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991.
Here Fusarium oxysporum was killed in exudates obtained from soil biologically disinfested with ethanol, indicating that physical interaction with
soil microorganisms was not essential. Because acetic acid was confirmed to accumulated during the treatment, we evaluated
the effect of acetic acid amendment against the pathogen in plastic containers. A drop in the soil redox potential seemed
to be correlated with the fungicidal efficacy of acetic acid. Under reductive soil conditions, metal ions such as Mn2+ and Fe2+ formed, and the pathogen was effectively suppressed in Mn2+ and Fe2+ solution. Therefore, Fe2+ and Mn2+ may be the agents that induce suppression of the pathogen during biological soil disinfestation. 相似文献
992.
Background
Safflower (Carthamus tinctorius L.) is a difficult crop to genetically transform being susceptible to hyperhydration and poor in vitro root formation. In addition to traditional uses safflower has recently emerged as a broadacre platform for the production of transgenic products including modified oils and pharmaceutically active proteins. Despite commercial activities based on the genetic modification of safflower, there is no method available in the public domain describing the transformation of safflower that generates transformed T1 progeny.Results
An efficient and reproducible protocol has been developed with a transformation efficiency of 4.8% and 3.1% for S-317 (high oleic acid content) and WT (high linoleic acid content) genotypes respectively. An improved safflower transformation T-DNA vector was developed, including a secreted GFP to allow non-destructive assessment of transgenic shoots. Hyperhydration and necrosis of Agrobacterium-infected cotyledons was effectively controlled by using iota-carrageenan, L-cysteine and ascorbic acid. To overcome poor in vitro root formation for the first time a grafting method was developed for safflower in which ~50% of transgenic shoots develop into mature plants bearing viable transgenic T1 seed. The integration and expression of secreted GFP and hygromycin genes were confirmed by PCR, Southern and Western blot analysis. Southern blot analysis in nine independent lines indicated that 1-7 transgenes were inserted per line and T1 progeny displayed Mendelian inheritance.Conclusions
This protocol demonstrates significant improvements in both the efficiency and ease of use over existing safflower transformation protocols. This is the first complete method of genetic transformation of safflower that generates stably-transformed plants and progeny, allowing this crop to benefit from modern molecular applications.993.
Antonio Evidente Rossitza Rodeva Anna Andolfi Zornitsa Stoyanova Carmen Perrone Andrea Motta 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(2):173-182
Recently, a new fungal disease caused by Diaporthe angelicae (anamorph Phomopsis foeniculi) has been found with increasingly frequency on fennel (Foeniculum vulgare) in Bulgaria. Using a bioassay-guided isolation and purification procedure, different metabolites were isolated from the
fungal culture filtrates. They were identified by spectroscopic methods as nectriapyrone, a pentaketide monoterpenoid, and
altersolanols A and J and macrosporin, three octaketides anthracenones. Leaf puncture bioassay was applied on detached tomato
leaves to prove the phytotoxic activity of the fractions and of pure compounds. Nectriapyrone and altersolanols A and J showed
a modulated phytotoxicity, while macrosporin was not toxic. Altersolanol A was the most active compound. 相似文献
994.
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
995.
Yared Tesfai Tewoldemedhin Mark Mazzola Lizel Mostert Adéle McLeod 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(4):637-651
Cylindrocarpon species are known to be a component of the pathogen/pest complex that incites apple replant disease. In South Africa, no
information is available on apple associated Cylindrocarpon species and their pathogenicity. Therefore, these aspects were investigated. Among the isolates recovered from apple roots
in South Africa, four species (C. destructans, C. liriodendri, C. macrodidymum and C. pauciseptatum) were identified using β-tubulin gene sequencing and phylogenetic analysis. This is the first report of C. liriodendri, C. macrodidymum and C. pauciseptatum on apple trees. Cylindrocarpon macrodidymum was the most prevalent. Isolates within each of the four species were pathogenic towards apple seedlings, but varied in their
virulence. With a single exception, all isolates were able to induce lesion development on seedling roots. Only 57% of the
isolates, which represented all four species, were able to cause a significant reduction in seedling weight and/or height.
