scholarly journals Defense Response to Hemileia vastatrix in Susceptible Grafts onto Resistant Rootstock of Coffea arabica

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1621
Author(s):  
Edgar Couttolenc-Brenis ◽  
Gloria Carrión ◽  
Luc Villain ◽  
Fernando Ortega-Escalona ◽  
Martín Mata-Rosas ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Defense Response ◽  
Coffea Arabica ◽  
Early Stage ◽  
Leaf Tissue ◽  
Susceptible Cultivar ◽  
Hemileia Vastatrix ◽  
Qrt Pcr ◽  
Coffee Leaf Rust ◽  
Resistant Rootstock

The use of resistant cultivars and fungicides are common methods to control coffee leaf rust (CLR), the main disease that affects the Arabica coffee crop. In this study, we evaluated the response of grafted and ungrafted plants during the early stage of Hemileia vastatrix infection. We used ungrafted plants of Oro Azteca (resistant cultivar) and Garnica (susceptible cultivar), and grafted plants, combining both as rootstock and graft (Garnica/Oro Azteca and Oro Azteca/Garnica). All plants were inoculated with H. vastatrix uredospores, and we quantified the development of fungal structures in the leaf tissue of inoculated plants using qRT-PCR to measure relative expression of two pathogenesis recognition genes (CaNDR1 and CaNBS-LRR) and three genes associated with the salicylic acid (SA) pathway (CaNPR1, CaPR1 and CaPR5). In Garnica grafted on Oro Azteca, the fungal structures recorded were significantly less than in Garnica ungrafted plants. In addition, the expression of defense-related genes in grafted plants was higher than in ungrafted plants. Our results indicate that the defense response to CLR is strongly influenced by the rootstock employed.

Genetic analysis of partial resistance to coffee leaf rust (Hemileia vastatrix Berk & Br.) introgressed into the cultivated Coffea arabica L. from the diploid C. canephora species

Euphytica ◽  
2008 ◽  
Vol 167 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Juan Carlos Herrera P. ◽  
Gabriel Alvarado A. ◽  
Hernando A. Cortina G. ◽  
Marie-Christine Combes ◽  
Gladys Romero G. ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Leaf Rust ◽  
Partial Resistance ◽  
Coffea Arabica ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust ◽  
Coffea Arabica L

scholarly journals Prehaustorial local resistance to coffee leaf rust in a Mexican cultivar involves expression of salicylic acid-responsive genes

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8345
Author(s):  
Edgar Couttolenc-Brenis ◽  
Gloria L. Carrión ◽  
Luc Villain ◽  
Fernando Ortega-Escalona ◽  
Daniel Ramírez-Martínez ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Leaf Rust ◽  
Defense Mechanisms ◽  
Early Recognition ◽  
Infected Leaf ◽  
Disease Resistance Gene ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust ◽  
Subsequent Activation ◽  
Leaf Disks

Background In Mexico, coffee leaf rust (CLR) is the main disease that affects the Arabica coffee crop. In this study, the local response of two Mexican cultivars of Coffea arabica (Oro Azteca and Garnica) in the early stages of Hemileia vastatrix infection was evaluated. Methods We quantified the development of fungal structures in locally-infected leaf disks from both cultivars, using qRT-PCR to measure the relative expression of two pathogenesis recognition genes (CaNDR1 and CaNBS-LRR) and three genes associated with the salicylic acid (SA)-related pathway (CaNPR1, CaPR1, and CaPR5). Results Resistance of the cv. Oro Azteca was significantly higher than that of the cv. Garnica, with 8.2% and 53.3% haustorial detection, respectively. In addition, the non-race specific disease resistance gene (CaNDR1), a key gene for the pathogen recognition, as well as the genes associated with SA, CaNPR1, CaPR1, and CaPR5, presented an increased expression in response to infection by H. vastatrix in cv. Oro Azteca if comparing with cv. Garnica. Our results suggest that Oro Azteca’s defense mechanisms could involve early recognition of CLR by NDR1 and the subsequent activation of the SA signaling pathway.

scholarly journals Candidate genes in coffee (Coffea arabica L.) leaves associated with rust (Hemileia vastatrix Berk. & Br) stress

