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1.
Takashi Hanagasaki Maki Yamashiro Kozo Gima Tetsuya Takushi Shinji Kawano 《Plant pathology》2021,70(4):932-942
Since 2002, papaya black rot has been spreading over several islands of Okinawa Prefecture, Japan. To devise a prevention strategy for the disease, microbiological research on the pathogen was conducted. Twelve strains were isolated from papaya infected with black rot showing symptoms such as water-soaked lesions on stems and petioles, black spots on fruits, and rotted leaves turning yellow with necrotic spots. Through Koch's postulates, we confirmed that the isolated strains caused papaya black rot. Bacteriological assays showed that the strains have characteristics different from the type strains of Erwinia mallotivora, E. papayae, and E. psidii. Moreover, 16S rDNA sequence similarity searches showed that the isolated strains had less than 98.6% similarity with type strains. Additionally, phylogenetic analysis of 16S rDNA sequences suggested that the isolated strains were possibly a novel species belonging to the genus Erwinia, as the strains formed an independent cluster and had low sequence similarity with the type strains. Earlier studies indicated that papaya black rot is caused by E. cypripedii. Therefore, we propose to add the Erwinia sp. isolated in this study to the list of papaya black rot pathogens. 相似文献
2.
Alba Valéria da Silva Pereira Ricardo Brainer Martins Sami Jorge Michereff Marcelo Bezerra da Silva Marcos Paz Saraiva Camara 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(4):489-498
Stem rot caused by Lasiodiplodia theobromae is an important postharvest disease of papaya in Brazil, responsible for reducing the quality and quantity of fruits. Fungicide
use is one of the main disease management measures. However, there are no estimates available of pathogen sensitivity to commonly
employed fungicides. Therefore, the EC50 from 120 isolates of L. theobromae from northeastern Brazil, representative of six populations of the pathogen, was estimated in vitro for fungicides of the
methyl benzimidazole carbamates—MBC (benomyl and thiabendazole) and demethylation-inhibiting—DMI (imazalil, prochloraz, tebuconazole)
groups. Mycelial growth on fungicide-free media and virulence on papaya fruits of the MBC-sensitive and non-sensitive isolates
were compared. For MBCs, 8.4% of isolates were non-sensitive to fungicides. For the remaining 91.6%, the mean EC50 ranged from 0.002 to 0.13 μg ml−1 and 0.36 to 1.27 μg ml−1 for benomyl and thiabendazole, respectively. For DMIs, the mean EC50 range for imazalil was 0.001 to 2.27 μg ml−1, 0.04 to 1.75 μg ml−1 for prochloraz, and 0.14 to 4.05 μg ml−1 for tebuconazole. The EC50 values of non-sensitive isolates were significantly (P≤0.05) higher those for the sensitive isolates for each of the DMI fungicides. Differences (P≤0.05) were found in the levels of sensitivity to DMI fungicides among the isolate populations associated with orchards. The
populations from two orchards were less sensitive to DMIs. No solid evidence was found for fitness costs relating to MBC non-sensitive
isolates because mycelial growth in fungicide-free media and virulence on papaya fruits were similar to those of sensitive
isolates. 相似文献
3.
Alan T. Dyer Robert H. Johnston Andrew C. Hogg Jeffrey A. Johnston 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(3):387-395
Fusarium species involved in the Fusarium crown rot (FCR) complex affect wheat in every stage of development from seedling to grain
fill. This study was designed to compare the aggressiveness of the FCR complex members including F. culmorum, F. pseudograminearum and F. graminearum in causing seedling blight, decreased plant vigour and crown rot. To assess their relative pathogenicity, two hard red spring
wheat cultivars and two durum wheat cultivars were inoculated in the field with five isolates from each of the three species
for two years. Significant differences in patterns of pathogenicity were identified. In particular, F. culmorum caused greater seedling blight while F. pseudograminearum and F. graminearum caused greater crown rot. Greatest yield reductions were caused by F. pseudograminearum. Cultivar differences were identified with respect to seedling disease and late season crown rot. No interactions were identified
between cultivar performance and isolates or species with which they were challenged. 相似文献
4.