The greatest seedling growth reductions were caused by two isolates of C. destructans, and one isolate each of C. liriodendri and C. macrodidymum. A quantitative real-time polymerase chain reaction (qPCR) method was developed for simultaneous detection of all four Cylindrocarpon species. qPCR analyses of Cylindrocarpon from the roots of inoculated seedlings showed that the amount of Cylindrocarpon DNA in roots was not correlated to seedling growth reductions (weight and height) or root rot. The qPCR method is, however,
very useful for the rapid identification of apple associated Cylindrocarpon species in roots. The technique may also hold potential for being indicative of Cylindrocarpon disease potential if rhizosphere soil rather than roots are used. 相似文献
996.
Avia E. Rubin Ayelet-Chen Werdiger Mathias Blum Ulrich Gisi Helge Sierotzki Dietrich Hermann Yigal Cohen 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(2):339-351
Wild type (WT) field isolates of Bremia lactucae failed to germinate in vitro or infect lettuce leaves in the presence of CAA (carboxylic acid amide) fungicides. Minimal
inhibitory concentrations (MIC) for mandipropamid, dimethomorph, benthiavalicarb and iprovalicarb were 0.005, 0.5, 0.5 and
5 μg ml−1, respectively. Mutagenesis experiments showed that spores exposed to EMS (ethyl methane sulphonate) or UV irradiation (254 nm)
could infect lettuce leaves in the presence of up to 100 μg ml−1 CAA. The proportion of infected leaves relative to the number of spores inoculated (infection frequency) was inversely related
to the concentration of CAA used, ranging between 0 and 160 per 1 × 106 spores. Resistant mutants (RM) lost their resistance within 1–14 reproduction cycles on CAA-treated plants. Crosses were
made between RMxWT isolates and RMxRM isolates with an attempt to obtain stable homozygous resistant off-springs. Such crosses
yielded few resistant but unstable progeny isolates. Mutagenic treatments given to hybrid isolates also failed to produce
stable resistance. Previous gene sequencing data showed that stable resistance to CAAs is based on a single SNP in the cellulose synthase 3 (CesA3) gene of Plasmopara viticola. Therefore, we sequenced a 582 bp DNA fragment of Ces3A of WT, RM and hybrid isolates of B.lactucae. No mutation in this gene fragment was found. We conclude that mutagenic agents like EMS or UV may induce resistance to CAA
in Bremia lactucae but this resistance is not stable and not linked to mutations in CesA3 gene. 相似文献
997.
Yan-Xiang Qi Xin Zhang Jin-Ji Pu Xiao-Mei Liu Ying Lu He Zhang Hui-Qiang Zhang Yan-Chao Lv Yi-Xian Xie 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):83-95
Twenty-two isolates of Corynespora cassiicola obtained from cucumber, papaya, eggplant, tomato, bean, Vigna, sesame and Hevea rubber (Hevea brasiliensis) were analysed by morphological features, the differences of the ribosomal DNA internal transcribed spacer (rDNA-ITS) region
sequence and the inter simple sequence repeat (ISSR) technique. Variability of morphological features was observed among the
isolates. Pathogenicity tests showed that isolates from different hosts attacked Hevea rubber. Sequences of two outgroup taxa, C. proliferata and C. citricola, were downloaded from GenBank. The phylogenetic trees were constructed by using the rDNA-ITS region sequences from 24 Corynespora
spp. isolates. In this analysis, the 24 sequences grouped into two clusters (A and B). Cluster A consists of sequences from
all isolates of C. cassiicola; whereas cluster B consists of the two outgroup taxa, C. proliferata and C. citricola. However, the ITS region is conservative, and is not fit for studying differences among isolates. A total of 114 DNA fragments
was amplified with 16 ISSR primers, among which 102 were polymorphic (89.5%). A dendrogram was created by the unweighted pair-group
method with arithmetic averaging (UPGMA) analysis, and 22 isolates grouped into three clusters (C, D and E). Cluster C is
composed of all of the Hevea rubber isolates, whereas cluster D is composed of nine isolates: four from papaya, five from cucumber, eggplant, bean, vigna
and sesame. Cluster E is composed of two isolates from cucumber and tomato. These analyses showed that the genetic diversity
was very rich among the tested isolates. There are no correlations between the morphological characteristics or rDNA-ITS region
sequences of the 22 isolates and their host or geographical origin, but there is a link between ISSR clusters and their host
origins. ISSR markers appear to be useful for intra-species population study in C. cassiicola. 相似文献
998.
