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1.
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2.
Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) are well-known legume-infecting potyviruses. The incidences of BCMV and BCMNV infections were determined by ELISA in 367 seed and leaf samples which were collected in 15 common bean-growing provinces of Turkey. Of the samples tested, 67 (18.2 %) occurred to be infected with BCMV, however only 5 (1.4 %) were infected with BCMNV. A total of 45 ELISA-positive samples were selected from single-virus infected ones to determine BCMV and BCMNV pathogenicity groups (PGs) by using a set of bean cultivars that contain different combinations of resistance genes. Some BCMV populations exhibiting unusual pathogenicity were identified. One of them, named TR-180, was found to overcome resistance conferred by bc-1, bc-1 2 , bc-2 and bc-2 2 recessive alleles in common bean and assigned to PG VII. This isolate shared high (99 %) sequence identity with previously identified BCMV RU-1 and RU-1-related strains (RU1-OR-B and RU1-OR-C) according to a BLAST analysis of the nucleotide sequences of RT-PCR amplified products comprising the complete coat protein and 3′ partial NIb regions. The isolates TR-203 and TR-256 produced a distinctive reaction pattern in the dominant I gene-bearing bean cultivars Amanda and Isabella at lower (<30 °C) temperatures and were classified into PG IVb. These isolates were found to be 99 % identical to US-1 strain based on 3′ terminal nucleotide sequences of the BCMV genome. A fourth isolate, TR-243, involved mixed BCMV populations, as confirmed by partial nucleotide sequence analysis; one was classified as belonging to PG VII being similar to TR-180, and another was assigned to PG IVb. In conclusion, on the basis of both the reactions of differential bean cultivars and ELISA results, most of BCMV isolates were assigned to pathogroup PG VII and BCMNV isolates to PG VIb. This study is the first to show that four recessive resistance alleles of common bean can be overcome by a single field isolate of BCMV, and that a wide range of BCMV pathogroups are present in Turkey.  相似文献   

3.
ABSTRACT A quantitative method to screen common bean (Phaseolus vulgaris) plants for resistance to Bean common mosaic necrosis virus (BCMNV) is described. Four parameters were assessed in developing the quantitative method: symptoms associated with systemic virus movement, plant vigor, virus titer, and plant dry weight. Based on these parameters, two rating systems (V and VV rating) were established. Plants from 21 recombinant inbred lines (RILs) from a Sierra (susceptible) x Olathe (partially resistant) cross inoculated with the BCMNV-NL-3 K strain were used to evaluate this quantitative approach. In all, 11 RILs exhibited very susceptible reactions and 10 RILs expressed partially resistant reactions, thus fitting a 1:1 susceptible/partially resistant ratio (chi(2) = 0.048, P = 0.827) and suggesting that the response is mediated by a single gene. Using the classical qualitative approach based only on symptom expression, the RILs were difficult to separate into phenotypic groups because of a continuum of responses. By plotting mean percent reduction in either V (based on visual symptoms) or VV (based on visual symptoms and vigor) rating versus enzyme-linked immunosorbent assay (ELISA) absorbance values, RILs could be separated clearly into different phenotypic groups. The utility of this quantitative approach also was evaluated on plants from 12 cultivars or pure lines inoculated with one of three strains of BCMNV. Using the mean VV rating and ELISA absorbance values, significant differences were established not only in cultivar and pure line comparisons but also in virus strain comparisons. This quantitative system should be particularly useful for the evaluation of the independent action of bc genes, the discovery of new genes associated with partial resistance, and assessing virulence of virus strains.  相似文献   

