledge of biotechnology to practical problems in agriculture, also in developing countries. In the near future this may be true also for novel techniques of genetic engineering. The usefulness and feasibility of the application of in-vitro techniques for these purposes varies with crops and pathogens, but also depends on the strength of plant breeding and plant pathology and the facilities available in a particular country. The members of the Advisory Group attempted to discuss the various aspects and to reach sound conclusions

Disease-induced assemblage of a plant-beneficial bacterial consortium

DEFF Research Database (Denmark)

Berendsen, Roeland L.; Vismans, Gilles; Yu, Ke

2018-01-01

Disease suppressive soils typically develop after a disease outbreak due to the subsequent assembly of protective microbiota in the rhizosphere. The role of the plant immune system in the assemblage of a protective rhizosphere microbiome is largely unknown. In this study, we demonstrate...... in a second population of plants growing in the same soil. Together our results indicate that plants can adjust their root microbiome upon pathogen infection and specifically recruit a group of disease resistance-inducing and growth-promoting beneficial microbes, therewith potentially maximizing the chance...

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

Plant biotechnology and implications for rapeseed agronomy: development of new methods of pest and disease control

Energy Technology Data Exchange (ETDEWEB)

Maas, C. [Hoechst Schering AgrEvo GmbH, Frankfurt am Main (Germany)

1998-12-31

The last years several strategies are becoming available for molecular breeding to improve resistance of transgenic plants against pests. Generally, transgenic plants expressing antifungal proteins (chitinase, glucanase and RIP) have been effectively protected against a variety of fungal diseases, whereas symbiotic mycorrhizal fungi remain unaffected. Other antifungal strategies, such as artificial localized cell death, do exist for pyramiding strategies against fungal diseases. Insect predation has been controlled by expression of insect specific proteins from the bacterium Bacillus thuringensis (B.t.-toxin). A combination with other genes coding for insecticidal proteins in a transgenic plant could further enhance protection of plants against insect pests. Control of viral diseases in transgenic plants was achieved by overexpression of coat- or movement protein from the virus itself, which limits replication and spread in the plants. Other viral genes, or subgenomic fragments, either in sense or antisense orientation effectively conferred resistance to viral diseases. Several strategies also become available to engineer resistance against bacterial diseases and nemathode attack. Expression of proteinase inhibitors, active against nematodes, or specific physiological manipulation which leads to the collapse of feeding cells of sedentary nematodes has been shown to control nematode pests. This demonstrates that a fair number of strategies already exists to control plant pests by molecular breeding. In several cases a combination of different resistance strategies in one and the same plant has been shown to exert synergistic protective effects. In future, this probably will reduce the emergence of resistance breaking strains leading to genetically engineered plants with improved and stable resistance characteristics. The use of genetic engineering in resistance breeding as part of integrated pest management clearly could lead to a more ecologically sustainable

Plant breeding for resistance to insect pests: Considerations about the use of induced mutations

International Nuclear Information System (INIS)

1978-01-01

The Panel was intended to stimulate proposals on specific plant breeding objectives, for immediate and long term solution. Nine papers considered the host plant resistance to particular insect pests in a variety of cases. The desirability of achieving some measure of pest control via the development of disease-resistant mutants was discussed. In its conclusions, the Panel stressed the need to consider host plant resistance as one of the primary lines of defense in all pest management programmes. Consequently, resistance to insects was recommended to become an integral part of plant breeding programmes. Preference might need to be given to developing insect resistance in those crop plants for which practical control is lacking or where current methods of pest control present critical environmental hazards. The roles of the IAEA and FAO in such projects is outlined. Guidelines and recommendations on mutation breeding for resistance to insects are given in an appendix

Trichoderma spp.: a biocontrol agent for sustainable management of plant diseases

International Nuclear Information System (INIS)

Naher, L.; Ismail, A.

2014-01-01

Trichoderma spp. are mainly asexual fungi that are present in all types of agricultural soils and also in decaying wood. The antagonistic activity of Trichoderma species showed that it is parasitic on many soil-borne and foliage pathogens. The fungus is also a decomposer of cellulosic waste materials. Recent discoveries show that the fungi not only act as biocontrol agents, but also stimulate plant resistance, and plant growth and development resulting in an increase in crop production. The biocontrol activity involving mycoparasitism, antibiotics and competition for nutrients, also induces defence responses or systemic resistance responses in plants. These responses are an important part of Trichoderma in biocontrol program. Currently, Trichoderma spp., is being used to control plant diseases in sustainable diseases management systems. This paper reviews the published information on Trichoderma spp., and its biocontrol activity in sustainable disease management programs. (author)

Metal resistance sequences and transgenic plants

Science.gov (United States)

Meagher, Richard Brian; Summers, Anne O.; Rugh, Clayton L.

1999-10-12

The present invention provides nucleic acid sequences encoding a metal ion resistance protein, which are expressible in plant cells. The metal resistance protein provides for the enzymatic reduction of metal ions including but not limited to divalent Cu, divalent mercury, trivalent gold, divalent cadmium, lead ions and monovalent silver ions. Transgenic plants which express these coding sequences exhibit increased resistance to metal ions in the environment as compared with plants which have not been so genetically modified. Transgenic plants with improved resistance to organometals including alkylmercury compounds, among others, are provided by the further inclusion of plant-expressible organometal lyase coding sequences, as specifically exemplified by the plant-expressible merB coding sequence. Furthermore, these transgenic plants which have been genetically modified to express the metal resistance coding sequences of the present invention can participate in the bioremediation of metal contamination via the enzymatic reduction of metal ions. Transgenic plants resistant to organometals can further mediate remediation of organic metal compounds, for example, alkylmetal compounds including but not limited to methyl mercury, methyl lead compounds, methyl cadmium and methyl arsenic compounds, in the environment by causing the freeing of mercuric or other metal ions and the reduction of the ionic mercury or other metal ions to the less toxic elemental mercury or other metals.

Tricking the guard: exploiting plant defense for disease susceptibility.

Science.gov (United States)

Lorang, J; Kidarsa, T; Bradford, C S; Gilbert, B; Curtis, M; Tzeng, S-C; Maier, C S; Wolpert, T J

2012-11-02

Typically, pathogens deploy virulence effectors to disable defense. Plants defeat effectors with resistance proteins that guard effector targets. We found that a pathogen exploits a resistance protein by activating it to confer susceptibility in Arabidopsis. The guard mechanism of plant defense is recapitulated by interactions among victorin (an effector produced by the necrotrophic fungus Cochliobolus victoriae), TRX-h5 (a defense-associated thioredoxin), and LOV1 (an Arabidopsis susceptibility protein). In LOV1's absence, victorin inhibits TRX-h5, resulting in compromised defense but not disease by C. victoriae. In LOV1's presence, victorin binding to TRX-h5 activates LOV1 and elicits a resistance-like response that confers disease susceptibility. We propose that victorin is, or mimics, a conventional pathogen virulence effector that was defeated by LOV1 and confers virulence to C. victoriae solely because it incites defense.

Enhanced resistance to Spodoptera litura in endophyte infected cauliflower plants.

Science.gov (United States)

Thakur, Abhinay; Kaur, Sanehdeep; Kaur, Amarjeet; Singh, Varinder

2013-04-01

Endophytic fungi, which live within host plant tissues without causing any visible symptom of disease, are important mediators of plant-herbivore interactions. These endophytes enhance resistance of host plant against insect herbivores mainly by productions of various alkaloid based defensive compounds in the plant tissue or through alterations of plant nutritional quality. Two endophytic fungi, i.e., Nigrospora sp. and Cladosporium sp., were isolated from Tinospora cordifolia (Thunb.) Miers, a traditional indian medicinal plant. Cauliflower (Brassica oleracea L.) plants were inoculated with these two endophytic fungi. The effect of endophyte infected and uninfected cauliflower plants were measured on the survival and development of Spodoptera litura (Fab.), a polyphagous pest. Endophyte infected cauliflower plants showed resistance to S. litura in the form of significant increase in larval and pupal mortality in both the fungi. Inhibitory effects of endophytic fungi also were observed on adult emergence, longevity, reproductive potential, as well as hatchability of eggs. Thus, it is concluded that antibiosis to S. litura could be imparted by artificial inoculation of endophytes and this could be used to develop alternative ecologically safe control strategies.

Advances and Challenges in Genomic Selection for Disease Resistance.

Science.gov (United States)

Poland, Jesse; Rutkoski, Jessica

2016-08-04

Breeding for disease resistance is a central focus of plant breeding programs, as any successful variety must have the complete package of high yield, disease resistance, agronomic performance, and end-use quality. With the need to accelerate the development of improved varieties, genomics-assisted breeding is becoming an important tool in breeding programs. With marker-assisted selection, there has been success in breeding for disease resistance; however, much of this work and research has focused on identifying, mapping, and selecting for major resistance genes that tend to be highly effective but vulnerable to breakdown with rapid changes in pathogen races. In contrast, breeding for minor-gene quantitative resistance tends to produce more durable varieties but is a more challenging breeding objective. As the genetic architecture of resistance shifts from single major R genes to a diffused architecture of many minor genes, the best approach for molecular breeding will shift from marker-assisted selection to genomic selection. Genomics-assisted breeding for quantitative resistance will therefore necessitate whole-genome prediction models and selection methodology as implemented for classical complex traits such as yield. Here, we examine multiple case studies testing whole-genome prediction models and genomic selection for disease resistance. In general, whole-genome models for disease resistance can produce prediction accuracy suitable for application in breeding. These models also largely outperform multiple linear regression as would be applied in marker-assisted selection. With the implementation of genomic selection for yield and other agronomic traits, whole-genome marker profiles will be available for the entire set of breeding lines, enabling genomic selection for disease at no additional direct cost. In this context, the scope of implementing genomics selection for disease resistance, and specifically for quantitative resistance and quarantined pathogens

Breeding of new variety Yangfumai 4 with high resistance to wheat yellow mosaic disease

International Nuclear Information System (INIS)

He Zhentian; Chen Xiulan; Zhang Rong; Wang Jianhua; Wang Jinrong; Liu Jian

2011-01-01

To control the infection of wheat yellow mosaic disease,new wheat variety with high-yield, disease-resistant was selected. Ningmai 9, which carries yellow mosaic disease resistant genes, was used as original material. Combination of conventional breeding technique and radiation methods, a new wheat variety Yangfumai 4 was developed during 1996-2007, and registered in 2008. The new wheat variety with high yield and resistance to yellow mosaic disease is suitable to plant in the Yangtze River region. (authors)

Mining the Genus Solanum for Increasing Disease Resistance

NARCIS (Netherlands)

Vossen, J.H.; Kwang-Ryong Jo,; Vosman, B.J.

2014-01-01

Plant Breeding is the art of selecting and discarding genetic material to achieve crop improvement. Favourable alleles resulting in quality improvement or disease resistance must be added, while unfavourable alleles must be removed. The source for novel alleles can be other varieties, landraces or

Systematic Analysis and Comparison of Nucleotide-Binding Site Disease Resistance Genes in a Diploid Cotton Gossypium raimondii

Science.gov (United States)

Wei, Hengling; Li, Wei; Sun, Xiwei; Zhu, Shuijin; Zhu, Jun

2013-01-01

Plant disease resistance genes are a key component of defending plants from a range of pathogens. The majority of these resistance genes belong to the super-family that harbors a Nucleotide-binding site (NBS). A number of studies have focused on NBS-encoding genes in disease resistant breeding programs for diverse plants. However, little information has been reported with an emphasis on systematic analysis and comparison of NBS-encoding genes in cotton. To fill this gap of knowledge, in this study, we identified and investigated the NBS-encoding resistance genes in cotton using the whole genome sequence information of Gossypium raimondii. Totally, 355 NBS-encoding resistance genes were identified. Analyses of the conserved motifs and structural diversity showed that the most two distinct features for these genes are the high proportion of non-regular NBS genes and the high diversity of N-termini domains. Analyses of the physical locations and duplications of NBS-encoding genes showed that gene duplication of disease resistance genes could play an important role in cotton by leading to an increase in the functional diversity of the cotton NBS-encoding genes. Analyses of phylogenetic comparisons indicated that, in cotton, the NBS-encoding genes with TIR domain not only have their own evolution pattern different from those of genes without TIR domain, but also have their own species-specific pattern that differs from those of TIR genes in other plants. Analyses of the correlation between disease resistance QTL and NBS-encoding resistance genes showed that there could be more than half of the disease resistance QTL associated to the NBS-encoding genes in cotton, which agrees with previous studies establishing that more than half of plant resistance genes are NBS-encoding genes. PMID:23936305

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.

The genetic variance of resistance in M3 lines of rice against leaf blight disease

International Nuclear Information System (INIS)

Mugiono

1979-01-01

Seeds of Pelita I/1 rice variety were irradiated with 20, 30, 40 and 50 krad of gamma rays from a 60 Co source. Plants of M 3 lines were inoculated with bacterial leaf blight, Xanthomonas oryzae (Uzeda and Ishiyama) Downson, using clipping method. The coefficient of genetic variability of resistance against leaf blight disease increased with increasing dose. Highly significant difference in the genetic variance of resistance were found between the treated samples and the control. Dose of 20 krad gave good probability for selection of plants resistant against leaf blight disease. (author)

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

Evolution of insect pest and disease resistant, high-yielding and improved quality varieties of cotton by use of ionizing radiation. Part of a coordinated programme on the use of induced mutations for disease resistance in crop plants

International Nuclear Information System (INIS)

Vasti, S.M.

1981-06-01

Disease resistant, high yielding and higher quality cotton varieties were developed. 42 interspecific hybrid progenies of earlier crosses between Gossypium barbadense and Gossypium tomentosum or Gossypium barbadense and Gossypium hirsutum were included. Out of these, 22 progenies in F 3 generation were irradiated by gamma radiation doses of 20 and 25 kR. A list is given of interspecific hybrid progenies, as are the lists of boll rot susceptible and resistant plants in the irradiated and non-irradiated populations and/or successful crosses made between 1977 and 1978

Induced mutations for disease resistance in wheat and barley

International Nuclear Information System (INIS)

Hanis, M.; Hanisova, A.; Knytl, V.; Cerny, J.; Benc, S.

1977-01-01

The induction of mutations in cultivars of wheat (Triticum aestivum), barley (Hordeum vulgare), and field beans (Phaseolus vulgaris) has been part of the breeding programme at the Plant Breeding Station at Stupice since 1960. A total of 26 cultivars or selections of winter wheat, 4 cultivars or selections of spring wheat, 2 cultivars of field beans, and 43 selections of spring barley have been treated since 1960. A total of 140 mutant lines of wheat and 37 mutant lines of barley with improved disease resistance of a race-specific type have been obtained. Several mutation programme derived cultivars have been registered in Czechoslovakia (''Diamant'', ''Ametyst'', ''Favorit'', ''Hana'', ''Rapid'', and ''Atlas'' in barley, and ''Alfa'' in field beans), but none of them is a mutation for disease resistance. A series of mutants have been used in crossing programmes. Approaches to improve the efficiency of mutation breeding for disease resistance are suggested. (author)

Molecular mapping of qBK1 WD , a major QTL for bakanae disease resistance in rice.

Science.gov (United States)

Lee, Sais-Beul; Hur, Yeon-Jae; Cho, Jun-Hyeon; Lee, Jong-Hee; Kim, Tae-Heon; Cho, Soo-Min; Song, You-Chun; Seo, Young-Su; Lee, Jungkwan; Kim, Tae-Sung; Park, Yong-Jin; Oh, Myung-Kyu; Park, Dong-Soo

2018-01-10

Bakanae or foot rot disease is a prominent disease of rice caused by Gibberella fujikuroi. This disease may infect rice plants from the pre-emergence stage to the mature stage. In recent years, raising rice seedlings in seed boxes for mechanical transplanting has increased the incidence of many seedling diseases; only a few rice varieties have been reported to exhibit resistance to bakanae disease. In this study, we attempted to identify quantitative trait loci (QTLs) conferring bakanae disease resistance from the highly resistant japonica variety Wonseadaesoo. A primary QTL study using the genotypes/phenotypes of the recombinant inbred lines (RILs) indicated that the locus qBK1 WD conferring resistance to bakanae disease from Wonseadaesoo was located in a 1.59 Mb interval delimited on the physical map between chr01_13542347 (13.54 Mb) and chr01_15132528 (15.13 Mb). The log of odds (LOD) score of qBK1 WD was 8.29, accounting for 20.2% of the total phenotypic variation. We further identified a gene pyramiding effect of two QTLs, qBK WD and previously developed qBK1. The mean proportion of healthy plant for 31 F 4 RILs that had no resistance genes was 35.3%, which was similar to that of the susceptible check variety Ilpum. The proportion of healthy plants for the lines with only qBK WD or qBK1 was 66.1% and 55.5%, respectively, which was significantly higher than that of the lines without resistance genes and that of Ilpum. The mean proportion of the healthy plant for 15 F 4 RILs harboring both qBK WD and qBK1 was 80.2%, which was significantly higher than that of the lines with only qBK WD or qBK1. Introducing qBK WD or pyramiding the QTLs qBK WD and qBK1 could provide effective tools for breeding rice with bakanae disease resistance. To our knowledge, this is the first report on a gene pyramiding effect that provides higher resistance against bakanae disease.

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

β-Amino-n-butyric Acid Regulates Seedling Growth and Disease Resistance of Kimchi Cabbage

Directory of Open Access Journals (Sweden)

Yeong Chae Kim

2013-09-01

Full Text Available Non-protein amino acid, β-amino-n-butyric acid (BABA, has been involved in diverse physiological processes including seedling growth, stress tolerance and disease resistance of many plant species. In the current study, treatment of kimchi cabbage seedlings with BABA significantly reduced primary root elongation and cotyledon development in a dose-dependent manner, which adverse effects were similar to the plant response to exogenous abscisic acid (ABA application. BABA was synergistically contributing ABA-induced growth arrest during the early seedling development. Kimchi cabbage leaves were highly damaged and seedling growth was delayed by foliar spraying with high concentrations of BABA (10 to 20 mM. BABA played roles differentially in in vitro fungal conidial germination, mycelial growth and conidation of necrotroph Alternaria brassicicola causing black spot disease and hemibiotroph Colletotrichum higginsianum causing anthracnose. Pretreatment with BABA conferred induced resistance of the kimchi cabbage against challenges by the two different classes of fungal pathogens in a dose-dependent manner. These results suggest that BABA is involved in plant development, fungal development as well as induced fungal disease resistance of kimchi cabbage plant.

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.

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...

Resistance mechanisms to plant viruses: an overview

NARCIS (Netherlands)

Goldbach, R.W.; Bucher, E.C.; Prins, A.H.

2003-01-01

To obtain virus-resistant host plants, a range of operational strategies can be followed nowadays. While for decades plant breeders have been able to introduce natural resistance genes in susceptible genotypes without knowing precisely what these resistance traits were, currently a growing number of

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

Differential disease resistance response in the barley necrotic mutant nec1

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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

Plant Translation Factors and Virus Resistance

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Hélène Sanfaçon

2015-06-01

Full Text Available Plant viruses recruit cellular translation factors not only to translate their viral RNAs but also to regulate their replication and potentiate their local and systemic movement. Because of the virus dependence on cellular translation factors, it is perhaps not surprising that many natural plant recessive resistance genes have been mapped to mutations of translation initiation factors eIF4E and eIF4G or their isoforms, eIFiso4E and eIFiso4G. The partial functional redundancy of these isoforms allows specific mutation or knock-down of one isoform to provide virus resistance without hindering the general health of the plant. New possible targets for antiviral strategies have also been identified following the characterization of other plant translation factors (eIF4A-like helicases, eIF3, eEF1A and eEF1B that specifically interact with viral RNAs and proteins and regulate various aspects of the infection cycle. Emerging evidence that translation repression operates as an alternative antiviral RNA silencing mechanism is also discussed. Understanding the mechanisms that control the development of natural viral resistance and the emergence of virulent isolates in response to these plant defense responses will provide the basis for the selection of new sources of resistance and for the intelligent design of engineered resistance that is broad-spectrum and durable.

Amazonian plant crude extract screening for activity against multidrug-resistant bacteria.

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Correia, A F; Segovia, J F O; Gonçalves, M C A; de Oliveira, V L; Silveira, D; Carvalho, J C T; Kanzaki, L I B

2008-01-01

Antimicrobial resistance is a subject of great concern in public health and also in the designing of strategies for current therapeutic protocols all over the world. New drugs, including those necessary for a reserve armamentarium and exhibiting less side effects deserve special attention. In rural areas, particularly in Brazil, a huge number of natural products, in different artisanal preparations, mainly from plants, have been used by traditional populations to cure diseases. Despite some of these plants have been studied, many of them are awaiting to have their compounds chemically characterized and investigated their pharmacodynamics properties. Further, as well known, the environment plays a crucial role in the metabolism of these plants, yielding different and varied molecular complexes depending on the period of collection, climate conditions, kind of soil and also the plant speciation. In this report, ethanol crude extract of 10 different botanical specimens from the Amazon region of Brazil, in the Amapa State, were screened for antibacterial activity of 7 clinical resistant microorganisms utilizing as control ATCC bacterial species by the Kirby-Bauer method. Plant extracts of Geissospermum argenteum, Uncaria guianensis, Brosimum acutifolium, Copaifera reticulate, Licania macrophylla, Ptycopetalum olacoides and Dalbergia subcymosa yielded activity against Staphylococcus aureus and Pseudomonas aeruginosa, both multidrug resistant, and Staphylococcus aureus ATCC strain.

Fungal Biofilms: Targets for the Development of Novel Strategies in Plant Disease Management.

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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.

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

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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...

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

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Kim, Ji-Seong; Lee, Jeongeun; Lee, Chan-Hui; Woo, Su Young; Kang, Hoduck; Seo, Sang-Gyu; Kim, Sun-Hyung

2015-06-01

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.

Editing plants for virus resistance using CRISPR-Cas.

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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).

Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

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Xuepeng eFu

2015-09-01

Full Text Available Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae. To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related

Cytotoxicity of South-African medicinal plants towards sensitive and multidrug-resistant cancer cells.

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Saeed, Mohamed E M; Meyer, Marion; Hussein, Ahmed; Efferth, Thomas

2016-06-20

Traditional medicine plays a major role for primary health care worldwide. Cancer belongs to the leading disease burden in industrialized and developing countries. Successful cancer therapy is hampered by the development of resistance towards established anticancer drugs. In the present study, we investigated the cytotoxicity of 29 extracts from 26 medicinal plants of South-Africa against leukemia cell lines, most of which are used traditionally to treat cancer and related symptoms. We have investigated the plant extracts for their cytotoxic activity towards drug-sensitive parental CCRF-CEM leukemia cells and their multidrug-resistant P-glycoprotein-overexpressing subline, CEM/ADR5000 by means of the resazurin assay. A panel of 60 NCI tumor cell lines have been investigated for correlations between selected phytochemicals from medicinal plants and the expression of resistance-conferring genes (ABC-transporters, oncogenes, tumor suppressor genes). Seven extracts inhibited both cell lines (Acokanthera oppositifolia, Hypoestes aristata, Laurus nobilis, Leonotis leonurus, Plectranthus barbatus, Plectranthus ciliates, Salvia apiana). CEM/ADR5000 cells exhibited a low degree of cross-resistance (3.35-fold) towards the L. leonurus extract, while no cross-resistance was observed to other plant extracts, although CEM/ADR5000 cells were highly resistant to clinically established drugs. The log10IC50 values for two out of 14 selected phytochemicals from these plants (acovenoside A and ouabain) of 60 tumor cell lines were correlated to the expression of ABC-transporters (ABCB1, ABCB5, ABCC1, ABCG2), oncogenes (EGFR, RAS) and tumor suppressors (TP53). Sensitivity or resistance of the cell lines were not statistically associated with the expression of these genes, indicating that multidrug-resistant, refractory tumors expressing these genes may still respond to acovenoside A and ouabain. The bioactivity of South African medicinal plants may represent a basis for the development

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

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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

Omics Approach to Identify Factors Involved in Brassica Disease Resistance.

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Francisco, Marta; Soengas, Pilar; Velasco, Pablo; Bhadauria, Vijai; Cartea, Maria E; Rodríguez, Victor M

2016-01-01

Understanding plant's defense mechanisms and their response to biotic stresses is of fundamental meaning for the development of resistant crop varieties and more productive agriculture. The Brassica genus involves a large variety of economically important species and cultivars used as vegetable source, oilseeds, forage and ornamental. Damage caused by pathogens attack affects negatively various aspects of plant growth, development, and crop productivity. Over the last few decades, advances in plant physiology, genetics, and molecular biology have greatly improved our understanding of plant responses to biotic stress conditions. In this regard, various 'omics' technologies enable qualitative and quantitative monitoring of the abundance of various biological molecules in a high-throughput manner, and thus allow determination of their variation between different biological states on a genomic scale. In this review, we have described advances in 'omic' tools (genomics, transcriptomics, proteomics and metabolomics) in the view of conventional and modern approaches being used to elucidate the molecular mechanisms that underlie Brassica disease resistance.

fungal disease resistance in vicia faba in relation to water stress and gamma irradiation

International Nuclear Information System (INIS)

Ahmed, B.M.M.

2001-01-01

Induced systemic resistance (Isr), as a recent strategy, achieving biological control of plant disease through initiation to form natural antibiotic compounds, phytoalexin, that considered to be involved in the defense mechanism of plant to potential pathogen. Also, phytoalexin formed by leguminosae in response to infection play an extremely role in disease resistance. Indeed, wyerone acid (C 14 H 12 O 4 ) has been clearfield as a phytoalexin formed by Vicia faba in response to infection stress. Therefore, the present study was outlined to clearify the feasibility to biocontrol of checolate spot disease caused by Botrytis fabae in faba bean, Vicia faba, plants under field condition. Pre. Sowing seed irradiated with low gamma ray were planted in: 1- Three pot experiments (salinity-Ni-Si) in complete randomized block design in three replicates. 2- Two field experiments in loam soil irrigated with river nile water (inducers-Isr)) in splite-plot design in three replicates. 3- Two field experiments in sandy soil irrigated with two saline water from 2 shallow-wells (inducers-Isr) in split-split plot design in three replicates

Plant age, communication, and resistance to herbivores: young sagebrush plants are better emitters and receivers.

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Shiojiri, Kaori; Karban, Richard

2006-08-01

Plants progress through a series of distinct stages during development, although the role of plant ontogeny in their defenses against herbivores is poorly understood. Recent work indicates that many plants activate systemic induced resistance after herbivore attack, although the relationship between resistance and ontogeny has not been a focus of this work. In addition, for sagebrush and a few other species, individuals near neighbors that experience simulated herbivory become more resistant to subsequent attack. Volatile, airborne cues are required for both systemic induced resistance among branches and for communication among individuals. We conducted experiments in stands of sagebrush of mixed ages to determine effects of plant age on volatile signaling between branches and individuals. Young and old control plants did not differ in levels of chewing damage that they experienced. Systemic induced resistance among branches was only observed for young plants. Young plants showed strong evidence of systemic resistance only if airflow was permitted among branches; plants with only vascular connections showed no systemic resistance. We also found evidence for volatile communication between individuals. For airborne communication, young plants were more effective emitters of cues as well as more responsive receivers of volatile cues.

Methyl esterification of pectin plays a role during plant-pathogen interactions and affects plant resistance to diseases.

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Lionetti, Vincenzo; Cervone, Felice; Bellincampi, Daniela

2012-11-01

The cell wall is a complex structure mainly composed by a cellulose-hemicellulose network embedded in a cohesive pectin matrix. Pectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on both the physiological processes of the plants and their resistance to pathogens. PME activity displays a crucial role in the outcome of the plant-pathogen interactions by making pectin more susceptible to the action of the enzymes produced by the pathogens. This review focuses on the impact of pectin methyl esterification in plant-pathogen interactions and on the dynamic role of its alteration during pathogenesis. Copyright © 2012 Elsevier GmbH. All rights reserved.

Transgenic Strategies for Enhancement of Nematode Resistance in Plants

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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.

Mutant lines of currant tomato, valuable germplasm with multiple disease resistance

International Nuclear Information System (INIS)

Govorova, G.F.; Khrustaleva, V.V.; Shcherbakov, V.K.

1987-01-01

Studies were carried out for two years on eight mutant lines of currant tomato at the Krymsk Experimental Breeding Station of the N.I. Vavilov All-Union Scientific Research Institute of Plant-Growing (VIR). The station is situated in an area of commercial field tomato growing (Krasnodar region). The mutant lines of currant tomato (VIR specimen No. k-4053) were obtained through chronic gamma-irradiation. A disease resistance evaluation of the mutants was carried out for Verticillium wilt (Verticillium albo-atrum Rein. and Berth.), for black bacterial spotting (Xanthomonas vesicatoria Dows.), for tobacco mosaic virus Nicotiana 1 Smith), for streak virus (Nicotiana 1), for the combination TMV with X and Y potato viruses, for cucumber virus (Cucumis 1), and also for top rot. Fifty plants of each mutant line were evaluated and checks were made three times in each season. A comparison of the currant tomato mutants with the standard tomato varieties demonstrates the better resistance shown by the mutant germplasm to the main pathogens. The degree to which some currant tomato mutants were affected by Verticillium was lower than that of the most VerticiIlium-resistant samples of tomato evaluated between 1975 and 1981. The mutants of currant tomato should therefore be of interest as germplasm in breeding tomatoes for improved multiple disease resistance

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

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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

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

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Ignacimuthu, S; Ceasar, S Antony

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.

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

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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'.

Signaling requirements for Erwinia amylovora-induced disease resistance, callose deposition, and cell growth in the nonhost Arabidopsis thaliana

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Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The nonhost plant Arabidopsis serves as a powerful system to dissect mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found ...

Race-Specific Adult-Plant Resistance in Winter Wheat to Stripe Rust and Characterization of Pathogen Virulence Patterns.

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Milus, Eugene A; Moon, David E; Lee, Kevin D; Mason, R Esten

2015-08-01

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of wheat in the Great Plains and southeastern United States. Growing resistant cultivars is the preferred means for managing stripe rust, but new virulence in the pathogen population overcomes some of the resistance. The objectives of this study were to characterize the stripe rust resistance in contemporary soft and hard red winter wheat cultivars, to characterize the virulence of P. striiformis f. sp. tritici isolates based on the resistances found in the cultivars, and to determine wheat breeders' perceptions on the importance and methods for achieving stripe rust resistance. Seedlings of cultivars were susceptible to recent isolates, indicating they lacked effective all-stage resistance. However, adult-plants were resistant or susceptible depending on the isolate, indicating they had race-specific adult-plant resistance. Using isolates collected from 1990 to 2013, six major virulence patterns were identified on adult plants of twelve cultivars that were selected as adult-plant differentials. Race-specific adult-plant resistance appears to be the only effective type of resistance protecting wheat from stripe rust in eastern United States. Among wheat breeders, the importance of incorporating stripe rust resistance into cultivars ranged from high to low depending on the frequency of epidemics in their region, and most sources of stripe rust resistance were either unknown or already overcome by virulence in the pathogen population. Breeders with a high priority for stripe rust resistance made most of their selections based on adult-plant reactions in the field, whereas breeders with a low priority for resistance based selections on molecular markers for major all-stage resistance genes.

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

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Stout, Michael J

2013-06-01

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. © 2012 Institute of Zoology, Chinese Academy of Sciences.

Infection processes of xylem-colonizing pathogenic bacteria: possible explanations for the scarcity of qualitative disease resistance genes against them in crops.

