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1.
Pyrenochaeta lycopersici is the causal agent of corky root rot, which is a serious disease worldwide that attacks the roots of tomato. A total of 139 isolates were sampled from eight locations in Italy and Israel and assigned to two molecular types (type 1 and type 2) based on internal transcribed spacer (ITS) sequences. These isolates were genotyped using amplified fragment length polymorphisms (AFLPs) to decipher the population structure. Based on this population structure analysis, three groups of P. lycopersici were identified. One group correlated to ITS type 1, while the other two correlated to ITS type 2. amova indicated high genetic divergence (FST = 0·40) between the Italian types 1 and 2. These data support the view that the two ITS types represent significant evolutionary entities, although there might be incomplete lineage sorting present. Some isolates of different ITS type were observed to have very similar multilocus AFLP profiles, and some genotypes were intermediate between the two ITS types. This suggests that parasexual hybridization between the two types has had a significant role in shaping the population structure of P. lycopersici. Finally, the average divergence among the populations within the ITS types was very high (FSC = 0·710, < 10?5), probably due to strong genetic drift and founder effects combined with restricted migration.  相似文献   

2.
Pythium group F is a ubiquitous, though minor, pathogen in several soilless and soil cultures; investigations were carried out to analyze different regions of the DNA and better understand the nature of this group. Fourty-two isolates were obtained from a variety of plants (cucumber, lettuce, tomato) grown in soil or soilless cultures collected in various countries (Canada, Denmark, France, Norway, Sweden and United Kingdom). All Pythium group F isolates displayed amplified ITS1-5,8S-ITS2 ribosomal DNA region (rDNA) of similar length, whereas polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) revealed that, among the seven enzymes used, polymorphism was only identified with Hin6I. After cloning of ITS1-5,8S-ITS2 rDNA region from Pythium group F isolates that displayed restriction polymorphism patterns with Hin6I, comparisons of sequence and restriction mapping data showed a slight variation consisting in a single base change. Inter Simple Sequence Repeat (ISSR)-PCR method was also used to obtain data related to the entire genome and not only to a single DNA region. It identified repeated motifs in the genome of Pythium group F isolates. Two primers (CAC)5 and (CCA)5 detected polymorphism, and isolates were classified among 11 molecular clusters. The genetic diversity of this group was not correlated with the geographical locations or the host plants from which the isolates originated. Polymorphism of Pythium group F isolates pointed out by ISSR is discussed  相似文献   

3.
Stemphylium lycopersici (Enjoji) W. Yamam was initially described from tomato and has been reported to infect different hosts worldwide. Sequence analyses of the internal transcribed spacer (ITS) regions 1 and 2, including 5.8S rDNA (ITS-5.8S rDNA) and glyceraldehyde-3-phosphate dehydrogenase (gpd) gene, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies were conducted to analyze 46?S. lycopersici isolates. Stemphylium lycopersici isolates used in this study were obtained from diseased tomato (Solanum lycopersicum L.), eggplant (Solanum melongena L.), pepper (Capsicum annuum L.) and lettuce (Lactuca sativa L.) from major vegetable growing regions of Malaysia, including the three states of Pahang, Johor and Selangor between 2011 and 2012. Phylogenetic analysis of a combined dataset of the ITS-5.8S rDNA and gpd regions indicated that all isolates were clustered in the sub-cluster that comprised S. lycopersici, and were distinguished from other Stemphylium species. Cluster analyses using the UPGMA method for both RAPD and ISSR markers grouped S. lycopersici isolates into three main clusters with similarity index values of 67 and 68 %. The genetic diversity data confirmed that isolates of S. lycopersici are in concordance to host plants, and not geographical origin of the isolates. All S. lycopersici isolates were pathogenic on their original host plants and showed leaf spot symptoms; however, virulence variability was observed among the isolates. In cross-inoculation assays, the representative isolates were able to cause leaf spot symptoms on eggplant, pepper, lettuce and tomato, but not on cabbage.  相似文献   

