scholarly journals Screening for PVYN-Wi Resistance in Kenyan Potato Cultivars

2021 ◽  
Author(s):  
John Onditi ◽  
Moses Nyongesa ◽  
René van der Vlugt
Keyword(s):  
Resistance Genes ◽  
Severe Infection ◽  
Potato Cultivars ◽  
Post Inoculation ◽  
Yield Losses ◽  
Pvy Resistance ◽  
Screening Experiments ◽  
Prevalent Strain ◽  
Potato Crops ◽  
Resistant Genotypes

AbstractOver the past decades, two new strains of potato virus Y (PVYN-Wi (Wilga) and PVYNTN) have been the most widely distributed worldwide in potato crops (Solanum tuberosum L.). Effective resistance genes comprehensive against all the known strains of the virus are available in some commercial cultivars. However, not all resistance genes in cultivars have been challenged by the new PVY strains to confirm effectiveness of the resistances available. This study was set to identify PVY resistant genotypes and estimate yield losses in potato cultivars in Kenya. PVYN-Wi was used for PVY resistance screening because it was the most prevalent strain in Kenya and also was found to produce more severe infection in Kenyan potato genotypes compared with PVYO (the second most prevalent strain). Three cultivars, Kenya Karibu, Sherekea and Unica, were identified as resistant because they did not get PVY infections over three seasons of both greenhouse and field screening experiments. In addition, two early generation breeding clones were identified as resistant at 28 days post-inoculation. In susceptible cultivars Dutch Robyjn, Nyayo and Kenya Mpya, PVYN-Wi infection caused yield losses of 21.6, 39.0 and 53.1%, respectively, after three seasons. This study demonstrated the necessity to screen for PVY resistance based on the most prevalent PVY strains and to make an informed decision on the usefulness of current levels of resistance in potato cultivars.

scholarly journals Effect of Colletotrichum coccodes on Potato Yield, Tuber Quality, and Stem Colonization During Spring and Autumn

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 561-565 ◽  
Author(s):  
Leah Tsror (Lahkim) ◽  
Orly Erlich ◽  
Marina Hazanovsky
Keyword(s):  
Vascular Tissue ◽  
Potato Yield ◽  
Potato Cultivars ◽  
Colletotrichum Coccodes ◽  
Tuber Quality ◽  
Yield Losses ◽  
Inoculation Methods ◽  
Significant Yield ◽  
Potato Crops

The response of five potato cultivars to Colletotrichum coccodes was tested in artificially inoculated fields for three consecutive spring and autumn seasons during 1994 to 1996. Significant yield reductions (22 to 30%) were observed in all tested cultivars. Results varied between years, but yield losses were more severe in autumn than in spring. Stem infections of plants were observed 90 days after planting on the surface of the stem and in vascular tissue. C. coccodes inoculation also resulted in reduction of the quality of daughter tubers. Cultivars Cara and Nicola were found to be less susceptible to tuber infection than Alpha, Desiree, and Agria. The incidence of diseased daughter tubers was higher when the soil was infested than when the foliage was inoculated. C. coccodes contamination of dry stems at harvest (in inoculated plots) was relatively high in all cultivars, with no difference between inoculation methods. Thus, C. coccodes infection not only affects potato yield and the quality of potatoes for seed and consumption, but also contaminates soil and serves as an important source of inoculum for future potato crops.

Corrigendum to: Integrated transcriptomics and metabolomics reveal induction of hierarchies of resistance genes in potato against late blight

2016 ◽  
Vol 43 (12) ◽  
pp. 1205 ◽  
Author(s):  
Kalenahalli N. Yogendra ◽  
Ajjamada C. Kushalappa
Keyword(s):  
Late Blight ◽  
Resistance Genes ◽  
Quantitative Resistance ◽  
Potato Production ◽  
Metabolic Reprogramming ◽  
Specific Gene ◽  
Molecular Events ◽  
Pathway Regulation ◽  
Molecular And Biochemical Mechanisms ◽  
Resistant Genotypes

Late blight caused by Phytophthora infestans is a devastating disease affecting potato production worldwide. The quantitative resistance is durable, but the underlying molecular and biochemical mechanisms are poorly understood, limiting its application in breeding. Integrated transcriptomics and metabolomics approach was used for the first time to study the hierarchies of molecular events occurring, following inoculation of resistant and susceptible potato genotypes with P. infestans. RNA sequencing revealed a total of 4216 genes that were differentially expressed in the resistant than in the susceptible genotype. Genes that were highly expressed and associated with their biosynthetic metabolites that were highly accumulated, through metabolic pathway regulation, were selected. Quantitative real-time PCR was performed to confirm the RNA-seq expression levels. The induced leucine-rich repeat receptor-like kinases (LRR-RLKs) are considered to be involved in pathogen recognition. These receptor genes are considered to trigger downstream oxidative burst, phytohormone signalling-related genes, and transcription factors that regulated the resistance genes to produce resistance related metabolites to suppress the pathogen infection. It was noted that several resistance genes in metabolic pathways related to phenylpropanoids, flavonoids, alkaloids and terpenoid biosynthesis were strongly induced in the resistant genotypes. The pathway specific gene induction provided key insights into the metabolic reprogramming of induced defence responses in resistant genotypes.