Masafumi SHIMIZU Yoshiko NAKAGAWA Yukio SATO Tamotsu FURUMAI Yasuhiro IGARASHI Hiroyasu ONAKA Ryuji YOSHIDA Hitoshi KUNOH 《Journal of General Plant Pathology》2000,66(4):360-366
To survey endophytic actinomycetes as potential biocontrol agents against fungal diseases of rhododendron, young plants of
rhododendron were surface-sterilized for use as an isolation source. Nine, six and two isolates, with distinguishing characteristics
based on the macroscopic appearance of colonies, were obtained from roots, stems and leaves, respectively, suggesting that
various species of actinomycetes grow in the respective organs of this plant as symbionts or parasites. On an agar medium,
only isolate R-5 commonly formed a clear growth-inhibition zone against two major fungal pathogens of rhododendron, Phytophthora cinnamomi and Pestalotiopsis sydowiana, indicating that this isolate can produce antifungal material(s). Acetone extracts of a liquid culture of R-5 had a broad antimicrobial
spectrum against Gram-positive bacteria, yeast and filamentous fungi. Isolate R-5 was identified as a Streptomyces sp. based on morphological, physiological and chemotaxonomical characteristics. The present results indicate that isolate
R-5 is a suitable candidate for the biocontrol of diseases of rhododendron.
Received 25 March 2000/ Accepted in revised form 18 May 2000 相似文献
5.
Tomio NISHIMURA Akane MEGURO Sachiko HASEGAWA Yoshiko NAKAGAWA Masafumi SHIMIZU Hitoshi KUNOH 《Journal of General Plant Pathology》2002,68(4):390-397
To survey endophytic actinomycetes as potential biocontrol agents against fungal diseases of mountain laurel, young plants
of mountain laurel (Kalmia latifolia L.) were used as an isolation source. From a total of 73 actinomycetes isolates obtained from leaves, stems and roots of test
plants, Streptomyces sp. AOK-30 was selected, because i) it had a broad and intense antimicrobial spectrum against various yeasts and fungal pathogens
of Ericaceae, ii) it grew on the multiplication and rooting media for tissue culture for this plant, and iii) the tissue-cultured
seedlings that had been treated with this isolate became resistant to Pestalotia disease without any adverse growth effects
such as malformation, dwarfing, discolorization and defoliation. This isolate was identified as Streptomyces sp., based on cultural, physiological and morphological characteristics. The present results indicate that isolate AOK-30
is a potential biocontrol agent against diseases of mountain laurel.
Received 10 September 2002/ Accepted in revised form 22 November 2002 相似文献
6.
Khaled A. El-Tarabily Giles E. St. J. Hardy Krishnapillai Sivasithamparam 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(4):527-539
In the current study, the performance of three endophytic actinomycetes identified as Actinoplanes campanulatus, Micromonospora chalcea and Streptomyces spiralis previously shown to reduce seedling damping-off, and root and crown rots of mature cucumber (Cucumis sativus) caused by Pythium aphanidermatum in pots under greenhouse conditions were further evaluated to determine their potential as biological control agents and
as plant growth promoters in the field under the conditions of commercial production of cucumbers in the United Arab Emirates
(UAE). When applied individually or in combination to cucumber seedlings, the three isolates significantly promoted plant
growth and yield and reduced seedling damping-off and root and crown rots of mature cucumber plants. Individually the performance
level of S. spiralis was relatively the best followed by A. campanulatus and then by M. chalcea. The three isolates (which were not inhibitory to each other) performed better, both as biological control agents as well
as plant growth promoters, when applied together than when they were inoculated individually. The ability of these three isolates
to colonize the internal tissues of roots, stems and leaves under field conditions, and to persist up to 8 weeks after seedling
inoculation, showed that they can easily adapt to an endophytic habit systemically within healthy cucumber plants. As the
three endophytic actinomycete isolates also colonized the rhizosphere and showed outstanding rhizosphere competency it is
clear that they are facultative and not obligate endophytes. The success with the three inoculants indicated that they could
well be used in place of the fungicide metalaxyl which is currently recommended for the management of Pythium diseases in the UAE. This is the first successful field use of endophytic actinomycetes as promising plant growth promoters
and biological control agents against Pythium diseases of cucumber. 相似文献
7.
