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981.
Abu Shamim Mohammad Nahiyan Louisa Robinson Boyer Peter Jeffries Yoh-ichi Matsubara 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(2):197-203
The diversity of Fusarium populations in asparagus (Asparagus officinalis L.) decline fields in Japan was estimated by PCR-SSCP (single-stranded conformational polymorphism) analysis of the ITS2
regions of the nuclear rRNA genes. This method was used to rapidly and objectively identify pathogens associated with roots
of plants showing symptoms of asparagus decline collected from fields in five regions across Japan. Over 651 fusarial isolates
were obtained, and were easily differentiated into three principal species. Fusarium oxysporum f. sp. asparagi was most frequently isolated from the domestic five regions (68%), whereas Fusarium proliferatum (28.6%) was less frequent. Fusarium solani was found much rarely (2.5%). The frequency of isolation of Fusarium proliferatum increased gradually from the north to the south of Japan, though considerable differences were found between fields in each
region, as well as regional differences among the Fusarium populations. Most of the fusarial isolates were highly pathogenic in vitro. These results reveal that Fusarium oxysporum f. sp. asparagi and Fusarium proliferatum are important biotic factors which lead to asparagus decline in Japan. 相似文献
982.
Warrick R. Nelson Tonja W. Fisher Joseph E. Munyaneza 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):5-12
Three haplotypes of the recently discovered bacterium species “Candidatus Liberibacter solanacearum” are described and related to geographic ranges. The first two are associated with Zebra Chip/Psyllid
Yellows of potatoes and other solanaceous plants, vectored by the tomato/potato psyllid Bactericera cockerelli in North and Central America and New Zealand. The third is associated with diseased carrots in Finland and vectored by the
carrot psyllid Trioza apicalis. The haplotypes are described by SNPs on the 16s rRNA, 16s/23s ISR and 50s rplJ and rplL ribosomal protein genes. These SNPs
are inherited as a package across the three genes. Haplotype “a” has been found primarily from Honduras and Guatemala through
western Mexico to Arizona and California, and in New Zealand. Haplotype “b” is currently known from eastern Mexico and northwards
through Texas to south central Washington. These haplotypes show some range overlap in Texas, Kansas and Nebraska. The haplotypes
are not yet known to elicit biological differences in the plant or insect hosts. These apparently stable haplotypes suggest
separate bacterial populations of long standing. 相似文献
983.
Odile Carisse Catherine Meloche William W. Turechek 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(3):349-365
The spatial pattern of apple scab was characterized using 10 years of disease incidence and lesion density data collected
in managed orchards located in Quebec, Canada. Distributional analyses indicated that scab incidence was better characterized
by the beta-binomial than the binomial distribution in 53 and 65% of the data sets at the leaf and shoot scales, respectively.
Median values of the beta-binomial parameter θ, a measure of small-scale aggregation, were near 0 (0.003 and 0.028) at both
sampling scales, indicating that disease incidence was close to being randomly distributed (low degree of aggregation). For
lesion density, the negative binomial distribution fitted the data better than the Poisson distribution in 86% of the data
sets at the leaf scale. The median value of the index of dispersion k was 0.068, indicating that aggregation was present. For all apple scab measurements, the power law models provided a good
fit to the data. The estimated slope and intercept parameters were significantly greater than 1 and 0, respectively, suggesting
that spatial heterogeneity changed systematically with disease incidence. Results of a covariance analysis showed that spatial
heterogeneity of scab incidence at both scales and lesion density was not dependent upon shoot type but that spatial heterogeneity
of scab incidence and lesion density at the leaf scale was influenced by the sampling period. A hierarchical analysis showed
that scab incidence at the tree scale increased as a saturation-type curve with respect to incidence at the leaf or shoot
scales. A similar relationship was observed for incidences at the shoot and leaf scales. An effective sample size model based
on the binary power law parameters (Madden and Hughes, Phytopathology 89:770–781, 1999) gave the best fit to the leaf and shoot data, respectively. The incidence-lesion density relationship at both scales was
well described by a complementary log-log (CLL) and log transformation model ( Radj2 = 0.97 and Radj2 = 0.94 ) \left( {R_{{adj}}^2 = 0.97\,and\,R_{{adj}}^2 = 0.94} \right) , however, the models tended to underestimate lesion density. The information of the spatial relations of apple scab within
and between hierarchical scales acquired from this study can be used in developing and evaluating practical disease management
strategies and to improve apple scab assessments for fungicide or cultivar susceptibility trials. 相似文献
984.
