scholarly journals Comparative analysis of late blight resistance R genes and their coding proteins in some potato genotypes

2021 ◽  
Author(s):  
Heba Amin Mahfouze ◽  
Osama Ezzat El-Sayed
Keyword(s):  
Amino Acid ◽  
Late Blight ◽  
Base Pair ◽  
Durable Resistance ◽  
Late Blight Resistance ◽  
Nucleotide Sequences ◽  
The Other ◽  
Solid Base ◽  
R Genes ◽  
Sequence Alignments

Late blight (LB) disease can cause potato yield losses in both Egypt and the world. Therefore, the structural analysis of resistance (R) genes responsible for LB resistance will help in understanding their functions. This work aimed to identify the variations between the dominant and recessive alleles of two genes, R3a and R8 at the nucleotide and amino acid levels in five potato genotypes. Two genes of R3a and R8 representing the broad-spectrum LB resistance were amplified by specific primers, which gave one amplicon of 194 and 220 bp of each gene, respectively. Two fragments were sequenced after purification using an ABI 3730xl System DNA Sequencer. The DNA sequence alignments of two genes, R3a and R8, were determined among five selected potato genotypes. The percentage of genetic similarity of the nucleotide sequences of the R3a and R8 genes ranged between (82–83%) and (86–87%), respectively, in comparison to the reference sequences in the nucleotide BLAST. We report on the existence of positional differences in the nucleotide sequences, and base-pair substitutions of two fragments, resulting in amino acid changes between the resistant and susceptible potato genotypes. On the other hand, the highest total number of base-pair substitutions was recorded as 16 in the recessive allele r8 of the varieties Bellini and Cara. However, the lowest number was recorded as four in the dominant allele R3a of the variety Cara. The dendrograms of the five potato genotypes were made up of phylogenetically different clusters, separate from all the other named potato accessions of the two genes. The results of this study will create a solid base for the further understanding of the mechanism of plant-pathogen interactions and supply a theoretical reference for durable resistance to late blight diseases in the potato.

scholarly journals Mutations introduced in susceptibility genes through CRISPR/Cas9 genome editing confer increased late blight resistance in potatoes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nam Phuong Kieu ◽  
Marit Lenman ◽  
Eu Sheng Wang ◽  
Bent Larsen Petersen ◽  
Erik Andreasson
Keyword(s):  
Late Blight ◽  
Late Blight Resistance ◽  
Susceptibility Genes ◽  
Blight Resistance ◽  
R Genes ◽  
Guide Rnas ◽  
Knockout Mutants ◽  
Growth Phenotype ◽  
Allelic Deletion ◽  
S Genes

AbstractThe use of pathogen-resistant cultivars is expected to increase yield and decrease fungicide use in agriculture. However, in potato breeding, increased resistance obtained via resistance genes (R-genes) is hampered because R-gene(s) are often specific for a pathogen race and can be quickly overcome by the evolution of the pathogen. In parallel, susceptibility genes (S-genes) are important for pathogenesis, and loss of S-gene function confers increased resistance in several plants, such as rice, wheat, citrus and tomatoes. In this article, we present the mutation and screening of seven putative S-genes in potatoes, including two DMR6 potato homologues. Using a CRISPR/Cas9 system, which conferred co-expression of two guide RNAs, tetra-allelic deletion mutants were generated and resistance against late blight was assayed in the plants. Functional knockouts of StDND1, StCHL1, and DMG400000582 (StDMR6-1) generated potatoes with increased resistance against late blight. Plants mutated in StDND1 showed pleiotropic effects, whereas StDMR6-1 and StCHL1 mutated plants did not exhibit any growth phenotype, making them good candidates for further agricultural studies. Additionally, we showed that DMG401026923 (here denoted StDMR6-2) knockout mutants did not demonstrate any increased late blight resistance, but exhibited a growth phenotype, indicating that StDMR6-1 and StDMR6-2 have different functions. To the best of our knowledge, this is the first report on the mutation and screening of putative S-genes in potatoes, including two DMR6 potato homologues.

scholarly journals Genetic Diversity in Diploid and Tetraploid Late Blight Resistant Potato Germplasm

