The colonization ratio: a measure of pathogen invasiveness and host resistance in Verticillium wilt of alfalfa

1989 ◽  
Vol 67 (2) ◽  
pp. 365-370 ◽  
Author(s):  
A. G. Newcombe ◽  
Y. A. Papadopoulos ◽  
Jane Robb ◽  
B. R. Christie
Keyword(s):  
Disease Resistance ◽  
Verticillium Wilt ◽  
Host Resistance ◽  
Quantitative Measure ◽  
Pathogen Resistance ◽  
Symptom Expression ◽  
Symptom Evaluation ◽  
Spore Trapping ◽  
Disease Free ◽  
Trapping Sites

Seeds of four alfalfa cultivars were grown and the plants cloned by rooting cuttings. Individual plants were root-dip inoculated with Verticillium albo-atrum Reinke and Berthold, and scored for relative pathogen resistance by symptom evaluation and reisolation of the fungus during a 7-month period. Nine individual plants were selected: two were resistant to colonization and symptom expression, two remained colonized but were resistant to symptom expression, and five were susceptible. Disease-free cuttings of each selected plant were infused with a mixture of conidia and red vinyl particles which mark primary spore trapping sites. At 168-h postinoculation the colonization ratio was determined for each sample. The colonization ratio is a reliable quantitative measure of invasiveness which is calculated by scoring a section of tissue for the number of secondary colonization sites established per primary trapping site in a given unit of time. The colonization ratio values of the nine selected plants were correlated with the level of disease resistance as determined by two methods: (i) symptom evaluation and pathogen resiolation, and (ii) genetic S1 analysis. The colonization ratio, a new measure of fungal invasiveness and host resistance, might be useful in the breeding and assessment of alfalfa cultivars with resistance to Verticillium wilt.

Vascular coating: a barrier to colonization by the pathogen in Verticillium wilt of tomato

1989 ◽  
Vol 67 (2) ◽  
pp. 600-607 ◽  
Author(s):  
Jane Robb ◽  
D. A. Powell ◽  
P. F. S. Street
Keyword(s):  
Disease Resistance ◽  
Verticillium Wilt ◽  
Water Samples ◽  
Light Microscope ◽  
Trapping Site ◽  
Symptom Expression ◽  
Susceptible Tomato ◽  
Ve Gene ◽  
Verticillium Albo Atrum

Massive infusion of conidia of Verticillium albo-atrum Reinke & Berthier induced synchronous secretion of vascular coating in the petiolar xylem vessels of resistant and susceptible tomato near-isolines. More coating formed earlier in resistant than in susceptible plants. In the susceptible plants secretion was delayed in colonized trapping site vessels, but initiated in surrounding uncolonized ones. Controls were infused with water. Samples were quantified by light microscope assay techniques at 18, 48, and 120 h postinoculation for the following parameters: (i) delayed coating effect, (ii) overall coating capacity, and (iii) ability of fungus to "escape" laterally from trapping site vessels. The results showed that susceptibility to Verticillium was absolutely correlated with the presence of the delayed coating effect in the plant and increased ability of the fungus to spread laterally. Treatment of inoculated resistant plants with an inhibitor of coating secretion resulted in conversion to the susceptible phenotype. The progeny of a genetic backcross for the dominant (Ve) and recessive (ve) alleles at the Ve locus (Velve × velve) were assayed for the same parameters as well as for disease resistance based on symptom expression. The results confirmed the previous observations and suggested that in tomato the delayed phenotype is recessive. The data strongly supports two hypotheses: (i) coating forms a barrier against fungal penetration and (ii) the timing of the coating response in trapping site vessels results, directly or indirectly, from expression of the Ve gene.

scholarly journals Wood Tannins - Isolation and Significance in Host Resistance to Verticillium Wilt Disease

1967 ◽  
Vol 20 (2) ◽  
pp. 475 ◽  
Author(s):  
TC Somers ◽  
AF Harrison
Keyword(s):  
Heart Disease ◽  
Disease Resistance ◽  
Verticillium Wilt ◽  
Host Resistance ◽  
Total Phenolics ◽  
Resistance Mechanisms ◽  
Wilt Disease ◽  
Fivefold Increase ◽  
Verticillium Albo Atrum

Apricot trees often recover from the "black heart" disease incited by the fungus Verticillium albo-atrum Reinke & Berthold, and a characteristic of such resistant trees is that the infected wood becomes dark brown to black in colour (Dufrenoy and Dufrenoy 1927). The fungus dies 1-6 months after it has colonized the wood (Taylor 1963). Analysis of total phenolics by the Folin-Denis assay showed an approximate fivefold increase (to about 60 mgjg wood) compared with that of uninfected wood of the same branch, and suggested their involvement in disease resistance mechanisms.