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Bae, Chungyun; Han, Sang Wook; Song, Yu-Rim; Kim, Bo-Young; Lee, Hyung-Jin; Lee, Je-Min; Yeam, Inhwa; Heu, Sunggi; Oh, Chang-Sik

2015-07-01

Disease resistance against xylem-colonizing pathogenic bacteria in crops. Plant pathogenic bacteria cause destructive diseases in many commercially important crops. Among these bacteria, eight pathogens, Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, Erwinia amylovora, Pantoea stewartii subsp. stewartii, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. actinidiae, and Xylella fastidiosa, infect their host plants through different infection sites and paths and eventually colonize the xylem tissues of their host plants, resulting in wilting symptoms by blocking water flow or necrosis of xylem tissues. Noticeably, only a relatively small number of resistant cultivars in major crops against these vascular bacterial pathogens except X. oryzae pv. oryzae have been found or generated so far, although these pathogens threaten productivity of major crops. In this review, we summarize the lifestyles of major xylem-colonizing bacterial pathogens and then discuss the progress of current research on disease resistance controlled by qualitative disease resistance genes or quantitative trait loci against them. Finally, we propose infection processes of xylem-colonizing bacterial pathogens as one of possible reasons for why so few qualitative disease resistance genes against these pathogens have been developed or identified so far in crops.

Antimicrobial Resistance and the Alternative Resources with Special Emphasis on Plant-Based Antimicrobials—A Review

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Harish Chandra

2017-04-01

Full Text Available Indiscriminate and irrational use of antibiotics has created an unprecedented challenge for human civilization due to microbe’s development of antimicrobial resistance. It is difficult to treat bacterial infection due to bacteria’s ability to develop resistance against antimicrobial agents. Antimicrobial agents are categorized according to their mechanism of action, i.e., interference with cell wall synthesis, DNA and RNA synthesis, lysis of the bacterial membrane, inhibition of protein synthesis, inhibition of metabolic pathways, etc. Bacteria may become resistant by antibiotic inactivation, target modification, efflux pump and plasmidic efflux. Currently, the clinically available treatment is not effective against the antibiotic resistance developed by some bacterial species. However, plant-based antimicrobials have immense potential to combat bacterial, fungal, protozoal and viral diseases without any known side effects. Such plant metabolites include quinines, alkaloids, lectins, polypeptides, flavones, flavonoids, flavonols, coumarin, terpenoids, essential oils and tannins. The present review focuses on antibiotic resistance, the resistance mechanism in bacteria against antibiotics and the role of plant-active secondary metabolites against microorganisms, which might be useful as an alternative and effective strategy to break the resistance among microbes.

Mutant of Japanese pear resistant to Black Spot Disease

International Nuclear Information System (INIS)

Sanada, T.; Nishida, T.; Ikeda, F.

1987-01-01

Full text: Nijisseike is one of the leading cultivars of Japanese pear (Pyrus serotinea Rehd.), but susceptible to black spot disease. Farmers try to prevent this disease by wrapping the fruit with a paper bag and by repeated spraying of fungicides. The disease is caused by a Japanese pear pathotype of Alternaria alternata (Fr.) Keissler. Susceptibility is controlled by a single dominant gene. In 1962, grafted trees of this cultivar were planted at a distance between 53 and 93 m from the 60 Co source in the gamma-field (daily dose 15-4 rad). One branch on a tree planted at 53 m was detected as resistant in 1981. Under field conditions, black spots were observed on many fruits and leaves of the original trees by natural infection in early July, however, they were not observed on the mutant. To examine the resistance of the mutant, artificial inoculations were made using spores of the pathogen and the host specific toxin produced by germinating spores. When some drops of the spore suspension are placed on leaves, the formation of black spots depends upon the leaf age. In a resistant cv. as Chojuro, black spot symptoms are formed only when inoculated on young leaves. An intermediate reaction was observed in the mutant, whereas the original Nijisseiki showed severe symptoms. When inoculation was made on matured fruit skins, no black spot was formed on the mutant just like on the resistant cv. Chojuro, while many small black spots were formed and grew into large spots overlapping each other on the susceptible cv. Nijisseiki. In case of the crude toxin inoculation (4-0.04 ppm) of cv. Nijisseiki black spots were formed on the surface of the susceptible fruit skin, and necrotic lesions at the cut end of detached small pieces of leaves, although reaction on fruit skins was weaker compared with inoculation by spores. However, no symptoms were observed from the toxin application on the mutant and the resistant cv. Chojuro. That the resistance of the mutant is classified as

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.

Frost resistance of alpine woody plants

Directory of Open Access Journals (Sweden)

Gilbert eNeuner

2014-12-01

Full Text Available 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.

Chloroplast-expressed MSI-99 in tobacco improves disease resistance and displays inhibitory effect against rice blast fungus.

Science.gov (United States)

Wang, Yun-Peng; Wei, Zheng-Yi; Zhang, Yu-Ying; Lin, Chun-Jing; Zhong, Xiao-Fang; Wang, Yue-Lin; Ma, Jing-Yong; Ma, Jian; Xing, Shao-Chen

2015-03-02

Rice blast is a major destructive fungal disease that poses a serious threat to rice production and the improvement of blast resistance is critical to rice breeding. The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. Transformed plants were obtained and verified to be homoplastomic by PCR and Southern hybridization. In planta assays demonstrated that the transgenic tobacco plants displayed an enhanced resistance to the fungal disease. The evaluation of the antimicrobial activity revealed that the crude protein extracts from the transgenic plants manifested an antimicrobial activity against E. coli, even after incubation at 120 °C for 20 min, indicating significant heat stability of MSI-99. More importantly, the MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

Chloroplast-Expressed MSI-99 in Tobacco Improves Disease Resistance and Displays Inhibitory Effect against Rice Blast Fungus

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Yun-Peng Wang

2015-03-01

Full Text Available Rice blast is a major destructive fungal disease that poses a serious threat to rice production and the improvement of blast resistance is critical to rice breeding. The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. Transformed plants were obtained and verified to be homoplastomic by PCR and Southern hybridization. In planta assays demonstrated that the transgenic tobacco plants displayed an enhanced resistance to the fungal disease. The evaluation of the antimicrobial activity revealed that the crude protein extracts from the transgenic plants manifested an antimicrobial activity against E. coli, even after incubation at 120 °C for 20 min, indicating significant heat stability of MSI-99. More importantly, the MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

Plant Essential Oils Used Against Some Bee Diseases

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Hidayet Tutun

2018-02-01

Full Text Available The most common honey bee diseases are American foulbrood (AFB caused by the bacterium Paenibacillus larvae, Chalkbrood caused by fungus Ascosphaera apis and diseases caused by parasitic mites such as Acarapis woodi, Varroa destructor. These diseases and pests not only cause economic loss but also cause ecological problems related to the role of honey bees, as the most important pollinators on Earth. Synthetic acaricides and antibiotics are used to keep the diseases and mites in control. Use of the drugs lead to the development of drug-resistant organisms, detrimental effect on non-target organisms and the residue problem in bee products. For this reasons, the need for alternative control methods has become compulsory in recent years. It has been known that some plant oils used widely in perfumery and food industry for flavor and smell have been used as repellent to certain insects, bactericide and fungicide. Therefore, intensive studies have been carried out on plants with anti-mites, antibacterial and antifungal potentials and these studies are still going on. Recently, studies in this area have shown that essential oils of plants such as thyme, cloves, mint, lemon grass, cinnamon, grapefruit, rosemary, marigold, are lethal to some mites, bacteria and fungi. In addition, it has been reported that some components, isolated from these plants such as sanguinarine, thymoquinone, capsaicin, carvacrol, citral, eugenol, thymol, show these effects on the organisms. As a result, in countries rich in biodiversity due to endemic plant species, the essential oils used in control of these diseases should be favored instead of or in combination with conventional drugs in integrated the disease management programs because of the lack of harmful effects of essential oils on non-target organisms and environment.

The improvement of rice varieties for major pest and diseases resistance

International Nuclear Information System (INIS)

Sahi, I.; Silitonga, T.S.

1988-01-01

Since 1971, the rice breeding program in Indonesia has developed on intensive program to improve varieties for yield potential, resistancy to major pests and diseases, early maturity good grain and eating quality. In recent years, the attacks of insects and diseases are very severe in rice cultivation in Asia. Much of the losses were due to acontinuous planting or certain varieties. Between 1966 and 1973 tungro occured in epidemic proportions on separate occasions in Indonesia, Thailand, Nort East India, Bangladesh, and Philippine. Since 1973, investation of brown planthopper and green leafhopper several damaged rice crop in most parts of Indonesia. Presently, rice improvement are directed to develop high yielding rice varieties that are resistant to brown planthopper, ragged stunt virus, blast, green leafhopper, and gallmidge. Screening for pests and diseases are conducted in the laboratory as well as in the field. The adoption of those improved varieties by farmers has contributed greatly in our efforts to attain self sufficiency in rice production in Indonesia. GH 147 -M-40 krad-Pn-89 (irradiated Barito) showed resistant to brown planthopper biotype 1 and 2 and moderately resistant to biotype 3. Napa 40 krad-St-12 has resistant reaction to blast. (authors). 4 refs, 8 tabs

Appraisal of wheat germplasm for adult plant resistance against stripe rust

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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

Resistance of solanum species to phytophthora infestans evaluated in the detached-leaf and whole-plant assays

International Nuclear Information System (INIS)

Akhtar, K.P.; Saleem, M.Y.; Asghar, M.

2012-01-01

The reaction of 82 tomato genotypes belonging to 8 Solanum and a Lycopersicon species against Phytophthora infestans causing late blight was determined using detached-leaf and whole-plant assays. None of the test genotypes was immune or highly resistant. Of the 82 commercial and wild genotypes only TMS-2 (male-sterile and characterized by indeterminate growth) belonging to Lycopersicon esculentum was resistant with severity index of 2.4 in the detached-leaf assay on 0-5 scale (where 5 was highly susceptible) and percent disease index (%DI) of 23.3% under the whole-plant assay. Among the remaining genotypes, 41 were susceptible and 40 were highly susceptible under the detached-leaf assay, while 18 were susceptible and 63 were highly susceptible under the whole-plant assay. However, there was a significant difference in %DI for genotypes under the whole-plant assay. The response of whole-plants to inoculation with P. infestans in the detached-leaf assay was similar in all cases. The overall screening results indicate that TMS-2 is a good source of resistance and it can be useful for the development of tomato hybrid cultivars resistant to late blight. (author)

Plant responses to plant growth-promoting rhizobacteria

NARCIS (Netherlands)

Loon, L.C. van

2007-01-01

Non-pathogenic soilborne microorganisms can promote plant growth, as well as suppress diseases. Plant growth promotion is taken to result from improved nutrient acquisition or hormonal stimulation. Disease suppression can occur through microbial antagonism or induction of resistance in the plant.

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.

Induction of Xa10-like Genes in Rice Cultivar Nipponbare Confers Disease Resistance to Rice Bacterial Blight.

Science.gov (United States)

Wang, Jun; Tian, Dongsheng; Gu, Keyu; Yang, Xiaobei; Wang, Lanlan; Zeng, Xuan; Yin, Zhongchao

2017-06-01

Bacterial blight of rice, caused by Xanthomonas oryzae pv. oryzae, is one of the most destructive bacterial diseases throughout the major rice-growing regions in the world. The rice disease resistance (R) gene Xa10 confers race-specific disease resistance to X. oryzae pv. oryzae strains that deliver the corresponding transcription activator-like (TAL) effector AvrXa10. Upon bacterial infection, AvrXa10 binds specifically to the effector binding element in the promoter of the R gene and activates its expression. Xa10 encodes an executor R protein that triggers hypersensitive response and activates disease resistance. 'Nipponbare' rice carries two Xa10-like genes in its genome, of which one is the susceptible allele of the Xa23 gene, a Xa10-like TAL effector-dependent executor R gene isolated recently from 'CBB23' rice. However, the function of the two Xa10-like genes in disease resistance to X. oryzae pv. oryzae strains has not been investigated. Here, we designated the two Xa10-like genes as Xa10-Ni and Xa23-Ni and characterized their function for disease resistance to rice bacterial blight. Both Xa10-Ni and Xa23-Ni provided disease resistance to X. oryzae pv. oryzae strains that deliver the matching artificially designed TAL effectors (dTALE). Transgenic rice plants containing Xa10-Ni and Xa23-Ni under the Xa10 promoter provided specific disease resistance to X. oryzae pv. oryzae strains that deliver AvrXa10. Xa10-Ni and Xa23-Ni knock-out mutants abolished dTALE-dependent disease resistance to X. oryzae pv. oryzae. Heterologous expression of Xa10-Ni and Xa23-Ni in Nicotiana benthamiana triggered cell death. The 19-amino-acid residues at the N-terminal regions of XA10 or XA10-Ni are dispensable for their function in inducing cell death in N. benthamiana and the C-terminal regions of XA10, XA10-Ni, and XA23-Ni are interchangeable among each other without affecting their function. Like XA10, both XA10-Ni and XA23-Ni locate to the endoplasmic reticulum (ER) membrane

Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

Directory of Open Access Journals (Sweden)

Mari Narusaka

Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

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 ...

Plant-Derived Antimicrobials: Insights into Mitigation of Antimicrobial Resistance

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Shun-Kai Yang

2018-07-01

Full Text Available Antibiotic resistance had first been reported not long after the discovery of the first antibiotic and has remained a major public health issue ever since. Challenges are constantly encountered during the mitigation process of antibiotic resistance in the clinical setting; especially with the emergence of the formidable superbug, a bacteria with multiple resistance towards different antibiotics; this resulted in the term multidrug resistant (MDR bacteria. This rapid evolution of the resistance phenomenon has propelled researchers to continuously uncover new antimicrobial agents in a bid to hopefully, downplay the rate of evolution despite a drying pipeline. Recently, there has been a paradigm shift in the mining of potential antimicrobials; in the past, targets for drug discovery were from microorganisms and at current, the focus has moved onto plants, this is mainly due to the beneficial attributes that plants are able to confer over that of microorganisms. This review will briefly discuss antibiotic resistance mechanisms employed by resistant bacteria followed by a detailed expository regarding the use of secondary metabolites from plants as a potential solution to the MDR pathogen. Finally, future prospects recommending enhancements to the usage of plant secondary metabolites to directly target antibiotic resistant pathogens will be discussed.

Production of Basella plants resistant to rust by irradiation of seeds and vegetative tissue

International Nuclear Information System (INIS)

Makambila, C.

1997-01-01

Basella is classified in the family Chenopodiaceae or Basellaceae. Also known as African spinach, this plant is consumed in Central Africa and several other African countries. There are two types of varieties grown in Congo: i. a local variety characterized by red leaves and stalks in which the principal way of propagation is from cuttings; ii. a group of varieties which have green or purple leaves and stalks. These varieties are called Basella alba and Basella rubra. These varieties have sexual reproduction. Among the two groups of varieties, the local variety is propagated vegetatively but is resistant to rust, while varieties with green leaves or with purple leaves (B. alba and B. rubra) that are propagated from seed are susceptible to rust. Since hybrid cannot be made by conventional crossing, the following procedures have been adopted to produce plants with disease tolerance: 1. production of resistant variants by irradiation of Basella alba seeds with Cesium 137; 2. production of resistant variants by irradiation of vegetative tissues obtained by culture of meristematic cells of B alba; and 3. obtaining resistant plants through somaclonal variation. 1 tab

Production of Basella plants resistant to rust by irradiation of seeds and vegetative tissue

Energy Technology Data Exchange (ETDEWEB)

Makambila, C [Laboratory of Phytopathology, Faculty of Sciences, Univ. of Brazzaville, Brazzaville (Congo)

1997-12-01

Basella is classified in the family Chenopodiaceae or Basellaceae. Also known as African spinach, this plant is consumed in Central Africa and several other African countries. There are two types of varieties grown in Congo: i. a local variety characterized by red leaves and stalks in which the principal way of propagation is from cuttings; ii. a group of varieties which have green or purple leaves and stalks. These varieties are called Basella alba and Basella rubra. These varieties have sexual reproduction. Among the two groups of varieties, the local variety is propagated vegetatively but is resistant to rust, while varieties with green leaves or with purple leaves (B. alba and B. rubra) that are propagated from seed are susceptible to rust. Since hybrid cannot be made by conventional crossing, the following procedures have been adopted to produce plants with disease tolerance: 1. production of resistant variants by irradiation of Basella alba seeds with Cesium 137; 2. production of resistant variants by irradiation of vegetative tissues obtained by culture of meristematic cells of B alba; and 3. obtaining resistant plants through somaclonal variation. 1 tab.

Resistance to Powdery Mildews

DEFF Research Database (Denmark)

Siwoszek, Agnieszka Izabela

in majority of them. Resistance to barley powdery mildew in the field is controlled by use of resistant varieties in a combination with fungicides. Early disease management is crucial for effective control. Yet, the pathogen commonly develops fungicide resistance due to simple point mutations. Several studies...... protection. In the present study, I provide an overview of the current knowledge about plant pathogens and plant disease resistance. I use Arabidopsis as a model to investigate the mechanism of non-host resistance, presumed to be the most durable and broad-spectrum form of resistance. I attempt to determine...

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.

Sources of resistance in chickpea (cicer arietinum l.) land races against ascochyta rabiei causal agent of ascochyta blight disease

International Nuclear Information System (INIS)

Duzdemir, O.; Selvi, B.; Yanar, Y.

2014-01-01

Ascochyta blight disease, caused by the fungus Ascochyta rabiei, is a major yield limiting factor of chickpea in Turkey and around the world. This study was conducted to identify sources of genetic resistance against chickpea blight caused by Ascochyta rabiei. For this purpose, 68 chickpea land races of different origins were evaluated in both field and growth chamber conditions during 2008-2009 growing seassons. Two standard cultivars were used as a reference, Inci (resistant) and Canitez (susceptible). Disease severity scoring was conducted on a 1-9 rating scale 21 days after inoculation in growth chamber test and at flowering and pot filling stages in field tests. Analysis of variance (ANOVA) test showed a significant difference among the chickpea landraces in ascochyta blight resistance at p<0.05. None of the chickpea land races was highly resistant to the pathogen in growth chamber and field conditions. Only two landraces (10A and 28B) were moderately resistant to the disease. Some of the landraces resulted in a particular plant to exhibit no disease symptoms, indicating that the variation within chickpea land races was high. Therefore, seeds of this plant were harvested separately and preserved for further evaluations. (author)

Functional markers based molecular characterization and cloning of resistance gene analogs encoding NBS-LRR disease resistance proteins in finger millet (Eleusine coracana).

Science.gov (United States)

Panwar, Preety; Jha, Anand Kumar; Pandey, P K; Gupta, Arun K; Kumar, Anil

2011-06-01

Magnaporthe grisea, the blast fungus is one of the main pathological threats to finger millet crop worldwide. A systematic search for the blast resistance gene analogs was carried out, using functional molecular markers. Three-fourths of the recognition-dependent disease resistance genes (R-genes) identified in plants encodes nucleotide binding site (NBS) leucine-rich repeat (LRR) proteins. NBS-LRR homologs have only been isolated on a limited scale from Eleusine coracana. Genomic DNA sequences sharing homology with NBS region of resistance gene analogs were isolated and characterized from resistant genotypes of finger millet using PCR based approach with primers designed from conserved regions of NBS domain. Attempts were made to identify molecular markers linked to the resistance gene and to differentiate the resistant bulk from the susceptible bulk. A total of 9 NBS-LRR and 11 EST-SSR markers generated 75.6 and 73.5% polymorphism respectively amongst 73 finger millet genotypes. NBS-5, NBS-9, NBS-3 and EST-SSR-04 markers showed a clear polymorphism which differentiated resistant genotypes from susceptible genotypes. By comparing the banding pattern of different resistant and susceptible genotypes, five DNA amplifications of NBS and EST-SSR primers (NBS-05(504,) NBS-09(711), NBS-07(688), NBS-03(509) and EST-SSR-04(241)) were identified as markers for the blast resistance in resistant genotypes. Principal coordinate plot and UPGMA analysis formed similar groups of the genotypes and placed most of the resistant genotypes together showing a high level of genetic relatedness and the susceptible genotypes were placed in different groups on the basis of differential disease score. Our results provided a clue for the cloning of finger millet blast resistance gene analogs which not only facilitate the process of plant breeding but also molecular characterization of blast resistance gene analogs from Eleusine coracana.

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

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. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an ec...

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.

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.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Within plant resistance to water flow in tomato and sweet melons ...

African Journals Online (AJOL)

Efficient water resource management in relation to water use and crop yields is premised on the knowledge of plant resistance to water flow. However, such studies are limited and for most crops, the within plant resistance to water flow remains largely unknown. In this study, within plant resistance to water transport ...

Development of a Simple and Effective Bioassay Method to Evaluate Resistance of Watermelon Plants to Fusarium oxysporum f. sp. niveum

Directory of Open Access Journals (Sweden)

Eun Ju Jo

2017-06-01

Full Text Available Root-dipping inoculation method has been widely used to determine the resistance of watermelon to Fusarium oxysporum f. sp. niveum causing Fusarium wilt. Although this method leads to the precise results of plant disease responses, more rapid and efficient assay methods have been still required because the root-dipping inoculation method is labor-intensive and time-consuming. In this study, we established a simple and effective bioassay method based on the comparison of various inoculation methods and growth conditions. To develop the system, the occurrence of Fusarium wilt on four resistant and susceptible cultivars was investigated by four different inoculation methods, root-dipping, scalpel, tip and soil-drenching methods. Of these inoculation methods, scalpel method resulted in clear plant disease resistance responses with the simplicity. With the use of scalpel method, we also explored the disease development of the cultivars depending on inoculum concentration, growth stage of seedlings, and incubation temperature after inoculation. Furthermore, we found that the resistance degrees of 23 cultivars derived by scalpel inoculation method were similar to the results by root-dipping method established previously.

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.

Relationship between the shoot characteristics and plant resistance to vascular-streak dieback on cocoa

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Agung Wahyu Soesilo

2014-12-01

Full Text Available Vascular-streak dieback (Oncobasidium theobromae is a serious disease on cocoa damaging the vegetative tissue especially on the branches and leaves. This research was aimed to identify the relationship between characteristics of sprouting ability and VSD resistance to confirm the response of cocoa to pruning treatment on VSD control and developing criteria for selection. Trial was carried out at Kaliwining Experimental Station of ICCRI, a VSD-endemic area by using 668 plants of hybrid populayion which were derivated from intercrossing among seven clones performing different response to VSD. The resistance was evaluated by scoring the plant damage with the scale of 0-6 on drought season in the year of 2009 and 2011. The characteristics of sprouting ability was assessed by recording the pruned trees for the variables of the number of re-growth shoot, shoot height, number of new shoot per pruned branches, shoot diameter and number of leaves per shoot. It was analyzed that the variables of the number of shoot per pruned branches, shoot diameter, shoot height and number of leaves per shoot were not significantly correlated to the score of VSD damage. Grouping of the resistance also performed similar results whereas mean of the sprouting variables were not different among group but the percentage of sprouted branches tend to be higher with the higher of the resistance (lower score. This result confirmed any mechanism of tolerance on VSD resistance by accelerating shoot rejuvenation on resistant plant. Key words : vascular-streak diaback, cocoa, resistance, characteristics of sprouting

Fitness of Bt-resistant cabbage loopers on Bt cotton plants.

Science.gov (United States)

Tetreau, Guillaume; Wang, Ran; Wang, Ping

2017-10-01

Development of resistance to the insecticidal toxins from Bacillus thuringiensis (Bt) in insects is the major threat to the continued success of transgenic Bt crops in agriculture. The fitness of Bt-resistant insects on Bt and non-Bt plants is a key parameter that determines the development of Bt resistance in insect populations. In this study, a comprehensive analysis of the fitness of Bt-resistant Trichoplusia ni strains on Bt cotton leaves was conducted. The Bt-resistant T. ni strains carried two genetically independent mechanisms of resistance to Bt toxins Cry1Ac and Cry2Ab. The effects of the two resistance mechanisms, individually and in combination, on the fitness of the T. ni strains on conventional non-Bt cotton and on transgenic Bt cotton leaves expressing a single-toxin Cry1Ac (Bollgard I) or two Bt toxins Cry1Ac and Cry2Ab (Bollgard II) were examined. The presence of Bt toxins in plants reduced the fitness of resistant insects, indicated by decreased net reproductive rate (R 0 ) and intrinsic rate of increase (r). The reduction in fitness in resistant T. ni on Bollgard II leaves was greater than that on Bollgard I leaves. A 12.4-day asynchrony of adult emergence between the susceptible T. ni grown on non-Bt cotton leaves and the dual-toxin-resistant T. ni on Bollgard II leaves was observed. Therefore, multitoxin Bt plants not only reduce the probability for T. ni to develop resistance but also strongly reduce the fitness of resistant insects feeding on the plants. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Improvement of the fungal biocontrol agent Trichoderma atroviride to enhance both antagonism and induction of plant systemic disease resistance.

Science.gov (United States)

Brunner, Kurt; Zeilinger, Susanne; Ciliento, Rosalia; Woo, Sheridian L; Lorito, Matteo; Kubicek, Christian P; Mach, Robert L

2005-07-01

Biocontrol agents generally do not perform well enough under field conditions to compete with chemical fungicides. We determined whether transgenic strain SJ3-4 of Trichoderma atroviride, which expresses the Aspergillus niger glucose oxidase-encoding gene, goxA, under a homologous chitinase (nag1) promoter had increased capabilities as a fungal biocontrol agent. The transgenic strain differed only slightly from the wild-type in sporulation or the growth rate. goxA expression occurred immediately after contact with the plant pathogen, and the glucose oxidase formed was secreted. SJ3-4 had significantly less N-acetylglucosaminidase and endochitinase activities than its nontransformed parent. Glucose oxidase-containing culture filtrates exhibited threefold-greater inhibition of germination of spores of Botrytis cinerea. The transgenic strain also more quickly overgrew and lysed the plant pathogens Rhizoctonia solani and Pythium ultimum. In planta, SJ3-4 had no detectable improved effect against low inoculum levels of these pathogens. Beans planted in heavily infested soil and treated with conidia of the transgenic Trichoderma strain germinated, but beans treated with wild-type spores did not germinate. SJ3-4 also was more effective in inducing systemic resistance in plants. Beans with SJ3-4 root protection were highly resistant to leaf lesions caused by the foliar pathogen B. cinerea. This work demonstrates that heterologous genes driven by pathogen-inducible promoters can increase the biocontrol and systemic resistance-inducing properties of fungal biocontrol agents, such as Trichoderma spp., and that these microbes can be used as vectors to provide plants with useful molecules (e.g., glucose oxidase) that can increase their resistance to pathogens.

Induced resistant mutations in alfalfa and broad bean against rust, leaf spot and wilh diseases by Gamma rays and ethylmethanesulfonate

International Nuclear Information System (INIS)

1988-01-01

In alfalfa after gamma irradiation with 50,100, and 150 krads, 38 rust resistant plants have been selected throughout a screening programme. During four months, cuttings were obtained from these plants individually. Results revealed that 20 plants were remar-kably surpassed the origin in the total fresh weight and in the average weight of each cutting. In broad bean, following gamma irradiation and EMS in two cuitivars for induction of wilt resistance. Seeds of these plants were sown in artificially infested soil . During the growing season, all susceptible plants were removed and at epidemic form of wilt disease

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.

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.

Induction of systemic resistance in plants by biochar, a soil-applied carbon sequestering agent.

Science.gov (United States)

Elad, Yigal; David, Dalia Rav; Harel, Yael Meller; Borenshtein, Menahem; Kalifa, Hananel Ben; Silber, Avner; Graber, Ellen R

2010-09-01

Biochar is the solid coproduct of biomass pyrolysis, a technique used for carbon-negative production of second-generation biofuels. The biochar can be applied as a soil amendment, where it permanently sequesters carbon from the atmosphere as well as improves soil tilth, nutrient retention, and crop productivity. In addition to its other benefits in soil, we found that soil-applied biochar induces systemic resistance to the foliar fungal pathogens Botrytis cinerea (gray mold) and Leveillula taurica (powdery mildew) on pepper and tomato and to the broad mite pest (Polyphagotarsonemus latus Banks) on pepper. Levels of 1 to 5% biochar in a soil and a coconut fiber-tuff potting medium were found to be significantly effective at suppressing both diseases in leaves of different ages. In long-term tests (105 days), pepper powdery mildew was significantly less severe in the biochar-treated plants than in the plants from the unamended controls although, during the final 25 days, the rate of disease development in the treatments and controls was similar. Possible biochar-related elicitors of systemic induced resistance are discussed.

Pest and disease resistance enhanced by heterologous suppression of a Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2.

Science.gov (United States)

Smigocki, Ann C; Wilson, Dennis

2004-12-01

The functional role of the Nicotiana plumbaginifolia cytochrome P450 gene CYP72A2 was investigated in transgenic plants. N. tabacum plants transformed with a sense or antisense CYP72A2 construct exhibited diminished heights, branched stems, smaller leaves and deformed flowers. Western blot analysis revealed reduced levels of a 58 kDa protein corresponding to CYP72A2, suggesting that the CYP72A2 homolog was suppressed in the sense and antisense plants. Transgenic plants had increased resistance to Manduca sexta larvae that consumed about 35 to 90 less of transgenic versus control leaves. A virulent strain of Pseudomonas syringae pv. tabaci induced a disease-limiting response followed by a delayed and decreased development of disease symptoms in the transgenics. CYP72A2 gene mediated resistance suggests that the plant-pest or -pathogen interactions may have been modified by changes in bioactive metabolite pools.

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...

Induced resistance by cresotic acid (3-hydroxy-4-methyl methylbenzoic acid) against wilt disease of melon and cotton

International Nuclear Information System (INIS)

Dong, H.; Li, Z.; Zhang, D.; Li, W.; Tang, W.

2004-01-01

Cresotic acid (3-hydroxy-4-methylbenzoic acid) was proved be active in controlling wilt diseases of melon and cotton plants grown in the house. Soil drench with 200-1000 ppm cresotic acid induced 62-77 %, 69-79 % and 50-60 % protection against Fusarium oxysporum f.sp melonis (FOM) in melon, Fusarium oxysporum f.sp vasinfectum (FOV) and Verticillium dahliae in cotton, respectively. Since no inhibitory effect of cresotic acid on mycelial growth of these three fungual pathogens was observed in vitro, it is suggested that control of these wilt diseases with cresotic acid resulted from induced resistance. Cresotic acid induced resistance in melon plants not only against race 0, race 1, race 2 and race 1,2, but also against a mixture of these four races of FOM, suggesting a non-race- specific resistance. Level of induced resistance by cresotic acid against FOM depended on inoculum pressure applied to melon plants. At 25 day after inoculation with FOM, percentage protection induced by cresotic acid under low inoculum pressure retained a level of 51 %, while under high inoculum pressure percentage protection decreased to only 10 %. High concentrations of cresotic acid significantly reduced plant growth. Reduction in fresh weight of melon (36-51%) and cotton (42-71%) was obtained with 500-1000 ppm cresotic acid, while only less than 8% reduction occurred with 100-200 ppm. (author)

Breeding wheat for disease resistance in Kenya

International Nuclear Information System (INIS)

Njau, P.N.; Kinyua, M.G.; Karanja, L.; Maling'a, J.