4.
To estimate the genetic diversity in 30 isolates ofVerticillium lecanii from aphids, whiteflies, mite and black pine in Japan, including two commercialized strains (Mycotal and Vertalec), DNA polymorphisms in ribosomal DNA of those isolates were analyzed using polymerase chain reaction (PCR). The internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of the nuclear ribosomal RNA gene of each isolate were analyzed by PCR-RFLP (restriction fragment length polymorphism). The size of the PCR product from the ITS region was ~ 580 bp in 27 of the isolates. A 600 bp ITS product was detected in Mycotal and Vertalec. One Japanese isolate produced both the 580 bp and 600 bp products. Enzymatic digestion of the ITS region with Sau3A I,Msp I,Hae III andRsa I revealed RFLPs that consisted of eight haplotypes. Mycotal and Vertalec were specific haplotypes that differed from other isolates. The Japanese isolates had a complex relationship with the original host, but we identified several specific haplotypes common to an aphid origin. Ten distinct IGS haplotypes were detected in the IGS region, some of which were associated with aphid and whitefly origins. These results suggest that the haplotype of rDNA RFLP analysis can be used for studying genetic diversity inV. lecanii.  相似文献   

5.
Twenty-two isolates of Corynespora cassiicola obtained from cucumber, papaya, eggplant, tomato, bean, Vigna, sesame and Hevea rubber (Hevea brasiliensis) were analysed by morphological features, the differences of the ribosomal DNA internal transcribed spacer (rDNA-ITS) region sequence and the inter simple sequence repeat (ISSR) technique. Variability of morphological features was observed among the isolates. Pathogenicity tests showed that isolates from different hosts attacked Hevea rubber. Sequences of two outgroup taxa, C. proliferata and C. citricola, were downloaded from GenBank. The phylogenetic trees were constructed by using the rDNA-ITS region sequences from 24 Corynespora spp. isolates. In this analysis, the 24 sequences grouped into two clusters (A and B). Cluster A consists of sequences from all isolates of C. cassiicola; whereas cluster B consists of the two outgroup taxa, C. proliferata and C. citricola. However, the ITS region is conservative, and is not fit for studying differences among isolates. A total of 114 DNA fragments was amplified with 16 ISSR primers, among which 102 were polymorphic (89.5%). A dendrogram was created by the unweighted pair-group method with arithmetic averaging (UPGMA) analysis, and 22 isolates grouped into three clusters (C, D and E). Cluster C is composed of all of the Hevea rubber isolates, whereas cluster D is composed of nine isolates: four from papaya, five from cucumber, eggplant, bean, vigna and sesame. Cluster E is composed of two isolates from cucumber and tomato. These analyses showed that the genetic diversity was very rich among the tested isolates. There are no correlations between the morphological characteristics or rDNA-ITS region sequences of the 22 isolates and their host or geographical origin, but there is a link between ISSR clusters and their host origins. ISSR markers appear to be useful for intra-species population study in C. cassiicola.  相似文献   

6.
Septoria leaf spot, caused by Septoria lycopersici, is considered one of the most important diseases of tomato in Brazil. Despite its importance, the disease agent is still poorly studied. Septoria isolates collected from different production regions of Brazil were characterized by molecular, morphological, and pathogenic methods. A set of 104 isolates was sequenced for the DNA Tub, Cal, and EF1-α loci. Ten isolates were selected, according to geographical region of origin and type of leaf lesion (typical or atypical), for morphological characterization and for evaluation of aggressiveness on tomato cultivar Santa Clara. To evaluate the pathogen host range, cultivated and wild Solanaceae plants were inoculated with four selected isolates. The results showed that all isolates grouped with the type isolate of S. lycopersici in maximum likelihood and Bayesian inference trees. The isolates were morphologically similar. All isolates selected for pathogenicity testing on tomato were able to induce typical symptoms of the disease, but differed in their aggressiveness. A total of eight species of Solanaceae were also identified as potential alternative hosts for S. lycopersici. This information will provide a more accurate assessment of the risks involved with the introduction of new crops, especially of the genus Solanum, in areas where the species is already present. In addition, it will provide the basis for the establishment of more efficient methods in the management of Septoria leaf spot of tomatoes in natural conditions and in the different production systems.  相似文献   

7.
Five primer/probe sets to identify the tomato wilt pathogen, Fusarium oxysporum f. sp. lycopersici (FOL), and its three races selectively were designed based on the rDNA-intergenic spacer and avirulence genes. Real-time PCR using genomic DNA from mycelia and soil DNA with the primer/probe sets allowed the successful identification of FOL and its races.  相似文献   

