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1.
A nonpathogenic strain of Agrobacterium vitis VAR03-1 was tested as a biological control agent against crown gall of grapevine (Vitis vinifera L.). A mixture of the nonpathogenic strain VAR03-1 and a tumorigenic strain G-Ag-27 of A. vitis at cell ratios of 1 : 1, 3 : 1, 9 : 1, and 99 : 1 significantly inhibited gall formation and size on stems of tomato (Lycopersicon esculentum Mill.). Strain VAR03-1 also inhibited gall formation on stems of both tomato and grapevine at a 1 : 1 cell ratio with several
tumorigenic A. vitis strains isolated from different fields of grapevine in Japan. In biological control tests, when roots of grapevine and tomato
seedlings were soaked in a cell suspension of strain VAR03-1 for 24 h before a 1-h soaking in a cell suspension of the pathogen
and subsequent planting in pots of infested soil, strain VAR03-1 significantly reduced the incidence of gall formation on
both plants. 相似文献
2.
A nonpathogenic strain of Rhizobium vitis, VAR03-1, was tested as a biological control agent for crown gall of apple. When apple tree roots were soaked in a cell suspension of antagonists before planting in the field, treatment with VAR03-1 significantly reduced the number of plants with tumors and the disease severity. The inhibitory effects of treatment with VAR03-1 and the nonpathogenic R. rhizogenes strain K84, which is commercially used as a biological control agent throughout the world, on apple crown gall were almost identical. VAR03-1 was bacteriocinogenic, producing a halo of inhibition against two species of tumorigenic Rhizobium isolated from galled apple trees. Moreover, VAR03-1 established populations on roots of apple tree rootstock and persisted on roots for 437?days. This is the first report that the nonpathogenic R. vitis VAR03-1 effectively controls crown gall of apple. 相似文献
3.
Graft unions of nursery stock of grapevine (Vitis vinifera L.) collected in Japan yielded pathogenic and nonpathogenic strains of Agrobacterium. On the basis of classical diagnostic tests, a sequence analysis, and a multiplex polymerase chain reaction method previously
reported, the pathogenic strain was identified as Agrobacterium tumefaciens biovar 3, whereas the nonpathogenic strains were assigned to Agrobacterium radiobacter biovar 3. Stems of tomato (Lycopersicon esculentum Mill.) seedlings were inoculated with both A. tumefaciens biovar 3 strain G-Ag-27 as a pathogen and one of the control strains isolated from grapevine or A. radiobacter biovar 2 strain K84 as competitors to assay the suppression of gall formation caused by the pathogen. In a test with a 1 : 1
pathogen/nonpathogen cell ratio, all A. radiobacter biovar 3 strains reduced gall incidence and size compared to that of the positive control inoculated only with the pathogen.
Strain VAR03-1 was especially effective in reducing the incidence of gall formation on grapevine and reduced gall size by
84%–100% of those on the positive control. Many tested nonpathogenic biovar 3 strains were bacteriocinogenic, causing an inhibition
zone against A. tumefaciens biovar 3 strains on YMA medium. Strain VAR03-1 was the most effective against indicator strains and appears to be a promising
agent for controlling crown gall of grapevine. 相似文献
4.
A. Palacio-Bielsa R. González-Abolafio B. Álvarez B. Lastra M. A. Cambra C. I. Salcedo M. M. López R. Penyalver 《Plant pathology》2009,58(3):584-593
Fifty-six tumorigenic Spanish grapevine strains of Agrobacterium spp. were tested for biovar classification, pathogenicity on several hosts, opine utilization, 16S rRNA gene sequencing and PCR amplifications using five primer sets targeting chromosomal and Ti plasmid genes. Fifty of them belonged to A. vitis (biovar 3), three to A. tumefaciens (biovar 1) and three to A. rhizogenes (biovar 2). All strains were tumorigenic on grapevines. Most A. vitis strains were also pathogenic on tomato and tobacco plants, while the three A. tumefaciens strains were only pathogenic on grapevine. Although most A. vitis strains used octopine, 12 utilized neither octopine nor nopaline. 16S rRNA gene sequencing clearly distinguished between strains belonging to the three species. Those of A. vitis could be further divided into three chromosomal backgrounds according to their 16S ribosomal RNA gene sequences. No universal primer pair was found for the detection of all three Agrobacterium species isolated from grapevine. DNA from all A. vitis strains was amplified with the chromosomally-encoded pehA primer pair. In both A. vitis and A. tumefaciens a correlation was observed between the amplifications obtained using the tmr and the virA Ti-plasmid-targeting primer pairs. Three types of Ti plasmid were found in A. vitis strains according to their PCR amplifications and opine utilization profiles. A given chromosomal background harboured only one type of Ti plasmid within the strains from each analysed sample, showing a strong association between chromosomal backgrounds and Ti plasmids in A. vitis . 相似文献
5.