2001-01-01

Yellow rust caused by Puccinia striformis and stem rust caused by Puccinia graminis tritici are most destructive diseases in Kenya. In wheat improvement, development of varieties of wheat with resistance to these diseases has been among the foremost contributions in wheat breeding. In breeding programs each disease is considered as a separate problem. Attention has been given to varieties resistant to stem rust, yellow rust and leaf rust among other diseases. In the year 2001 program stem rust and yellow rust were recorded in all the sites where NPT was performed. Breeding for resistance for the two diseases is approached through the Introductions and Hybridisation. The Doubled Haploid Technique is used to quicken the time of homozygous lines production. The introduction and the homozygous lines are then evaluated for yield and disease resistance in the field under preliminary yield trials and the National Performance Trials (NPT) in 2001, 18 lines and 2 check varieties were included in the NPT. The results show that there were some differences in reaction to the three diseases where lines R946, K7972-1 and R899 had the lowest score of the diseases in all sites. In the commercial variety trial the results show that all the varietieshave become susceptible to stem rust and so the need to develop new cultivars which will be resistance to the rusts. Yombi a newly developed variety showed a substantially high level resistance. (author)

Molecular mapping of qBK1 WD , a major QTL for bakanae disease resistance in rice

OpenAIRE

Lee, Sais-Beul; Hur, Yeon-Jae; Cho, Jun-Hyeon; Lee, Jong-Hee; Kim, Tae-Heon; Cho, Soo-Min; Song, You-Chun; Seo, Young-Su; Lee, Jungkwan; Kim, Tae-sung; Park, Yong-Jin; Oh, Myung-Kyu; Park, Dong-Soo

2018-01-01

Background Bakanae or foot rot disease is a prominent disease of rice caused by Gibberella fujikuroi. This disease may infect rice plants from the pre-emergence stage to the mature stage. In recent years, raising rice seedlings in seed boxes for mechanical transplanting has increased the incidence of many seedling diseases; only a few rice varieties have been reported to exhibit resistance to bakanae disease. In this study, we attempted to identify quantitative trait loci (QTLs) conferring ba...

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.

Monoterpenes Support Systemic Acquired Resistance within and between Plants.

Science.gov (United States)

Riedlmeier, Marlies; Ghirardo, Andrea; Wenig, Marion; Knappe, Claudia; Koch, Kerstin; Georgii, Elisabeth; Dey, Sanjukta; Parker, Jane E; Schnitzler, Jörg-Peter; Vlot, A Corina

2017-06-01

This study investigates the role of volatile organic compounds in systemic acquired resistance (SAR), a salicylic acid (SA)-associated, broad-spectrum immune response in systemic, healthy tissues of locally infected plants. Gas chromatography coupled to mass spectrometry analyses of SAR-related emissions of wild-type and non-SAR-signal-producing mutant plants associated SAR with monoterpene emissions. Headspace exposure of Arabidopsis thaliana to a mixture of the bicyclic monoterpenes α-pinene and β-pinene induced defense, accumulation of reactive oxygen species, and expression of SA- and SAR-related genes, including the SAR regulatory AZELAIC ACID INDUCED1 ( AZI1 ) gene and three of its paralogs. Pinene-induced resistance was dependent on SA biosynthesis and signaling and on AZI1 Arabidopsis geranylgeranyl reductase1 mutants with reduced monoterpene biosynthesis were SAR-defective but mounted normal local resistance and methyl salicylate-induced defense responses, suggesting that monoterpenes act in parallel with SA The volatile emissions from SAR signal-emitting plants induced defense in neighboring plants, and this was associated with the presence of α-pinene, β-pinene, and camphene in the emissions of the "sender" plants. Our data suggest that monoterpenes, particularly pinenes, promote SAR, acting through ROS and AZI1 , and likely function as infochemicals in plant-to-plant signaling, thus allowing defense signal propagation between neighboring plants. © 2017 American Society of Plant Biologists. All rights reserved.

Evaluation of some garlic (Allium Sativum L.) mutants resistant to white rot disease by RAPD analysis

International Nuclear Information System (INIS)

Nabulsi, I.; Al-Safadi, B.; Mir ali, N.; Arabi, M.I.E.

2002-01-01

Random amplified polymorphic DNA (RAPD) analysis was used to evaluate genetic diversity among eight garlic mutants resistant to white rot disease (Sclerotium cepivorum) and two controls. Twelve of 13 synthetic random primers were found to identify polymorphism in amplification products. Mutants characterised with moderate resistance to white rot were closely related to the control using cluster and correlation analyses. On the other hand, highly resistant mutants were quite distant from the control with low correlation coefficients. The banding patterns produced by primer OPB-15 (GGAAGGGTGTT) with highly resistant mutants may be used as genetic markers for early selection of resistant plants. (author)

Agronomic characters and lodging resistance of plant height mutants of rice

International Nuclear Information System (INIS)

Zhang Zhonggui; Wu Yuejin; Liu Binmei; Xu Xue; Zhang Lili; Wang Min

2010-01-01

Fourteen plant height mutants of Nipponbare were used to study the effect of plant height on the agronomic characters and lodging resistance. The results indicated that the plant height was positively correlated with spike length, third internode length, height of gravity center, fresh weight of main stem, dry weight of main stem, thousand-grain weight, grain-yield per plant and biological yield, and the second internode length. Meanwhile, plant height played an important role in lodging resistance, it was significantly positively correlated with lodging index and negatively correlated with bending moment and culm type index. The correlation between agronomic characters and lodging resistance showed that several agronomic characters had strong impact on the lodging resistance, such as spike length, height of gravity center, basal internode length ( first and second internode), fresh and dry weight of main stem, dry weight of basal internode, seed setting, thousand-grain weight, grain-weight per plant and biological yield. (authors)

Adult Plant Leaf Rust Resistance Derived from Toropi Wheat is Conditioned by Lr78 and Three Minor QTL.

Science.gov (United States)

Kolmer, J A; Bernardo, A; Bai, G; Hayden, M J; Chao, S

2018-02-01

Leaf rust caused by Puccinia triticina is an important disease of wheat in many regions worldwide. Durable or long-lasting leaf rust resistance has been difficult to achieve because populations of P. triticina are highly variable for virulence to race-specific resistance genes, and respond to selection by resistance genes in released wheat cultivars. The wheat cultivar Toropi, developed and grown in Brazil, was noted to have long-lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat background. In the first population, a single gene with major effects on chromosome 5DS that mapped 2.2 centimorgans distal to IWA6289, strongly reduced leaf rust severity in all 3 years of field plot tests. This gene for adult plant leaf rust resistance was designated as Lr78. In the second population, quantitative trait loci (QTL) with small effects on chromosomes 1BL, 3BS, and 4BS were found. These QTL expressed inconsistently over 4 years of field plot tests. The adult plant leaf rust resistance derived from Toropi involved a complex combination of QTL with large and small effects.

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.

Identification of Ganoderma Disease Resistance Loci Using Natural Field Infection of an Oil Palm Multiparental Population

Directory of Open Access Journals (Sweden)

Sébastien Tisné

2017-06-01

Full Text Available Multi-parental populations are promising tools for identifying quantitative disease resistance loci. Stem rot caused by Ganoderma boninense is a major threat to palm oil production, with yield losses of up to 80% prompting premature replantation of palms. There is evidence of genetic resistance sources, but the genetic architecture of Ganoderma resistance has not yet been investigated. This study aimed to identify Ganoderma resistance loci using an oil palm multi-parental population derived from nine major founders of ongoing breeding programs. A total of 1200 palm trees of the multi-parental population was planted in plots naturally infected by Ganoderma, and their health status was assessed biannually over 25 yr. The data were treated as survival data, and modeled using the Cox regression model, including a spatial effect to take the spatial component in the spread of Ganoderma into account. Based on the genotypes of 757 palm trees out of the 1200 planted, and on pedigree information, resistance loci were identified using a random effect with identity-by-descent kinship matrices as covariance matrices in the Cox model. Four Ganoderma resistance loci were identified, two controlling the occurrence of the first Ganoderma symptoms, and two the death of palm trees, while favorable haplotypes were identified among a major gene pool for ongoing breeding programs. This study implemented an efficient and flexible QTL mapping approach, and generated unique valuable information for the selection of oil palm varieties resistant to Ganoderma disease.

Identification of Ganoderma Disease Resistance Loci Using Natural Field Infection of an Oil Palm Multiparental Population

Science.gov (United States)

Tisné, Sébastien; Pomiès, Virginie; Riou, Virginie; Syahputra, Indra; Cochard, Benoît; Denis, Marie

2017-01-01

Multi-parental populations are promising tools for identifying quantitative disease resistance loci. Stem rot caused by Ganoderma boninense is a major threat to palm oil production, with yield losses of up to 80% prompting premature replantation of palms. There is evidence of genetic resistance sources, but the genetic architecture of Ganoderma resistance has not yet been investigated. This study aimed to identify Ganoderma resistance loci using an oil palm multi-parental population derived from nine major founders of ongoing breeding programs. A total of 1200 palm trees of the multi-parental population was planted in plots naturally infected by Ganoderma, and their health status was assessed biannually over 25 yr. The data were treated as survival data, and modeled using the Cox regression model, including a spatial effect to take the spatial component in the spread of Ganoderma into account. Based on the genotypes of 757 palm trees out of the 1200 planted, and on pedigree information, resistance loci were identified using a random effect with identity-by-descent kinship matrices as covariance matrices in the Cox model. Four Ganoderma resistance loci were identified, two controlling the occurrence of the first Ganoderma symptoms, and two the death of palm trees, while favorable haplotypes were identified among a major gene pool for ongoing breeding programs. This study implemented an efficient and flexible QTL mapping approach, and generated unique valuable information for the selection of oil palm varieties resistant to Ganoderma disease. PMID:28592650

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.

Resistance Against Basil Downy Mildew in Ocimum Species.

Science.gov (United States)

Ben-Naim, Yariv; Falach, Lidan; Cohen, Yigal

2015-06-01

Downy mildew, caused by the oomycete Peronospora belbahrii, is a devastating disease of sweet basil. In this study, 113 accessions of Ocimum species (83 Plant Introduction entries and 30 commercial entries) were tested for resistance against downy mildew at the seedling stage in growth chambers, and during three seasons, in the field. Most entries belonging to O. basilicum were highly susceptible whereas most entries belonging to O. americanum, O. kilimanadascharicum, O. gratissimum, O. campechianum, or O. tenuiflorum were highly resistant at both the seedling stage and the field. Twenty-seven highly resistant individual plants were each crossed with the susceptible sweet basil 'Peri', and the F1 progeny plants were examined for disease resistance. The F1 plants of two crosses were highly resistant, F1 plants of 24 crosses were moderately resistant, and F1 plants of one cross were susceptible, suggesting full, partial, or no dominance of the resistance gene(s), respectively. These data confirm the feasibility of producing downy mildew-resistant cultivars of sweet basil by crossing with wild Ocimum species.

The Impact of "Coat Protein-Mediated Virus Resistance" in Applied Plant Pathology and Basic Research.

Science.gov (United States)

Lindbo, John A; Falk, Bryce W

2017-06-01

Worldwide, plant viruses cause serious reductions in marketable crop yield and in some cases even plant death. In most cases, the most effective way to control virus diseases is through genetically controlled resistance. However, developing virus-resistant (VR) crops through traditional breeding can take many years, and in some cases is not even possible. Because of this, the demonstration of the first VR transgenic plants in 1985 generated much attention. This seminal report served as an inflection point for research in both basic and applied plant pathology, the results of which have dramatically changed both basic research and in a few cases, commercial crop production. The typical review article on this topic has focused on only basic or only applied research results stemming from this seminal discovery. This can make it difficult for the reader to appreciate the full impact of research on transgenic virus resistance, and the contributions from fundamental research that led to translational applications of this technology. In this review, we take a global view of this topic highlighting the significant changes to both basic and applied plant pathology research and commercial food production that have accumulated in the last 30 plus years. We present these milestones in the historical context of some of the scientific, economic, and environmental drivers for developing specific VR crops. The intent of this review is to provide a single document that adequately records the significant accomplishments of researchers in both basic and applied plant pathology research on this topic and how they relate to each other. We hope this review therefore serves as both an instructional tool for students new to the topic, as well as a source of conversation and discussion for how the technology of engineered virus resistance could be applied in the future.

Engineering Plants for Geminivirus Resistance with CRISPR/Cas9 System

KAUST Repository

Zaidi, Syed Shan-e-Ali; Mansoor, Shahid; Ali, Zahir; Tashkandi, Manal; Mahfouz, Magdy M.

2016-01-01

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.

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.

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.

The uptake, distribution and translocation of 86Rb in alfalfa plants susceptible and resistant to the bacterial wilt and the effect of Corynebacterium insidiosum upon these processes

International Nuclear Information System (INIS)

Hanker, I.; Kudelova, A.

1981-01-01

Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86 Rb + , at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86 Rb + uptake per plant in the course of a 14-day-period following inoculation; however, it affected its distribution differently in the S- and the R-plants. 86 Rb + uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86 Rb + ), with the ions more slowly translocated to the shoots in diseased S-plants than in diseased R-plants. Likely factors causing these effects and their relationship to alfalfa resistance to bacterial wilt are discussed. (author)

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

Identification of Ganoderma Disease Resistance Loci Using Natural Field Infection of an Oil Palm Multiparental Population.

Science.gov (United States)

Tisné, Sébastien; Pomiès, Virginie; Riou, Virginie; Syahputra, Indra; Cochard, Benoît; Denis, Marie

2017-06-07

Multi-parental populations are promising tools for identifying quantitative disease resistance loci. Stem rot caused by Ganoderma boninense is a major threat to palm oil production, with yield losses of up to 80% prompting premature replantation of palms. There is evidence of genetic resistance sources, but the genetic architecture of Ganoderma resistance has not yet been investigated. This study aimed to identify Ganoderma resistance loci using an oil palm multi-parental population derived from nine major founders of ongoing breeding programs. A total of 1200 palm trees of the multi-parental population was planted in plots naturally infected by Ganoderma , and their health status was assessed biannually over 25 yr. The data were treated as survival data, and modeled using the Cox regression model, including a spatial effect to take the spatial component in the spread of Ganoderma into account. Based on the genotypes of 757 palm trees out of the 1200 planted, and on pedigree information, resistance loci were identified using a random effect with identity-by-descent kinship matrices as covariance matrices in the Cox model. Four Ganoderma resistance loci were identified, two controlling the occurrence of the first Ganoderma symptoms, and two the death of palm trees, while favorable haplotypes were identified among a major gene pool for ongoing breeding programs. This study implemented an efficient and flexible QTL mapping approach, and generated unique valuable information for the selection of oil palm varieties resistant to Ganoderma disease. Copyright © 2017 Tisné et al.

Mapping of quantitative adult plant field resistance to leaf rust and stripe rust in two European winter wheat populations reveals co-location of three QTL conferring resistance to both rust pathogens.

Science.gov (United States)

Buerstmayr, Maria; Matiasch, Lydia; Mascher, Fabio; Vida, Gyula; Ittu, Marianna; Robert, Olivier; Holdgate, Sarah; Flath, Kerstin; Neumayer, Anton; Buerstmayr, Hermann

2014-09-01

We detected several, most likely novel QTL for adult plant resistance to rusts. Notably three QTL improved resistance to leaf rust and stripe rust simultaneously indicating broad spectrum resistance QTL. The rusts of wheat (Puccinia spp.) are destructive fungal wheat diseases. The deployment of resistant cultivars plays a central role in integrated rust disease management. Durability of resistance would be preferred, but is difficult to analyse. The Austrian winter wheat cultivar Capo was released in the 1989 and grown on a large acreage during more than two decades and maintained a good level of quantitative leaf rust and stripe rust resistance. Two bi-parental mapping populations: Capo × Arina and Capo × Furore were tested in multiple environments for severity of leaf rust and stripe rust at the adult plant stage in replicated field experiments. Quantitative trait loci associated with leaf rust and stripe rust severity were mapped using DArT and SSR markers. Five QTL were detected in multiple environments associated with resistance to leaf rust designated as QLr.ifa-2AL, QLr.ifa-2BL, QLr.ifa-2BS, QLr.ifa-3BS, and QLr.ifa-5BL, and five for resistance to stripe rust QYr.ifa-2AL, QYr.ifa-2BL, QYr.ifa-3AS, QYr.ifa-3BS, and QYr.ifa-5A. For all QTL apart from two (QYr.ifa-3AS, QLr.ifa-5BL) Capo contributed the resistance improving allele. The leaf rust and stripe rust resistance QTL on 2AL, 2BL and 3BS mapped to the same chromosome positions, indicating either closely linked genes or pleiotropic gene action. These three multiple disease resistance QTL (QLr.ifa-2AL/QYr.ifa-2AL, QLr.ifa.2BL/QYr.ifa-2BL, QLr.ifa-3BS/QYr.ifa.3BS) potentially contribute novel resistance sources for stripe rust and leaf rust. The long-lasting resistance of Capo apparently rests upon a combination of several genes. The described germplasm, QTL and markers are applicable for simultaneous resistance improvement against leaf rust and stripe rust.

Stress proteins and phytohormones: their role in formation of plant resistance

International Nuclear Information System (INIS)

Kosakivska, I.V.

2005-01-01

Full text: Using the disc-electrophoresis methods, we have studied protein biosynthesis of different plants, including 11 species of Orchidaceae, some other tropical and subtropical plants, 9 different fruit plants, and 4 cultivars of Triticum aestivum L. under stresses factors such as high and low temperature, clinostating, radioactive irradiation and osmotic shock. Specific and unspecific reactions of plants protein system on stresses were found. De novo synthesis of 35 and 45 kD polypeptides were observed in total and mitochondrial proteins fractions after heat-shock and radioactive irradiation. This suggests that mitochondries participate in formation of plant resistance. Intensive synthesis of ABA revealed as the universal reaction of all studied plants on action of different kinds of stresses. Specific changes in balance of phytohormones were found under different stresses. We observed the correlation between endogenous ABA, IAA and cytokinin level and plant resistance. We also found the interaction between the process of biosynthesis of proteins and phytohormone balance, as well as their direct participation in formation of plant resistance. (author)

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

Radiation therapy for resistant sternal hydatid disease

International Nuclear Information System (INIS)

Ulger, S.; Barut, H.; Tunc, M.; Aydinkarahaliloglu, E.; Aydin, E.; Karaoglanoglu, N.; Gokcek, A.

2013-01-01

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.)

Application of Copper-Chitosan Nanoparticles Stimulate Growth and Induce Resistance in Finger Millet (Eleusine coracana Gaertn.) Plants against Blast Disease.

Science.gov (United States)

Sathiyabama, Muthukrishnan; Manikandan, Appu

2018-02-28

Copper-chitosan nanoparticle (CuChNp) was synthesized and used to study its effect on finger millet plant as a model plant system. Our objective was to explore the efficacy of CuChNp application to control blast disease of finger millet. CuChNp was applied to finger millet either as a foliar spray or as a combined application (involving seed coat and foliar spray). Both the application methods enhanced growth profile of finger millet plants and increased yield. The increased yield was nearly 89% in combined application method. Treated finger millet plants challenged with Pyricularia grisea showed suppression of blast disease development when compared to control. Nearly 75% protection was observed in the combined application of CuChNp to finger millet plants. In CuChNp treated finger millet plants, a significant increase in defense enzymes was observed, which was detected both qualitatively and quantitatively. The suppression of blast disease correlates well with increased defense enzymes in CuChNp treated finger millet plants.

XA23 is an executor R protein and confers broad-spectrum disease resistance in rice.

Science.gov (United States)

Wang, Chunlian; Zhang, Xiaoping; Fan, Yinglun; Gao, Ying; Zhu, Qinlong; Zheng, Chongke; Qin, Tengfei; Li, Yanqiang; Che, Jinying; Zhang, Mingwei; Yang, Bing; Liu, Yaoguang; Zhao, Kaijun

2014-11-09

The majority of plant disease resistance (R) genes encode proteins that share common structural features. However, the transcription activator-like effector (TALE) associated executor type R genes show no considerable sequence homology to any known R genes. We adopted a map-based cloning approach and TALE-based technology to isolate and characterize Xa23, a new executor R gene derived from the wild rice (Oryza rufipogon) that confers an extremely broad spectrum of resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). Xa23 encodes a 113-amino acid protein that shares 50% identity to the known executor R protein XA10. The predicted transmembrane helices in XA23 also overlap with those of XA10. Unlike Xa10, however, Xa23 transcription is specifically activated by AvrXa23, a TALE present in all examined Xoo field isolates. Moreover, the susceptible xa23 allele has an identical open reading frame of Xa23, but differs in promoter region by lacking the TALE binding-element (EBE) for AvrXa23. XA23 can trigger strong hypersensitive response in rice, tobacco and tomato. Our results provide the first evidence that plant genomes have an executor R gene family in which members execute their function and spectrum of disease resistance by recognizing the cognate TALEs in pathogen. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

Cadmium resistance in tobacco plants expressing the MuSI gene

OpenAIRE

Kim, Young-Nam; Kim, Ji-Seoung; Seo, Sang-Gyu; Lee, Youngwoo; Baek, Seung-Woo; Kim, Il-Sup; Yoon, Ho-Sung; Kim, Kwon-Rae; Kim, Sun-Hyung; Kim, Kye-Hoon

2011-01-01

MuSI, a gene that corresponds to a domain that contains the rubber elongation factor (REF), is highly homologous to many stress-related proteins in plants. Since MuSI is up-regulated in the roots of plants treated with cadmium or copper, the involvement of MuSI in cadmium tolerance was investigated in this study. Escherichia coli cells overexpressing MuSI were more resistant to Cd than wild-type cells transfected with vector alone. MuSI transgenic plants were also more resistant to Cd. MuSI t...

Increased resistance to a generalist herbivore in a salinity-stressed non-halophytic plant.

Science.gov (United States)

Renault, Sylvie; Wolfe, Scott; Markham, John; Avila-Sakar, Germán

2016-01-01

Plants often grow under the combined stress of several factors. Salinity and herbivory, separately, can severely hinder plant growth and reproduction, but the combined effects of both factors are still not clearly understood. Salinity is known to reduce plant tissue nitrogen content and growth rates. Since herbivores prefer tissues with high N content, and biochemical pathways leading to resistance are commonly elicited by salt-stress, we hypothesized that plants growing in saline conditions would have enhanced resistance against herbivores. The non-halophyte, Brassica juncea, and the generalist herbivore Trichoplusia ni were used to test the prediction that plants subjected to salinity stress would be both more resistant and more tolerant to herbivory than those growing without salt stress. Plants were grown under different NaCl levels, and either exposed to herbivores and followed by removal of half of their leaves, or left intact. Plants were left to grow and reproduce until senescence. Tissue quality was assessed, seeds were counted and biomass of different organs measured. Plants exposed to salinity grew less, had reduced tissue nitrogen, protein and chlorophyll content, although proline levels increased. Specific leaf area, leaf water content, transpiration and root:shoot ratio remained unaffected. Plants growing under saline condition had greater constitutive resistance than unstressed plants. However, induced resistance and tolerance were not affected by salinity. These results support the hypothesis that plants growing under salt-stress are better defended against herbivores, although in B. juncea this may be mostly through resistance, and less through tolerance. Published by Oxford University Press on behalf of the Annals of Botany Company.

Engineering cotton (Gossypium hirsutum L.) for resistance to cotton leaf curl disease using viral truncated AC1 DNA sequences.

Science.gov (United States)

Hashmi, Jamil A; Zafar, Yusuf; Arshad, Muhammad; Mansoor, Shahid; Asad, Shaheen

2011-04-01

Several important biological processes are performed by distinct functional domains found on replication-associated protein (Rep) encoded by AC1 of geminiviruses. Two truncated forms of replicase (tAC1) gene, capable of expressing only the N-terminal 669 bp (5'AC1) and C-terminal 783 bp (3'AC1) nucleotides cloned under transcriptional control of the CaMV35S were introduced into cotton (Gossypium hirsutum L.) using LBA4404 strain of Agrobacterium tumefaciens to make use of an interference strategy for impairing cotton leaf curl virus (CLCuV) infection in transgenic cotton. Compared with nontransformed control, we observed that transgenic cotton plants overexpressing either N-terminal (5'AC1) or C-terminal (3'AC1) sequences confer resistance to CLCuV by inhibiting replication of viral genomic and β satellite DNA components. Molecular analysis by Northern blot hybridization revealed high transgene expression in early and late growth stages associated with inhibition of CLCuV replication. Of the eight T(1) transgenic lines tested, six had delayed and minor symptoms as compared to nontransformed control lines which developed disease symptoms after 2-3 weeks of whitefly-mediated viral delivery. Virus biological assay and growth of T(2) plants proved that transgenic cotton plants overexpressing 5'- and 3'AC1 displayed high resistance level up to 72, 81%, respectively, as compared to non-transformed control plants following inoculation with viruliferous whiteflies giving significantly high cotton seed yield. Progeny analysis of these plants by polymerase chain reaction (PCR), Southern blotting and virus biological assay showed stable transgene, integration, inheritance and cotton leaf curl disease (CLCuD) resistance in two of the eight transgenic lines having single or two transgene insertions. Transgenic cotton expressing partial AC1 gene of CLCuV can be used as virus resistance source in cotton breeding programs aiming to improve virus resistance in cotton crop.

Induced resistance in tomato by SAR activators during predisposing salinity stress

Directory of Open Access Journals (Sweden)

Matthew Francis Pye

2013-05-01

Full Text Available Plant activators are chemicals that induce disease resistance. The phytohormone salicylic acid (SA is a crucial signal for systemic acquired resistance (SAR, and SA-mediated resistance is a target of several commercial plant activators, including Actigard (1,2,3-benzothiadiazole-7-thiocarboxylic acid-s-methyl-ester, BTH and Tiadinil (N-(3-chloro-4-methylphenyl-4-methyl-1,2,3-thiadiazole-5-carboxamide, TDL. BTH and TDL were examined for their impact on abscisic acid (ABA-mediated, salt-induced disease predisposition in tomato seedlings. A brief episode of salt stress to roots significantly increased the severity of disease caused by Pseudomonas syringae pv. tomato (Pst and Phytophthora capsici relative to non-stressed plants. Root treatment with TDL induced resistance to Pst in leaves and provided protection in both non-stressed and salt-stressed seedlings in WT and highly susceptible NahG plants. Non-stressed and salt-stressed ABA-deficient sitiens mutants were highly resistant to Pst. Neither TDL nor BTH induced resistance to root infection by P. capsici, nor did they moderate the salt-induced increment in disease severity. Root treatment with these plant activators increased the levels of ABA in roots and shoots similar to levels observed in salt-stressed plants. The results indicate that SAR activators can protect tomato plants from bacterial speck disease under predisposing salt stress, and suggest that some SA-mediated defense responses function sufficiently in plants with elevated levels of ABA.

The role of aluminum sensing and signaling in plant aluminum resistance.

Science.gov (United States)

Liu, Jiping; Piñeros, Miguel A; Kochian, Leon V

2014-03-01

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 resistance, 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 transcriptional activation of resistance genes has led to the identification of several transcription factors as well as cis-elements in the promoters of Al resistance genes that play a role in greater Al-induced gene expression as well as higher constitutive expression of resistance genes in some plant species. Finally, 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. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Identifying and utilizing resistance to Puccinia striiformis in wheat

International Nuclear Information System (INIS)

Line, R.F.; Allan, R.E.; Konzak, C.F.

1976-01-01

Resistance to Puccinia striiformis in wheat cultivars, breeding lines, and induced mutants, was studied on plants exposed to natural rust inoculum at field sites and on plants inoculated with specific races and grown under controlled temperatures. Based on infection types and disease intensity at various stages of plant growth throughout the duration of rust establishment, the following resistance-types (R-types) were identified: R-type 1, plants resistant or susceptible at all stages of growth and at both low and high temperatures throughout duration of rust establishment; R-type 2, plants initially resistant in the seedling stage but eventually become susceptible, plants resistant at later stages in the field; R-type 3, variable resistance in the seedling stage, high resistance in later growth stages; R-type 4, plants resistant in the eedling stage, but susceptible in late stages of growth; R-type 5, plants susceptible, but the pathogen is slow to sporulate and consequently, rust increases slower in the field; R-type 6, plants susceptible at low temperatures and resistant at high temperatures at all stages of growth; R-type 7, plants very susceptible at both low and high temperatures in the seedling stage and at low temperatures in later stages; when temperatures are high, plants become more resistant in later stages; R-type 8, plants susceptible at all stages, when rust intensity is low and when not under stress, but become more resistant when intensity is high or under moderate stress in the field. Combinations of the above types were also observed. Techniques for identifying resistance to stripe rust, race specificity of the resistance-types, relationship of plant growth habit and head characteristics to disease intensity, historical significance of various types of resistance in the United States, and methods of using the resistance-types are also discussed. (author)

The pepper Bs4C proteins are localized to the endoplasmic reticulum (ER) membrane and confer disease resistance to bacterial blight in transgenic rice.

Science.gov (United States)

Wang, Jun; Zeng, Xuan; Tian, Dongsheng; Yang, Xiaobei; Wang, Lanlan; Yin, Zhongchao

2018-03-30

Transcription activator-like effector (TALE)-dependent dominant disease resistance (R) genes in plants, also referred to as executor R genes, are induced on infection by phytopathogenic bacteria of the genus Xanthomonas harbouring the corresponding TALE genes. Unlike the traditional R proteins, the executor R proteins do not determine the resistance specificity and may function broadly in different plant species. The executor R gene Bs4C-R in the resistant genotype PI 235047 of the pepper species Capsicum pubescens (CpBs4C-R) confers disease resistance to Xanthomonas campestris pv. vesicatoria (Xcv) harbouring the TALE genes avrBsP/avrBs4. In this study, the synthetic genes of CpBs4C-R and two other Bs4C-like genes, the susceptible allele in the genotype PI585270 of C. pubescens (CpBs4C-S) and the CaBs4C-R homologue gene in the cultivar 'CM334' of Capsicum annum (CaBs4C), were characterized in tobacco (Nicotiana benthamiana) and rice (Oryza sativa). The Bs4C genes induced cell death in N. benthamiana. The functional Bs4C-eCFP fusion proteins were localized to the endoplasmic reticulum (ER) membrane in the leaf epidermal cells of N. benthamiana. The Xa10 promoter-Bs4C fusion genes in transgenic rice conferred strain-specific disease resistance to Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight in rice, and were specifically induced by the Xa10-incompatible Xoo strain PXO99 A (pHM1avrXa10). The results indicate that the Bs4C proteins from pepper species function broadly in rice and the Bs4C protein-mediated cell death from the ER is conserved between dicotyledonous and monocotyledonous plants, which can be utilized to engineer novel and enhanced disease resistance in heterologous plants. © 2018 TEMASEK LIFE SCIENCES LABORATORY. MOLECULAR PLANT PATHOLOGY © 2018 JOHN WILEY & SONS LTD.

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.

Quantitative Resistance to Plant Pathogens in Pyramiding Strategies for Durable Crop Protection

Directory of Open Access Journals (Sweden)

Marie-Laure Pilet-Nayel

2017-10-01

Full Text Available Quantitative resistance has gained interest in plant breeding for pathogen control in low-input cropping systems. Although quantitative resistance frequently has only a partial effect and is difficult to select, it is considered more durable than major resistance (R genes. With the exponential development of molecular markers over the past 20 years, resistance QTL have been more accurately detected and better integrated into breeding strategies for resistant varieties with increased potential for durability. This review summarizes current knowledge on the genetic inheritance, molecular basis, and durability of quantitative resistance. Based on this knowledge, we discuss how strategies that combine major R genes and QTL in crops can maintain the effectiveness of plant resistance to pathogens. Combining resistance QTL with complementary modes of action appears to be an interesting strategy for breeding effective and potentially durable resistance. Combining quantitative resistance with major R genes has proven to be a valuable approach for extending the effectiveness of major genes. In the plant genomics era, improved tools and methods are becoming available to better integrate quantitative resistance into breeding strategies. Nevertheless, optimal combinations of resistance loci will still have to be identified to preserve resistance effectiveness over time for durable crop protection.