Hassan Etesami Hossein Ali Alikhani 《European journal of plant pathology / European Foundation for Plant Pathology》2017,147(1):7-14
Gram-positive bacteria isolated from the rhizosphere and inside the roots of rice were characterized for plant growth promoting (PGP) traits and antifungal activity against some rice plant pathogenic fungi of rice. The results showed the endophytic and rhizosphere isolates had different PGP traits and antifungal activity. Only one rhizosphere isolate and one endophytic isolate showed highly inhibitory effects against the mycelial growth of all fungal rice pathogens tested in this study. The best bacterial isolates, based on multiple PGP traits and inhibitory effects against the mycelial growth of all fungal rice pathogens, were identified. Based on biochemical tests and by comparison of 16S rDNA sequences, the endophytic isolate REN3 and the rhizosphere isolate REN4 were closely related to Bacillus cereus and Bacillus mojavensis respectively. The broad-spectrum antifungal strains, the REN3 and REN4 isolates analyzed here, exert multiple PGP and antagonistic activity and represent an excellent option to be used as either potent bio-promoting or bio-control agents in rice under in vitro conditions. This application may help to minimize dependence on pesticides, which have adverse effects on the environment, finally leading to have sustainable environments. In conclusion, the results of antifungal activity showed rice harbors bacteria with a good potential in biocontrol of rice fungal pathogens. 相似文献
8.
9.
Susan Asghari Behrouz Harighi Morahem Ashengroph Christophe Clement Aziz Aziz Qassim Esmaeel Essaid Ait Barka 《Plant pathology》2020,69(5):827-837
Crown gall disease of grapevine, caused by Agrobacterium tumefaciens, often results in severe economic loss to grape production worldwide. This study demonstrated the ability of the endophytic bacteria Pseudomonas sp. Sn48 and Pantoea sp. Sa14 isolated from domesticated and wild grapevines to induce resistance in both above- and belowground tissues of grapevines infected with A. tumefaciens. Our results provide evidence that both strains can colonize roots and/or shoots. We showed that the strains Pseudomonas sp. Sn48 and Pantoea sp. Sa14 are capable of inducing stilbenic phytoalexin production in grapevine tissues and to further prime plantlets for enhanced phytoalexin production after A. tumefaciens inoculation. We also showed that in the majority of treatments, polyamine accumulation remained unchanged or slightly increased in plantlets treated with Pseudomonas sp. Sn48 and Pantoea sp. Sa14 compared with the control. Our findings indicated that the levels of polyamines remain unchanged or significantly decrease in plantlets treated with endophytic bacteria after A. tumefaciens challenge compared to the control and plantlets treated with individual endophytic bacterial strains. PR1, PR2, and PR4 gene expression levels of plantlets treated with Pseudomonas sp. Sn48 and Pantoea sp. Sa14 significantly increased after A. tumefaciens inoculation. The findings revealed the efficacy of the selected endophytic bacteria in triggering grapevine resistance against A. tumefaciens and the possible use of these strains as an alternative to chemical control methods in grapevine crown gall disease management. 相似文献
10.
