Trends in MPMI
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Molecular Plant Microbe Interaction
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Frontiers | 14-3-3 Proteins in Plant Hormone Signaling: Doing Several Things at Once | Plant Science

Frontiers | 14-3-3 Proteins in Plant Hormone Signaling: Doing Several Things at Once | Plant Science | Trends in MPMI | Scoop.it
In this review we highlight the advances achieved in the investigation of the role of 14-3-3 proteins in hormone signaling, biosynthesis, and transport. 14-3-3 proteins are a family of conserved molecules that target a number of protein clients through their ability to recognize well-defined phosphorylated motifs. As a result, they regulate several cellular processes, ranging from metabolism to transport, growth, development, and stress response. High-throughput proteomic data and two-hybrid screen demonstrate that 14-3-3 proteins physically interact with many protein clients involved in the biosynthesis or signaling pathways of the main plant hormones, while increasing functional evidence indicates that 14-3-3-target interactions play pivotal regulatory roles. These advances provide a framework of our understanding of plant hormone action, suggesting that 14-3-3 proteins act as hubs of a cellular web encompassing different signaling pathways, transducing and integrating diverse hormone signals in the regulation of physiological processes.

Via Christophe Jacquet
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Molecular Cell: A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase (2018)

Molecular Cell: A Regulatory Module Controlling Homeostasis of a Plant Immune Kinase (2018) | Trends in MPMI | Scoop.it

Plant pattern recognition receptors (PRRs) perceive microbial and endogenous molecular patterns to activate immune signaling. The cytoplasmic kinase BIK1 acts downstream of multiple PRRs as a rate-limiting component, whose phosphorylation and accumulation are central to immune signal propagation. Previous work identified the calcium-dependent protein kinase CPK28 and heterotrimeric G proteins as negative and positive regulators of BIK1 accumulation, respectively. However, mechanisms underlying this regulation remain unknown. Here we show that the plant U-box proteins PUB25 and PUB26 are homologous E3 ligases that mark BIK1 for degradation to negatively regulate immunity. We demonstrate that the heterotrimeric G proteins inhibit PUB25/26 activity to stabilize BIK1, whereas CPK28 specifically phosphorylates conserved residues in PUB25/26 to enhance their activity and promote BIK1 degradation. Interestingly, PUB25/26 specifically target non-activated BIK1, suggesting that activated BIK1 is maintained for immune signaling. Our findings reveal a multi-protein regulatory module that enables robust yet tightly regulated immune responses.


Via The Sainsbury Lab
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Genome Biology: RNA virus interference via CRISPR/Cas13a system in plants (2018)

Genome Biology: RNA virus interference via CRISPR/Cas13a system in plants (2018) | Trends in MPMI | Scoop.it

Background. CRISPR/Cas systems confer immunity against invading nucleic acids and phages in bacteria and archaea. CRISPR/Cas13a (known previously as C2c2) is a class 2 type VI-A ribonuclease capable of targeting and cleaving single-stranded RNA (ssRNA) molecules of the phage genome. Here, we employ CRISPR/Cas13a to engineer interference with an RNA virus, Turnip Mosaic Virus (TuMV), in plants.

 

Results. CRISPR/Cas13a produces interference against green fluorescent protein (GFP)-expressing TuMV in transient assays and stable overexpression lines of Nicotiana benthamiana. CRISPR RNA (crRNAs) targeting the HC-Pro and GFP sequences exhibit better interference than those targeting other regions such as coat protein (CP) sequence. Cas13a can also process pre-crRNAs into functional crRNAs.

 

Conclusions. Our data indicate that CRISPR/Cas13a can be used for engineering interference against RNA viruses, providing a potential novel mechanism for RNA-guided immunity against RNA viruses and for other RNA manipulations in plants.


