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1.
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
2.
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
3.
The majority of known plant resistance genes encode proteins with conserved nucleotide-binding sites and leucine-rich repeats (NBS-LRR). Degenerate primers based on conserved NBS-LRR motifs were used to amplify analogues of resistance genes from the dicot sugar beet. Along with a cDNA library screen, the PCR screen identified 27 genomic and 12 expressed NBS-LRR RGAs (nlRGAs) sugar beet clones. The clones were classified into three subfamilies based on nucleotide sequence identity. Sequence analyses suggested that point mutations, such as nucleotide substitutions and insertion/deletions, are probably the primary source of diversity of sugar beet nlRGAs. A phylogenetic analysis revealed an ancestral relationship among sugar beet nlRGAs and resistance genes from various angiosperm species. One group appeared to share the same common ancestor as Prf, Rx, RPP8, and Mi, whereas the second group originated from the ancestral gene from which 12C1, Xa1, and Cre3 arose. The predicted protein products of the nlRGAs isolated in this study are all members of the non-TIR-type resistance gene subfamily and share strong sequence and structural similarities with non-TIR-type resistance proteins. No representatives of the TIR-type RGAs were detected either by PCR amplification using TIR type-specific primers or by in silico screening of more than 16,000 sugar beet ESTs. These findings suggest that TIR type of RGAs is absent from the sugar beet genome. The possible evolutionary loss of TIR type RGAs in the sugar beet is discussed.
These authors (Yanyan Tian, Longjiang Fan) contributed equally to this work. 相似文献
4.
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
5.
Zhou T Wang Y Chen JQ Araki H Jing Z Jiang K Shen J Tian D 《Molecular genetics and genomics : MGG》2004,271(4):402-415
A complete set of candidate disease resistance ( R) genes encoding nucleotide-binding sites (NBSs) was identified in the genome sequence of japonica rice ( Oryza sativa L. var. Nipponbare). These putative R genes were characterized with respect to structural diversity, phylogenetic relationships and chromosomal distribution, and compared with those in Arabidopsis thaliana. We found 535 NBS-coding sequences, including 480 non-TIR (Toll/IL-1 receptor) NBS-LRR (Leucine Rich Repeat) genes. TIR NBS-LRR genes, which are common in A. thaliana, have not been identified in the rice genome. The number of non-TIR NBS-LRR genes in rice is 8.7 times higher than that in A. thaliana, and they account for about 1% of all of predicted ORFs in the rice genome. Some 76% of the NBS genes were located in 44 gene clusters or in 57 tandem arrays, and 16 apparent gene duplications were detected in these regions. Phylogenetic analyses based both NBS and N-terminal regions classified the genes into about 200 groups, but no deep clades were detected, in contrast to the two distinct clusters found in A. thaliana. The structural and genetic diversity that exists among NBS-LRR proteins in rice is remarkable, and suggests that diversifying selection has played an important role in the evolution of R genes in this agronomically important species. (Supplemental material is available online at .)Communicated by R. HagemannThe first three authors contributed equally to this work 相似文献
6.
To understand the roles of two well known tumour suppressor genes.l(2)gl andl(2)gd in normal imaginal disc development inDrosophila, we have initiated a study to examine effect of mulations of these genes on the expression of genes involved in the patterning
of the imaginal discs. In this study we show that the expression ofwingless, theDrosophila orthologue of the mammalian oncogeneWnt, is affected in the imaginal discs ofl(2)gl
4
andl(2)gd
1
mutant individuals. In the tumourous wing imaginal discs froml(2)gl mutant larvae, the pattern ofwingless expression was progressively disrupted with an increase in the area of expression, Tumourous wing imaginal discs froml(2)gd homozygous individuals exhibited progressive broadening and extension of the wingless expressing domains. We suggest thatl(2)gl andl(2)gd might be involved in regulating post embryonic expression ofWingless. 相似文献
7.