Epidemiology: Past, Present, and Future Impacts on Understanding Disease Dynamics and Improving Plant Disease Management-A Summary of Focus Issue Articles.

Science.gov (United States)

Ojiambo, P S; Yuen, J; van den Bosch, F; Madden, L V

2017-10-01

Epidemiology has made significant contributions to plant pathology by elucidating the general principles underlying the development of disease epidemics. This has resulted in a greatly improved theoretical and empirical understanding of the dynamics of disease epidemics in time and space, predictions of disease outbreaks or the need for disease control in real-time basis, and tactical and strategic solutions to disease problems. Availability of high-resolution experimental data at multiple temporal and spatial scales has now provided a platform to test and validate theories on the spread of diseases at a wide range of spatial scales ranging from the local to the landscape level. Relatively new approaches in plant disease epidemiology, ranging from network to information theory, coupled with the availability of large-scale datasets and the rapid development of computer technology, are leading to revolutionary thinking about epidemics that can result in considerable improvement of strategic and tactical decision making in the control and management of plant diseases. Methods that were previously restricted to topics such as population biology or evolution are now being employed in epidemiology to enable a better understanding of the forces that drive the development of plant disease epidemics in space and time. This Focus Issue of Phytopathology features research articles that address broad themes in epidemiology including social and political consequences of disease epidemics, decision theory and support, pathogen dispersal and disease spread, disease assessment and pathogen biology and disease resistance. It is important to emphasize that these articles are just a sample of the types of research projects that are relevant to epidemiology. Below, we provide a succinct summary of the articles that are published in this Focus Issue .

Release of Antibiotic Resistant Bacteria by a Waste Treatment Plant from Romania.

Science.gov (United States)

Lupan, Iulia; Carpa, Rahela; Oltean, Andreea; Kelemen, Beatrice Simona; Popescu, Octavian

2017-09-27

The occurrence and spread of bacterial antibiotic resistance are subjects of great interest, and the role of wastewater treatment plants has been attracting particular interest. These stations are a reservoir of bacteria, have a large range of organic and inorganic substances, and the amount of bacteria released into the environment is very high. The main purpose of the present study was to assess the removal degree of bacteria with resistance to antibiotics and identify the contribution of a wastewater treatment plant to the microbiota of Someşul Mic river water in Cluj county. The resistance to sulfamethoxazole and tetracycline and some of their representative resistance genes: sul1, tet(O), and tet(W) were assessed in this study. The results obtained showed that bacteria resistant to sulphonamides were more abundant than those resistant to tetracycline. The concentration of bacteria with antibiotic resistance changed after the treatment, namely, bacteria resistant to sulfamethoxazole. The removal of all bacteria and antibiotic-resistant bacteria was 98-99% and the degree of removal of bacteria resistant to tetracycline was higher than the bacteria resistant to sulfamethoxazole compared to total bacteria. The wastewater treatment plant not only contributed to elevating ARG concentrations, it also enhanced the possibility of horizontal gene transfer (HGT) by increasing the abundance of the intI1 gene. Even though the treatment process reduced the concentration of bacteria by two orders of magnitude, the wastewater treatment plant in Cluj-Napoca contributed to an increase in antibiotic-resistant bacteria concentrations up to 10 km downstream of its discharge in Someşul Mic river.

Utilization of Mutagenic Treatments for Improving Barley Disease Resistance to Powdery Mildew

International Nuclear Information System (INIS)

Amer, M.; Fahim, M.M.; Moustafa, N.A.

2008-01-01

This program aims to improve barley (Hordeum vulgar L.) resistance to powdery mildew (Erysiphe graminis f. sp. hordi) using mutation induction technique via physical and chemical mutagens. Grains of two local cultivars were treated with gamma rays (150, 250 GY) at a dose rate of 9.02 Rad/ Sec alone or with the concentrations of chemical mutagens, i.e.,EMS (4 and 8 mM), MH (10 and 20 mM) for two hours. After mass selection for the resistance in M2, the two cultivars were varied in their responses to the fifteen treatments. In M3 generation, the frequencies of plant resistance were increased at 20 mM of MH, 8 mM of EMS or 250 GY with either of them for the cultivar G124. However, the same trend was also found at 10 mM of MH, 250GY alone and with 4 or 8 mM EMS for cultivar G125. Moreover, eight mutants were selected from the progenies of M4 plants and evaluated in M5 generation. These mutants are characterized by highly disease resistance and high yield components, one of them has been characterized by non crytics and awnless .The desirable mutants should go to further evaluation for grain yield and grain quality in subsequent generations. (author)

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.

Genetic diversity/impurity estimation in sources of natural resistance against cotton leaf curl disease in pakistan

International Nuclear Information System (INIS)

Sarwar, G.

2007-01-01

Cotton accounts for more than 60% of Pakistan's export earnings through the export of both raw cotton and cotton products. An epidemic of cotton leaf curl disease (CLCuD) in Pakistan during the 1990s led to the withdrawal of high yielding cotton cultivars. Due of their susceptibility to the disease. The identification of natural resistance in some genotypes provided a means to manage reduce losses due to the disease. But it has been an adversity that almost all these resistant varieties have ultimately 'lost' their resistance. There are also reports that the original sources of resistance, as well as the varieties developed from them, are now susceptible to the disease when grafted with infected scion. For the present studies. Seed of two resistant varieties (LRA-5166 and (CP-152) was obtained from six different research organizations. Plants raised from these seed were grafted with symptomatic scion and used for morphological comparisons. Our results indicated that the genetic pool of these cultivars is not well maintained and that an unacceptable diversity impurity is present within and among the genetic stock of both these lines. There is thus a requirement for screening of these elite lines at the molecular level to ensure the purity of these varieties for future development. The virus causing CLCuD showed change by recombination making the search for new sources of resistance, as well as the maintenance of established sources, indispensable for the sustainable cotton production in Pakistan. (author)

A Rice Gene Homologous to Arabidopsis AGD2-LIKE DEFENSE1 Participates in Disease Resistance Response against Infection with Magnaporthe oryzae

Directory of Open Access Journals (Sweden)

Ga Young Jung

2016-08-01

Full Text Available ALD1 (ABERRANT GROWTH AND DEATH2 [AGD2]-LIKE DEFENSE1 is one of the key defense regulators in Arabidopsis thaliana and Nicotiana benthamiana. In these model plants, ALD1 is responsible for triggering basal defense response and systemic resistance against bacterial infection. As well ALD1 is involved in the production of pipecolic acid and an unidentified compound(s for systemic resistance and priming syndrome, respectively. These previous studies proposed that ALD1 is a potential candidate for developing genetically modified (GM plants that may be resistant to pathogen infection. Here we introduce a role of ALD1-LIKE gene of Oryza sativa, named as OsALD1, during plant immunity. OsALD1 mRNA was strongly transcribed in the infected leaves of rice plants by Magnaporthe oryzae, the rice blast fungus. OsALD1 proteins predominantly localized at the chloroplast in the plant cells. GM rice plants over-expressing OsALD1 were resistant to the fungal infection. The stable expression of OsALD1 also triggered strong mRNA expression of PATHOGENESIS-RELATED PROTEIN1 genes in the leaves of rice plants during infection. Taken together, we conclude that OsALD1 plays a role in disease resistance response of rice against the infection with rice blast fungus.

Induction of resistance to rice tungro virus disease in rice cultivar Pusa 2-21 through irradiation

International Nuclear Information System (INIS)

Mathur, S.C.; Rao, M.; Prakash, Jitendra

1979-01-01

The dry seeds of Pusa 2-21, a moderately resistant rice cultivar, were subjected to 10, 15 and 20 Krad (dose rate 12.3 Krad/min) radiation dosages of gamma rays to induce resistance against rice tungro virus disease. The height of M 1 seedling was significantly reduced in 15 and 20 Krad treatments. However, there was no effect of gamma irradiation on seed germination. A limited population of M 2 and M 3 generation was screened at the rate of 3 viruliferous leafhoppers/seedling using single plant caging technique. In M 2 generation 22.0, 17.6 and 25.0 percent seedlings exhibited green colour (symptomless) representing resistant reaction to the disease in 10, 15 and 20 Krad treatments, respectively. Out of 1470 seedlings in M 3 generation, 2.7 percent seedlings showing no symptoms of tungro could be isolated indicating the possibility of inducing higher degree of resistance than that of the parent to RTV through irradiation for the first time. (auth.)

The Epl1 and Sm1 proteins from Trichoderma atroviride and Trichoderma virens differentially modulate systemic disease resistance against different life style pathogens in Solanum lycopersicum

Directory of Open Access Journals (Sweden)

Miguel Angel eSalas-Marina

2015-02-01

Full Text Available Fungi belonging to the genus Trichoderma, commonly found in soil or colonizing plant roots, exert beneficial effects on plants, including the promotion of growth and the induction of resistance to disease. T. virens and T. atroviride secrete the proteins Sm1 and Epl1, respectively, which elicit local and systemic disease resistance in plants. In this work, we show that these fungi promote growth in tomato (Solanum lycopersicum plants. T. virens was more effective than T. atroviride in promoting biomass gain, and both fungi were capable of inducing systemic protection in tomato against Alternaria solani, Botrytis cinerea, and Pseudomonas syringae pv. tomato (Pst DC3000. Deletion (KO of epl1 in T. atroviride resulted in diminished systemic protection against A. solani and B. cinerea, whereas the T. virens sm1 KO strain was less effective in protecting tomato against Pst DC3000 and B. cinerea. Importantly, over-expression (OE of epl1 and sm1 led to an increase in disease resistance against all tested pathogens. Although the Trichoderma WT strains induced both systemic acquired resistance (SAR- and induced systemic resistance (ISR-related genes in tomato, inoculation of plants with OE and KO strains revealed that Epl1 and Sm1 play a minor role in the induction of these genes. However, we found that Epl1 and Sm1 induce the expression of a peroxidase and an α-dioxygenase encoding genes, respectively, which could be important for tomato protection by Trichoderma spp. Altogether, these observations indicate that colonization by beneficial and/or infection by pathogenic microorganisms dictates many of the outcomes in plants, which are more complex than previously thought.

Mutagenesis and breeding for disease resistance in capsicum

International Nuclear Information System (INIS)

Saccardo, F.; Sree Ramulu, K.

1977-01-01

The principal diseases, for which no sources have so far been found within the cultivars of Capsicum annuum in Italy, are caused by Verticillium dahliae, Phytophthora capsici and cucumber mosaic virus (CMV). The wild species C. pendulum, C. frutescens, C. chinense, C. chacoense, C. pubescens and C. eximium were analysed to find out if the sources for resistance to the three diseases are available. It was observed that particularly the species C. frutescens and C. chinense had good sources of resistance to V. dahliae and Ph. capsici. However, the occurrence of reproductive barriers between the wild and cultivated species appears to be a problem for the transfer of disease-resistant genes. For CMV, none of the wild species showed good resistance; so in this case a screening technique was set up using mutagenic agents to isolate resistant types in the prominent agronomic cultivars of C. annuum. Also, for V. dahliae and Ph. capsici, mutation screening techniques were set up to induce disease resistance character directly in the cultivars of C. annuum, without causing any changes in the most important agronomic characters of the cultivars. (author)

Enhanced resistance to stripe rust disease in transgenic wheat expressing the rice chitinase gene RC24.

Science.gov (United States)

Huang, Xuan; Wang, Jian; Du, Zhen; Zhang, Chen; Li, Lan; Xu, Ziqin

2013-10-01

Stripe rust is a devastating fungal disease of wheat worldwide which is primarily caused by Puccinia striiformis f. sp tritici. Transgenic wheat (Triticum aestivum L.) expressing rice class chitinase gene RC24 were developed by particle bombardment of immature embryos and tested for resistance to Puccinia striiformis f.sp tritici. under greenhouse and field conditions. Putative transformants were selected on kanamycin-containing media. Polymease chain reaction indicated that RC24 was transferred into 17 transformants obtained from bombardment of 1,684 immature embryos. Integration of RC24 was confirmed by Southern blot with a RC24-labeled probe and expression of RC24 was verified by RT-PCR. Nine transgenic T1 lines exhibited enhanced resistance to stripe rust infection with lines XN8 and BF4 showing the highest level of resistance. Southern blot hybridization confirmed the stable inheritance of RC24 in transgenic T1 plants. Resistance to stripe rust in transgenic T2 and T3 XN8 and BF4 plants was confirmed over two consecutive years in the field. Increased yield (27-36 %) was recorded for transgenic T2 and T3 XN8 and BF4 plants compared to controls. These results suggest that rice class I chitinase RC24 can be used to engineer stripe rust resistance in wheat.

New Technologies for Insect-Resistant and Herbicide-Tolerant Plants.

Science.gov (United States)

Lombardo, Luca; Coppola, Gerardo; Zelasco, Samanta

2016-01-01

The advent of modern molecular biology and recombinant DNA technology has resulted in a dramatic increase in the number of insect-resistant (IR) and herbicide-tolerant (HT) plant varieties, with great economic benefits for farmers. Nevertheless, the high selection pressure generated by control strategies for weed and insect populations has led to the evolution of herbicide and pesticide resistance. In the short term, the development of new techniques or the improvement of existing ones will provide further instruments to counter the appearance of resistant weeds and insects and to reduce the use of agrochemicals. In this review, we examine some of the most promising new technologies for developing IR and HT plants, such as genome editing and antisense technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bipolar resistive switching in different plant and animal proteins

KAUST Repository

Bag, A.; Hota, Mrinal Kanti; Mallik, Sandipan B.; Maì ti, Chinmay Kumar

2014-01-01

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.

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.

Genetics and molecular mapping of genes for race-specific all-stage resistance and non-race-specific high-temperature adult-plant resistance to stripe rust in spring wheat cultivar Alpowa.

Science.gov (United States)

Lin, F; Chen, X M

2007-05-01

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Growing resistant cultivars is the preferred control of the disease. The spring wheat cultivar 'Alpowa' has both race-specific, all-stage resistance and non-race-specific, high-temperature adult-plant (HTAP) resistances to stripe rust. To identify genes for the stripe rust resistances, Alpowa was crossed with 'Avocet Susceptible' (AVS). Seedlings of the parents, and F(1), F(2) and F(3) progeny were tested with races PST-1 and PST-21 of P. striiformis f. sp. tritici under controlled greenhouse conditions. Alpowa has a single partially dominant gene, designated as YrAlp, conferring all-stage resistance. Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) techniques were used to identify molecular markers linked to YrAlp. A linkage group of five RGAP markers and two SSR markers was constructed for YrAlp using 136 F(3) lines. Amplification of a set of nulli-tetrasomic Chinese Spring lines with RGAP markers Xwgp47 and Xwgp48 and the two SSR markers indicated that YrAlp is located on the short arm of chromosome 1B. To map quantitative trait loci (QTLs) for the non-race-specific HTAP resistance, the parents and 136 F(3) lines were tested at two sites near Pullman and one site near Mount Vernon, Washington, under naturally infected conditions. A major HTAP QTL was consistently detected across environments and was located on chromosome 7BL. Because of its chromosomal location and the non-race-specific nature of the HTAP resistance, this gene is different from previously described genes for adult-plant resistance, and is therefore designated Yr39. The gene contributed to 64.2% of the total variation of relative area under disease progress curve (AUDPC) data and 59.1% of the total variation of infection type data recorded at the heading-flowering stages. Two RGAP markers, Xwgp36 and Xwgp45 with the highest R (2) values

Radiation resistance of cable insulation and jacket materials for nuclear power plants

International Nuclear Information System (INIS)

Morita, Minoru; Kon, Shuji; Nishikawa, Ichiro

1978-01-01

The cables for use in nuclear power plants are required to satisfy the specific environmental resistance and excellent flame resistance as stipulated in IEEE Std. 383. The materials to be used to cables intended for this specific purpose of use must therefore be strictly tested so as to evaluate their flame resistance in addition to compliance with various environmental requirements, such as heat resistance, water-vapor resistance, and radiation resistance. This paper describes general information on radiation resistance and deterioration of various high-molecular materials, suggests the direction of efforts to be made to improve their properties including flame resistance of various rubber and plastic materials for cables to be used in nuclear power plants, and indicates the performance characteristics of such materials. (author)

Expression of self-complementary hairpin RNA under the control of the rolC promoter confers systemic disease resistance to plum pox virus without preventing local infection.

Science.gov (United States)

Pandolfini, Tiziana; Molesini, Barbara; Avesani, Linda; Spena, Angelo; Polverari, Annalisa

2003-06-25

Homology-dependent selective degradation of RNA, or post-transcriptional gene silencing (PTGS), is involved in several biological phenomena, including adaptative defense mechanisms against plant viruses. Small interfering RNAs mediate the selective degradation of target RNA by guiding a multicomponent RNAse. Expression of self-complementary hairpin RNAs within two complementary regions separated by an intron elicits PTGS with high efficiency. Plum pox virus (PPV) is the etiological agent of sharka disease in Drupaceae, although it can also be transmitted to herbaceous species (e.g. Nicotiana benthamiana). Once inside the plant, PPV is transmitted via plasmodesmata from cell to cell, and at longer distances, via phloem. The rolC promoter drives expression in phloem cells. RolC expression is absent in both epidermal and mesophyll cells. The aim of the present study was to confer systemic disease resistance without preventing local viral infection. In the ihprolC-PP197 gene (intron hair pin rolC PPV 197), a 197 bp sequence homologous to the PPV RNA genome (from base 134 to 330) was placed as two inverted repeats separated by the DNA sequence of the rolA intron. This hairpin construct is under the control of the rolC promoter.N. benthamiana plants transgenic for the ihprolC-PP197 gene contain siRNAs homologous to the 197 bp sequence. The transgenic progeny of ihprolC-PP197 plants are resistant to PPV systemic infection. Local infection is unaffected. Most (80%) transgenic plants are virus free and symptomless. Some plants (20%) contain virus in uninoculated apical leaves; however they show only mild symptoms of leaf mottling. PPV systemic resistance cosegregates with the ihprolC-PP197 transgene and was observed in progeny plants of all independent transgenic lines analyzed. SiRNAs of 23-25 nt homologous to the PPV sequence used in the ihprolC-PP197 construct were detected in transgenic plants before and after inoculation. Transitivity of siRNAs was observed in

Genome scanning for identification of resistance gene analogs (RGAs)

African Journals Online (AJOL)

Disease resistance in plants is a desirable economic trait. Many disease resistance genes from various plants have been cloned so far. The gene products of some of these can be distinguished by the presence of an N terminal nucleotide binding site and a C-terminal stretch of leucine-rich repeats. Oligonucleotides already ...

(Cucumis melo L.) cultivars to soil-borne plant pathogenic fungi in Iran

African Journals Online (AJOL)

ajl11

2012-10-30

Oct 30, 2012 ... resistance of melon cultivars to three important soil-borne plant pathogens found worldwide. Key words: Melon ... use of cultivars resistant to plant diseases is one of the ..... emerging disease of melons worldwide. Plant Dis.

Cadmium resistance in tobacco plants expressing the MuSI gene.

Science.gov (United States)

Kim, Young-Nam; Kim, Ji-Seoung; Seo, Sang-Gyu; Lee, Youngwoo; Baek, Seung-Woo; Kim, Il-Sup; Yoon, Ho-Sung; Kim, Kwon-Rae; Kim, Sun-Hyung; Kim, Kye-Hoon

2011-10-01

MuSI, a gene that corresponds to a domain that contains the rubber elongation factor (REF), is highly homologous to many stress-related proteins in plants. Since MuSI is up-regulated in the roots of plants treated with cadmium or copper, the involvement of MuSI in cadmium tolerance was investigated in this study. Escherichia coli cells overexpressing MuSI were more resistant to Cd than wild-type cells transfected with vector alone. MuSI transgenic plants were also more resistant to Cd. MuSI transgenic tobacco plants absorbed less Cd than wild-type plants. Cd translocation from roots to shoots was reduced in the transgenic plants, thereby avoiding Cd toxicity. The number of short trichomes in the leaves of wild-type tobacco plants was increased by Cd treatment, while this was unchanged in MuSI transgenic tobacco. These results suggest that MuSI transgenic tobacco plants have enhanced tolerance to Cd via reduced Cd uptake and/or increased Cd immobilization in the roots, resulting in less Cd translocation to the shoots.

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 ...

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 ...

Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

Science.gov (United States)

Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

2014-01-01

Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

Breeding of Yangfumai No.5 with multiple disease resistance

International Nuclear Information System (INIS)

He Zhentian; Chen Xiulan; Zhang Rong; Wang Jianhua; Wang Jinrong

2013-01-01

To control the damage of wheat yellow mosaic disease and powdery mildew, new wheat cultivar with high-yield, disease-resistant was bred. Yangfumai 9311 with yellow mosaic disease resistant was used as donor parent to backcross with recurrent parent Yangmai 11, and combined with conventional breeding techniques and irradiation methods, a new wheat variety Yangfumai No.5 was developed and registered in 2011. Yangfumai No.5 with resistance of yellow mosaic disease and powdery mildew is suitable to grow in the Yangtze River region. (authors)

Is the efficacy of biological control against plant diseases likely to be more durable than that of chemical pesticides?

Directory of Open Access Journals (Sweden)

Marc eBardin

2015-07-01

Full Text Available The durability of a control method for plant protection is defined as the persistence of its efficacy in space and time. It depends on (i the selection pressure exerted by it on populations of plant pathogens and (ii on the capacity of these pathogens to adapt to the control method. Erosion of effectiveness of conventional plant protection methods has been widely studied in the past. For example, apparition of resistance to chemical pesticides in plant pathogens or pests has been extensively documented. The durability of biological control has often been assumed to be higher than that of chemical control. Results concerning pest management in agricultural systems have shown that this assumption may not always be justified. Resistance of various pests to one or several toxins of Bacillus thuringensis and apparition of resistance of the codling moth Cydia pomonella to the Cydia pomonella granulovirus have, for example, been described. In contrast with the situation for pests, the durability of biological control of plant diseases has hardly been studied and no scientific reports proving the loss of efficiency of biological control agents against plant pathogens in practice has been published so far. Knowledge concerning the possible erosion of effectiveness of biological control is essential to ensure a durable efficacy of biological control agents on target plant pathogens. This knowledge will result in identifying risk factors that can foster the selection of strains of plant pathogens resistant to biological control agents. It will also result in identifying types of biological control agents with lower risk of efficacy loss i.e. modes of action of biological control agents that does not favor the selection of resistant isolates in natural populations of plant pathogens. An analysis of the scientific literature was then conducted to assess the potential for plant pathogens to become resistant to biological control agents.

Resistance in Cucumis sativus L. to Tetranychus urticae Koch

NARCIS (Netherlands)

Ponti, de O.M.B.

1980-01-01

Chapter 1
The role of plant breeding and particularly of host plant resistance in integrated control is discussed. Host plant resistance to insects and mites, especially to Tetranychus urticae is reviewed. A standard terminology for disease and pest

Salicylic Acid Is Involved in the Basal Resistance of Tomato Plants to Citrus Exocortis Viroid and Tomato Spotted Wilt Virus.

Science.gov (United States)

López-Gresa, M Pilar; Lisón, Purificación; Yenush, Lynne; Conejero, Vicente; Rodrigo, Ismael; Bellés, José María

2016-01-01

Tomato plants expressing the NahG transgene, which prevents accumulation of endogenous salicylic acid (SA), were used to study the importance of the SA signalling pathway in basal defence against Citrus Exocortis Viroid (CEVd) or Tomato Spotted Wilt Virus (TSWV). The lack of SA accumulation in the CEVd- or TSWV-infected NahG tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental Money Maker. Addition of acibenzolar-S-methyl, a benzothiadiazole (BTH), which activates the systemic acquired resistance pathway downstream of SA signalling, improves resistance of NahG tomato plants to CEVd and TSWV. CEVd and TSWV inoculation induced the accumulation of the hydroxycinnamic amides p-coumaroyltyramine, feruloyltyramine, caffeoylputrescine, and feruloylputrescine, and the defence related proteins PR1 and P23 in NahG plants earlier and with more intensity than in Money Maker plants, indicating that SA is not essential for the induction of these plant defence metabolites and proteins. In addition, NahG plants produced very high levels of ethylene upon CEVd or TSWV infection when compared with infected Money Maker plants, indicating that the absence of SA produced additional effects on other metabolic pathways. This is the first report to show that SA is an important component of basal resistance of tomato plants to both CEVd and TSWV, indicating that SA-dependent defence mechanisms play a key role in limiting the severity of symptoms in CEVd- and TSWV-infected NahG tomato plants.

Arabidopsis EF-Tu receptor enhances bacterial disease resistance in transgenic wheat.

Science.gov (United States)

Schoonbeek, Henk-Jan; Wang, Hsi-Hua; Stefanato, Francesca L; Craze, Melanie; Bowden, Sarah; Wallington, Emma; Zipfel, Cyril; Ridout, Christopher J

2015-04-01

Perception of pathogen (or microbe)-associated molecular patterns (PAMPs/MAMPs) by pattern recognition receptors (PRRs) is a key component of plant innate immunity. The Arabidopsis PRR EF-Tu receptor (EFR) recognizes the bacterial PAMP elongation factor Tu (EF-Tu) and its derived peptide elf18. Previous work revealed that transgenic expression of AtEFR in Solanaceae confers elf18 responsiveness and broad-spectrum bacterial disease resistance. In this study, we developed a set of bioassays to study the activation of PAMP-triggered immunity (PTI) in wheat. We generated transgenic wheat (Triticum aestivum) plants expressing AtEFR driven by the constitutive rice actin promoter and tested their response to elf18. We show that transgenic expression of AtEFR in wheat confers recognition of elf18, as measured by the induction of immune marker genes and callose deposition. When challenged with the cereal bacterial pathogen Pseudomonas syringae pv. oryzae, transgenic EFR wheat lines had reduced lesion size and bacterial multiplication. These results demonstrate that AtEFR can be transferred successfully from dicot to monocot species, further revealing that immune signalling pathways are conserved across these distant phyla. As novel PRRs are identified, their transfer between plant families represents a useful strategy for enhancing resistance to pathogens in crops. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Predicting spring barley yield from variety-specific yield potential, disease resistance and straw length, and from environment-specific disease loads and weed pressure

DEFF Research Database (Denmark)

Østergård, Hanne; Kristensen, Kristian; Pinnschmidt, Hans O.

2008-01-01

For low-input crop production, well-characterised varieties increase the possibilities of managing diseases and weeds. This analysis aims at developing a framework for analyzing grain yield using external varietal information about disease resistance, weed competitiveness and yield potential and ...... growth habit. Higher grain yield was thus predicted for taller plants under weed pressure. The results are discussed in relation to the model framework, impact of the considered traits and use of information from conventional variety testing in organic cropping systems....

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

of these interactions, we tested how genetically divergent resistant and susceptible plants are, using microsatellite markers. To test whether they are reproductively fully compatible, resistant and susceptible plants were grown intermixed in an outdoor experiment, and the paternity of open-pollinated offspring......Co-evolution between herbivores and plants is believed to be one of the processes creating Earth’s biodiversity. However, it is difficult to disentangle to what extent diversification is really driven by herbivores or by other historical-geographical processes like allopatric isolation....... 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...

Contrasting effects of specialist and generalist herbivores on resistance evolution in invasive plants.

Science.gov (United States)

Zhang, Zhijie; Pan, Xiaoyun; Blumenthal, Dana; van Kleunen, Mark; Liu, Mu; Li, Bo

2018-04-01

Invasive alien plants are likely to be released from specialist herbivores and at the same time encounter biotic resistance from resident generalist herbivores in their new ranges. The Shifting Defense hypothesis predicts that this will result in evolution of decreased defense against specialist herbivores and increased defense against generalist herbivores. To test this, we performed a comprehensive meta-analysis of 61 common garden studies that provide data on resistance and/or tolerance for both introduced and native populations of 32 invasive plant species. We demonstrate that introduced populations, relative to native populations, decreased their resistance against specialists, and increased their resistance against generalists. These differences were significant when resistance was measured in terms of damage caused by the herbivore, but not in terms of performance of the herbivore. Furthermore, we found the first evidence that the magnitude of resistance differences between introduced and native populations depended significantly on herbivore origin (i.e., whether the test herbivore was collected from the native or non-native range of the invasive plant). Finally, tolerance to generalists was found to be higher in introduced populations, while neither tolerance to specialists nor that to simulated herbivory differed between introduced and native plant populations. We conclude that enemy release from specialist herbivores and biotic resistance from generalist herbivores have contrasting effects on resistance evolution in invasive plants. Our results thus provide strong support for the Shifting Defense hypothesis. © 2018 by the Ecological Society of America.

Inheritance of black sigatoka disease resistance in plantain-banana (Musa spp.) hybrids.

Science.gov (United States)

Ortiz, R; Vuylsteke, D

1994-10-01

Black sigatoka (Mycosphaerella fijiensis Morelet), an airborne fungal leaf-spot disease, is a major constraint to plantain and banana (Musa spp.) production world-wide. Gaining further knowledge of the genetics of host-plant resistance will enhance the development of resistant cultivars, which is considered to be the most appropriate means to achieve stable production. Genetic analysis was conducted on 101 euploid (2x, 3x and 4x) progenies, obtained from crossing two susceptible triploid plantain cultivars with the resistant wild diploid banana 'Calcutta 4'. Segregating progenies, and a susceptible reference plantain cultivar, were evaluated over 2 consecutive years. Three distinct levels of host response to black sigatoka were defined as follows: susceptible ( 10). Segregation ratios for resistance at the 2x level fitted a genetic model having one major recessive resistance allele (bs 1) and two independent alleles with additive effects (bsr 2 and bsr 3). A similar model explains the results at the 4x level assuming that the favourable resistance alleles have a dosage effect when four copies of them are present in their respective loci (bs i (4) ). The proposed model was further validated by segregation data of S 1 progenies. Mechanisms of black sigatoka resistance are discussed in relation to the genetic model.

Influence of stripe rust infection on the photosynthetic characteristics and antioxidant system of susceptible and resistant wheat cultivars at the adult plant stage.

Science.gov (United States)

Chen, Yang-Er; Cui, Jun-Mei; Su, Yan-Qiu; Yuan, Shu; Yuan, Ming; Zhang, Huai-Yu

2015-01-01

Wheat stripe rust (Puccinia striiformis f. sp. tritici, Pst), is one of the most serious diseases of wheat (Triticum aestivum L.) worldwide. To gain a better understanding of the protective mechanism against stripe rust at the adult plant stage, the differences in photosystem II and antioxidant enzymatic systems between susceptible and resistant wheat in response to stripe rust disease (P. striiformis) were investigated. We found that chlorophyll fluorescence and the activities of the antioxidant enzymes were higher in resistant wheat than in susceptible wheat after stripe rust infection. Compared with the susceptible wheat, the resistant wheat accumulated a higher level of D1 protein and a lower level of reactive oxygen species after infection. Furthermore, our results demonstrate that D1 and light-harvesting complex II (LHCII) phosphorylation are involved in the resistance to stripe rust in wheat. The CP29 protein was phosphorylated under stripe rust infection, like its phosphorylation in other monocots under environmental stresses. More extensive damages occur on the thylakoid membranes in the susceptible wheat compared with the resistant wheat. The findings provide evidence that thylakoid protein phosphorylation and antioxidant enzyme systems play important roles in plant responses and defense to biotic stress.

