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1.
Western white pine (Pinus monticola Dougl. ex. D. Don., WWP) shows genetic variation in disease resistance to white pine blister rust (Cronartium ribicola). Most plant disease resistance (R) genes encode proteins that belong to a superfamily with nucleotide-binding site domains (NBS) and C-terminal leucine-rich repeats (LRR). In this work a PCR strategy was used to clone R gene analogs (RGAs) from WWP using oligonucleotide primers based on the conserved sequence motifs in the NBS domain of angiosperm NBS-LRR genes. Sixty-seven NBS sequences were cloned from disease-resistant trees. BLAST searches in GenBank revealed that they shared significant identity to well-characterized R genes from angiosperms, including L and M genes from flax, the tobacco N gene and the soybean gene LM6. Sequence alignments revealed that the RGAs from WWP contained the conserved motifs identified in angiosperm NBS domains, especially those motifs specific for TIR-NBS-LRR proteins. Phylogenic analysis of plant R genes and RGAs indicated that all cloned WWP RGAs can be grouped into one major branch together with well-known R proteins carrying a TIR domain, suggesting they belong to the subfamily of TIR-NBS-LRR genes. In one phylogenic tree, WWP RGAs were further subdivided into fourteen clusters with an amino acid sequence identity threshold of 75%. cDNA cloning and RT-PCR analysis with gene-specific primers demonstrated that members of 10 of the 14 RGA classes were expressed in foliage tissues, suggesting that a large and diverse NBS-LRR gene family may be functional in conifers. These results provide evidence for the hypothesis that conifer RGAs share a common origin with R genes from angiosperms, and some of them may play important roles in defense mechanisms that confer disease resistance in western white pine. Ratios of non-synonymous to synonymous nucleotide substitutions (Ka/Ks) in the WWP NBS domains were greater than 1 or close to 1, indicating that diversifying selection and/or neutral selection operate on the NBS domains of the WWP RGA family.Communicated by R. Hagemann 相似文献
2.
Targeted isolation,sequence analysis,and physical mapping of nonTIR NBS-LRR genes in soybean 总被引:2,自引:0,他引:2
Peñuela S Danesh D Young ND 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):261-272
Most cloned plant disease resistance genes (R-genes) code for proteins belonging to the nucleotide binding site (NBS) leucine-rich
repeat (LRR) superfamily. NBS-LRRs can be divided into two classes based on the presence of a TIR domain (Toll and interleukin receptor-like sequence) or a coiled coil motif (nonTIR) in their N-terminus. We used conserved motifs specific
to nonTIR-NBS-LRR sequences in a targeted PCR approach to generate nearly 50 genomic soybean sequences with strong homology
to known resistance gene analogs (RGAs) of the nonTIR class. Phylogenetic analysis classified these sequences into four main
subclasses. A representative clone from each subclass was used for genetic mapping, bacterial artificial chromosome (BAC)
library screening, and construction of RGA-containing BAC contigs. Of the 14 RGAs that could be mapped genetically, 12 localized
to a 25-cM region of soybean linkage group F already known to contain several classical disease resistance loci. A majority
of the genomic region encompassing the RGAs was physically isolated in eight BAC contigs, together spanning more than 1 Mb
of genomic sequence with at least 12 RGA copies. Phylogenetic and sequence analysis, together with genetic and physical mapping,
provided insights into the genome organization and evolution of this large cluster of soybean RGAs.
Received: 8 May 2001 / Accepted: 30 June 2001 相似文献
3.
4.
Sarosh Bejai Ramachandra Niranjan Raj Sathyanarayana Sivaramakrishnan Subramonium Shekar Hunthrike Shetty 《Journal of Phytopathology》2011,159(5):382-389
Sequence analysis of plant disease resistance genes shows similarity among themselves, with the presence of conserved motifs common to the nucleotide‐binding site (NBS). Oligonucleotide degenerate primers designed from the conserved NBS motifs encoded by several plant disease resistance genes were used to amplify resistance gene analogues (RGAs) corresponding to the NBS sequences from the genomic DNA of various plant species. Using specific primers designed from the conserved NBS regions, 22 RGAs were cloned and sequenced from pearl millet (Pennisetum glaucum L. Br.). Phylogenetic analysis of the predicted amino acid sequences grouped the RGAs into nine distinct classes. GenBank database searches with the consensus protein sequences of each of the nine classes revealed their conserved NBS domains and similarity to other known R genes of various crop species. One RGA 213 was mapped onto LG1 and LG7 in the pearl millet linkage map. This is the first report of the isolation and characterization of RGAs from pearl millet, which will facilitate the improvement of marker‐assisted breeding strategies. 相似文献
5.
