scholarly journals Selection of Host Differentials for Elucidating Pathogenic Variation in Magnaporthe grisea Populations Adapted to Finger Millet (Eleusine coracana)

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1784-1789 ◽  
Author(s):  
Talluri Kiran Babu ◽  
Rajan Sharma ◽  
R. P. Thakur ◽  
Hari D. Upadhyaya ◽  
P. Narayan Reddy ◽  
...  
Keyword(s):  
Andhra Pradesh ◽  
Magnaporthe Grisea ◽  
Finger Millet ◽  
Blast Resistance ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Pathogenic Variation ◽  
Differential Set ◽  
Disease Resistance Breeding ◽  
Selection Of

Blast, caused by Pyricularia grisea (teleomorph: Magnaporthe grisea), is the most devastating disease of finger millet affecting production, utilization, and trade in Africa and Southeast Asia. An attempt was made to select a set of putative host differentials that can be used to determine virulence diversity in finger-millet-infecting populations of M. grisea. Thus, a differential set comprising eight germplasm accessions selected from finger millet core collection (IE 2911, IE 2957, IE 3392, IE 4497, IE 5091, IE 6240, IE 6337, and IE 7079) and a resistant (‘GPU 28’) and a susceptible (‘VR 708’) variety was developed. This differential set was used to study pathogenic variation in 25 isolates of M. grisea collected from Karnataka, Telangana, and Andhra Pradesh states in India. Based on the reaction (virulent = score ≥4 and avirulent = score ≤3 on a 1-to-9 scale) on host differentials, nine pathotypes were identified among 25 M. grisea isolates. Pathotype 9, represented by isolate Pg23 from Vizianagaram, was the most virulent because it could infect all of the host differentials except GPU 28. This study will be helpful in devising strategies for monitoring virulence change in M. grisea populations, and for identification of blast resistance in finger millet for use in disease resistance breeding programs.

scholarly journals Exploiting Genetic Diversity for Blast Disease Resistance Sources in Finger Millet (Eleusine coracana)

2019 ◽  
Vol 20 (3) ◽  
pp. 180-186
Author(s):  
Eric O. Manyasa ◽  
Pangirayi Tongoona ◽  
Paul Shanahan ◽  
Stephen Githiri ◽  
Henry Ojulong ◽  
...  
Keyword(s):  
East Africa ◽  
Magnaporthe Grisea ◽  
Finger Millet ◽  
Smallholder Farmers ◽  
Blast Resistance ◽  
Resistance Breeding ◽  
Blast Disease ◽  
Direct Production ◽  
Ecological Zones ◽  
Grain Color

Finger millet blast, caused by Magnaporthe grisea, is the most important disease of finger millet in East Africa. Diseased plants are significantly less productive, and most cultivars grown by farmers are susceptible to the disease. Fungicide application is an option for disease management; however, smallholder farmers cannot afford the cost. Host plant resistance is therefore the most viable option for managing the disease. Eighty-one finger millet germplasm accessions from East Africa were evaluated for resistance to blast disease, in natural and inoculated trials. Three accessions (G18, G43, and G67) were identified as resistant to all the three progressive stages of blast: leaf, neck, and panicle. However, one (G3) and four (G15, G16, G60, and G70) accessions were only resistant to leaf and neck blast, respectively. Two resistant (G39 and G43) and 12 moderately resistant (G3, G7, G11, G20, G23, G27, G31, G33, G36, G66, G74, and G81) accessions to blast attained grain yields >2.0 t/ha. These accessions varied in time to maturity, plant height, and grain color, which will enable farmers to select accessions appropriate to their target agro-ecological zones and desired end uses. East African finger millet germplasm has high potential as a source of blast-resistant accessions that could be evaluated for direct production and/or for blast-resistance breeding.

scholarly journals Natural Variation at the Pi-ta Rice Blast Resistance Locus

2003 ◽  
Vol 93 (11) ◽  
pp. 1452-1459 ◽  
Author(s):  
Yulin Jia ◽  
Gregory T. Bryan ◽  
Leonard Farrall ◽  
Barbara Valent
Keyword(s):  
Positional Cloning ◽  
Magnaporthe Grisea ◽  
Blast Resistance ◽  
El Paso ◽  
Avirulence Gene ◽  
Resistance Locus ◽  
Japonica Rice ◽  
Breeding Programs ◽  
Rice Blast Resistance ◽  
Intron Region