Via Kamoun Lab @ TSL
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ROP GTPases Structure-Function and Signaling Pathways

ROP GTPases Structure-Function and Signaling Pathways | Trends in MPMI | Scoop.it
Rho of Plants (ROP) proteins, also known as RACs, are the plant-specific subfamily of Rho small GTP-binding proteins, referred to here as small G proteins (Zheng and Yang, 2000a; Brembu et al., 2006; Eliáš and Klimeš, 2012). Like other members of the Ras superfamily of small G proteins, ROPs function as molecular switches due to changes in conformation upon GTP binding and hydrolysis (Berken and Wittinghofer, 2008). The conformational differences between the GTP- and GDP-bound states facilitate transient interactions with effector and regulatory proteins that, in turn, result in periodic activation/inactivation cycles of signaling cascades. Small G protein function is characterized by two central features: (1) due to inefficient GTP hydrolysis, these proteins remain in the GTP-bound active form for extended periods of time; and (2) due to the low dissociation coefficient of GDP, its release is inefficient and depends on enzymatic activity (Bourne et al., 1991; Vetter and Wittinghofer, 2001). Because of these features, the GTP-/GDP-dependent activation/inactivation cycles of small G proteins are regulated in time and space by GDP/GTP Exchange Factors (GEFs) that facilitate the release of GDP and GTPase-Activating Proteins (GAPs) that enhance GTP hydrolysis (Berken and Wittinghofer, 2008).
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A plant effector‐triggered immunity signaling sector is inhibited by pattern‐triggered immunity

A plant effector‐triggered immunity signaling sector is inhibited by pattern‐triggered immunity | Trends in MPMI | Scoop.it
Since signaling machineries for two modes of plant‐induced immunity, pattern‐triggered immunity (PTI) and effector‐triggered immunity (ETI), extensively overlap, PTI and ETI signaling likely interact. In an Arabidopsis quadruple mutant, in which four major sectors of the signaling network, jasmonate, ethylene, PAD4, and salicylate, are disabled, the hypersensitive response (HR) typical of ETI is abolished when the Pseudomonas syringae effector AvrRpt2 is bacterially delivered but is intact when AvrRpt2 is directly expressed in planta. These observations led us to discovery of a network‐buffered signaling mechanism that mediates HR signaling and is strongly inhibited by PTI signaling. We named this mechanism the ETI‐Mediating and PTI‐Inhibited Sector (EMPIS). The signaling kinetics of EMPIS explain apparently different plant genetic requirements for ETI triggered by different effectors without postulating different signaling machineries. The properties of EMPIS suggest that information about efficacy of the early immune response is fed back to the immune signaling network, modulating its activity and limiting the fitness cost of unnecessary immune responses.
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GM banana shows promise against deadly fungus strain

GM banana shows promise against deadly fungus strain | Trends in MPMI | Scoop.it

GM banana shows promise against deadly fungus strain
By Erik StokstadNov. 17, 2017 , 3:04 PM

A field trial in Australia has shown that genetically modified banana trees can resist the deadly fungus that causes Panama disease, which has devastated banana crops in Asia, Africa, and Australia and is a major threat for banana growers in the Americas. The transgenic plants might reach some farmers in as few as 5 years, but it’s unclear whether consumers will bite. The work may encourage plant breeders using traditional techniques to create resistant varieties.

Bananas, one of the world’s most popular fruits, are a staple for more than 400 million people and a huge export business. In the 1950s, a soil-dwelling fungus destroyed Latin American crops of the most popular variety at the time, Gros Michel; it was replaced by a resistant variety, Cavendish, which now makes up more than 40% of harvests worldwide. In the 1990s, the Cavendish’s own nemesis surfaced in Southeast Asia: a related fungus called Fusarium wilt tropical race 4 (TR4).

Fungicides can’t control TR4; disinfecting boots and farm tools helps, but not enough. TR4 was detected in the Middle East in 2012 and appeared in Mozambique a year later. It has reached all banana-growing regions of China and was confirmed in Laos and Vietnam this year. Only the Americas have been spared so far. “This is an extremely important crop with major problems,” says study co-author Gert Kema, a plant pathologist and banana breeder at Wageningen University & Research in the Netherlands.


Via Saclay Plant Sciences
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Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus

Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus | Trends in MPMI | Scoop.it
Magnaporthe oryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M. oryzae-derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M. oryzae was examined by targeting three predicted pathogenicity genes, MoABC1, MoMAC1 and MoPMK1. Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M. oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.