4.
ABSTRACT A multiplex real-time polymerase chain reaction (PCR) assay was developed to simultaneously genotype plants for the I and bc-1(2) alleles, which condition resistance in beans to Bean common mosaic virus and Bean common mosaic necrosis virus. A segregating F(2) population was derived from the cross between pinto bean breeding line P94207-189A (bc-1 bc-1 I I) and Olathe (bc-12 bc-1(2) i i). Real-time PCR assays were developed that were specific for each allele, and a multiplex PCR reaction could unambiguously assign F(2) plants to one of nine genotypes. Remnant F(1) plants were used as a comparative reference sample. PCR results among this sample fit a normal distribution for both real-time PCR assays, and 99% probability distributions were determined for heterozygotes. F(2) plants were genotyped based on results relative to the probability distributions for heterozygotes. F(2) plants also were genotyped for the I and bc-1(2) alleles by performing F(3) family progeny tests for virus resistance. Agreement between the two methods was 100% (198/198) for the bc-1(2) allele, and 92.4% (183/198) for the I allele. Erroneous genotyping was due to recombination between the amplicon and the I allele. Realtime PCR assays provide a robust method for genotyping seedlings and, in some cases, may eliminate the need for progeny testing.  相似文献   

5.
Bean common mosaic virus (BCMV), belonging to the family Potyviridae, is a serious pathogen of common bean (Phaseolus vulgaris L.) causing considerable economic losses owing to seed, sap and aphid transmissibility. The viral nature of the test isolates and identity of the virus as BCMV were confirmed by mechanical transmission and DAS-ELISA using BCMV antiserum. Pathogenic variability studies in BCMV infecting common bean (Phaseolus vulgaris L.) in Jammu and Kashmir (a northwestern Himalayan state of India), revealed the existence of three pathogroups – PG-I, PG-II and PG-VII, accommodating five strains (NL-1, NL-1n, NL-4, NL-7 and NL-7n). Comparative sequence analysis of coat protein gene revealed that the strains NL-1, NL-4 and NL-7 shared more than 90% amino acid sequence homology with other BCMV isolates from other countries. DAG motif as well as BCMV specific conserved motif MVWCIDN were present in all the three strains. Phylogenetic analysis of coat protein also clustered them in the BCMV group. This study confirmed the occurrence of BCMV and its strains on common bean in Kashmir.  相似文献   

6.
Bean common mosaic necrosis virus (BCMNV) was isolated from Centrosema pubescens, Crotalaria incana, Lablab purpureus, Phaseolus lunatus, Senna bicapsularis, S. sophera, Vigna vexillata and an unidentified Crotalaria species growing in Uganda. Thirteen distinct isolates were characterized using symptoms, pathogenicity in differential bean cultivars, serology, immunosorbent electron microscopy, and seed and aphid transmission. Some isolates conformed with the characteristics of previously described strains of BCMNV but others showed novel properties. All isolates reinfected the natural host from which they were obtained. The origin and ecological significance of these isolates is discussed.  相似文献   

7.
ABSTRACT The complete nucleotide (nt) sequences of the cloned DNA-A (2644 nts) and DNA-B (2609 nts) components of Bean golden yellow mosaic virus (BGYMV-MX) from Chiapas, Mexico were determined. The genome organization of BGYMV-MX is similar to that of other Western Hemisphere bipartite geminiviruses (genus Begomovirus). Infectivity of the cloned BGYMV-MX DNA components in common bean (Phaseolus vulgaris) plants was demonstrated by particle bombardment and agroinoculation. BGYMV-MX was identified as a BGYMV (previously type II BGMV) isolate based on sequence analyses, sap-transmissibility, and pseudorecombination experiments with other bean-infecting begomoviruses. On the basis of differences in the DNA-B hypervariable region, symptom phenotype, and properties of infectious pseudorecombinants, BGYMV-MX may represent a distinct strain of BGYMV. Pseudorecombination experiments further established that BGYMV symptom determinants mapped to DNA-B, and that BGYMV-MX was most closely related to BGYMV from Guatemala. A Tomato leaf crumple virus (TLCrV) DNA-A/BGYMV-MX DNA-B pseudorecombinant was infectious in bean, establishing that a viable reassortant can be formed between begomovirus species from different phylogenetic clusters. Bean germ plasm representing the two major gene pools (Andean and Mesoamerican) was screened for response to BGYMV-MX with three methods of inoculation: sap-inoculation, particle bombardment, and agroinoculation. Andean germ plasm was very susceptible and similar results were obtained with all three methods, whereas Mesoamerican germ plasm showed resistance to BGYMV-MX, particularly with agroinoculation.  相似文献   