Rômulo Diniz Cavalcante Waléria Guerreiro Lima Ricardo Brainer Martins Juan Manuel Tovar-Pedraza Sami Jorge Michereff Marcos Paz Saraiva Câmara 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(2):251-259
Stem-end rot, caused by Lasiodiplodia theobromae, is an important postharvest disease of papaya in Brazil. The use of fungicides is one of the main disease management measures. However, there are no data available on the sensitivity of L. theobromae to thiophanate methyl (methyl benzimidazole carbamate), the most common fungicide used in papaya orchards in northeastern Brazil. Thus, the effective concentration that results in 50 % of mycelial growth inhibition (EC50) of 109 isolates, representing five populations of the pathogen was estimated in vitro. Seven components of fitness were measured for the 10 isolates with lower and high values of EC50. Of the 109 isolates, 20.2 % were resistant to the fungicide with EC50 values greater than 300 μg ml?1, whereas the remaining 79.8 % were sensitive with an average EC50 of 1.87 μg ml?1. The EC50 values for the resistant isolates were significantly (P?≤?0.05) higher than those for the sensitive isolates. When the fitness components were evaluated, only in relation to the spore production was significant difference among sensitive and resistant isolates, and resistant isolates showed sporulation capacity significantly lower than the S isolates, indicating a fitness cost. 相似文献
11.
Fusarium culmorum (Fc) and F. graminearum (Fg) belong to the predominant causal agents of fusarium crown and root rot (FCR) in wheat. While many studies have been done to investigate crown rot, including stem base infection, root colonization and mycotoxin production associated with root rot is not well understood. In this study the impact of mycotoxins on the colonization of wheat roots and stem bases was analysed by using Fc and Fg isolates that varied in both quantity and types of trichothecenes they produce. Seedling inoculations in growth chambers with a high deoxynivalenol (DON)- and 3-acetyldeoxynivalenol (3ADON)-producing isolate led to more severe symptoms and 20-times greater colonization of the stem base, as measured by Fc DNA accumulation, than isolates that produced less DON/3ADON. In contrast to stem base colonization, in vitro inoculations of roots with a Tri5 deletion mutant deficient in Fg trichothecene production led to three-times higher colonization than the wildtype. Furthermore, an Fc isolate that produced low levels of zearalenone resulted in twice the level of colonization of a high DON/3ADON-producing isolate included in the study. When root inoculation with a low DON/3ADON-producing Fc isolate was supplemented with exogenous DON, DON production decreased by more than half per unit weight of Fc DNA, and root colonization doubled compared to the untreated control. Therefore, in contrast to its potential role as an aggressiveness factor in stem base infection, trichothecene production by Fc and Fg is detrimental to the early stages of wheat root colonization in FCR. 相似文献
12.
Masahiro Shishido Nanako Yoshida Toshiyuki Usami Tetsuo Shinozaki Masanobu Kobayashi Taeko Takeuchi 《Journal of General Plant Pathology》2006,72(4):220-227
Although the causal agent of black root rot of Cucurbitaceae in Japan has been proposed as Phomopsis sclerotioides, the species identification of the pathogen has remained inconclusive because of a lack of spore formation. We confirmed
that a Japanese isolate of Phomopsis sp. obtained from a diseased pumpkin root produced pycnidia containing α spores in sterilized bean pods. In phylogenetic
analyses of rDNA-ITS regions, nine Japanese Phomopsis sp. isolates from melon, watermelon grafted onto bottle gourd, and pumpkin diagnosed with black root rot, formed a single
clade with P. sclerotioides standard isolates. We identified the causal agent of the black root rot of melon, pumpkin, bottle gourd, and watermelon in
Japan as P. sclerotioides and propose the Japanese name “Phomopsis-negusare-byo” for the disease. Patterns of random amplified polymorphic DNA (RAPD) of these Japanese isolates were also similar
to those of P. sclerotioides, thus supporting the species identification. However, mycelial incompatibilities were found for many combinations among these
P. sclerotioides isolates, suggesting some genotypic variations of this fungus in Japan at a level that the RAPD analyses cannot discriminate.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB201430
to AB201444 相似文献
13.