The resistance gene Pi-ta protects rice crops against the fungal pathogen Magnaporthe grisea expressing the avirulence gene AVR-Pita in a gene-for-gene manner. Pi-ta, originally introgressed into japonica rice from indica origin, was previously isolated by positional cloning. In this study, we report the nucleotide sequence of a 5,113-base pair region containing a japonica susceptibility pi-ta allele, which has overall 99.6% nucleotide identity to the indica Pi-ta allele conferring resistance. The intron region shows the levels of sequence diversity that typically differentiate genes from indica and japonica rices, but the other gene regions show less diversity. Sequences of the Pi-ta allele from resistant cultivars Katy and Drew from the southern United States are identical to the resistance Pi-ta sequence. Sequences from susceptible cultivars El Paso 144 and Cica 9 from Latin America define a third susceptibility haplotype. This brings the total number of Pi-ta haplotypes identified to four, including the resistance allele and three susceptibility alleles. The Pi-ta locus shows low levels of DNA polymorphism compared with other analyzed R genes. Understanding the natural diversity at the Pi-ta locus is important for designing specific markers for incorporation of this R gene into rice-breeding programs.

scholarly journals Cross-Compatibility and Distribution of Mating Type Alleles of the Rice Blast Fungus Magnaporthe grisea in India

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 700-704 ◽  
Author(s):  
B. V. Dayakar ◽  
N. N. Narayanan ◽  
S. S. Gnanamanickam
Keyword(s):  
Mating Type ◽  
Andhra Pradesh ◽  
Magnaporthe Grisea ◽  
Finger Millet ◽  
Fragment Length Polymorphism ◽  
Rice Blast Fungus ◽  
Mating Types ◽  
Andaman Islands ◽  
Cross Compatibility ◽  
Pathogenicity Tests

Two hundred twenty-seven isolates of Magnaporthe grisea isolated from blast-infected rice tissues from different states of India were tested with MAT1-1 and MAT1-2 fertile standard testers to determine their mating type. Of the 227 monoconidial isolates, 90 (39.6%) were fertile and 137 (60.4%) were infertile and did not produce perithecia when mated with any of the four testers. In the states of Meghalaya and Himachal Pradesh, both mating types were found. In the states of Andaman Islands, Andhra Pradesh, Karnataka, Haryana, and Punjab, only mating type MAT1-1 was identified. In states where MAT1-2 occurred, its frequency was low. Among the 90 fertile isolates, 40 (44.4%) produced perithecia, asci, and ascospores, and 11 of those isolates produced perithecia, asci, and ascospores with both MAT1-2 testers, KA-9 of finger millet, and GUY11 of rice origin. However, when monoconidial isolates were mated among themselves, isolates from the same field produced only barren perithecia. Pathogenicity tests of the ascospore progeny derived from crosses of field isolates and host-specific testers revealed that none of the ascospore progeny were as virulent as the parents, despite showing compatible reactions with both rice and finger millet cultivars. These results indicate that recombinant progeny may be at a selective disadvantage despite having an increased host range. This is the first report of the occurrence of high levels of fertility (24 to 52%) in rice isolates of M. grisea in different states of India. In a Southern blot analysis, 58% of 74 isolates were identified as MAT1-1 and 41% as MAT1-2. In this population, 23 Magnaporthe grisea repeat (MGR)-restriction fragment length polymorphism groups or lineages were identified. In terms of lineage composition, the 18 isolates from Meghalaya showed maximal diversity with nine lineages.

Problems Encountered with the Selection of Cucumber Mosaic Virus (CMV) Isolates for Resistance Breeding Programs

2011 ◽  
Vol 159 (9) ◽  
pp. 621-629 ◽  
Author(s):  
Deyong Zhang ◽  
Xinqiu Tan ◽  
Peter Willingmann ◽  
Guenter Adam ◽  
Cornelia Heinze
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Selection Of

scholarly journals Effectors as Tools in Disease Resistance Breeding Against Biotrophic, Hemibiotrophic, and Necrotrophic Plant Pathogens