scholarly journals Dynamic characteristics and functional analysis provide new insights into long non-coding RNA responsive to Verticillium dahliae infection in Gossypium hirsutum

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Guoning Wang ◽  
Xingfen Wang ◽  
Yan Zhang ◽  
Jun Yang ◽  
Zhikun Li ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Verticillium Wilt ◽  
Dynamic Characteristics ◽  
Target Genes ◽  
Acid Metabolism ◽  
Expression Profiles ◽  
Enrichment Analysis ◽  
Alpha Linolenic Acid ◽  
Non Coding Rna ◽  
Long Non Coding Rna

Abstract Background Verticillium wilt is a widespread and destructive disease, which causes serious loss of cotton yield and quality. Long non-coding RNA (lncRNA) is involved in many biological processes, such as plant disease resistance response, through a variety of regulatory mechanisms, but their possible roles in cotton against Verticillium dahliae infection remain largely unclear. Results Here, we measured the transcriptome of resistant G. hirsutum following infection by V. dahliae and 4277 differentially expressed lncRNAs (delncRNAs) were identified. Localization and abundance analysis revealed that delncRNAs were biased distribution on chromosomes. We explored the dynamic characteristics of disease resistance related lncRNAs in chromosome distribution, induced expression profiles, biological function, and these lncRNAs were divided into three categories according to their induced expression profiles. For the delncRNAs, 687 cis-acting pairs and 14,600 trans-acting pairs of lncRNA-mRNA were identified, which indicated that trans-acting was the main way of Verticillium wilt resistance-associated lncRNAs regulating target mRNAs in cotton. Analyzing the regulation pattern of delncRNAs revealed that cis-acting and trans-acting lncRNAs had different ways to influence target genes. Gene Ontology (GO) enrichment analysis revealed that the regulatory function of delncRNAs participated significantly in stimulus response process, kinase activity and plasma membrane components. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that delncRNAs participated in some important disease resistance pathways, such as plant-pathogen interaction, alpha-linolenic acid metabolism and plant hormone signal transduction. Additionally, 21 delncRNAs and 10 target genes were identified as being involved in alpha-linolenic acid metabolism associated with the biosynthesis of jasmonic acid (JA). Subsequently, we found that GhlncLOX3 might regulate resistance to V. dahliae through modulating the expression of GhLOX3 implicated in JA biosynthesis. Further functional analysis showed that GhlncLOX3-silenced seedlings displayed a reduced resistance to V. dahliae, with down-regulated expression of GhLOX3 and decreased content of JA. Conclusion This study shows the dynamic characteristics of delncRNAs in multiaspect, and suggests that GhlncLOX3-GhLOX3-JA network participates in response to V. dahliae invasion. Our results provide novel insights for genetic improvement of Verticillium wilt resistance in cotton using lncRNAs.

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 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 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 Verticillium dahliae effector VDAL protects MYB6 from degradation by interacting with PUB25/26 E3 ligases for enhancing Verticillium wilt resistance in Arabidopsis

2021 ◽  
Author(s):  
Zhizhong Gong ◽  
Junsheng Qi ◽  
Aifang Ma ◽  
Dingpeng Zhang ◽  
Guangxing Wang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Plant Resistance ◽  
Plant Disease Resistance ◽  
Plant Disease ◽  
Effector Proteins ◽  
In Planta ◽  
E3 Ligases

Verticillium wilt is a severe plant disease, increasing the plant resistance to this disease is a critical challenge worldwide. Here, we report that the Verticillium dahliae (V. dahliae)-secreted Aspf2-like protein VDAL causes leaf wilting when applied to cotton leaves in vitro, but enhances the resistance to V. dahliae when overexpressed in Arabidopsis or cotton. VDAL interacts with Arabidopsis E3 ligases PUB25 and PUB26 (PUBs) and is ubiquitinated by PUBs in vitro. However, VDAL is not degraded by PUBs in planta. Besides, the pub25 pub26 shows higher resistance to V. dahliae than the wild type. PUBs interact with the transcription factor MYB6 in a yeast two-hybrid screen. MYB6 promotes plant resistance to Verticillium wilt while PUBs ubiquitinate MYB6 and mediate its degradation. VDAL competes with MYB6 for binding to PUBs, and the role of VDAL in increasing wilt disease depends on MYB6. These results suggest that plants evolute a strategy to utilize the invaded effector protein VDAL to resist the V. dahliae infection without causing a hypersensitive response. This study provides the molecular mechanism for plants increasing disease resistance when overexpressing some effector proteins, and may promote searching for more genes from pathogenic fungi or bacteria to engineer plant disease resistance.

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