We amplified resistance gene analogues (RGAs) from the genomic DNA of 10 rice lines having varying degree of resistance to Magnaporthe grisea by using degenerate primers and various RGAs were mapped in silico on different rice chromosomes. The amplified products were grouped into 3–8 restriction fragment length polymorphic classes by using Mbo1 and Alu1 restriction enzymes. Of 98 RGAs obtained in this study, 65 RGA clones showed more than 95% homology with various RGAs sequences present in the GenBank. Phylogenetic analysis of these RGAs formed 11 groups. Using sequence homology approach, RGAs isolated in this study were physically mapped on 23 loci on chromosomes 1, 2, 3, 4, 5, 6, 7, 8, 10, 11 and 12. Twenty RGAs were mapped near to the chromosomal regions containing known genes/QTLs for rice blast, bacterial leaf blight and sheath blight resistance. Thirty‐nine RGA sequences also contained open reading frame representing signature of potential disease resistance genes. 相似文献
6.
Map positions of 47 Arabidopsis sequences with sequence similarity to disease resistance genes 总被引:7,自引:3,他引:4
Miguel A. Botella Mark J. Coleman Douglas E. Hughes Marc T. Nishimura Jonathan D.G. Jones Shauna C. Somerville 《The Plant journal : for cell and molecular biology》1997,12(5):1197-1211
Map positions have been determined for 42 non-redundant Arabidopsis expressed sequence tags (ESTs) showing similarity to disease resistance genes (R-ESTs), and for three Pto-like sequences that were amplified with degenerate primers. Employing a PCR-based strategy, yeast artificial chromosome (YAC) clones containing the EST sequences were identified. Since many YACs have been mapped, the locations of the R-ESTs could be inferred from the map positions of the YACs. R-EST clones that exhibited ambiguous map positions were mapped as either cleavable amplifiable polymorphic sequence (CAPS) or restriction fragment length polymorphism (RFLP) markers using F8 (Ler x Col-0) recombinant inbred (RI) lines. In all cases but two, the R-ESTs and Pto-like sequences mapped to single, unique locations. One R-EST and one Pto-like sequence each mapped to two locations. Thus, a total of 47 loci were identified in this study. Several R-ESTs occur in clusters suggesting that they may have arisen via gene duplication events. Interestingly, several R-ESTs map to regions containing genetically defined disease resistance genes. Thus, this collection of mapped R-ESTs may expedite the isolation of disease resistance genes. As the cDNA sequencing projects have identified an estimated 63% of Arabidopsis genes, a very large number of R-ESTs (~95), and by inference disease resistance genes of the leucine-rich repeat-class probably occur in the Arabidopsis genome. 相似文献
7.
Suren K. Samuelian Angela M. Baldo Jeremy A. Pattison Courtney A. Weber 《Tree Genetics & Genomes》2008,4(4):881-896
Plant R genes confer resistance to pathogens in a gene-for-gene mode. Seventy-five putative resistance gene analogs (RGAs) containing
conserved domains were cloned from Rubus idaeus L. cv. ‘Latham’ using degenerate primers based on RGAs identified in Rosaceae species. The sequences were compared to 195
RGA sequences identified from five Rosaceae family genera. Multiple sequence alignments showed high similarity at multiple
nucleotide-binding site (NBS) motifs with homology to Drosophila Toll and mammalian interleukin-1 receptor (TIR) and non-TIR
RNBSA-A motifs. The TIR sequences clustered separately from the non-TIR sequences with a bootstrap value of 76%. There were
11 clusters each of TIR and non-TIR type sequences of multiple genera with bootstrap values of more than 50%, including nine
with values of more than 75% and seven of more than 90%. Polymorphic sequence characterized amplified region and cleaved amplified
polymorphic sequence markers were developed for nine Rubus RGA sequences with eight placed on a red raspberry genetic linkage map. Phylogenetic analysis indicated four of the mapped
sequences share sequence similarity to groupTIR I, while three others were spread in non-TIR groups. Of the 75 Rubus RGA sequences analyzed, members were placed in five TIR groups and six non-TIR groups. These group classifications closely
matched those in 12 of 13 studies from which these sequences were derived. The analysis of related DNA sequences within plant
families elucidates the evolutionary relationship and process involved in pest resistance development in plants. This information
will aid in the understanding of R genes and their proliferation within plant genomes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
The resistance (R) proteins of the TIR- and non-TIR (or CC-) superfamilies possess a nucleotide binding site (NBS) domain.
