Phytophthora biology
5.2K views | +0 today
Follow
Phytophthora biology
New discoveries in the genus Phytophthora.
Your new post is loading...
Your new post is loading...
Scooped by Niklaus Grunwald
Scoop.it!

Multiple origins of downy mildews and mito-nuclear discordance within the paraphyletic genus Phytophthora

Multiple origins of downy mildews and mito-nuclear discordance within the paraphyletic genus Phytophthora | Phytophthora biology | Scoop.it
Phylogenetic relationships between thirteen species of downy mildew and 103 species of Phytophthora (plant-pathogenic oomycetes) were investigated with two nuclear and four mitochondrial loci, using several likelihood-based approaches. Three Phytophthora taxa and all downy mildew taxa were excluded from the previously recognized subgeneric clades of Phytophthora, though all were strongly supported within the paraphyletic genus. Downy mildews appear to be polyphyletic, with graminicolous downy mildews (GDM), brassicolous downy mildews (BDM) and downy mildews with colored conidia (DMCC) forming a clade with the previously unplaced Phytophthora taxon totara; downy mildews with pyriform haustoria (DMPH) were placed in their own clade with affinities to the obligate biotrophic P. cyperi. Results suggest the recognition of four additional clades within Phytophthora, but few relationships between clades could be resolved. Trees containing all twenty extant downy mildew genera were produced by adding partial coverage of seventeen additional downy mildew taxa; these trees supported the monophyly of the BDMs, DMCCs and DMPHs but suggested that the GDMs are paraphyletic in respect to the BDMs or polyphyletic. Incongruence between nuclear-only and mitochondrial-only trees suggests introgression may have occurred between several clades, particularly those containing biotrophs, questioning whether obligate biotrophic parasitism and other traits with polyphyletic distributions arose independently or were horizontally transferred. Phylogenetic approaches may be limited in their ability to resolve some of the complex relationships between the “subgeneric” clades of Phytophthora, which include twenty downy mildew genera and hundreds of species.
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Sudden oak death task force fight for funding

Sudden oak death task force fight for funding | Phytophthora biology | Scoop.it
The Sudden Oak Death Task Force will once again be appealing for funds during Oregon’s February legislative session, where they will ask for an additional $1 million to eradicate NA-1
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

A functional genomics database for plant microbiome studies

A functional genomics database for plant microbiome studies | Phytophthora biology | Scoop.it
Most of the interaction between microbes and plants occurs at the interface between the roots and soil. In Nature Genetics, a team led by JGI researchers isolated novel bacteria from plant root environments and combined the new genomes with thousands of publicly available genomes representing the major groups of plant-associated bacteria, and bacteria from plant and non-plant environments. Through the resulting database, researchers identified genes enriched in the genomes of plant-associated and root-associated organisms.
more...
No comment yet.
Rescooped by Niklaus Grunwald from Adaptive Evolution and Speciation
Scoop.it!

Lifestyle, gene gain and loss, and transcriptional remodeling cause divergence in the transcriptomes of Phytophthora infestans and Pythium ultimum during potato tuber colonization - BMC Genomics

Lifestyle, gene gain and loss, and transcriptional remodeling cause divergence in the transcriptomes of Phytophthora infestans and Pythium ultimum during potato tuber colonization - BMC Genomics | Phytophthora biology | Scoop.it
Background
How pathogen genomes evolve to support distinct lifestyles is not well-understood. The oomycete Phytophthora infestans, the potato blight agent, is a largely biotrophic pathogen that feeds from living host cells, which become necrotic only late in infection. The related oomycete Pythium ultimum grows saprophytically in soil and as a necrotroph in plants, causing massive tissue destruction. To learn what distinguishes their lifestyles, we compared their gene contents and expression patterns in media and a shared host, potato tuber.

Results
Genes related to pathogenesis varied in temporal expression pattern, mRNA level, and family size between the species. A family’s aggregate expression during infection was not proportional to size due to transcriptional remodeling and pseudogenization. Ph. infestans had more stage-specific genes, while Py. ultimum tended towards more constitutive expression. Ph. infestans expressed more genes encoding secreted cell wall-degrading enzymes, but other categories such as secreted proteases and ABC transporters had higher transcript levels in Py. ultimum. Species-specific genes were identified including new Pythium genes, perforins, which may disrupt plant membranes. Genome-wide ortholog analyses identified substantial diversified expression, which correlated with sequence divergence. Pseudogenization was associated with gene family expansion, especially in gene clusters.