HortScience ◽  
2002 ◽  
Vol 37 (1) ◽  
pp. 178-183 ◽  
Author(s):  
Dilson A. Bisognin ◽  
David S. Douches
Keyword(s):  
Genetic Diversity ◽  
Late Blight ◽  
Durable Resistance ◽  
Late Blight Resistance ◽  
Blight Resistance ◽  
Pair Group ◽  
Potato Germplasm ◽  
Genetic Base ◽  
The Matrix ◽  
Isozyme Loci

An understanding of the genetic relationship within potato germplasm is important to establish a broad genetic base for breeding purposes. The objective of this study was to assess the genetic diversity of potato (Solanum tuberosum subsp. tuberosum Hawkes) germplasm that can be used in the development of cultivars with resistance to late blight caused by Phytophthora infestans (Mont.) de Bary. Thirty-three diploid and 27 tetraploid late blight resistant potato clones were evaluated for their genetic diversity based on 11 isozyme loci and nine microsatellites. A total of 35 allozymes and 42 polymorphic microsatellite fragments was scored for presence or absence. The germplasm was clustered based on the matrix of genetic similarities and the unweighted pair group means analysis of the isozyme and microsatellite data, which were used to construct a dendrogram using NTSYS-pc version 1.7. Twenty-three allozymes and DNA fragments were unique to the wild species. The diploid Solanum species S. berthaultii Hawkes and S. microdontum Bitter formed two distinct phenetic groups. Within S. microdontum, three subgroups were observed. The tetraploid germplasm formed another group, with S. sucrense Hawkes in one subgroup and the cultivated potato and Russian hybrids in another subgroup. Based upon the genetic diversity and the level of late blight resistance, S. microdontum and S. sucrense offer the best choice for strong late blight resistance from genetically diverse sources. This potato germplasm with reported late blight resistance should be introgressed into the potato gene pool to broaden the genetic base to achieve stronger and more durable resistance.

scholarly journals Pathogenic Fitness of Oosporic Progeny Isolates of Phytophthora infestans on Late-Blight-Resistant Tomato Lines

Plant Disease ◽  
2009 ◽  
Vol 93 (9) ◽  
pp. 947-953 ◽  
Author(s):  
Shiri Klarfeld ◽  
Avia (Evgenia) Rubin ◽  
Yigal Cohen
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Field Isolate ◽  
Late Blight Resistance ◽  
The Other ◽  
Host Genotype ◽  
Unit Leaf ◽  
Tomato Genotype ◽  
Different Levels ◽  
Tomato Genotypes

Four A1 field isolates and one A2 field isolate of Phytophthora infestans were crossed to produce oospores in tomato leaves. The oospores were extracted and mixed with perlite and water, and healthy tomato leaves were used as bait for oospore-progeny infection. Twenty-nine lesions were obtained from the four crosses and 283 single-sporangium isolates were recovered and tested on four tomato differential lines carrying different major genes (Ph-0, Ph-1, Ph-2, and 3707) for late blight resistance. The pathogenic fitness (number of sporangia per unit leaf area) of parental and progeny isolates was strongly dependent on the host genotype; it decreased in the order Ph-0 > Ph-1 > Ph-2 > 3707. The A2 parent had a higher pathogenic fitness than the A1 parents on Ph-0 and Ph-1 but similar, lower fitness on Ph-2. Different levels of pathogenic fitness were observed across all isolates on Ph-0, although Ph-0 lacks resistance genes. Pathogenic fitness on one tomato genotype was not related to the pathogenic fitness on the other tomato genotypes. Some isolates exhibited reduced pathogenic fitness relative to the respective A1 parent, whereas others demonstrated a higher pathogenic fitness compared with the A2 parent. The tomato genotype Solanum pimpinellifolium L3707/5 was resistant to all five parental isolates of P. infestans. However, 37 of the 283 progeny isolates from 11 different lesions had compatible reactions with this line, producing up to 31 × 103 sporangia/cm2. Overall, reduced fitness was more frequent among the progeny isolates than increased fitness.

scholarly journals Expression of the Potato Late Blight Resistance Gene Rpi-phu1 and Phytophthora infestans Effectors in the Compatible and Incompatible Interactions in Potato

2017 ◽  
Vol 107 (6) ◽  
pp. 740-748 ◽  
Author(s):  
Emil Stefańczyk ◽  
Sylwester Sobkowiak ◽  
Marta Brylińska ◽  
Jadwiga Śliwka
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Expression Patterns ◽  
Late Blight Resistance ◽  
Blight Resistance ◽  
Transcriptional Level ◽  
R Genes ◽  
Transcript Accumulation ◽  
Breeding Lines ◽  
Additional Resistance