2014 ◽  
Vol 27 (3) ◽  
pp. 196-206 ◽  
Author(s):  
Vivianne G. A. A. Vleeshouwers ◽  
Richard P. Oliver
Keyword(s):  
Fungicide Resistance ◽  
Plant Pathogens ◽  
Functional Characterization ◽  
Resistance Breeding ◽  
World Population ◽  
Breeding Programs ◽  
Genome Wide ◽  
Disease Resistance Breeding ◽  
Pathogen Populations ◽  
New Strategies

One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. “Effectoromics” has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems.

scholarly journals Selection of powdery mildew resistant and susceptible grapevine genotypes with molecular markers

2007 ◽  
pp. 100-104
Author(s):  
Stella Molnár ◽  
Zsuzsanna Galbács ◽  
Gábor Halász ◽  
Sarolta Hoffmann ◽  
Anikó Veres ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Powdery Mildew ◽  
Marker Assisted Selection ◽  
Powdery Mildew Resistance ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Pcr Rflp ◽  
Muscadinia Rotundifolia ◽  
Selection Of ◽  
Grape Breeding

Incorporation of competitive quality and resistance against the most important fungal diseases (powdery and downy mildew) in a cultivar is one of the most important aims of grapevine breeding. In the 20th century, the most advanced results in grapevine resistance breeding were achieved by French researchers. They used resistant cultivars in more than 30% of their growing areas. In these varieties, North American wild Vitisspecies were the resistance gene sources. The discovery of immunity-like resistance of Muscadinia rotundifolia opened new perspectives in resistance breeding. M. rotundifolia harbours a dominant powdery mildew gene, providing resistance in highquality cultivars after back-crosses with V. vinifera varieties. M. rotundifolia has been involved in the Hungarian grape breeding programs since 1996, thanks to a French-Hungarian variety exchange. In addition to traditional selection methods, application of MAS (Marker Assisted Selection) based on various types ofmolecular markers, can provide additional tools for these efforts. Run1 locus, responsible for powdery mildew resistance, was identified in Muscadinia rotundifolia. Molecular markers closely linked to this locus are very significant in screening progenies deriving from M. rotundifolia and V. vinifera crosses, making possible the discrimination between resistant and susceptible genotypes at DNA level. In our analyses BC5 progeny of {(M. rotundifola×V. vinifera) BC4}×Cardinal (V. vinifera) tested for powdery symptoms were analysed with PCR-RFLP (GLP1- 12P1P3) and microsatellite markers (VMC4f3.1, VMC8g9). Our results proved the applicability of the linked markers and reliability of marker assisted selection.

scholarly journals Evaluation of the response of Turkey strains to Salmonella and Newcastle vaccines

2021 ◽  
pp. 1-9
Author(s):  
Ekei Victor Ikpeme
Keyword(s):  
Immune Response ◽  
Antibody Titre ◽  
Research Work ◽  
Haemagglutination Inhibition ◽  
Resistance Breeding ◽  
Laboratory Assessment ◽  
Blood Samples ◽  
Black And White ◽  
Disease Resistance Breeding ◽  
Selection Of

This research work was carried out to evaluate the immune response of 3 turkey strains to salmonella and Newcastle vaccines measured via antibody titre. The study deployed a total of 120 poults (40 black, 40 white and 40 lavender) strains. To ascertain the initial antibody titre of all the birds, blood samples were obtained from their wing veins immediately after acclimatization for salmonella and Newcastle antibody titre.  The test for salmonella and Newcastle antibody titre responses of the birds were performed using widal and haemagglutination inhibition (HI), respectively. The birds were divided into two broad groups tagged as A and B, which represented Salmonella and Newcastle vaccines, respectively. Each group had 3 sub-groups denoting the 3 strains of turkey used for the study. After vaccination, blood samples were collected from all the birds at 3 and 5 days for laboratory assessment of antibody titre response. The results showed that there was significant increase (p<0.05) in the antibody titre response of all the turkey strains after vaccination. Results obtained on the time of exposure of the birds to vaccine revealed that higher antibody titre values were obtained from the black and white turkey strains at 3 days than at 5 days after administration of Newcastle vaccine, except in the lavender strain, which had higher titre value at 5 days after Newcastle vaccination. Following administration of salmonella vaccine, black and lavender strains had statistically higher antibody titre response (2.03 and 2.10 mean loge widal, respectively) than white strain (1.86 mean loge widal). Similarly, the black strain also had higher antibody titre value when Newcastle vaccine was administered (2.35 mean loge HI) followed by lavender (1.99 mean loge HI) and white strain (1.71 mean loge HI). Black strains showed more antibody titre response and by implication, stronger immunity to Salmonella and Newcastle vaccines. More importantly, the differential response of the 3 turkey strains to vaccine could give turkey breeders the choice of selection of turkey breeds for disease resistance breeding.

