Durable Resistance in Crops: Should the Concept of Physiological Races Die?

1983 ◽  
pp. 41-44 ◽  
Author(s):  
J. E. Vanderplank
Keyword(s):  
Durable Resistance ◽  
Physiological Races

scholarly journals Variabilidad patogénica de Colletotrichum lindemuthianum y resistencia en germoplasma de Phaseolus vulgaris L. de Ecuador

2018 ◽  
Vol 29 (1) ◽  
pp. 19 ◽  
Author(s):  
Diego Rodríguez-Ortega ◽  
Laura Vega-Jiménez ◽  
Ángel Rubén Murillo-Ilbay ◽  
Eduardo Peralta-Idrovo ◽  
Juan Carlos Rosas-Sotomayor
Keyword(s):  
Phaseolus Vulgaris ◽  
Resistance Genes ◽  
Durable Resistance ◽  
Colletotrichum Lindemuthianum ◽  
Phaseolus Vulgaris L ◽  
Sources Of Resistance ◽  
Improved Varieties ◽  
Physiological Races ◽  
Resistant Varieties ◽  
Pathogenic Variability

Anthracnose caused by Colletotrichum lindemuthianum is one of the most economically important diseases of bean (Phaseolus vulgaris L.) cultivation in Ecuador. The best control alternative is the use of resistant varieties. C. lindemuthianum presents great pathogenic variability, which hinders the development of varieties with a lasting resistance, therefore, the knowledge of the presence and distribution of the physiological races of the pathogen and the identification of resistance genes are key to developing varieties with broad and lasting resistance. The objective of this research was to determine the pathogenic variability of C. lindemuthianum and to evaluate the resistance of Ecuadorian bean germplasm. The research was carried out between 2013 and 2014. Seventeen isolates of C. lindemuthianum from northern central Ecuador were characterized by the inoculation of a group of twelve standard differential bean varieties. Among the analyzed samples, thirteen races were identified; five of those races had not been previously reported in the country. The differential G2333 (Co-42, Co-52 and Co-7) presented resistance to every characterized races in Ecuador. In addition, twenty - one improved varieties and elite bean lines were evaluated with sixteen of the seventeen isolates, three genotypes were identified (TB2, TB3 and INIAP 485 Urcuquí) with resistance to the mentioned isolates, which can be used as sources of resistance to Anthracnose. The identified sources of resistance in this study will allow to plan the development of bean varieties with broad and durable resistance to C. lindemuthianum.

Sunflower durable resistance to downy mildew

2019 ◽  
Vol 1 (80) ◽  
pp. 93-97
Author(s):  
Sergei Gontcharov ◽  
◽  
Natalya Goloschapova ◽  
Keyword(s):  
Downy Mildew ◽  
Durable Resistance

Antimicrobial Peptides - Small but Mighty Weapons for Plants to Fight Phytopathogens

2019 ◽  
Vol 26 (10) ◽  
pp. 720-742 ◽  
Author(s):  
Kaushik Das ◽  
Karabi Datta ◽  
Subhasis Karmakar ◽  
Swapan K. Datta
Keyword(s):  
Antimicrobial Peptides ◽  
Durable Resistance ◽  
Defense Responses ◽  
Defense System ◽  
Biotechnological Potential ◽  
Functional Aspects ◽  
Low Concentrations ◽  
Wide Range ◽  
Vital Component ◽  
Pathogen Entry

Antimicrobial Peptides (AMPs) have diverse structures, varied modes of actions, and can inhibit the growth of a wide range of pathogens at low concentrations. Plants are constantly under attack by a wide range of phytopathogens causing massive yield losses worldwide. To combat these pathogens, nature has armed plants with a battery of defense responses including Antimicrobial Peptides (AMPs). These peptides form a vital component of the two-tier plant defense system. They are constitutively expressed as part of the pre-existing first line of defense against pathogen entry. When a pathogen overcomes this barrier, it faces the inducible defense system, which responds to specific molecular or effector patterns by launching an arsenal of defense responses including the production of AMPs. This review emphasizes the structural and functional aspects of different plant-derived AMPs, their homology with AMPs from other organisms, and how their biotechnological potential could generate durable resistance in a wide range of crops against different classes of phytopathogens in an environmentally friendly way without phenotypic cost.