Wenkai X Mingliang X Jiuren Z Fengge W Jiansheng L Jingrui D 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,113(1):63-72
Conserved domains or motifs shared by most known resistance (R) genes have been extensively exploited to identify unknown R-gene analogs (RGAs). In an attempt to isolate all potential RGAs from the maize genome, we adopted the following three methods: modified amplified fragment length polymorphism (AFLP), modified rapid amplification of cDNA ends (RACE), and data mining. The first two methods involved PCR-based isolations of RGAs with degenerate primers designed based on the conserved NBS domain; while the third method involved mining of RGAs from the maize EST database using full-length R-gene sequences. A total of 23 and 12 RGAs were obtained from the modified AFLP and RACE methods, respectively; while, as many as 109 unigenes and 77 singletons with high homology to known R-genes were recovered via data-mining. Moreover, R-gene-like ESTs (or RGAs) identified from the data-mining method could cover all RACE-derived RGAs and nearly half AFLP-derived RGAs. Totally, the three methods resulted in 199 non-redundant RGAs. Of them, at least 186 were derived from putative expressed R-genes. RGA-tagged markers were developed for 55 unique RGAs, including 16 STS and 39 CAPS markers. 相似文献
8.
Characterization and mapping of NBS-LRR resistance gene analogs in apricot (Prunus armeniaca L.) 总被引:2,自引:0,他引:2
Soriano JM Vilanova S Romero C Llácer G Badenes ML 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(5):980-989
Genomic DNA sequences sharing homology with the NBS-LRR (nucleotide binding site-leucine-rich repeat) resistance genes were isolated and cloned from apricot (Prunus armeniaca L.) using a PCR approach with degenerate primers designed from conserved regions of the NBS domain. Restriction digestion and sequence analyses of the amplified fragments led to the identification of 43 unique amino acid sequences grouped into six families of resistance gene analogs (RGAs). All of the RGAs identified belong to the Toll-Interleukin receptor (TIR) group of the plant disease resistance genes (R-genes). RGA-specific primers based on non-conserved regions of the NBS domain were developed from the consensus sequences of each RGA family. These primers were used to develop amplified fragment length polymorphism (AFLP)-RGA markers by means of an AFLP-modified procedure where one standard primer is substituted by an RGA-specific primer. Using this method, 27 polymorphic markers, six of which shared homology with the TIR class of the NBS-LRR R-genes, were obtained from 17 different primer combinations. Of these 27 markers, 16 mapped in an apricot genetic map previously constructed from the self-pollination of the cultivar Lito. The development of AFLP-RGA markers may prove to be useful for marker-assisted selection and map-based cloning of R-genes in apricot. 相似文献
9.
Recombination rate data are presented for three populations of grape based on framework genetic linkage maps developed with
simple-sequence repeat markers. These linkage maps were constructed from different Vitis species and represent three genetic backgrounds. The first population is pure Vitis vinifera, derived from a cross of the European cultivars Riesling and Cabernet Sauvignon. The second is an interspecific cross between
two commercially used rootstock cultivars of different North American Vitis species parentage, Ramsey (Vitis champinii) and Riparia Gloire (Vitis riparia). The third population, D8909-15 (Vitis rupestris × (Vitis arizonica/Vitis girdiana form)) × F8909-17 (V. rupestris × (V. arizonica/Vitis candicans form)), is an F1 from two half-sibs. Genome-wide and chromosome-wide recombination rates varied across the three populations
and among the six Vitis parents. Global recombination rates in the parents of the third F1 population, with a complex Vitis background, were significantly reduced. In the first and third populations, the recombination rate was significantly greater
in the male parent. Specific genome locations with frequent heterogeneity in recombination were identified, suggesting that
