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1.
Alessandro Pirondi Agostino Brunelli Enrico Muzzi Marina Collina 《Journal of General Plant Pathology》2017,83(4):244-252
Late blight caused by Phytophthora infestans is the most devastating disease of tomato (Solanum lycopersicum L.) and causes important economically losses if not properly controlled. Control is achieved mainly by preventive fungicide applications. However, even if curative applications are discouraged because they increase the risk of resistance development in the target pathogens, in practice fungicides may be applied also when the disease is already present, a situation that commonly occurs in the field. The aim of this work was to study the curative activity of several fungicides toward P. infestans to determine their efficacy when applied after the infection process. Nine trials were performed in greenhouse using potted tomato plants that were treated 24 h after inoculation. Disease severity was assessed three times from the development of the symptoms on the untreated plants and data analysed using a linear mixed model. Differences in post-infection control between the different chemical classes were found. Metalaxyl-M and cymoxanil showed the best curative activity while among the CAA fungicides, a good efficacy was expressed by dimethomorph. Interestingly, evidence of synergy between active ingredients having different modes of action was observed such as in the mixtures containing dimethomorph?+?ametoctradin, dimethomorph?+?pyraclostrobin and fosetyl-Al?+?propamocarb. This study provided useful information on the post-infection activity of some fungicides used to control tomato late blight and should be taken into account to perform more in depth studies at the field level and to improve the management strategies of the disease. 相似文献
2.
Sana Tabanda Saeed B. Kumar A. K. Shasany A. Samad 《Journal of General Plant Pathology》2017,83(5):333-336
Whitefly-transmitted begomovirus induces leaf curling and stunting of Mentha arvensis (Kosi) and is responsible for heavy economic losses in and around Lucknow, India. The complete genome was amplified, sequenced and assembled as 2759 bp long, with 1376 bp betasatellite molecule. Because no DNA-B amplicon was detected, the virus was classified as “Old World begomovirus” with the characteristic seven ORFs; two ORFs (AV1, AV2) in the V-sense and five ORFs (AC1–AC5) in the C-sense. BLASTn and phylogenetic analysis showed highest similarity (98%) with chilli leaf curl India virus (ChiLCINV). This is the first report of ChiLCINV infection in M. arvensis (Kosi) from India. 相似文献
3.
Sidra Anwar 《Journal of General Plant Pathology》2017,83(3):185-188
Leaf samples of Cucurbita pepo with yellow mosaic disease symptoms were collected in 2012. Rolling circle amplification and PCR amplification with begomovirus-specific primers confirmed the presence of an Old World bipartite begomovirus, an alphasatellite and a betasatellite. Molecular analysis of full-length sequences showed that Tomato leaf curl New Delhi virus (DNA-A) is associated with its cognate DNA-B, Papaya leaf curl betasatellite and a novel alphasatellite. To the best of our knowledge, this is the first report of an alphasatellite and a betasatellite associated with a bipartite begomovirus. 相似文献
4.
Tsunaki Andou Ayako Yamaguchi Shinji Kawano Kunimasa Kawabe Shigenori Ueda Masatoshi Onuki 《Journal of General Plant Pathology》2010,76(4):287-291
In 2005, severe leaf curling and yellowing were observed on tomato plants on Ishigaki Island. Because the symptoms were consistent
with infection by a begomovirus, we used a polymerase chain reaction (PCR) with specific primers for begomovirus DNA-A and
DNA satellite component (DNA-β) and detected products of the expected sizes from symptomatic tomato plant samples. DNA sequence
analyses of the PCR products revealed that the symptomatic tomato plants were associated with Ageratum yellow vein virus (AYVV) infection. We confirmed AYVV transmission from the naturally infected weed host, Ageratum conyzoides, to healthy tomato plants by the insect vector Bemisia tabaci B biotype. This report is the first of AYVV occurrence in Japan. 相似文献
5.
In October 2009, vein yellowing disease was observed on the weeds Crassocephalum crepidioides and Ageratum conyzoides in a subtemperate region in northern India. Ageratum enation virus (AEV), along with a nanovirus like satellite DNA 1, was found to be associated with both weeds. The isolates had 99% identity
with each other and with an isolate of AEV reported from Zinnia elegans from this region. To the best of our knowledge, this report is the first of any begomovirus infection in C. crepidioides in India and the first on AEV infecting C. crepidioides worldwide and A. conyzoides in India. 相似文献
6.