Otmar Spring Thines Marco Stefanie Wolf Reinhard Zipper 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):519-527
Sequencing of partial cox2 (part of the mitochondrial cytochrome-c-oxydase (COX) gene) was performed with samples from the oomycete genus Pustula, the white blister rusts of Asteraceae and related families. Sequence comparison uncovered several single nucleotide polymorphisms
(SNPs) between P. spinulosa and host specific strains of Pustula isolated from Senecio vulgaris, Tragopogon pratensis and cultivated sunflower, Helianthus annuus. Based on these differences, specific primers were designed for PCR-based detection of white blister rust strains pathogenic
to sunflower. The specificity of the primers was confirmed by cross testing with DNA from various oomycetes occurring in the
same locality. The limit of detection for DNA of P. helianthicola was 10 pg. This allowed detection with DNA from single sporangia and single oospores. The PCR-based experiments allowed detection
of the presence of sunflower white blister rust in soil samples from fields on which infected plants had been cultivated several
months before. Moreover, the molecular tools were successfully applied to trace the pathogen in asymptomatic tissue of infected
plants, demonstrating the systemic nature of Pustula on sunflower. 相似文献
985.
Ferenc Viranyi Otmar Spring 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(2):207-220
This review summarises the progress in research on sunflower downy mildew as reported in publications of the past 10 to 15 years,
the period since the last comprehensive review on Plasmopara halstedii. Particular attention is paid to subjects that showed much progress and may be of particular interest to sunflower pathologists,
mycologists or molecular biologists. Accordingly, single sections are devoted to the problems of taxonomic and phylogenetic
aspects, host specificity, the host—pathogen interaction including resistance phenomena, as well as epidemiology and disease
management. Reflecting the progress achieved in some fields and illuminating the deficits in others should stimulate the reader's
interest in this very significant pathosystem. 相似文献
986.
Marie Gosme Philippe Lucas 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(1):119-131
The importance of the spatial aspect of epidemics has been recognized from the outset of plant disease epidemiology. The objective
of this study was to determine if the host spatial structure influenced the spatio-temporal development of take-all disease
of wheat, depending on the inoculum spatial structure. Three sowing patterns of wheat (broadcast sowing, line sowing and sowing
in hills) and three patterns of inoculum (uniform, aggregated and natural infestation) were tested in a field experiment,
repeated over 2 years. Disease (severity, root disease incidence, plant disease incidence and, when applicable, line and hill
incidences) was assessed seven times during the course of each season and the spatial pattern was characterized with incidence-incidence
relationships. In the naturally infested plots, disease levels at all measurement scales were significantly higher in plots
sown in hills, compared to plots sown in line, which were in turn significantly more diseased than plots with broadcast sowing.
Disease aggregation within roots and plants was stronger in line and hill sowing than in broadcast sowing. Analysis of the
disease gradient in the artificially infested plots showed that the disease intensified (local increase of disease level)
more than it extensified (spatial spread of the disease), the effect of the introduced inoculum was reduced by 95% at a distance
of 15 cm away from the point of infestation. Yield was not significantly affected by sowing pattern or artificial infestation. 相似文献
987.