Severe stunting and root rot were observed on alpine delphinium plants (Delphinium elatum) from Aomori Prefecture, Japan, in 2010 and 2011. A Phytophthora isolate from the diseased crown was identified as Phytophthora sp. kelmania based on morphological characteristics and DNA sequence data. Inoculation of alpine delphinium plants with the isolate produced a similar root rot. Pathogenicity of the isolate on four species of plants that are known hosts for P. sp. kelmania was confirmed. We propose the name “Phytophthora rot” (eki-byo in Japanese) for the present new disease on alpine delphinium.
相似文献14.
The purpose of this research was to identify the pathogens causing root and crown rot in major pomegranate-growing areas of Iran. Infected tissue samples were collected from trees with symptoms from 49 pomegranate orchards in four provinces of Iran: Fars, Markazi, Isfahan, and Kohgiluyeh va Boyer-Ahmad. In total, 23 Phytophthora spp. isolates were obtained, which were identified as P. cryptogea species complex (12 isolates) and P. cinnamomi (11 isolates) based on morphological characters. Molecular confirmation of identification was performed by inference of phylogeny of ITS-rDNA regions, β-tubulin gene, and the mitochondrial gene cytochrome c oxidase subunit 1. The results of our phylogenetic analysis confirmed the morphological identification of P. cinnamomi isolates and placed them in Clade 7c of Phytophthora. In addition, the P. cryptogea species complex isolates, despite morphological similarities, were in fact four distinct species including P. cryptogea sensu stricto (two isolates), P. pseudocryptogea (one isolate), P. sp. kelmania (one isolate), and P. erythroseptica (six isolates). This is the first report of pomegranate root and crown rot caused by P. cinnamomi and P. cryptogea species complex. 相似文献
15.
Characterization of Colletotrichum truncatum from papaya,pepper and physic nut based on phylogeny,morphology and pathogenicity
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C. Torres‐Calzada R. Tapia‐Tussell I. Higuera‐Ciapara E. Huchin‐Poot R. Martin‐Mex A. Nexticapan‐Garcez D. Perez‐Brito 《Plant pathology》2018,67(4):821-830
Colletotrichum truncatum (syn. C. capsici) has been identified as the causal agent of anthracnose on various hosts, predominantly pepper (Capsicum spp.) plants. The aim of this study was to determine whether C. truncatum isolates infecting papaya, pepper and physic nut in southeastern Mexico are morphologically, genetically and pathogenically different, in order to improve disease management strategies. A total of 113 C. truncatum isolates collected from five producer states were subjected to phenotypic characterization and divided into six different morphological groups. These morphological traits and the location of the isolates were used to select a subset of 20 isolates for further studies. Differences in the pathogenicity of the isolates were tested with a cross‐inoculation assay using pepper, papaya and physic nut. The pathogenicity tests revealed that all isolates could infect the three hosts and produce typical anthracnose symptoms, indicating a lack of host specificity for this species and therefore its pathogenic potential on other plants. Phylogenetic analysis using internal transcribed spacer (ITS) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) sequences of the C. truncatum isolates from this study and reference strains was performed, grouping the isolates into a monophyletic clade. This study reports for the first time the characterization of C. truncatum causing anthracnose disease on three different hosts in Mexico. 相似文献
16.
玉米内生菌L10的分离、鉴定及拮抗活性 总被引:2,自引:1,他引:2
为获得对玉米茎腐病主要病原菌禾谷镰孢Fusarium graminearum有明显拮抗作用的玉米内生菌,采用平板对峙法从成熟健康玉米茎秆中筛选禾谷镰孢拮抗菌株,并分析其抗菌谱;通过形态特征、生理生化特性及16S rDNA序列分析进行菌种鉴定;利用盆栽生防试验检测其对玉米茎腐病的防治效果。结果表明,共分离获得了164株玉米内生细菌菌株,其中L10菌株对禾谷镰孢具有较好的抑制效果,抑菌圈半径达1.68 cm;该菌对玉米大斑病菌Setosphaeria turcica、层出镰孢F. proliferatum、禾谷镰孢F. graminearum、拟轮枝镰孢F. verticilliodes、玉米弯孢叶斑病菌Curvularia lunata、玉米小斑病菌Bipolaris maydis、立枯丝核菌Rhizoctonia solani、茄链格孢Alternaria solani共8种植物病原菌均有拮抗作用,尤其对禾谷镰孢抑制效果最佳;结合形态特征、生理生化性质及16S rDNA序列分析,将L10菌株鉴定为多粘类芽胞杆菌Paenibacillus polymyxa。L10菌株脂肽类物质对禾谷镰孢菌具有较好的抑制活性,且盆栽生防试验结果显示该菌株对玉米茎腐病具有一定的防治效果。表明菌株L10对玉米镰孢茎腐病的防治具有一定潜力。 相似文献
17.