Mona Rabie Claudio Ratti Matteo Calassanzio Engy Abdel Aleem Faiza Aref Fattouh 《European journal of plant pathology / European Foundation for Plant Pathology》2017,149(1):219-225
Four Cucumber mosaic virus (CMV) (CMV-HM 1–4) and nine Tomato mosaic virus (ToMV) (ToMV AH 1–9) isolates detected in tomato samples collected from different governorates in Egypt during 2014, were here characterized. According to the coat protein gene sequence and to the complete nucleotide sequence of total genomic RNA1, RNA2 and RNA3 of CMV-HM3 the new Egyptian isolates are related to members of the CMV subgroup IB. The nine ToMV Egyptian isolates were characterized by sequence analysis of the coat protein and the movement protein genes. All isolates were grouped within the same branch and showed high relatedness to all considered isolates (98–99%). Complete nucleotide sequence of total genomic RNA of ToMV AH4 isolate was obtained and its comparison showed a closer degree of relatedness to isolate 99–1 from the USA (99%). To our knowledge, this is the first report of CMV isolates from subgroup IB in Egypt and the first full length sequencing of an ToMV Egyptian isolate. 相似文献
7.
Francisco Alejo-Iturvide Maria Azucena Márquez-Lucio Isaías Morales-Ramírez Ma. Soledad Vázquez-Garcidueñas Víctor Olalde-Portugal 《European journal of plant pathology / European Foundation for Plant Pathology》2008,120(1):13-20
Hydrogen peroxide (H2O2) has been implicated in many stress conditions. Control of H2O2 levels is complex and dissection of mechanisms generating and relieving H2O2 stress is difficult, particularly in intact plants. Here the role of the mycorrhizal inoculation in chili plants challenged
with Phytophthora capsici was investigated to study the effect on hypersensitive response. In the treatment without mycorrhiza (treatment T3) and with
mycorrhiza (considered treatment T4) visible disorders were detected two days after inoculation with P. capsici, but in the next days T3 plants rapidly developed 25% more necrotic lesions on the leaves than T4 plants. Leaf necrosis correlated
with H2O2 accumulation and the greater damage observed in T3 plants coincided with larger accumulation of H2O2 after 12 h of inoculation accompanied with an increase in POX (peroxidase) and SOD (superoxide dismutase) activity. T4-infected
and mycorrhizal plants exhibited an earlier accumulation of H2O2 starting 6 h after inoculation with lower levels compared to T3 plants. Correlated with observed damage, POX and SOD activity
measured in T4 plants indirectly suggest a smaller accumulation of ROS (reactive oxygen species) leading to a decrease in
the wounds observed and slightly diminishing the advance of the pathogen. According to these findings, we conclude that mycorrhizal
colonization contributes significantly in maintaining the redox balance during oxidative stress, but the exact mechanism is
still uncertain. 相似文献
8.
In May 1998 and 1999, two types of leaf spot (black type and brown type) caused by Phoma spp. were found on Farfugium japonicum in Tokyo and in Gunma Prefecture, Japan. The fungus isolated from black-type lesions caused only black-type lesions, and the fungus from brown-type lesions caused only brown-type lesions. We propose to name these diseases black leaf spot of F. japonicum (kokuhan-byo in Japanese) for the disease with black lesions and circular leaf spot of F. japonicum (rinmon-byo in Japanese) for the disease with brown lesions. This is the first report on leaf diseases of F. japonicum caused by Phoma spp. 相似文献
9.
Aviv Dombrovsky Eyal Glanz Mali Pearlsman Oded Lachman Yehezkel Antignus 《Phytoparasitica》2010,38(5):477-486
Pepper (Capsicum annuum) is an important crop worldwide. In Israel, approximately 2,500 ha are grown all year round for the local and export markets.
Herein, we report the identification of a viral pathogen causing a new devastating disease in pepper crops. The disease syndrome
includes shortening of stem internodes, interveinal yellowing, and upward rolling of the leaf blade, accompanied by fruit
discoloration and size reduction. Virus purification from infected plants yielded isometric particles, 25 nm in diameter.
The causal agent of the disease was tentatively named Pepper yellow leaf curl virus (PYLCV). The virus cross-reacted in DAS ELISA with antisera against Cucurbit aphid-borne yellows virus and Potato leafroll virus, members of the Polerovirus genus. The partial nucleotide sequence obtained from the cloned viral coat protein and movement protein genes indicated 92%
identity at the amino acid level with Tobacco vein distortion virus (TVDV), another member of the Polerovirus genus. However, the host range of PYLCV is significantly different from the host range described for TVDV. Based on our findings,
the taxonomic status of PYLCV is discussed. 相似文献
10.