Conclusion
This first large-scale analysis of transcriptional divergence within oomycetes revealed major shifts in genome composition and expression, including subfunctionalization within gene families. Biotrophy and necrotrophy seem determined by species-specific genes and the varied expression of shared pathogenicity factors, which may be useful targets for crop protection.

Via Ronny Kellner
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

New strain of deadly disease infects SW Oregon tree saplings

New strain of deadly disease infects SW Oregon tree saplings | Phytophthora biology | Scoop.it
An aggressive strain of the disease that causes sudden oak death in plants has infected Douglas fir and grand fir saplings in southwest Oregon.
more...
No comment yet.
Rescooped by Niklaus Grunwald from bioinformatics-databases
Scoop.it!

Oomycetes Transcriptomics Database

Oomycetes Transcriptomics Database | Phytophthora biology | Scoop.it

Oomycetes Transcriptomics Database is an integrated transcriptome and EST data resource for oomycete pathogens. The database currently stores processed ABI SOLiD transcript sequences from Phytophthora sojae mycelial and plant infection libraries as well as Illumina transcript sequences from five Hyaloperonospora arabidopsidis libraries. In addition to those resources, it has also a complete set of Sanger EST sequences from P. sojae, P. infestans and H. arabidopsidis grown under various conditions. A new web-based transcriptome browser was created for visualization of assembled transcripts, their mapping to the reference genome, expression profiling and depth of read coverage for a particular location on the genome. The transcriptome browser merges EST derived contigs with NGS derived assembled transcripts on the fly and displays the consensus. OTD possesses strong query features and the database interacts with VBI Microbial Database as well as the Phytophthora Transcriptomics Database. The legacy EST data of P.sojae comes from 10 libraries e.g; sHA, sHB, sMA, sML, sMY, sMC, sZG, sZO, sZS, iMY with a total of 33350 raw sequences. Additionally, there are 99,320 EST sequences fromP.infestans from NCBI. For P.infestans sequences cleaning information is not available. These sequences are clustered and assembled and data analysis was performed by us. We have separated Soybean ESTs from P.sojae libraries using insillico methods. The soybean libraries are named as gHA and gHB based on their origin from sHA or sHB.


Via Dr. Stefan Gruenwald
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Plan set to fight tree disease

Plan set to fight tree disease | Phytophthora biology | Scoop.it
Rep. David Brock Smith, U.S. Sen. Jeff Merkley and scores of stakeholders have outlined their plan to combat Sudden Oak Death (SOD), which threatens the environmental and economic vitality of Curry and its surrounding counties. “The risk to our communities, economy and environment is too high to delay any longer
more...
No comment yet.
Rescooped by Niklaus Grunwald from Fungal|Oomycete Biology
Scoop.it!

Transcriptomic and metabolomic analyses of cucumber fruit peels reveal a developmental increase in terpenoid glycosides associated with age-related resistance to Phytophthora capsici

Transcriptomic and metabolomic analyses of cucumber fruit peels reveal a developmental increase in terpenoid glycosides associated with age-related resistance to Phytophthora capsici | Phytophthora biology | Scoop.it

The oomycete, Phytophthora capsici, infects cucumber (Cucumis sativus L.) fruit. An age-related resistance (ARR) to this pathogen was previously observed in fruit of cultivar ‘Vlaspik’ and shown to be associated with the peel. Young fruits are highly susceptible, but develop resistance at ~10–12 days post pollination (dpp). Peels from resistant (16 dpp) versus susceptible (8 dpp) age fruit are enriched with genes associated with defense, and methanolic extracts from resistant age peels inhibit pathogen growth. Here we compared developing fruits from ‘Vlaspik’ with those of ‘Gy14’, a line that does not exhibit ARR. Transcriptomic analysis of peels of the two lines at 8 and 16 dpp identified 80 genes that were developmentally upregulated in resistant ‘Vlaspik’ 16 dpp versus 8 dpp, but not in susceptible ‘Gy14’ at 16 dpp. A large number of these genes are annotated to be associated with defense and/or specialized metabolism, including four putative resistance (R) genes, and numerous genes involved in flavonoid and terpenoid synthesis and decoration. Untargeted metabolomic analysis was performed on extracts from 8 and 16 dpp ‘Vlaspik’ and ‘Gy14’ fruit peels using Ultra-Performance Liquid Chromatography and Quadrupole Time-of-Flight Mass Spectrometry. Multivariate analysis of the metabolomes identified 113 ions uniquely abundant in resistant ‘Vlaspik’ 16 dpp peel extracts. The most abundant compounds in this group had relative mass defects consistent with terpenoid glycosides. Two of the three most abundant ions were annotated as glycosylated nor-terpenoid esters. Together, these analyses reveal potential mechanisms by which ARR to P. capsici may be conferred.


