Identification of Regions in Alleles of the Flax Rust Resistance Gene L That Determine Differences in Gene-for-Gene Specificity

Ellis, Jeffrey G.; Lawrence, Gregory J.; Luck, Jo; Dodds, Peter N.

doi:10.2307/3870876

Cited by 121 publications

(209 citation statements)

References 0 publications

Supporting

Mentioning

199

Contrasting

Unclassified

Order By: Relevance

“…Many of the structural and sequence differences among the L alleles are confined to the LRR coding region, indicating involvement of the LRR domain in ligand specificity 36 . Additionally, substitution of the L2 LRR domain for the LRR domain of the L6 or L10 isoform results in L2 pathogen specificity 36 . However, some alleles with different pathogen specificity contain identical LRR domains, suggesting that sequences outside the LRR domain influence ligand specificity.…”

Section: The Lrr As An Effector-binding Domainmentioning

confidence: 99%

“…However, some alleles with different pathogen specificity contain identical LRR domains, suggesting that sequences outside the LRR domain influence ligand specificity. Likewise, some chimeric L molecules have demonstrated previously unknown specificities, also suggesting that multiple domains contribute to pathogen-recognition specificity 36,37 .…”

Section: The Lrr As An Effector-binding Domainmentioning

confidence: 99%

See 1 more Smart Citation

Plant NBS-LRR proteins in pathogen sensing and host defense

2006

View full text Add to dashboard Cite

Plant proteins belonging to the nucleotide-binding site-leucine-rich repeat (NBS-LRR) family are used for pathogen detection. Like the mammalian Nod-LRR protein 'sensors' that detect intracellular conserved pathogen-associated molecular patterns, plant NBS-LRR proteins detect pathogen-associated proteins, most often the effector molecules of pathogens responsible for virulence. Many virulence proteins are detected indirectly by plant NBS-LRR proteins from modifications the virulence proteins inflict on host target proteins. However, some NBS-LRR proteins directly bind pathogen proteins. Association with either a modified host protein or a pathogen protein leads to conformational changes in the amino-terminal and LRR domains of plant NBS-LRR proteins. Such conformational alterations are thought to promote the exchange of ADP for ATP by the NBS domain, which activates 'downstream' signaling, by an unknown mechanism, leading to pathogen resistance.Plants lack the adaptive immunity that vertebrates rely on to respond to pathogens. To successfully detect and ward off pathogens, plants must rely solely on genes stably encoded in the genome. Although the exact mechanisms of pathogen detection differ, plants, like animals, use two distinct defense 'systems' to recognize and respond to pathogen challenge 1 . Pathogen-associated molecular patterns (PAMPs), such as bacterial flagellin, lipopolysaccharides and fungal-oomycete cellulose-binding elicitor proteins, are recognized by plant transmembrane receptors that activate basal defense, a first line of defense against pathogens that is reminiscent of innate immunity in vertebrates 2, 3. In both plants and animals, it is hypothesized that a biological 'arms race' is occurring, in which pathogens have acquired mechanisms to evade PAMP-triggered immunity by evolving effector molecules that modify the state of the host cell, thereby bypassing or disrupting the first line of defense. Plant evolution has countered with proteins that detect specific effector molecules, a mechanism called 'effector-triggered immunity'1 that amounts to a second line of defense. Plant effector-triggered immunity is more akin to mammalian adaptive immunity in that pathogen effectors, rather than conserved elements such as PAMPs, are specifically recognized. However, unlike the situation in mammalian adaptive immunity, the plant host specificity determinants of effector-triggered immunity are encoded in every cell of an organism.The genes encoding the specificity determinants of effector-triggered immunity are known as resistance (R) genes. Most R genes encode proteins that contain a nucleotide-binding site (NBS) and leucine-rich repeats (LRRs). NBS-LRR proteins are involved in the recognition of specialized pathogen effectors (also called avirulence (Avr) proteins) that are thought to provide virulence function in the absence of the cognate R gene 1 . NBS-LRR proteins are also important in animal innate immune systems; however, in animals they seem to be involved in PAMP recognition rather th...

show abstract

Section: The Lrr As An Effector-binding Domainmentioning

confidence: 99%

Section: The Lrr As An Effector-binding Domainmentioning

confidence: 99%

Plant NBS-LRR proteins in pathogen sensing and host defense

2006

View full text Add to dashboard Cite

show abstract

“…In each LRR, a region of the consensus sequence (xxLxLxx) is predicted to form a ␤-strand/ ␤-turn structure in which the variable residues (x) are exposed to the solvent and determine the specificity of the interaction. This region of the LRR is subjected to diversifying selection in plant resistance genes (McDowell et al, 1998;Meyers et al, 1998;Ellis et al, 1999;Van der Hoorn et al, 2001). The observation that among different LRXs, the solvent-exposed amino acids are well conserved or even identical (AtLRX3/4 and AtLRX6/7) suggests that the LRX proteins interact with very similar or identical ligands.…”

mentioning

confidence: 99%

Whole-Genome Comparison of Leucine-Rich Repeat Extensins in Arabidopsis and Rice. A Conserved Family of Cell Wall Proteins Form a Vegetative and a Reproductive Clade,

