首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Bacterial spot of tomato (Solanum lycopersicum) is caused by four species of Xanthomonas. The disease causes significant yield losses and a reduction in fruit quality. Physiological races have been described with tomato race 3 (T3) corresponding to strains of Xanthomonas perforans. The breeding line Hawaii 7981 (hereafter H7981) shows a hypersensitive reaction (HR) to race T3 strains conditioned by the interaction of the host resistance locus Xv3 and the bacterial effector avrXv3. The Xv3 gene is required for H7981-derived resistance to be effective under field conditions, though its expression is subject to genetic background. The segregation of HR in F(2) populations derived from H7981 crossed to processing tomato parents OH88119 and OH7870 was studied in 331 progeny, with the two independent crosses providing validation. We screened 453 simple-sequence repeat, insertion/deletion, and single-nucleotide polymorphism markers and identified 44 polymorphic markers each for the OH88119 and OH7870 populations covering 84.6 and 73.3% of the genome, respectively, within 20 centimorgans (cM). Marker-trait analysis using all polymorphic markers demonstrated that Xv3-mediated resistance maps to chromosome 11 in the two independent crosses. Allelism tests were conducted in crosses between lines carrying Xv3 derived from H7981, Rx-4 derived from plant introduction (PI) 128216, and resistance derived from PI 126932. These allelism tests suggested that the loci conditioning HR to race T3 strains are linked within 0.1 cM, are allelic, or are the same gene.  相似文献   

2.
ABSTRACT Until recently, tomato race 1 (T1) of Xanthomonas campestris pv. vesicatoria was the only race causing bacterial spot of tomato in Florida. In 1991, tomato race 3 (T3) was first identified in 3 of 13 tomato production fields surveyed. By 1994, T3 was observed in 21 of 28 fields and was the only race identified in 14 fields. In field studies, tomato genotypes with resistance to either T1 or T3 or susceptibility to both were co-inoculated with strains of both races. Lesions on 10 plants in each of three replications for each genotype were sampled three times during the experiment; bacterial isolations were made from each lesion, and tomato race identifications were made for each strain. At the third sampling date, T3 was isolated from 97% of the lesions on the susceptible genotype Walter and the T1-resistant genotype Hawaii 7998, while T3 was isolated from 23% of the lesions and T1 from the remaining 77% on the T3-resistant genotypes PI 128216 and PI 126932. In surface population studies done in growth rooms, suspensions of T1 and T3 were applied alone and in combination to the leaf surfaces of susceptible and resistant genotypes. T1 populations were reduced more than 10-fold when applied in combination with T3, compared with populations that developed when T1 was applied alone. T3 populations were not affected when applied in combination with a T1 strain. In greenhouse studies with the T3-resistant genotype Hawaii 7981, disease was significantly reduced in plants inoculated with T3 in combination with T1, compared with plants inoculated with T1 alone. These results clearly demonstrate the competitive nature of T3 in the presence of T1 and help explain the emergence of T3 as a prevalent race in Florida.  相似文献   

3.
ABSTRACT We used molecular markers to identify quantitative trait loci (QTL) that confer resistance in the field to Xanthomonas campestris pv. vesicatoria race T1, a causal agent of bacterial spot of tomato. An F(2) population derived from a cross between Hawaii 7998 (H 7998) and an elite breeding line, Ohio 88119, was used for the initial identification of an association between molecular markers and resistance as measured by bacterial populations in individual plants in the greenhouse. Polymorphism in this cross between a Lycopersicon esculentum donor of resistance and an elite L. esculentum parent was limited. The targeted use of a core set of 148 polymerase chain reaction-based markers that were identified as polymorphic in L. esculentum x L. esculentum crosses resulted in the identification of 37 markers that were polymorphic for the cross of interest. Previous studies using an H 7998 x L. pennellii wide cross implicated three loci, Rx1, Rx2, and Rx3, in the hypersensitive response to T1 strains. Markers that we identified were linked to the Rx1 and Rx3 loci, but no markers were identified in the region of chromosome 1 where Rx2 is located. Single marker-trait analysis suggested that chromosome 5, near the Rx3 locus, contributed to reduced bacterial populations in lines carrying the locus from H 7998. The locus on chromosome 5 explained 25% of the phenotypic variation in bacterial populations developing in infected plants. An advanced backcross population and subsequent inbred backcross lines developed using Ohio 88119 as a recurrent parent were used to confirm QTL associations detected in the F(2) population. Markers on chromosome 5 explained 41% of the phenotypic variation for resistance in replicated field trials. In contrast, the Rx1 locus on chromosome 1 did not play a role in resistance to X. campestris pv. vesicatoria race T1 strains as measured by bacterial populations in the greenhouse or symptoms in the field. A locus from H 7998 on chromosome 4 was associated with susceptibility to disease and explained 11% of the total phenotypic variation. Additional variation in resistance was explained by plant maturity (6%), with early maturing families expressing lower levels of resistance, and plant habit (6%), with indeterminate plants displaying more resistance. The markers linked to Rx3 will be useful in selection for resistance in elite x elite crosses.  相似文献   

