scholarly journals Grafting for Disease Resistance

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1673-1676 ◽  
Author(s):  
Stephen R. King ◽  
Angela R. Davis ◽  
Wenge Liu ◽  
Amnon Levi
Keyword(s):  
Disease Resistance ◽  
Root Rot ◽  
Pathogen Resistance ◽  
Soilborne Pathogens ◽  
Pathogen Population ◽  
Soil Fumigant ◽  
Soil Microbial ◽  
The Future ◽  
Microbial Environment ◽  
Pathogen Populations

The primary purpose of grafting vegetables worldwide has been to provide resistance to soilborne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soilborne pathogens even more important in the future. The major disease problems addressed by grafting include fusarium wilt, bacterial wilt, verticillium wilt, monosporascus root rot, and nematodes. Grafting has also been shown in some instances to increase tolerance to foliar fungal diseases, viruses, and insects. If the area devoted to grafting increases in the future, there will likely be a shift in the soil microbial environment that could lead to the development of new diseases or changes in the pathogen population of current diseases. This shift in pathogen populations could lead to the development of new diseases or the re-emergence of previously controlled diseases. Although grafting has been demonstrated to control many common diseases, the ultimate success will likely depend on how well we monitor for changes in pathogen populations and other unexpected consequences.

scholarly journals Bioinformatic-Based Approaches for Disease-Resistance Gene Discovery in Plants

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2259
Author(s):  
Andrea Fernandez-Gutierrez ◽  
Juan J. Gutierrez-Gonzalez
Keyword(s):  
Disease Resistance ◽  
Resistance Genes ◽  
Gene Annotation ◽  
Pathogen Resistance ◽  
Limiting Factors ◽  
Disease Resistance Gene ◽  
R Genes ◽  
Nucleotide Binding Sites ◽  
Bioinformatic Tools ◽  
Computer Based

Pathogens are among the most limiting factors for crop success and expansion. Thus, finding the underlying genetic cause of pathogen resistance is the main goal for plant geneticists. The activation of a plant’s immune system is mediated by the presence of specific receptors known as disease-resistance genes (R genes). Typical R genes encode functional immune receptors with nucleotide-binding sites (NBS) and leucine-rich repeat (LRR) domains, making the NBS-LRRs the largest family of plant resistance genes. Establishing host resistance is crucial for plant growth and crop yield but also for reducing pesticide use. In this regard, pyramiding R genes is thought to be the most ecologically friendly way to enhance the durability of resistance. To accomplish this, researchers must first identify the related genes, or linked markers, within the genomes. However, the duplicated nature, with the presence of frequent paralogues, and clustered characteristic of NLRs make them difficult to predict with the classic automatic gene annotation pipelines. In the last several years, efforts have been made to develop new methods leading to a proliferation of reports on cloned genes. Herein, we review the bioinformatic tools to assist the discovery of R genes in plants, focusing on well-established pipelines with an important computer-based component.

scholarly journals Ribonuclease activity as a new prospective disease resistance marker in potato

2019 ◽  
Vol 22 (8) ◽  
pp. 987-991 ◽  
Author(s):  
E. A. Trifonova ◽  
S. M. Ibragimova ◽  
O. A. Volkova ◽  
V. K. Shumny ◽  
A. V. Kochetov
Keyword(s):  
Disease Resistance ◽  
Late Blight ◽  
Systemic Acquired Resistance ◽  
Higher Plants ◽  
Wide Spectrum ◽  
Acquired Resistance ◽  
Pathogen Resistance ◽  
Rnase Activity ◽  
Measured Parameter ◽  
Resistance To Viruses