Within an R gene, the NBS is the region of highest conservation, suggesting an essential role in triggering R protein activity. We compared
the NBS domain of functional R genes and resistance gene analogs (RGA) amplified from S. caripense genomic DNA via PCR using specific and degenerate primers with its counterpart from other plants. An overall high degree
of sequence conservation was apparent throughout the P-loop, kinase-2 and kinase-3a motifs of NBS fragments from all plants.
Within the non-TIR class of R genes a prominent sub-class similar to the potato R1 gene conferring resistance to late blight, was detected. All non-TIR-R1-like R gene fragments that were sequenced possessed an intact open reading frame, whereas 22% of all non-TIR-non-R1-like fragments
and 59% of all TIR-NBS RGA fragments had an interrupted reading frame or contained transposon-specific sequence. The non-TIR-R1-like
fragments had high similarity to Solanaceae R genes and low similarity to RGAs of other plant species including A. thaliana and the cereals. It is concluded that appearance of the non-TIR-R1-like NBS domain represents a relatively recent evolutionary
development.
Electronic supplementary material Supplementary material is available in the online version of this article at
and is accessible for authorized users. 相似文献
9.
Clément D Lanaud C Sabau X Fouet O Le Cunff L Ruiz E Risterucci AM Glaszmann JC Piffanelli P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(8):1627-1634
We have constructed and validated the first cocoa (Theobroma cacao L.) BAC library, with the aim of developing molecular resources to study the structure and evolution of the genome of this perennial crop. This library contains 36,864 clones with an average insert size of 120 kb, representing approximately ten haploid genome equivalents. It was constructed from the genotype Scavina-6 (Sca-6), a Forastero clone highly resistant to cocoa pathogens and a parent of existing mapping populations. Validation of the BAC library was carried out with a set of 13 genetically-anchored single copy and one duplicated markers. An average of nine BAC clones per probe was identified, giving an initial experimental estimation of the genome coverage represented in the library. Screening of the library with a set of resistance gene analogues (RGAs), previously mapped in cocoa and co-localizing with QTL for resistance to Phytophthora traits, confirmed at the physical level the tight clustering of RGAs in the cocoa genome and provided the first insights into the relationships between genetic and physical distances in the cocoa genome. This library represents an available BAC resource for structural genomic studies or map-based cloning of genes corresponding to important QTLs for agronomic traits such as resistance genes to major cocoa pathogens like Phytophthora spp (palmivora and megakarya), Crinipellis perniciosa and Moniliophthora roreri.Communicated by J.W. Snape 相似文献
10.
Plant disease resistance gene (R gene) and defense response gene encode some conserved motifs. In the present work, a PCR strategy was used to clone resistance
gene analogs (RGAs) and defense gene analogs (DGAs) from Sea-island cotton variety Hai7124 using oligonucleotide primers based
on the nucleotide-binding site (NBS) and serine/threonine kinase (STK) in the R-gene and pathogenesis-related proteins of class 2 (PR2) of defense response gene. 79 NBS sequences, 21 STK sequences and
11 DGAs were cloned from disease-resistance cotton. Phylogenic analysis of 79 NBS-RGAs and NBS-RGAs nucleotide sequences of
cotton already deposited in GenBank identified one new sub-cluster. The deduced amino acid sequences of NBS-RGAs and STK-RGAs
were divided into two distinct groups respectively: Toll/Interleukin-1 receptor (TIR) group and non-TIR group, A group and
B group. The expression of RGAs and DGAs having consecutive open reading frame (ORF) was also investigated and it was found
that 6 NBS-RGAs and 1 STK-RGA were induced, and 1 DGA was up-regulated by infection of Verticillium dahliae strain VD8. 4 TIR-NBS-RGAs and 4 non-TIR-NBS-RGAs were arbitrarily used as probes for Southern-blotting. There existed 2–10
blotted bands. In addition, since three non-TIR-NBS-RGAs have the same hybridization pattern, we conjecture that these three
RGAs form a cluster distribution in the genome. 相似文献
11.