This study describes late blight resistance of potato breeding lines resulting from crosses between cultivar ‘Sárpo Mira’ and Rpi-phu1 gene donors. The progeny is investigated for the presence of Rpi-Smira1 and Rpi-phu1 resistance (R) genes. Interestingly, in detached-leaflet tests, plants with both R genes withstood the infection of the Phytophthora infestans isolate virulent to each gene separately, due to either interaction of these genes or the presence of additional resistance loci. The interaction was studied further in three chosen breeding lines on the transcriptional level. The Rpi-phu1 expression, measured over 5 days, revealed different patterns depending on the outcome of the interaction with P. infestans: it increased in infected plants whereas it remained low and stable when infection was unsuccessful. The expression patterns of P. infestans effectors Avr-vnt1, AvrSmira1, and Avr8, recognized by the Rpi-phu1, Rpi-Smira1, and Rpi-Smira2 genes, respectively, were evaluated in the same experimental setup. This is the first report that the Avr-vnt1 effector expression is not switched off permanently in virulent isolates to avoid recognition by an R protein but can reappear in a postbiotrophic phase and is present constantly when infecting plants without the corresponding R gene. Both a plant and a pathogen can react to the other interacting side by changing the transcript accumulation of R genes or effectors.

scholarly journals Resistance to Phytophthora Infestans in Three Solanum Nigrum F3 Families

2014 ◽  
Vol 66 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Jadwiga Śliwka ◽  
Iga Tomczyńska ◽  
Marcin Chmielarz ◽  
Emil Stefańczyk ◽  
Renata Lebecka ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Single Gene ◽  
Late Blight Resistance ◽  
Solanum Nigrum ◽  
The Other ◽  
Blight Resistance ◽  
Inheritance Of Resistance ◽  
Detached Leaf ◽  
Complex Inheritance

AbstractSolanum nigrumis a self-pollinating, hexaploid weed and one of a fewSolanaceaespecies native to Europe. It used to be described as a non-host forPhytophthora infestans. However, now it is known that, like its distant relatives: potato (Solanum tuberosumL.) and tomato (Solanum lycopersicumL.),S. nigrumcan suffer from potato late blight caused by this pathogen. Both susceptible and resistantS. nigrumgenotypes have been previously identified and inheritance of resistance originating from one accession has been described based on population of F2plants and 15 F3lines. The goal of this study was to evaluate resistance of three families of F3lines, originating from crosses between a susceptible and three different resistantS. nigrumaccessions followed by two self-pollinations. Parental accessions were tested for the spectrum of late blight resistance against 48P. infestansisolates. The three families consisted of 106, 96 and 115 F3lines, respectively, and from each line 20 plants were tested for resistance toP. infestans. Laboratory detached leaf assays were performed in two dates and two replications of three leaves each. Segregation of the trait within the line allowed us to distinguish hetero- and homozygous lines. In one F3family, the ratio of resistant homozygotes: heterozygotes: susceptible homozygotes was 1:2:1, indicating that a single gene is most likely underlying the late blight resistance in this case. In the other two, observed segregations of the trait significantly deviated from this model suggesting more complex inheritance patterns.

scholarly journals Fine mapping of the Ph-2 gene conferring resistance to late blight (Phytophthora infestans) in tomato

Plant Disease ◽  
2020 ◽  
Author(s):  
Xiaona Zhi ◽  
Jinshuai Shu ◽  
Zheng Zheng ◽  
Tao Li ◽  
Xiaorong Sun ◽  
...  
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Fine Mapping ◽  
Molecular Breeding ◽  
Late Blight Resistance ◽  
Genomic Region ◽  
R Genes ◽  
F2 Population ◽  
New Varieties ◽  
Tomato Disease

Late blight is a devastating tomato disease. Breeding new varieties with multiple resistance (R) genes is highly effective for preventing late blight. The Ph-2 gene mediates resistance to Phytophthora infestans race T1 in tomato. In this study, we used an F2 population derived from a cross between Solanum lycopersicum Moboline (resistant) and LA3988 (susceptible) for the fine mapping of Ph-2. Two flanking markers, CAPS-1 and CC-Ase, mapped Ph-2 to a 141-kb genomic region containing 21 projected genes, five of which were identified as putative R genes. The Solyc10g085460 coding sequence varied significantly between the parents. The markers developed and candidate genes identified in this study shall be useful for the molecular breeding of tomato exhibiting increased late blight resistance and for the cloning of the Ph-2 gene.