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.

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

International Nuclear Information System (INIS)

Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L.D.; Anuntalabhochai, S.

2013-01-01

Highlights: •N-ion beam bombarded Thai jasmine rice seeds to induce mutation. •Mutants with blast-disease resistance and high yield were screened. •Gene involved in the blast-disease resistance was analyzed. •The gene responsible for the resistance was linked to Spotted leaf protein 11. -- Abstract: Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60–80 keV to a beam fluence range of 2 × 10 16 –2 × 10 17 ions/cm 2 . The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 10 6 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11)

The resistance response of sunflower genotypes to black stem disease under controlled conditions

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Reza DARVISHZADEH

2010-09-01

Full Text Available Phoma black stem, caused by Phoma macdonaldii, is one of the most important diseases of sunflower in the world. The sources of resistance to Phoma black stem were investigated. A total of 184 genotypes, including some recombinant inbred lines (RILs, several M6 mutant lines obtained by gamma irradiation of seed of the genotype AS 613, and other genotypes from different countries, were evaluated against an aggressive French isolate (MP6 in controlled conditions. The study was carried out in a randomized complete block design with three replicates. Each replicate consisted of 10–12 seedlings. Twenty μL of spore suspension (106 pycnidiospores mL-1 were deposited on the intersection of the cotyledon petiole and the hypocotyl of sunflower plantlets at the two-leaf stage. The percentage of the area exhibiting disease symptoms was scored on the two cotyledon petioles of each of the plantlets three, five and seven days after inoculation. The disease progress rate (rd, as the slope of the regression line for disease severity against time, was also calculated. Analysis of variance detected significant differences among sunflower genotypes for disease severity 7 days after inoculation,as well as for the disease progress rate. A strong correlation (r=0.96, P<0.01 was found between disease severity 7 days after inoculation and the disease progress rate. The inbred lines F1250/03 (origin: Hungary, M5-54-1, M6-862-1 (mutant lines, SDR 18 (origin: USA and two wild Helianthus accessions, 1012 Nebraska and 211 Illinois, (wild type were highly resistant to Phoma black stem. These findings will assist breeders in choosing parent plants for breeding durable resistance to Phoma black stem.

Diuretics Prime Plant Immunity in Arabidopsis thaliana

Science.gov (United States)

Noutoshi, Yoshiteru; Ikeda, Mika; Shirasu, Ken

2012-01-01

Plant activators are agrochemicals that activate the plant immune system, thereby enhancing disease resistance. Due to their prophylactic and durable effects on a wide spectrum of diseases, plant activators can provide synergistic crop protection when used in combination with traditional pest controls. Although plant activators have achieved great success in wet-rice farming practices in Asia, their use is still limited. To isolate novel plant activators applicable to other crops, we screened a chemical library using a method that can selectively identify immune-priming compounds. Here, we report the isolation and characterization of three diuretics, bumetanide, bendroflumethiazide and clopamide, as immune-priming compounds. These drugs upregulate the immunity-related cell death of Arabidopsis suspension-cultured cells induced with an avirulent strain of Pseudomonas syringae pv. tomato in a concentration-dependent manner. The application of these compounds to Arabidopsis plants confers disease resistance to not only the avirulent but also a virulent strain of the pathogen. Unlike salicylic acid, an endogenous phytohormone that governs disease resistance in response to biotrophic pathogens, the three diuretic compounds analyzed here do not induce PR1 or inhibit plant growth, showing potential as lead compounds in a practical application. PMID:23144763

Digital Gene Expression Analysis to Screen Disease Resistance-Relevant Genes from Leaves of Herbaceous Peony (Paeonia lactiflora Pall. Infected by Botrytis cinerea.

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Saijie Gong

Full Text Available Herbaceous peony (Paeonia lactiflora Pall. is a well-known traditional flower in China and is widely used for landscaping and garden greening due to its high ornamental value. However, disease spots usually appear after the flowering of the plant and may result in the withering of the plant in severe cases. This study examined the disease incidence in an herbaceous peony field in the Yangzhou region, Jiangsu Province. Based on morphological characteristics and molecular data, the disease in this area was identified as a gray mold caused by Botrytis cinerea. Based on previously obtained transcriptome data, eight libraries generated from two herbaceous peony cultivars 'Zifengyu' and 'Dafugui' with different susceptibilities to the disease were then analyzed using digital gene expression profiling (DGE. Thousands of differentially expressed genes (DEGs were screened by comparing the eight samples, and these genes were annotated using the Gene ontology (GO and Kyoto encyclopedia of genes and genomes (KEGG database. The pathways related to plant-pathogen interaction, secondary metabolism synthesis and antioxidant system were concentrated, and 51, 76, and 13 disease resistance-relevant candidate genes were identified, respectively. The expression patterns of these candidate genes differed between the two cultivars: their expression of the disease-resistant cultivar 'Zifengyu' sharply increased during the early stages of infection, while it was relatively subdued in the disease-sensitive cultivar 'Dafugui'. A selection of ten candidate genes was evaluated by quantitative real-time PCR (qRT-PCR to validate the DGE data. These results revealed the transcriptional changes that took place during the interaction of herbaceous peony with B. cinerea, providing insight into the molecular mechanisms of host resistance to gray mold.

Mutagenesis and haploid culture for disease resistance in Brassica napus

Energy Technology Data Exchange (ETDEWEB)

MacDonald, M V; Ahmad, I; Ingram, D S [Botany School, University of Cambridge, Cambridge (United Kingdom)

1990-01-01

Full text: Most winter oilseed rape cultivars share parentage and therefore show little genetic diversity. There is no known resistance to Alternaria spp. in oilseed rape or in any related Brassica species. Experiments with tissue culture yielded only transient, non-genetic resistance. Therefore, mutagenesis may be used to generate heritable resistance to Alternaria spp. Gamma irradiation was applied to seeds of 'Bienvenue', secondary embryoids of cvs 'Primor' and 'Rapora', and buds of cvs 'Primor' and 'Ariana'. Isolated microspores from cv 'Ariana' and rapid cycling B. napus were also treated. The doses used ranged from 0-100 Gy for isolated microspores and buds, up to 600 Gy for seeds and 960 Gy for secondary embryoids. EMS was used to treat seeds of line WRG-42 (supplied by Nickersons RPB) and microspores of cv 'Bienvenue' and rapid cycling B. napus. Seeds were treated with up to 2.0% EMS for 0.2 h. before plating them on the culture medium. Seed irradiation up to 600 Gy did not reduce germination. M{sub 1} and M{sub 2} progenies were tested both in the laboratory and in field trials, and none of these were found to be resistant to Alternaria. However, considerable variation for other characters was observed. Haploid cultures from these plants were extremely difficult to regenerate, and for this reason no regenerant plants have been tested for resistance. For irradiated secondary embryoids the regeneration capacity decreased with increasing dose. Regenerated plants have been tested for resistance to Alternaria, but stable resistance was not observed. Haploid cultures were obtained from irradiated buds, using both anther and microspore culture. Low irradiation treatment was beneficial to developing embryoids. Some regenerants have been obtained from EMS treated microspores and seeds. Four plants have repeatedly given increased levels of resistance to A. brassicicola, and progenies are being tested to determine the genetic nature of the resistance. (author)

Mutagenesis and haploid culture for disease resistance in Brassica napus

International Nuclear Information System (INIS)

MacDonald, M.V.; Ahmad, I.; Ingram, D.S.

1990-01-01

Full text: Most winter oilseed rape cultivars share parentage and therefore show little genetic diversity. There is no known resistance to Alternaria spp. in oilseed rape or in any related Brassica species. Experiments with tissue culture yielded only transient, non-genetic resistance. Therefore, mutagenesis may be used to generate heritable resistance to Alternaria spp. Gamma irradiation was applied to seeds of 'Bienvenue', secondary embryoids of cvs 'Primor' and 'Rapora', and buds of cvs 'Primor' and 'Ariana'. Isolated microspores from cv 'Ariana' and rapid cycling B. napus were also treated. The doses used ranged from 0-100 Gy for isolated microspores and buds, up to 600 Gy for seeds and 960 Gy for secondary embryoids. EMS was used to treat seeds of line WRG-42 (supplied by Nickersons RPB) and microspores of cv 'Bienvenue' and rapid cycling B. napus. Seeds were treated with up to 2.0% EMS for 0.2 h. before plating them on the culture medium. Seed irradiation up to 600 Gy did not reduce germination. M 1 and M 2 progenies were tested both in the laboratory and in field trials, and none of these were found to be resistant to Alternaria. However, considerable variation for other characters was observed. Haploid cultures from these plants were extremely difficult to regenerate, and for this reason no regenerant plants have been tested for resistance. For irradiated secondary embryoids the regeneration capacity decreased with increasing dose. Regenerated plants have been tested for resistance to Alternaria, but stable resistance was not observed. Haploid cultures were obtained from irradiated buds, using both anther and microspore culture. Low irradiation treatment was beneficial to developing embryoids. Some regenerants have been obtained from EMS treated microspores and seeds. Four plants have repeatedly given increased levels of resistance to A. brassicicola, and progenies are being tested to determine the genetic nature of the resistance. (author)

Comparisons of protein profiles of beech bark disease resistant and susceptible American beech (Fagus grandifolia)

Science.gov (United States)

2013-01-01

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 development in stands. Early

Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

Science.gov (United States)

Somerville, Chris R [Portola Valley, CA; Scheible, Wolf [Golm, DE

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.

Resistance in Cucumis sativus L. to Tetranychus urticae Koch

OpenAIRE

Ponti, de, O.M.B.

1980-01-01

Chapter 1
The role of plant breeding and particularly of host plant resistance in integrated control is discussed. Host plant resistance to insects and mites, especially to Tetranychus urticae is reviewed. A standard terminology for disease and pest resistance is recommended.

Chapter 2
The relationship between the twospotted spider mite and cucumber has been studied on plants and on leaf disks of a number of varieties with different...

Bacterial disease management: challenges, experience, innovation and future prospects: Challenges in Bacterial Molecular Plant Pathology.

Science.gov (United States)

Sundin, George W; Castiblanco, Luisa F; Yuan, Xiaochen; Zeng, Quan; Yang, Ching-Hong

2016-12-01

Plant diseases caused by bacterial pathogens place major constraints on crop production and cause significant annual losses on a global scale. The attainment of consistent effective management of these diseases can be extremely difficult, and management potential is often affected by grower reliance on highly disease-susceptible cultivars because of consumer preferences, and by environmental conditions favouring pathogen development. New and emerging bacterial disease problems (e.g. zebra chip of potato) and established problems in new geographical regions (e.g. bacterial canker of kiwifruit in New Zealand) grab the headlines, but the list of bacterial disease problems with few effective management options is long. The ever-increasing global human population requires the continued stable production of a safe food supply with greater yields because of the shrinking areas of arable land. One major facet in the maintenance of the sustainability of crop production systems with predictable yields involves the identification and deployment of sustainable disease management solutions for bacterial diseases. In addition, the identification of novel management tactics has also come to the fore because of the increasing evolution of resistance to existing bactericides. A number of central research foci, involving basic research to identify critical pathogen targets for control, novel methodologies and methods of delivery, are emerging that will provide a strong basis for bacterial disease management into the future. Near-term solutions are desperately needed. Are there replacement materials for existing bactericides that can provide effective disease management under field conditions? Experience should inform the future. With prior knowledge of bactericide resistance issues evolving in pathogens, how will this affect the deployment of newer compounds and biological controls? Knowledge is critical. A comprehensive understanding of bacterial pathosystems is required to not

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...

Plants used to treat skin diseases

Science.gov (United States)

Tabassum, Nahida; Hamdani, Mariya

2014-01-01

Skin diseases are numerous and a frequently occurring health problem affecting all ages from the neonates to the elderly and cause harm in number of ways. Maintaining healthy skin is important for a healthy body. Many people may develop skin diseases that affect the skin, including cancer, herpes and cellulitis. Some wild plants and their parts are frequently used to treat these diseases. The use of plants is as old as the mankind. Natural treatment is cheap and claimed to be safe. It is also suitable raw material for production of new synthetic agents. A review of some plants for the treatment of skin diseases is provided that summarizes the recent technical advancements that have taken place in this area during the past 17 years. PMID:24600196

Analysis of Clonostachys rosea-induced resistance to tomato gray mold disease in tomato leaves.

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Liana Dalcantara Ongouya Mouekouba

Full Text Available Tomato gray mold disease, caused by Botrytis cinerea, is a serious disease in tomato. Clonostachys rosea is an antagonistic microorganism to B. cinerea. To investigate the induced resistance mechanism of C. rosea, we examined the effects of these microorganisms on tomato leaves, along with changes in the activities of three defense enzymes (PAL, PPO, GST, second messengers (NO, H2O2, O2(- and phytohormones (IAA, ABA, GA3, ZT, MeJA, SA and C2H4. Compared to the control, all treatments induced higher levels of PAL, PPO and GST activity in tomato leaves and increased NO, SA and GA3 levels. The expression of WRKY and MAPK, two important transcription factors in plant disease resistance, was upregulated in C. rosea- and C. rosea plus B. cinerea-treated samples. Two-dimensional gel electrophoresis analysis showed that two abundant proteins were present in the C. rosea plus B. cinerea-treated samples but not in the other samples. These proteins were determined (by mass spectrum analysis to be LEXYL2 (β-xylosidase and ATP synthase CF1 alpha subunit. Therefore, C. rosea plus B. cinerea treatment induces gray mold resistance in tomato. This study provides a basis for elucidating the mechanism of C. rosea as a biocontrol agent.

Salicylic Acid Is Involved in the Basal Resistance of Tomato Plants to Citrus Exocortis Viroid and Tomato Spotted Wilt Virus.

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M Pilar López-Gresa

Full Text Available Tomato plants expressing the NahG transgene, which prevents accumulation of endogenous salicylic acid (SA, were used to study the importance of the SA signalling pathway in basal defence against Citrus Exocortis Viroid (CEVd or Tomato Spotted Wilt Virus (TSWV. The lack of SA accumulation in the CEVd- or TSWV-infected NahG tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental Money Maker. Addition of acibenzolar-S-methyl, a benzothiadiazole (BTH, which activates the systemic acquired resistance pathway downstream of SA signalling, improves resistance of NahG tomato plants to CEVd and TSWV. CEVd and TSWV inoculation induced the accumulation of the hydroxycinnamic amides p-coumaroyltyramine, feruloyltyramine, caffeoylputrescine, and feruloylputrescine, and the defence related proteins PR1 and P23 in NahG plants earlier and with more intensity than in Money Maker plants, indicating that SA is not essential for the induction of these plant defence metabolites and proteins. In addition, NahG plants produced very high levels of ethylene upon CEVd or TSWV infection when compared with infected Money Maker plants, indicating that the absence of SA produced additional effects on other metabolic pathways. This is the first report to show that SA is an important component of basal resistance of tomato plants to both CEVd and TSWV, indicating that SA-dependent defence mechanisms play a key role in limiting the severity of symptoms in CEVd- and TSWV-infected NahG tomato plants.

Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

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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.

A specialist root herbivore reduces plant resistance and uses an induced plant volatile to aggregate in a density dependent manner

Science.gov (United States)

1. Leaf-herbivore attack often triggers induced resistance in plants. However, certain specialist herbivores can also take advantage of the induced metabolic changes. In some cases, they even manipulate plant resistance, leading to a phenomenon called induced susceptibility. Compared to above-ground...

Sites of infection by pythium species in rice seedlings and effects of plant age and water depth on disease development.

Science.gov (United States)

Chun, S C; Schneider, R W

1998-12-01

ABSTRACT Seedling disease, caused primarily by several species of Pythium, is one of the major constraints to water-seeded rice production in Louisiana. The disease, also known as water-mold disease, seed rot, and seedling damping-off, causes stand reductions and growth abnormalities. In severe cases, fields must be replanted, which may result in delayed harvests and reduced yields. To develop more effective disease management tactics including biological control, this study was conducted primarily to determine sites of infection in seeds and seedlings; effect of plant age on susceptibility to P. arrhenomanes, P. myriotylum, and P. dissotocum; and minimum exposure times required for infection and seedling death. In addition, the effect of water depth on seedling disease was investigated. Infection rates of seed embryos were significantly higher than those of endosperms for all three Pythium spp. The development of roots from dry-seeded seedlings was significantly reduced by P. arrhenomanes and P. myriotylum at 5 days after planting compared with that of roots from noninoculated controls. Susceptibility of rice to all three species was sharply reduced within 2 to 6 days after planting, and seedlings were completely resistant at 8 days after planting. There was a steep reduction in emergence through the flood water, relative to the noninoculated control, following 2 to 3 days of exposure to inoculum of P. arrhenomanes and P. myriotylum. In contrast, P. dissotocum was much less virulent and required longer exposure times to cause irreversible seedling damage. Disease incidence was higher when seeds were planted into deeper water, implying that seedlings become resistant after they emerge through the flood water. These results suggest that disease control tactics including flood water management need to be employed for a very short period of time after planting. Also, given that the embryo is the primary site of infection and it is susceptible for only a few days, the

Expression of self-complementary hairpin RNA under the control of the rolC promoter confers systemic disease resistance to plum pox virus without preventing local infection

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Spena Angelo

2003-06-01

Full Text Available Abstract Background Homology-dependent selective degradation of RNA, or post-transcriptional gene silencing (PTGS, is involved in several biological phenomena, including adaptative defense mechanisms against plant viruses. Small interfering RNAs mediate the selective degradation of target RNA by guiding a multicomponent RNAse. Expression of self-complementary hairpin RNAs within two complementary regions separated by an intron elicits PTGS with high efficiency. Plum pox virus (PPV is the etiological agent of sharka disease in Drupaceae, although it can also be transmitted to herbaceous species (e.g. Nicotiana benthamiana. Once inside the plant, PPV is transmitted via plasmodesmata from cell to cell, and at longer distances, via phloem. The rolC promoter drives expression in phloem cells. RolC expression is absent in both epidermal and mesophyll cells. The aim of the present study was to confer systemic disease resistance without preventing local viral infection. Results In the ihprolC-PP197 gene (intron hair pin rolC PPV 197, a 197 bp sequence homologous to the PPV RNA genome (from base 134 to 330 was placed as two inverted repeats separated by the DNA sequence of the rolA intron. This hairpin construct is under the control of the rolC promoter.N. benthamiana plants transgenic for the ihprolC-PP197 gene contain siRNAs homologous to the 197 bp sequence. The transgenic progeny of ihprolC-PP197 plants are resistant to PPV systemic infection. Local infection is unaffected. Most (80% transgenic plants are virus free and symptomless. Some plants (20% contain virus in uninoculated apical leaves; however they show only mild symptoms of leaf mottling. PPV systemic resistance cosegregates with the ihprolC-PP197 transgene and was observed in progeny plants of all independent transgenic lines analyzed. SiRNAs of 23–25 nt homologous to the PPV sequence used in the ihprolC-PP197 construct were detected in transgenic plants before and after inoculation

Non-Thermal Plasma Treatment Diminishes Fungal Viability and Up-Regulates Resistance Genes in a Plant Host

Science.gov (United States)

Panngom, Kamonporn; Lee, Sang Hark; Park, Dae Hoon; Sim, Geon Bo; Kim, Yong Hee; Uhm, Han Sup; Park, Gyungsoon; Choi, Eun Ha

2014-01-01

Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance. PMID:24911947

Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

Directory of Open Access Journals (Sweden)

Kamonporn Panngom

Full Text Available Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

3. General principles of assessing seismic resistance of technological equipment of nuclear power plants

International Nuclear Information System (INIS)

1983-01-01

The evaluation of the seismic resistance of technological equipment is performed by computation, experimental trial, possibly by combining both methods. Existing and prepared standards in the field of seismic resistance of nuclear power plants are mentioned. Accelerograms and response spectra of design-basis earhtquake and maximum credible earthquake serve as the basic data for evaluating seismic resistance. The nuclear power plant in Mochovce will be the first Czechoslovak nuclear power plant with so-called partially seismic design. The problem of dynamic interaction of technological equipment and nuclear power plant systems with a bearing structure is discussed. (E.F.)

Testing of disease-resistance of pokeweed antiviral protein gene ...

African Journals Online (AJOL)

Transformation of pokeweed antiviral protein gene (PAP) into plants was shown to improve plant resistance to several viruses or fungi pathogens with no much negative effect on plant growth. The non-virulent defective PAP inhibits only the virus but does not interfere with the host. A non-virulent defective PAP gene ...

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.

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

Energy Technology Data Exchange (ETDEWEB)

Mahadtanapuk, S. [School of Agriculture and Natural Resources, University of Phayao, Phayao 56000 (Thailand); Teraarusiri, W. [Central Laboratory, University of Phayao, Phayao 56000 (Thailand); Phanchaisri, B. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@frnf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Anuntalabhochai, S., E-mail: burinka@hotmail.com [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-07-15

Highlights: •N-ion beam bombarded Thai jasmine rice seeds to induce mutation. •Mutants with blast-disease resistance and high yield were screened. •Gene involved in the blast-disease resistance was analyzed. •The gene responsible for the resistance was linked to Spotted leaf protein 11. -- Abstract: Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60–80 keV to a beam fluence range of 2 × 10{sup 16}–2 × 10{sup 17} ions/cm{sup 2}. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 10{sup 6} spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11)

Host-plant-mediated effects of Nadefensin on herbivore and pathogen resistance in Nicotiana attenuata

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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

Transgenerational Effects Alter Plant Defense and Resistance in Nature

Science.gov (United States)

Colicchio, Jack

2017-01-01

Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defense. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defense for Mimulus guttatus. After establishing the relationship between trichomes and herbivory, I test for transgenerational effects of wounding on trichome density and herbivore resistance. Patterns of inter-annual variation in herbivore density and the high cost of plant defense makes plant-herbivore interactions a system in which transgenerational phenotypic plasticity (TPP) is apt to evolve. Here, I demonstrate that parental damage alters offspring trichome density and herbivore resistance in nature. Moreover, this response varies between populations. This is among the first studies to demonstrate that TPP contributes to variation in nature, and also suggests that selection can modify TPP in response to local conditions. PMID:28102915

Comparative transcriptome proifling of two maize near-isogenic lines differing in the allelic state for bacterial brown spot disease resistance

Institute of Scientific and Technical Information of China (English)

WU Xiao-jun; Xu Li; ZHAO Pan-feng; LI Na; WU Lei; HE Yan; WANG Shou-cai

2015-01-01

The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hal (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated tran-scriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufifcient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identiifed to have signiifcantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveil ance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were deifned, providing the repertoire of candidate genes for further functional characterization and identiifcation of their regulation patterns during pathogen infection.

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

Wheat transcription factor TaWRKY70 is positively involved in high-temperature seedling-plant resistance to Puccinia striiformis f. sp. tritici

Science.gov (United States)

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating disease of wheat (Triticum aestivum) worldwide. Wheat high-temperature seedling-plant (HTSP) resistance to Pst is non-race-specific and durable. WRKY transcription factors have proven to play important roles in ...

Genome editing of the disease susceptibility gene CsLOB1 in citrus confers resistance to citrus canker.

Science.gov (United States)

Jia, Hongge; Zhang, Yunzeng; Orbović, Vladimir; Xu, Jin; White, Frank F; Jones, Jeffrey B; Wang, Nian

2017-07-01

Citrus is a highly valued tree crop worldwide, while, at the same time, citrus production faces many biotic challenges, including bacterial canker and Huanglongbing (HLB). Breeding for disease-resistant varieties is the most efficient and sustainable approach to control plant diseases. Traditional breeding of citrus varieties is challenging due to multiple limitations, including polyploidy, polyembryony, extended juvenility and long crossing cycles. Targeted genome editing technology has the potential to shorten varietal development for some traits, including disease resistance. Here, we used CRISPR/Cas9/sgRNA technology to modify the canker susceptibility gene CsLOB1 in Duncan grapefruit. Six independent lines, D LOB 2, D LOB 3, D LOB 9, D LOB 10, D LOB 11 and D LOB 12, were generated. Targeted next-generation sequencing of the six lines showed the mutation rate was 31.58%, 23.80%, 89.36%, 88.79%, 46.91% and 51.12% for D LOB 2, D LOB 3, D LOB 9, D LOB 10, D LOB 11 and D LOB 12, respectively, of the cells in each line. D LOB 2 and D LOB 3 showed canker symptoms similar to wild-type grapefruit, when inoculated with the pathogen Xanthomonas citri subsp. citri (Xcc). No canker symptoms were observed on D LOB 9, D LOB 10, D LOB 11 and D LOB 12 at 4 days postinoculation (DPI) with Xcc. Pustules caused by Xcc were observed on D LOB 9, D LOB 10, D LOB 11 and D LOB 12 in later stages, which were much reduced compared to that on wild-type grapefruit. The pustules on D LOB 9 and D LOB 10 did not develop into typical canker symptoms. No side effects and off-target mutations were detected in the mutated plants. This study indicates that genome editing using CRISPR technology will provide a promising pathway to generate disease-resistant citrus varieties. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Method for increasing the resistance of a plant or a part thereof to a pathogen, method for screening the resistance of a plant or part thereof to a pathogen, and use thereof

OpenAIRE

Wit, de, P.; Stergiopoulos, I.; Kema, G.H.J.

2011-01-01

(EN)The present invention relates to the field of plant biotechnology. More in particular, the present invention relates to methods for increasing the resistance of a plant or part thereof that is susceptible to infection with a pathogen comprising an ortholog of the Avr4 protein of Cladosporium fulvum, wherein said plant is not a tomato or tobacco plant. The invention also relates to methods for screening the resistance of a plant or a part thereof to at least one pathogen, wherein said path...

Bio-based resistance inducers for sustainable plant protection against pathogens

Czech Academy of Sciences Publication Activity Database

Burketová, Lenka; Trdá, Lucie; Ott, P.G.; Valentová, O.

2015-01-01

Roč. 33, č. 6 (2015), s. 994-1004 ISSN 0734-9750 R&D Projects: GA MŠk(CZ) LD14056 Institutional support: RVO:61389030 Keywords : Induced resistance * Elicitor * Chitosan Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 9.848, year: 2015

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

Genetic and physical analysis of a YAC contig spannig 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.J.F.; Hille, J.; Nijkamp, H.J.J.

1999-01-01

The Alternaria in 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

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

A maize resistance gene functions against bacterial streak disease in rice.

Science.gov (United States)

Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

2005-10-25

Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, which causes bacterial streak disease. Bacterial streak is an important disease of rice in Asia, and no simply inherited sources of resistance have been identified in rice. Although X. o. pv. oryzicola does not cause disease on maize, we identified a maize gene, Rxo1, that conditions a resistance reaction to a diverse collection of pathogen strains. Surprisingly, Rxo1 also controls resistance to the unrelated pathogen Burkholderia andropogonis, which causes bacterial stripe of sorghum and maize. The same gene thus controls resistance reactions to both pathogens and nonpathogens of maize. Rxo1 has a nucleotide-binding site-leucine-rich repeat structure, similar to many previously identified R genes. Most importantly, Rxo1 functions after transfer as a transgene to rice, demonstrating the feasibility of nonhost R gene transfer between cereals and providing a valuable tool for controlling bacterial streak disease.

Improvement of garlic resistance to white rot disease and its productivity and storability using gamma radiation

International Nuclear Information System (INIS)

Al-Safadi, B.; Mir Ali, N.; Arabi, M.I.D.

1999-01-01

A mutation program was conducted to improve garlic (Allium sativum) resistance to white rot (Sclerotium cepivorum) and to improve its storability under natural conditions. Cloves of two local garlic cultivars (Kisswany and Yabroudy) were irradiated with gamma ray doses 4, 5, 6 and 7 gray. The cloves were then planted in the the field and plants were advanced for 4 generations in order to isolate mutations in stable form. The results indicated that the cultivar Yabroudy was more sensitive to gamma irradiation than Kisswany. Rate of morphological mutants increased with increasing gamma ray dosage. Selection pressure against white rot disease was applied starting in the second generation by adding infected garlic leaves to the soil. In the third and fourth generations, however, full selection pressure was applied by inoculating the cloves with the fungus sclerotic and planting them in a soil previously planted with infected garlic plants. Healthy garlic bulbs were harvested and stored under natural conditions and then planted to obtain the next generation. By the end of the fourth generation, we have been able to improve garlic resistance to white rot disease and its storability. Twenty four mutant lines from each garlic cultivar have been selected. Out of the selected lines, twelve lines from cultivar Kisswany had only 3% infection percentage as compared to 29% in the control, and twelve lines from cultivar Yabroudy had less than 5% infection percentage as compared to 20% in the control. Also, we have been able to improve storability under natural conditions. Weight loss during storage decreased from 8.25% in the control to only 4% in some Kisswany lines and from 10% to 3% in some Yabroudy lines. However, we have not been able to increase the bulb weight over the control but the weights of the selected lines were comparable to those of the control. (authors)

Improvement of garlic resistance to white rot disease and its productivity and storability using gamma radiation

International Nuclear Information System (INIS)

Al-Safadi, B.; Mir Ali, N.; Arabi, M. I. D.

1998-12-01

A mutation program was conducted to improve garlic (Allium sativum) resistance to white rot (Sclerotium cepivorum) and to improve its storability under natural conditions. Cloves of two local garlic cultivars (Kisswany and Yabroudy) were irradiated with gamma ray doses 4, 5, 6, and 7 gray. The cloves were then planted in the field and plants were advanced for 4 generations in order to isolate mutations in stable form. The results indicated that the cultivar Yabroudy was more sensitive to gamma irradiation than Kisswany. Rate of morphological mutants increased with increasing gamma ray dosage. Selection pressure against white rot disease was applied starting in the second generation by adding infected garlic leaves to the soil. In the third and fourth generations, however, full selection pressure was applied by inoculating the cloves with the fungus sclerotia and planting them in a soil previously planted with infected garlic plants. healthy garlic bulbs were harvested and stored under natural conditions and then planted to obtain the next generation. By the end of the fourth generation, we have been able to improve garlic resistance to white rot disease and its storability. Twenty four mutant lines from each garlic cultivar have been selected. Out of the selected lines, twelve lines from cultivar Kisswany had only 3% infection percentage as compared to 29% in the control, and twelve lines from cultivar Yabroudy had less than 5% infection percentage as compared to 20% in the control. Also, we have been able to improve storability under natural conditions. Weight loss during storage decreased from 8.25% in the control to only 4% in some Kisswany lines and from 10% to 3% in some Yabroudy lines. However, we have not been able to increase the bulb weight over the control but the weights of the selected lines were comparable to those of the control. (author)

GmPGIP3 enhanced resistance to both take-all and common root rot diseases in transgenic wheat.

Science.gov (United States)

Wang, Aiyun; Wei, Xuening; Rong, Wei; Dang, Liang; Du, Li-Pu; Qi, Lin; Xu, Hui-Jun; Shao, Yanjun; Zhang, Zengyan

2015-05-01

Take-all (caused by the fungal pathogen Gaeumannomyces graminis var. tritici, Ggt) and common root rot (caused by Bipolaris sorokiniana) are devastating root diseases of wheat (Triticum aestivum L.). Development of resistant wheat cultivars has been a challenge since no resistant wheat accession is available. GmPGIP3, one member of polygalacturonase-inhibiting protein (PGIP) family in soybean (Glycine max), exhibited inhibition activity against fungal endopolygalacturonases (PGs) in vitro. In this study, the GmPGIP3 transgenic wheat plants were generated and used to assess the effectiveness of GmPGIP3 in protecting wheat from the infection of Ggt and B. sorokiniana. Four independent transgenic lines were identified by genomic PCR, Southern blot, and reverse transcription PCR (RT-PCR). The introduced GmPGIP3 was integrated into the genomes of these transgenic lines and could be expressed. The expressing GmPGIP3 protein in these transgenic wheat lines could inhibit the PGs produced by Ggt and B. sorokiniana. The disease response assessments postinoculation showed that the GmPGIP3-expressing transgenic wheat lines displayed significantly enhanced resistance to both take-all and common root rot diseases caused by the infection of Ggt and B. sorokiniana. These data suggested that GmPGIP3 is an attractive gene resource in improving resistance to both take-all and common root rot diseases in wheat.