Disease resistance is an important characteristic for each variety of potato, and the search for pathogen resistance markers is one of the primary tasks of plant breeding. Higher plants possess a wide spectrum of enzymes catalyzing the hydrolysis of nucleic acids; it is believed that protection against pathogens is the most probable function of the enzymes. RNases are actively involved in several immune systems of higher plants, for example, systemic acquired resistance (SAR) and genetic silencing, hence RNase activity in plant leaves, as a relatively easily measured parameter, can serve as a good marker for the selection of pathogen resistant varieties. We have analyzed sixteen varieties of potatoes permitted for use on the territory of the Russian Federation and tested the correlation of the level of variety­specifc ribonuclease (RNase) activity with such economically valuable traits as maturity and resistance to viruses, late blight and common scab. In general, the level of RNase activity was variety­specifc, which was confrmed by very small values of average squared error for the majority of tested varieties. We have detected a statistically signifcant positive correlation of RNase activity in potato leaves with increased resistance of varieties to phytopathogenic viruses, a negative correlation with resistance to scab and an absence of a signifcant connection with maturity and resistance to late blight, regardless of the organ affected by the oomycete. Thus, the level of RNase activity in potato leaves can be used as a selective marker for resistance to viruses, while varieties with increased RNase activity should be avoided when selecting resistance to scab.

scholarly journals WEEDS AS POTENTIAL HOSTS FOR FUNGAL ROOT PATHOGENS OF WATERMELON

2019 ◽  
Vol 32 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Rui Sales Júnior ◽  
Ana Paula Medeiros dos Santos Rodrigues ◽  
Andreia Mitsa Paiva Negreiros ◽  
Márcia Michelle de Queiroz Ambrósio ◽  
Hailton da Silva Barboza ◽  
...  
Keyword(s):  
Root Rot ◽  
Citrullus Lanatus ◽  
Phytopathogenic Fungi ◽  
Soilborne Pathogens ◽  
Weed Species ◽  
Amaranthus Spinosus ◽  
Trianthema Portulacastrum ◽  
Different Types ◽  
Vine Decline ◽  
Boerhavia Diffusa

ABSTRACT Many watermelon (Citrullus lanatus) diseases are caused by soilborne pathogens in Brazil and worldwide. The goal of this study was to identify and quantify the frequency of phytopathogenic fungi associated with watermelon root rot and vine decline that were also present in the roots of weeds in the major watermelon production regions in the state of Rio Grande do Norte, Brazil. We collected root samples from 10 of the most prevalent weed species in 16 watermelon producing areas. The plants were identified and their frequencies in the fields were calculated. The fungi found in the weed roots were isolated and the main genera associated with watermelon vine decline were identified. We identified 13 weed species belonging to nine botanical families. The weed species with the highest frequencies found in the field were Amaranthus spinosus (25.0%), Trianthema portulacastrum (18.8%), Commelina sp. (18.8%), and Boerhavia diffusa (12.5%). The fungi Macrophomina, Rhizoctonia, and Monosporascus were isolated from the roots of the weed plants. While Macrophomina was isolated from 12 different types of plants, Rhizoctonia and Monosporascus were isolated from four and two different plant species, respectively.

scholarly journals Seasonal Variation in the Rhizosphere and Non-Rhizosphere Microbial Community Structures and Functions of Camellia yuhsienensis Hu

2020 ◽  
Vol 8 (9) ◽  
pp. 1385
Author(s):  
Jun Li ◽  
Ziqiong Luo ◽  
Chenhui Zhang ◽  
Xinjing Qu ◽  
Ming Chen ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Microbial Community ◽  
High Throughput Sequencing ◽  
Sulfur Metabolism ◽  
Pathogen Resistance ◽  
High Yield ◽  
Glutathione Metabolism ◽  
Oilseed Crop ◽  
Soil Microbial ◽  
Bacteria And Fungi