scholarly journals Evolution of Physiologic Races and Virulence of Puccinia striiformis on Wheat in Syria and Lebanon

Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 499-504 ◽  
Author(s):  
A. H. Yahyaoui ◽  
M. S. Hakim ◽  
M. El Naimi ◽  
N. Rbeiz
Keyword(s):  
Resistance Genes ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Wheat Breeding ◽  
Natural Conditions ◽  
Breeding Programs ◽  
Land Race ◽  
Physiologic Races ◽  
Resistant Genotypes

Virulence-avirulence phenotypes of Puccinia striiformis isolates collected in Lebanon and Syria were determined on seedlings of the wheat-yellow rust differential genotypes. We found 25 and 11 physiologic races over 6 years (1994 to 1999) in Syria and Lebanon, respectively. The composition of physiologic races found in Syria and Lebanon differed greatly between 1994 and 1999. Races identified in 1999, such as 230E150 and 230E134, have wider spectra of virulence on resistant genotypes than races collected in 1994. In Lebanon, three races were found in 1994 compared with six races in 1999. Yellow rust differential genotypes were used in a trap nursery to monitor yellow rust populations under natural conditions. Races identified from cultivars in the trap nursery in Syria and Lebanon, and from land race cultivars in Iraq, were recovered among the races identified from farm fields. Yellow rust samples were collected from Yemen, and none of the races identified from Yemen samples were identical to those in Syria and Lebanon. Virulence frequencies in the yellow rust population on the differential genotypes tested in the trap nurseries were above 70% for some resistance genes. Yellow rust populations in Syria and Lebanon have diverse virulence phenotypes. P. striiformis populations appear to be changing over, and this would be an important consideration for wheat breeding programs in the region.

scholarly journals Identification of Phaeoisariopsis griseola pathotypes from five States in Brazil

2002 ◽  
Vol 27 (1) ◽  
pp. 78-81 ◽  
Author(s):  
ALOISIO SARTORATO
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Resistance Genes ◽  
Leaf Spot ◽  
Angular Leaf Spot ◽  
Phaeoisariopsis Griseola ◽  
Moist Chamber ◽  
Differential Cultivars ◽  
Pathogenic Variability ◽  
Resistant Genotypes

Due to the increased importance of angular leaf spot of common bean (Phaseolus vulgaris) in Brazil, monitoring the pathogenic variability of its causal agent (Phaeoisariopsis griseola) is the best strategy for a breeding program aimed at developing resistant genotypes. Fifty one isolates of P. griseola collected in five Brazilian States were tested on a set of 12 international differential cultivars in the greenhouse. When inoculated plants showed symptoms but no sporulation was observed, they were transferred to a moist chamber for approximately 20-24 h. After this period of time, if no sporulation was observed, the plants were considered resistant; otherwise, they were considered susceptible. From the fifty-one tested isolates, seven different pathotypes were identified. No Andean pathotypes were identified; consequently, all isolates were classified as Middle American pathotypes. Pathotype 63-31 was the most widespread. Pathotype 63-63 overcame resistance genes present in all differential cultivars and also the resistance gene(s) present in the cultivar AND 277. This fact has important implications for breeding angular leaf spot resistance in beans, and suggests that searching for new resistance genes to angular leaf spot must be pursued.

scholarly journals Bacteriophages: A Revisited Strategy for the Treatment of Severe Bacterial Infections

2020 ◽  
Vol 2 (3) ◽  
pp. 78-79
Author(s):  
Roberto Badaro
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Phage Therapy ◽  
Bacterial Pathogen ◽  
Severe Infection ◽  
Current Increase ◽  
Therapeutic Alternative ◽  
The Ideal

Bacteriophages are viruses that infect and parasitize bacteria. The current increase in the incidence of antibiotic resistance in human bacteria has favoredthe study of phages as a therapeutic alternative (phage therapy). Phage therapy is defined as the administration of virulent phages directly to a patient to lyse the bacterial pathogen that is causing a clinically severe infection. The ideal route of administration and modification of bacteriopaghes genetically to deactivate bacterial resistance genes is the next future to antibiotic recovery sensitivity of MDR organisms.

Fertiliser practice and yield losses in process potato crops grown in Canterbury, New Zealand

2016 ◽  
Vol 44 (1) ◽  
pp. 41-57 ◽  
Author(s):  
JB Reid ◽  
BP Searle ◽  
SM Sinton ◽  
A Michel ◽  
ED Meenken ◽  
...  
Keyword(s):  
New Zealand ◽  
Yield Losses ◽  
Potato Crops

Resistance, tolerance, and yield of western black cottonwood infected by Melampsora rust

1992 ◽  
Vol 22 (2) ◽  
pp. 183-192 ◽  
Author(s):  
J. Wang ◽  
B.J. van der Kamp
Keyword(s):  
Disease Severity ◽  
Volume Growth ◽  
Severe Infection ◽  
Dry Weight ◽  
Stem Volume ◽  
Yield Losses ◽  
Black Cottonwood ◽  
Total Dry Weight ◽  
Significant Discovery ◽  
The Relationship