放射土壤杆菌MI15菌株生物防治葡萄根癌病的研究 总被引：6，自引：0，他引：6
从内蒙古玫瑰香葡萄冠瘿中分离到一株无致病力的土壤杆菌MI15菌株,经鉴定为放射土壤杆菌(Agrobacterium radiobacter),属生物Ⅰ型。在平皿培养产生的土壤杆菌素,能抑制葡萄根癌土壤杆菌生物Ⅲ型菌株的生长,在温室向日葵幼苗和葡萄嫩枝上接种,MI15菌株能显著地抑制多株不同类型葡萄根癌土壤杆菌诱导形成冠瘿瘤。在琼脂糖凝胶电泳图谱上,MI15菌株有一条质粒带,与生物Ⅰ型根癌士壤杆菌C58菌株的质粒情况基本相同。研究还表明该菌株能在葡萄上存活定殖。 相似文献
6.
7.
Kirara Saito Megumi Watanabe Hidenori Matsui Mikihiro Yamamoto Yuki Ichinose Kazuhiro Toyoda Akira Kawaguchi Yoshiteru Noutoshi 《Journal of General Plant Pathology》2018,84(1):58-64
Rhizobium vitis: strain VAR03-1 is a biological control agent that suppresses grapevine crown gall disease caused by a tumorigenic strain of R. vitis (Ti). Both acetosyringone-induced expression of a virulence gene and the growth of Ti were suppressed in vitro when it was cultivated in the VAR03-1 culture filtrate. These inhibitory effects were reduced by high-temperature treatment or incubation for 72 h. Both activities were detected in the high molecular weight fraction (>?100 kDa) of the filtrate. Our results suggest that the antagonistic effects of VAR03-1 on Ti are mediated by large particle(s) released in the culture media. 相似文献
8.
Crown gall in grapevine, caused by tumorigenic Agrobacterium vitis strains, can cause severe losses in most viticulture regions worldwide. The only effective means of control is through cultivation practices. One non-tumorigenic A. vitis strain, E26, can prevent crown gall infection when applied to wounds on grapevine prior to or simultaneous with inoculation of tumorigenic strains. ME19, a Tn5 mutant of strain E26, was impaired in terms of its ability to be chemo-attracted by grapevine root tissue extracts and its attachment to grapevine roots, and had reduced biological control activity; it did not significantly differ from the wild-type strain of E26 in phenotypes of agrocin production, growth in minimum medium or swarming activity. Complementation of ME19 with the cosmid clone of CP1543 from an E26 DNA library restored the chemotaxis, attachment, and biocontrol phenotypes. A 7·3-kb Kpn I fragment from CP1543 was cloned and sequenced, and sequence analysis revealed that the Tn 5 insertion occurred in a region that shares a significant homology with genes coding for methyl-accepting chemotaxis proteins (MCPs) in many bacteria. Complementation of the mcp gene mutants restored the affected phenotypes to the level of wild-type E26. An in-frame deletion mutant of the mcp gene was generated and was determined to have the same phenotypes as the original Tn5 mutant. 相似文献
9.