4.
Bacterial leaf spot incited by Xanthomonas campestris pv. mori is a devastating foliar disease of mulberry reported globally. Host plant resistance is the most sustainable and economic control measure but so far unexplored. Highly heterozygous plant behaviour and scant genetic information of bacterial leaf spot resistance limits a targetted breeding approach in mulberry. In the present research eight pseudo-F2(F1)full-sib progenies derived from selected resistant and susceptible sources were evaluated symptomatically for bacterial leaf spot resistance under natural disease occurrence in 2008 and 2009. Significant variation for bacterial leaf spot resistance was observed in the parents and progenies. Broad sense heritability estimate (0.9) indicates that selection of resistant genotypes can be useful for exploitation in future advanced breeding programs for mulberry. High narrow sense heritability estimates (0.76)[2008] and (0.79)[2009] suggest additive gene effects for the disease resistant trait. The continuous frequency distribution of diseases severity across the progenies indicates that bacterial leaf spot resistance in mulberry may be inherited quantitatively.  相似文献   

5.
The composition and structure of pectic cell wall polysaccharides of stem sections were investigated in healthy and Ralstonia solanacearum-inoculated tomato genotypes L390 and Hawaii 7996, susceptible and resistant to bacterial wilt, respectively, by immunohistochemical analysis. Constitutive differences between genotypes manifested in methyl-ester distribution of homogalacturonan (HG), arabinan and galactan side chain composition of rhamnogalacturonan I (RG I) and arabinogalactan-protein (AGP) in the xylem parenchyma and in vessel cell walls. After inoculation increased labeling was observed with all the antibodies (JIM5, JIM7, LM2, LM5, LM6, LM7) specific for HG, RG I and AGP epitopes, in the xylem parenchyma and around xylem vessels of stem sections of L390, but not of Hawaii 7996. Also vessel cell walls were stronger stained after inoculation in L390, particularly for the non-blockwise de-esterification of HG, possibly indicating for the first time the non-blockwise action pattern of bacterial pectin methyl esterase. In genotype Hawaii 7996 a reaction to inoculation was observed only in vessel walls, with a significantly increased number of stained vessels—five- and nine-fold for arabinan and galactan epitopes of RG I, respectively. Differences in xylem cell wall structure may play a role as a constitutive resistance mechanism in the multigenic resistance of tomato against bacterial wilt, while changes after inoculation may contribute to induced basal resistance on cell wall level.  相似文献   

6.
Acibenzolar-S-methyl (ASM), a plant activator known to induce plant resistance, has been used as foliar sprays to manage several plant diseases including bacterial spot on tomato caused by four distinct Xanthomonas species. This study aimed to investigate the effects of soil application rates of ASM on bacterial spot of tomato and the expression levels of the two pathogenesis-related (PR) genes, PR1a and PR1b, in leaf tissues. Tomato seedlings were leaf-applied with ASM at 18.8 mg/l corresponding to the labeled rate, soil-applied with ASM at 0.84 and 10 mg/l, and sprayed with water served as an untreated control. The soil application of ASM at 10 mg/l consistently reduced the final disease severity and disease progress compared to the untreated control in four growth chamber experiments, whereas the soil application of ASM at 0.84 mg/l and foliar spray of ASM significantly reduced the final disease severity and area under disease progress curve (AUDPC) in three out of the four experiments. The expression levels of PR1a and PR1b in the leaf tissues were significantly induced by both soil and foliar applications of ASM. In addition, field trial results suggested that the soil applications of ASM at 10 mg/l markedly reduced disease progress compared to the control and copper standard. Although the control efficiency of soil applications of ASM depends on rates used, this study suggests that ASM can be used as soil applications to induce tomato resistance against bacterial spot.  相似文献   

