Immune activation mediated by the late blight resistance protein R1 requires nuclear localization of R1 and AVR1
Du, Y. ; Berg, J. ; Govers, F. ; Bouwmeester, K. - \ 2015
New Phytologist 207 (2015)3. - ISSN 0028-646X - p. 735 - 747.
disease-resistance - phytophthora-infestans - arabidopsis-thaliana - innate immunity - plant immunity - receptor - recognition - potato - gene - component
Resistance against oomycete pathogens is mainly governed by intracellular nucleotide-binding leucine-rich repeat (NLR) receptors that recognize matching avirulence (AVR) proteins from the pathogen, RXLR effectors that are delivered inside host cells. Detailed molecular understanding of how and where NLR proteins and RXLR effectors interact is essential to inform the deployment of durable resistance (R) genes. Fluorescent tags, nuclear localization signals (NLSs) and nuclear export signals (NESs) were exploited to determine the subcellular localization of the potato late blight protein R1 and the Phytophthora infestans RXLR effector AVR1, and to target these proteins to the nucleus or cytoplasm. Microscopic imaging revealed that both R1 and AVR1 occurred in the nucleus and cytoplasm, and were in close proximity. Transient expression of NLS- or NES-tagged R1 and AVR1 in Nicotiana benthamiana showed that activation of the R1-mediated hypersensitive response and resistance required localization of the R1/AVR1 pair in the nucleus. However, AVR1-mediated suppression of cell death in the absence of R1 was dependent on localization of AVR1 in the cytoplasm. Balanced nucleocytoplasmic partitioning of AVR1 seems to be a prerequisite. Our results show that R1-mediated immunity is activated inside the nucleus with AVR1 in close proximity and suggest that nucleocytoplasmic transport of R1 and AVR1 is tightly regulated.
Tsw gene-based resistance is triggered by a functional RNA silencing suppressor protein of the Tomato spotted wilt virus
Ronde, D. de; Butterbach, P.B.E. ; Lohuis, H. ; Hedil, M. ; Lent, J.W.M. van; Kormelink, R.J.M. - \ 2013
Molecular Plant Pathology 14 (2013)4. - ISSN 1464-6722 - p. 405 - 415.
mediated plant transformation - capsicum-chinense - cell-death - disease-resistance - lycopersicon-esculentum - viral suppressors - sw-5 gene - potato - tospovirus - agrobacterium
As a result of contradictory reports, the avirulence (Avr) determinant that triggers Tsw gene-based resistance in Capsicum annuum against the Tomato spotted wilt virus (TSWV) is still unresolved. Here, the N and NSs genes of resistance-inducing (RI) and resistance-breaking (RB) isolates were cloned and transiently expressed in resistant Capsicum plants to determine the identity of the Avr protein. It was shown that the NSsRI protein triggered a hypersensitive response (HR) in Tsw-containing Capsicum plants, but not in susceptible Capsicum, whereas no HR was discerned after expression of the NRI/RB protein, or when NSsRB was expressed. Although NSsRI was able to suppress the silencing of a functional green fluorescence protein (GFP) construct during Agrobacterium tumefaciens transient assays on Nicotiana benthamiana, NSsRB had lost this capacity. The observation that RB isolates suppressed local GFP silencing during an infection indicated a recovery of RNA silencing suppressor activity for the NSs protein or the presence of another RNA interference (RNAi) suppressor. The role of NSs as RNA silencing suppressor and Avr determinant is discussed in the light of a putative interplay between RNAi and the natural Tsw resistance gene
Arabidopsis wat1 (walls are thin1)-mediated resistance to the bacterial vascular pathogen, Ralstonia solanacearum, is accompanied by cross-regulation of salicylic acid and tryptophan metabolism
Denancé, N. ; Ranocha, P. ; Oria, N. ; Barlet, X. ; Rivière, M.P. ; Yadeta, K.A. ; Hoffmann, L. ; Perreau, F. ; Clément, G. ; Maia-Grondard, A. ; Berg, G.C.M. van den; Savelli, B. ; Fournier, S. ; Aubert, Y. ; Pelletier, S. ; Thomma, B.P.H.J. ; Molina, A. ; Jouanin, L. ; Marco, Y. ; Goffner, D. - \ 2013
The Plant Journal 73 (2013)2. - ISSN 0960-7412 - p. 225 - 239.