Masamichi Isogai Koji Ishii Seisaku Umemoto Manabu Watanabe Nobuyuki Yoshikawa 《Journal of General Plant Pathology》2009,75(2):140-143
Virus-like symptoms—red ringspots on stems and leaves, circular blotches or pale spots on fruit—were found on commercial highbush
blueberry (Vaccinium
corymbosum) cultivars Blueray, Weymouth, Duke and Sierra in Japan. In PCR testing, single DNA fragments were amplified from total nucleic
acid samples of the diseased blueberry bushes using primers specific to Blueberry red ringspot virus (BRRV). Sequencing analysis of the amplified products revealed 95.7–97.7% nucleotide sequence identity with the BRRV genome.
This paper is the first report of blueberry red ringspot disease caused by BRRV in Japan.
The nucleotide sequence data reported in this paper are available in the GenBank/EMBL/DDBJ database as accessions AB469884
to AB469893 for BRRV isolates from Japan. 相似文献
11.
Shima Bagherabadi Doustmorad Zafari Yousef Moradi Amirabad Joyce H. C. Woudenberg 《Journal of General Plant Pathology》2017,83(6):398-401
Drimia maritima (squill) is a historically important medicinal plant. During the spring of 2016, small, yellow leaf spots, which became brown and finally necrotic, were observed on squill plants in Kohgiluyeh and Boyer-Ahmad Provinces in Iran. A fungus was consistently isolated from infected leaves and identified as Alternaria alternata based on morphological and phylogenetic analyses. Pathogenicity tests confirmed A. alternata to be the causal agent of the newly observed leaf spot disease. This is the first report of leaf spot on D. maritima caused by A. alternata in the world. 相似文献
12.
R. Lebecka 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(2):345-348
Solanum nigrum, black nightshade, is a wild non-tuber bearing hexaploid species with a high level of resistance to Phytophthora infestans (Colon et al. 1993), the causal agent of potato late blight, the most devastating disease in potato production. However, the genetic mode of
resistance in S. nigrum is still poorly understood. In the present study, two S. nigrum accessions, 984750019 (N19) and #13, resistant (R) and susceptible (S), respectively, to three different isolates of P. infestans, were sexually crossed. The various kinds of progeny including F1, F2, F3, and backcross populations (BC1; F1 × S), as well as two populations produced by self-pollinating the R parent and S parent, were each screened for susceptibility
to P. infestans isolate MP 324 using detached leaf assays. Fifty seedling plant individuals of the F1 progeny were each resistant to this
specific isolate, similarly to the seedling plants resulting from self-pollination of the resistant R parent. Thirty seedling
plants obtained from self-pollination of the S parent were susceptible. Among a total of 180 F2 plants, the segregation ratio
between resistant and susceptible plants was approximately 3: 1. Among the 66 seedling plants of the BC1 progeny originating from crossing an F1 plant with the susceptible S parent, there were 26 susceptible and 40 resistant plants
to P. infestans. The segregation patterns obtained indicated monogenic dominant inheritance of resistance to P. infestans isolate MP 324 in S. nigrum acc. 984750019. This gene, conferring resistance to P. infestans, may be useful for the transformation of potato cultivars susceptible to late blight. 相似文献
13.
Luigi Faino Paola Carli Antonino Testa Gennaro Cristinzio Luigi Frusciante Maria Raffaella Ercolano 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(2):233-241
Tomato is challenged by several pathogens which cause loss of production. One such pathogen is the oomycete Phytophthora infestans which is able to attack all the aerial parts of the plant. Although a wide range of resistance sources are available, genetic
control of this disease is not yet successful. Pyramiding R-genes through genetic transformation could be a straightforward
way to produce tomato and potato lines carrying durable resistance to P. infestans. In this work the R1 potato gene was transferred into tomato lines. The tomato transgenic lines were analyzed by using q-RT-PCR
and progeny segregation to determine the gene copy number. To test the hypothesis that R1 represents a specifically regulated R-gene, transgenic tomato plants were inoculated with P. infestans isolate 88133 and IPO. All the plants containing the R1 gene were resistant to the late blight isolate IPO-0 and susceptible to isolate 88133. These results provide evidence for
specific activation of the R1 gene during pathogen challenge. Furthermore, evidence for enhancement of PR-1 gene expression during P. infestans resistance response was obtained. 相似文献
14.