7.
In this study, we investigated the ability of DL-3-aminobutyric acid (BABA) to protect tomato against bacterial wilt caused by Ralstonia solanacearum. This was combined with studies of accumulation of total phenolic compounds, free and total salicylic acid (SA), and activity of enzymes related to plant defence, i.e., polyphenol oxidase (PPO) and catalase (CAT). Under greenhouse conditions, tomato plants pre-treated by soil drenching with BABA profoundly reduced disease severity of bacterial wilt compared to plants receiving a soil drench with water. Thus, BABA reduced leaf wilting index by 75.3 % and vascular browning index by 69.9 %, without any in vitro inhibitory activity on the pathogen. BABA treatment significantly reduced the population of R. solanacearum in stems of tomato plants and additionally also significantly increased both fresh and dry weight of roots and shoots of tomato plants compared with the inoculated control. Application of BABA resulted in a high increase in PPO activity both in plants with and without inoculation. Compared to water-treated plants, treatment with BABA also induced a significant increase of total phenolic compounds as well as of free and total SA in leaves of both inoculated and non-inoculated tomato plants at all sampling times. CAT activity decreased in tomato plants treated with BABA in comparison with the water-treated control plants and the decrease in activity correlated with an increasing total SA accumulation. These findings suggest that BABA treatment resulted in induction of resistance to bacterial wilt in tomato.  相似文献   

8.
Cercospora leaf spot (CLS) poses a high economic risk to sugar beet production due to its potential to greatly reduce yield and quality. For successful integrated management of CLS, rapid and accurate identification of the disease is essential. Diagnosis on the basis of typical visual symptoms is often compromised by the inability to differentiate CLS symptoms from similar symptoms caused by other foliar pathogens of varying significance, or from abiotic stress. An automated detection and classification of CLS and other leaf diseases, enabling a reliable basis for decisions in disease control, would be an alternative to visual as well as molecular and serological methods. This paper presents an algorithm based on a RGB‐image database captured with smartphone cameras for the identification of sugar beet leaf diseases. This tool combines image acquisition and segmentation on the smartphone and advanced image data processing on a server, based on texture features using colour, intensity and gradient values. The diseases are classified using a support vector machine with radial basis function kernel. The algorithm is suitable for binary‐class and multi‐class classification approaches, i.e. the separation between diseased and non‐diseased, and the differentiation among leaf diseases and non‐infected tissue. The classification accuracy for the differentiation of CLS, ramularia leaf spot, phoma leaf spot, beet rust and bacterial blight was 82%, better than that of sugar beet experts classifying diseases from images. However, the technology has not been tested by practitioners. This tool can be adapted to other crops and their diseases and may contribute to improved decision‐making in integrated disease control.  相似文献   

9.
The distribution and multiplication of Ralstonia solanacearum in tomato plants of 11 resistant cultivars derived from different genetic sources and susceptible cultivar Ponderosa were examined. Bacterial multiplication in stems of resistant tomato plants was suppressed owing to the limitation of pathogen movement from the protoxylem or the primary xylem to other xylem tissues. The limitation was most conspicuous in Hawaii 7996. Grafting experiments indicated that the percentage of wilting of Ponderosa scions was less on Hawaii 7996 rootstocks than that on the most resistant rootstock (LS-89) used in Japan. Hawaii 7996 could be an alternative genetic source for breeding for resistance to bacterial wilt.  相似文献   

10.
In plant disease management, surfactants are generally used in combination with pesticides to facilitate delivery of the pesticide chemicals to the target sites in plants, vectors, or pathogens. Their intended use is rarely for direct effect on plant pathogens. However, trends in recent studies have revealed an appreciable increase in their use for direct management of plant diseases. In this paper, we briefly review the progress made in the use of surfactants for disease management, as adjuvants and when applied for direct effect. We carried out experiments to evaluate the effect of selected synthetic surfactants (Cohere, Kinetic, Silwet-77, and Induce) on powdery mildew in squash and bacterial spot in tomato. Results from this study showed that the effect of surfactants on these pathogens is dependent on the type of plant pathogen or disease. All tested surfactants exhibited in vitro bactericidal activity against Xanthomonas perforans, a causal pathogen of bacterial spot of tomato. In the greenhouse, Cohere significantly reduced disease severity of powdery mildew in squash compared to the untreated control. Cohere also showed promise in field trials against bacterial spot of tomato, but the other surfactants tested promoted this disease. Our studies demonstrate the importance of evaluating surfactants for their use in management of plant diseases both for direct effect and as adjuvants in tank mix.  相似文献   