Possible application of labelled compounds in plant physiology, biochemistry and protection

International Nuclear Information System (INIS)

Hanker, I.

1981-01-01

Compounds labelled with 14 C, 32 P, 35 S, 54 Mn, 45 Ca, 65 Zn and 86 Rb were used for the study of side effects of insecticides, fungicides, herbicides and other substances used for the treatment of crop plants, of the effects of some plant diseases on biochemical processes in plants, and of the reasons of plant resistance to diseases, i.e., of factors responsible for this resistance. (author)

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.

A critical role for Arabidopsis MILDEW RESISTANCE LOCUS O2 in systemic acquired resistance.

Science.gov (United States)

Gruner, Katrin; Zeier, Tatyana; Aretz, Christina; Zeier, Jürgen

2018-04-16

Members of the MILDEW RESISTANCE LOCUS O (MLO) gene family confer susceptibility to powdery mildews in different plant species, and their existence therefore seems to be disadvantageous for the plant. We recognized that expression of the Arabidopsis MLO2 gene is induced after inoculation with the bacterial pathogen Pseudomonas syringae, promoted by salicylic acid (SA) signaling, and systemically enhanced in the foliage of plants exhibiting systemic acquired resistance (SAR). Importantly, distinct mlo2 mutant lines were unable to systemically increase resistance to bacterial infection after inoculation with P. syringae, indicating that the function of MLO2 is necessary for biologically-induced SAR in Arabidopsis. Our data also suggest that the close homolog MLO6 has a supportive but less critical role in SAR. In contrast to SAR, basal resistance to bacterial infection was not affected in mlo2. Remarkably, SAR-defective mlo2 mutants were still competent in systemically increasing the levels of the SAR-activating metabolites pipecolic acid (Pip) and SA after inoculation, and to enhance SAR-related gene expression in distal plant parts. Furthermore, although MLO2 was not required for SA- or Pip-inducible defense gene expression, it was essential for the proper induction of disease resistance by both SAR signals. We conclude that MLO2 acts as a critical downstream component in the execution of SAR to bacterial infection, being required for the translation of elevated defense responses into disease resistance. Moreover, our data suggest a function for MLO2 in the activation of plant defense priming during a P. syringae challenge. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Transgenerational effects alter plant defence and resistance in nature.

Science.gov (United States)

Colicchio, J

2017-04-01

Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defence. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defence for Mimulus guttatus. After establishing the relationship between trichomes and herbivory, I test for transgenerational effects of wounding on trichome density and herbivore resistance. Patterns of interannual variation in herbivore density and the high cost of plant defence makes plant-herbivore interactions a system in which transgenerational phenotypic plasticity (TPP) is apt to evolve. Here, I demonstrate that parental damage alters offspring trichome density and herbivore resistance in nature. Moreover, this response varies between populations. This is among the first studies to demonstrate that TPP contributes to variation in nature, and also suggests that selection can modify TPP in response to local conditions. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Antimicrobial Activity of Some Medicinal Plant Extracts against Multidrug Resistant Bacteria

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Majid Masoumian

2017-11-01

Full Text Available Background: Nowadays, it is necessary to discover new and efficient antifungal or antimicrobial drugs because of increasing drug resistance organisms. Using medicinal plants for natural treatment of diseases caused by bacterial origin has mainly been considered. Objectives: In this study, the impacts of antimicrobial medicinal plants extract were compared based on four bacteria in vitro. Methods: In this experimental study, disc diffusion assay and the minimum inhibitory concentration (MIC method were used to investigate the antibacterial effects of selected plant extract elicited by two different solvent on S. aureus, E. coli, P. aeruginosa and S. enteric. Data were analyzed with a statistical software program (SPSS 16. Results: The hydro-alcoholic extract of Myrtus communis (myrtle and water extract of Cinnamomun zeylanicum (cinnamon were the most active extracts screened for antimicrobial activities against different four bacteria as tested organisms. The diameter of inhibition zones ranged from 23 to 28 mm. Comparison of the antibacterial effect of plant extracts and commercial drug revealed that the size of inhibition zone of penicillin against Staphylococcus aureus bacterium was larger than the plant extracts. However, myrtle extract at the minimum inhibitory concentration (MIC of 30 mg/mL showed more powerful antibacterial activity compared to the other extracts and even penicillin. Petroselinum crispum (parsley, Nerium oleander (Oleander and Glycyrihiza glabra (licorice were found to have the least effect on the tested bacteria. Conclusions: In the present study, plant extracts with different compounds showed antibacterial activity (especially myrtle and cinnamon. Hence, they can be used as new source for antibacterial substances.

Enhanced Methanol Production in Plants Provides Broad Spectrum Insect Resistance

Science.gov (United States)

Dixit, Sameer; Upadhyay, Santosh Kumar; Singh, Harpal; Sidhu, Om Prakash; Verma, Praveen Chandra; K, Chandrashekar

2013-01-01

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. PMID:24223989

Enhanced methanol production in plants provides broad spectrum insect resistance.

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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.

Plant hygiene and resistance breeding as plant protection and cultivation methods in areas where emission levels are high

Energy Technology Data Exchange (ETDEWEB)

Berge, H

1967-01-01

If plants are to be used for human or animal consumption, phyto-hygiene is of great importance wherever there are significant amounts of emissions. Breeding resistant plants for technical use is important in regions where atmospheric influences such as gas, steam and dust are encountered. Besides the climatic, orographic, edaphic and chronologic conditions, biologic, chemic and physico-mechanic factors influence the incompatible conceptions of phyto-hygiene and resistance breeding. Several examples are quoted.

In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

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Romana Chovanová

2013-01-01

Full Text Available The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis.

Induced mutations for disease resistance in wheat

International Nuclear Information System (INIS)

Cerny, J.; Hanis, M.; Hanisova, A.; Knytl, V.; Sasek, A.

1983-01-01

Mutation induction has been used over a period of 20 years to obtain mutants of wheat with improved disease resistance. 34 wheat cultivars have been treated with X-rays, gamma rays, thermal neutrons or EMS. A great number of mutants were selected. Their mutational origin was verified by electrophoretic analysis of gliadin spectra. Resistances have been confirmed over several generations. None of the mutants have been released yet for commercial cultivation because of shortcomings in yield or susceptibility to other diseases. The use of mutants in cross-breeding is considered. (author)

Towards allele mining of bacterial wilt disease resistance gene in tomato

International Nuclear Information System (INIS)

Galvez, H.F.; Narciso, J.O.; Opina, N.L.; Canama, A.O.; Colle, M.G.; Latiza, M.A.; Caspillo, C.L.; Bituin, J.L.; Frankie, R.B.; Hautea, D.M.

2005-01-01

Tomato (Lycopersicon esculentum Mill.) is the most important vegetable commodity of the Philippines. Bacterial wilt caused by Ralstonia solanacearum is one serious constraint in tomato production particularly during off-season planting. A major locus derived from H7996 that confers resistance to bacterial wilt has been mapped in the tomato genome. To validate the biological function of the resistance locus and generate multiple allele -mimics-, targeted mutation was induced in tomato using gamma ray and ethyl methane sulfonate (EMS) mutagens. Suitable mutagen treatment was established by evaluating a wide range of mutagen doses/concentrations for a) percent seed germination, b) reduction in plant height, and c) loss of resistance. Six hundred Gy and 1.0% EMS were identified to generate large M1 families of H7996. From 10,000 initial seeds treated with either gamma ray or EMS, a total of 3,663 M1 plants were generated. M2 seeds were harvested from all surviving M1 plants. Several DNA markers have been resourced and are being developed specific to the bacterial wilt resistant gene. In the large M2 population, of H7996, both the phenotypic manifestation of bacterial wilt susceptibility and nucleotide changes in the resistance locus will be evaluated. Large M3 families for the different allele series of the bacterial wilt resistance gene will be established for future high throughput TILLING (Targeting Induced Local Lesions in Genomes) analysis in the gene region

A novel gene of Kalanchoe daigremontiana confers plant drought resistance.

Science.gov (United States)

Wang, Li; Zhu, Chen; Jin, Lin; Xiao, Aihua; Duan, Jie; Ma, Luyi

2018-02-07

Kalanchoe (K.) daigremontiana is important for studying asexual reproduction under different environmental conditions. Here, we describe a novel KdNOVEL41 (KdN41) gene that may confer drought resistance and could thereby affect K. daigremontiana development. The detected subcellular localization of a KdN41/Yellow Fluorescent Protein (YFP) fusion protein was in the nucleus and cell membrane. Drought, salt, and heat stress treatment in tobacco plants containing the KdN41 gene promoter driving β-glucuronidase (GUS) gene transcription revealed that only drought stress triggered strong GUS staining in the vascular tissues. Overexpression (OE) of the KdN41 gene conferred improved drought resistance in tobacco plants compared to wild-type and transformed with empty vector plants by inducing higher antioxidant enzyme activities, decreasing cell membrane damage, increasing abscisic acid (ABA) content, causing reinforced drought resistance related gene expression profiles. The 3,3'-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining results also showed less relative oxygen species (ROS) content in KdN41-overexpressing tobacco leaf during drought stress. Surprisingly, by re-watering after drought stress, KdN41-overexpressing tobacco showed earlier flowering. Overall, the KdN41 gene plays roles in ROS scavenging and osmotic damage reduction to improve tobacco drought resistance, which may increase our understanding of the molecular network involved in developmental manipulation under drought stress in K. daigremontiana.

Signal perception, transduction, and response in gravity resistance. Another graviresponse in plants

Science.gov (United States)

Hoson, T.; Saito, Y.; Soga, K.; Wakabayashi, K.

Resistance to the gravitational force is a serious problem that plants have had to solve to survive on land. Mechanical resistance to the pull of gravity is thus a principal graviresponse in plants, comparable to gravitropism. Nevertheless, only limited information has been obtained for this gravity response. We have examined the mechanism of gravity-induced mechanical resistance using hypergravity conditions produced by centrifugation. As a result, we have clarified the outline of the sequence of events leading to the development of mechanical resistance. The gravity signal may be perceived by mechanoreceptors (mechanosensitive ion channels) on the plasma membrane and it appears that amyloplast sedimentation in statocytes is not involved. Transformation and transduction of the perceived signal may be mediated by the structural or physiological continuum of microtubule-cell membrane-cell wall. As the final step in the development of mechanical resistance, plants construct a tough body by increasing cell wall rigidity. The increase in cell wall rigidity is brought about by modification of the metabolism of certain wall constituents and modification of the cell wall environment, especially pH. We need to clarify the details of each step by future space and ground-based experiments.

Transcriptional plant responses critical for resistance towards necrotrophic pathogens

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Rainer P. Birkenbihl

2011-11-01

Full Text Available Plant defenses aimed at necrotrophic pathogens appear to be genetically complex. Despite the apparent lack of a specific recognition of such necrotrophs by products of major R genes, biochemical, molecular, and genetic studies, in particular using the model plant Arabidopsis, have uncovered numerous host components critical for the outcome of such interactions. Although the JA signaling pathway plays a central role in plant defense towards necrotrophs additional signaling pathways contribute to the plant response network. Transcriptional reprogramming is a vital part of the host defense machinery and several key regulators have recently been identified. Some of these transcription factors positively affect plant resistance whereas others play a role in enhancing host susceptibility towards these phytopathogens.

Riboflavin-Induced Disease Resistance Requires the Mitogen-Activated Protein Kinases 3 and 6 in Arabidopsis thaliana.

Science.gov (United States)

Nie, Shengjun; Xu, Huilian

2016-01-01

As a resistance elicitor, riboflavin (vitamin B2) protects plants against a wide range of pathogens. At molecular biological levels, it is important to elucidate the signaling pathways underlying the disease resistance induced by riboflavin. Here, riboflavin was tested to induce resistance against virulent Pseudomonas syringae pv. Tomato DC3000 (Pst DC3000) in Arabidopsis. Results showed that riboflavin induced disease resistance based on MAPK-dependent priming for the expression of PR1 gene. Riboflavin induced transient expression of PR1 gene. However, following Pst DC3000 inoculation, riboflavin potentiated stronger PR1 gene transcription. Further was suggested that the transcript levels of mitogen-activated protein kinases, MPK3 and MPK6, were primed under riboflavin. Upon infection by Pst DC3000, these two enzymes were more strongly activated. The elevated activation of both MPK3 and MPK6 was responsible for enhanced defense gene expression and resistance after riboflavin treatment. Moreover, riboflavin significantly reduced the transcript levels of MPK3 and MPK6 by application of AsA and BAPTA, an H2O2 scavenger and a calcium (Ca2+) scavenger, respectively. In conclusion, MPK3 and MPK6 were responsible for riboflavin-induced resistance, and played an important role in H2O2- and Ca2+-related signaling pathways, and this study could provide a new insight into the mechanistic study of riboflavin-induced defense responses.

More nutritious bananas resist disease | IDRC - International ...

International Development Research Centre (IDRC) Digital Library (Canada)

2010-10-28

Oct 28, 2010 ... English · Français ... By inserting resistant varieties (like FHIA-17 and FHIA-23) between traditional, susceptible plants, we 'trap' ... This has a direct impact on food security by restoring the productivity of the traditional varieties.

Gravity resistance, another graviresponse in plants - role of microtubule-membrane-cell wall continuum

Science.gov (United States)

Hoson, T.; Saito, Y.; Usui, S.; Soga, K.; Wakabayashi, K.

Resistance to the gravitational force has been a serious problem for plants to survive on land, after they first went ashore more than 400 million years ago. Thus, gravity resistance is the principal graviresponse in plants comparable to gravitropism. Nevertheless, only limited information has been obtained for this second gravity response. We have examined the mechanism of gravity resistance using hypergravity conditions produced by centrifugation. The results led a hypothesis on the mechanism of plant resistance to the gravitational force that the plant constructs a tough body by increasing the cell wall rigidity, which are brought about by modification of the cell wall metabolism and cell wall environment, especially pH. The hypothesis was further supported by space experiments during the Space Shuttle STS-95 mission. On the other hand, we have shown that gravity signal may be perceived by mechanoreceptors (mechanosensitive ion channels) on the plasma membrane and amyloplast sedimentation in statocytes is not involved in gravity resistance. Moreover, hypergravity treatment increased the expression levels of genes encoding alpha-tubulin, a component of microtubules and 3-hydroxy-3-methylglutaryl-Coenzyme A reductase (HMGR), which catalyzes a reaction producing mevalonic acid, a key precursor of terpenoids such as membrane sterols. The expression of HMGR and alpha- and beta-tubulin genes increased within several hours after hypergravity treatment, depending on the magnitude of gravity. The determination of levels of gene products as well as the analysis with knockout mutants of these genes by T-DNA insertions in Arabidopsis supports the involvement of both membrane sterols and microtubules in gravity resistance. These results suggest that structural or physiological continuum of microtubule-cell membrane-cell wall is responsible for plant resistance to the gravitational force.

Summer freezing resistance: a critical filter for plant community assemblies in Mediterranean high mountains

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David Sánchez Pescador

2016-02-01

Full Text Available Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain by measuring their ice nucleation temperature, freezing point (FP, and low-temperature damage (LT50, as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance. The community response to freezing was estimated for each plot as community weighted means (CWMs and functional diversity, and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content, and seed mass. There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the functional diversity of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only the leaf dry matter content correlated negatively with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower functional diversity of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to

Induction of Systemic Resistance against Insect Herbivores in Plants by Beneficial Soil Microbes

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Md. Harun-Or Rashid

2017-10-01

Full Text Available Soil microorganisms with growth-promoting activities in plants, including rhizobacteria and rhizofungi, can improve plant health in a variety of different ways. These beneficial microbes may confer broad-spectrum resistance to insect herbivores. Here, we provide evidence that beneficial microbes modulate plant defenses against insect herbivores. Beneficial soil microorganisms can regulate hormone signaling including the jasmonic acid, ethylene and salicylic acid pathways, thereby leading to gene expression, biosynthesis of secondary metabolites, plant defensive proteins and different enzymes and volatile compounds, that may induce defenses against leaf-chewing as well as phloem-feeding insects. In this review, we discuss how beneficial microbes trigger induced systemic resistance against insects by promoting plant growth and highlight changes in plant molecular mechanisms and biochemical profiles.

Exogenous melatonin improves Malus resistance to Marssonina apple blotch.

Science.gov (United States)

Yin, Lihua; Wang, Ping; Li, Mingjun; Ke, Xiwang; Li, Cuiying; Liang, Dong; Wu, Shan; Ma, Xinli; Li, Chao; Zou, Yangjun; Ma, Fengwang

2013-05-01

We examined whether exogenously applied melatonin could improve resistance to Marssonina apple blotch (Diplocarpon mali) by apple [Malus prunifolia (Willd.) Borkh. cv. Donghongguo]. This serious disease leads to premature defoliation in the main regions of apple production. When plants were pretreated with melatonin, resistance was increased in the leaves. We investigated the potential roles for melatonin in modulating levels of hydrogen peroxide (H2O2), as well the activities of antioxidant enzymes and pathogenesis-related proteins during these plant-pathogen interactions. Pretreatment enabled plants to maintain intracellular H2O2 concentrations at steady-state levels and enhance the activities of plant defence-related enzymes, possibly improving disease resistance. Because melatonin is safe and beneficial to animals and humans, exogenous pretreatment might represent a promising cultivation strategy to protect plants against this pathogen infection. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Induced multiple disease resistance in wheat

International Nuclear Information System (INIS)

Borojevic, K.; Worland, A.J.

1990-01-01

Full text: The existence of genes suppressing resistance to leaf rust, stem rust and yellow rust in hexaploid wheat has been suggested. If such genes are deleted or inactivated, a more resistant variety may be obtained. In mutant lines of the wheat variety San Pastore, selected after treatment with 20,000 rad of gamma-rays, resistance to leaf rust, yellow rust, stem rust, and to some extent to Erysiphe graminis was determined. The mutants responded to infection by producing necrotic flecks in the presence of high level of disease inoculum. Similar flecks develop under stress condition. It is likely that the mother variety San Pastore carries genes for resistance which are masked by suppressor genes. Irradiation inactivates suppressors so that resistance genes which were previously masked are expressed. The first results of monosomic analysis indicate that chromosomes of groups 4 and 5 or possibly 7 may be critical for expression of resistance in the mutant lines. (author)

Transgenic wheat expressing Thinopyrum intermedium MYB transcription factor TiMYB2R-1 shows enhanced resistance to the take-all disease.

Science.gov (United States)

Liu, Xin; Yang, Lihua; Zhou, Xianyao; Zhou, Miaoping; Lu, Yan; Ma, Lingjian; Ma, Hongxiang; Zhang, Zengyan

2013-05-01

The disease take-all, caused by the fungus Gaeumannomyces graminis, is one of the most destructive root diseases of wheat worldwide. Breeding resistant cultivars is an effective way to protect wheat from take-all. However, little progress has been made in improving the disease resistance level in commercial wheat cultivars. MYB transcription factors play important roles in plant responses to environmental stresses. In this study, an R2R3-MYB gene in Thinopyrum intermedium, TiMYB2R-1, was cloned and characterized. The gene sequence includes two exons and an intron. The expression of TiMYB2R-1 was significantly induced following G. graminis infection. An in vitro DNA binding assay proved that TiMYB2R-1 protein could bind to the MYB-binding site cis-element ACI. Subcellular localization assays revealed that TiMYB2R-1 was localized in the nucleus. TiMYB2R-1 transgenic wheat plants were generated, characterized molecularly, and evaluated for take-all resistance. PCR and Southern blot analyses confirmed that TiMYB2R-1 was integrated into the genomes of three independent transgenic wheat lines by distinct patterns and the transgene was heritable. Reverse transcription-PCR and western blot analyses revealed that TiMYB2R-1 was highly expressed in the transgenic wheat lines. Based on disease response assessments for three successive generations, the significantly enhanced resistance to take-all was observed in the three TiMYB2R-1-overexpressing transgenic wheat lines. Furthermore, the transcript levels of at least six wheat defence-related genes were significantly elevated in the TiMYB2R-1 transgenic wheat lines. These results suggest that engineering and overexpression of TiMYB2R-1 may be used for improving take-all resistance of wheat and other cereal crops.

Antibacterial activity of combined medicinal plants extract against multiple drug resistant strains

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Rafiqul Islam

2015-06-01

Full Text Available Objective: To find out the combined antibacterial efficacy of Aegle marmelos, Aphanamixis polystachya, Cuscuta reflexa and Aesclynomene indica against bacterial pathogens. Methods: Antibacterial potency of combined plant extracts has been tested against Bacillus subtilis IFO 3026, Sarcina lutea IFO 3232, Xanthomonas campestris IAM 1671, Escherichia coli IFO 3007, Klebsiella pneumoniae ATTC 10031, Proteus vulgaris MTCC 321 and Pseudomonas denitrificans KACC 32026 by disc diffusion assay. Commercially available standard antibiotic discs were also used to find out antibiotic resistance pattern of test organisms. Results: Among the test organisms, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae and Proteus denitrificans showed resistance against multiple commercially available antibiotics. On the other hand, these multiple drug resistant organisms showed susceptibility against combined plant extracts. Conclusions: These combined plants extracts showed synergistic antibacterial activity and could lead to new antibacterial drug designing.

Bleomycin resistance : a new dominant selectable marker for plant cell transformation

NARCIS (Netherlands)

Hille, Jacques; Verheggen, Frank; Roelvink, Peter; Franssen, Henk; Kammen, Ab van; Zabel, Pim

1986-01-01

Plant cells are sensitive to the antibiotic bleomycin, a DNA damaging glycopeptide. A bleomycin resistance determinant, located on transposon Tn5 and functional in bacteria, has been cloned in a plant expression vector and introduced into Nicotiana plumbaginifolia using Agrobacterium tumefaciens.

Physiological plant investigations for the purpose of growing smoke resistant conifers

Energy Technology Data Exchange (ETDEWEB)

Polster, H; Bortitz, S; Vogl, M

1965-01-01

Spruce and pine are the main commercial wood varieties used in East Germany. These are also the most sensitive to smoke. Usually replacement of the damaged trees is necessary. The Department of Smoke Research of the Institute for Plant Chemistry of the Dresden Institute of Technology has been able to develop conifers resistant to SO2. In order to select smoke resistant trees for breeding, the Institute for Forestry and Plant Physiology of the Institute of Forestry Breeding in Graupa, East Germany has developed a rapid selection test. It is based on subjecting a small branch to doses of SO2. A method of breeding smoke resistant conifers is given in detail. It takes approximately ten years to produce the seeds.

When a Plant Resistance Inducer Leaves the Lab for the Field: Integrating ASM into Routine Apple Protection Practices.

Science.gov (United States)

Marolleau, Brice; Gaucher, Matthieu; Heintz, Christelle; Degrave, Alexandre; Warneys, Romain; Orain, Gilles; Lemarquand, Arnaud; Brisset, Marie-Noëlle

2017-01-01

Plant resistance inducers, also called elicitors, could be useful to reduce the use of pesticides. However, their performance in controlling diseases in the field remains unsatisfactory due to lack of specific knowledge of how they can integrate crop protection practices. In this work, we focused on apple crop and acibenzolar- S -methyl (ASM), a well-known SAR (systemic acquired resistance) inducer of numerous plant species. We provide a protocol for orchard-effective control of apple scab due to the ascomycete fungus Venturia inaequalis , by applying ASM in combination with a light integrated pest management program. Besides we pave the way for future optimization levers by demonstrating in controlled conditions (i) the high influence of apple genotypes, (ii) the ability of ASM to prime defenses in newly formed leaves, (iii) the positive effect of repeated elicitor applications, (iv) the additive effect of a thinning fruit agent.

Possible application of labelled compounds in plant physiology, biochemistry and protection

Energy Technology Data Exchange (ETDEWEB)

Hanker, I. (Vyzkumne Ustavy Rostlinne Vyroby, Prague (Czechoslovakia). Ustav Ochrany Rostlin)

1981-06-01

Compounds labelled with /sup 14/C, /sup 32/P, /sup 35/S, /sup 54/Mn, /sup 45/Ca, /sup 65/Zn and /sup 86/Rb were used for the study of side effects of insecticides, fungicides, herbicides and other substances used for the treatment of crop plants, of the effects of some plant diseases on biochemical processes in plants, and of the reasons of plant resistance to diseases, i.e., of factors responsible for this resistance.

Identification of genes involved in rhizobacteria-mediated induced systemic resistance in Arabidopsis

NARCIS (Netherlands)

Léon-Kloosterziel, K.M.; Verhagen, B.W.M.; Keurentjes, J.J.B.; Loon, L.C. van; Pieterse, C.M.J.

2002-01-01

Different forms of biologically induced disease resistance have been identified in plants. Following attack by a necrotizing pathogen systemic acquired resistance (SAR) is induced, leading to a broad-spectrum disease resistance that is associated with an increase in salicylic acid (SA) levels

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.

Protein modeling of yellow rust disease in wheat

International Nuclear Information System (INIS)

Aziz, S.E.; Bano, R.; Zayed, M.E.; Elshikh, M.S.; Khan, M.H.; Chaudhry, Z.

2017-01-01

Wheat production in Pakistan is affected by yellow rust disease caused by a fungus Puccinia striiformis. There is a need to broaden the genetic basis of wheat by identifying new resistance genes. The present study was aimed to identify an alternate resistance gene for yellow rust disease in wheat caused by Puccinia striiformis. Genome sequence was compared with databases and similar gene was identified for disease resistance in rye plant. Structural analysis of RGA1 gene (resistance gene in wheat) was carried out using different bioinformatics tools and an alternative gene having same structure was identified on the basis of structural and sequence homology. Rye plant is the proposed plant for the alternate new resistance gene. The result of pairwise alignment of RGA1 gene in wheat and gene of rye plant is 94.2% with accession DQ494535 .The secondary structures of both the genes was compared and found similar to each other. These comparisons between the wheat resistance gene and gene from rye plant depict structural similarities between the two genes. Results of RGA1 gene's structural analysis in wheat is as follow: Helices: 59, Extended sheets: 30, Turns: 12, Coils: 13 and for alternate resistance genes in Rye is as follow: Helices: 52, Extended sheets: 30, Turns: 14, Coils: 17. As structures are similar, the alternate identified gene could be used for resistance in wheat. (author)

iPathology: Robotic Applications and Management of Plants and Plant Diseases

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Yiannis Ampatzidis

2017-06-01

Full Text Available The rapid development of new technologies and the changing landscape of the online world (e.g., Internet of Things (IoT, Internet of All, cloud-based solutions provide a unique opportunity for developing automated and robotic systems for urban farming, agriculture, and forestry. Technological advances in machine vision, global positioning systems, laser technologies, actuators, and mechatronics have enabled the development and implementation of robotic systems and intelligent technologies for precision agriculture. Herein, we present and review robotic applications on plant pathology and management, and emerging agricultural technologies for intra-urban agriculture. Greenhouse advanced management systems and technologies have been greatly developed in the last years, integrating IoT and WSN (Wireless Sensor Network. Machine learning, machine vision, and AI (Artificial Intelligence have been utilized and applied in agriculture for automated and robotic farming. Intelligence technologies, using machine vision/learning, have been developed not only for planting, irrigation, weeding (to some extent, pruning, and harvesting, but also for plant disease detection and identification. However, plant disease detection still represents an intriguing challenge, for both abiotic and biotic stress. Many recognition methods and technologies for identifying plant disease symptoms have been successfully developed; still, the majority of them require a controlled environment for data acquisition to avoid false positives. Machine learning methods (e.g., deep and transfer learning present promising results for improving image processing and plant symptom identification. Nevertheless, diagnostic specificity is a challenge for microorganism control and should drive the development of mechatronics and robotic solutions for disease management.

Endogenous small RNAs and antibacterial immunity in plants.

Science.gov (United States)

Jin, Hailing

2008-08-06

Small RNAs are non-coding regulatory RNA molecules that control gene expression by mediating mRNA degradation, translational inhibition, or chromatin modification. Virus-derived small RNAs induce silencing of viral RNAs and are essential for antiviral defense in both animal and plant systems. The role of host endogenous small RNAs on antibacterial immunity has only recently been recognized. Host disease resistance and defense responses are achieved by activation and repression of a large array of genes. Certain endogenous small RNAs in plants, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are induced or repressed in response to pathogen attack and subsequently regulate the expression of genes involved in disease resistance and defense responses by mediating transcriptional or post-transcriptional gene silencing. Thus, these small RNAs play an important role in gene expression reprogramming in plant disease resistance and defense responses. This review focuses on the recent findings of plant endogenous small RNAs in antibacterial immunity.

A retrospective of an unconventionally trained plant pathologist: plant diseases to molecular plant pathology.

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Ouchi, Seiji

2006-01-01

Plant pathology evolved from its mycology-oriented origins into a science dealing with biochemical mechanisms of diseases, along with enhanced crop production through disease control. This retrospective describes first my personal experience from my introduction to plant pathology, to the establishment of the concept of accessibility as a model pertaining to genetically defined basic compatibility induced by pathogens. I then refer to the development of molecular plant pathology from physiological and biochemical plant pathology fostered by the growth in recombinant technology in the second half of the past century. This progress was best reflected by the U.S.-Japan Seminar Series held at 4-5-year intervals from 1966 to 2003 and documented by publications in major journals of our discipline. These seminars emphasized that progress in science has always been supported by the invention of novel techniques and that knowledge integrated from modern genomics and subsequent proteomics should contribute to the progress of basic life sciences and, more importantly, to the elaboration of rational measures for disease control.

A fungal root symbiont modifies plant resistance to an insect herbivore.

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Borowicz, Victoria A

1997-11-01

Vesicular-arbuscular mycorrhizal (VAM) fungi are common root-colonizing symbionts that affect nutrient uptake by plants and can alter plant susceptibility to herbivores. I conducted a factorial experiment to test the hypotheses that colonization by VAM fungi (1) improves soybean (Glycine max) tolerance to grazing by folivorous Mexican bean beetle (Epilachna varivestis), and (2) indirectly affects herbivores by increasing host resistance. Soybean seedlings were inoculated with the VAM fungus Glomus etunicatum or VAM-free filtrate and fertilized with high-[P] or low-[P] fertilizer. After plants had grown for 7 weeks first-instar beetle larvae were placed on bagged leaves. Growth of soybean was little affected by grazing larvae, and no effects of treatments on tolerance of soybeans to herbivores were evident. Colonization by VAM fungus doubled the size of phosphorus-stressed plants but these plants were still half the size of plants given adequate phosphorus. High-[P] fertilizer increased levels of phosphorus and soluble carbohydrates, and decreased levels of soluble proteins in leaves of grazed plants. Colonization of grazed plants by VAM fungus had no significant effect on plant soluble carbohydrates, but increased concentration of phosphorus and decreased levels of proteins in phosphorus-stressed plants to concentrations similar to those of plants given adequate phosphorus. Mexican bean beetle mass at pupation, pupation rate, and survival to eclosion were greatest for beetles reared on phosphorus-stressed, VAM-colonized plants, refuting the hypothesis that VAM colonization improves host plant resistance. VAM colonization indirectly affected performance of Mexician bean beetle larvae by improving growth and nutrition of the host plant.