Via Elsa Ballini
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Genotyping-by-Sequencing-Based Genetic Analysis of African Rice Cultivars and Association Mapping of Blast Resistance Genes Against Magnaporthe oryzae Populations in Africa

Genotyping-by-Sequencing-Based Genetic Analysis of African Rice Cultivars and Association Mapping of Blast Resistance Genes Against Magnaporthe oryzae Populations in Africa | Trends in MPMI | Scoop.it
Understanding the genetic diversity of rice germplasm is important for the sustainable use of genetic materials in rice breeding and production. Africa is rich in rice genetic resources that can be utilized to boost rice productivity on the continent. A major constraint to rice production in Africa is rice blast, caused by the hemibiotrophic fungal pathogen Magnaporthe oryzae. In this report, we present the results of a genotyping-by-sequencing (GBS)-based diversity analysis of 190 African rice cultivars and an association mapping of blast resistance (R) genes and quantitative trait loci (QTLs). The 190 African cultivars were clustered into three groups based on the 184K single nucleotide polymorphisms generated by GBS. We inoculated the rice cultivars with six African M. oryzae isolates. Association mapping identified 25 genomic regions associated with blast resistance (RABRs) in the rice genome. Moreover, PCR analysis indicated that RABR_23 is associated with the Pi-ta gene on chromosome 12. Our study demonstrates that the combination of GBS-based genetic diversity population analysis and association mapping is effective in identifying rice blast R genes/QTLs that contribute to resistance against African populations of M. oryzae. The identified markers linked to the RABRs and 14 highly resistant cultivars in this study will be useful for rice breeding in Africa.

Via Elsa Ballini
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Construction and application of functional gene modules to regulatory pathways in rice

Construction and application of functional gene modules to regulatory pathways in rice | Trends in MPMI | Scoop.it
Signal transduction and transcriptional regulation pathways are key elements in the control of diverse physiological responses and agronomic traits in plants. The regulatory roles of more than 1,000 known genes have been functionally characterized in rice, a model crop plant, and many of them are associated with transcriptional regulation and signal transduction pathways. In this study, we collected and analyzed 417 known genes associated with regulatory pathways, about 40% of the known genes, using the regulation overview installed in the MapMan toolkit. Connecting novel genes to current knowledge about regulatory pathways can elucidate their molecular functions and inspire ideas for further applications. We have summarized the functions of known regulatory genes in the areas of transcriptional regulation, epigenetic regulation, protein modification, protein degradation, signaling and hormone metabolism, also we have emphasized the unique features of several gene families in these classes, including MADS box families, which are strongly associated with the regulation of floral organ identity and flowering time. In addition, our construction of functional modules in four agronomic categories, morphological, physiological, biotic stress and abiotic stress, suggests a basic framework for expanding current knowledge about regulatory pathways to enhance agronomic traits in rice. We also provide a quick illustration of the positive and negative regulatory relationships of the target gene to manipulate agronomic trait by using genome-wide transcriptome data of knockout or overexpression mutations of genes of interest in each functional module

Via Elsa Ballini
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A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens 

A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens  | Trends in MPMI | Scoop.it
Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr9.02, associated with resistance to three important foliar maize diseases—southern leaf blight, gray leaf spot and northern leaf blight—has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr9.02 conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.
 

Via Yogesh Gupta
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The receptor-like cytoplasmic kinase BSR1 mediates chitin-induced defense signaling in rice cells

The receptor-like cytoplasmic kinase BSR1 mediates chitin-induced defense signaling in rice cells | Trends in MPMI | Scoop.it
Broad-Spectrum Resistance 1 (BSR1) encodes a rice receptor-like cytoplasmic kinase, and enhances disease resistance when overexpressed. Rice plants overexpressing BSR1 are highly resistant to diverse pathogens, including rice blast fungus. However, the mechanism responsible for this resistance has not been fully characterized. To analyze the BSR1 function, BSR1-knockout (BSR1-KO) plants were generated using a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system. Experiments using suspension-cultured cells revealed that defense responses including H2O2 production (i.e. oxidative burst) and expression of defense-related genes induced by autoclaved conidia of the rice blast fungus significantly decreased in BSR1-KO cells. Furthermore, a treatment with chitin oligomers which function as microbe-associated molecular patterns (MAMPs) of the rice blast fungus resulted in considerably suppressed defense responses in BSR1-KO cells. These results suggest that BSR1 is important for the rice innate immunity triggered by the perception of chitin.