11.
The objectives of this study were to assess the reliability and accuracy of visual methods used to quantify the severity of bacterial spot (Xanthomonas arboricola pv. pruni) symptoms and evaluate the effects of rater experience on the quality of disease estimates. Three cohorts of raters differing in experience with disease assessment rated three sets of peach or nectarine leaves (n ≥ 103; disease severity levels from 0% to 100%) by direct estimation of percentage leaf area with symptoms. Four of the experienced raters also rated the leaves using a 1–7 interval scale. Actual disease severity on the leaves was obtained with the APS assess image analysis software. Equivalence tests based on a bootstrap analysis were used to compare the rating scale and direct estimation methods, and to evaluate the effects of rater experience, computer training and human instruction on accuracy and reliability of disease estimates. In concordance analysis of continuous variables, with data from scale converted to percentage, the direct estimation method resulted in more accurate and reliable estimates than the interval scale. Analysing the scale data without conversion to percentage improved the concordance statistics for the scale but not sufficiently to match the direct estimation method. Accuracy was affected more by rater experience and intrinsic ability than reliability. Instruction on disease symptoms resulted in the largest improvement in estimates from inexperienced raters. Accurate and reliable direct estimation of bacterial spot severity on peach and nectarine can be made by raters with varying levels of experience provided they receive sufficient instruction.  相似文献   

12.
Xanthomonas perforans is the causal agent of bacterial spot, one of the most devastating diseases of tomato that results in considerable yield losses worldwide. Rutin, as a polyphenolic substance, was used to induce resistance in tomato against X. perforans. Rutin at concentration of 2 mM had ability to reduce the disease severity of bacterial spot. On the other hand, 2 mM rutin had no antibacterial activity in vitro. Expression profiling of pathogenesis-related gene 5 (PR-5), Phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) was probed during the enhanced resistance by rutin. Pretreatment with rutin (rutin/ X. perforans) led to induction of PR-5, PAL and LOX compared to controls (water/ X. perforans). Our results suggest that rutin-induced resistance against X. perforans in tomato might be mediated through stimulation of some defense genes such as PR-5, PAL and LOX.  相似文献   

13.
ABSTRACT Expression of a foreign gene to enhance plant disease resistance to bacterial pathogens is a favorable strategy. It has been demonstrated that expressing sweet pepper ferredoxin-I protein (PFLP) in transgenic plants can enhance disease resistance to bacterial pathogens that infect leaf tissue. In this study, PFLP was applied to protect tomato (Lycopersicon esculentum cv. cherry Cln1558a) from the root-infecting pathogen, Ralstonia solanacearum. Independent R. solanacearum resistant T(1) lines were selected and bred to produce homozygous T(2) generations. Selected T(2) transgenic lines 24-18-7 and 26-2-1a, which showed high expression levels of PFLP in root tissue, were resistant to disease caused by R. solanacearum. In contrast, the transgenic line 23-17-1b and nontransgenic tomato, which showed low expression levels of PFLP in root tissue, were not resistant to R. solanacearum infection. The expansion of R. solanacearum populations in stem tissue of transgenic tomato line 24-18-7 was limited compared with the nontransgenic tomato Cln1558a. Using a detached leaf assay, transgenic line 24-18-7 was also resistant to maceration caused by E. carotovora subsp. carotovora; however, resistance to E. carotovora subsp. carotovora was less apparent in transgenic lines 26-2-1a and 23-17-1b. These results demonstrate that PFLP is able to enhance disease resistance at different levels to bacterial pathogens in individual tissue of transgenic tomato.  相似文献   