Plant disease resistance gene (R gene) and defense response gene encode some conserved motifs. In the present work, a PCR strategy was used to clone resistance
gene analogs (RGAs) and defense gene analogs (DGAs) from Sea-island cotton variety Hai7124 using oligonucleotide primers based
on the nucleotide-binding site (NBS) and serine/threonine kinase (STK) in the R-gene and pathogenesis-related proteins of class 2 (PR2) of defense response gene. 79 NBS sequences, 21 STK sequences and
11 DGAs were cloned from disease-resistance cotton. Phylogenic analysis of 79 NBS-RGAs and NBS-RGAs nucleotide sequences of
cotton already deposited in GenBank identified one new sub-cluster. The deduced amino acid sequences of NBS-RGAs and STK-RGAs
were divided into two distinct groups respectively: Toll/Interleukin-1 receptor (TIR) group and non-TIR group, A group and
B group. The expression of RGAs and DGAs having consecutive open reading frame (ORF) was also investigated and it was found
that 6 NBS-RGAs and 1 STK-RGA were induced, and 1 DGA was up-regulated by infection of Verticillium dahliae strain VD8. 4 TIR-NBS-RGAs and 4 non-TIR-NBS-RGAs were arbitrarily used as probes for Southern-blotting. There existed 2–10
blotted bands. In addition, since three non-TIR-NBS-RGAs have the same hybridization pattern, we conjecture that these three
RGAs form a cluster distribution in the genome. 相似文献
12.
Isolation and diversity analysis of resistance gene analogues (RGAs) from cultivated and wild strawberries 总被引:7,自引:0,他引:7
Martínez Zamora MG Castagnaro AP Díaz Ricci JC 《Molecular genetics and genomics : MGG》2004,272(4):480-487
Degenerate oligonucleotide primers, designed based on conserved regions of Nucleotide Binding Site (NBS) domains from previously cloned plant resistance genes, were used to isolate Resistance Gene Analogues (RGAs) from wild and cultivated strawberries. Seven distinct families of RGAs of the NBS-LRR type were identified from two related wild species, Fragaria vesca and F. chiloensis, and six different Fragaria × ananassa cultivars. With one exception (GAV-3), the deduced amino acid sequences of strawberry RGAs showed strong similarity to TIR (Toll Interleukin I Receptor)-type R genes from Arabidopsis, tobacco and flax, suggesting the existence of common ancestors. GAV-3 seemed to be more closely related to the non-TIR type. Further studies showed that the recombination level and the ratio of non-synonymous to synonymous substitutions within families were low. These data suggest that NBS-encoding sequences of RGAs in strawberry are subject to a gradual accumulation of mutations leading to purifying selection, rather than to a diversifying process. The present paper is the first report on RGAs in strawberry.Communicated by M.-A. Grandbastien 相似文献
13.
The Pto locus governs resistance to bacterial speck disease in tomato caused by race 0 strains of Pseudomonas syringae pathovar tomato (Pst). Large populations segregating for the Pto locus were generated and genetically characterized. Analysis of the locus has revealed that Pto acts in a semi-dominant manner and cosegegrates with sensitivity to an organophosphorous insecticide, Fenthion, suggesting that Pto may be a complex locus responsible for both phenotypes. We have redefined its map position on chromosome five of the classical genetic map and assigned its position on the molecular map, thus facilitating the alignment of the two genetic maps of the short arm of chromosome five of tomato. Furthermore, we have screened random amplified polymorphic (RAPD) markers for their ability to differentiate near-isogenic lines that differ only with respect to Pto and have identified and mapped seven of these markers. Our results suggest that Pto may be located in a euchromatic region on chromosome five which will be advantageous for the cloning of this locus by one of several molecular strategies. 相似文献
14.
Identification of resistance gene analogs linked to a powdery mildew resistance locus in grapevine 总被引:18,自引:6,他引:12
Donald TM Pellerone F Adam-Blondon AF Bouquet A Thomas MR Dry IB 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):610-618
Oligonucleotide primers, designed to conserved regions of nucleotide binding site (NBS) motifs within previously cloned pathogen
resistance genes, were used to amplify resistance gene analogs (RGAs) from grapevine. Twenty eight unique grapevine RGA sequences
were identified and subdivided into 22 groups on the basis of nucleic acid sequence-identity of approximately 70% or greater.