8.
In order to characterize the pathogen(s) responsible for the outbreak of fusarium diseases in Algeria, 48 Fusarium spp. isolates were collected from diseased tomato in Algeria and compared with 58 isolates of Fusarium oxysporum originating from seven other Mediterranean countries and 24 reference strains. Partial sequences of the translation elongation factor EF‐1α gene enabled identification of 27 isolates as F. oxysporum, 18 as F. commune and three as F. redolens among the Algerian isolates. Pathogenicity tests confirmed that all isolates were pathogenic on tomato, with disease incidence greater at 28°C than at 24°C. All isolates were characterized using intergenic spacer (IGS) DNA typing, vegetative compatibility group (VCG) and PCR detection of the SIX1 (secreted in xylem 1) gene specific to F. oxysporum f. sp. lycopersici (FOL). No DNA polymorphisms were detected in the isolates of F. redolens or F. commune. In contrast, the 27 Algerian isolates of F. oxysporum were shown to comprise nine IGS types and 13 VCGs, including several potentially new VCGs. As none of the isolates was scored as SIX1+, the 27 isolates could be assigned to F. oxysporum f. sp. radicis‐lycopersici (FORL). Isolates from Tunisia were also highly diverse but genetically distinct from the Algerian isolates. Several Tunisian isolates were identified as FOL by a PCR that detected the presence of SIX1. The results show that isolates from European countries were less diverse than those from Tunisia. Given the difference between Algerian populations and populations in other Mediterranean countries, newly emergent pathogenic forms could have evolved from local non‐pathogenic populations in Algeria.  相似文献   

9.
In four neighbouring regions of southern Italy, Basilicata, Campania, Apulia and Calabria, pepper and zucchini plants showing Phytophthora blight symptoms, tomato plants with either late blight or buckeye rot symptoms, plants of strawberry showing crown rot symptoms and declining clementine trees with root and fruit rot were examined for Phytophthora infections by means of polymerase chain reaction (PCR) assays, using primers directed to nuclear ribosomal DNA (rDNA) repeat sequences. All diseased plants and trees examined tested positive. The detected fungal-like organisms were differentiated and characterized on the basis of primer specificity as well as through extensive restriction fragment length polymorphism (RFLP) and sequence analysis of PCR-amplified rDNA. Phytophthora capsici was identified in diseased pepper and zucchini plants, P. infestans was identified in tomato with late blight symptoms whereas buckeye rot-affected tomatoes and diseased strawberry plants proved to be infected by P. nicotianae and P. cactorum, respectively. Declining clementine trees were infected with P. citrophthora and P. nicotianae in about the same proportion. Also, thirty-one pure culture-maintained isolates of Phytophthora which had previously been identified in southern Italy by traditional methods but were never examined molecularly, were examined by RFLP and sequence analysis of PCR-amplified nuclear rDNA. Among these, an isolate from gerbera which had previously been identified by traditional methods only at genus level, was assigned to P. tentaculata. For the remaining pure culture-maintained isolates examined, the molecular identification data obtained corresponded with those delineated by traditional methods. Most of the diseases examined were already known to occur in southern Italy but the pathogens were molecularly detected and fully characterized at nuclear rDNA repeat level only from other geographic areas, very often outside Italy. A new disease to southern Italy was the Phytophthora blight of zucchini. This is also the first report on the presence and molecular identification of P. tentaculata from Italy.  相似文献   

10.
The isolation of Pyrenochaeta lycopersici, causal agent of corky root of tomato, is difficult because of its slow growth and poor sporulation. Identification is complicated due the existence of two morphologically similar forms, Types 1 and 2, that differ in several physiological and molecular features. For the rapid and unambiguous identification of isolates, two oligonucleotide primer pairs were designed using ITS region sequences. Specific PCR products of 147 and 209 bp were obtained for isolates of Type 1 and Type 2, respectively. Specificity of both primer pairs was verified using several fungal and bacterial species. As little as 0.7 pg of target DNA could be detected with the protocol. A nested PCR procedure was necessary for the detection of the fungus in plant tissue. This technique will be of use in epidemiological studies and in the implementation of control strategies.  相似文献   