Camellia yuhsienensis Hu, endemic to China, is a predominant oilseed crop, due to its high yield and pathogen resistance. Past studies have focused on the aboveground parts of C. yuhsienensis, whereas the microbial community of the rhizosphere has not been reported yet. This study is the first time to explore the influence of seasonal variation on the microbial community in the rhizosphere of C. yuhsienensis using high-throughput sequencing. The results showed that the dominant bacteria in the rhizosphere of C. yuhsienensis were Chloroflexi, Proteobacteria, Acidobacteria, Actinobacteria, and Planctomycetes, and the dominant fungi were Ascomycota, Basidiomycota, and Mucoromycota. Seasonal variation has significant effects on the abundance of the bacterial and fungal groups in the rhizosphere. A significant increase in bacterial abundance and diversity in the rhizosphere reflected the root activity of C. yuhsienensis in winter. Over the entire year, there were weak correlations between microorganisms and soil physiochemical properties in the rhizosphere. In this study, we found that the bacterial biomarkers in the rhizosphere were chemoorganotrophic Gram-negative bacteria that grow under aerobic conditions, and fungal biomarkers, such as Trichoderma, Mortierella, and Lecanicillium, exhibited protection against pathogens in the rhizosphere. In the rhizosphere of C. yuhsienensis, the dominant functions of the bacteria included nitrogen metabolism, oxidative phosphorylation, glycine, serine and threonine metabolism, glutathione metabolism, and sulfur metabolism. The dominant fungal functional groups were endophytes and ectomycorrhizal fungi of a symbiotroph trophic type. In conclusion, seasonal variation had a remarkable influence on the microbial communities and functions, which were also significantly different in the rhizosphere and non-rhizosphere of C. yuhsienensis. The rhizosphere of C. yuhsienensis provides suitable conditions with good air permeability that allows beneficial bacteria and fungi to dominate the soil microbial community, which can improve the growth and pathogen resistance of C. yuhsienensis.

scholarly journals Subfamily-Specific Specialization of RGH1/MLA Immune Receptors in Wild Barley

2019 ◽  
Vol 32 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Takaki Maekawa ◽  
Barbara Kracher ◽  
Isabel M. L. Saur ◽  
Makoto Yoshikawa-Maekawa ◽  
Ronny Kellner ◽  
...  
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Geographic Origin ◽  
Coiled Coil ◽  
Hordeum Spontaneum ◽  
R Gene ◽  
Powdery Mildew Fungus ◽  
Signaling Domain ◽  
Pathogen Populations ◽  
Signaling Domains

The barley disease resistance (R) gene locus mildew locus A (Mla) provides isolate-specific resistance against the powdery mildew fungus Blumeria graminis hordei and has been introgressed into modern cultivars from diverse germplasms, including the wild relative Hordeum spontaneum. Known Mla disease resistance specificities to B. graminis hordei appear to encode allelic variants of the R gene homolog 1 (RGH1) family of nucleotide-binding domain and leucine-rich repeat (NLR) proteins. Here, we sequenced and assembled the transcriptomes of 50 H. spontaneum accessions representing nine populations distributed throughout the Fertile Crescent. The assembled Mla transcripts exhibited rich sequence diversity, linked neither to geographic origin nor population structure, and could be grouped into two similar-sized subfamilies based on two major N-terminal coiled-coil (CC) signaling domains that are both capable of eliciting cell death. The presence of positively selected sites located mainly in the C-terminal leucine-rich repeats of both MLA subfamilies, together with the fact that both CC signaling domains mediate cell death, implies that the two subfamilies are actively maintained in the population. Unexpectedly, known MLA receptor variants that confer B. graminis hordei resistance belong exclusively to one subfamily. Thus, signaling domain divergence, potentially as adaptation to distinct pathogen populations, is an evolutionary signature of functional diversification of an immune receptor. [Formula: see text] Copyright © 2018 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals Presence of Root Rot Reduces Stability of Norway Spruce (Picea abies): Results of Static Pulling Tests in Latvia

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 416 ◽  
Author(s):  
Oskars Krisans ◽  
Roberts Matisons ◽  
Steffen Rust ◽  
Natalija Burnevica ◽  
Lauma Bruna ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Root Rot ◽  
Rotation Period ◽  
Wind Damage ◽  
Individual Tree ◽  
Study Region ◽  
Secondary Failure ◽  
The Future ◽  
Spruce Stands ◽  
Individual Trees

