scholarly journals Analysis of Epichloë festucae small secreted proteins in the interaction with Lolium perenne

2018 ◽  
Author(s):  
Barry Scott ◽  
Berit Hassing ◽  
David Winter ◽  
Carl Mesarich ◽  
Carla Eaton ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Vital Role ◽  
Effector Proteins ◽  
Secreted Proteins ◽  
In Planta ◽  
Dynamic Features ◽  
Symbiotic Interaction ◽  
Extracellular Medium ◽  
Epichloë Festucae ◽  
Small Secreted Proteins

Epichloë festucae is an endophyte of the agriculturally important perennial ryegrass. This species systemically colonises the aerial tissues of this host where its growth is tightly regulated thereby maintaining a mutualistic symbiotic interaction. Recent studies have suggested that small secreted proteins, termed effectors, play a vital role in the suppression of host defence responses. To date only a few effectors with important roles in mutualistic interactions have been described. Here we make use of the fully assembled E. festucae genome and EffectorP to generate a suite of 141 effector candidates. These were analysed with respect to their genome location and expression profiles in planta and in several symbiosis-defective mutants. We found an association between effector candidates and a class of transposable elements known as MITEs, but no correlation with other dynamic features of the E. festucae genome, such as transposable element-rich regions. Three effector candidates and a small GPI-anchored protein were chosen for functional analysis based on their high expression in planta compared to in culture and their differential regulation in symbiosis defective E. festucae mutants. All three candidate effector proteins were shown to possess a functional signal peptide and two could be detected in the extracellular medium by western blotting. Localization of the effector candidates in planta suggests that they are not translocated into the plant cell, but rather, are localized in the apoplastic space or are attached to the cell wall. Deletion and overexpression of the effector candidates, as well as the putative GPI-anchored protein, did not affect the plant growth phenotype or restrict growth of E. festucae mutants in planta. These results indicate that these proteins are either not required for the interaction at the observed life stages or that there is redundancy between effectors expressed by E. festucae.

scholarly journals The Epichloë festucae Antifungal Protein Efe-AfpA Is Also a Possible Effector Protein Required for the Interaction of the Fungus with its Host Grass Festuca rubra subsp. rubra

2021 ◽  
Vol 9 (1) ◽  
pp. 140
Author(s):  
Ruying Wang ◽  
Simin Luo ◽  
Bruce B. Clarke ◽  
Faith C. Belanger
Keyword(s):  
Disease Resistance ◽  
Insect Resistance ◽  
Effector Proteins ◽  
Antifungal Protein ◽  
Grass Species ◽  
Effector Protein ◽  
Festuca Rubra ◽  
Symbiotic Interaction ◽  
Red Fescue ◽  
Epichloë Festucae

Strong creeping red fescue (Festuca rubra subsp. rubra) is a commercially important low-maintenance turfgrass and is often naturally infected with the fungal endophyte Epichloë festucae. Epichloë spp. are endophytes of several cool-season grass species, often conferring insect resistance to the grass hosts due to the production of toxic alkaloids. In addition to insect resistance, a unique feature of the strong creeping red fescue/E. festucae symbiosis is the endophyte-mediated disease resistance to the fungal pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Such disease resistance is not a general feature of other grass/ Epichloë interactions. E. festucae isolates infecting red fescue have an antifungal protein gene Efe-afpA, whereas most other Epichloë spp. do not have a similar gene. The uniqueness of this gene suggests it may, therefore, be a component of the unique disease resistance seen in endophyte-infected red fescue. Here, we report the generation of CRISPR-Cas9 Efe-afpA gene knockouts with the goal of determining if absence of the protein in endophyte-infected Festuca rubra leads to disease susceptibility. However, it was not possible to infect plants with the knockout isolates, although infection was possible with the wild type E. festucae and with complemented isolates. This raises the interesting possibility that, in addition to having antifungal activity, the protein is required for the symbiotic interaction. The antifungal protein is a small secreted protein with high expression in planta relative to its expression in culture, all characteristics consistent with effector proteins. If Efe-AfpA is an effector protein it must be specific to certain interactions, since most Epichloë spp. do not have such a gene in their genomes.