11.
ABSTRACT Thirty-nine isolates of Fusarium oxysporum were collected from tomato plants displaying wilt symptoms in a field in California 2 years after F. oxysporum f. sp. lycopersici race 3 was first observed at that location. These and other isolates of F. oxysporum f. sp. lycopersici were characterized by pathogenicity, race, and vegetative compatibility group (VCG). Of the 39 California isolates, 22 were in VCG 0030, 11 in VCG 0031, and six in the newly described VCG 0035. Among the isolates in VCG 0030, 13 were race 3, and nine were race 2. Of the isolates in VCG 0031, seven were race 2, one was race 1, and three were nonpathogenic to tomato. All six isolates in VCG 0035 were race 2. Restriction fragment length polymorphisms (RFLPs) and sequencing of the intergenic spacer (IGS) region of rDNA identified five IGS RFLP haplotypes, which coincided with VCGs, among 60 isolates of F. oxysporum from tomato. Five race 3 isolates from California were of the same genomic DNA RFLP haplotype as a race 2 isolate from the same location, and all 13 race 3 isolates clustered together into a subgroup in the neighbor joining tree. Collective evidence suggests that race 3 in California originated from the local race 2 population.  相似文献   

12.
Stripe rust of wheat caused by Puccinia striiformis f. sp. tritici has recently become a production problem on wheat in Alberta, Canada, and stripe rust of barley caused by Pstriiformis f. sp. hordei occurs regularly. A total of 261 isolates of Pstriiformis were collected from wheat, barley, Hordeum jubatum and triticale plants in Alberta, Canada from 2007 to 2012, and compared to isolates from other provinces and the USA. The genetic diversity of the pathogen was assessed using 11 simple sequence repeat (SSR) markers and by examining a length polymorphism in the ribosomal DNA (rDNA) intergenic spacer 1 (IGS1) region. A total of 28 SSR genotypes were detected within Alberta. The 13 genotypes common on wheat (Pstriiformis f. sp. tritici) were distinct from the 15 genotypes common on barley (Pstriiformis f. sp. hordei). Four SSR genotypes, two within each forma specialis, represented 85% of the isolates recovered. Genotypic diversity was low, population genetic analysis indicated a clonal structure, and the genotypes were widely dispersed. In both formae speciales, the dominant genotype varied between years. The second most common Pstriiformis f. sp. hordei genotype was found to be more closely related to older Pstriiformis f. sp. tritici genotypes from the USA than to other Pstriiformis f. sp. hordei genotypes.  相似文献   

13.
Isolates of Rhizoctonia solani AG2-2 obtained from turf with symptoms of large-patch disease of warm-season turfgrasses were compared with known AG2-2 isolates belonging to cultural types IIIB and IV. Some isolates that were previously identified as type IV have been separated here and named LP isolates. Comparisons among isolates were based on cultural morphology, hyphal growth rate, pathogenicity and restriction fragment length polymorphism (RFLP) analysis in the nuclear encoded ribosomal DNA (rDNA) genes. The cultural characteristics of LP isolates varied from those of types IIIB and IV. LP isolates did not show distinct sclerotial formation and zonation, and the colour of their mycelia and pigment deposition was dark brown. LP isolates had slower hyphal growth rates than types IIIB and IV, with an optimum temperature of 25°C compared with 28°C for types IIIB and IV. LP isolates were less virulent on radish but highly virulent on zoysia grass when compared with isolates of types IIIB and IV. Genomic DNA was digested separately with Eco RI, Ban III, Xba I and Sal I, and probed with cloned rDNA from Alternaria alternata in Southern hybridizations. LP isolates had one RFLP pattern, while both IIIB and IV possessed four different patterns each. Cluster analysis of RFLPs showed that R. solani AG2-2 is divided into three genetic subgroups, consisting of the IIIB, IV and LP isolates, respectively. The polymerase chain reaction (PCR) amplified rDNA internally transcribed spacer (ITS) regions of the IIIB, IV and LP isolates had the same length but produced different restriction patterns when digested with Msp I and Taq I. These results indicate that there are three cultural types in R. solani AG2-2, namely IIIB, IV and LP.  相似文献   