Via Jonathan Plett, Elsa Ballini
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A computational interactome for prioritizing genes associated with complex agronomic traits in rice (Oryza sativa)

A computational interactome for prioritizing genes associated with complex agronomic traits in rice (Oryza sativa) | Trends in MPMI | Scoop.it
Rice (Oryza sativa) is one of the most important staple foods for more than half of the global population. Many rice traits are quantitative, complex and controlled by multiple interacting genes. Thus, a full understanding of genetic relationships will be critical to systematically identify genes controlling agronomic traits. We developed a genome-wide rice protein–protein interaction network (RicePPINet, http://netbio.sjtu.edu.cn/riceppinet) using machine learning with structural relationship and functional information. RicePPINet contained 708 819 predicted interactions for 16 895 non-transposable element related proteins. The power of the network for discovering novel protein interactions was demonstrated through comparison with other publicly available protein–protein interaction (PPI) prediction methods, and by experimentally determined PPI data sets. Furthermore, global analysis of domain-mediated interactions revealed RicePPINet accurately reflects PPIs at the domain level. Our studies showed the efficiency of the RicePPINet-based method in prioritizing candidate genes involved in complex agronomic traits, such as disease resistance and drought tolerance, was approximately 2–11 times better than random prediction. RicePPINet provides an expanded landscape of computational interactome for the genetic dissection of agronomically important traits in rice.

Via Elsa Ballini
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Trends in Microbiology: Rise of a Cereal Killer: The Biology of Magnaporthe oryzae Biotrophic Growth (2018)

Trends in Microbiology: Rise of a Cereal Killer: The Biology of Magnaporthe oryzae Biotrophic Growth (2018) | Trends in MPMI | Scoop.it

The rice blast fungus, Magnaporthe oryzae, causes one of the most destructive diseases of cultivated rice in the world. Infections caused by this recalcitrant pathogen lead to the annual destruction of approximately 10–30% of the rice harvested globally. The fungus undergoes extensive developmental changes to be able to break into plant cells, build elaborate infection structures, and proliferate inside host cells without causing visible disease symptoms. From a molecular standpoint, we are still in the infancy of understanding how M. oryzae manipulates the host during this complex multifaceted infection. Here, we describe recent advances in our understanding of the cell biology of M. oryzae biotrophic interaction and key molecular factors required for the disease establishment in rice cells.


Via Kamoun Lab @ TSL
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bioRxiv: Resistance gene discovery and cloning by sequence capture and association genetics (2018)

bioRxiv: Resistance gene discovery and cloning by sequence capture and association genetics (2018) | Trends in MPMI | Scoop.it
Genetic resistance is the most economic and environmentally sustainable approach for crop disease protection. Disease resistance (R) genes from wild relatives are a valuable resource for breeding resistant crops. However, introgression of R genes into crops is a lengthy process often associated with co-integration of deleterious linked genes and pathogens can rapidly evolve to overcome R genes when deployed singly. Introducing multiple cloned R genes into crops as a stack would avoid linkage drag and delay emergence of resistance-breaking pathogen races. However, current R gene cloning methods require segregating or mutant progenies, which are difficult to generate for many wild relatives due to poor agronomic traits. We exploited natural pan-genome variation in a wild diploid wheat by combining association genetics with R gene enrichment sequencing (AgRenSeq) to clone four stem rust resistance genes in <6 months. RenSeq combined with diversity panels is therefore a major advance in isolating R genes for engineering broad-spectrum resistance in crops.

Via The Sainsbury Lab
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With a free pass, CRISPR-edited plants reach market in record time

With a free pass, CRISPR-edited plants reach market in record time | Trends in MPMI | Scoop.it

CRISPR–Cas9-edited plants can be cultivated and sold free from regulation, the US Department of Agriculture (USDA) is making increasingly clear. The agency gave a free pass to Camelina sativa, or false flax, with enhanced omega-3 oil. And more recently, in October, said that a drought-tolerant soybean variety developed with CRISPR falls outside of its regulatory purview....