recombination rates are not equal across the Vitis genome. The identification of regions with suppressed or high recombination will aid grape breeders and geneticists who rely
on recombination events to introgress disease resistance genes from the genomes of wild Vitis species, develop fine-scale genetic maps, and clone disease resistance genes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Cloning of resistance gene analogs located on the alien chromosome in an addition line of wheat-Thinopyrum intermedium 总被引:2,自引:0,他引:2
Jiang SM Hu J Yin WB Chen YH Wang RR Hu ZM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(5):923-931
Homology-based gene/gene-analog cloning method has been extensively applied in isolation of RGAs (resistance gene analogs)
in various plant species. However, serious interference of sequences on homoeologous chromosomes in polyploidy species usually
occurred when cloning RGAs in a specific chromosome. In this research, the techniques of chromosome microdissection combined
with homology-based cloning were used to clone RGAs from a specific chromosome of Wheat-Thinopyrum alien addition line TAi-27,
which was derived from common wheat and Thinopyrum
intermedium with a pair of chromosomes from Th. intermedium. The alien chromosomes carry genes for resistance to BYDV. The alien chromosome in TAi-27 was isolated by a glass needle
and digested with proteinase K. The DNA of the alien chromosome was amplified by two rounds of Sau3A linker adaptor-mediated
PCR. RGAs were amplified by PCR with the degenerated primers designed based on conserved domains of published resistance genes
(R genes) by using the alien chromosome DNA, genomic DNA and cDNA of Th. intermedium, TAi-27 and 3B-2 (a parent of TAi-27) as templates. A total of seven RGAs were obtained and sequenced. Of which, a constitutively
expressed single-copy NBS-LRR type RGA ACR3 was amplified from the dissected alien chromosome of TAi-27, TcDR2 and TcDR3 were
from cDNA of Th. intermedium, AcDR3 was from cDNA of TAi-27, FcDR2 was from cDNA of 3B-2, AR2 was from genomic DNA of TAi-27 and TR2 was from genomic
DNA of Th. intermedium. Sequence homology analyses showed that the above RGAs were highly homologous with known resistance genes or resistance gene
analogs and belonged to NBS-LRR type of R genes. ACR3 was recovered by PCR from genomic DNA and cDNA of Th. intermedium and TAi-27, but not from 3B-2. Southern hybridization using the digested genomic DNA of Th. intermedium, TAi-27 and 3B-2 as the template and ACR3 as the probe showed that there is only one copy of ACR3 in the genome of Th. intermedium and TAi-27, but it is absent in 3B-2. The ACR3 could be used as a specific probe of the R gene on the alien chromosome of
TAi-27. Results of Northern hybridization suggested that ACR3 was constitutively expressed in Th. intermedium and TAi-27, but not 3B-2, and expressed higher in leaves than in roots. This research demonstrated a new way to clone RGAs
located on a specific chromosome. The information reported here should be useful to understand the resistance mechanism of,
and to clone resistant genes from, the alien chromosome in TAi-27. 相似文献
11.
Microsatellite repeats in grapevine reveal DNA polymorphisms when analysed as sequence-tagged sites (STSs) 总被引:14,自引:0,他引:14
M. R. Thomas N. S. Scott 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,86(8):985-990
Microsatellite repeat sequences were investigated as sequenced-tagged site (STS) DNA markers to determine the potential for genetic analysis of the grapevine genome. The PCR-generated markers detect codominant alleles at a single locus or site in the genome. The marker type is very informative detecting high heterozygosity (69%–88%) within individual grapevine cultivars and high genetic variation between cultivars, making it a useful marker type for plant genome mapping and genome typing. For five loci a screening of 26 V. vinifera cultivars found 13, 12, 8, 5, and 4 different length alleles respectively with some alleles more common than others. The genomic DNA sequences surrounding microsatellite sequences were conserved within the genus permitting STS primers to amplify STSs from other Vitis species. These Vitis species were found to have some unique alleles not present in V. vinifera. 相似文献
12.