Comparison of ALS functionality and plant growth in ALS-inhibitor susceptible and resistant Myosoton aquaticum L.

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Liu, Weitang; Bai, Shuang; Jia, Sisi; Guo, Wenlei; Zhang, Lele; Li, Wei; Wang, Jinxin

2017-10-01

Herbicide target-site resistance mutations may cause pleiotropic effects on plant ecology and physiology. The effect of several known (Pro197Ser, Pro197Leu Pro197Ala, and Pro197Glu) target-site resistance mutations of the ALS gene on both ALS functionality and plant vegetative growth of weed Myosoton aquaticum L. (water chickweed) have been investigated here. The enzyme kinetics of ALS from four purified water chickweed populations that each homozygous for the specific target-site resistance-endowing mutations were characterized and the effect of these mutations on plant growth was assessed via relative growth rate (RGR) analysis. Plants homozygous for Pro197Ser and Pro197Leu exhibited higher extractable ALS activity than susceptible (S) plants, while all ALS mutations with no negative change in ALS kinetics. The Pro197Leu mutation increased ALS sensitivity to isoleucine and valine, and Pro197Glu mutation slightly increased ALS sensitivity to isoleucine. RGR results indicated that none of these ALS resistance mutations impose negative pleiotropic effects on relative growth rate. However, resistant (R) seeds had a lowed germination rate than S seeds. This study provides baseline information on ALS functionality and plant growth characteristics associated with ALS inhibitor resistance-endowing mutations in water chickweed. Copyright © 2017. Published by Elsevier Inc.

Analysis of the grape (Vitis vinifera L.) thaumatin-like protein (TLP) gene family and demonstration that TLP29 contributes to disease resistance.

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Yan, Xiaoxiao; Qiao, Hengbo; Zhang, Xiuming; Guo, Chunlei; Wang, Mengnan; Wang, Yuejin; Wang, Xiping

2017-06-27

Thaumatin-like protein (TLP) is present as a large family in plants, and individual members play different roles in various responses to biotic and abiotic stresses. Here we studied the role of 33 putative grape (Vitis vinifera L.) TLP genes (VvTLP) in grape disease resistance. Heat maps analysis compared the expression profiles of 33 genes in disease resistant and susceptible grape species infected with anthracnose (Elsinoe ampelina), powdery mildew (Erysiphe necator) or Botrytis cinerea. Among these 33 genes, the expression level of TLP29 increased following the three pathogens inoculations, and its homolog from the disease resistant Chinese wild grape V. quinquangularis cv. 'Shang-24', was focused for functional studies. Over-expression of TLP29 from grape 'Shang-24' (VqTLP29) in Arabidopsis thaliana enhanced its resistance to powdery mildew and the bacterium Pseudomonas syringae pv. tomato DC3000, but decreased resistance to B. cinerea. Moreover, the stomatal closure immunity response to pathogen associated molecular patterns was strengthened in the transgenic lines. A comparison of the expression profiles of various resistance-related genes after infection with different pathogens indicated that VqTLP29 may be involved in the salicylic acid and jasmonic acid/ethylene signaling pathways.

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

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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.

RNAi technology extends its reach: Engineering plant resistance ...

African Journals Online (AJOL)

RNA interference (RNAi) is a homology-dependent gene silencing technology that is initiated by double stranded RNA (dsRNA). It has emerged as a genetic tool for engineering plants resistance against prokaryotic pathogens such as virus and bacteria. Recent studies broaden the role of RNAi, and many successful ...

Recognizing Plant Defense Priming.

Science.gov (United States)

Martinez-Medina, Ainhoa; Flors, Victor; Heil, Martin; Mauch-Mani, Brigitte; Pieterse, Corné M J; Pozo, Maria J; Ton, Jurriaan; van Dam, Nicole M; Conrath, Uwe

2016-10-01

Defense priming conditions diverse plant species for the superinduction of defense, often resulting in enhanced pest and disease resistance and abiotic stress tolerance. Here, we propose a guideline that might assist the plant research community in a consistent assessment of defense priming in plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

A maize resistance gene functions against bacterial streak disease in rice

OpenAIRE

Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

2005-01-01

Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, wh...

Plant community resistance to invasion by Bromus species – the roles of community attributes, Bromus Interactions with plant communities, and Bromus traits

Science.gov (United States)

Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B

2016-01-01

The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.

Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

Energy Technology Data Exchange (ETDEWEB)

Somerville, Chris R.; Scieble, Wolf

2000-10-11

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.

[Effects and mechanisms of plant roots on slope reinforcement and soil erosion resistance: a research review].

Science.gov (United States)

Xiong, Yan-Mei; Xia, Han-Ping; Li, Zhi-An; Cai, Xi-An

2007-04-01

Plant roots play an important role in resisting the shallow landslip and topsoil erosion of slopes by raising soil shear strength. Among the models in interpreting the mechanisms of slope reinforcement by plant roots, Wu-Waldron model is a widely accepted one. In this model, the reinforced soil strength by plant roots is positively proportional to average root tensile strength and root area ratio, the two most important factors in evaluating slope reinforcement effect of plant roots. It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them. The increase of soil erosion resistance by plant roots was mainly through the actions of fiber roots less than 1 mm in diameter, while fiber roots enhanced the soil stability to resist water dispersion via increasing the number and diameter of soil water-stable aggregates. Fine roots could also improve soil permeability effectively to decrease runoff and weaken soil erosion.

Effects of plant morphology on vegetation resistance, resilience and ...

African Journals Online (AJOL)

Effects of plant morphology on vegetation resistance, resilience and tolerance in. Mabira forest ... impacts of visitors activities of the camping sites and to understand the .... (Howard, 199 1 ): Milicia excels a, Cordia millenii, Irving/a gabonensis ...

Selection of mutants resistant to black spot disease by chronic irradiation of gamma-rays in Japanese pear 'Osanijisseiki'

International Nuclear Information System (INIS)

Masuda, Tetsuo; Yoshioka, Toji; Kotobuki, Kazuo; Sanada, Tetsuro; Inoue, Kosuke; Murata, Kenji; Kitagawa, Kenichi; Tabira, Hiroki; Yoshida, Akira

1997-01-01

'Osanijisseiki', a self-compatible, spontaneous bud sport of the Japanese pear 'Nijisseiki' is an excellent cultivar with a smooth skin. However, this cultivar is susceptible to Japanese pear black spot disease caused by Alternaria alternata Japanese pear pathotype. To obtain resistant mutants from 'Osanijisseiki', nursery plants of 'Osanijisseiki' have been irradiated chronically with gamma-rays in the Gamma Field of the Institute of Radiation Breeding, NAR, MAFF, since 1986. Screening tests using AK toxin, a host-specific toxin produced by A. alternata Japanese pear pathotype, were performed form 1988 to 1993. Four branches of young trees planted at a distance of 40 m from the 60 Co source were selected as being resistant mutants in 1991 (IRB 502-13T and IRB 502-14T) and 1993 (IRB 502-17T and IRB 502-18T). Sensitivity of the four resistant mutants to AK-toxin and susceptibility to the pathogen were compared with other of susceptible and resistant cultivars. The results showed that these four mutants possessed intermediate resistance. Furthermore, a mutant, IRB 502-13T, had the same characteristics as the original 'Osanijisseiki', except for the difference in toxin sensitivity. The characteristics of the other mutants, IRB 502 14-T, IRB 502-17T, and IRB 502-18T, care being examined. (author)

within plant resistance to water flow in tomato and sweet melons

African Journals Online (AJOL)

Administrator

high pressure flow meter (HPFM) and evaporative flux (EF) methods. In the evaporative flux method, measure- ments of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using. Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated ...

Recognizing Plant Defense Priming

NARCIS (Netherlands)

Martinez-Medina, Ainhoa; Flors, Victor; Heil, Martin; Mauch-Mani, Brigitte; Pieterse, Corné M J|info:eu-repo/dai/nl/113115113; Pozo, Maria J; Ton, Jurriaan; van Dam, Nicole M; Conrath, Uwe

2016-01-01

Defense priming conditions diverse plant species for the superinduction of defense, often resulting in enhanced pest and disease resistance and abiotic stress tolerance. Here, we propose a guideline that might assist the plant research community in a consistent assessment of defense priming in

Recognizing plant defense priming

NARCIS (Netherlands)

Martinez-Medina, A.; Flors, V.; Heil, M.; Mauch-Mani, B.; Pieterse, C.M.J.; Pozo, M.J.; Ton, J.; Van Dam, N.M.; Conrath, U.

2016-01-01

Defense priming conditions diverse plant species for the superinduction of defense, often resulting in enhanced pest and disease resistance and abiotic stress tolerance. Here, we propose a guideline that might assist the plant research community in a consistent assessment of defense priming in

Transgenic Citrus Expressing an Arabidopsis NPR1 Gene Exhibit Enhanced Resistance against Huanglongbing (HLB; Citrus Greening).

Science.gov (United States)

Dutt, Manjul; Barthe, Gary; Irey, Michael; Grosser, Jude

2015-01-01

Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB), a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars 'Hamlin' and 'Valencia' expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSUC2) promoter were produced. Overexpression of AtNPR1 resulted in trees with normal phenotypes that exhibited enhanced resistance to HLB. Phloem specific expression of NPR1 was equally effective for enhancing disease resistance. Transgenic trees exhibited reduced diseased severity and a few lines remained disease-free even after 36 months of planting in a high-disease pressure field site. Expression of the NPR1 gene induced expression of several native genes involved in the plant defense signaling pathways. The AtNPR1 gene being plant derived can serve as a component for the development of an all plant T-DNA derived consumer friendly GM tree.

Transgenic Citrus Expressing an Arabidopsis NPR1 Gene Exhibit Enhanced Resistance against Huanglongbing (HLB; Citrus Greening.

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Manjul Dutt

Full Text Available Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB, a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars 'Hamlin' and 'Valencia' expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSUC2 promoter were produced. Overexpression of AtNPR1 resulted in trees with normal phenotypes that exhibited enhanced resistance to HLB. Phloem specific expression of NPR1 was equally effective for enhancing disease resistance. Transgenic trees exhibited reduced diseased severity and a few lines remained disease-free even after 36 months of planting in a high-disease pressure field site. Expression of the NPR1 gene induced expression of several native genes involved in the plant defense signaling pathways. The AtNPR1 gene being plant derived can serve as a component for the development of an all plant T-DNA derived consumer friendly GM tree.

Proteome Analysis of Disease Resistance against Ralstonia solanacearum in Potato Cultivar CT206-10

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Sangryeol Park

2016-02-01

Full Text Available Potato is one of the most important crops worldwide. Its commercial cultivars are highly susceptible to many fungal and bacterial diseases. Among these, bacterial wilt caused by Ralstonia solanacearum causes significant yield loss. In the present study, integrated proteomics and genomics approaches were used in order to identify bacterial wilt resistant genes from Rs resistance potato cultivar CT-206-10. 2-DE and MALDI-TOF/TOF-MS analysis identified eight differentially abundant proteins including glycine-rich RNA binding protein (GRP, tomato stress induced-1 (TSI-1 protein, pathogenesis-related (STH-2 protein and pentatricopeptide repeat containing (PPR protein in response to Rs infection. Further, semi-quantitative RT-PCR identified up-regulation in transcript levels of all these genes upon Rs infection. Taken together, our results showed the involvement of the identified proteins in the Rs stress tolerance in potato. In the future, it would be interesting to raise the transgenic plants to further validate their involvement in resistance against Rs in potato.

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

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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.

miR482 and Its Isoforms in Plants

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Abdil Hakan EREN

2016-09-01

Full Text Available In plants, miR482 family members are generally 22-nucleotide long, distinguishing from other microRNA (miRNA families by their extraordinary and diverse sequence structures. Studies showed that miRNA482 is related to NBLRR (Nucleotide binding-site leucine-rich repeat genes conferring resistance to disease in plants. There are different coded NB-LRR genes which are considered as the part immune response assisting the recognition of pathogens in plant genomes. NB-LRR proteins are mostly related to effector – triggering immune system against pathogens. The main immune receptors in plants are PRR (Pattern recoginition receptor and R (Resistance proteins. R proteins code for immune system proteins by NB-LRR activity. miR482, miR1448, slmiR2118 and ath-miR472 are disease resistance related miRNAs. In several studies, miR482 was found to be a homolog of miR1448 and phylogenetic analyses showed that miR1448 is formed by tandem duplication of miR482. While suppression of miR482 results in plant susceptibility to pathogens, miR482 was considered to play role in nodulation and mycorrhizal processes of soya roots. Increasing evidences exhibit that miR482 is critical in disease resistance against pathogen attacks.

ANTIBACTERIAL ACTIVITY OF SOME WILD MEDICAL PLANTS EXTRACT TO ANTIBIOTIC RESISTANT ESCHERICHIA COLI

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Lukáš Hleba

2013-02-01

Full Text Available Antibiotics are probably the most successful family of drugs so far developed for improving human health. Because of increasing resistance to antibiotics of many bacteria, plant extracts and plant compounds are of new interest as antiseptics and antimicrobial agents in medicine. In this study, we researched antimicrobial effects of extracts of some medical plants (Tussilagofarfara, Equisetum arvense, Sambucusnigra, Aesculushippocastanumand Taraxacumofficinale from Slovakia to antibiotic resistant and antibiotic sensitive bacteria isolated from milk of cows and mare, which were breeded in different conditions. Microorganisms which were used in this experiment we isolated from milk from conventional breeding of cows (tenE. coli strains and from ecological breeding of Lipicanmare (tenE. coli strains by sterile cotton swabs. For antibiotic susceptibility testing was used disc diffusion method according by EUCAST. After dried at room temperature we weighed 50 g of crushed medical plants (parts and it were to extract in 400 ml methanol for two weeks at room temperature. For antimicrobial susceptibility testing of medical plants extract blank discs with 6 mm diameter disc diffusion method was used. We determined that all Escherichia coli strains isolated from milk of conventional breeding of cows were resistant to ampicillin and chloramphenicol. We determined that all tested ampicillin and chloramphenicol resistant E. coli strains isolated from conventional breeding of cow showed susceptibility to all used medical plants extracts. In difference, we determined that antibiotic susceptible E. coli strains isolated from ecological breeding of Lipicanmare were susceptible to Tussilagofarfara extract only. From these results we could be conclude some observations, which could be important step in treatment of bacterial infections caused by antibiotic resistant bacteria and it could be important knowledge for treatment of livestock in conventional breeding

Bacterial Gibberellins Induce Systemic Resistance of Plants

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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

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

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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.

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.

Within plant resistance to water flow in tomato and sweet melons ...

African Journals Online (AJOL)

In the evaporative flux method, measurements of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated from the slope of their relationship, ranged from 6.57x10-01 to ...

Plant-to-plant communication triggered by systemin primes anti-herbivore resistance in tomato.

Science.gov (United States)

Coppola, Mariangela; Cascone, Pasquale; Madonna, Valentina; Di Lelio, Ilaria; Esposito, Francesco; Avitabile, Concetta; Romanelli, Alessandra; Guerrieri, Emilio; Vitiello, Alessia; Pennacchio, Francesco; Rao, Rosa; Corrado, Giandomenico

2017-11-14

Plants actively respond to herbivory by inducing various defense mechanisms in both damaged (locally) and non-damaged tissues (systemically). In addition, it is currently widely accepted that plant-to-plant communication allows specific neighbors to be warned of likely incoming stress (defense priming). Systemin is a plant peptide hormone promoting the systemic response to herbivory in tomato. This 18-aa peptide is also able to induce the release of bioactive Volatile Organic Compounds, thus also promoting the interaction between the tomato and the third trophic level (e.g. predators and parasitoids of insect pests). In this work, using a combination of gene expression (RNA-Seq and qRT-PCR), behavioral and chemical approaches, we demonstrate that systemin triggers metabolic changes of the plant that are capable of inducing a primed state in neighboring unchallenged plants. At the molecular level, the primed state is mainly associated with an elevated transcription of pattern -recognition receptors, signaling enzymes and transcription factors. Compared to naïve plants, systemin-primed plants were significantly more resistant to herbivorous pests, more attractive to parasitoids and showed an increased response to wounding. Small peptides are nowadays considered fundamental signaling molecules in many plant processes and this work extends the range of downstream effects of this class of molecules to intraspecific plant-to-plant communication.

RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes

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Sagar Banerjee

2017-05-01

Full Text Available Plant parasitic nematodes cause severe damage and yield loss in major crops all over the world. Available control strategies include use of insecticides/nematicides but these have proved detrimental to the environment, while other strategies like crop rotation and resistant cultivars have serious limitations. This scenario provides an opportunity for the utilization of technological advances like RNA interference (RNAi to engineer resistance against these devastating parasites. First demonstrated in the model free living nematode, Caenorhabtidis elegans; the phenomenon of RNAi has been successfully used to suppress essential genes of plant parasitic nematodes involved in parasitism, nematode development and mRNA metabolism. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant parasitic nematodes with significant success. However, host delivered in planta RNAi has proved to be a pioneering phenomenon to deliver dsRNAs to feeding nematodes and silence the target genes to achieve resistance. Highly enriched genomic databases are exploited to limit off target effects and ensure sequence specific silencing. Technological advances like gene stacking and use of nematode inducible and tissue specific promoters can further enhance the utility of RNAi based transgenics against plant parasitic nematodes.

Development of Efficient Screening Methods for Resistant Cucumber Plants to Meloidogyne incognita

Directory of Open Access Journals (Sweden)

Sung Min Hwang

2014-06-01

Full Text Available Root-knot nematodes represent a significant problem in cucumber, causing reduction in yield and quality. To develop screening methods for resistance of cucumber to root-knot nematode Meloidogyne incognita, development of root-knot nematode of four cucumber cultivars (‘Dragonsamchuk’, ‘Asiastrike’, ‘Nebakja’ and ‘Hanelbakdadaki’ according to several conditions such as inoculum concentration, plant growth stage and transplanting period was investigated by the number of galls and egg masses produced in each seedling 45 days after inoculation. There was no difference in galls and egg masses according to the tested condition except for inoculum concentration. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. On the basis of the result, the optimum conditions for root-knot development on the cultivars is to transplant period of 1 week, inoculum concentration of 5,000 eggs/plant and plant growth stage of 3-week-old in a greenhouse (25 ± 5°C. In addition, under optimum conditions, resistance of 45 commercial cucumber cultivars was evaluated. One rootstock cultivar, Union was moderately resistant to the root-knot nematode. However, no significant difference was in the resistance of the others cultivar. According to the result, we suggest an efficient screening method for new resistant cucumber to the root-knot nematode, M. incognita.

Major diseases of ornamental plants and their management

International Nuclear Information System (INIS)

Akhtar, M.A.; Zakria, M.; Sohail, F.

2003-01-01

Major diseases of ornamental plants are caused by infections agents (biotic) or non-infectious (abiotic) agents. Infectious agents are bacteria, fungi, nematodes and virus. Non infectious agents are nutritional imbalances, environmental stresses and chemical toxicities. Grouping of the diseases has been done on symptomatology basis. Disease management in ornamental plants has been described through cultural practices, chemical and other control strategies. (author)

Natural Variation in Elicitation of Defense-Signaling Associates to Field Resistance Against the Spot Blotch Disease in Bread Wheat (Triticum aestivum L.)

OpenAIRE

Sandeep Sharma; Ranabir Sahu; Sudhir Navathe; Vinod K. Mishra; Ramesh Chand; Pawan K. Singh; Arun K. Joshi; Shree P. Pandey

2018-01-01

Spot blotch, caused by the hemibiotropic fungus Bipolaris sorokiniana, is amongst the most damaging diseases of wheat. Still, natural variation in expression of biochemical traits that determine field resistance to spot blotch in wheat remain unaddressed. To understand how genotypic variations relate to metabolite profiles of the components of defense-signaling and the plant performance, as well as to discover novel sources of resistance against spot blotch, we have conducted field studies us...

Management of vascular wilt of lentil through host plant resistance, biological control agents and chemicals

International Nuclear Information System (INIS)

Rafique, K.; Rauf, C.A.; Naz, F.

2016-01-01

The management of devastating lentil (Lens culinaris Medik.) wilt disease was investigated through evaluation of host plant resistance, biological control agents and seed treatment with different fungicides against a known most aggressive isolate i.e. FWL12 (KP297995) of Fusarium oxysporum f. sp. lentis. The In vitro screening of germplasm (23 advanced lines and cultivars) for host resistance by root dip method revealed five cultivars viz. Markaz-09, Masoor-86, Masoor-2006, Punjab Masoor-00518 and Punjab Masoor-09 resistant with 20 to 46.67% incidence, 4.44 to 12.95% severity index and 9.60 to 24.94% yield reduction compared with highly susceptible (100% incidence) local lentil line (NARC-08-1). The later line was treated with Trichoderma species as antagonists in pot experiment by drenching. The bio-control treatment revealed maximum positive effect of T. harzianum (26.7% incidence, 8.9% severity index and 16.27% yield reduction), followed by T. viride (66.7% incidence, 17.8% severity index and 31.13% yield reduction). On inoculated untreated control, the fungus produced the characteristic wilt symptoms and significantly caused increased severity index, incidence and decreased 100% yield. In vitro evaluation of four fungicides at five concentrations (10, 20, 30, 50 and 100 ppm) revealed maximum inhibition of the test fungus with benomyl (85.9%), followed by thiophanate methyl (81.2%). Determination of the efficacy of two best fungicides viz. benomyl and thiophanate methyl in reducing wilt infection through In vivo seed treatment of NARC-08-1 in previously inoculated potting mixture revealed 100% seed germination and suppressed wilt disease, the most effective being benomyl with 6.7% incidence, 1.5% wilt severity and 17.16% yield reduction compared to the control. The study concluded that the genetic diversity already present in lentil cultivars is an important source, which could be exploited for breeding wilt resistant lentil genotypes. Moreover, being seed and

Medicinal plants--prophylactic and therapeutic options for gastrointestinal and respiratory diseases in calves and piglets? A systematic review.

Science.gov (United States)

Ayrle, Hannah; Mevissen, Meike; Kaske, Martin; Nathues, Heiko; Gruetzner, Niels; Melzig, Matthias; Walkenhorst, Michael

2016-06-06

Gastrointestinal and respiratory diseases in calves and piglets lead to significant economic losses in livestock husbandry. A high morbidity has been reported for diarrhea (calves ≤ 35%; piglets ≤ 50%) and for respiratory diseases (calves ≤ 80%; piglets ≤ 40%). Despite a highly diverse etiology and pathophysiology of these diseases, treatment with antimicrobials is often the first-line therapy. Multi-antimicrobial resistance in pathogens results in international accordance to strengthen the research in novel treatment options. Medicinal plants bear a potential as alternative or additional treatment. Based on the versatile effects of their plant specific multi-component-compositions, medicinal plants can potentially act as 'multi-target drugs'. Regarding the plurality of medicinal plants, the aim of this systematic review was to identify potential medicinal plant species for prevention and treatment of gastrointestinal and respiratory diseases and for modulation of the immune system and inflammation in calves and piglets. Based on nine initial sources including standard textbooks and European ethnoveterinary studies, a total of 223 medicinal plant species related to the treatment of gastrointestinal and respiratory diseases was identified. A defined search strategy was established using the PRISMA statement to evaluate 30 medicinal plant species starting from 20'000 peer-reviewed articles published in the last 20 years (1994-2014). This strategy led to 418 references (257 in vitro, 84 in vivo and 77 clinical trials, thereof 48 clinical trials in veterinary medicine) to evaluate effects of medicinal plants and their efficacy in detail. The findings indicate that the most promising candidates for gastrointestinal diseases are Allium sativum L., Mentha x piperita L. and Salvia officinalis L.; for diseases of the respiratory tract Echinacea purpurea (L.) MOENCH, Thymus vulgaris L. and Althea officinalis L. were found most promising, and Echinacea purpurea (L

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,

Diversity in Betasatellites Associated with Cotton Leaf Curl Disease During Source-To-Sink Movement Through a Resistant Host

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Iftikhar Ali Khan

2016-02-01

Full Text Available Cotton leaf curl is devastating disease of cotton characterized by leaf curling, vein darkening and enations. The disease symptoms are induced by DNA satellite known as Cotton leaf curl Multan betasatellite (CLCuMuB, dominant betasatellite in cotton but another betasatellite known as Chili leaf curl betasatellite (ChLCB is also found associated with the disease. Grafting experiment was performed to determine if host plant resistance is determinant of dominant population of betasatellite in cotton (several distinct strains of CLCuMuB are associated with the disease. Infected scion of Gossypium hirsutum collected from field (the source was grafted on G. arboreum, a diploid cotton species, resistant to the disease. A healthy scion of G. hirsutum (sink was grafted at the top of G. arboreum to determine the movement of virus/betasatellite to upper susceptible scion of G. hirsutum. Symptoms of disease appeared in the upper scion and presence of virus/betasatellite in the upper scion was confirmed via molecular techniques, showing that virus/betasatellite was able to move to upper scion through resistant G. arboreum. However, no symptoms appeared on G. arboreum. Betasatelites were cloned and sequenced from lower scion, upper scion and G. arboreum which show that the lower scion contained both CLCuMuB and ChLCB, however only ChLCB was found in G. arboreum. The upper scion contained CLCuMuB with a deletion of 78 nucleotides (nt in the non-coding region between A-rich sequence and βC1 gene and insertion of 27 nt in the middle of βC1 ORF. This study may help in investigating molecular basis of resistance in G. arboreum.

Insulin Resistance and Alzheimer’s Disease: Bioenergetic Linkages

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Bryan J. Neth

2017-10-01

Full Text Available Metabolic dysfunction is a well-established feature of Alzheimer’s disease (AD, evidenced by brain glucose hypometabolism that can be observed potentially decades prior to the development of AD symptoms. Furthermore, there is mounting support for an association between metabolic disease and the development of AD and related dementias. Individuals with insulin resistance, type 2 diabetes mellitus (T2D, hyperlipidemia, obesity, or other metabolic disease may have increased risk for the development of AD and similar conditions, such as vascular dementia. This association may in part be due to the systemic mitochondrial dysfunction that is common to these pathologies. Accumulating evidence suggests that mitochondrial dysfunction is a significant feature of AD and may play a fundamental role in its pathogenesis. In fact, aging itself presents a unique challenge due to inherent mitochondrial dysfunction and prevalence of chronic metabolic disease. Despite the progress made in understanding the pathogenesis of AD and in the development of potential therapies, at present we remain without a disease-modifying treatment. In this review, we will discuss insulin resistance as a contributing factor to the pathogenesis of AD, as well as the metabolic and bioenergetic disruptions linking insulin resistance and AD. We will also focus on potential neuroimaging tools for the study of the metabolic dysfunction commonly seen in AD with hopes of developing therapeutic and preventative targets.

High-throughput phenotyping of plant resistance to aphids by automated video tracking

NARCIS (Netherlands)

Kloth, K.J.; Broeke, ten C.J.M.; Thoen, H.P.M.; Hanhart-van den Brink, M.; Wiegers, G.L.; Krips, O.E.; Noldus, L.P.J.J.; Dicke, M.; Jongsma, M.A.

2015-01-01

Background: 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 highthroughput, quantitative phenotyping methods. Results: We have developed an

Antagonism between phytohormone signalling underlies the variation in disease susceptibility of tomato plants under elevated CO2

Science.gov (United States)

Zhang, Shuai; Li, Xin; Sun, Zenghui; Shao, Shujun; Hu, Lingfei; Ye, Meng; Zhou, Yanhong; Xia, Xiaojian; Yu, Jingquan; Shi, Kai

2015-01-01

Increasing CO2 concentrations ([CO2]) have the potential to disrupt plant–pathogen interactions in natural and agricultural ecosystems, but the research in this area has often produced conflicting results. Variations in phytohormone salicylic acid (SA) and jasmonic acid (JA) signalling could be associated with variations in the responses of pathogens to plants grown under elevated [CO2]. In this study, interactions between tomato plants and three pathogens with different infection strategies were compared. Elevated [CO2] generally favoured SA biosynthesis and signalling but repressed the JA pathway. The exposure of plants to elevated [CO2] revealed a lower incidence and severity of disease caused by tobacco mosaic virus (TMV) and by Pseudomonas syringae, whereas plant susceptibility to necrotrophic Botrytis cinerea increased. The elevated [CO2]-induced and basal resistance to TMV and P. syringae were completely abolished in plants in which the SA signalling pathway nonexpressor of pathogenesis-related genes 1 (NPR1) had been silenced or in transgenic plants defective in SA biosynthesis. In contrast, under both ambient and elevated [CO2], the susceptibility to B. cinerea highly increased in plants in which the JA signalling pathway proteinase inhibitors (PI) gene had been silenced or in a mutant affected in JA biosynthesis. However, plants affected in SA signalling remained less susceptible to this disease. These findings highlight the modulated antagonistic relationship between SA and JA that contributes to the variation in disease susceptibility under elevated [CO2]. This information will be critical for investigating how elevated CO2 may affect plant defence and the dynamics between plants and pathogens in both agricultural and natural ecosystems. PMID:25657213

Resistant starch: promise for improving human health.

Science.gov (United States)

Birt, Diane F; Boylston, Terri; Hendrich, Suzanne; Jane, Jay-Lin; Hollis, James; Li, Li; McClelland, John; Moore, Samuel; Phillips, Gregory J; Rowling, Matthew; Schalinske, Kevin; Scott, M Paul; Whitley, Elizabeth M

2013-11-01

Ongoing research to develop digestion-resistant starch for human health promotion integrates the disciplines of starch chemistry, agronomy, analytical chemistry, food science, nutrition, pathology, and microbiology. The objectives of this research include identifying components of starch structure that confer digestion resistance, developing novel plants and starches, and modifying foods to incorporate these starches. Furthermore, recent and ongoing studies address the impact of digestion-resistant starches on the prevention and control of chronic human diseases, including diabetes, colon cancer, and obesity. This review provides a transdisciplinary overview of this field, including a description of types of resistant starches; factors in plants that affect digestion resistance; methods for starch analysis; challenges in developing food products with resistant starches; mammalian intestinal and gut bacterial metabolism; potential effects on gut microbiota; and impacts and mechanisms for the prevention and control of colon cancer, diabetes, and obesity. Although this has been an active area of research and considerable progress has been made, many questions regarding how to best use digestion-resistant starches in human diets for disease prevention must be answered before the full potential of resistant starches can be realized.

Insecticide control of vector-borne diseases: when is insecticide resistance a problem?

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Ana Rivero

Full Text Available Many of the most dangerous human diseases are transmitted by insect vectors. After decades of repeated insecticide use, all of these vector species have demonstrated the capacity to evolve resistance to insecticides. Insecticide resistance is generally considered to undermine control of vector-transmitted diseases because it increases the number of vectors that survive the insecticide treatment. Disease control failure, however, need not follow from vector control failure. Here, we review evidence that insecticide resistance may have an impact on the quality of vectors and, specifically, on three key determinants of parasite transmission: vector longevity, competence, and behaviour. We argue that, in some instances, insecticide resistance is likely to result in a decrease in vector longevity, a decrease in infectiousness, or in a change in behaviour, all of which will reduce the vectorial capacity of the insect. If this effect is sufficiently large, the impact of insecticide resistance on disease management may not be as detrimental as previously thought. In other instances, however, insecticide resistance may have the opposite effect, increasing the insect's vectorial capacity, which may lead to a dramatic increase in the transmission of the disease and even to a higher prevalence than in the absence of insecticides. Either way-and there may be no simple generality-the consequence of the evolution of insecticide resistance for disease ecology deserves additional attention.