Weed control is a major concern for organic farmers around the world and non-chemical weed control methods are now the subject
of many investigations. Field studies were conducted in tomato (Solanum lycopersicum L.) from 2004 to 2006 at the Black Sea Agricultural Research Institute experiment field to determine the weed suppressive
effects of winter cover crops. Treatments consisted of ryegrass (Lolium multiflorum L.), oat (Avena sativa L.), rye (Secale cereale L.), wheat (Triticum aestivum L.), gelemen clover (Trifolium meneghinianum Clem.), Egyptian clover (Trifolium alexandrinum L.), common vetch (Vicia sativa L.), hairy vetch (Vicia villosa Roth.) and a control with no cover crop. Treatments were arranged in a randomized complete block design with four replications.
To determine the weed suppressive effects of the cover crops, weed density and total weed dry biomass were assessed at 14,
28, and 56 days after termination (DAT) of the cover crops from all plots using a 50 × 50 cm quadrat placed randomly in each
plot. After cover crop kill and incorporation into soil, tomato seedlings variety ‘H2274’ were transplanted. Broadleaved weed
species were the most prominent species in both years. Total weed biomass measured just prior to cover crop incorporation
into the soil was significantly lower in S. cereale plots than in the others. The number of weed species was lowest at 14 DAT and later increased at 28 and 56 DAT, and subsequently
remained constant during harvest. This research indicates that cover crops such as L. multiflorum, S. cereale, V. sativa and V. villosa could be used in integrated weed management programs to manage some weeds in the early growth stages of organic tomato. 相似文献
15.
Ahmed A. Kheder Yasunori Akagi Hajime Akamatsu Konomi Yanaga Nitaro Maekawa Hiroshi Otani Takashi Tsuge Motoichiro Kodama 《Journal of General Plant Pathology》2012,78(1):30-38
The tomato pathotype of Alternaria alternata (A. arborescens) produces the dark brown to black pigment melanin, which accumulates in the cell walls of hyphae and conidia. Melanin has
been implicated as a pathogenicity factor in some phytopathogenic fungi. Here, two genes of the tomato pathotype for melanin
biosynthesis, ALM1 and BRM2-1, which encode a polyketide synthetase and a 1,3,8-trihydroxynaphthalene (THN) reductase, respectively, have been cloned and
disrupted in the pathogen. The gene-disrupted mutants, alm1 and brm2-1, had albino and brown phenotypes, respectively. The wild-type and the mutants caused the same necrotic lesions on the leaves
after inoculation with spores. These results suggest that melanin is unlikely to play a direct role in pathogenicity in the
tomato pathotype A. alternata. Scanning electron microscopy revealed that the conidia of both mutants have much smoother surfaces in comparison to the
wild-type. The conidia of those mutants were more sensitive to UV light than those of the wild-type, demonstrating that melanin
confers UV tolerance. 相似文献
16.
Rudra P. Singh Andrea D. Dilworth Xiaoping Ao Mathuresh Singh Virendra K. Baranwal 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(4):691-694
Surveys of Impatiens and Verbena species in local nurseries in Fredericton, Canada and Verbena species in New Delhi, India showed widespread infection of Citrus exocortis viroid (CEVd) in vegetatively-propagated and seed-grown plants. To determine viroid seed transmission, samples of eight varieties
of Impatiens and 11 varieties of Verbena were obtained from four commercial sources. All 19 samples collected contained viroid infection irrespective of variety.
The presence of viroid in non-germinated seed was 21%, while the transmission rate in seedlings was 66% in Impatiens walleriana in 2006. Following 2 years of seed storage, the respective figures were 6% and 26%. Similarly, in Verbena x hybrida the presence of viroid in seed was 13% in 2006 with a seed-transmission rate in seedlings of 28%, while the respective figures
after 2 years of storage were 5% and 45%. 相似文献
17.