ABSTRACT The crown gall pathosystem was used to evaluate a model that describes the dose-response relationship between biological control agents and plant pathogens. The model predicts that this relationship can become asymptotic, such that increased antagonist doses cannot compensate for deficiencies in disease suppression. Wounded roots of tomato (Lycopersicon esculentum) and cherry (Prunus mahaleb) plants were dipped into different concentrations of the biological control organism Agrobacterium radiobacter strain K84 prior to inoculation with the pathogen A. tumefaciens. Pathogen strains sensitive or resistant to the antibiotic agrocin 84 were used, and for tomato experiments, a derivative of A. radiobacter strain K84 that does not produce agrocin 84 also was included as an experimental treatment. As predicted by the dose-response model, the amount of disease suppression per unit of antagonist decreased with increasing antagonist dose and became asymptotic at high antagonist densities. Control of crown gall of tomato was nearly complete with the combination of A. radiobacter K84 and an agrocin 84-sensitive strain of A. tumefaciens. Pathogen resistance to agrocin 84 or lack of agrocin 84 production by A. radiobacter resulted in antagonist dose-crown gall incidence relationships that were apparently asymptotic at levels of control significantly less than 100%. For field-grown cherry, similar dose-response relationships were observed with higher asymptotic levels of disease suppression obtained when trees were inoculated with an agrocin 84-sensitive A. tumefaciens strain compared with an agrocin 84-resistant pathogen strain. The differences among bacterial strain combinations in the magnitude of the asymptote defined by the dose-response relationships suggest that A. radiobacter impacts a smaller proportion of the pathogen population when the activity of agrocin 84 is muted. 相似文献
10.
11.
ABSTRACT Agrobacterium vitis is the causal agent of crown gall disease in grapevine, which can be severe in many regions worldwide. Vitis vinifera cultivars are highly susceptible to freeze injury, providing the wounds necessary for infection by A. vitis. Wound position in relation to the uppermost bud of cuttings was determined to be important in tumor development. Inoculated wounds below buds developed tumors, whereas wounds opposite the bud did not, implying that indole-3-aectic acid flow contributes to tumor formation. If auxin was applied to wounds prior to inoculation with a tumorigenic A. vitis strain, all sites of inoculation developed tumors, accompanied by an increased amount of callus in the cambium. Wounds inoculated with an A. vitis biological control strain F2/5 prior to application of the pathogen did not develop galls. A closer examination of these wounds determined that callus cells formed in the cambium during wound healing are susceptible to transformation by the pathogen. Although the mechanism by which F2/5 prevents transformation is unknown, our observations suggest that F2/5 inhibits normal wound healing by inducing necrosis in the cambium. 相似文献
12.
用K84对我国不同寄主来源的68个Agrobacterium tumefaciens菌株进行生物防治试验,结果表明:K84对我国桃树菌株的防治效果显著,对新疆的啤酒花菌株也有效;但对浙江萧山的部分啤酒花菌株无效;对甜菜菌株的防治效果不佳;对葡萄菌株基本上无效。对致病菌株的质粒类型的研究结果表明:桃树、啤酒花和甜菜菌株基本上都是胭脂碱(Nopaline)型质粒、葡萄菌株基本上是章鱼碱(Octopine)型质拉。试验中还发现不少胭脂碱型菌株不能被K84所防治。此外,在甜菜和毛白杨菌株中也发现了对细菌素A84(agrocin84)敏感,但不能被K84防治的菌株。 相似文献
13.
由致病性根癌土壤杆菌Agrobacteriumspp.侵染引起的根癌病对樱桃等果树生产造成严重的影响。利用双层平板、胡萝卜圆盘法和接种指示植物番茄等方法验证了澳洲生防菌株K1026对2种不同原生物型樱桃冠瘿病病原菌的抑制作用;检测了不同接种时间对病原菌侵染产生瘤状组织的影响,结果显示提前或者在病原菌接种后20h内接种K1026可抑制胡萝卜产生瘤状组织;研究了K1026对大樱桃根癌病的作用机制是产生土壤杆菌素和竞争附着位点;田间试验表明K1026蘸根处理,对‘中国樱桃’株系冠瘿病的防治效果达81.61%,使发病率降低至18.13%。 相似文献
14.