2019 ◽  
Author(s):  
Fabián Echeverría-Beirute ◽  
Seth C. Murray ◽  
Benoit Bertrand ◽  
Patricia E. Klein
Keyword(s):  
Gene Expression ◽  
Coffea Arabica ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Hemileia Vastatrix ◽  
Fruit Thinning ◽  
Expression Of Genes ◽  
Coffee Leaf Rust ◽  
Host Tolerance ◽  
Related Proteins

Background. Coffee leaf rust (CLR) caused by Hemileia vastatrix Berk. & Br, is one of the most threatening diseases for Coffea arabica L. It is hypothesized that host tolerance to CLR relies on non-race-specific resistance genes. Methods. This study evaluated gene expression in leaves of two susceptible coffee cultivars (one inbred and one F1 hybrid) under different stress conditions: rust control (fungicide and untreated) and fruit thinning (thinned and un-thinned) treatments. RNA-seq analysis focused on the association of differentially expressed genes (DEGs) with CLR and associated the effect of the most significant genes into the phenotype, using regression and prediction statistical models. Results. Gene expression and gene ontology (GO) analysis allowed identification of 100 genes associated with quantitative traits. From these, 88 were correlated with rust incidence, rust severity, and rust sporulation. The expression of genes coding for pathogenesis-related proteins increased positively with rust incidence in the inbred, while genes involved in homoeostasis and broader cell wall structuring processes were upregulated in the F1 hybrid. The enriched gene functions and associations revealed that a possible hypersensitive response (HR) in the inbred and a systemic acquired resistance (SAR) in the F1 hybrid were involved in the tolerance mechanisms to CLR stress. This is the first study to demonstrate the specific interactions between CLR and host at a molecular level, useful for identifying control targets for breeding perennial species.

scholarly journals Candidate genes in coffee (Coffea arabica L.) leaves associated with rust (Hemileia vastatrix Berk. & Br) stress

2019 ◽  
Author(s):  
Fabián Echeverría-Beirute ◽  
Seth C. Murray ◽  
Benoit Bertrand ◽  
Patricia E. Klein
Keyword(s):  
Gene Expression ◽  
Coffea Arabica ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Hemileia Vastatrix ◽  
Fruit Thinning ◽  
Expression Of Genes ◽  
Coffee Leaf Rust ◽  
Host Tolerance ◽  
Related Proteins

Background. Coffee leaf rust (CLR) caused by Hemileia vastatrix Berk. & Br, is one of the most threatening diseases for Coffea arabica L. It is hypothesized that host tolerance to CLR relies on non-race-specific resistance genes. Methods. This study evaluated gene expression in leaves of two susceptible coffee cultivars (one inbred and one F1 hybrid) under different stress conditions: rust control (fungicide and untreated) and fruit thinning (thinned and un-thinned) treatments. RNA-seq analysis focused on the association of differentially expressed genes (DEGs) with CLR and associated the effect of the most significant genes into the phenotype, using regression and prediction statistical models. Results. Gene expression and gene ontology (GO) analysis allowed identification of 100 genes associated with quantitative traits. From these, 88 were correlated with rust incidence, rust severity, and rust sporulation. The expression of genes coding for pathogenesis-related proteins increased positively with rust incidence in the inbred, while genes involved in homoeostasis and broader cell wall structuring processes were upregulated in the F1 hybrid. The enriched gene functions and associations revealed that a possible hypersensitive response (HR) in the inbred and a systemic acquired resistance (SAR) in the F1 hybrid were involved in the tolerance mechanisms to CLR stress. This is the first study to demonstrate the specific interactions between CLR and host at a molecular level, useful for identifying control targets for breeding perennial species.

Hemileia vastatrix. [Descriptions of Fungi and Bacteria].