et al. 2003

View full text Add to dashboard Cite

We have searched the Arabidopsis and rice (Oryza sativa) genomes for homologs of LRX1, an Arabidopsis gene encoding a novel type of cell wall protein containing a leucine-rich repeat (LRR) and an extensin domain. Eleven and eight LRX (LRR/EXTENSIN) genes have been identified in these two plant species, respectively. The LRX gene family encodes proteins characterized by a short N-terminal domain, a domain with 10 LRRs, a cysteine-rich motif, and a variable C-terminal extensin-like domain. Phylogenetic analysis performed on the conserved domains indicates the existence of two major clades of LRX proteins that arose before the eudicot/monocot divergence and then diversified independently in each lineage. In Arabidopsis, gene expression studies by northern hybridization and promoter::uidA fusions showed that the two phylogenetic clades represent a specialization into "reproductive" and "vegetative" LRXs. The four Arabidopsis genes of the "reproductive" clade are specifically expressed in pollen, whereas the seven "vegetative" genes are predominantly expressed in various sporophytic tissues. This separation into two expression classes is also supported by previous studies on maize (Zea mays) and tomato (Lycopersicon esculentum) LRX homologs and by information on available rice ESTs. The strong conservation of the amino acids responsible for the putative recognition specificity of the LRR domain throughout the family suggests that the LRX proteins interact with similar ligands.With the completion of the Arabidopsis genome sequence, it became clear that many Arabidopsis genes are members of multigene families. Although this had already been suggested by the analysis of expressed sequence tag (EST) databases and by classical gene searches, the availability of the full gene set of a plant provides the unique opportunity to get a complete inventory of all the members of a gene family. Among the 25,500 genes predicted in the Arabidopsis genome, 65% are members of a multigene family and 37% belong to families of more than five members (Arabidopsis Genome Initiative, 2000). Although the predicted total gene number of Arabidopsis is significantly larger than that of other sequenced multicellular eukaryotes such as Caenorhabditis elegans (19,000; C. elegans Sequencing Consortium, 1998) or Drosophila melanogaster (13,600; Adams et al., 2000), the absolute number of gene families and singletons (11,601 in Arabidopsis) is comparable in all these organisms (Arabidopsis Genome Initiative, 2000). This indicates that frequent gene duplications and consequently large gene families are a distinctive feature of the Arabidopsis genome, and possibly of all plant genomes. With the recent publication of a high-quality draft from two different subspecies, rice (Oryza sativa) is the second plant whose genome can be comprehensively investigated. Depending on the stringency applied in gene prediction, the rice genome contains between 32,277 and 61,668 genes (Goff et al., 2002;Yu et al., 2002). With 77% of the genes distributed in about 15,000 m...

show abstract

“…De fato, em vários sistemas planta-patógeno, a variação da sequência na região LRR tem mostrado ser responsável por diferentes especificidades de reconhecimento ou de resistência Thomas et al, 1997;Botella et al, 1998;Wang et al, 1998;Ellis et al, 1999).…”

Section: Resultsunclassified

Marcadores moleculares derivados de sequências expressas do genoma café potencialmente envolvidas na resistência à ferrugem

Alvarenga

Caixeta

Hufnagel

et al. 2011

Pesq. agropec. bras.

View full text Add to dashboard Cite

Resumo -O objetivo deste trabalho foi identificar marcadores moleculares relacionados à resistência do cafeeiro (Coffea arabica) à ferrugem (Hemileia vastatrix). Foram identificadas sequências de DNA potencialmente envolvidas na resistência do cafeeiro a doenças, por meio de análise "in silico", a partir das informações geradas pelo Projeto Brasileiro do Genoma Café. A partir das sequências mineradas, foram desenhados 59 pares de iniciadores para amplificá-las. Os 59 iniciadores foram testados em 12 cafeeiros resistentes e 12 susceptíveis a H. vastatrix. Vinte e sete iniciadores resultaram em bandas únicas e bem definidas, enquanto um deles amplificou fragmento de DNA em todos os cafeeiros resistentes, mas não nos suscetíveis. Esse marcador molecular polimórfico amplificou uma região do DNA que corresponde a uma janela aberta de leitura parcial do genoma de C. arabica que codifica uma proteína de resistência a doenças. O marcador CARF 005 é capaz de diferenciar os cafeeiros analisados em resistentes e susceptíveis a H. vastatrix.Termos para indexação: Coffea arabica, Hemileia vastatrix, bioinformática, EST-PCR, genes de resistência, mineração de dados. Molecular markers from coffee genome expressed sequences potentially involved in resistance to rustAbstract -The objective of this work was to identify molecular markers related to the resistance of coffee (Coffea arabica) to rust (Hemileia vastatrix). DNA sequences potentially involved in coffee disease resistance were identified, using "in silico" analysis, from data obtained by the Brazilian coffee genome project. After data mining, 59 primer pairs were designed to amplify the sequences identified. The 59 primers were tested on 12 resistant and 12 susceptible coffee plants to H. vastatrix. Twenty-seven primers resulted in unique and well-defined bands, while one of these amplified a DNA fragment in all resistant plants, but not in the susceptible ones. This polymorphic molecular marker amplified a region of DNA that corresponds to a partial open reading frame of C. arabica genome that encodes a disease resistance protein. The marker CARF 005 can be used to differentiate between resistant and susceptible coffee plants to H. vastatrix.

show abstract

Identification of Regions in Alleles of the Flax Rust Resistance Gene L That Determine Differences in Gene-for-Gene Specificity

Cited by 121 publications

References 0 publications

Plant NBS-LRR proteins in pathogen sensing and host defense

Plant NBS-LRR proteins in pathogen sensing and host defense

Whole-Genome Comparison of Leucine-Rich Repeat Extensins in Arabidopsis and Rice. A Conserved Family of Cell Wall Proteins Form a Vegetative and a Reproductive Clade,

Marcadores moleculares derivados de sequências expressas do genoma café potencialmente envolvidas na resistência à ferrugem

Contact Info

Product

Resources

About