Identification of anthracnose races in Manitoba and Ontario from 2005 to 2015 and their reactions on Ontario dry bean cultivars

2020 ◽  
Vol 100 (1) ◽  
pp. 40-55 ◽  
Author(s):  
Robert L. Conner ◽  
Greg J. Boland ◽  
Chris L. Gillard ◽  
Yongyan Chen ◽  
Xuechan Shan ◽  
...  
Keyword(s):  
Durable Resistance ◽  
Colletotrichum Lindemuthianum ◽  
Frequency Of Occurrence ◽  
Phaseolus Vulgaris L ◽  
Dry Bean ◽  
Bean Cultivar ◽  
New Information ◽  
The World ◽  
New Races ◽  
Resistance Spectrum

Anthracnose, caused by the fungus Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara, is one of the most destructive diseases of dry bean (Phaseolus vulgaris L.) in the world. Between 2005 and 2015, commercial fields of dry beans in Manitoba and Ontario were surveyed to determine the frequency of occurrence of races of the anthracnose fungus. Throughout the study, race 73 was most prevalent in Manitoba and Ontario. However, three anthracnose races not previously reported in Canada also were identified. These three new races and four previously identified anthracnose races were used to screen 52 dry bean cultivars, as well as a mung bean and azuki bean cultivar from Ontario, for their seedling reactions to determine their patterns of race resistance. The dry bean cultivars were classified into a total of 19 resistance spectra based on the pattern of seedling reactions to the seven anthracnose races. The most common resistance spectrum was susceptible to the majority of the anthracnose races and no cultivar was resistant to all of the races. Many bean cultivars produced intermediate anthracnose ratings to races 31 and 105 and tests of 16 dry bean cultivars against those races indicated that all cultivars with intermediate ratings to a specific race were segregating in their seedling reactions and none of the cultivars produced plants with only intermediate anthracnose severity ratings. This study provides new information on the anthracnose reactions of common bean cultivars in Canada, which should be useful for the development of new bean cultivars with durable resistance.

scholarly journals Assessment of physiological races of Exserohilum turcicum isolates from maize in Argentina and Brazil

2021 ◽  
Author(s):  
Barbara Ludwig Navarro ◽  
Lucia Ramos Romero ◽  
María Belén Kistner ◽  
Juliana Iglesias ◽  
Andreas von Tiedemann
Keyword(s):  
Exserohilum Turcicum ◽  
Breeding Programs ◽  
Physiological Races ◽  
Maize Leaves ◽  
Race 1 ◽  
Resistance Reaction ◽  
Qualitative Resistance ◽  
Maize Plants ◽  
Corn Leaf Blight ◽  
Resistant Genotypes

AbstractNorthern corn leaf blight (NCLB) is one of the most important diseases in maize worldwide. It is caused by the fungus Exserohilum turcicum, which exhibits a high genetic variability for virulence, and hence physiological races have been reported. Disease control is based mainly on fungicide application and host resistance. Qualitative resistance has been widely used to control NCLB through the deployment of Ht genes. Known pathogen races are designated according to their virulence to the corresponding Ht gene. Knowledge about of E. turcicum race distribution in maize-producing areas is essential to develop and exploit resistant genotypes. Maize leaves showing distinct elliptical grey-green lesions were collected from maize-producing areas of Argentina and Brazil, and 184 monosporic E. turcicum isolates were obtained. A total of 66 isolates were collected from Argentina during 2015, 2018 and 2019, while 118 isolates from Brazil were collected during 2017, 2018 and 2019. All isolates were screened on maize differential lines containing Ht1, Ht2, Ht3 and Htn1 resistance genes. In greenhouse experiments, inoculated maize plants were evaluated at 14 days after inoculation. Resistance reaction was characterized by chlorosis, and susceptibility was defined by necrosis in the absence of chlorosis. The most frequent race was 0 in both Argentina (83%) and Brazil (65%). Frequencies of race 1 (6% and 24%) and race 23N (5% and 10%) were very low in Argentina and Brazil, respectively. The high frequency of race 0 isolates provides evidence that qualitative resistance based on the tested Ht genes is not being used extensively in Argentina and Brazil to control NCLB. This information may be relevant for growers and breeding programs as the incidence of NCLB is increasing in both countries.

scholarly journals The Grapevine E3 Ubiquitin Ligase VriATL156 Confers Resistance against the Downy Mildew Pathogen Plasmopara viticola