Claudia Torres-Calzada Raul Tapia-Tussell Inocencio Higuera-Ciapara Daisy Perez-Brito 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(1):67-79
Recently, anthracnose has become a major problem in papaya production and postharvest stages. The occurrence of both Colletotrichum gloeosporioides and Colletotrichum capsici has been demonstrated in this crop. The differential response of these pathogens to fungicides has highlighted the need to use rapid and accurate techniques to identify them. Thus, the objective of this study was to reveal the genetic diversity of Colletotrichum isolates in Mexican papaya fields. C. gloeosporioides-and C. capsici-specific primers were successfully used to detect the pathogens from different papaya parts. A combination of morphological characters, molecular techniques and pathogenicity tests were used to characterize 37 isolates from different localities of five papaya-producing states. Analyses of the 5.8-ITS region and arbitrarily primed-PCR revealed intraspecific groups; most of the isolates within these groups have the same geographical location and morphological characteristics. Knowledge of the genetic diversity of Colletotrichum spp. in Mexican papaya fields will facilitate the identification of the pathogen population in this crop in order to select the appropriate fungicide to control anthracnose, as well as to improve genetic resistance breeding programs. 相似文献
18.
Selection and Screening of Endorhizosphere Bacteria from Solarized Soils as Biocontrol Agents Against Verticillium dahliae of Solanaceous Hosts 总被引:4,自引:0,他引:4
Eleftherios C. Tjamos Dimitrios I. Tsitsigiannis Sotirios E. Tjamos Polymnia P. Antoniou Panayiotis Katinakis 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(1):35-44
Verticillium dahliae antagonistic endorhizosphere bacteria were selected from root tips of tomato plants grown in solarized soils. Fifty-three out of the 435 selected bacterial isolates were found to be antagonistic against V. dahliae and several other soilborne pathogens in dual cultures. Significant biocontrol activity against V. dahliae in glasshouse trials was demonstrated in three of 18 evaluated antagonistic isolates, provisionally identified as Bacillus sp. Although fluorescent pseudomonads were also isolated from root tips of tomato plants, none of the tested isolates exercised any significant antagonistic activity against V. dahliae in dual cultures. So these isolates were not tested in glasshouse trials in this study. Finally, two of the most effective bacterial isolates, designated as K-165 and 5-127, were shown to be rhizosphere colonizers, very efficient in inhibiting mycelial growth of V. dahliae in dual cultures and successfully controlling Verticillium wilt of solanaceous hosts. In glasshouse experiments, root dipping or soil drenching of eggplants with bacterial suspension of 107cfu ml–1 resulted in reduced disease severity expressed as percentage of diseased leaves (40–70%) compared to the untreated controls under high V. dahliae inoculum level (40 microsclerotia g–1 soil). In heavily Verticillium infested potato fields, experiments with potato seeds dusted with a bacterial talc formulation (108cfu g–1 formulation), showed a significant reduction in symptom development expressed as percentage of diseased potato plants and a 25% increase in yield over the untreated controls. As for their effectiveness in increasing plant height, both bacterial isolates K-165 and 5-127 produced indolebutyric, indolepyruvic and indole propionic acids. Both antagonists are considered as plant growth promoting rhizobacteria bacteria since significantly increased the height of treated plants compared with the untreated controls. Chitinolytic activity test showed that both isolates were able to produce chitinase. Testing rhizospheric and endophytic activity of the antagonists it was shown that although the bacteria are rhizosphere inhabitants they also preferentially colonize the endorhizosphere of tomatoes and eggplants. Fatty acid analysis showed that isolate K-165 could belong to Paenibacillus alvei while 5-127 to Bacillus amiloliquefaciens. 相似文献
19.