Via Loïc Lepiniec
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Jonathan Lapleau's curator insight, January 11, 8:34 AM
CRISPR crops are developing so fast ! This is a good news for agriculture and consumers. But unfortunately, not in Europe...
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Plant Elite Squad: First Defense Line and Resistance Genes – Identification, Diversity and Functional Roles

Plant Elite Squad: First Defense Line and Resistance Genes – Identification, Diversity and Functional Roles | Trends in MPMI | Scoop.it
Plants exhibit sensitive mechanisms to respond to environmental stresses, presenting some specific and non-specific reactions when attacked by pathogens, including organisms from different classes and complexity, as viroids, viruses, bacteria, fungi and nematodes. A crucial step to define the fate of the plant facing an invading pathogen is the activation of a compatible Resistance (R) gene, the focus of the present review. Different aspects regarding R-genes and their products are discussed, including pathogen recognition mechanisms, signaling and effects on induced and constitutive defense processes, splicing and post transcriptional mechanisms involved. There are still countless challenges to the complete understanding of the mechanisms involving R-genes in plants, in particular those related to the interactions with other genes of the pathogen and of the host itself, their regulation, acting mechanisms at transcriptional and post-transcriptional levels, as well as the influence of other types of stress over their regulation. A magnification of knowledge is expected when considering the novel information from the omics and systems biology.
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New Phytologist: Plasmodesmal regulation during plant–pathogen interactions (2017)

New Phytologist: Plasmodesmal regulation during plant–pathogen interactions (2017) | Trends in MPMI | Scoop.it

Plasmodesmata (PD) are plasma membrane-lined pores that connect neighbouring plant cells, bridging the cell wall and establishing cytoplasmic and membrane continuity between cells. PD are dynamic structures regulated by callose deposition in a variety of stress and developmental contexts. This process crudely controls the aperture of the pore and thus the flux of molecules between cells. During pathogen infection, plant cells initiate a range of immune responses and it was recently identified that, following perception of fungal and bacterial pathogens, plant cells initially close their PD. Systemic defence responses depend on the spread of signals between cells, raising questions about whether PD are in different functional states during different immune responses. It is well established that viral pathogens exploit PD to spread between cells, but it has more recently been identified that protein effectors secreted by fungal pathogens can spread between host cells via PD. It is possible that many classes of pathogens specifically target PD to aid infection, which would infer antagonistic regulation of PD by host and pathogen. How PD regulation benefits both host immune responses and pathogen infection is an important question and demands that we examine the multicellular nature of plant–pathogen interactions.


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Co-transformation mediated stacking of blast resistance genes Pi54 and Pi54rh in rice provides broad spectrum resistance against Magnaporthe oryzae

Co-transformation mediated stacking of blast resistance genes Pi54 and Pi54rh in rice provides broad spectrum resistance against Magnaporthe oryzae | Trends in MPMI | Scoop.it
This is the first report of stacking two major blast resistance genes in blast susceptible rice variety using co-transformation method to widen the resistance spectrum against different isolates of Magnaporthe oryzae.

Via Elsa Ballini
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bioRxiv: Positively selected effector genes and their contribution to virulence in the smut fungus Sporisorium reilianum (2017)

bioRxiv: Positively selected effector genes and their contribution to virulence in the smut fungus Sporisorium reilianum (2017) | Trends in MPMI | Scoop.it

Plants and fungi display a broad range of interactions within natural and agricultural ecosystems ranging from symbiosis to parasitism. Pathogenic interactions are governed by secreted fungal effector proteins, which are thought to coevolve with their host targets. Biotrophic smut fungi which belong to the division of Basidiomycota are well-suited to investigate the evolution of plant pathogens, because several quality draft genomes and genetic tools are available for these species. Here, we used the genomes of Sporisorium reilianum f. sp. zeae and S. reilianum f. sp. reilianum, two closely related formae speciales infecting maize and sorghum, respectively, together with the genomes of Ustilago hordei, U. maydis and S. scitamineum to identify effector genes showing signs of positive selection. The largest numbers of such genes were identified in the two pathovariants of S. reilianum and between paralogues in U. hordei, where many belong to families showing species-specific expansions. Next, we assessed the contribution to virulence of candidate effector genes in S. reilianum f. sp. zeae by deletion of individual genes in a solopathogenic strain. While eight of nine deletions mutants were unaffected in virulence, one mutant had lost virulence. This shows that despite the relatively recent divergent time of the two formae speciales, a signature of positive selection in candidate effector genes in S. reilianum is a poor indicator for the identification of genes with virulence functions.