14.
Bacterial speck caused byPseudomonas syringae pv.tomato is an emerging disease of tomato in Tanzania. Following reports of outbreaks of the disease in many locations in Tanzania, 56 isolates ofP. syringae pv.tomato were collected from four tomato- producing areas and characterized using pathogenicity assays on tomato, carbon source utilization by the Biolog Microplate system, polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. All theP. syringae pv.tomato isolates produced bacterial speck symptoms on susceptible tomato (cv. ‘Tanya’) seedlings. Metabolic fingerprinting profiles revealed diversity among the isolates, forming several clusters. Some geographic differentiation was observed in principal component analysis, with isolates from Arusha region being more diverse than those from Iringa and Morogoro regions. The Biolog system was efficient in the identification of the isolates to the species level, as 53 of the 56 (94.6%) isolates ofP. syringae pv.tomato were identified asPseudomonas syringae. However, only 23 isolates out of the 56 (41.1%) were identified asPseudomonas syringae pv.tomato. The results of this work indicate the existence ofP. syringae pv.tomato isolates in Tanzania that differ significantly from those used to create the Biolog database. RFLP analysis showed that the isolates were highly conserved in theirhrpZ gene. The low level of genomic diversity within the pathogen in Tanzania shows that there is a possibility to use resistant tomato varieties as part of an effective integrated bacterial speck management plan. http://www.phytoparasitica.org posting August 8, 2008.  相似文献   

15.
Tomato leaves showing severe leaf spot symptoms have been observed and sampled in the central west and southwest Taiwan during 2015 and 2016. The symptoms were similar to those of bacterial leaf spot/late blight diseases, but only Stemphylium-like fungi were consistently isolated from the diseased tomato. Upon spray inoculation of tomato, Stemphylium-like isolates caused leaf spot symptoms identical to those of naturally infected plants, and the pathogenic isolates were successfully re-isolated from inoculated leaves. The tomato-pathogenic isolates were identified as S. lycopersici based on morphological characterization and molecular identification. S. lycopersici has been previously reported to cause gray leaf spot of tomato in the temperate regions, but the majority of S. lycopersici-caused lesions were black/dark brown rather than gray in our surveillance. Accordingly, it is suggested that S. lycopersici-caused disease of tomato is named Stemphylium leaf spot of tomato more appropriately than tomato gray leaf spot. Moreover, S. lycopersici-caused leaf spot disease on tomato has been distributed in major tomato production regions in Taiwan. The information provided by our study will be important for future breeding of tomato cultivars, especially for tomato producers in Taiwan.  相似文献   

16.
Three evolutionary lineages of the tomato wilt pathogen Fusarium oxysporum f. sp. lycopersici were found among a worldwide sample of isolates based on phylogenetic analysis of the ribosomal DNA intergenic spacer region. Each lineage consisted of isolates mainly belonging to a single or closely related vegetative compatibility group (VCG) and a single mating type (MAT). The first lineage (A1) was composed of isolates VCG 0031 and MAT1-1; the second (A2) included VCG 0030 and/or 0032 and MAT1-1; and the third (A3) included VCG 0033 and MAT1-2. Race 1 and race 2 isolates belonged to the A1 or A2 lineages, and race 3 belonged to A2 or A3 lineages, suggesting that there is no correlation between race and lineage. However, for the isolates from Japan, race 1 (with one exception), race 2, and race 3 isolates belonged to A2, A1, and A3 lineages, respectively. These results suggest that the races could have evolved independently in each lineage; and in Japan the present races were likely to have been introduced independently after they had evolved in other locations.  相似文献   

17.
Restriction fragment length polymorphisms (RFLP) of the intergenic spacer region (IGS) of rDNA and random amplified polymorphic DNA (RAPD) markers were used to survey genetic variability among 181 isolates of Sclerotinia homoeocarpa from Ontario and 10 isolates from Japan. RAPD and IGS-RFLP analyses revealed polymorphisms within and between populations of S . homoeocarpa , distinguishing 151 genotypes. Both types of markers gave similar results in phenetic analysis of genetic distances between populations. Cluster analysis showed that Japanese isolates of S. homoeocarpa were genetically distinct from Ontario isolates, demonstrating significant intraspecific differentiation. An average genetic similarity of 0.66 was found between Japanese isolates. Among Ontario isolates, average genetic similarity was 0.86, and genotypic diversity analysis showed that 49.3% of the total genetic variation observed within Ontario populations occurred among individuals within populations compared to 50.7% between populations. Gametic linkage disequilibrium analysis within Ontario populations revealed an average 15.6% significant nonrandom associations between putative RAPD loci, and that half of the populations showed signs of significant linkage disequilibrium. These results suggest that both clonal propagation and recombination events occurred in local populations of S. homoeocarpa . The high level of genetic similarity between populations and the low levels of intraspecific genetic variation may reflect a small founding population for southern Ontario isolates of S. homoeocarpa .  相似文献   