8.
Common bacterial blight (CBB) in edible beans (Phaseolus vulgaris), incited Xanthomonas campestris pv. phaseoli, reduces bean yields and seed quality. The main objective of this study was to determine resistance to common bacterial blight in bean genotypes. Twenty-two bean genotypes grown in Turkey including common and snap bean cultivars/lines were collected from different parts of Turkey and tested for resistance against to Xanthomonas campestris pv. phaseoli strain MFD-11. All the common and snap bean lines/cultivars tested were moderately susceptible, susceptible or highly susceptible, except AG-7117 which was found resistant to Xanthomonas campestris pv. phaseoli. This is the first report of a resistance source in a common bean line (AG-7117) against Xanthomonas campestris pv. phaseoli.  相似文献   

9.
Journal of Plant Diseases and Protection - Bean common mosaic virus (BCMV) is a major seed transmitted virus of common bean (Phaseolus vulgaris). The use of virus-free germplasm is a prerequisite...  相似文献   

10.
ABSTRACT Common bacterial blight (CBB) disease of the common bean (Phaseolus vulgaris) is caused by Xanthomonas campestris pv. phaseoli and the brown-pigmented variant X. campestris pv. phaseoli var. fuscans. CBB first was described in Castilla y León County, Spain, in 1940, and is now a major constraint on common bean production. In this secondary center of diversity of the common bean, large-seeded Andean cultivars predominate, although medium-seeded Middle American cultivars also are grown. Xanthomonad-like bacteria associated with CBB in Castilla y León were characterized on the basis of carbohydrate metabolism, brown pigment production, genetic analyses (repetitive-element polymerase chain reaction [rep-PCR] and random amplified polymorphic DNA [RAPD]) and pathogenicity on cultivars representing the two common bean gene pools (Andean and Middle American). X. campestris pv. phaseoli was more prevalent (80%) than X. campestris pv. phaseoli var. fuscans (20%). Patterns of carbohydrate metabolism of Spanish CBB bacteria were similar to those of known strains; and only X. campestris pv. phaseoli var. fuscans strains utilized mannitol as a sole carbon source. rep-PCR and RAPD analyses revealed relatively little genetic diversity among Spanish X. campestris pv. phaseoli strains, and these strains were placed together with New World strains into a large cluster. Similar to other New World strains, representative Spanish X. campestris pv. phaseoli strains were highly pathogenic on bean cultivars of both gene pools, showing no gene pool specialization such as that found in certain East African strains. Genetic analyses and pathogenicity tests confirmed and extended previous results, indicating that these East African strains represent distinct xanthomonads that independently evolved to be pathogenic on common bean. X. campestris pv. phaseoli var. fuscans strains were more closely related and genetically distinct from X. campestris pv. phaseoli strains. However, two distinct clusters of X. campestris pv. phaseoli var. fuscans strains were identified, one having the most New World strains and the other having the most African strains. Spanish strains were placed in both clusters, but all strains tested were highly pathogenic on bean cultivars of both gene pools. Together, our results are consistent with multiple introductions of CBB bacteria into Spain. These findings are discussed in terms of breeding for CBB resistance and the overall understanding of the genetic diversity and evolution of CBB bacteria.  相似文献   