Via Kamoun Lab @ TSL
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Broad-spectrum blast resistance: harnessing a natural allele of a transcription factor in rice

Broad-spectrum blast resistance: harnessing a natural allele of a transcription factor in rice | Trends in MPMI | Scoop.it
The model illustrates that a mutation in Bsr-d1 promoter in ‘Digu’ recruits a transcriptional repressor MYBS1, which suppresses BSR-D1 expression, leading to  decreased peroxidase expression and higher H2O2 levels after M. oryzae infection in the  blast-resistant rice variety (‘Digu’) compared with a susceptible variety (‘LTH’).

Via Philip Carella, Elsa Ballini
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Vesicle trafficking in plant immunity

Vesicle trafficking in plant immunity | Trends in MPMI | Scoop.it

Highlights


• SNAREs are the minimal core factors to drive vesicle fusion events in plants.
• Extracellular immune proteins travel along the default secretory pathway.
• Plant surface immune receptors are endocytosed and degraded upon activated.
• Oomycete/fungal pathogens highjack the vacuole-targeted PVCs/MVBs.



To defend against extracellular pathogens, plants primarily depend on cell-autonomous innate immunity due to the lack of the circulatory immune system including mobile immune cells. To extracellularly restrict or kill the pathogens, plant cells dump out antimicrobials. However, since antimicrobials are also toxic to plant cells themselves, they have to be safely delivered to the target sites in a separate vesicular compartment. In addition, because immune responses often requires energy otherwise used for the other metabolic processes, it is very important to properly control the duration and strength of immune responses depending on pathogen types. This can be achieved by regulating the sensing of immune signals and the delivery/discharge of extracellular immune molecules, all of which are controlled by membrane trafficking in plant cells. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are now considered as the minimal factors that can merge two distinct membranes of cellular compartments. Hence, in this review, known and potential immune functions of SNAREs as well as regulatory proteins will be discussed.

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High throughput phenotyping to accelerate crop breeding and monitoring of diseases in the field.

High throughput phenotyping to accelerate crop breeding and monitoring of diseases in the field. | Trends in MPMI | Scoop.it
Highlights • Phenotyping technology can increase the throughput of plant screening in the field. • Early season detection of plant diseases is key to reducing crop yield losses. • Disease diagnosis relies on symptom recognition through observations and ratings. • Remote sensing methods can identify, quantify and monitor plant diseases. • Sensor-based phenotyping will accelerate the rate of genetic gain in crops. Effective implementation of technology that facilitates accurate and high-throughput screening of thousands of field-grown lines is critical for accelerating crop improvement and breeding strategies for higher yield and disease tolerance. Progress in the development of field-based high throughput phenotyping methods has advanced considerably in the last 10 years through technological progress in sensor development and high-performance computing. Here, we review recent advances in high throughput field phenotyping technologies designed to inform the genetics of quantitative traits, including crop yield and disease tolerance. Successful application of phenotyping platforms to advance crop breeding and identify and monitor disease requires: (1) high resolution of imaging and environmental sensors; (2) quality data products that facilitate computer vision, machine learning and GIS; (3) capacity infrastructure for data management and analysis; and (4) automated environmental data collection. Accelerated breeding for agriculturally relevant crop traits is key to the development of improved varieties and is critically dependent on high-resolution, high-throughput field-scale phenotyping technologies that can efficiently discriminate better performing lines within a larger population and across multiple environments.
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Plant Cell: The RxLR Motif of the Host Targeting Effector AVR3a of Phytophthora infestans Is Cleaved Before Secretion (2017)

Plant Cell: The RxLR Motif of the Host Targeting Effector AVR3a of Phytophthora infestans Is Cleaved Before Secretion (2017) | Trends in MPMI | 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 are 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) 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.


Via Kamoun Lab @ TSL
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Transposon-Mediated NLR Exile to the Pollen Allows Rice Blast Resistance without Yield Penalty

Transposon-Mediated NLR Exile to the Pollen Allows Rice Blast Resistance without Yield Penalty | Trends in MPMI | Scoop.it
In crop breeding, the goal is to maximize yield and disease resistance. In this spotlight, we highlight an elegant case of NLR-mediated durable resistance in rice, which is effective against the devastating fungus Magnaporthe oryzae, but does not involve yield penalty. The genetic and molecular dissection of this broad-spectrum resistance has unraveled a fascinating epigenetic regulatory mechanism balancing blast resistance and yield that opens exciting new perspectives for crop improvement.

Via Elsa Ballini
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