Storms are the main abiotic disturbance in European forests, effects of which are expected to intensify in the future, hence the importance of forest stand stability is increasing. The predisposition of Norway spruce to wind damage appears to be enhanced by pathogens such as Heterobasidion spp., which reduce stability of individual trees. However, detailed information about the effects of the root rot on the stability of individual trees across diverse soil types is still lacking. The aim of the study was to assess the effect of root rot on the individual tree stability of Norway spruce growing on drained peat and mineral soils. In total, 77 Norway spruce trees (age 50–80 years) growing in four stands were tested under static loading. The presence of Heterobasidion spp. had a significant negative effect on the bending moment at primary and secondary failure of the tested trees irrespectively of soil type. This suggests increased legacy effects (e.g., susceptibility to pathogens and pests due to fractured roots and altered water uptake) of storms. Damaged trees act as weak spots increasing the susceptibility of stands to wind damage, thus forming a negative feedback loop and contributing to an ongoing decline in vitality of Norway spruce stands following storms in the study region in the future. Accordingly, the results support the importance of timely identification of the decayed trees, lowering stand density and/or shortening rotation period as the measures to counteract the increasing effects of storms on Norway spruce stands.

scholarly journals Exogenous Application of Harpin Protein Hpa1 onto Pinellia ternata Induces Systemic Resistance Against Tobacco Mosaic Virus

2020 ◽  
Vol 110 (6) ◽  
pp. 1189-1198
Author(s):  
Defu Wang ◽  
Baoxia Wang ◽  
Jiangran Wang ◽  
Shuting Wang ◽  
Weiyu Wang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Large Scale ◽  
Pathogen Resistance ◽  
Field Application ◽  
Systemic Resistance ◽  
Pinellia Ternata ◽  
Related Substances ◽  
Harpin Protein

The harpin protein Hpa1 has various beneficial effects in plants, such as promoting plant growth and inducing pathogen resistance. Our previous study found that Hpa1 could significantly alleviate the mosaic symptoms of tobacco mosaic virus (TMV) in Pinellia ternata, indicating that Hpa1 can effectively stimulate resistance. Here, the potential mechanism of disease resistance and field applicability of Hpa1 against TMV in P. ternata were further investigated. The results showed that 15 µg ml−1 Hpa1 had stronger antiviral activity than the control, and its protective effect was better than its curative effect. Furthermore, Hpa1 could significantly induce an increase in defense-related enzyme activity, including polyphenol oxidase, peroxidase, catalase, and superoxide dismutase, as well as increase the expression of disease resistance-related genes (PR1, PR3, PR5, and PDF1.2). Concurrently, Hpa1 significantly increased the content of some disease resistance-related substances, including hydrogen peroxide, phenolics, and callose, whereas the content of malondialdehyde was reduced. In addition, field application analysis demonstrated that Hpa1 could effectively elicit a defense response against TMV in P. ternata. Our findings propose a mechanism by which Hpa1 can prevent TMV infection in Pinellia by inducing systemic resistance, thereby providing an environmentally friendly approach for the use of Hpa1 in large-scale applications to improve TMV resistance in Pinellia.

scholarly journals Multiple Disease Resistance Loci Affect Soilborne Disease Resistance in Tobacco (Nicotiana tabacum)

2017 ◽  
Vol 107 (9) ◽  
pp. 1055-1061 ◽  
Author(s):  
Katherine Drake-Stowe ◽  
Nicolas Bakaher ◽  
Simon Goepfert ◽  
Berangere Philippon ◽  
Regis Mark ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Dna Markers ◽  
Phytophthora Nicotianae ◽  
Soilborne Pathogens ◽  
High Positive Correlation ◽  
Soilborne Disease ◽  
Breeding Populations ◽  
Multiple Disease Resistance ◽  
Phytophthora Resistance ◽  
Genomic Regions