11.
ABSTRACT Macroptilium lathyroides, a perennial weed in the Caribbean region and Central America, is a host of Macroptilium yellow mosaic Florida virus (MaYMFV) and Macroptilium mosaic Puerto Rico virus (MaMPRV). The genomes of MaYMFV and MaMPRV were cloned from M. lathyroides and/or field-infected bean and the DNA sequences were determined. Cloned A and B components for both viruses were infectious when inoculated to M. lathyroides and common bean. Comparison of the DNA sequences for cloned A and B components with well-studied begomovirus indicated that MaMPRV (bean and M. lathyroides) and MaYMFV (M. lathyroides) are unique, previously undescribed begomo-viruses from the Western Hemisphere. Phylogenetic analysis of viral A components indicated that the closest relative of MaYMFV are members of the Bean golden yellow mosaic virus (BGYMV) group, at 76 to 78% nucleotide identity, whereas the closest relative for the A component of MaMPRV was Rhynchosia golden mosaic virus at 78% nucleotide identity. In contrast, BGYMV is the closest relative for the B component of both MaYMFV and MaMPRV, with which they share approximately 68.0 and approximately 72% identity, respectively. The incongruent taxonomic placement for the bipartite components for MaMPRV indicates that they did not evolve entirely along a common path. MaYMFV and MaMPRV caused distinctive symptoms in bean and M. lathyroides and were transmissible by the whitefly vector and by grafting; however, only MaYMFV was mechanically transmissible. The experimental host range for the two viruses was similar and included species within the families Fabaceae and Malvaceae, but only MaYMFV infected Malva parviflora and soybean. These results collectively indicate that MaMPRV and MaYMFV are new, previously undescribed species of the BGYMV group, a clade previously known to contain only strains and isolates of BGYMV from the Caribbean region that infect Phaseolus spp. Both MaYMFV and MaMPRV may pose an economic threat to bean production in the region.  相似文献   

12.
The susceptibility/resistance to Aphanomyces euteiches of various genotypes (cultivars and breeding lines) of several grain legume species was assessed in controlled conditions. A total of 279 genotypes from the major grain legumes grown in temperate climates (faba bean, chickpea, lentil, lupin and common vetch) and three other legumes frequently cultivated in France (French bean, clover and alfalfa) were screened with one pea-infecting isolate from France. Four different categories of susceptibility/resistance were identified among the legume species/cultivars tested with the pea A. euteiches isolate: (1) susceptible legume species (lentil, alfalfa, French bean) among which low levels of partial resistance was observed; (2) legume species including susceptible genotypes and genotypes with high levels of resistance (common vetch, faba bean and clover), (3) species with a very high level of resistance (chickpea) and (4) species displaying no symptoms (lupin). It is therefore important to consider pathogen-species and pathogen-genotype interactions when defining the host specificity of A. euteiches and considering the possible role of different legume species in increasing or decreasing the soil inoculum potential.  相似文献   

13.
ABSTRACT A random amplified polymorphic DNA (RAPD) marker directly linked (0.0 cM) with a resistance gene was identified in a snap bean recombinant inbred population (Moncayo x Primo) consisting of 94 F(5:7) recombinant inbred lines that had uniform segregation for disease reaction to Beet curly top virus (BCTV) across three field locations. Resistance was conditioned by a single dominant allele tentatively designated Bct. Seven hundred and fifty decamer primers were screened to obtain the linked RAPD marker that was then converted to a sequence characterized amplified region (SCAR) marker SAS8.1550. The SCAR mapped within a cluster of resistance genes on linkage group B7 of the core map. A survey of 103 BCTV-resistant and -susceptible snap and dry bean genotypes was conducted using SAS8.1550. Results showed that the SCAR would be highly useful for marker-assisted selection of Bct in snap and dry bean originating from the Andean gene pool. Marker-assisted selection for Bct will expedite the development of BCTV-resistant cultivars and minimize the need for cumbersome pathogen tests.  相似文献   

