scholarly journals Multiple Mechanisms Drive the Evolutionary Adaptation of Phytophthora infestans Effector Avr1 to Host Resistance

2021 ◽  
Vol 7 (10) ◽  
pp. 789
Author(s):  
Lin-Lin Shen ◽  
Abdul Waheed ◽  
Yan-Ping Wang ◽  
Oswald Nkurikiyimfura ◽  
Zong-Hua Wang ◽  
...  
Keyword(s):  
Disease Management ◽  
Phytophthora Infestans ◽  
Host Resistance ◽  
Population Genetic ◽  
Base Substitution ◽  
Intragenic Recombination ◽  
Diversifying Selection ◽  
Effector Gene ◽  
Small Proteins ◽  
Effector Genes

Effectors, a group of small proteins secreted by pathogens, play a central role in antagonistic interactions between plant hosts and pathogens. The evolution of effector genes threatens plant disease management and sustainable food production, but population genetic analyses to understand evolutionary mechanisms of effector genes are limited compared to molecular and functional studies. Here we investigated the evolution of the Avr1 effector gene from 111 Phytophthora infestans isolates collected from six areas covering three potato cropping regions in China using a population genetic approach. High genetic variation of the effector gene resulted from diverse mechanisms including base substitution, pre-termination, intragenic recombination and diversifying selection. Nearly 80% of the 111 sequences had a point mutation in the 512th nucleotide (T512G), which generated a pre-termination stop codon truncating 38 amino acids in the C-terminal, suggesting that the C-terminal may not be essential to ecological and biological functions of P. infestans. A significant correlation between the frequency of Avr1 sequences with the pre-termination and annual mean temperature in the collection sites suggests that thermal heterogeneity might be one of contributors to the diversifying selection, although biological and biochemical mechanisms of the likely thermal adaptation are not known currently. Our results highlight the risk of rapid adaptation of P. infestans and possibly other pathogens as well to host resistance, and the application of eco-evolutionary principles is necessary for sustainable disease management in agricultural ecosystems.

scholarly journals Effector Avr4 in Phytophthora infestans Escapes Host Immunity Mainly Through Early Termination

2021 ◽  
Vol 12 ◽  
Author(s):  
Abdul Waheed ◽  
Yan-Ping Wang ◽  
Oswald Nkurikiyimfura ◽  
Wen-Yang Li ◽  
Shi-Ting Liu ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Air Temperature ◽  
Climatic Factors ◽  
Isolation By Distance ◽  
Plant Diseases ◽  
Nucleotide Position ◽  
Effector Gene ◽  
Effector Genes ◽  
Base Pair Deletion ◽  
Mutation Mechanisms

Effector genes play critical roles in the antagonistic interactions between plants and pathogens. However, knowledge of mutation mechanisms and evolutionary processes in effector genes and the contribution of climatic factors to the evolution of effector genes are fragmented but important in sustainable management of plant diseases and securing food supply under changing climates. Here, we used a population genetic approach to explore the evolution of the Avr4 gene in Phytophthora infestans, the causal agent of potato blight. We found that the Avr4 gene exhibited a high genetic diversity generated by point mutation and sequence deletion. Frameshifts caused by a single base-pair deletion at the 194th nucleotide position generate two stop codons, truncating almost the entire C-terminal, which is important for effector function and R4 recognition in all sequences. The effector is under natural selection for adaptation supported by comparative analyses of population differentiation (FST) and isolation-by-distance between Avr4 sequences and simple sequence repeat marker loci. Furthermore, we found that local air temperature was positively associated with pairwise FST in the Avr4 sequences. These results suggest that the evolution of the effector gene is influenced by local air temperature, and the C-terminal truncation is one of the main mutation mechanisms in the P. infestans effector gene to circumvent the immune response of potato plants. The implication of these results to agricultural and natural sustainability in future climate conditions is discussed.

scholarly journals Number of Candidate Effector Genes in Accessory Genomes Differentiates Pathogenic From Endophytic Fusarium oxysporum Strains

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria E. Constantin ◽  
Like Fokkens ◽  
Mara de Sain ◽  
Frank L. W. Takken ◽  
Martijn Rep
Keyword(s):  
Fusarium Oxysporum ◽  
Plant Species ◽  
Genetic Basis ◽  
Molecular Level ◽  
Similar Amount ◽  
Tomato Plants ◽  
Grass Roots ◽  
Effector Gene ◽  
Effector Genes ◽  
Potential Pathogen

The fungus Fusarium oxysporum (Fo) is widely known for causing wilt disease in over 100 different plant species. Endophytic interactions of Fo with plants are much more common, and strains pathogenic on one plant species can even be beneficial endophytes on another species. However, endophytic and beneficial interactions have been much less investigated at the molecular level, and the genetic basis that underlies endophytic versus pathogenic behavior is unknown. To investigate this, 44 Fo strains from non-cultivated Australian soils, grass roots from Spain, and tomato stems from United States were characterized genotypically by whole genome sequencing, and phenotypically by examining their ability to symptomlessly colonize tomato plants and to confer resistance against Fusarium Wilt. Comparison of the genomes of the validated endophytic Fo strains with those of 102 pathogenic strains revealed that both groups have similar genomes sizes, with similar amount of accessory DNA. However, although endophytic strains can harbor homologs of known effector genes, they have typically fewer effector gene candidates and associated non-autonomous transposons (mimps) than pathogenic strains. A pathogenic ‘lifestyle’ is associated with extended effector gene catalogs and a set of “host specific” effectors. No candidate effector genes unique to endophytic strains isolated from the same plant species were found, implying little or no host-specific adaptation. As plant-beneficial interactions were observed to be common for the tested Fo isolates, the propensity for endophytism and the ability to confer biocontrol appears to be a predominant feature of this organism. These findings allow prediction of the lifestyle of a Fo strain based on its genome sequence as a potential pathogen or as a harmless or even beneficial endophyte by determining its effectorome and mimp number.