Evidence of Migration and Endophytic Presence of Agrobacterium tumefaciens in Rose Plants 总被引：2，自引：0，他引：2
Rubén Martí Jaime Cubero Antonio Daza Jaime Piquer Carmen I. Salcedo Clara Morente María M. López 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(1):39-50
Agrobacterium tumefaciens was isolated from stem tumors of several rose cultivars showing that the bacterium is the causal agent of aerial galls in rose plants. No differences were observed in the characteristics of the Agrobacterium isolates from crown or aerial galls. Stem inoculation of ten rose cultivars showed that all of them were susceptible to A. tumefaciens but differences in the size of the resulting tumors were observed. The movement of A. tumefaciens in rose plants was demonstrated using two wild type strains and two antibiotic resistant mutants. Three months after inoculation, the inoculated strains were recovered in the roots, crown and below and above the inoculation site but low numbers of pathogenic Agrobacterium cells were isolated. New tumors appeared in 5% of the noninoculated wounds. A. tumefaciens was isolated from the stem at different distances from the tumor in naturally infected plants. In symptomless commercial plants, the isolation from the roots, crown and at different stem levels demonstrated the existence of systemic and latent infections in rose. Direct isolation using a nonselective and selective media with or without a previous enrichment step were efficient methods for isolating tumorigenic Agrobacterium from the different parts of rose plants. 相似文献
15.
根癌病生防菌——葡萄土壤杆菌E26菌株在葡萄植株的定殖研究 总被引：2，自引：0，他引：2
利用绿色荧光蛋白基因(gfp)标记示踪,研究了葡萄根癌病生防菌葡萄土壤杆菌E26菌株应用到田间后在玫瑰香葡萄(Vitis vinifera cv. Muscat Humbug)根表面和根际土壤中的群体数量变化,比较了E26菌株与葡萄根癌病原菌K308菌株室内人工接种后在玫瑰香葡萄苗茎和根外植体伤口部位的附着情况.在田间自然状况下,E26菌株可以在葡萄根表面和根际土壤中存活定殖.接种5个月后,E26在根表面的平均数量为104cfu/g根(鲜重),在根际土壤中的平均数量为104cfu/g土壤(干重).在室内,E26菌株和K308菌株分别单独接种时均能以相似水平附着在葡萄茎和根的伤口;E26和K308以相同数量同时接种时,附着在葡萄伤口细胞的K308的数量显著低于K308单独接种时所附着在葡萄伤口细胞的数量.扫描电镜显微观察证实E26菌株能够和病菌K308菌株一样附着于葡萄根部伤口处. 相似文献
16.
P. G. PSALLIDAS 《EPPO Bulletin》1988,18(1):61-66
Crown gall disease of cultivated plants, caused by Agrobacterium tumefaciens, constitutes a serious problem for the fruit tree, rose and grapevine nurseries in Greece. All three biotypes of A. tumefaciens exist in Greece. Biotypes 1 and 2 have a wide host range being responsible for the disease on fruit trees and roses while biotype 3 isolates have a narrow host range infecting grapevine only. All Greek isolates of biotype 1 and all but 3 isolates of biotype 2 were sensitive to biological control with the antagonistic bacterium A. radiobacter strain K84, but the biotype 3 isolates were insensitive to biocontrol. Experiments on the effectiveness of the method in artificial infections of seedlings as well as in naturally infested soils showed that the method is effective and can be applied without any risk of development of forms insensitive to biocontrol. The use of a lyophilized preparation of K84 with skim milk as suspending medium is recommended. The lyophilized antagonistic bacterium retains its activity and the final concentration (106 cfu ml-) is adequate to protect treated plants from crown gall. 相似文献
17.
ABSTRACT Agrocin-minus mutants of nontumorigenic Agrobacterium vitis strain F2/5 controlled grape crown gall as well as the wild-type strain, indicating that agrocin is not a major factor in the mechanism of biological control. Relative levels of attachment to grape cells by tumorigenic and biocontrol strains were also measured. Attachment of tumorigenic strains (CG49 and K306) and biological control strains (F2/5 and agrocin-minus mutant 1077) was often reduced when mixtures of the strains were applied. However, high populations (10(3) to 10(5) CFU/ml) of all strains attached following mixed inoculations, suggesting that competition for attachment sites is also not a factor in the mechanism of biological control. Transfer of T-DNA to grape by CG49 was prevented or greatly inhibited in the presence of F2/5 or 1077 as measured by expression of the GUS reporter gene. The Ti plasmid virulence genes, however, were induced by exudates from grape shoots that had been inoculated with F2/5. Sonicated and autoclaved preparations of F2/5 and 1077 did not control crown gall or inhibit T-DNA transfer. Control by F2/5 is specific to grape, since gall formation on tomato, sunflower, and Kalanchoe daigremontiana were not inhibited. 相似文献
18.