14.
ABSTRACT New cultivars of the common bean (Phaseolus vulgaris) with durable resistance to anthracnose can be developed by pyramiding major resistance genes using marker-assisted selection. To this end, it is necessary to identify sources of resistance and molecular markers tightly linked to the resistance genes. The objectives of this work were to study the inheritance of resistance to anthracnose in the cultivar TO (carrying the Co-4 gene), to identify random amplified polymorphic DNA (RAPD) markers linked to Co-4, and to introgress this gene in the cultivar Rudá. Populations F(1), F(2), F(2:3), BC(1)s, and BC(1)r from the cross Rudá x TO were inoculated with race 65 of Colletotrichum lindemuthianum, causal agent of bean anthracnose. The phenotypic ratios (resistant/susceptible) were 3:1 in the F(2) population, 1:1 in the BC(1)s, and 1:0 in the BC(1)r, confirming that resistance to anthracnose in the cultivar TO was monogenic and dominant. Six RAPD markers linked to the Co-4 gene were identified, four in the coupling phase: OPY20(830C) (0.0 centimorgan [cM]), OPC08(900C) (9.7 cM), OPI16(850C) (14.3 cM), and OPJ01(1,380C) (18.1 cM); and two in the repulsion phase: OPB03(1,800T) (3.7 cM) and OPA18(830T) (17.4 cM). OPY20(830C) and OPB03(1,800T), used in association as a codominant pair, allowed the identification of the three genotypic classes with a high degree of confidence. Marker OPY20(830C), which is tightly linked to Co-4, is being used to assist in breeding for resistance to anthracnose.  相似文献   

15.
Z. Mersha  B. Hau 《Plant pathology》2008,57(4):674-686
Epidemics of bean rust ( Uromyces appendiculatus ) and their effects on host dynamics of common bean ( Phaseolus vulgaris ) were studied in three controlled greenhouse experiments, with and without fungicide sprays, on two susceptible bean cultivars, Dufrix and Duplika. Bean plants were artificially inoculated with a suspension of 105 U. appendiculatus urediniospores mL−1 water and temporal disease progress, as well as host growth dynamics (leaf size and defoliation), were monitored on a leaflet basis in comparison with non-inoculated plants, which were sprayed with deionized water. Progress curves of bean rust, expressed as the proportion of leaf area occupied by pustules (uredinia), or as the proportion occupied by total lesion area (= halo areas + pustule area), were well described by logistic functions with maximum disease levels clearly lower than 1. Bean rust epidemics substantially affected host growth by reducing the total leaf area formed by 17·4–35·6% and 35·3–46·2% compared with healthy plants for cvs Dufrix and Duplika, respectively. Fungicide sprays mitigated the negative effect of bean rust, leading to a gain in leaf area of 17–21% compared with unsprayed plants in both cultivars in two experiments, while in another experiment, disease control had no effect in Dufrix, but a clear effect in Duplika. In addition to the growth depression, bean rust also led to pronounced losses of leaf area as a result of reduced leaf size (leaf shrivelling) and accelerated defoliation.  相似文献   

16.
About 90 barley cultivars mostly of European or Japanese origin, were grown for 2–5 years at eight sites in China where barley yellow mosaic virus was known to occur. The sites were selected because they had previously been used to screen breeding lines and some differences between them in cultivar response had been suspected. ELISA tests showed that symptomless plants were not infected by the virus and the proportions of plants with symptoms were therefore recorded as a measure of susceptibility. European cultivars carrying the ym4 gene, which confers resistance to the common European strain, were usually resistant at two sites but susceptible at the others, but one (cv. Energy) was resistant at all sites. Eleven of the Japanese cultivars showed differential responses between sites but there was no correspondence with strains recognized in Japan. There are probably several distinct Chinese strains but further experiments would be needed to identify them. The Japanese cultivars Chosen, Hagane Mugi, Iwate Mensury 2 and Mokusekko 3 seem to be resistant to all known virus strains and are probably the most useful for plant breeders.  相似文献   