1964 ◽  
Author(s):  
G. F. Laundon
Keyword(s):  
Leaf Rust ◽  
Geographical Distribution ◽  
Long Range ◽  
Coffea Arabica ◽  
Lower Surface ◽  
Spore Dispersal ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust ◽  
Rain Splash ◽  
Yellowish Orange

Abstract A description is provided for Hemileia vastatrix. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Coffea arabica, C. canephora, C. liberica, and other Coffea spp. DISEASE: Coffee leaf rust. Produces yellowish-orange, powdery, rounded blotches on the lower surface of the leaves, which may coalesce with others to form an irregularly shaped lesion, accompanied by a chlorosis of the upper surface. With age, the centre of the leaf turns dark brown and dies, followed by premature defoliation and die-back of the branches. Has also on rare occasions been recorded on berries and young shoots. GEOGRAPHICAL DISTRIBUTION: Africa, Asia, Australasia, end Oceania (CMI Map 5). TRANSMISSION: Earlier workers [Ward, J. Linn. Soc. (Bot.) 19: 299-335, 1882, Mayne (12: 285)] attributed spore dispersal to wind but more recent investigations have emphasised the role played by rain-splash over short distances (Bock, Trans. Brit. Mycol. Soc. 45: 289-300, 1962). Air currents may be implicated in long-range inter-continental dispersal (Wellman, 1957). Two species of thrips have been found feeding on and aiding the dispersal of urediospores in India (40: 467) and urediospores have also been observed to be mechanically transported on the bodies of two species of hymenopterous parasites of larvae of cecidomyid midges commonly found feeding on urediospores in Kenya (Crowe, Trans. Brit. Mycol. Soc. 46: 24-26, 1963).

Timing and Frequency of Spraying for Control of Coffee Leaf Rust in Southern India

1969 ◽  
Vol 5 (2) ◽  
pp. 117-123 ◽  
Author(s):  
K. C. Ananth
Keyword(s):  
Leaf Rust ◽  
Leaf Spot ◽  
Coffea Arabica ◽  
Hemileia Vastatrix ◽  
Early Season ◽  
Leaf Disease ◽  
Coffee Leaf Rust ◽  
Mysore State ◽  
Hot Weather ◽  
Coorg District

SummaryTo study control of Hemileia vastatrix leaf disease in Coffea arabica L., an experiment was run for a year in Coorg District of Mysore State. Three and four early-season sprays coupled with two mid-season ones gave a reasonable control, as evaluated by leaf spot counts, but a high proportion of rust-affected leaves were retained on the bushes. Infection commenced in the hot weather, immediately after showers, and the number of infected leaves appears to have been more important than the average leaf spot counts. Control of leaf disease up to December, and a late incidence of the rust during January, may not affect crop prospects appreciably. It is suggested that reduced early sprays coupled with pre-monsoon and timely mid-season schedules should reasonably control the incidence of rust.

The fine structure of the coffee leaf rust, Hemileia vastatrix

1974 ◽  
Vol 52 (6) ◽  
pp. 1363-1367 ◽  
Author(s):  
Luisete Rijo ◽  
J. A. Sargent
Keyword(s):  
Fine Structure ◽  
Golgi Apparatus ◽  
Leaf Rust ◽  
Wall Thickness ◽  
Coffea Arabica ◽  
Rust Fungi ◽  
The Body ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust

The fine structure of two races of Hemileia vastatrix that cause leaf rust in Coffea arabica is similar in many respects to earlier descriptions of other rust fungi. Certain features, however, are distinctive. Both hyphae and haustoria contain occasional tubular complexes composed of tubules about 300 Å in diameter. These might function as a Golgi apparatus. The haustorium neck ring incorporates the entire wall thickness at its proximal end, but distally only the outer and innermost layers of the wall are involved. The invaginated host plasmalemma, which surrounds the body of the haustorium, has a furrowed surface and in the adjacent haustorial sheath fibrillar elements are prominent. The plasmalemma furrows and the sheath fibrillar elements are discussed in relation to the organization of the structure of the sheath and absorption of materials through it.

scholarly journals New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María del Carmen H. Rodríguez ◽  
Harry C. Evans ◽  
Lucas M. de Abreu ◽  
Davi M. de Macedo ◽  
Miraine K. Ndacnou ◽  
...  
Keyword(s):  
New Species ◽  
Cloud Forest ◽  
Elongation Factor ◽  
Classical Biological Control ◽  
Hemileia Vastatrix ◽  
Translation Elongation ◽  
Coffee Leaf Rust ◽  
Novel Taxa ◽  
Coffee Plants ◽  
Wild Coffee