Via Alejandro Rojas
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

A Disease That’s Felled Forests in California And Oregon Shows up in Washington

A Disease That’s Felled Forests in California And Oregon Shows up in Washington | Phytophthora biology | Scoop.it
A disease commonly known as “sudden oak death” has decimated forests in California and infected forests in Oregon. And now it’s made its way north to Washington where rhododendrons, douglas firs, and western larches are most susceptible. It has the potential for disastrous effects.



more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Evolutionary dynamics on any population structure : Nature : Nature Research

Evolutionary dynamics on any population structure : Nature : Nature Research | Phytophthora biology | Scoop.it
Evolution occurs in populations of reproducing individuals. The structure of a population can affect which traits evolve. Understanding evolutionary game dynamics in structured populations remains difficult. Mathematical results are known for special structures in which all individuals have the same number of neighbours. The general case, in which the number of neighbours can vary, has remained open. For arbitrary selection intensity, the problem is in a computational complexity class that suggests there is no efficient algorithm. Whether a simple solution for weak selection exists has remained unanswered. Here we provide a solution for weak selection that applies to any graph or network. Our method relies on calculating the coalescence times of random walks. We evaluate large numbers of diverse population structures for their propensity to favour cooperation. We study how small changes in population structure—graph surgery—affect evolutionary outcomes. We find that cooperation flourishes most in societies that are based on strong pairwise ties.
more...
No comment yet.
Rescooped by Niklaus Grunwald from Plant Pathogenomics
Scoop.it!

bioRxiv: Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen (2017)

bioRxiv: Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen (2017) | Phytophthora biology | Scoop.it

Outbreaks caused by asexual lineages of fungal and oomycete pathogens are an expanding threat to crops, wild animals and natural ecosystems (Fisher et al. 2012, Kupferschmidt 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl and Thomma 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Cooke et al. 2012, Yoshida et al. 2013, Yoshida et al. 2014). Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by compared sibling strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Forbes et al. 1997, Oyarzun et al. 1998, Delgado et al. 2013, Yoshida et al. 2013, Yoshida et al. 2014). We detected numerous examples of structural variation, nucleotide polymorphisms and gene conversion within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. These results highlight the exceptional genetic and phenotypic plasticity that underpins host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen.


Via Kamoun Lab @ TSL
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

A paralogous decoy protects Phytophthora sojae apoplastic effector PsXEG1 from a host inhibitor

A paralogous decoy protects Phytophthora sojae apoplastic effector PsXEG1 from a host inhibitor | Phytophthora biology | Scoop.it
The extracellular space (apoplast) of plant tissue represents a critical battleground between plants and attacking microbes. Here we show that a pathogen-secreted apoplastic xyloglucan-specific endoglucanase, PsXEG1, is a focus of this struggle in the Phytophthora sojae–soybean interaction. We show that soybean produces an apoplastic glucanase inhibitor protein, GmGIP1, that binds to PsXEG1 to block its contribution to virulence. P. sojae, however, secretes a paralogous PsXEG1-like protein, PsXLP1, that has lost enzyme activity but binds to GmGIP1 more tightly than does PsXEG1, thus freeing PsXEG1 to support P. sojae infection. The gene pair encoding PsXEG1 and PsXLP1 is conserved in many Phytophthora species, and the P. parasitica orthologs PpXEG1 and PpXLP1 have similar functions. Thus, this apoplastic decoy strategy may be widely used in Phytophthora pathosystems.
more...
No comment yet.
Rescooped by Niklaus Grunwald from Plant Pathogenomics
Scoop.it!