17.
ABSTRACT Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Málaga virus are monopartite begomoviruses (genus Begomovirus, family Geminiviridae) that infect common bean (Phaseolus vulgaris), causing bean leaf crumple disease (BLCD). This disease was found to be widespread in southern Spain and causes stunted growth, flower abortion, and leaf and pod deformation in common bean plants. Commercial yield losses of up to 100% occur. In the present study, we have identified and characterized a resistance trait to BLCD-associated viruses in the common bean breeding line GG12. This resistance resulted in a complete absence of BLCD symptoms under field conditions or after experimental inoculation. Our analysis showed that virus replication was not inhibited. However, a severe restriction to systemic virus accumulation occurred in resistant plants, suggesting that cell-to-cell or long-distance movement were impaired. In addition, recovery from virus infection was observed in resistant plants. The reaction of P. vulgaris lines GG12 (resistant) and GG14 (susceptible), and of F(1), F(2), and backcross populations derived from them, to TYLCV inoculation suggested that a single dominant gene conferred the BLCD resistance described here.  相似文献   

18.
Severe mosaic with leaf malformation and green vein banding was observed on yam bean in West and Central Java, Indonesia. Virions of the causal virus were flexuous filaments, about 700 nm in length, with a coat protein of 30 kDa. The virus was transmitted by mechanical inoculation and by aphids in a nonpersistent manner. The nucleotide sequence of the coat protein gene had the highest identity with that of Bean common mosaic virus (BCMV, genus Potyvirus) isolate VN/BB2-5. Based on demarcation criteria, including the genome sequence and host range, we tentatively designate this isolate as BCMV-IYbn (Indonesian yam bean). The nucleotide sequence reported is available in the DDBJ/EMBL/GenBank databases under accession number AB289438.  相似文献   

19.
Bean common mosaic virus (BCMV) isolates were collected from crops of Phaseolus vulgaris (bean) and from wild legume species in 13 African countries. Isolates of pathotype VIa from both beans and wild legume species were predominant in central, eastern and southern Africa. Isolates of pathotypes I, III, IVa, IVb and Va were also found. Some isolates did not conform to previously published pathotypes, and therefore represent records of novel pathotypes. The susceptibility of various wild legume species to BCMV was investigated and isolates of the virus obtained from Crotalaria incana, Rhynchosia sp., Macroptilium atropurpureum and Cassia occidentalis (synonym Senna occidentalis) were aphid-transmitted both from P. vulgaris to their original host species and to P. vulgaris. Isolates of BCMV from wild legume species were seed-transmitted in bean and in several other legume species. The natural occurrence of BCMV in wild legume species in Africa is probably a significant factor in the ecology and epidemiology of the virus and possibly the evolution of isolates of the 'A' serotype which induce necrotic reactions in cultivars carrying the I gene for resistance. The occurrence of viruses other than BCMV from P. vulgaris and other legume hosts is also reported. The gene-for-gene model described by Drijfhout (1978) is reinterpreted to explain the variation for pathogenicity, and it is proposed that there may be genes which control the temperature sensitivity of necrosis in combination with the I gene.  相似文献   

20.
ABSTRACT A polymerase chain reaction approach using degenerate primers that targeted the conserved domains of cloned plant disease resistance genes (R genes) was used to isolate a set of 15 resistance gene analogs (RGAs) from common bean (Phaseolus vulgaris). Eight different classes of RGAs were obtained from nucleotide binding site (NBS)-based primers and seven from not previously described Toll/Interleukin-1 receptor-like (TIR)-based primers. Putative amino acid sequences of RGAs were significantly similar to R genes and contained additional conserved motifs. The NBS-type RGAs were classified in two subgroups according to the expected final residue in the kinase-2 motif. Eleven RGAs were mapped at 19 loci on eight linkage groups of the common bean genetic map constructed at Centro Internacional de Agricultura Tropical. Genetic linkage was shown for eight RGAs with partial resistance to anthracnose, angular leaf spot (ALS) and Bean golden yellow mosaic virus (BGYMV). RGA1 and RGA2 were associated with resistance loci to anthracnose and BGYMV and were part of two clusters of R genes previously described. A new major cluster was detected by RGA7 and explained up to 63.9% of resistance to ALS and has a putative contribution to anthracnose resistance. These results show the usefulness of RGAs as candidate genes to detect and eventually isolate numerous R genes in common bean.  相似文献   

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