Representatives from each group were used in a bulked segregant analysis strategy to screen for restriction fragment length
polymorphisms linked to the powdery mildew resistance locus, Run1, introgressed into Vitis vinifera L. from the wild grape species Muscadinia rotundifolia. Three RGA markers were found to be tightly linked to the Run1 locus. Of these markers, two (GLP1–12 and MHD145) cosegregated with the resistance phenotype in 167 progeny tested, whereas
the third marker (MHD98) was mapped to a position 2.4 cM from the Run1 locus. The results demonstrate the usefulness of RGA sequences, when used in combination with bulked segregant analysis,
to rapidly generate markers tightly linked to resistance loci in crop species.
Received: 2 May 2001 / Accepted: 3 August 2001 相似文献
15.
Characterization and linkage mapping of R-gene analogous DNA sequences in pea (Pisum sativum L.) 总被引:2,自引:0,他引:2
G. M. Timmerman-Vaughan T. J. Frew N. F. Weeden 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(1-2):241-247
Pea (Pisum sativum L.) sequences that are analogous to the conserved nucleotide binding site (NBS) domain found in a number of plant disease
resistance genes (R-genes) were cloned. Using redundant oligonucleotide primers and the polymerase chain reaction (PCR), we
amplified nine pea sequences and characterised their sequences. The pea R-gene analog (RGA)- deduced amino acid sequences
demonstrated significant sequence similarity with known R-gene sequences lodged in public databases. The genomic locations
of eight of the pea RGAs were determined by linkage mapping. The eight RGAs identified ten loci that mapped to six linkage
groups. In addition, the genomic organization of the RGAs was inferred. Both single-copy and multicopy sequence families were
present among the RGAs, and the multicopy families occurred most often as tightly linked clusters of related sequences. Intraspecific
copy number variability was observed in three of the RGA sequence families, suggesting that these sequence families are evolving
rapidly. The genomic locations of the pea RGAs were compared with the locations of known pea R-genes and sym genes involved in the pea-rhizobia symbiosis. Two pea RGAs mapped in the genomic region containing a pea R-gene, Fw, and four pea RGAs mapped in regions of the genome containing sym genes.
Received: 4 August 1999 / Accepted: 11 November 1999 相似文献
16.
Resistance gene analogues from rice: cloning, sequencing and mapping 总被引:18,自引:0,他引:18
R. Mago S. Nair M. Mohan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,99(1-2):50-57
Degenerate oligonucleotide primers were designed on the basis of nucleotide-binding-site (NBS) motifs conserved between resistance
genes of Arabidopsis, flax and tobacco and subsequently used as PCR primers to amplify resistance gene analogues (RGA) in rice. Primers amplified
a major band of approximately 500 bp. Restriction analysis of the amplified product revealed that the band was made up of
several different fragments. Many of these fragments were cloned. Sixty different cloned fragments were analysed and assigned
to 14 categories based on Southern blot analysis. Fourteen clones, each representing one of the 14 categories of RGAs were
mapped onto the rice genetic map using a Nipponbare ( japonica)בKasalath’ (indica) mapping population consisting of 186 F2 lines. Of the 14 clones representing each class 12 could be mapped onto five different chromosomes of rice with a major cluster
of 8 RGAs on chromosome 11. Our results indicate that it is possible to use sequence homology from conserved motifs of known
resistance genes to amplify candidate resistance genes from diverse plant taxa.
Received: 23 September 1998 / Accepted: 28 November 1998 相似文献
17.
番茄Pto基因是一类可以编码丝氨酸/苏氨酸激酶(STK)序列的广谱抗性候选基因,其序列克隆与鉴定为深入了解番茄的抗病机制奠定了基础.在该研究中,一对依据Pto基因的保守序列设计的简并引物被用来扩增巴西橡胶中Pto基因抗病同源序列,扩增得到了一个约550 bp的基因片段,其随后被克隆并测序.序列分析发现,其中的7个抗病同源序列与Pto基因高度同源(BLASTX E value <3e-53),所以其被认为是Pto基因抗病同源序列(Pto-RGCs).通过巴西橡胶的Pto-RGCs多序列比对表明,这些序列包含了多个STKs保守的次级结构域.此外,系统发育分析也表明,巴西橡胶的Pto-RGCs属于Pto基因同源的R基因.该研究结果中Pto-RGCs可为巴西橡胶抗病的发展提供一个有效的基因资源. 相似文献
18.