Genome Biol Evol: Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod rot, underwent increases in genome sizes and gene numbers by different mechanisms (2017)

Genome Biol Evol: Phytophthora megakarya and P. palmivora, closely related causal agents of cacao black pod rot, underwent increases in genome sizes and gene numbers by different mechanisms (2017) | Phytophthora biology | Scoop.it

Phytophthora megakarya (Pmeg) and P. palmivora (Ppal) are closely related species causing cacao black pod rot. While Ppal is a cosmopolitan pathogen, cacao is the only known host of economic importance for Pmeg. Pmeg is more virulent on cacao than Ppal. We sequenced and compared the Pmeg and Ppal genomes and identified virulence-related putative gene models (PGeneM) that may be responsible for their differences in host specificities and virulence. Pmeg and Ppal have estimated genome sizes of 126.88 and 151.23 Mb and PGeneM numbers of 42,036 and 44,327, respectively. The evolutionary histories of Pmeg and Ppal appear quite different. Post-speciation, Ppal underwent whole-genome duplication whereas Pmeg has undergone selective increases in PGeneM numbers, likely through accelerated transposable element driven duplications. Many PGeneMs in both species failed to match transcripts and may represent pseudogenes or cryptic genetic reservoirs. Pmeg appears to have amplified specific gene families, some of which are virulence-related. Analysis of mycelium, zoospore and in planta transcriptome expression profiles using neural network self-organizing map analysis generated 24 multi-variate and non-linear self-organizing map classes. Many members of the RxLR, NPP, and pectinase genes families were specifically induced in planta. Pmeg displays a diverse virulence-related gene complement similar in size to and potentially of greater diversity than Ppal but it remains likely that the specific functions of the genes determine each species’ unique characteristics as pathogens.


Via Kamoun Lab @ TSL
more...
Rescooped by Niklaus Grunwald from Adaptive Evolution and Speciation
Scoop.it!

Phytophthora methylomes modulated by expanded 6mA methyltransferases are associated with adaptive genome regions - bioRxiv

Phytophthora methylomes modulated by expanded 6mA methyltransferases are associated with adaptive genome regions - bioRxiv | Phytophthora biology | Scoop.it

Filamentous plant pathogen genomes often display a bipartite architecture with gene sparse, repeat-rich compartments serving as a cradle for adaptive evolution. However, the extent to which this "two-speed" genome architecture is associated with genome-wide epigenetic modifications is unknown. Here, we show that the oomycete plant pathogens Phytophthora infestans and Phytophthora sojae possess functional adenine N6-methylation (6mA) methyltransferases that modulate patterns of 6mA marks across the genome. In contrast, 5-methylcytosine (5mC) could not be detected in the two Phytophthora species. Methylated DNA IP Sequencing (MeDIP-seq) of each species revealed that 6mA is depleted around the transcriptional starting sites (TSS) and is associated with low expressed genes, particularly transposable elements. Remarkably, genes occupying the gene-sparse regions have higher levels of 6mA compared to the remainder of both genomes, possibly implicating the methylome in adaptive evolution of Phytophthora. Among three putative adenine methyltransferases, DAMT1 and DAMT3 displayed robust enzymatic activities. Surprisingly, single knockouts of each of the 6mA methyltransferases in P. sojae significantly reduced in vivo 6mA levels, indicating that the three enzymes are not fully redundant. MeDIP-seq of the damt3 mutant revealed uneven patterns of 6mA methylation across genes, suggesting that PsDAMT3 may have a preference for gene body methylation after the TSS. Our findings provide evidence that 6mA modification is an epigenetic mark of Phytophthora genomes and that complex patterns of 6mA methylation by the expanded 6mA methyltransferases may be associated with adaptive evolution in these important plant pathogens.


Via Kamoun Lab @ TSL, Francis Martin, Ronny Kellner
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

The RxLR Motif of the Host Targeting Effector AVR3a of Phytophthora infestans Is Cleaved before Secretion

The RxLR Motif of the Host Targeting Effector AVR3a of Phytophthora infestans Is Cleaved before Secretion | Phytophthora biology | Scoop.it