Potted ramets of 14 western black cottonwood (Populustrichocarpa Torr. & Gray) clones from southern British Columbia were inoculated with Melampsoraoccidentalis H. Jacks to produce a range of disease severities, and their size and dry weight were determined after 1 or 2 years. Response to inoculation varied significantly between clones. Clones from drier interior locations were less resistant than those from coastal or moister interior locations. Local- (within leaf) or systemic-induced resistance was not detected. Yield (total dry weight) decreased linearly with disease severity. Percent reduction in yield was greater than the cumulative percent leaf area infected for all clones. Yield losses were substantial: dry weights of ramets with disease severity levels similar to those experienced by natural cottonwood populations were about 75% of controls; heavily infected ramets were <50% of controls. Stem:root ratios increased rapidly with increasing disease severity in all clones, and at significantly different rates. Severe infection resulted in substantial mortality in the following winter and reduced initial stem volume growth in the following growing season. Tolerance, defined as the relationship between disease severity and yield, varied significantly between clones. The most significant discovery of this study was that tolerance and resistance were correlated, greater tolerance being associated with reduced resistance. The concepts of resistance, tolerance, and disease hazard, as quantified in this study, can be used to predict yield and to select the most appropriate clones for different disease hazard conditions.

scholarly journals Blackberry and raspberry are alternative resistance sources to fire blight

2017 ◽  
Vol 97 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Ozer Calis ◽  
Cetin Cekic ◽  
Serhat Kara ◽  
Demet Celik Ertekin
Keyword(s):  
Bacterial Growth ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Pathogen ◽  
Post Inoculation ◽  
Resistance Sources ◽  
Pathogenicity Tests ◽  
Susceptibility And Resistance ◽  
Resistant Genotypes ◽  
Moderate Susceptibility

Erwinia amylovora causes fire blight mainly on pear, apple and quince trees. This bacterial pathogen also infects other Rosaceous plants, such as blackberry and raspberry. A race structure was established between an isolate of E. amylovora and berries using 40 wild blackberry and 7 wild raspberry genotypes. In pathogenicity tests, wild blackberry and raspberry genotypes had three phenotypic reactions: enhanced susceptibility, moderate susceptibility and resistance. We noted a higher bacterial growth of over 300 × 109 cfu mL-1 in plants with enhanced susceptibility, with resistant genotypes showing a bacterial growth of around 150 × 109 cfu mL-1. These results are also associated with symptoms observed at 29 days post-inoculation. This resistance is being evaluated to control fire blight.

scholarly journals Strain-Specific Hypersensitive and Extreme Resistance Phenotypes Elicited by Potato virus Y Among 39 Potato Cultivars Released in Three World Regions Over a 117-Year Period

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 185-196 ◽  
Author(s):  
Roger A. C. Jones ◽  
Stuart J. Vincent
Keyword(s):  
Potato Virus ◽  
Potato Virus Y ◽  
Secondary Infection ◽  
Potato Cultivars ◽  
Symptom Expression ◽  
Extreme Resistance ◽  
Potato Plants ◽  
Pvy Resistance ◽  
World Regions ◽  
Healthy Seed

Strain-specific hypersensitive (HR) and extreme resistance (ER) phenotypes elicited in potato plants by three Potato virus Y (PVY) isolates in strain groups PVYO (BL and DEL3) and PVYD (KIP1) were studied. PVYO and PVYD isolates elicit HR genes Ny or putative Nd, respectively, and all three isolates elicit ER gene Ry. They were inoculated to 39 Australasian, European, or North American potato cultivars released over a 117-year period and harvested tubers were replanted. Both primary and secondary symptoms were recorded. Two European cultivars always developed ER following sap and graft inoculation and, thus, carried comprehensive PVY resistance gene Ry. One Australasian and two European cultivars always developed susceptible phenotypes and, thus, lacked genes Ry, Ny, and putative Nd. Sap inoculation with isolate KIP1 elicited localized HR (LHR) in 31 cultivars and both LHR and systemic HR (SHR) in three others; thus, all carried putative Nd. Isolates BL and DEL3 both elicited susceptible phenotypes in 11 of these 34 cultivars but LHR alone, SHR alone, or both LHR and SHR in the other 23 which, therefore, all carry Ny. With these two isolates, SHR expression ranged from very severe to very weak, with the greatest numbers of isolate–cultivar combinations occurring in the severe category with BL (n = 11) and moderate category (n = 12) with DEL3. Within the same isolate–cultivar combination, overall, SHR symptom expression was weaker with secondary than primary infection. With both primary and secondary infection, SHR expression was most severe with KIP1 and weakest with DEL3. Genes Ny and putative Nd were present in cultivars released between 1939 and 2010 or 1893 and 2010, respectively, occurring in cultivars from all three world regions. These findings have important implications concerning breeding new PVY-resistant potato cultivars, especially for countries lacking healthy seed potato stocks, or where subsistence farmers cannot afford them. An alternative to including gene Ry is incorporating as many strain-specific PVY resistance genes as possible.

Sign in / Sign up

Export Citation Format

Share Document