2021 ◽  
Vol 22 (2) ◽  
pp. 940
Author(s):  
Elodie Vandelle ◽  
Pietro Ariani ◽  
Alice Regaiolo ◽  
Davide Danzi ◽  
Arianna Lovato ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Ubiquitin Ligase ◽  
Control Measure ◽  
Durable Resistance ◽  
Genetic Resistance ◽  
E3 Ubiquitin Ligase ◽  
Plasmopara Viticola ◽  
Vitis Vinifera L ◽  
Vitis Species ◽  
Vitis Riparia

Downy mildew, caused by Plasmopara viticola, is one of the most severe diseases of grapevine (Vitis vinifera L.). Genetic resistance is an effective and sustainable control strategy, but major resistance genes (encoding receptors for specific pathogen effectors) introgressed from wild Vitis species, although effective, may be non-durable because the pathogen can evolve to avoid specific recognition. Previous transcriptomic studies in the resistant species Vitis riparia highlighted the activation of signal transduction components during infection. The transfer of such components to V. vinifera might confer less specific and therefore more durable resistance. Here, we describe the generation of transgenic V. vinifera lines constitutively expressing the V. riparia E3 ubiquitin ligase gene VriATL156. Phenotypic and molecular analysis revealed that the transgenic plants were less susceptible to P. viticola than vector-only controls, confirming the role of this E3 ubiquitin ligase in the innate immune response. Two independent transgenic lines were selected for detailed analysis of the resistance phenotype by RNA-Seq and microscopy, revealing the profound reprogramming of transcription to achieve resistance that operates from the earliest stages of pathogen infection. The introduction of VriATL156 into elite grapevine cultivars could therefore provide an effective and sustainable control measure against downy mildew.

scholarly journals Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 404
Author(s):  
Michael R. Yeaman ◽  
Liana C. Chan ◽  
Nagendra N. Mishra ◽  
Arnold S. Bayer
Keyword(s):  
Flow Cytometry ◽  
Host Defense ◽  
Durable Resistance ◽  
Cross Resistance ◽  
Streptococcus Mitis ◽  
Host Defense Peptides ◽  
Strain Pair ◽  
Defense Peptides

Streptococcus mitis-oralis (S. mitis-oralis) infections are increasingly prevalent in specific populations, including neutropenic cancer and endocarditis patients. S. mitis-oralis strains have a propensity to evolve rapid, high-level and durable resistance to daptomycin (DAP-R) in vitro and in vivo, although the mechanism(s) involved remain incompletely defined. We examined mechanisms of DAP-R versus cross-resistance to cationic host defense peptides (HDPs), using an isogenic S. mitis-oralis strain-pair: (i) DAP-susceptible (DAP-S) parental 351-WT (DAP MIC = 0.5 µg/mL), and its (ii) DAP-R variant 351-D10 (DAP MIC > 256 µg/mL). DAP binding was quantified by flow cytometry, in-parallel with temporal (1–4 h) killing by either DAP or comparative prototypic cationic HDPs (hNP-1; LL-37). Multicolor flow cytometry was used to determine kinetic cell responses associated with resistance or susceptibility to these molecules. While overall DAP binding was similar between strains, a significant subpopulation of 351-D10 cells hyper-accumulated DAP (>2–4-fold vs. 351-WT). Further, both DAP and hNP-1 induced cell membrane (CM) hyper-polarization in 351-WT, corresponding to significantly greater temporal DAP-killing (vs. 351-D10). No strain-specific differences in CM permeabilization, lipid turnover or regulated cell death were observed post-exposure to DAP, hNP-1 or LL-37. Thus, the adaptive energetics of the CM appear coupled to the outcomes of interactions of S. mitis-oralis with DAP and selected HDPs. In contrast, altered CM permeabilization, proposed as a major mechanism of action of both DAP and HDPs, did not differentiate DAP-S vs. DAP-R phenotypes in this S. mitis-oralis strain-pair.

Production of Hybrids between Physiological Races of the True Slime Mould Didymium iridis

Nature ◽  
1962 ◽  
Vol 193 (4815) ◽  
pp. 598-599 ◽  
Author(s):  
CONSTANTINE J. ALEXOPOULOS ◽  
GEORGE G. ZABKA
Keyword(s):  
Slime Mould ◽  
Physiological Races ◽  
Didymium Iridis
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