18.
Twenty-three isolates of Colletotrichum gloeosporioides, five isolates of C. acutatum, two isolates of C. capsici and six isolates of C. boninense associated with anthracnose disease on coffee (Coffea spp.) in Vietnam were identified based on morphology and DNA analysis. Phylogenetic analysis of DNA sequences from the internal transcribed spacer region of nuclear rDNA and a portion of mitochondrial small subunit rRNA were concordant and allowed good separation of the taxa. We found several Colletotrichum isolates of unknown species and their taxonomic position remains unresolved. The majority of Vietnamese isolates belonged to C. gloeosporioides and they grouped together with the coffee berry disease (CBD) fungus, C. kahawae. However, C. kahawae could be distinguished from the Vietnamese C. gloeosporioides isolates based on ammonium tartrate utilization, growth rate and pathogenicity. C. gloeosporioides isolates were more pathogenic on detached green berries than isolates of the other species, i.e. C. acutatum, C capsici and C. boninense. Some of the C. gloeosporioides isolates produced slightly sunken lesions on green berries resembling CBD symptoms but it did not destroy the bean. We did not find any evidence of the presence of C. kahawae in Vietnam.  相似文献   

19.
Tree tomato, Solanum betaceum, is an Andean fruit crop previously shown to be attacked by Phytophthora andina in Ecuador and Colombia. Blight‐like symptoms were discovered on tree tomato plants in the central highlands of Peru in 2003 and shown to be caused by P. andina. Isolates of P. andina, collected from three different plantations in Peru over a 6‐year time span (2003–2008), were compared genetically with P. andina isolates from Colombia and Ecuador to test whether the pathogen population is geographically structured in the Andes. Restriction fragment length polymorphism (RFLP), mitochondrial DNA and simple sequence repeat (SSR) genetic markers, and mating type behaviour indicated that the Peruvian P. andina population from tree tomato is genetically distinct from populations infecting tree tomato in Colombia (CO‐1) and Ecuador (EC‐3, Ia, A1), but is more similar to the population infecting solanaceous hosts of the Anarrhichomenum complex (EC‐2, Ic, A2). Such geographic substructuring within this pathogen species could result from spatial isolation. Most strikingly, in contrast to the Ecuadorian and Colombian P. andina isolates from tree tomato, the Peruvian isolates have the A2 mating type. The presence of both mating types in the Andean population of P. andina attacking tree tomato indicates a risk of sexual reproduction and the presence of long‐lasting oospores in this pathosystem.  相似文献   

20.
The presence of phytoplasmas in seven coniferous plant species (Abies procera, Pinus banksiana, P. mugo, P. nigra, P. sylvestris, P. tabuliformis and Tsuga canadensis) was demonstrated using nested PCR with the primer pairs P1/P7 followed by R16F2n/R16R2. The phytoplasmas were detected in pine trees with witches’ broom symptoms growing in natural forest ecosystems and also in plants propagated from witches’ brooms. Identification of phytoplasmas was done using restriction fragment length polymorphism analysis (RFLP) of the 16S rDNA gene fragment with AluI, MseI and RsaI endonucleases. All samples showed RFLP patterns similar to the theoretical pattern of ‘Candidatus Phytoplasma pini’, based on the sequence of the reference isolate Pin127S. Nested PCR‐amplified products, obtained with primers R16F2n/R16R2, were sequenced. Comparison of the 16S rDNAs obtained revealed high (99·8–100%) nucleotide sequence identity between the phytoplasma isolates. The isolates were also closely related to four other phytoplasma isolates found in pine trees previously. Based on the results of RFLP and sequence analyses, the phytoplasma isolates tested were classified as members of the ‘Candidatus Phytoplasma pini’, group 16SrXXI.  相似文献   

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