scholarly journals Expression of several Phytophthora cinnamomi putative RxLRs provides evidence for virulence roles in avocado

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254645
Author(s):  
Melissa Joubert ◽  
Robert Backer ◽  
Juanita Engelbrecht ◽  
Noëlani van den Berg
Keyword(s):  
Phytophthora Cinnamomi ◽  
Expression Profiles ◽  
Functional Characterization ◽  
Effector Proteins ◽  
Virulence Determinants ◽  
In Planta ◽  
Phytophthora Root Rot ◽  
Host Immune Responses ◽  
Rxlr Effectors ◽  
Pathogen Fitness

Phytophthora cinnamomi is a plant pathogenic oomycete that causes Phytophthora root rot of avocado (PRR). Currently, there is a limited understanding of the molecular interactions underlying this disease. Other Phytophthora species employ an arsenal of effector proteins to manipulate host physiology, of which the RxLR effectors contribute to virulence by interfering with host immune responses. The aim of this study was to identify candidate RxLR effectors in P. cinnamomi that play a role in establishing PRR, and to infer possible functions for these effectors. We identified 61 candidate RxLR genes which were expressed during infection of a susceptible avocado rootstock. Several of these genes were present in multiple copies in the P. cinnamomi genome, suggesting that they may contribute to pathogen fitness. Phylogenetic analysis of the manually predicted RxLR protein sequences revealed 12 P. cinnamomi RxLRs that were related to characterised effectors in other Phytophthora spp., providing clues to their functions in planta. Expression profiles of nine more RxLRs point to possible virulence roles in avocado–highlighting a way forward for studies of this interaction. This study represents the first investigation of the expression of P. cinnamomi RxLR genes during the course of avocado infection, and puts forward a pipeline to pinpoint effector genes with potential as virulence determinants, providing a foundation for the future functional characterization of RxLRs that contribute to P. cinnamomi virulence in avocado.

scholarly journals Chitin Deacetylases are Required for Epichloë festucae Endophytic Cell Wall Remodelling During Establishment of a Mutualistic Symbiotic Interaction with Lolium perenne

2021 ◽  
Author(s):  
Nazanin Noorifar ◽  
Matthew Savoian ◽  
Arvina Ram ◽  
Yonathan Lukito ◽  
Berit Hassing ◽  
...  
Keyword(s):  
Cell Wall ◽  
Lolium Perenne ◽  
Molecular Probes ◽  
Symbiotic Association ◽  
In Planta ◽  
Intercellular Spaces ◽  
Free Living ◽  
Chitin Deacetylase ◽  
Symbiotic Interaction ◽  
Epichloë Festucae

Epichloë festucae forms a mutualistic symbiotic association with Lolium perenne. This biotrophic fungus systemically colonizes the intercellular spaces of aerial tissues to form an endophytic hyphal network, and also grows as an epiphyte. However, little is known about the cell wall remodelling mechanisms required to avoid host defence and maintain intercalary growth within the host. Here we use a suite of molecular probes to show that the E. festucae cell wall is remodelled by conversion of chitin to chitosan during infection of L. perenne seedlings as the hyphae switch from free-living to endophytic growth. When hyphae transition from endophytic to epiphytic growth the cell wall is remodelled from predominantly chitosan to chitin. This conversion from chitin to chitosan is catalysed by chitin deacetylase. The genome of E. festucae encodes three putative chitin deacetylases, two of which (cdaA and cdaB) are expressed in planta. Deletion of either of these genes results in disruption of fungal intercalary growth in the intercellular spaces of plants infected with these mutants. These results establish that these two genes are required for maintenance of the mutualistic symbiotic interaction between E. festucae and L. perenne.