plant-cell wall - systemic acquired-resistance - fusarium-oxysporum - disease-resistance - wilt disease - plectosphaerella-cucumerina - medicago-truncatula - confers resistance - thaliana - mutant
Inactivation of Arabidopsis WAT1 (Walls Are Thin1), a gene required for secondary cell-wall deposition, conferred broad-spectrum resistance to vascular pathogens, including the bacteria Ralstonia solanacearum and Xanthomonas campestris pv. campestris, and the fungi Verticillium dahliae and Verticillium albo-atrum. Introduction of NahG, the bacterial salicylic acid (SA)-degrading salicylate hydroxylase gene, into the wat1 mutant restored full susceptibility to both R. solanacearum and X. campestris pv. campestris. Moreover, SA content was constitutively higher in wat1 roots, further supporting a role for SA in wat1-mediated resistance to vascular pathogens. By combining transcriptomic and metabolomic data, we demonstrated a general repression of indole metabolism in wat1-1 roots as shown by constitutive down-regulation of several genes encoding proteins of the indole glucosinolate biosynthetic pathway and reduced amounts of tryptophan (Trp), indole-3-acetic acid and neoglucobrassicin, the major form of indole glucosinolate in roots. Furthermore, the susceptibility of the wat1 mutant to R. solanacearum was partially restored when crossed with either the trp5 mutant, an over-accumulator of Trp, or Pro35S:AFB1-myc, in which indole-3-acetic acid signaling is constitutively activated. Our original hypothesis placed cell-wall modifications at the heart of the wat1 resistance phenotype. However, the results presented here suggest a mechanism involving root-localized metabolic channeling away from indole metabolites to SA as a central feature of wat1 resistance to R. solanacearum.
High resolution mapping of a novel late blight resistance gene Rpi-avll, from the wild Bolivian species Solanum avilesii
Verzaux, E.C. ; Budding, D.J. ; Vetten, N. de; Niks, R.E. ; Vleeshouwers, V.G.A.A. ; Vossen, E.A.G. van der; Jacobsen, E. ; Visser, R.G.F. - \ 2011
American Journal of Potato Research 88 (2011)6. - ISSN 1099-209X - p. 511 - 519.
marker-assisted selection - potato-virus-y - phytophthora-infestans - disease-resistance - quantitative resistance - cultivated potato - bulbocastanum - rflp - qtl - microsatellites
Both Mexico and South America are rich in Solanum species that might be valuable sources of resistance (R) genes to late blight (Phytophthora infestans). Here, we focus on an R gene present in the diploid Bolivian species S. avilesii. The genotype carrying the R gene was resistant to eight out of 10 Phytophthora isolates of various provenances. The identification of a resistant phenotype and the generation of a segregating population allowed the mapping of a single dominant R gene, Rpi-avl1, which is located in an R gene cluster on chromosome 11. This R gene cluster is considered as an R gene “hot spot”, containing R genes to at least five different pathogens. High resolution mapping of the Rpi-avl1 gene revealed a marker co-segregating in 3890 F1 individuals, which may be used for marker assisted selection in breeding programs and for further cloning of Rpi-avl1
Genetic mapping of 14 avirulence genes in an EU-B04 x 1639 progeny of Venturia inaequalis
Broggini, G.A.L. ; Bus, V.G.M. ; Parravicini, G. ; Kumar, S. ; Groenwold, R. ; Gessler, C. - \ 2011
Fungal Genetics and Biology 48 (2011)2. - ISSN 1087-1845 - p. 166 - 176.