Xin Xu N. Hayashi C. T. Wang H. Kato T. Fujimura S. Kawasaki 《Molecular breeding : new strategies in plant improvement》2008,22(2):289-299
The Pik-h gene in rice confers resistance to several races of rice blast fungus (Magnaporthe oryzae), and has been classified as a member of the Pik cluster, one of the most resistance (R) gene-dense regions in the rice genome. However, the loss of a key mutant isolate has long made it difficult to differentiate
Pik-h from other Pik group genes especially from Pik-m. We identified new natural isolates enabling the differentiation between Pik-h and Pik-m genes, and first confirmed the authenticity of the International Rice Research Institute (IRRI) “monogenic” line IRBLkh-K3,
and then fine-mapped the Pik-h gene in the Pik cluster. Using 701 susceptible individuals among 3,060 siblings from a cross of IRBLkh-K3×CO39, the Pik-h region was delimited to 270 kb, the narrowest interval among the Pik group genes reported to date, in the cv. Nipponbare genome. Annotation of this genome region first revealed 6 NBS-LRR type
R-gene analogs (RGAs), clustered within the central 120 kb, as possible counterparts of Pik-h and 6 other Pik group R genes. Interestingly, the Pik-h region and the cluster of RGAs were shown to be located 130 kb and 230 kb apart from Xa4 and Xa2 bacterial blight resistance genes, respectively, once classified as belonging to the Pik cluster. The closest recombination events were limited to the margins of the Pik-h region, and recombination was suppressed in the core interval with the RGA cluster. This fine-mapping, performed in a short
time using an HEGS system, will facilitate utilization of the cluster’s genetic resources and help to elucidate the mechanism
of evolution of R-genes. The presence of natural isolates also confirmed that evolution of Pik-h corresponds to pathogen evolution. 相似文献
13.
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
14.
We determined the parental species ofYoungia koidzumiana (a natural interspecific hybrid) using PCR and arbitrary 10-mer primers to generate random amplified polymorphic DNA (RAPD)
markers. These markers, generated by three primers, were sufficient to distinguishYoungia sonchifolia, Youngia denticulata, Youngia chelidoniifolia, andY. koidzumiana. The electrophoresis profiles of the amplified products from each of the four species were then compared. Three primers produced
a total of 42 scorable markers; nine were specific markers forY. denticulata andY. chelidoni-ifolia. The length of the amplified DNA fragments ranged from 370 to 2500 b p. The three primers revealed polymorphic bands, which
were indicators of the parental species ofY. koidzumiana. These bands showed a combination of specific profiles forY. denticulata andY. chelidoniifolia. Our results also were comparable to the data obtained for flowering times, floret numbers, and chromosome numbers of the
four species. Therefore, we suggest thatY. koidzumiana is a hybrid betweenY. denticulata andY. chelidoniifolia}, and that RAPD markers are well suited for assessing the origins of plant species. 相似文献
15.
The genes encoding the nucleotide-binding site (NBS) and leucine-rich repeat (LRR) motifs constitute a large gene family in plants and have attracted much interest, because most of the plant disease-resistance genes that have been cloned are from this gene family. In this study, degenerate oligonucleotide primers, designed on the basis of conserved regions of the NBS domains from known plant resistance genes, were used to isolate resistance gene analogs (RGAs) from cultivated and wild eggplants, i.e., S. melongena, S. aethiopicum gr. Gilo, S. linnaeanum, S. integrifolium, S. sisymbriifolium, and S. khasianum. Sequence analysis indicated that the cloned eggplant RGAs belong to the non-TIR–NBS–LRR type, which are very similar to the R genes or the RGAs identified in other plant species, especially Solanaceae plants, suggesting the existence of common ancestors. Wide genetic diversity of eggplant RGAs was observed both in interspecific and intraspecific sequences, and eight distinct families of eggplant RGAs were identified. Further studies revealed a high average ratio of synonymous to non-synonymous substitution and a low level of recombination. These results suggest that NBS-encoding sequences of RGAs in cultivated and wild eggplants are subject to gradual accumulation of mutations leading to purifying selection. This is the first report of NBS–LRR class RGAs in eggplants. 相似文献
16.