When plant-pathogenic oomycetes infect their hosts, they employ a large arsenal of effector proteins to establish a successful infection. Some effector proteins are secreted and are destined to be translocated and function inside host cells. The largest group of translocated proteins from oomycetes is the RxLR effectors, defined by their conserved N-terminal Arg-Xaa-Leu-Arg (RxLR) motif. However, the precise role of this motif in the host cell translocation process is unclear. Here, detailed biochemical studies of the RxLR effector AVR3a from the potato pathogen Phytophthora infestans are presented. Mass spectrometric analysis revealed that the RxLR sequence of native AVR3a is cleaved off prior to secretion by the pathogen and the N terminus of the mature effector was found likely to be acetylated. High-resolution NMR structure analysis of AVR3a indicates that the RxLR motif is well accessible to potential processing enzymes. Processing and modification of AVR3a is to some extent similar to events occurring with the export element ([PEXEL][1]) found in malaria effector proteins from Plasmodium falciparum . These findings imply a role for the RxLR motif in the secretion of AVR3a by the pathogen, rather than a direct role in the host cell entry process itself.

more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Rethinking the evolution of eukaryotic metabolism: novel cellular partitioning of enzymes in stramenopiles links serine biosynthesis to glycolysis in mitochondria

Rethinking the evolution of eukaryotic metabolism: novel cellular partitioning of enzymes in stramenopiles links serine biosynthesis to glycolysis in mitochondria | Phytophthora biology | Scoop.it
An important feature of eukaryotic evolution is metabolic compartmentalization, in which certain pathways are restricted to the cytosol or specific organelles. Glycolysis in eukaryotes is described as a cytosolic process. The universality of this canon has been challenged by recent genome data that suggest that some glycolytic enzymes made by stramenopiles bear mitochondrial targeting peptides. Mining of oomycete, diatom, and brown algal genomes indicates that stramenopiles encode two forms of enzymes for the second half of glycolysis, one with and the other without mitochondrial targeting peptides. The predicted mitochondrial targeting was confirmed by using fluorescent tags to localize phosphoglycerate kinase, phosphoglycerate mutase, and pyruvate kinase in Phytophthora infestans, the oomycete that causes potato blight. A genome-wide search for other enzymes with atypical mitochondrial locations identified phosphoglycerate dehydrogenase, phosphoserine aminotransferase, and phosphoserine phosphatase, which form a pathway for generating serine from the glycolytic intermediate 3-phosphoglycerate. Fluorescent tags confirmed the delivery of these serine biosynthetic enzymes to P. infestans mitochondria. A cytosolic form of this serine biosynthetic pathway, which occurs in most eukaryotes, is missing from oomycetes and most other stramenopiles. The glycolysis and serine metabolism pathways of oomycetes appear to be mosaics of enzymes with different ancestries. While some of the noncanonical oomycete mitochondrial enzymes have the closest affinity in phylogenetic analyses with proteins from other stramenopiles, others cluster with bacterial, plant, or animal proteins. The genes encoding the mitochondrial phosphoglycerate kinase and serine-forming enzymes are physically linked on oomycete chromosomes, which suggests a shared origin. Stramenopile metabolism appears to have been shaped through the acquisition of genes by descent and lateral or endosymbiotic gene transfer, along with the targeting of the proteins to locations that are novel compared to other eukaryotes. Colocalization of the glycolytic and serine biosynthesis enzymes in mitochondria is apparently necessary since they share a common intermediate. The results indicate that descriptions of metabolism in textbooks do not cover the full diversity of eukaryotic biology.
more...
Scooped by Niklaus Grunwald
Scoop.it!

Chetco Bar Fire may slow spread of sudden oak death in Oregon tanoaks

The USDA has quarantined part of Oregon's south coast to keep the disease contained.
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

The sudden oak death epidemic in Oregon

The sudden oak death epidemic in Oregon | Phytophthora biology | Scoop.it
Oregon nurseries are increasingly threatened by the repeated expansion of the sudden oak death (SOD) epidemic in Curry County. Although this epidemic is geographically far away from the main nurser…
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

“Good-Guy” Fungus to Take on Killer of Oaks and Ornamental Crops

“Good-Guy” Fungus to Take on Killer of Oaks and Ornamental Crops | Phytophthora biology | Scoop.it
A beneficial soil fungus could offer a biobased approach to battling Phytophthora ramorum, a pathogen that kills oaks, other tree species and woody ornamentals. BioWorks, Inc. of Victor, New York, is collaborating with Agricultural Research Service (ARS) plant pathologist Tim Widmer to commercially formulate the fungus, Trichoderma asperellum. The species is a mycoparasite, meaning it attacks and kills other [...]
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Plan to bring death to Sudden Oak Death