receptor-like genes - apple scab resistance - cke wint - disease-resistance - flax rust - magnaporthe-grisea - controlling pathogenicity - durable resistance - mutant characters - melampsora-lini
Durable resistance to apple scab (Venturia inaequalis (Cke) Wint; anamorph Spilocaea pomi Fries) is one of the major goals of apple (Malus) breeding programs. Since current scab resistance breeding is heavily reliant on genes with gene-for-gene relationships, a good understanding of the genetic basis of host–pathogen interactions needs to be developed for this strategy to be successful. While the genomic organization of apple scab resistance genes has been studied extensively, little is known about the avirulence genes in the pathogen. The progeny of a cross of European V. inaequalis race (1) isolate EU-B04 and race (1,2,8,9) isolate 1639 was used to generate a genetic map based on microsatellite and AFLP markers, and investigated for inheritance of avirulence traits on 20 Malus accessions representing 17 scab resistance genes. The accessions comprised scab differential hosts (0), (1), (2), (8), and (9), and hosts carrying known as well as not previously reported secondary resistance genes, including some identified in crosses that have resistant accessions ‘Geneva’, ‘Dolgo’, Malus baccata jackii, M. micromalus, or ‘Antonovka’ in their pedigree. The latter genes appear to be narrow spectrum genes that showed gene-for-gene relationships as a segregation ratio of Avr:avr = 1:1 was observed on 12 accessions, while a ratio of 3:1 was observed on five accessions and a ratio of 7:1 on one host. All progenies were shown to be pathogenic, as all of them were able to infect hosts (0) and (1). A genetic map consisting of 15 major linkage groups (LGs) and spanning 972 cM was generated with the aid of 156 markers. The map position of 12 avirulence traits was determined: eight avirulence genes mapped into two separate clusters (1: AvrVdg2, AvrVv1, AvrVu1, AvrVrjrd; and 2: AvrVu2, AvrVh3.2, AvrVs1, AvrVu4), while four avirulence genes (AvrRvi8, AvrVv2, AvrVt57 and AvrVsv) mapped to different LGs. AvrRvi2 and AvrRvi9 also are genetically linked, but showed an interaction with AvrRvi8, the nature of which is unclear. While AvrRvi8 segregated at 1:1 ratio, the other two Avrs segregated at 3:1 ratios. However, all progeny avirulent on hosts (2) and (9) were also avirulent on host (8) and further research is required to determine the avirulence gene relationships. A further two independently segregating loci, AvrRvi1 and AvrRvi6, identified in previous studies, were mapped by inference based on their known linkage to SSR markers. The clustering of avirulence genes in V. inaequalis reflecting the clustering of resistance genes in Malus suggests this pathosystem is a classical example of an “arms race” between host and pathogen. This also seems to apply to the narrow spectrum scab resistance genes, which may imply a larger role in plant defense for these genes than has been assumed to date
Convergent evidence for a role of WIR1 proteins during the interaction of barley with the powdery mildew fungus Blumeria graminis
Douchkov, Dimitar ; Johrde, A. ; Nowara, D. ; Himmelbach, A. ; Lueck, S. ; Niks, R.E. ; Schweizer, P. - \ 2011
Journal of Plant Physiology 168 (2011)1. - ISSN 0176-1617 - p. 20 - 29.
basal host-resistance - defense-related genes - disease-resistance - functional assessment - winter-wheat - cell-death - f-sp - pathogen resistance - magnaporthe-grisea - nonhost resistance
Pathogen attack triggers a multifaceted defence response in plants that includes the accumulation of pathogenesis-related proteins and their corresponding transcripts. One of these transcripts encodes for WIR1, a small glycine- and proline-rich protein of unknown function that appears to be specific to grass species. Here we describe members of the HvWIR1 multigene family of barley with respect to phylogenetic relationship, transcript regulation, co-localization with quantitative trait loci for resistance to the barley powdery mildew fungus Blumeria graminis (DC.) E.O. Speer f.sp. hordei, the association of single nucleotide polymorphisms or gene haplotypes with resistance, as well as phenotypic effects of gene silencing by RNAi. HvWIR1 is encoded by a multigene family of moderate complexity that splits up into two major clades, one of those being also represented by previously described cDNA sequences from wheat. All analysed WIR1 transcripts accumulated in response to powdery mildew attack in leaves and all mapped WIR1 genes were associated with quantitative trait loci for resistance to B. graminis. Moreover, single nucleotide polymorphisms or haplotypes of WIR1 members were associated with quantitative resistance of barley to B. graminis, and transient WIR1 gene silencing affected the interaction of epidermal cells with the pathogen. The presented data provide convergent evidence for a role of the HvWIR1a gene and possibly other family members, during the interaction of barley with B. graminis
The phenotypic expression of QTLs for partial resistance to barley leaf rust during plant development
Wang, Lijuan ; Wang, Yajun ; Wang, Zhen ; Marcel, T.C. ; Niks, R.E. ; Qi, Xiaoquan - \ 2010
Theoretical and Applied Genetics 121 (2010)5. - ISSN 0040-5752 - p. 857 - 864.