scholarly journals A Functional Screen to Characterize the Secretomes of Eukaryotic Pathogens and Their Hosts In Planta

2006 ◽  
Vol 19 (12) ◽  
pp. 1368-1377 ◽  
Author(s):  
Sang-Jik Lee ◽  
Brendan S. Kelley ◽  
Cynthia M. B. Damasceno ◽  
Bonnie St. John ◽  
Byung-Soo Kim ◽  
...  
Keyword(s):  
Infected Plant ◽  
Effector Proteins ◽  
Secreted Proteins ◽  
Vector System ◽  
In Planta ◽  
Functional Screen ◽  
Genes Encoding ◽  
Experimental Approaches ◽  
Genome Scale ◽  
Infected Plant Material

Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast play crucial roles in surveillance, assault, defense, and counter-defense. High-throughput genome-scale strategies are being developed to better understand the nature of these “secretomes” and the identity of pathogen-derived effector proteins that subvert plant defenses and promote pathogenicity. Although combined bioinformatic and experimental approaches recently have provided comprehensive coverage of secreted proteins from bacterial phytopathogens, far less is known about the secretomes and batteries of effectors of eukaryotic phytopathogens; notably fungi and oomycetes. The yeast secretion trap (YST) represents a potentially valuable technique to simultaneously target pathogen and host secretomes in infected plant material. A YST screen, using a new vector system, was applied to study the interaction between tomato (Solanum lycopersicum) and the oomycete Phytophthora infestans, revealing sets of genes encoding secreted proteins from both pathogen and host. Most of those from the oomycete had no identifiable function and were detectable in planta only during pathogenesis, underlining the value of YST as a tool to identify new candidate effectors and pathogenicity factors. In addition, the majority of the P. infestans proteins had homologs in the genomes of the related oomycetes P. sojae and P. ramorum.

scholarly journals The Conifer Root and Stem Rot Pathogen (Heterobasidion parviporum): Effectome Analysis and Roles in Interspecific Fungal Interactions

2019 ◽  
Vol 7 (12) ◽  
pp. 658
Author(s):  
Zilan Wen ◽  
Zhen Zeng ◽  
Fei Ren ◽  
Fred O. Asiegbu
Keyword(s):  
Expression Patterns ◽  
Physical Contact ◽  
Secreted Proteins ◽  
Stem Rot ◽  
Dual Culture ◽  
In Planta ◽  
Zone Formation ◽  
Fungal Interactions ◽  
Small Secreted Proteins

Heterobasidion parviporum Niemelä & Korhonen is an economically important basidiomycete, causing root and stem rot disease of Norway spruce (Picea abies (L.) Karst) in Northern Europe. The H. parviporum genome encodes numerous small secreted proteins, which might be of importance for interacting with mycorrhiza symbionts, endophytes, and other saprotrophs. We hypothesized that small secreted proteins from H. parviporum (HpSSPs) are involved in interspecific fungal interaction. To identify HpSSP-coding genes potentially involved, we screened the H. parviporum effectome and compared their transcriptomic profiles during fungal development and in planta tree infection. We further conducted phylogenetic analysis, and identified a subset of hypothetical proteins with nonpredicted domain or unknown function as HpSSPs candidates for further characterization. The HpSSPs candidates were selected based on high-quality sequence, cysteine residue frequency, protein size, and in planta expression. We subsequently explored their roles during in vitro interaction in paired cultures of H. parviporum with ectomycorrhizal Cortinarius gentilis, endophytic Phialocephala sphaeroides, saprotrophs (Mycena sp., Phlebiopsis gigantea, and Phanerochaete chrysosporium), respectively. The transcriptomic profile revealed that a large proportion of effector candidates was either barely expressed or highly expressed under all growth conditions. In vitro dual-culture test showed that P. sphaeroides and C. gentilis were overgrown by H. parviporum. The barrage zone formation or no physical contact observed in paired cultures with the saprotrophs suggest they had either combative interaction or antibiosis effect with H. parviporum. Several HpSSPs individuals were up- or downregulated during the nonself interactions. The results of HpSSPs gene expression patterns provide additional insights into the diverse roles of SSPs in tree infection and interspecific fungal interactions.