Cloning and characterisation of a family of disease resistance gene analogs from wheat and barley 总被引:7,自引:0,他引:7
S. Seah K. Sivasithamparam A. Karakousis E. S. Lagudah 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(5-6):937-945
The most common class of plant disease resistance (R) genes cloned so far belong to the NBS-LRR group which contain nucleotide-binding
sites (NBS) and a leucine-rich repeat (LRR). Specific primer sequences derived from a previously isolated NBS-LRR sequence
at the Cre3 locus, which confers resistance to cereal cyst nematode (CCN) in wheat (Triticum aestivum L.) were used in isolating a family of resistance gene analogs (RGA) through a polymerase chain reaction (PCR) cloning approach.
The cloning, analysis and genetic mapping of a family of RGAs from wheat (cv ‘Chinese Spring’) and barley (Hordeum vulgare L. cvs ‘Chebec’ and ‘Harrington’) are presented. The wheat and barley RGAs contain other conserved motifs present in known
R genes from other plants and share between 55–99% amino acid sequence identity to the NBS-LRR sequence at the Cre3 locus. Phylogenetic analysis of the RGAs with other cloned R genes and RGAs from various plant species indicate that they
belong to a superfamily of NBS-containing genes. Two of the barley derived RGAs were mapped onto loci on chromosomes 2H (2),
5H (7) and 7H (1) using barley doubled haploid (DH) mapping populations. Some of these loci identified are associated with
regions carrying resistance to CCN and corn leaf aphid.
Received: 6 January 1998 / Accepted: 1 April 1998 相似文献
19.
Nedim Mutlu Phillip N. Miklas Dermot P. Coyne 《Molecular breeding : new strategies in plant improvement》2006,17(2):127-135
Resistance (R) genes containing nucleotide-binding site (NBS)-leucine rich repeats (LRR) are the most prevalent types of R
gene in plants. The objective of this study was to develop PCR-based R-gene analog polymorphism (RGAP) markers for common
bean (Phaseolus vulgaris L). Twenty degenerate primers were designed from the conserved kinase-1a (GVGKTT) and hydrophobic domains (GLPLAL) of known
NBS-LRR type R-genes and from EST databases. Sixty-six of the 100 primer combinations tested yielded polymorphism. Thirty-two
RGAP markers were mapped in the BAT 93/Jalo EEP558 core mapping population for common bean. The markers mapped to 10 of 11
linkage groups with a strong tendency for clustering. In addition, the RGAP markers co-located, on six linkage groups, with
15 resistance gene analogs (RGAs) that were previously mapped in other populations of common bean. The distance between the
priming sites in NBS-LRR type R-genes is around 500 bp. Of the 32 RGAP markers, 19 had sizes larger and 13 less than 500 bp.
RGAP markers mapped close to known R-genes on B11, and to QTLs for resistance on B1, B2, B6, B7, B8, B10, and B11. RGAP appears
to provide a useful marker technique for tagging and mapping R-genes in segregating common bean populations, discovery of
candidate genes underlying resistance QTL, and future cloning of R-genes in common bean. 相似文献
20.
Vishnu Sukumari Nath Muthukrishnan Senthil Muthulekshmi Lajapathy Jeeva Raj Shekar Misra Syamala Swayamvaran Veena 《Archives Of Phytopathology And Plant Protection》2013,46(7):803-812
Primers based on the conserved motifs were used to isolate nucleotide-binding sites (NBS) type sequences in taro (Colocasia esculenta). Cloning and sequencing identified three taro NBS-type sequences called resistance gene analogues (RGAs) that depicted similarity to other cloned RGA sequences. The deduced amino acid sequences of the RGAs detected the presence of conserved domains, viz. P-loop, categorising them with the NBS–leucine-rich repeat class gene family. Phylogenetic characterisation of the taro RGAs along with RGAs of other plant species grouped them with the non-toll interleukin receptor subclasses of the NBS sequences. The isolation and characterisation of taro RGAs have been reported for the first time in this study. This will provide a starting point towards characterisation of candidate resistance genes in taro and can act as a reference guide for future studies. 相似文献