scholarly journals Sequence Diversity of the Bacillus thuringiensis and B. cereus Sensu Lato Flagellin (H Antigen) Protein: Comparison with H Serotype Diversity

2006 ◽  
Vol 72 (7) ◽  
pp. 4653-4662 ◽  
Author(s):  
Dong Xu ◽  
Jean-Charles Côté
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bacillus Thuringiensis ◽  
Nucleotide Sequences ◽  
Amino Acid Sequences ◽  
Sequence Diversity ◽  
The Other ◽  
Bacillus Halodurans ◽  
V Region ◽  
H Serotypes

ABSTRACT We set out to analyze the sequence diversity of the Bacillus thuringiensis flagellin (H antigen [Hag]) protein and compare it with H serotype diversity. Some other Bacillus cereus sensu lato species and strains were added for comparison. The internal sequences of the flagellin (hag) alleles from 80 Bacillus thuringiensis strains and 16 strains from the B. cereus sensu lato group were amplified and cloned, and their nucleotide sequences were determined and translated into amino acids. The flagellin allele nucleotide sequences for 10 additional strains were retrieved from GenBank for a total of 106 Bacillus species and strains used in this study. These included 82 B. thuringiensis strains from 67 H serotypes, 5 B. cereus strains, 3 Bacillus anthracis strains, 3 Bacillus mycoides strains, 11 Bacillus weihenstephanensis strains, 1 Bacillus halodurans strain, and 1 Bacillus subtilis strain. The first 111 and the last 66 amino acids were conserved. They were referred to as the C1 and C2 regions, respectively. The central region, however, was highly variable and is referred to as the V region. Two bootstrapped neighbor-joining trees were generated: a first one from the alignment of the translated amino acid sequences of the amplified internal sequences of the hag alleles and a second one from the alignment of the V region amino acid sequences, respectively. Of the eight clusters revealed in the tree inferred from the entire C1-V-C2 region amino acid sequences, seven were present in corresponding clusters in the tree inferred from the V region amino acid sequences. With regard to B. thuringiensis, in most cases, different serovars had different flagellin amino acid sequences, as might have been expected. Surprisingly, however, some different B. thuringiensis serovars shared identical flagellin amino acid sequences. Likewise, serovars from the same H serotypes were most often found clustered together, with exceptions. Indeed, some serovars from the same H serotype carried flagellins with sufficiently different amino acid sequences as to be located on distant clusters. Species-wise, B. halodurans, B. subtilis, and B. anthracis formed specific branches, whereas the other four species, all in the B. cereus sensu lato group, B. mycoides, B. weihenstephanensis, B. cereus, and B. thuringiensis, did not form four specific clusters as might have been expected. Rather, strains from any of these four species were placed side by side with strains from the other species. In the B. cereus sensu lato group, B. anthracis excepted, the distribution of strains was not species specific.

scholarly journals VARIATION OF MUTAGENIC ACTION ON NONSENSE MUTANTS AT DIFFERENT SITES IN THE ISO-1-CYTOCHROME c GENE OF YEAST

Genetics ◽  
1974 ◽  
Vol 78 (1) ◽  
pp. 97-113
Author(s):  
Fred Sherman ◽  
John W Stewart
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cytochrome C ◽  
Base Pair ◽  
Nitrous Acid ◽  
Nucleotide Sequences ◽  
Mutagenic Action ◽  
Base Pairs ◽  
Wide Range ◽  
Cytochromes C

ABSTRACT Three ochre and two amber mutants in yeast have been definitively identified by the amino acid replacements in iso-1-cytochromes c from intragenic revertants. Except for rare and sometimes unusual changes, all of the replacements were single amino acids whose codons differed from UAA or UAG by one base. These assignments, which were based on the absence of tryptophan replacements in ochre revertants, could be corroborated from the studies of two groups of suppressors that were shown to act on either the ochre or amber mutants. All five nonsense mutants are located at different sites in the cyc1 gene and all are at sites that can be occupied by amino acids having a wide range of structures. The relative frequencies of the amino acid replacements indicate that identical codons located at different sites may respond differently to a mutagenic agent. Notably glutamine replacements occurred almost exclusively in UV-induced revertants of only one ochre mutant cyc1-9, but not at all or at reduced proportions in the others. Similarly, lysine replacements occurred almost exclusively in the NA-induced revertants of only the ochre mutant cyc1-72, but not at all in the others. These and other results reveal that mutation of A·T base pairs by UV and nitrous acid are dependent upon the location of the codon within the gene as well as the location of the base pair within the codon. From these findings, it appears as if the type of base-pair changes induced by UV and nitrous acid are strongly influenced by adjacent nucleotide sequences.