Plan to bring death to Sudden Oak Death | Phytophthora biology | Scoop.it
CURRY COUNTY — A recently-formed Sudden Oak Death Task Force released its plan to combat the disease in Southwest Oregon on Monday.
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Millions of California oak trees are dying

Millions of California oak trees are dying | Phytophthora biology | Scoop.it
A pathogen causing a phenomenon known as ‘sudden oak death’ has killed millions of oak and tanoak trees in California’s coastal forests since 1995.
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

A Disease That’s Felled Forests in California and Oregon Shows up in Washington

A Disease That’s Felled Forests in California and Oregon Shows up in Washington | Phytophthora biology | Scoop.it
A tree disease that's decimated forests in California has made its way north to western Oregon and Washington.
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Quantitative analysis of the tomato nuclear proteome during Phytophthora capsici infection unveils regulators of immunity

Plant–pathogen interactions are complex associations driven by the interplay of host and microbe‐encoded factors. With secreted pathogen proteins (effectors) and immune signalling components found i
more...
No comment yet.
Scooped by Niklaus Grunwald
Scoop.it!

Frontiers | A perspective on CRN proteins in the genomics age: Evolution, Classification, Delivery and Function revisited | Plant Microbe Interactions

Frontiers | A perspective on CRN proteins in the genomics age: Evolution, Classification, Delivery and Function revisited | Plant Microbe Interactions | Phytophthora biology | Scoop.it
Plant associated microbes rely on secreted virulence factors (effectors) to modulate host immunity and ensure progressive infection. Amongst the secreted protein repertoires defined and studied in pathogens to date, the CRNs (for CRinkling and Necrosis) have emerged as one of only a few highly conserved protein families, spread across several kingdoms. CRN proteins were first identified in plant pathogenic oomycetes where they were found to be modular factors that are secreted and translocated inside host cells by means of a conserved N-terminal domain. Subsequent localization and functional studies have led to the view that CRN C-termini execute their presumed effector function in the host nucleus, targeting processes required for immunity. These findings have led to great interest in this large protein family and driven the identification of additional CRN-like proteins in other organisms. The identification of CRN proteins and subsequent functional studies have markedly increased the number of candidate CRN protein sequences, expanded the range of phenotypes tentatively associated with function and revealed some of their molecular functions towards virulence. The increased number of characterised CRNs also has presented a set of challenges that may impede significant progress in the future. Here, we summarise our current understanding of the CRNs and re-assess some basic assumptions regarding this protein family. We will discuss the latest findings on CRN biology and highlight exciting new hypotheses that have emanated from the field. Finally, we will discuss new approaches to study CRN functions that would lead to a better understanding of CRN effector biology as well as the processes that lead to host susceptibility and immunity.
more...
No comment yet.
Rescooped by Niklaus Grunwald from Plant Pathogenomics
Scoop.it!

MPMI: Changing ploidy as a strategy; the Irish potato Famine pathogen shifts ploidy in relation to its sexuality (2016)

MPMI: Changing ploidy as a strategy; the Irish potato Famine pathogen shifts ploidy in relation to its sexuality (2016) | Phytophthora biology | Scoop.it

The oomycete Phytophthora infestans was the causal agent of the Irish Great Famine and is a recurring threat to global food security. The pathogen can reproduce both sexually and asexually, with high potential to adapt to various environments and great risk to break disease resistance genes in potato. As other oomycetes, P. infestans is regarded to be diploid during the vegetative phase of its life cycle, although some studies reported trisomy, and polyploidy. Using microsatellite fingerprinting, genome-wide assessment of SNP polymorphism, nuclear DNA quantification, and microscopic counting of chromosome numbers we assessed the ploidy level of isolates. All progeny from sexual populations of P. infestans in nature were found to be diploid, in contrast nearly all dominant asexual lineages, including the most important pandemic clonal lineages US-1 and 13_A2 were triploid. Such triploids possess significantly more allelic variation than diploids. We observed that triploid genotype can change to a diploid genome constitution when exposed to artificial stress conditions. This study reveals that fluctuations in the ploidy level maybe a key factor in the adaptation process of this notorious plant destroyer and imposes an extra challenge to control this disease.


Via Kamoun Lab @ TSL
more...
No comment yet.