scholarly journals Analysis of Epichloë festucae small secreted proteins in the interaction with Lolium perenne

PLoS ONE ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. e0209463 ◽  
Author(s):  
Berit Hassing ◽  
David Winter ◽  
Yvonne Becker ◽  
Carl H. Mesarich ◽  
Carla J. Eaton ◽  
...  
Keyword(s):  
Lolium Perenne ◽  
Secreted Proteins ◽  
Epichloë Festucae ◽  
Small Secreted Proteins

scholarly journals Genome-wide identification and analysis of the CNGC gene family in maize

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5816 ◽  
Author(s):  
Lidong Hao ◽  
Xiuli Qiao
Keyword(s):  
Gene Family ◽  
Expression Profiles ◽  
Gene Families ◽  
Regulatory Elements ◽  
Vital Role ◽  
Signal Pathways ◽  
Cis Acting ◽  
Genome Wide ◽  
Gramineous Plant ◽  
Gated Channel

As one of the non-selective cation channel gene families, the cyclic nucleotide-gated channel (CNGC) gene family plays a vital role in plant physiological processes that are related to signal pathways, plant development, and environmental stresses. However, genome-wide identification and analysis of the CNGC gene family in maize has not yet been undertaken. In the present study, twelve ZmCNGC genes were identified in the maize genome, which were unevenly distributed on chromosomes 1, 2, 4, 5, 6, 7, and 8. They were classified into five major groups: Groups I, II, III, IVa, and IVb. Phylogenetic analysis showed that gramineous plant CNGC genes expanded unequally during evolution. Group IV CNGC genes emerged first, whereas Groups I and II appeared later. Prediction analysis of cis-acting regulatory elements showed that 137 putative cis-elements were related to hormone-response, abiotic stress, and organ development. Furthermore, 120 protein pairs were predicted to interact with the 12 ZmCNGC proteins and other maize proteins. The expression profiles of the ZmCNGC genes were expressed in tissue-specific patterns. These results provide important information that will increase our understanding of the CNGC gene family in maize and other plants.

scholarly journals Predicting Students' Attention Level with Interpretable Facial and Head Dynamic Features in an Online Tutoring System (Student Abstract)

2020 ◽  
Vol 34 (10) ◽  
pp. 13895-13896 ◽  
Author(s):  
Shimeng Peng ◽  
Lujie Chen ◽  
Chufan Gao ◽  
Richard Jiarui Tong
Keyword(s):  
Mean Squared Error ◽  
Video Recording ◽  
Vital Role ◽  
Dynamic Features ◽  
Learning Context ◽  
Tutoring System ◽  
Consensus Definition ◽  
Online Tutoring ◽  
Mouth Movement ◽  
Synchronized Measurements

Engaged learners are effective learners. Even though it is widely recognized that engagement plays a vital role in learning effectiveness, engagement remains to be an elusive psychological construct that is yet to find a consensus definition and reliable measurement. In this study, we attempted to discover the plausible operational definitions of engagement within an online learning context. We achieved this goal by first deriving a set of interpretable features on dynamics of eyes, head and mouth movement from facial landmarks extractions of video recording when students interacting with an online tutoring system. We then assessed their predicative value for engagement which was approximated by synchronized measurements from commercial EEG brainwave headset worn by students. Our preliminary results show that those features reduce root mean-squared error by 29% compared with default predictor and we found that the random forest model performs better than a linear regressor.

scholarly journals Genome context influences evolutionary flexibility of nearly identical type III effectors in two phytopathogenic Pseudomonads