Twenty-eight strains of Agrobacterium vitis , including both tumorigenic and nonpathogenic phenotypes involving 26 isolated in Japan and strains NCPPB 3554T and NCPPB 2562 isolated in Australia and Greece, respectively, were characterized by means of a slide agglutination test (SAT) using antisera prepared against somatic antigens. Phylogenetic analyses were also carried out, using the results of repetitive sequence-based polymerase chain reaction and the partial nucleotide sequences of pyrG , recA and rpoD . The A. vitis strains separated into four serogroups (A to D) based on the SAT reactivity. The phylogenetic analyses showed A. vitis strains separated into four tumorigenic groups (A to D) and one nonpathogenic group (E). Serogroups A to C corresponded exactly to genetic groups A to C, respectively, whereas serogroup D further divided into two distinct genetic groups, D and E. Genetic group E was isolated in Okayama Prefecture, Japan, and all strains of it have been found to coexist with tumorigenic strains belonging to the other groups within the same galled grapevine tissues. These results suggest that A. vitis strains are genetically heterogeneous and can be separated into several genetic groups. The differences between the nucleotide sequences of pyrG , recA and rpoD of the genetic groups will enable the development of a simple and convenient monitoring method, which will increase understanding of the dynamics of each genetic group of A. vitis in the natural environment. 相似文献
19.
Nine Italian peach nurseries, which use Agrobacterium rhizogenes strain K84 to protect plants from crown gall, were monitored for three years with the aim of determining whether transconjugant populations may arise following plasmid exchanges between K84 and autochtonous soil agrobacteria. Six hundred and seventy-eight Agrobacterium isolates were obtained from 120 tumours developed on apricot and peach rootstocks that had been treated in pre-planting with the antagonist. Agrobacteria were characterized for pathogenicity, biovar, opine catabolism and agrocin 84 sensitivity. Colony hybridization was used for screening the isolates harbouring plasmids pTi and/or pAgK84. Analysis of plasmid content and Southern blotting were performed on putative transconjugant agrobacteria found in tumours collected from one nursery where a biological control breakdown was observed. The RFLP analysis of 16S + IGS regions showed that pAgK84 was transferred from the antagonist to virulent and avirulent soil agrobacteria belonging to different ribotypes. Pathogenic transconjugants, inoculated on GF677 rootstocks, were not controlled in vivo by K84 and stably maintained pTi and pAgK84 in the bacterial cells for at least one year. At the end of a biocontrol trial, new transconjugant tumorigenic agrobacteria originated by the transfer of pAgK84 to the pathogen. Virulent and avirulent transconjugants may represent a real threat for biological control by K84 strain since all of them produced agrocin and were insensitive to it. Survival in soil of these populations could make the future application of K84 ineffective. 相似文献
20.
由致病性根癌土壤杆菌Agrobacterium spp.侵染引起的根癌病对山东及我国其他省份的樱桃、桃及其他果树生产造成严重的影响.土壤杆菌Agrobacterium rhizogenes K1026在澳大利亚已制成生防菌剂并在全球多个国家实现商品化,但在我国果树育苗和生产行业中还未得到广泛应用.本文从山东樱桃和桃树根癌组织及感病土壤中分别分离到100余株致病性土壤杆菌,经鉴定均属于生物Ⅱ型土壤杆菌;利用双层平板抑菌试验,检测了37株病原菌对菌株K1026的敏感性,结果显示,所有菌株均对K1026产生的抗生物质敏感,可以在Stonier,s培养基上产生5种以上不同类型的抑菌圈;胡萝卜切片试验显示,菌株K1026可完全抑制37株病原菌对胡萝卜的致瘤活性.上述结果为土壤杆菌K1026用于山东省樱桃及桃树根癌病的生物防治奠定了基础. 相似文献