Maria Lodovica Gullino Giovanna Gilardi Mattia Sanna Angelo Garibaldi 《Phytoparasitica》2009,37(5):461-466
Leaf spot of tomato, incited by Pseudomonas syringae pv. syringae, has been reported recently in Italy on grafted and non-grafted tomato plants (scion Cuore di Bue, rootstock Solanum lycopersicum x Solanum hirsutum cv. Beaufort). In some greenhouses, more than 80% of plants were affected, with a marked reduction in yield. This work was
undertaken in order to understand the effect of the number of hours of incubation at high relative humidity (r.h.) and temperature
as well as the effect of the presence of wounds at infection time on the development of leaf spot. A difference in sensitivity
to leaf spot was observed in the various cultivars tested, in terms of severity of P. syringae pv. syringae, with “Cuore di Bue” being the most susceptible of these cultivars. The development of leaf spot is mostly favored by the
presence of wounds, at temperatures between 15 and 20°C. The severity of the disease is lower at 10 and 25°C and very low
at 30°C. Under the most favorable temperature conditions, the presence of wounds is sufficient to allow the development of
the pathogen immediately upon incubation at high r.h. The effect of wounds and the relatively low requirement of hours of
incubation at high r.h. suggest the need for careful management and handling of plants when temperatures range between 15
and 25°C, and particularly within 15 and 20°C. All operations carried out, particularly at transplant and immediately after,
should avoid the creation of wounds. 相似文献
18.
Hüseyin Basım Esin Basım Derya Baki Muntala Abdulai Nurhan Öztürk Recep Balkic 《European journal of plant pathology / European Foundation for Plant Pathology》2018,150(1):73-90
A new dagger nematode, Xiphinema tica n. sp., is described and illustrated from several populations extracted from soil associated with several crops and wild plants in Costa Rica. The new dagger nematode is characterised by a moderate body size (3276–4240 μm), a rounded lip region, ca 13.5 μm wide, separated from body contour by a shallow depression, amphidial fovea large, stirrup-shaped, a moderately long odontostyle ca 135 μm long, stylet guiding ring located at ca 122 μm from anterior end, vulva almost equatorial (50–54%), well-developed Z-organ, with heavy muscularised wall containing in the most of specimens observed two moderately refractive inclusions variable in shape (from round to star-shaped), with uterine spines and crystalloid bodies; female tail short, dorsally convex-conoid, with rounded end and a small peg, with a c’ ratio ca 0.8, bearing two or three pairs of caudal pores and male absent. The unique and novel uterine differentiation based on the coexistence of a well-developed Z-organ mixed with uterine spines and crystalloid bodies in Xiphinema prompted us to update and include this combination of characters in the polytomous key of Loof and Luc (1990). Integrative diagnosis was completed with molecular data obtained, using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA, partial 18S–rDNA and the partial mitochondrial gene cytochrome c oxidase subunit 1 (coxI). The phylogenetic relationships of this species with other Xiphinema spp. indicated that X. tica n. sp. was monophyletic to the other species from the morphospecies Group 4, Xiphinema oleae. 相似文献
19.
Fusarium head blight in small grain cereals has emerged as a major problem in the Nordic countries. However, the impact of
this disease in oats has been less investigated than in other cereals. For this reason we have studied the infection process
(the optimal time of infection and infection pathways) of Fusarium graminearum in oats and its subsequent effects on kernel infection, deoxynivalenol (DON) content and germination capacity. In a field
experiment the oat cultivar Morton was spray-inoculated at different developmental stages, and the highest kernel infection
and DON content and lowest germination percentage were observed when inoculation took place at anthesis. Field grown oats
affected by a natural Fusarium head blight epidemic and spray-inoculated field and greenhouse oats were used to study the
infection pathway. Results showed that the fungus entered primarily through the floret apex into the floret cavity, where
it could infect via the internal surfaces of the palea, lemma and caryopsis. Both visual symptoms and fungal infections started at the apical
portions of the florets and progressed to the basal portions. Hyphae of F. graminearum grew more profusely on the anthers than on other floret parts during initial stages of infection. Disease development within
the oat panicle was slow and is primarily by physical contact between adjoining florets, indicating that the long pedicels
give Type II resistance in oats. 相似文献
20.
Shohei Matsuura Yosuke Matsushita Reiko Kozuka Sachiko Shimizu Shinya Tsuda 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(1):111-115
Quantitative PCR revealed that Tomato chlorotic dwarf viroid (TCDVd) was present in substantial amounts in viroid-infected tomato flowers. Healthy tomato plants were arranged in two
different glasshouses, and plants were mechanically inoculated with TCDVd. Bumblebees (Bombus ignitus) were then introduced into the glasshouses to reveal whether the viroid was transmitted from infected source plants to neighbouring
healthy plants. TCDVd infection was found in neighbouring tomato plants more than 1 month after the introduction of the bees,
some of which expressed symptoms, in both glasshouses. Thus, bumblebees transmitted TCDVd from tomato to tomato by pollination
activities. 相似文献