14.
A 2‐year comprehensive field survey was conducted across major tomato‐growing areas of Iran. Two hundred and thirty‐four tomato fields and six tomato‐producing greenhouses were surveyed for the potential presence of bacterial spot disease. Five hundred and ninety‐six tomato samples with and without symptoms were analysed. While Xanthomonas spp. were found in association with tomato plants both with and without symptoms from five surveyed counties, the bacterial spot disease was observed only in plants from three of them. Only strains isolated from plants with symptoms induced disease symptoms on tomato, while those isolated from symptomless plants caused symptoms only on cabbage and common bean. None of the isolates caused disease symptoms on pepper and eggplant. Phylogenetic analysis showed that X. perforans is the causal agent of tomato bacterial spot in Iran, although X. campestris and X. axonopodis were also associated with symptomless tomato plants. All X. perforans isolates in this study were sensitive to streptomycin, copper sulphate and copper oxychloride at concentrations of 50 mg L?1, 200 mg L?1 and 0.8 g L?1, respectively. Unlike the type strain of X. perforans, isolates in this study did not produce bacteriocin against other Xanthomonas spp., nor were they detected using the usual species‐specific primer pair Bs‐XpF/Bs‐XpR. This suggests an atypical nature of X. perforans strains in Iran, which leads to the hypothesis that X. perforans strains in Iran may have a separate origin to those causing disease epidemics elsewhere. The aggregated dispersal pattern of the diseased tomato fields signifies the seedborne introduction of the pathogen into the country.  相似文献   

15.
Twenty tomato (Solanum lycopersicon) cultivars were screened for resistance against bacterial spot disease incited byXanthomonas axonopodis pv.vesicatoria under field conditions with and without pathogen infection. Screening was done by artificially inoculating aX. axonopodis pv.vesicatoria suspension to 4-week-old tomato seedlings and observing them for typical symptoms of the disease. Seedlings were categorized into highly resistant, resistant, susceptible and highly susceptible cultivars on the basis of disease incidence. Tomato cultivars were screened for defense-related enzymes, total phenols and lignin contents. The temporal patterns of all these enzymes were estimated with a moderately susceptible tomato cultivar. Native PAGE analysis of both peroxidase (POX) and polyphenol oxidase (PPO) was carried out for the time course of enzyme activities and also by selecting three different tomato cultivars, following infection with the pathogen. Based on the inducible amounts of these enzymes upon pathogen infection, the tomato cultivars were correlated with the disease incidence under field conditions. A significant (P≤0.05) correlation was observed between the degree of host resistance and the enzyme levels. In highly resistant tomato cultivars the enzyme levels, total phenols and lignin contents were increased in comparison with highly susceptible tomato cultivars. Isoform analysis of POX and PPO enzymes indicated a clear difference between resistant and susceptible tomato cultivars in the number of isoforms and also in the intensity of each isoform in the presence of pathogen infection. The possible regulation of defense-related enzymes in imparting host resistance is discussed. http://www.phytoparasitica.org posting March 11, 2008.  相似文献   

16.
Xie W  Yu K  Pauls KP  Navabi A 《Phytopathology》2012,102(4):434-442
The effectiveness of image analysis (IA) compared with an ordinal visual scale, for quantitative measurement of disease severity, its application in quantitative genetic studies, and its effect on the estimates of genetic parameters were investigated. Studies were performed using eight backcross-derived families of common bean (Phaseolus vulgaris) (n = 172) segregating for the molecular marker SU91, known to be associated with a quantitative trait locus (QTL) for resistance to common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. fuscans subsp. fuscans. Even though both IA and visual assessments were highly repeatable, IA was more sensitive in detecting quantitative differences between bean genotypes. The CBB phenotypic difference between the two SU91 genotypic groups was consistently more than fivefold for IA assessments but generally only two- to threefold for visual assessments. Results suggest that the visual assessment results in overestimation of the effect of QTL in genetic studies. This may have been caused by lack of additivity and uneven intervals of the visual scale. Although visual assessment of disease severity is a useful tool for general selection in breeding programs, assessments using IA may be more suitable for phenotypic evaluations in quantitative genetic studies involving CBB resistance as well as other foliar diseases.  相似文献   