age-related resistance - near-isogenic lines - puccinia-hordei - pseudomonas-syringae - disease-resistance - pyrenophora-teres - mosaic-virus - arabidopsis - gene - responses
Partial resistance is generally considered to be a durable form of resistance. In barley, Rphq2, Rphq3 and Rphq4 have been identified as consistent quantitative trait loci (QTLs) for partial resistance to the barley leaf rust pathogen Puccinia hordei. These QTLs have been incorporated separately into the susceptible L94 and the partially resistant Vada barley genetic backgrounds to obtain two sets of near isogenic lines (NILs). Previous studies have shown that these QTLs are not effective at conferring disease resistance in all stages of plant development. In the present study, the two sets of QTL–NILs and the two recurrent parents, L94 and Vada, were evaluated for resistance to P. hordei isolate 1.2.1 simultaneously under greenhouse conditions from the first leaf to the flag leaf stage. Effect of the QTLs on resistance was measured by development rate of the pathogen, expressed as latency period (LP). The data show that Rphq2 prolongs LP at the seedling stage (the first and second leaf stages) but has almost no effect on disease resistance in adult plants. Rphq4 showed no effect on LP until the third leaf stage, whereas Rphq3 is consistently effective at prolonging LP from the first leaf to the flag leaf. The changes in the effectiveness of Rphq2 and Rphq4 happen at the barley tillering stage (the third to fourth leaf stages). These results indicate that multiple disease evaluations of a single plant by repeated inoculations of the fourth leaf to the flag leaf should be conducted to precisely estimate the effect of Rphq4. The present study confirms and describes in detail the plant development-dependent effectiveness of partial resistance genes and, consequently, will enable a more precise evaluation of partial resistance regulation during barley development
Identification of a resistance gene Rpi-dlc1 to Phytophthora infestans in European accessions of Solanum dulcamara
Golas, T.M. ; Sikkema, A. ; Gros, J. ; Feron, R.M.C. ; Berg, R.G. van den; Weerden, G.M. van der; Mariani, C. ; Allefs, J.J.H.M. - \ 2010
Theoretical and Applied Genetics 120 (2010)4. - ISSN 0040-5752 - p. 797 - 808.
late-blight resistance - broad-spectrum resistance - race-specific resistance - potato late blight - r-gene - disease-resistance - chromosome-ix - bulbocastanum - tomato - locus
Initial screening of 14 Solanum dulcamara accessions enabled the identification of individuals resistant and susceptible to Phytophthora infestans. Crosses between contrasting genotypes resulted in three F2–BC1 populations segregating for resistance to late blight in a laboratory assay and under field conditions. Genetic profiling of one of these populations using 128 AFLP primers generated three markers linked to the resistant phenotype. Blast analysis of the sequenced markers resulted in a plausible gene position on the distal end of the long arm of chromosome 9 that could be confirmed by CAPS markers. Thus, we describe a first resistant gene, named Rpi-dlc1, from S. dulcamara, a Solanum species native to Europe. In addition, one population was tested for broadness of resistance responses using a set of seven additional P. infestans isolates, varying in virulence. This indicated the possible presence of additional Rpi genes.
A novel approach to locate Phytophthora infestans resistance genes on the potato genetic map
Jacobs, M.M.J. ; Vosman, B. ; Vleeshouwers, V.G.A.A. ; Visser, R.G.F. ; Henken, G. ; Berg, R.G. van den - \ 2010
Theoretical and Applied Genetics 120 (2010)4. - ISSN 0040-5752 - p. 785 - 796.
late-blight resistance - broad-spectrum resistance - disease-resistance - solanum-bulbocastanum - r-gene - chromosome-ix - tomato - plant - homologs - genome
Mapping resistance genes is usually accomplished by phenotyping a segregating population for the resistance trait and genotyping it using a large number of markers. Most resistance genes are of the NBS-LRR type, of which an increasing number is sequenced. These genes and their analogs (RGAs) are often organized in clusters. Clusters tend to be rather homogenous, viz. containing genes that show high sequence similarity with each other. From many of these clusters the map position is known. In this study we present and test a novel method to quickly identify to which cluster a new resistance gene belongs and to produce markers that can be used for introgression breeding. We used NBS profiling to identify markers in bulked DNA samples prepared from resistant and susceptible genotypes of small segregating populations. Markers co-segregating with resistance can be tested on individual plants and directly used for breeding. To identify the resistance gene cluster a gene belongs to, the fragments were sequenced and the sequences analyzed using bioinformatics tools. Putative map positions arising from this analysis were validated using markers mapped in the segregating population. The versatility of the approach is demonstrated with a number of populations derived from wild Solanum species segregating for P. infestans resistance. Newly identified P. infestans resistance genes originating from S. verrucosum, S. schenckii, and S. capsicibaccatum could be mapped to potato chromosomes 6, 4, and 11, respectively.