AbstractA survey for species of the genus Trichoderma occurring as endophytes of Coffea, and as mycoparasites of coffee rusts (Hemileia), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of Trichoderma were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (tef1), rpb2 and cal for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of Trichoderma species endophytic in both wild and cultivated Coffea, and mycoparasitic on Hemileia rusts. Sixteen species were delimited, including four novel taxa which are described herein: T. botryosum, T. caeruloviride, T. lentissimum and T. pseudopyramidale. Two of these new species, T. botryosum and T. pseudopyramidale, constituted over 60% of the total isolations, predominantly from wild C. arabica in Ethiopian cloud forest. In sharp contrast, not a single isolate of Trichoderma was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘Trichoderma void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African Trichoderma isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from Hemileia vastatrix, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.

scholarly journals Comparison of saliva with healthcare workers- and patient-collected swabs in the diagnosis of COVID-19 in a large cohort

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mitnala Sasikala ◽  
Yelamanchili Sadhana ◽  
Ketavarapu Vijayasarathy ◽  
Anand Gupta ◽  
Sarala Kumari Daram ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Early Stage ◽  
Cost Effective ◽  
Hospitalized Patients ◽  
Detection Sensitivity ◽  
Nasopharyngeal Swab ◽  
Predictive Values ◽  
Qrt Pcr ◽  
Asymptomatic Patients ◽  
Sensitivity Specificity

Abstract Background A considerable amount of evidence demonstrates the potential of saliva in the diagnosis of COVID-19. Our aim was to determine the sensitivity of saliva versus swabs collected by healthcare workers (HCWs) and patients themselves to assess whether saliva detection can be offered as a cost-effective, risk-free method of SARS-CoV-2 detection. Methods This study was conducted in a hospital involving outpatients and hospitalized patients. A total of 3018 outpatients were tested. Of these, 200 qRT-PCR-confirmed SARS-CoV-2-positive patients were recruited for further study. In addition, 101 SARS-CoV-2-positive hospitalized patients with symptoms were also enrolled in the study. From outpatients, HCWs collected nasopharyngeal swabs (NPS), saliva were obtained. From inpatients, HCWs collected swabs, patient-collected swabs, and saliva were obtained. qRT-PCR was performed to detect SARS-CoV-2 by TAQPATH assay to determine the sensitivity of saliva detection. Sensitivity, specificity and positive/negative predictive values (PPV, NPV) of detecting SARS-CoV-2 were calculated using MedCalc. Results Of 3018 outpatients (asymptomatic: 2683, symptomatic: 335) tested by qRT-PCR, 200 were positive (males: 140, females: 60; aged 37.9 ± 12.8 years; (81 asymptomatic, 119 symptomatic). Of these, saliva was positive in 128 (64%); 39 of 81 asymptomatic (47%),89 of 119 symptomatic patients (74.8%). Sensitivity of detection was 60.9% (55.4–66.3%, CI 95%), with a negative predictive value of 36%(32.9–39.2%, CI 95%).Among 101 hospitalized patients (males:65, females: 36; aged 53.48 ± 15.6 years), with HCW collected NPS as comparator, sensitivity of saliva was 56.1% (47.5–64.5, CI 95%), specificity 63.5%(50.4–75.3, CI95%) with PPV of 77.2% and NPV of 39.6% and that of self-swab was 52.3%(44–60.5%, CI95%), specificity 56.6% (42.3–70.2%, CI95%) with PPV 77.2% and NPV29.7%. Comparison of positivity with the onset of symptoms revealed highest detection in saliva on day 3 after onset of symptoms. Additionally, only saliva was positive in 13 (12.8%) hospitalized patients. Conclusion Saliva which is easier to collect than nasopharyngeal swab is a viable alternate to detect SARS-COV-2 in symptomatic patients in the early stage of onset of symptoms. Although saliva is currently not recommended for screening asymptomatic patients, optimization of collection and uniform timing of sampling might improve the sensitivity enabling its use as a screening tool at community level.

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