scholarly journals A complex resistance locus in Solanum americanum recognizes a conserved Phytophthora effector

2020 ◽  
Author(s):  
Kamil Witek ◽  
Xiao Lin ◽  
Hari S Karki ◽  
Florian Jupe ◽  
Agnieszka I Witek ◽  
...  
Keyword(s):  
Late Blight ◽  
Broad Spectrum ◽  
Durable Resistance ◽  
Late Blight Resistance ◽  
Potato Production ◽  
Blight Resistance ◽  
Resistance Locus ◽  
Family Diversity ◽  
Long Read ◽  
Solanum Americanum

AbstractLate blight caused by Phytophthora infestans greatly constrains potato production. Many Resistance (R) genes were cloned from wild Solanum species and/or introduced into potato cultivars by breeding. However, individual R genes have been overcome by P. infestans evolution; durable resistance remains elusive. We positionally cloned a new R gene, Rpi-amr1, from Solanum americanum, that encodes an NRC helper-dependent CC-NLR protein. Rpi-amr1 confers resistance in potato to all 19 P. infestans isolates tested. Using association genomics and long-read RenSeq, we defined eight additional Rpi-amr1 alleles from different S. americanum and related species. Despite only ∼90% identity between Rpi-amr1 proteins, all confer late blight resistance but differentially recognize Avramr1 orthologs and paralogs. We propose that Rpi-amr1 gene family diversity facilitates detection of diverse paralogs and alleles of the recognized effector, enabling broad-spectrum and durable resistance against P. infestans.

scholarly journals 551 Inheritance of Tomato Late Blight Resistance Derived from Lycopersicon hirsutum LA1033 and Identification of Molecular Markers

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 490E-490 ◽  
Author(s):  
Rebecca C. Lough ◽  
R.G. Gardner
Keyword(s):  
Molecular Markers ◽  
Late Blight ◽  
Field Trial ◽  
Durable Resistance ◽  
Gene Pyramiding ◽  
Late Blight Resistance ◽  
Recurrent Parent ◽  
Lycopersicon Hirsutum ◽  
Test Results ◽  
Or Gene

During the last century Phytophthora infestans (Mont.) de Bary, which causes the devastating disease late blight of tomato and potato, has been controlled with pesticides. Recently, the difficulty of controlling late blight has increased due to the appearance of new strains of P. infestans that are more virulent and are resistant to metalaxyl. Numerous P. infestans resistance genes exist within the Solanaceae; however, most of these are race-specific and have the potential of being overcome. To achieve durable resistance, it may be necessary to utilize multigenic resistance or gene pyramiding. The Lycopersicon hirsutum Kunth accession LA1033 is highly resistant to P. infestans. To incorporate resistance into a useful background, the L. esculentum Miller inbred line NC215E was used as a recurrent parent in backcrossing with L. hirsutum LA1033. A population of 264 BC3F1 plants derived from 11 BC2F2 families was planted at Fletcher and Waynesville, N.C., in July 1998 in a replicated field trial. BC3F2 seed were collected from a single highly resistant BC3F1 plant. The BC3F2 population was tested for resistance using a detached leaf screen. To verify growth chamber test results, BC3F3 seeds were collected from the BC3F2 individuals and were planted in a field trial at Fletcher in July 1999. The ratio of resistant to susceptible progeny fit the expected ratio for an incompletely dominant trait controlled by two loci. To identify molecular markers linked to the resistance loci, DNA was extracted from the highly resistant and susceptible BC3F2 individuals, and bulks of DNA were constructed. The resistant and susceptible bulks were screened with AFLP (amplified fragment length polymorphism) markers. Results of the AFLP study indicate marker linkage to resistance.

Sign in / Sign up

Export Citation Format

Share Document