scholarly journals Pathogenic Variation of Cladosporium caryigenum Isolates and Corresponding Differential Resistance in Pecan

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 553-557 ◽  
Author(s):  
Patrick J. Conner ◽  
Katherine L. Stevenson
Keyword(s):  
Plant Cell Wall ◽  
Differential Resistance ◽  
Carya Illinoinensis ◽  
Causal Organism ◽  
Breeding Programs ◽  
Large Pool ◽  
Pathogenic Variation ◽  
Virulence Pattern ◽  
Cladosporium Caryigenum ◽  
Selection Of

To facilitate the breeding of scab-resistant pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars, more information is needed about the pathogenic variation of the causal organism, Cladosporium caryigenum (Ell. et Lang.) Gottwald (1982). This study examined the virulence patterns resulting from the field inoculations of 19 pecan cultivars with 12 monoconidial isolates from 8 pecan cultivars at 7 locations. The virulence pattern was different for each of the fungal isolates. Each isolate was virulent on some cultivars and avirulent on others. Most isolates were most virulent on the cultivar of their origin and one or a few other cultivars. Several cultivars were resistant to most of the tested isolates. The results indicate a large pool of differential and ephemeral resistance to scab resides in the pecan germplasm. Microscopic examination of developing lesions suggests that resistance is mediated by the speed of plant cell wall modifications that limit the growth of subcuticular hyphae. This information will be useful in the selection of cultivars with functionally different resistance genes for use in designing cultivar mixtures or in breeding programs.

scholarly journals Deciphering Genotype-By-Environment Interaction for Target Environmental Delineation and Identification of Stable Resistant Sources Against Foliar Blast Disease of Pearl Millet

2021 ◽  
Vol 12 ◽  
Author(s):  
S. Mukesh Sankar ◽  
S. P. Singh ◽  
G. Prakash ◽  
C. Tara Satyavathi ◽  
S. L. Soumya ◽  
...  
Keyword(s):  
Pearl Millet ◽  
Magnaporthe Grisea ◽  
Resistance Breeding ◽  
Genotype By Environment Interaction ◽  
Blast Disease ◽  
Environment Interaction ◽  
Breeding Programs ◽  
Genotype By Environment ◽  
Desirability Index ◽  
Resistant Genotypes

Once thought to be a minor disease, foliar blast disease of pearl millet, caused by Magnaporthe grisea, has recently emerged as an important biotic constraint for pearl millet production in India. The presence of a wider host range as well as high pathogenic heterogeneity complicates host–pathogen dynamics. Furthermore, environmental factors play a significant role in exacerbating the disease severity. An attempt was made to unravel the genotype-by-environment interactions for identification and validation of stable resistant genotypes against foliar blast disease through multi-environment testing. A diversity panel consisting of 250 accessions collected from over 20 different countries was screened under natural epiphytotic conditions in five environments. A total of 43 resistant genotypes were found to have high and stable resistance. Interestingly, most of the resistant lines were late maturing. Combined ANOVA of these 250 genotypes exhibited significant genotype-by-environment interaction and indicated the involvement of crossover interaction with a consistent genotypic response. This justifies the necessity of multi-year and multi-location testing. The first two principal components (PCs) accounted for 44.85 and 29.22% of the total variance in the environment-centered blast scoring results. Heritability-adjusted genotype plus genotype × environment interaction (HA-GGE) biplot aptly identified “IP 11353” and “IP 22423, IP 7910 and IP 7941” as “ideal” and “desirable” genotypes, respectively, having stable resistance and genetic buffering capacity against this disease. Bootstrapping at a 95% confidence interval validated the recommendations of genotypes. Therefore, these genotypes can be used in future resistance breeding programs in pearl millet. Mega-environment delineation and desirability index suggested Jaipur as the ideal environment for precise testing of material against the disease and will increase proper resource optimization in future breeding programs. Information obtained in current study will be further used for genome-wide association mapping of foliar blast disease in pearl millet.

Sign in / Sign up

Export Citation Format

Share Document