Basal host resistance of barley to powdery mildew: connecting quantitative trait loci and candidate genes
Aghnoum, R. ; Marcel, T.C. ; Johrde, A. ; Pecchioni, N. ; Schweizer, P. ; Niks, R.E. - \ 2010
Molecular Plant-Microbe Interactions 23 (2010)1. - ISSN 0894-0282 - p. 91 - 102.
heterologous rust fungi - head blight resistance - defense-related genes - hordeum-vulgare l - pisum-sativum l. - disease-resistance - leaf rust - nonhost resistance - puccinia-hordei - spring barley
The basal resistance of barley to powdery mildew (Blumeria graminis f. sp. hordei) is a quantitatively inherited trait that is based on nonhypersensitive mechanisms of defense. A functional genomic approach indicates that many plant candidate genes are involved in the defense against formation of fungal haustoria. It is not known which of these candidate genes have allelic variation that contributes to the natural variation in powdery mildew resistance, because many of them may be highly conserved within the barley species and may act downstream of the basal resistance reaction. Twenty-two expressed sequence tag or cDNA clone sequences that are likely to play a role in the barley-Blumeria interaction based on transcriptional profiling, gene silencing, or overexpression data, as well as mlo, Ror1, and Ror2, were mapped and considered candidate genes for contribution to basal resistance. We mapped the quantitative trait loci (QTL) for powdery mildew resistance in six mapping populations of barley at seedling and adult plant stages and developed an improved high-density integrated genetic map containing 6,990 markers for comparing QTL and candidate gene positions over mapping populations. We mapped 12 QTL at seedling stage and 13 QTL at adult plant stage, of which four were in common between the two developmental stages. Six of the candidate genes showed coincidence in their map positions with the QTL identified for basal resistance to powdery mildew. This co-localization justifies giving priority to those six candidate genes to validate them as being responsible for the phenotypic effects of the QTL for basal resistance
Rpi-vnt1.1, a Tm-2(2) Homolog from Solanum venturii, Confers Resistance to Potato Late Blight
Foster, S.J. ; Park, T.H. ; Pel, M. ; Brigneti, G. ; Sliwka, J. ; Jagger, L. ; Vossen, E.A.G. van der; Jones, J.D.G. - \ 2009
Molecular Plant-Microbe Interactions 22 (2009)5. - ISSN 0894-0282 - p. 589 - 600.
broad-spectrum resistance - race-specific resistance - phytophthora-infestans mont - disease-resistance - chromosome-ix - lycopersicon-esculentum - r-gene - hypersensitive resistance - united-states - aflp markers
Despite the efforts of breeders and the extensive use of fungicide control measures, late blight still remains a major threat to potato cultivation worldwide. The introduction of genetic resistance into cultivated potato is considered a valuable method to achieve durable resistance to late blight. Here, we report the identification and cloning of Rpi-vnt1.1, a previously uncharacterized late-blight resistance gene from Solanum venturii. The gene was identified by a classical genetic and physical mapping approach and encodes a coiled-coil nucleotide-binding leucine-rich repeat protein with high similarity to Tm-22 from S. lycopersicum which confers resistance against Tomato mosaic virus. Transgenic potato and tomato plants carrying Rpi-vnt1.1 were shown to be resistant to Phytophthora infestans. Of 11 P. infestans isolates tested, only isolate EC1 from Ecuador was able to overcome Rpi-vnt1.1 and cause disease on the inoculated plants. Alleles of Rpi-vnt1.1 (Rpi-vnt1.2 and Rpivnt1.3) that differed by only a few nucleotides were found in other late-blight-resistant accessions of S. venturii. The late blight resistance gene Rpi-phu1 from S. phureja is shown here to be identical to Rpi-vnt1.1, suggesting either that this strong resistance gene has been maintained since a common ancestor, due to selection pressure for blight resistance, or that genetic exchange between S. venturii and S. phureja has occurred at some time.
Does chromatin remodeling mark systemic acquired resistance?
Burg, H.A. van den; Takken, F.L.W. - \ 2009
Trends in Plant Science 14 (2009)5. - ISSN 1360-1385 - p. 286 - 294.
salicylic-acid - transcription factors - disease-resistance - histone acetylation - defense responses - gene-expression - negative regulator - plant immunity - pseudomonas-syringae - arabidopsis-thaliana
The recognition of plant pathogens activates local defense responses and triggers a long-lasting systemic acquired resistance (SAR) response. Activation of SAR requires the hormone salicylic acid (SA), which induces SA-responsive gene expression. Recent data link changes in gene expression to chromatin remodeling, such as histone modifications and histone replacement. Here, we propose a model in which recruitment of chromatin-modifying complexes to SA-responsive loci controls their basal and SA-induced expression. Basal repression of these loci requires the post-translational modifier SUMO (SMALL UBIQUITIN-LIKE MODIFIER). This is of particular relevance because SUMO conjugation has been shown to control the activity, assembly and disassembly of chromatin-modifying complexes to transcription complexes. Chromatin remodeling could be instrumental for priming of SA-responsive loci to enable their enhanced reactivation upon subsequent pathogen attack
Molecular breeding for resistance to Phytophthora infestans (Mont.) de Bary in potato (Solanum tuberosum L.): a perspective of cisgenesis
Park, T.H. ; Vleeshouwers, V.G.A.A. ; Jacobsen, E. ; Visser, R.G.F. ; Vossen, E.A.G. van der - \ 2009
Plant Breeding 128 (2009)2. - ISSN 0179-9541 - p. 109 - 117.