Leah L. Granke Lina M. Quesada-Ocampo Mary K. Hausbeck 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(2):281-296
Phytophthora capsici causes root, crown, and fruit rot of vegetable and tropical hosts. Cucumber, zucchini, tomato, and pepper fruits were inoculated
using 6-mm-diameter agar plugs of P. capsici, incubated in clear plastic boxes at room temperature (25 ± 2°C and 100% relative humidity), and virulence was estimated
by measuring the lesion diameter, pathogen growth diameter, and pathogen sporulation density three (cucumber, zucchini) or
four (tomato, pepper) days later. When isolates were grouped by genetic cluster, significant differences in virulence were
observed on cucumber and zucchini, with isolates belonging to genetic cluster five causing larger lesions than isolates from
genetic cluster six. On tomato, no significant differences were observed for isolates grouped by genetic cluster, but isolates
from vegetable crops were generally more virulent than isolates from tropical hosts. Isolates from fabaceous hosts sporulated
better on cucumber fruits than isolates from solanaceous hosts. Isolates from vegetable hosts sporulated better on zucchini
than isolates from tropical hosts. No significant differences in lesion diameter were noted on pepper when isolates were grouped
by host family of origin or genetic cluster, but differences in pathogen sporulation were apparent by host family. Our findings
suggest that isolate characteristics such as host family of origin and genetic cluster membership may be used to guide initial
isolate selection for cucurbit fruit resistance screening. Final isolate selection should incorporate the phenotypic and genetic
diversity of P. capsici, including isolates with differing virulence to the host organ of interest. 相似文献
20.
Sang-Woo Lee Il-Pyung Ahn Sang-Yeon Sim Sue-Yeon Lee Myeon-Whoon Seo Soonok Kim Sook-Young Park Yong-Hwan Lee Seogchan Kang 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(1):1-11
A Gram-negative rhizobacterial isolate (LSW25) antagonistic to Pseudomonas corrugata, a vein necrosis pathogen of tomato, and promotes the growth of tomato seedlings was isolated from surface-sterilised tomato roots. A spontaneous rifampicin-resistant
mutant (LSW25R) was selected to facilitate its tracking, and identified as Pseudomonas sp. and named as Pseudomonas sp. LSW25R (LSW25R), based on its sequences of the internal transcribed spacer (ITS) region and 16 S rRNA gene. LSW25R inhibited
mycelial growth of 12 other plant fungal pathogens such as Botrytis cinerea on V8 agar plates. By using a scanning electron microscope, LSW25R colonised not only the root surface around the natural
aperture of tomato radicles but also under epidermal cells like endophytic bacteria. LSW25R successfully colonised the roots
of tomato, eggplant and pepper seedlings, significantly promoted the fresh weight, height and dry matter of tomato plants
at 108 cfu·ml−1, and increased the plant growth of eggplants and peppers at 104 cfu·ml−1, suggesting that the optimal population density of LSW25R for growth promotion varies from species to species. Moreover,
densities of LSW25R inside roots and the lowest leaf of tomato plants were > 9.3 × 103 cfu·g−1. Although the growth promotion of tomato by LSW25R was observed under N- or Ca-deficient conditions as well as a standard
nutrient condition, the uptake of calcium was increased only under the standard nutrient condition. In a hydroponic system,
LSW25R not only successfully colonised the rhizosphere during cultivation due to its broad spectrum of antifungal activity
and endophytic colonisation, but also reduced blossom-end rot of tomato fruits presumably through increasing calcium uptake. 相似文献