Jinxia Shi Seon-In Yeom Won-Hee Kang Min-Kyu Park Doil Choi Jin-Kyung Kwon Jung-Heon Han Heung-Ryul Lee Byung-Dong Kim Byoung-Cheorl Kang 《Plant biotechnology reports》2011,5(4):331-344
The well-conserved NBS domain of resistance (R) genes cloned from many plants allows the use of a PCR-based approach to isolate resistance gene analogs (RGAs). In this
study, we isolated an RGA (CapRGC) from Capsicum annuum “CM334” using a PCR-based approach. This sequence encodes a protein with very high similarity to Rx genes, the Potato Virus X (PVX) R genes from potato. An evolutionary analysis of the CapRGC gene and its homologs retrieved by an extensive search of a Solanaceae database provided evidence that Rx-like genes (eight ESTs or genes that show very high similarity to Rx) appear to have diverged from R1 [an NBS-LRR R gene against late blight (Phytophthora infestans) from potato]-like genes. Structural comparison of the NBS domains of all the homologs in Solanaceae revealed that one novel
motif, 14, is specific to the Rx-like genes, and also indicated that several other novel motifs are characteristic of the R1-like genes. Our results suggest that Rx-like genes are ancient but conserved. Furthermore, the novel conserved motifs can provide a basis for biochemical structural–function
analysis and be used for degenerate primer design for the isolation of Rx-like sequences in other plant species. Comparative mapping study revealed that the position of CapRGC is syntenic to the locations of Rx and its homolog genes in the potato and tomato, but cosegregation analysis showed that CapRGC may not be the R gene against PVX in pepper. Our results confirm previous observations that the specificity of R genes is not conserved, while the structure and function of R genes are conserved. It appears that CapRGC may function as a resistance gene to another pathogen, such as the nematode to which the structure of CapRGC is most similar. 相似文献
17.
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
18.
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
19.
Massoma Ali-Ahmad Harrison G. Hughes Farida Safadi 《In vitro cellular & developmental biology. Plant》1998,34(1):1-7
Summary Scanning electron microscopy, light microscopy, and gravimetric analysis was used to evaluate stomatal function, epicuticular
wax, and the stem-root transition region of grape (Vitis sp. ‘Valiant’) plantlets grownin vitro, polyethylene glycoltreatedin vitro, and greenhouse-grown plants. Scanning electron microscopic studies of leaf surfaces ofin vitro-grown plants showed widely open stomata as compared to leaf stomata of polyethylene glycol-treatedin vitro-cultured and greenhouse-grown plants. Ultrastructurally, leaf epicuticular wax ofin vitro plants was less dense than in their polyethylene-treated and greenhouse counterparts. Quantitatively,in vitro-grown plants had reduced epicuticular was as compared to polyethylene glycol-treated and greenhouse-grown plants. Light microscopic
studies showed no obvious differences in the vascular connections in the stem-root transition region ofin vitro-cultured, polyethylene glycol-treatedin vitro-cultured, and greenhouse-grown plants. It is therefore likely that the rapid wilting and desiccation observed after transplantingin vitro grape plantlets is due to their defective stomatal function and reduced epicuticular wax and may not be due to poor water
transport associated with vascular connection. 相似文献
20.
Restriction site maps and a clone bank of chloroplast DNA (cpDNA) ofMahonia higginsae (Munz)Ahrendt (Berberidaceae) were constructed. The size ofMahonia cpDNA was about 167 kb. Precise mapping using gene probes revealed that cpDNA ofM. higginsae has an inverted repeat (IR) 11.5 kb larger than the tobacco IR. The expansion of the IR into the large single copy region has resulted in the duplication of at least ten genes includingpsbB. The phylogenetic distribution of the expanded IR was examined in twenty-five species ofBerberis andMahonia, twenty species representing the fifteen remaining genera of theBerberidaceae, and four species from four allied families. Our survey indicates that only the species of the closely related generaBerberis andMahonia share the 11.5kb expansion of IR. This result supports their close phylogenetic relationship, which has been suggested previously by chromosomal, morphological, and serological data. 相似文献