Diversity of Avr-vnt1 and AvrSmira1 effector genes in Polish and Norwegian populations of Phytophthora infestans

2018 ◽  
Vol 67 (8) ◽  
pp. 1792-1802 ◽  
Author(s):  
E. Stefańczyk ◽  
M. Brylińska ◽  
M. B. Brurberg ◽  
R. Naerstad ◽  
A. Elameen ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Effector Genes

The Effect of a Dominant Phytophthora infestans Genotype (13_A2) in Great Britain on Host Resistance to Foliar Late Blight in Commercial Potato Cultivars

2012 ◽  
Vol 55 (2) ◽  
pp. 125-134 ◽  
Author(s):  
A. K. Lees ◽  
J. A. Stewart ◽  
J. S. Lynott ◽  
S. F. Carnegie ◽  
H. Campbell ◽  
...  
Keyword(s):  
Great Britain ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Host Resistance ◽  
Potato Cultivars ◽  
Commercial Potato

scholarly journals Co-evolutionary interactions between host resistance and pathogen effector genes in flax rust disease

2010 ◽  
Vol 12 (1) ◽  
pp. 93-102 ◽  
Author(s):  
MICHAEL RAVENSDALE ◽  
ADNANE NEMRI ◽  
PETER H. THRALL ◽  
JEFFREY G. ELLIS ◽  
PETER N. DODDS
Keyword(s):  
Host Resistance ◽  
Rust Disease ◽  
Effector Genes ◽  
Pathogen Effector

scholarly journals Evaluating Host Resistance to Limit Colletotrichum coccodes on Onion

HortScience ◽  
2018 ◽  
Vol 53 (7) ◽  
pp. 916-919
Author(s):  
Lina M. Rodríguez-Salamanca ◽  
Mary K. Hausbeck
Keyword(s):  
Disease Management ◽  
Disease Severity ◽  
Allium Cepa ◽  
Host Resistance ◽  
Management Strategy ◽  
Field Studies ◽  
Colletotrichum Coccodes ◽  
Integrated Disease Management ◽  
Disease Management Strategy ◽  
Brown Center

Leaf and neck anthracnose is incited by Colletotrichum coccodes (Wallr.) Hughes, a new foliar disease of onion (Allium cepa L.) in Michigan that has been observed in the state since 2010. Symptoms include elliptical lesions on the leaves, necks, or both that appear bleached with a pale salmon to dark brown center. To develop an effective integrated disease management strategy, field studies were conducted in 2011 and 2012 to evaluate 16 commercial onion cultivars for their susceptibility to the pathogen. The incidence and severity of anthracnose were evaluated weekly following inoculation. Onion cultivars differed significantly in disease severity and incidence; differences between years were also observed. ‘Hendrix’ had the lowest disease severity, whereas ‘Highlander’ and ‘Candy’ exhibited severe onion leaf and neck anthracnose symptoms. Using less susceptible onion cultivars combined with effective fungicides against C. coccodes may limit crop losses for Michigan growers.

scholarly journals Population Genetic Structure of Phytophthora infestans in Ecuador

1997 ◽  
Vol 87 (4) ◽  
pp. 375-380 ◽  
Author(s):  
Gregory A. Forbes ◽  
Ximena C. Escobar ◽  
Catalina C. Ayala ◽  
Jorge Revelo ◽  
Maria E. Ordoñez ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Nuclear Dna ◽  
Dna Fingerprint ◽  
Clonal Lineage ◽  
Metalaxyl Sensitivity ◽  
Neutral Markers

The population genetic structure of Phytophthora infestans in Ecuador was assessed from 101 isolates collected from 1990 to 1992 and 111 isolates collected in 1993. All isolates were analyzed for mating type and allozyme genotype. Both samples were dominated (>95%) by a clonal lineage (EC-1) defined from neutral markers: 90/100 genotype for glucose-6-phosphate isomerase, 96/100 genotype for peptidase, A1 mating type, and a previously unreported nuclear DNA fingerprint. The remaining isolates belonged to the US-1 clonal lineage, which has a worldwide distribution. Isolates in the 1993 sample were analyzed for virulence and metalaxyl sensitivity. All representatives of EC-1 had complex patho-types, with three pathotypes representing >60% of the collection. There was variation for metalaxyl sensitivity. There was no evidence for geographical substructuring on the basis of neutral markers, but there was evidence for limited substructuring based on metalaxyl sensitivity and specific virulence. We hypothesize that EC-1 has been recently introduced to Ecuador.

Sign in / Sign up

Export Citation Format

Share Document