2021 ◽  
Author(s):  
David A Baltrus ◽  
Qian Feng ◽  
Brian H Kvitko
Keyword(s):  
Pseudomonas Syringae ◽  
Evolutionary Dynamics ◽  
Effector Proteins ◽  
In Planta ◽  
Genomic Context ◽  
Type Iii Effectors ◽  
Type Iii ◽  
Genome Context ◽  
The Impact ◽  
Multiple Type

Integrative Conjugative Elements (ICEs) are replicons that can insert and excise from chromosomal locations in a site specific manner, can conjugate across strains, and which often carry a variety of genes useful for bacterial growth and survival under specific conditions. Although ICEs have been identified and vetted within certain clades of the agricultural pathogen Pseudomonas syringae, the impact of ICE carriage and transfer across the entire P. syringae species complex remains underexplored. Here we identify and vet an ICE (PmaICE-DQ) from P. syringae pv. maculicola ES4326, a strain commonly used for laboratory virulence experiments, demonstrate that this element can excise and conjugate across strains, and contains loci encoding multiple type III effector proteins. Moreover, genome context suggests that another ICE (PmaICE-AOAB) is highly similar in comparison with and found immediately adjacent to PmaICE-DQ within the chromosome of strain ES4326, and also contains multiple type III effectors. Lastly, we present passage data from in planta experiments that suggests that genomic plasticity associated with ICEs may enable strains to more rapidly lose type III effectors that trigger R-gene mediated resistance in comparison to strains where nearly isogenic effectors are not present in ICEs. Taken together, our study sheds light on a set of ICE elements from P. syringae pv. maculicola ES4326 and highlights how genomic context may lead to different evolutionary dynamics for shared virulence genes between strains.

scholarly journals An ancient antimicrobial protein co-opted by a fungal plant pathogen for in planta mycobiome manipulation

2021 ◽  
Author(s):  
Nick Snelders ◽  
Gabriella Petti ◽  
Grardy van den Berg ◽  
Michael Seidl ◽  
Bart Thomma
Keyword(s):  
Life Stage ◽  
Antibacterial Properties ◽  
Plant Evolution ◽  
Effector Proteins ◽  
Plant Colonization ◽  
Antimicrobial Protein ◽  
In Planta ◽  
Antimicrobial Proteins ◽  
Pathogenic Microbes ◽  
Plant Microbiome

Microbes typically secrete a plethora of molecules to promote niche colonization. Soil-dwelling microbes are well-known producers of antimicrobials that are exploited to outcompete microbial co-inhabitants. Also plant pathogenic microbes secrete a diversity of molecules into their environment for niche establishment. Upon plant colonization, microbial pathogens secrete so-called effector proteins that promote disease development. While such effectors are typically considered to exclusively act through direct host manipulation, we recently reported that the soil-borne fungal xylem-colonizing vascular wilt pathogen Verticillium dahliae exploits effector proteins with antibacterial properties to promote host colonization through the manipulation of beneficial host microbiota. Since fungal evolution preceded land plant evolution, we now speculate that a subset of the pathogen effectors involved in host microbiota manipulation evolved from ancient antimicrobial proteins of terrestrial fungal ancestors that served in microbial competition prior to the evolution of plant pathogenicity. Here, we show that V. dahliae has co-opted an ancient antimicrobial protein as effector, named VdAMP3, for mycobiome manipulation in planta. We show that VdAMP3 is specifically expressed to ward off fungal niche competitors during resting structure formation in senescing mesophyll tissues. Our findings indicate that effector-mediated microbiome manipulation by plant pathogenic microbes extends beyond bacteria and also concerns eukaryotic members of the plant microbiome. Finally, we demonstrate that fungal pathogens can exploit plant microbiome-manipulating effectors in a life-stage specific manner, and that a subset of these effectors has evolved from ancient antimicrobial proteins of fungal ancestors that likely originally functioned in manipulation of terrestrial biota.

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