late-blight resistance - race-specific resistance - marker-assisted selection - broad-spectrum resistance - globodera-pallida stone - disease-resistance - quantitative resistance - gene-cluster - cultivated potato - field-resistance
Late blight caused by Phytophthora infestans is one of the most devastating diseases in potato cultivation and is mostly controlled by the application of chemicals. However, introduction of combinations of resistance (R) genes conferring broad-spectrum resistance from wild Solanum species into cultivated potatoes is considered the most practical and promising approach to achieve durable resistance. This can be realized via classical breeding or genetic modification (GM). Because classical breeding is very time-consuming and is often hampered by linkage drag, a GM approach seems logic in this heterozygous and vegetatively propagated crop. During the last decades, many R genes have been identified in several wild Solanum species. Some have been cloned and more will follow. When these genes are derived from species crossable with cultivated potato (so-called cisgenes), application in resistance breeding using a GM approach is similar to an introgression breeding approach, in that the exploited genes are indigenous to the crop. Pending deregulation or derogation of cisgenesis, the use of cisgenic R genes would be an ideal strategy to accomplish durable resistance in potato.
Mapping and Cloning of Late Blight Resistance Genes from Solanum venturii Using an Interspecific Candidate Gene Approach
Pel, M. ; Foster, S.J. ; Park, T.H. ; Rietman, H. ; Arkel, G. van; Jones, J.D.G. ; Eck, H.J. van; Jacobsen, E. ; Visser, R.G.F. ; Vossen, E.A.G. van der - \ 2009
Molecular Plant-Microbe Interactions 22 (2009)5. - ISSN 0894-0282 - p. 601 - 615.
quantitative trait locus - race-specific resistance - nbs-lrr proteins - phytophthora-infestans - disease-resistance - r-gene - nucleotide-binding - field-resistance - lycopersicon-esculentum - nicotiana-benthamiana
Late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases of potato. Resistance (R) genes from the wild species Solanum demissum have been used by breeders to generate late-blight-resistant cultivars but resistance was soon overcome by the pathogen. A more recent screening of a large number of wild species has led to the identification of novel sources of resistance, many of which are currently being characterized further. Here, we report on the cloning of dominant Rpi genes from S. venturii. Rpi-vnt1.1 and Rpi-vnt1.3 were mapped to chromosome 9 using nucleotide binding site (NBS) profiling. Subsequently, a Tm-22-based allele mining strategy was used to clone both genes. Rpi-vnt1.1 and Rpi-vnt1.3 belong to the coiled-coil NBS leucine-rich repeat (LRR) class of plant R genes and encode predicted peptides of 891 and 905 amino acids (aa), respectively, which share 75% amino acid identity with the Tomato mosaic virus resistance protein Tm-22 from tomato. Compared with Rpi-vnt1.1, Rpi-vnt1.3 harbors a 14-aa insertion in the N-terminal region of the protein and two different amino acids in the LRR domain. Despite these differences, Rpi-vnt1.1 and Rpi-vnt1.3 genes have the same resistance spectrum
Genetic mapping and transcription analyses of resistance gene loci in potato using NBS profiling
Brugmans, B.W. ; Wouters, D.C.A.E. ; Os, H. van; Hutten, R.C.B. ; Linden, C.G. van der; Visser, R.G.F. ; Eck, H.J. van; Vossen, E.A.G. van der - \ 2008
Theoretical and Applied Genetics 117 (2008)8. - ISSN 0040-5752 - p. 1379 - 1388.