Tagging of resistance gene(s) to rhizomania disease in sugar beet ...

African Journals Online (AJOL)

The rhizomania disease is one of the most important diseases in Iran and some other parts of the world which potentially could play a role in decreasing sugar yield in fields. One approach to combat with this disease is the use of resistance varieties. This varieties have been identified which are having resistance genes to ...

Pyramiding, alternating or mixing: comparative performances of deployment strategies of nematode resistance genes to promote plant resistance efficiency and durability.

Science.gov (United States)

Djian-Caporalino, Caroline; Palloix, Alain; Fazari, Ariane; Marteu, Nathalie; Barbary, Arnaud; Abad, Pierre; Sage-Palloix, Anne-Marie; Mateille, Thierry; Risso, Sabine; Lanza, Roger; Taussig, Catherine; Castagnone-Sereno, Philippe

2014-02-22

Resistant cultivars are key elements for pathogen control and pesticide reduction, but their repeated use may lead to the emergence of virulent pathogen populations, able to overcome the resistance. Increased research efforts, mainly based on theoretical studies, explore spatio-temporal deployment strategies of resistance genes in order to maximize their durability. We evaluated experimentally three of these strategies to control root-knot nematodes: cultivar mixtures, alternating and pyramiding resistance genes, under controlled and field conditions over a 3-years period, assessing the efficiency and the durability of resistance in a protected crop rotation system with pepper as summer crop and lettuce as winter crop. The choice of the resistance gene and the genetic background in which it is introgressed, affected the frequency of resistance breakdown. The pyramiding of two different resistance genes in one genotype suppressed the emergence of virulent isolates. Alternating different resistance genes in rotation was also efficient to decrease virulent populations in fields due to the specificity of the virulence and the trapping effect of resistant plants. Mixing resistant cultivars together appeared as a less efficient strategy to control nematodes. This work provides experimental evidence that, in a cropping system with seasonal sequences of vegetable species, pyramiding or alternating resistance genes benefit yields in the long-term by increasing the durability of resistant cultivars and improving the long-term control of a soil-borne pest. To our knowledge, this result is the first one obtained for a plant-nematode interaction, which helps demonstrate the general applicability of such strategies for breeding and sustainable management of resistant cultivars against pathogens.

Arabidopsis and Brachypodium distachyon Transgenic Plants Expressing Aspergillus nidulans Acetylesterases Have Decreased Degree of Polysaccharide Acetylation and Increased Resistance to Pathogens1[C][W][OA

Science.gov (United States)

Pogorelko, Gennady; Lionetti, Vincenzo; Fursova, Oksana; Sundaram, Raman M.; Qi, Mingsheng; Whitham, Steven A.; Bogdanove, Adam J.; Bellincampi, Daniela; Zabotina, Olga A.

2013-01-01

The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens. PMID:23463782

Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

Science.gov (United States)

Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L. D.; Anuntalabhochai, S.

2013-07-01

Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60-80 keV to a beam fluence range of 2 × 1016-2 × 1017 ions/cm2. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 106 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11).

Biological changes in Barley mutants resistant to powdery mildew disease

International Nuclear Information System (INIS)

Amer, I. M.; Fahim, M. M.; Moustafa, N. A.

2012-12-01

physiological studies showed that all kinds of chlorophyll (a), (b) and (a + b) content in infected plant were decreased while, the carotenes pigment were increased. Infection generally reduced total sugars content of all resistant mutants. Infected resistant mutant showed more phenols content and peroxidase, polyphenoloxidase activities than healthy ones of the mutants. (Author)

Association analysis for disease resistance to Fusarium oxysporum in cape gooseberry (Physalis peruviana L).

Science.gov (United States)

Osorio-Guarín, Jaime A; Enciso-Rodríguez, Felix E; González, Carolina; Fernández-Pozo, Noé; Mueller, Lukas A; Barrero, Luz Stella

2016-03-18

Vascular wilt caused by Fusarium oxysporum is the most important disease in cape gooseberry (Physalis peruviana L.) in Colombia. The development of resistant cultivars is considered one of the most cost-effective means to reduce the impact of this disease. In order to do so, it is necessary to provide breeders with molecular markers and promising germplasm for introgression of different resistance loci as part of breeding schemes. Here we described an association mapping study in cape gooseberry with the goal to: (i) select promising materials for use in plant breeding and (ii) identify SNPs associated with the cape gooseberry resistance response to the F. oxysporum pathogen under greenhouse conditions, as potential markers for cape gooseberry breeding. We found a total of 21 accessions with different resistance responses within a diversity panel of 100 cape gooseberry accessions. A total of 60,663 SNPs were also identified within the same panel by means of GBS (Genotyping By Sequencing). Model-based population structure and neighbor-joining analyses showed three populations comprising the cape gooseberry panel. After correction for population structure and kinship, we identified SNPs markers associated with the resistance response against F. oxysporum. The identification of markers was based on common tags using the reference genomes of tomato and potato as well as the root/stem transcriptome of cape gooseberry. By comparing their location with the tomato genome, 16 SNPs were found in genes involved in defense/resistance response to pathogens, likewise when compared with the genome of potato, 12 markers were related. The work presented herein provides the first association mapping study in cape gooseberry showing both the identification of promising accessions with resistance response phenotypes and the identification of a set of SNP markers mapped to defense/resistance response genes of reference genomes. Thus, the work also provides new knowledge on candidate

Antibiotics and Resistance: Glossary

Science.gov (United States)

... chromosomes and plasmids. Transposons often carry genes specifying antimicrobial resistance. Virus An extremely small infective agent, visible only with an electron microscope. Viruses can cause disease in humans, animals and plants. Viruses consist of a protein coat ...

The Effect of Temperature and Host Plant Resistance on Population Growth of the Soybean Aphid Biotype 1 (Hemiptera: Aphididae).

Science.gov (United States)

Hough, Ashley R; Nechols, James R; McCornack, Brian P; Margolies, David C; Sandercock, Brett K; Yan, Donglin; Murray, Leigh

2017-02-01

A laboratory experiment was conducted to evaluate direct and indirect effects of temperature on demographic traits and population growth of biotype 1 of the soybean aphid, Aphis glycines Matsumura. Our objectives were to better understand how temperature influences the expression of host plant resistance, quantify the individual and interactive effects of plant resistance and temperature on soybean aphid population growth, and generate thermal constants for predicting temperature-dependent development on both susceptible and resistant soybeans. To assess indirect (plant-mediated) effects, soybean aphids were reared under a range of temperatures (15-30 °C) on soybean seedlings from a line expressing a Rag1 gene for resistance, and life history traits were quantified and compared to those obtained for soybean aphids on a susceptible soybean line. Direct effects of temperature were obtained by comparing relative differences in the magnitude of life-history traits among temperatures on susceptible soybeans. We predicted that temperature and host plant resistance would have a combined, but asymmetrical, effect on soybean aphid fitness and population growth. Results showed that temperature and plant resistance influenced preimaginal development and survival, progeny produced, and adult longevity. There also appeared to be a complex interaction between temperature and plant resistance for survival and developmental rate. Evidence suggested that the level of plant resistance increased at higher, but not lower, temperature. Soybean aphids required about the same number of degree-days to develop on resistant and susceptible plants. Our results will be useful for making predictions of soybean aphid population growth on resistant plants under different seasonal temperatures. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Early evaluation and on field conditions of resistance to Mycosphaerella fijiensis Morelet of plants from Grande naine (AAA cultivar, obtained through out tissue culture and mutations induction

Directory of Open Access Journals (Sweden)

Lourdes R. García

2003-04-01

Full Text Available The present work was carried out in the Plants Biotechnology Institute of the Central University of Las Villas. The plant material from the cv. Grande Naine (AAA was treated with physical mutagenic agents(gamma radiation 60Co source to induce genetic variability. The behaviour of the population to the black Sigatoka was evaluated. A somaclone was selected by its disease resistance and was in vitro multiplied and the plants were acclimatized to evaluate its behaviour facing the disease on greenhouse conditions and in a second cycle of multiplication in the field. The results showed that in the majority of the plants were not found differences respect cv Grande Naine, just one presented similar reaction to cv. ‘FHIA 18’ (AAAB (partially resistant as for the variable evaluated, being obtained a frequency of 0.018% for this character. This plant was named IBP 446. After 60 days of application of the mycelial homogenized of M. fijiensis in micropropagated plants of this somaclone, differences in the respect affectation states were found at susceptible witness in greenhouse conditions. When plants of the IBP 446 were evaluated in a second cycle of multiplication differences were found with the susceptible control only at flowering, while they behaved similar at susceptible control in the crop. Key words: early detection, breeding, mutation, Black Sigatoka

Interdisciplinary Research and Training Program in the Plant Sciences

Energy Technology Data Exchange (ETDEWEB)

Wolk, C.P.

1992-01-01

Research on plants continued. Topics include: Molecular basis of symbiotic plant-microbe interations; enzymatic mechanisms and regulation of plant cell wall biosynthesis; molecular mechanisms that regulate the expression of genes in plants; resistance of plants to environmental stress; studies on hormone biosynthesis and action; plant cell wall proteins; interaction of nuclear and organelle genomes; sensor transduction in plants; molecular mechanisms of trafficking in the plant cell; regulation of lipid metabolism; molecular bases of plant disease resistance mechanisms; biochemical and molecular aspects of plant pathogenesis; developmental biology of nitrogen-fixing cyanobacteria; environmental control of plant development and its relation to plant hormones.

Testing Transgenic Aspen Plants with bar Gene for Herbicide Resistance under Semi-natural Conditions.

Science.gov (United States)

Lebedev, V G; Faskhiev, V N; Kovalenko, N P; Shestibratov, K A; Miroshnikov, A I

2016-01-01

Obtaining herbicide resistant plants is an important task in the genetic engineering of forest trees. Transgenic European aspen plants (Populus tremula L.) expressing the bar gene for phosphinothricin resistance have been produced using Agrobacterium tumefaciens-mediated transformation. Successful genetic transformation was confirmed by PCR analysis for thirteen lines derived from two elite genotypes. In 2014-2015, six lines were evaluated for resistance to herbicide treatment under semi-natural conditions. All selected transgenic lines were resistant to the herbicide Basta at doses equivalent to 10 l/ha (twofold normal field dosage) whereas the control plants died at 2.5 l/ha. Foliar NH4-N concentrations in transgenic plants did not change after treatment. Extremely low temperatures in the third ten-day period of October 2014 revealed differences in freeze tolerance between the lines obtained from Pt of f2 aspen genotypes. Stable expression of the bar gene after overwintering outdoors was confirmed by RT-PCR. On the basis of the tests, four transgenic aspen lines were selected. The bar gene could be used for retransformation of transgenic forest trees expressing valuable traits, such as increased productivity.

Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China.

Directory of Open Access Journals (Sweden)

Haonan Zhang

Full Text Available Transgenic crops producing Bacillus thuringiensis (Bt toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. Here we report data from a 2010 survey showing field-evolved resistance to Cry1Ac of the major target pest, cotton bollworm (Helicoverpa armigera, in northern China. Laboratory bioassay results show that susceptibility to Cry1Ac was significantly lower in 13 field populations from northern China, where Bt cotton has been planted intensively, than in two populations from sites in northwestern China where exposure to Bt cotton has been limited. Susceptibility to Bt toxin Cry2Ab did not differ between northern and northwestern China, demonstrating that resistance to Cry1Ac did not cause cross-resistance to Cry2Ab, and implying that resistance to Cry1Ac in northern China is a specific adaptation caused by exposure to this toxin in Bt cotton. Despite the resistance detected in laboratory bioassays, control failures of Bt cotton have not been reported in China. This early warning may spur proactive countermeasures, including a switch to transgenic cotton producing two or more toxins distinct from Cry1A toxins.

Detection of plant leaf diseases using image segmentation and soft computing techniques

Directory of Open Access Journals (Sweden)

Vijai Singh

2017-03-01

Full Text Available Agricultural productivity is something on which economy highly depends. This is the one of the reasons that disease detection in plants plays an important role in agriculture field, as having disease in plants are quite natural. If proper care is not taken in this area then it causes serious effects on plants and due to which respective product quality, quantity or productivity is affected. For instance a disease named little leaf disease is a hazardous disease found in pine trees in United States. Detection of plant disease through some automatic technique is beneficial as it reduces a large work of monitoring in big farms of crops, and at very early stage itself it detects the symptoms of diseases i.e. when they appear on plant leaves. This paper presents an algorithm for image segmentation technique which is used for automatic detection and classification of plant leaf diseases. It also covers survey on different diseases classification techniques that can be used for plant leaf disease detection. Image segmentation, which is an important aspect for disease detection in plant leaf disease, is done by using genetic algorithm.

Treatment of resistant glomerular diseases with adrenocorticotropic hormone gel: a prospective trial.

Science.gov (United States)

Bomback, Andrew S; Canetta, Pietro A; Beck, Laurence H; Ayalon, Rivka; Radhakrishnan, Jai; Appel, Gerald B

2012-01-01

Adrenocorticotropic hormone (ACTH) has shown promising results in glomerular diseases resistant to conventional therapies, but the reported data have solely been from retrospective, observational studies. In this prospective, open-label study (NCT01129284), 15 subjects with resistant glomerular diseases were treated with ACTH gel (80 units subcutaneously twice weekly) for 6 months. Resistant membranous nephropathy (MN), minimal change disease (MCD), and focal segmental glomerulosclerosis (FSGS) were defined as failure to achieve sustained remission of proteinuria off immunosuppressive therapy with at least 2 treatment regimens; resistant IgA nephropathy was defined as >1 g/g urine protein:creatinine ratio despite maximally tolerated RAAS blockade. Remission was defined as stable or improved renal function with ≥50% reduction in proteinuria to 50% reductions in proteinuria while on ACTH, with proteinuria consistently <1 g/g by 6 months. Three of 15 subjects reported significant steroid-like adverse effects with ACTH, including weight gain and hyperglycemia, prompting early termination of therapy without any clinical response. ACTH gel is a promising treatment for resistant glomerular diseases and should be studied further in controlled trials against currently available therapies for resistant disease. Copyright © 2012 S. Karger AG, Basel.

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.

Diversity and antibiotic resistance of Aeromonas spp. in drinking and waste water treatment plants.

Science.gov (United States)

Figueira, Vânia; Vaz-Moreira, Ivone; Silva, Márcia; Manaia, Célia M

2011-11-01

The taxonomic diversity and antibiotic resistance phenotypes of aeromonads were examined in samples from drinking and waste water treatment plants (surface, ground and disinfected water in a drinking water treatment plant, and raw and treated waste water) and tap water. Bacteria identification and intra-species variation were determined based on the analysis of the 16S rRNA, gyrB and cpn60 gene sequences. Resistance phenotypes were determined using the disc diffusion method. Aeromonas veronii prevailed in raw surface water, Aeromonas hydrophyla in ozonated water, and Aeromonas media and Aeromonas puntacta in waste water. No aeromonads were detected in ground water, after the chlorination tank or in tap water. Resistance to ceftazidime or meropenem was detected in isolates from the drinking water treatment plant and waste water isolates were intrinsically resistant to nalidixic acid. Most of the times, quinolone resistance was associated with the gyrA mutation in serine 83. The gene qnrS, but not the genes qnrA, B, C, D or qepA, was detected in both surface and waste water isolates. The gene aac(6')-ib-cr was detected in different waste water strains isolated in the presence of ciprofloxacin. Both quinolone resistance genes were detected only in the species A. media. This is the first study tracking antimicrobial resistance in aeromonads in drinking, tap and waste water and the importance of these bacteria as vectors of resistance in aquatic environments is discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Increased Levels of Antinutritional and/or Defense Proteins Reduced the Protein Quality of a Disease-Resistant Soybean Cultivar.

Science.gov (United States)

Sousa, Daniele O B; Carvalho, Ana F U; Oliveira, José Tadeu A; Farias, Davi F; Castelar, Ivan; Oliveira, Henrique P; Vasconcelos, Ilka M

2015-07-22

The biochemical and nutritional attributes of two soybean (Glycine max (L.) Merr.) cultivars, one susceptible (Seridó) and the other resistant (Seridó-RCH) to stem canker, were examined to assess whether the resistance to pathogens was related to levels of antinutritional and/or defense proteins in the plant and subsequently affected the nutritional quality. Lectin, urease, trypsin inhibitor, peroxidase and chitinase activities were higher in the resistant cultivar. Growing rats were fed with isocaloric and isoproteic diets prepared with defatted raw soybean meals. Those on the Seridó-RCH diet showed the worst performance in terms of protein quality indicators. Based on regression analysis, lectin, trypsin inhibitor, peroxidase and chitinase appear to be involved in the resistance trait but also in the poorer nutritional quality of Seridó-RCH. Thus, the development of cultivars for disease resistance may lead to higher concentrations of antinutritional compounds, affecting the quality of soybean seeds. Further research that includes the assessment of more cultivars/genotypes is needed.

Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana.

Directory of Open Access Journals (Sweden)

Hushna Ara Naznin

Full Text Available Volatile organic compounds (VOC were extracted and identified from plant growth-promoting fungi (PGPF, Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography-mass spectrometry (GC-MS. Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp. significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst. Subsequently, m-cresol and methyl benzoate (MeBA were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA or Jasmonic acid (JA/ethylene (ET signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases.

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...

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...

Biowaste-derived hydrolysates as plant disease suppressants for oilseed rape

Czech Academy of Sciences Publication Activity Database

Jindřichová, Barbora; Burketová, Lenka; Montoneri, E.; Francavilla, M.

2018-01-01

Roč. 183, MAY 10 (2018), s. 335-342 ISSN 0959-6526 R&D Projects: GA MŠk(CZ) LD14056 Institutional support: RVO:61389030 Keywords : Biogas digestate * Compost * Induced resistance * Leptosphaeria maculans * Oilseed rape Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection OBOR OECD: Plant sciences, botany Impact factor: 5.715, year: 2016

Effects of an inducible aiiA gene on disease resistance in Eucalyptus urophylla × Eucalyptus grandis.

Science.gov (United States)

Ouyang, L J; Li, L M

2016-08-01

N-acyl-homoserine lactones (AHLs) are metabolites of mostly gram-negative bacteria and are critical signaling molecules in bacterial quorum-sensing systems. At threshold concentrations, AHLs can activate the expression of pathogenic genes and induce diseases. Therefore, reducing AHL concentrations is a key point of disease control in plants. AHL-lactonase, which is expressed by aiiA, is widespread in Bacillus sp and can hydrolyze AHLs. In the present study, we cloned aiiA from Bacillus subtilis by PCR. A plant expression vector of aiiA was constructed and name Pcam-PPP3-aiiA, in which expression of aiiA was controlled by the pathogen-inducible plant promoter PPP3. The recombinant plasmid was transferred into Eucalyptus × urophylla × E. grandis by an Agrobacterium-mediated transformation. PCR and Southern blotting showed that aiiA was successfully integrated into the E. urophylla × E. grandis genome and its expression was induced by Ralstonia solanacearum 12 h after inoculation, as shown by reverse transcription-PCR. The transcription efficacy of aiiA increased 43.88-, 30.65-, and 18.95-fold after inoculation with R. solanacearum, Erwinia carotovora ssp. zeae (Sabet) and Cylindrocladium quinqueseptatum, respectively as shown by RT-real-time PCR. Transgenic E.urophylla × E.grandis expressing the AIIA protein exhibited significantly enhanced disease resistance compared to non-transgenic plants by delaying the onset of wilting and reducing the disease index.

RNA-Seq analysis reveals insight into enhanced rice Xa7-mediated bacterial blight resistance at high temperature.

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Stephen P Cohen

Full Text Available Plant disease is a major challenge to agriculture worldwide, and it is exacerbated by abiotic environmental factors. During some plant-pathogen interactions, heat stress allows pathogens to overcome host resistance, a phenomenon which could severely impact crop productivity considering the global warming trends associated with climate change. Despite the importance of this phenomenon, little is known about the underlying molecular mechanisms. To better understand host plant responses during simultaneous heat and pathogen stress, we conducted a transcriptomics experiment for rice plants (cultivar IRBB61 containing Xa7, a bacterial blight disease resistance (R gene, that were infected with Xanthomonas oryzae, the bacterial blight pathogen of rice, during high temperature stress. Xa7-mediated resistance is unusual relative to resistance mediated by other R genes in that it functions better at high temperatures. Using RNA-Seq technology, we identified 8,499 differentially expressed genes as temperature responsive in rice cultivar IRBB61 experiencing susceptible and resistant interactions across three time points. Notably, genes in the plant hormone abscisic acid biosynthesis and response pathways were up-regulated by high temperature in both mock-treated plants and plants experiencing a susceptible interaction and were suppressed by high temperature in plants exhibiting Xa7-mediated resistance. Genes responsive to salicylic acid, an important plant hormone for disease resistance, were down-regulated by high temperature during both the susceptible and resistant interactions, suggesting that enhanced Xa7-mediated resistance at high temperature is not dependent on salicylic acid signaling. A DNA sequence motif similar to known abscisic acid-responsive cis-regulatory elements was identified in the promoter region upstream of genes up-regulated in susceptible but down-regulated in resistant interactions. The results of our study suggest that the plant

Comparison of protein profiles of beech bark disease-resistant or beech bark disease-susceptible American beech

Science.gov (United States)

Mary E. Mason; Marek Krasowski; Judy Loo; Jennifer. Koch

2011-01-01

Proteomic analysis of beech bark proteins from trees resistant and susceptible to beech bark disease (BBD) was conducted. Sixteen trees from eight geographically isolated stands, 10 resistant (healthy) and 6 susceptible (diseased/infested) trees, were studied. The genetic complexity of the sample unit, the sampling across a wide geographic area, and the complexity of...

Accelerating resistance breeding in wheat by integrating marker ...

African Journals Online (AJOL)

Genetic resistance is the simplest and most cost-effective way to guard against disease in plants. The pyramiding of resistance genes is a useful practice in bringing about durable resistance. This study aimed to develop a series of doubled haploid (DH) wheat lines containing combinations of wild species genes for rust ...

THE USE OF PLANTS TO PROTECT PLANTS AND FOOD AGAINST FUNGAL PATHOGENS: A REVIEW.

Science.gov (United States)

Shuping, D S S; Eloff, J N

2017-01-01

Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal diseases, farmers have used fungicides to manage the damage of plant pathogenic fungi. Drawbacks such as development of resistance and environmental toxicity associated with these chemicals have motivated researchers and cultivators to investigate other possibilities. Several databases were accessed to determine work done on protecting plants against plant fungal pathogens with plant extracts using search terms "plant fungal pathogen", "plant extracts" and "phytopathogens". Proposals are made on the best extractants and bioassay techniques to be used. In addition to chemical fungicides, biological agents have been used to deal with plant fungal diseases. There are many examples where plant extracts or plant derived compounds have been used as commercial deterrents of fungi on a large scale in agricultural and horticultural setups. One advantage of this approach is that plant extracts usually contain more than one antifungal compound. Consequently the development of resistance of pathogens may be lower if the different compounds affect a different metabolic process. Plants cultivated using plants extracts may also be marketed as organically produced. Many papers have been published on effective antimicrobial compounds present in plant extracts focusing on applications in human health. More research is required to develop suitable, sustainable, effective, cheaper botanical products that can be used to help overcome the scourge of plant fungal diseases. Scientists who have worked only on using plants to control human and animal fungal pathogens should consider the advantages of focusing on plant fungal pathogens. This approach could not only potentially increase

Evaluation of Lettuce Germplasm Resistance to Gray Mold Disease for Organic Cultivations

Directory of Open Access Journals (Sweden)

Chang Ki Shim

2014-03-01

Full Text Available This study was conducted to evaluate the resistance of 212 accessions of lettuce germplasm to gray mold disease caused by Botrytis cinerea. The lettuce germplasm were composed of five species: Lactuca sativa (193 accessions, L. sativa var. longifolia (2 accessions, L. sativa var. crispa (2 accessions, L. saligna (2 accessions, and L. serriola (1 accession; majority of these originated from Korea, Netherlands, USA, Russia, and Bulgaria. After 35 days of spray inoculation with conidial suspension (3×10⁷ conidia/ml of B. cinerea on the surface of lettuce leaves, tested lettuce germplasm showed severe symptoms of gray mold disease. There were 208 susceptible accessions to B. cinerea counted with 100% of disease incidence and four resistant accessions, IT908801, K000598, K000599, and K021055. Two moderately resistant accessions of L. sativa, K021055 and IT908801, showed 20% of disease incidence of gray mold disease at 45 days after inoculation; and two accessions of L. saligna, K000598 and K000599, which are wild relatives of lettuce germplasm with loose-leaf type, showed complete resistance to B. cinerea. These four accessions are candidates for breeding lettuce cultivars resistant to gray mold disease.

Plant growth and resistance promoted by Streptomyces spp. in tomato.

Science.gov (United States)

Dias, Maila P; Bastos, Matheus S; Xavier, Vanessa B; Cassel, Eduardo; Astarita, Leandro V; Santarém, Eliane R

2017-09-01

Plant Growth Promoting Rhizobacteria (PGPR) represent an alternative to improve plant growth and yield as well as to act as agents of biocontrol. This study characterized isolates of Streptomyces spp. (Stm) as PGPR, determined the antagonism of these isolates against Pectobacterium carotovorum subsp. brasiliensis (Pcb), evaluated the ability of Stm on promoting growth and modulating the defense-related metabolism of tomato plants, and the potential of Stm isolates on reducing soft rot disease in this species. The VOC profile of Stm was also verified. Promotion of plant growth was assessed indirectly through VOC emission and by direct interaction with Stm isolates in the roots. Evaluation of soft rot disease was performed in vitro on plants treated with Stm and challenged with Pcb. Enzymes related to plant defense were then analyzed in plants treated with three selected isolates of Stm, and PM1 was chosen for further Pcb-challenging experiment. Streptomyces spp. isolates displayed characteristics of PGPR. PM3 was the isolate with efficient antagonism against Pcb by dual-culture. Most of the isolates promoted growth of root and shoot of tomato plants by VOC, and PM5 was the isolate that most promoted growth by direct interaction with Stm. Soft rot disease and mortality of plants were significantly reduced when plants were treated with StmPM1. Modulation of secondary metabolism was observed with Stm treatment, and fast response of polyphenoloxidases was detected in plants pretreated with StmPM1 and challenged with Pcb. Peroxidase was significantly activated three days after infection with Pcb in plants pretreated with StmPM1. Results suggest that Streptomyces sp. PM1 and PM5 have the potential to act as PGPR. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Evolution of resistance to a multiple-herbivore community: genetic correlations, diffuse coevolution, and constraints on the plant's response to selection.

Science.gov (United States)

Wise, Michael J; Rausher, Mark D

2013-06-01

Although plants are generally attacked by a community of several species of herbivores, relatively little is known about the strength of natural selection for resistance in multiple-herbivore communities-particularly how the strength of selection differs among herbivores that feed on different plant organs or how strongly genetic correlations in resistance affect the evolutionary responses of the plant. Here, we report on a field study measuring natural selection for resistance in a diverse community of herbivores of Solanum carolinense. Using linear phenotypic-selection analyses, we found that directional selection acted to increase resistance to seven species. Selection was strongest to increase resistance to fruit feeders, followed by flower feeders, then leaf feeders. Selection favored a decrease in resistance to a stem borer. Bootstrapping analyses showed that the plant population contained significant genetic variation for each of 14 measured resistance traits and significant covariances in one-third of the pairwise combinations of resistance traits. These genetic covariances reduced the plant's overall predicted evolutionary response for resistance against the herbivore community by about 60%. Diffuse (co)evolution was widespread in this community, and the diffuse interactions had an overwhelmingly constraining (rather than facilitative) effect on the plant's evolution of resistance. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Defence reactions of plants to fungal pathogens: principles and perspectives, using powdery mildew on cereals as an example

Science.gov (United States)

Heitefuss, Rudolf

2001-06-01

Diseases of crop plants may lead to considerable yield losses. To control fungal diseases, fungicides are used extensively in present-day agricultural production. In order to reduce such external inputs, cultivars with natural resistance to important fungal pathogens are recommended in systems of integrated plant protection. Basic research, including genetics and molecular methods, is required to elucidate the mechanisms by which plants react to an attack by fungal pathogens and successfully defend themselves. This review examines our knowledge with respect to the multicomponent systems of resistance in plants, using powdery mildew on barley as an example. In addition, the question is adressed whether systemic acquired resistance and plants with transgenic resistance may be utilized in future plant protection strategies.

Bioinformatic analysis of the nucleotide binding site-encoding disease-resistance genes in foxtail millet (Setaria italica (L.) Beauv.).

Science.gov (United States)

Zhu, Y B; Xie, X Q; Li, Z Y; Bai, H; Dong, L; Dong, Z P; Dong, J G

2014-08-28

The nucleotide-binding site (NBS) disease-resistance genes are the largest category of plant disease-resistance gene analogs. The complete set of disease-resistant candidate genes, which encode the NBS sequence, was filtered in the genomes of two varieties of foxtail millet (Yugu1 and 'Zhang gu'). This study investigated a number of characteristics of the putative NBS genes, such as structural diversity and phylogenetic relationships. A total of 269 and 281 NBS-coding sequences were identified in Yugu1 and 'Zhang gu', respectively. When the two databases were compared, 72 genes were found to be identical and 164 genes showed more than 90% similarity. Physical positioning and gene family analysis of the NBS disease-resistance genes in the genome revealed that the number of genes on each chromosome was similar in both varieties. The eighth chromosome contained the largest number of genes and the ninth chromosome contained the lowest number of genes. Exactly 34 gene clusters containing the 161 genes were found in the Yugu1 genome, with each cluster containing 4.7 genes on average. In comparison, the 'Zhang gu' genome possessed 28 gene clusters, which had 151 genes, with an average of 5.4 genes in each cluster. The largest gene cluster, located on the eighth chromosome, contained 12 genes in the Yugu1 database, whereas it contained 16 genes in the 'Zhang gu' database. The classification results showed that the CC-NBS-LRR gene made up the largest part of each chromosome in the two databases. Two TIR-NBS genes were also found in the Yugu1 genome.

Transgenic expression of lactoferrin imparts enhanced resistance to head blight of wheat caused by Fusarium graminearum.

Science.gov (United States)

Han, Jigang; Lakshman, Dilip K; Galvez, Leny C; Mitra, Sharmila; Baenziger, Peter Stephen; Mitra, Amitava

2012-03-09

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. Using the tools of plant genetic engineering, a broad-spectrum antimicrobial gene was tested for resistance against head blight caused by Fusarium graminearum Schwabe, a devastating disease of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) that reduces both grain yield and quality. A construct containing a bovine lactoferrin cDNA was used to transform wheat using an Agrobacterium-mediated DNA transfer system to express this antimicrobial protein in transgenic wheat. Transformants were analyzed by Northern and Western blots to determine lactoferrin gene expression levels and were inoculated with the head blight disease fungus F. graminearum. Transgenic wheat showed a significant reduction of disease incidence caused by F. graminearum compared to control wheat plants. The level of resistance in the highly susceptible wheat cultivar Bobwhite was significantly higher in transgenic plants compared to control Bobwhite and two untransformed commercial wheat cultivars, susceptible Wheaton and tolerant ND 2710. Quantification of the expressed lactoferrin protein by ELISA in transgenic wheat indicated a positive correlation between the lactoferrin gene expression levels and the levels of disease resistance. Introgression of the lactoferrin gene into elite commercial wheat, barley and other susceptible cereals may enhance resistance to F. graminearum.