Oliver A. H. Jones Mahon L. Maguire Julian L. Griffin Young-Ho Jung Junko Shibato Randeep Rakwal Ganesh K. Agrawal Nam-Soo Jwa 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(4):539-554
A metabolomics based approach has been used to study the infection of the Hwacheong rice cultivar (Oryza sativa L. cv. Hwacheong) with compatible (KJ201) and incompatible (KJ401) strains of the rice blast fungal pathogen Magnaporthe grisea. The metabolic response of the rice plants to each strain was assessed 0, 6, 12, 24, 36, and 48 h post inoculation. Nuclear
Magnetic Resonance (NMR) spectroscopy and Gas and Liquid Chromatography Tandem Mass spectrometry (GC/LC-MS/MS) were used to
study both aqueous and organic phase metabolites, collectively resulting in the identification of 93 compounds. Clear metabolic
profiles were observed at each time point but there were no significant differences in the metabolic response elicited by
each pathogen strain until 24 h post inoculation. The largest change was found to be in alanine, which was ~30% (±9%) higher
in the leaves from the compatible, compared to the resistant, plants. Together with several other metabolites (malate, glutamine,
proline, cinnamate and an unknown sugar) alanine exhibited a good correlation between time of fungal penetration into the
leaf and the divergence of metabolite profiles in each interaction. The results indicate both that a wide range of metabolites
can be identified in rice leaves and that metabolomics has potential for the study of biochemical changes in plant-pathogen
interactions. 相似文献
988.
Yosuke Matsushita Tomio Usugi Shinya Tsuda 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(4):441-447
In situ hybridization was used to analyze the distribution pattern of Tomato chlorotic dwarf viroid (TCDVd) in floral organs of tomato plants. Following TCDVd invasion of floral organs, it became localized only in sepals
at an early developmental stage, then reached other floral organs at the flower opening stage, with the exception of part
of the placenta and ovules. When distribution of TCDVd was compared with that of Potato spindle tuber viroid (PSTVd), TCDVd was not detected in the outer integument around the embryo sac even though PSTVd was able to invade there,
suggesting that such specific distribution might reflect the frequent occurrence of viroid disease on crops caused by PSTVd-seed
transmission. 相似文献
989.
Evaluation of perennial wild <Emphasis Type="Italic">Cicer</Emphasis> species for drought resistance
About 90% of chickpea (Cicer arietinum L.) in the world is grown under rainfed conditions where drought is one of the major constraints limiting its productivity.
Unlike the cultivated chickpea, wild Cicer species possesses sources of resistance to multiple stresses; we therefore evaluated perennial wild Cicer species for resistance to drought. C. anatolicum, C. microphyllum, C. montbretii, C. oxydon and C. songaricum were compared with special checks; C. echinospermum, C. pinnatifidum and C. reticulatum and five cultivated chickpeas. After the cultivated chickpeas were killed, accessions were evaluated using a 1–5 scale, where
1 = highly drought resistant (no visible drought effect and full recovery after three successive wiltings) and 5 = highly
drought susceptible (leaves and branches dried out, no recovery at all). All accessions of perennial wild Cicer species were significantly superior to those annual wild species and the cultivated chickpeas including the best drought
tolerant chickpea, ICC 4958 under drought conditions. Perennial wild Cicer species did not only recover after wilting and drying out above ground level, they also tolerated high temperatures up to
41.8°C. But, they do not cross with the cultivated chickpeas. C. anatolicum should be taken account in long term breeding programs because it has closer affinities to the first crossability group than
the others. 相似文献
990.
The study here was conducted on nearly 12,000 apricot seedlings in the Malatya Region in the Eastern part of Turkey. This
region is famous for its horticulture based mainly on apricot production and the Country's highest apricot production originates
from this region. The flower and fruit characteristics of all populations, which include apricot seedlings, in the region
were evaluated. Based on their horticultural performances, 13 genotypes were selected, of which seven were considered as apricots
served in dried form and six as in table consumption form. Among the selected genotypes, the fruit weight ranged between 28.5
and 71.19 g, soluble solids ranged between 12.7 and 26.5%, while the range in total acidity was between 0.35 and 1.80% and
fruit development period was between 87 and 183 days. To determine the selected genotypes performance in a similar environment,
they were grafted on to 4-year-old rootstocks. The results from these combinations showed that there was some decrease, especially
in fruit size and soluble solids, in the genotypes performance when compared to the results of the initial observations. Some
differences were also detected in taste, fruit shape, pit shape, fruit flesh firmness, skin and flesh colors. The dry fruit
yield was determined as 22.50–28.36% for the selected dry apricot genotypes. The dry fruit yield of all seven genotypes considered
for dry consumption were similar to ‘Hacıhaliloğlu’ and higher than ‘Canino’, which were evaluated as control cultivars. 相似文献