disease-resistance - confers resistance - map - tomato - genome - construction - arabidopsis - proteins - sequence - analogs
NBS profiling is a method for the identification of resistance gene analog (RGA) derived fragments. Here we report the use of NBS profiling for the genome wide mapping of RGA loci in potato. NBS profiling analyses on a minimal set of F1 genotypes of the diploid mapping population previously used to generate the ultra dense (UHD) genetic map of potato, allowed us to efficiently map polymorphic RGA fragments relative to 10,000 existing AFLP markers. In total, 34 RGA loci were mapped, of which only 13 contained RGA sequences homologous to RGAs genetically positioned at approximately similar positions in potato or tomato. The remaining RGA loci mapped either at approximate chromosomal regions previously shown to contain RGAs in potato or tomato without sharing homology to these RGAs, or mapped at positions not yet identified as RGA-containing regions. In addition to markers representing RGAs with unknown functions, segregating markers were detected that were closely linked to four functional R genes that segregate in the UHD mapping population. To explore the potential of NBS profiling in RGA transcription analyses, RNA isolated from different tissues was used as template for NBS profiling. Of all the fragments amplified approximately 15% showed putative intensity or absent/present differences between different tissues suggesting putative tissue specific RGA or R gene transcription. Putative absent/present differences between individuals were also found. In addition to being a powerful tool for generating candidate gene markers linked to R gene loci, NBS profiling, when applied to cDNA, can be instrumental in identifying those members of an R gene cluster that are transcribed, and thus putatively functional.
Resistance proteins: scouts of the plant innate immune system
Tameling, W.I.L. ; Takken, F.L.W. - \ 2008
European Journal of Plant Pathology 121 (2008)3. - ISSN 0929-1873 - p. 243 - 255.
leucine-rich repeat - tobacco-mosaic-virus - membrane-associated complex - nb-lrr protein - disease-resistance - iii effector - cell-death - hypersensitive response - pseudomonas-syringae - conferring resistance
Recognition of non-self in plants is mediated by specialised receptors that upon pathogen perception trigger induction of host defence responses. Primary, or basal, defence is mainly triggered by trans-membrane receptors that recognise conserved molecules released by a variety of (unrelated) microbes. Pathogens can overcome these basal defences by the secretion of specific effectors. Subsequent recognition of these effectors by specialised receptors (called resistance proteins) triggers induction of a second layer of plant defence responses. These responses are qualitatively similar to primary defence responses; however, they are generally faster and stronger. Here we give an overview of the predicted (domain) structures of resistance proteins and their proposed mode of action as molecular switches of plant innate immunity. We also highlight recent advances revealing that some of these proteins act in the plant nucleus as transcriptional co-regulators and that crosstalk can occur between members of different resistance protein families.
The diverse roles of NB-LRR proteins in plants
Tameling, W.I.L. ; Joosten, M.H.A.J. - \ 2007
Physiological and Molecular Plant Pathology 71 (2007)4-6. - ISSN 0885-5765 - p. 126 - 134.
systemic acquired-resistance - programmed cell-death - tobacco-mosaic-virus - disease-resistance - hypersensitive response - signaling pathways - striga-asiatica - gene homologs - arabidopsis - receptor
Plant innate immunity relies on specialised immune receptors that can detect and defend against a wide variety of microbes. The first group of receptors comprises the transmembrane pathogen- or pattern-recognition receptors (PRRs), which respond to slowly evolving pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs). The second group of immune receptors is formed by the polymorphic disease resistance (R) proteins that detect microbe-derived effector proteins. Most R proteins are members of the nucleotide binding leucine-rich repeat (NB-LRR) class. Although this class comprises one of the biggest protein families in plants, relatively few have been functionally characterised to date. The question rises whether all NB-LRRs function as immune receptors, or that they might have alternative functions. The answer is: yes, they do have alternative functions that are different from the immune receptor function. This review summarises the current knowledge about non-immune receptor signal transduction functions of NB-LRRs in plants.
Tomato mitogen-activated protein kinases LeMPK1, LeMPK2, and LeMPK3 are activated during the cf-4/Avr4-induced hypersensitive response and have distinct phosphorylation specificities
Stulemeijer, I.J.E. ; Stratmann, J.W. ; Joosten, M.H.A.J. - \ 2007
Plant Physiology 144 (2007)3. - ISSN 0032-0889 - p. 1481 - 1494.