17.
A total of 252 wild Solanum accessions and one population of 49 introgression lines of LA716 were screened for resistance to a race 1/biovar 4/phylotype I strain Pss186 of Ralstonia solanacearum. Most wild tomato accessions were highly susceptible. However, five accessions of S. pennellii, i.e. LA1943, LA716, LA1656, LA1732 and TL01845 were resistant to strain Pss186. These accessions were then challenged against two other race 1/phylotpye I strains Pss4 and Pss190, which were more aggressive. All the five S. pennellii accessions were susceptible to Pss4, but displayed high to moderate resistance to Pss190 with a percentage of wilted plants ranging from 0% to 60%. Pss190 is an aggressive strain that made a resistant tomato line Hawaii 7996 susceptible. Thus, the results found in this study provide evidence of the presence of strain-specific resistance. LA3501, which has an introgression segment on chromosome 6, was found to be resistant to Pss186 among the screened introgression lines. This confirms the importance of resistance trait loci on chromosome 6 that have been identified by other studies. This is the first report of S. pennellii being resistant to bacterial wilt. These new resistant sources will provide breeders with more resources to breed for stable resistance to bacterial wilt of tomato.  相似文献   

18.
Using tomato seedlings, the plant defence activator acibenzolar-S-methyl (benzo-[1,2,3]-thiadiazole-7-carbothioic acid-S-methyl ester, ASM; Bion 50 WG) was assayed for its ability to induce resistance against Clavibacter michiganensis ssp. michiganensis , the causal agent of bacterial canker of tomato. In ASM-pretreated plants, reduction in disease severity (up to 76·3%) was correlated with lower bacterial growth (up to 68·2% lower) during the time course of infection. To understand the possible mechanism of action of ASM, alterations in the activities of peroxidase (POX) and chitinase were assessed as markers of resistance. The enhanced resistance of ASM-treated plants was associated with significant increases in the activities of POX and chitinase  相似文献   

19.
The objective of this study was to screen wild and domesticated tomatoes for resistance to Tomato yellow leaf curl virus, Israel (TYLCV-Is) and Tomato leaf curl virus from Bangalore isolate 4, India (ToLCV-[Ban4]) to find sources of resistance to both viruses. A total of 34 tomato genotypes resistant/tolerant to TYLCV-Is were screened for resistance to ToLCV-[Ban4] under glasshouse and field conditions at the University of Agricultural Sciences, Bangalore, India. Resistance was assessed by criteria like disease incidence, symptom severity and squash-blot hybridization. All the tomato genotypes inoculated with ToLCV-[Ban4] by the whitefly vector Bemisia tabaci (Gennadius) produced disease symptoms. In some plants of the lines 902 and 910, however, the virus was not detected by hybridization. The tomato genotypes susceptible to ToLCV-[Ban4] by whitefly-mediated inoculation were also found susceptible to the virus under field conditions. However, there were substantial differences between genotypes in disease incidence, spread, symptom severity and crop yield. Despite early disease incidence, many genotypes produced substantially higher yields than the local hybrid, Avinash-2. Sixteen tomato genotypes from India resistant/tolerant to ToLCV-[Ban4] were also tested for TYLCV-Is resistance at the Hebrew University of Jerusalem, Rehovot, Israel. Accessions of wild species, Lycopersicon hirsutum LA 1777 and PI 390659 were the best sources of resistance to both viruses. Lines 902 and 910, which were, resistant to TYLCV-Is were only tolerant to ToLCV-[Ban4] and accession Lycopersicon peruvianum CMV Sel. INRA, resistant to ToLCV-[Ban4], was only tolerant to TYLCV-Is. Implications of using the resistant lines in breeding programme is discussed.  相似文献   

20.
Inoculation of tomato seeds with the plant growth-promoting bacterium Azospirillum brasilense, or spraying tomato foliage with A. brasilense, streptomycin sulfate, or commercial copper bactericides, separately, before or after inoculation with Pseudomonas syringae pv. tomato, the casual agent of bacterial speck of tomato, had no lasting effect on disease severity or on plant height and dry weight. Seed inoculation with A. brasilense combined with a single streptomycin foliar treatment and two foliar bactericide applications at 5-day intervals (a third or less of the recommended commercial dose) reduced disease severity in tomato seedlings by over 90% after 4 weeks, and significantly slowed disease development under mist conditions. A. brasilense did not induce significant systemic resistance against the pathogen although the level of salicylic acid increased in inoculated plants. Treatment of tomato seeds that were artificially inoculated with P. syringae pv. tomato, with a combination of mild chemo-thermal treatment, A. brasilense seed inoculation, and later, a single foliar application of a copper bactericide, nearly eliminated bacterial leaf speck even when the plants were grown under mist for 6 weeks. This study shows that a combination of otherwise ineffective disease management tactics, when applied in concert, can reduce bacterial speck intensity in tomatoes under mist conditions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号