Phytophthora nicotianae and Ralstonia solanacearum are two of the most important pathogens affecting tobacco worldwide. Greater insight regarding genetic systems controlling resistance to these two soilborne pathogens, as well as identification of DNA markers associated with genomic regions controlling this resistance, could aid in variety development. An evaluation of 50 historical tobacco lines revealed a high positive correlation between resistances to the two pathogens, preliminarily suggesting that some genomic regions may confer resistance to both pathogens. A quantitative trait loci (QTL) mapping experiment designed to investigate the genetic control of soilborne disease resistance of highly resistant ‘K346’ tobacco identified four QTL significantly associated with resistance to P. nicotianae (explaining 60.0% of the observed phenotypic variation) and three QTL to be associated with R. solanacearum resistance (explaining 50.3% of the observed variation). The two QTL with the largest effect on Phytophthora resistance were also found to be the QTL with the greatest effects on resistance to Ralstonia. This finding partially explains previously observed associations between resistances to these two pathogens among U.S. current cultivars and within breeding populations. Further study is needed to determine whether these relationships are due to the same genes (i.e., pleiotropy) or favorable coupling-phase linkages that have been established over time.

Puccinia striiformis in Australia: a review of the incursion, evolution, and adaptation of stripe rust in the period 1979 - 2006

2007 ◽  
Vol 58 (6) ◽  
pp. 567 ◽  
Author(s):  
C. R. Wellings
Keyword(s):  
Stripe Rust ◽  
Chemical Control ◽  
Puccinia Striiformis ◽  
Cool Temperature ◽  
Pathogen Population ◽  
European Origin ◽  
Yield And Quality ◽  
Eastern Australia ◽  
Major Shift ◽  
Pathogen Populations

The wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici; Pst) was first detected in Australia in 1979. The features of the initial pathotype suggested that it was of European origin, and later work provided evidence that it was most likely transmitted as adherent spores on travellers’ clothing. Despite long-held views that this cool temperature pathogen would not adapt to Australian conditions, Pst became endemic and progressively adapted to commercial wheat production through step-wise mutation. Several of these mutant pathotypes became frequent in the Pst population, causing widespread infection and significant costs to production (yield and quality losses; chemical control expenditure) in certain cultivars and seasons. Pathotype evolution, including adaptation to native barley grass (Hordeum spp.) populations, is described. The occurrence of an exotic pathotype of Pst in Western Australia in 2002, and its subsequent spread to eastern Australia, represented a major shift in the pathogen population. This pathotype dominated pathogen populations throughout Australia from 2003, with chemical control expenditure estimated at AU$40–90 million annually. Another exotic introduction was detected in 1998. Initial data indicated that certain isolates collected from barley grass were highly avirulent to wheat differentials, with the exception of partial virulence to Chinese 166. Further seedling tests revealed that these isolates, tentatively designated barley grass stripe rust (BGYR), were virulent on several Australian barleys, notably those of Skiff parentage. Data, including molecular studies, suggest that BGYR is a new forma specialis of P. striiformis. Field nurseries indicate that BGYR is likely to have little impact on commercial barley, although this may change with further pathotype evolution or the release of susceptible cultivars.

scholarly journals E-beam irradiation for the control of Phytophthora nicotianae var. nicotianae in stonewool cubes

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 679-682 ◽  
Author(s):  
Magdalena Ptaszek ◽  
Leszek B. Orlikowski ◽  
Wojciech Migdał ◽  
Urszula Gryczka
Keyword(s):  
Electron Beam ◽  
Root Rot ◽  
Irradiation Dose ◽  
Electron Beam Irradiation ◽  
Potato Dextrose Agar ◽  
Phytophthora Nicotianae ◽  
Beam Irradiation ◽  
Pathogen Population ◽  
Stem Base ◽  
Tomato Seedlings

Abstract Effectiveness of electron beam irradiation was evaluated against Phytophthora nicotianae var. nicotianae, the causal agent of stem base and root rot of tomato. In laboratory trials, irradiation of 7-day-old Phytophthora cultures growing on potato-dextrose-agar (PDA) medium with 1 kGy resulted in the disintegration of the pathogen’s hyphae. Increasing the irradiation dose to 3 kGy caused decay of the hyphae. Irradiation of infested stonewool with 5 kGy caused decrease of the pathogen population about 5 times. Application of 20 kGy completely eliminated the pathogen from stonewool. Irradiation of substratum resulted in significant increase of tomato seedlings healthiness, especially when the dose 20 kGy was applied.

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