map kinase - disease-resistance - defense responses - cell-death - cladosporium-fulvum - plant immunity - mediated resistance - gene - arabidopsis - tobacco
Tomato (Solanum lycopersicum) plants with the Cf-4 resistance gene recognize strains of the pathogenic fungus Cladosporium fulvum that secrete the avirulence protein Avr4. Transgenic tomato seedlings coexpressing Cf-4 and Avr4 mount a hypersensitive response (HR) at 20°C, which is suppressed at 33°C. Within 120 min after a shift from 33°C to 20°C, tomato mitogen-activated protein (MAP) kinase (LeMPK) activity increases in Cf-4/Avr4 seedlings. Searching tomato genome databases revealed at least 16 LeMPK sequences, including the sequence of LeMPK1, LeMPK2, and LeMPK3 that cluster with biotic stress-related MAP kinase orthologs from Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum). LeMPK1, LeMPK2, and LeMPK3 are simultaneously activated in Cf-4/Avr4 seedlings, and, to reveal whether they are functionally redundant or not, recombinant LeMPKs were incubated on PepChip Kinomics slides carrying peptides with potential phosphorylation sites. Phosphorylated peptides and motifs present in them discriminated between the phosphorylation specificities of LeMPK1, LeMPK2, and LeMPK3. LeMPK1, LeMPK2, or LeMPK3 activity was specifically suppressed in Cf-4-tomato by virus-induced gene silencing and leaflets were either injected with Avr4 or challenged with C. fulvum-secreting Avr4. The results of these experiments suggested that the LeMPKs have different but also overlapping roles with regard to HR and full resistance in tomato.
How plants recognize pathogens and defend themselves
Wit, P.J.G.M. de - \ 2007
Cellular and Molecular Life Sciences 64 (2007)21. - ISSN 1420-682X - p. 2726 - 2732.
receptor-like proteins - pseudomonas-syringae - innate immunity - disease-resistance - flagellin perception - molecular-patterns - signaling pathway - effector proteins - bacterial disease - avirulence genes
Plants have an innate immunity system to defend themselves against pathogens. With the primary immune system, plants recognize microbe-associated molecular patterns (MAMPs) of potential pathogens through pattern recognition receptors (PRRs) that mediate a basal defense response. Plant pathogens suppress this basal defense response by means of effectors that enable them to cause disease. With the secondary immune system, plants have gained the ability to recognize effector-induced perturbations of host targets through resistance proteins (RPs) that mediate a strong local defense response that stops pathogen growth. Both primary and secondary immune responses in plants depend on germ line-encoded PRRs and RPs. During induction of local immune responses, systemic immune responses also become activated, which predispose plants to become more resistant to subsequent pathogen attacks. This review gives an update on recent findings that have enhanced our understanding of plant innate immunity and the arms race between plants and their pathogens.
Dissection of the barley 2L1.0 region carrying the 'Laevigatum' quantitative resistance gene to leaf rust using near-isogenic lines (NIL) and subNIL
Marcel, T.C. ; Aghnoum, R. ; Durand, J. ; Varshnev, R.K. ; Niks, R.E. - \ 2007
Molecular Plant-Microbe Interactions 20 (2007)12. - ISSN 0894-0282 - p. 1604 - 1615.
hordeum-vulgare genome - map-based cloning - puccinia-hordei - consensus map - disease-resistance - aflp markers - rflp markers - trait loci - rice - wheat
Partial resistance to leaf rust (Puccinia hordei G. H. Otth) in barley is a quantitative resistance that is not based on hypersensitivity. This resistance hampers haustorium formation, resulting in a long latency period in greenhouse tests. The three most consistent quantitative trait loci (QTL) uncovered in the L94 × 'Vada' mapping population were introgressed by marker-assisted backcrossing into the susceptible L94 background to obtain near-isogenic lines (NIL). We also developed the reciprocal Vada-NIL for the susceptibility alleles of those QTL. The QTL Rphq2 affected latency period of P. hordei more than the QTL Rphq3 and Rphq4. The NIL confirmed the contribution of Rphq2 to partial resistance by prolonging the latency period by 28 h on L94-Rphq2 and shortening the latency period by 23 h on Vada-rphq2. On the basis of flanking restriction fragment length polymorphism-based markers, Rphq2 appeared to be located near the telomeric end of the long arm of chromosome 2H, in a physical region of high recombination, making it the target QTL for map-based cloning. Microscopic observations on the NIL confirmed the nonhypersensitive nature of the resistance conferred by Rphq2. A high-resolution genetic map of the Rphq2 region was constructed using a population of 38 subNIL with overlapping L94 introgressions in Vada background across the region. Rphq2 mapped approximately 2 centimorgans (cM) proximal from the MlLa locus. By bulked segregant analysis and use of synteny with rice, we developed additional markers and fine-mapped Rphq2 to a genetic interval of 0.11 cM that corresponds to a stretch of sequence of, at most, 70 kb in rice. Analysis of this rice sequence revealed predicted genes encoding two proteins with unknown function, retrotransposon proteins, peroxidase proteins, and a protein similar to a mitogen-activated protein kinase kinase kinase (MAP3K). Possible homologs of those peroxidases and MAP3K in barley are candidates for the gene that contributes to partial resistance to P. hordei.