Nadia Korolev Mukhiddin Mamiev Tirza Zahavi Yigal Elad 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(4):591-608
Plots in two vineyards in the Golan Heights, Israel were treated with six botryticides during three growing seasons with 3
applications per season. Applications of fenhexamid, pyrimethanil and cyprodinil + fludioxonil were effective, resulting in
52–65% and 53–63% mean reduction in grey mould incidence and severity, respectively. Carbendazim, fluazinam and iprodione
were ineffective or slightly effective. Five hundred and sixteen B. cinerea isolates were collected from infected berries or trapped from the air in the vineyards, and profiles of sensitivity to benomyl,
fenhexamid, fluazinam, fludioxonil, iprodione and pyrimethanil were established for each of the isolates based on a mycelial
growth test. Seventy-four percent of the isolates were sensitive to the six tested fungicides, and the other 26% of the isolates
were classified into 10 phenotypes characterized by resistance to one or more fungicides. Resistant isolates showed fitness
parameters similar or reduced in comparison to sensitive isolates. Resistance to benzimidazoles and to dicarboximides was
the most frequent (up to 25%) and apparently pre-existed in the populations tested. Increased frequency of benzimidazole resistance,
but not dicarboximide resistance, was observed following the 3 years of applications of the fungicides. High level resistance
to pyrimethanil was present at a frequency of about 2% in both vineyards in the first 2 years of the sampling survey and reached
10% in the third year at Site 2. A few isolates were resistant to fenhexamid or fludioxonil (0.8 or 0.2%, respectively). No
strong resistance to fluazinam was detected, although numerous, less sensitive isolates, presumably possessing multi-drug
resistance traits, were recovered at higher frequency from the plots treated with fluazinam than from the untreated plots. 相似文献
999.
Piérri Spolti Luana Schneider Rosa M. V. Sanhueza Jean C. Batzer Mark L. Gleason Emerson Medeiros Del Ponte 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(1):21-29
Sooty blotch and flyspeck is caused by numerous species of fungi that colonize the surface of apple fruit and thereby lower
its market value. Although this disease poses a substantial threat to apple growers’ profitability in some regions, reliable
and cost-effective methods for epidemiological and disease control studies have not been validated, nor are they widely available.
We modified a standard area diagram to aid sooty blotch and flyspeck severity assessments and quantified its impact on accuracy
and precision of visual estimates. Samples of ‘Fuji’ and ‘Mutsu’ fruit were photographed both from the top and laterally.
Severity was assessed from a sub-sample of 160 images using image analysis software. Validation of the diagram was performed
by eight raters who independently assessed severity in two series of selected images representing the lateral view and the
top view, initially unaided and subsequently with the aid of the scale. Severity estimates ranged from 0.4% to 98% (most fruit
had <10% severity). Accuracy and precision of the estimates were significantly improved when using the diagrammatic scale;
concordance correlation coefficient values increased from 0.81 to 0.95. A strong tendency to underestimate severity for the
mid-range to high levels was minimized when using the aid, which also improved reproducibility of the estimates among raters.
In addition to strengthening evidence that a standard area diagram can be used reliably in sooty blotch and flyspeck studies,
we expanded its application to disease assessment in the peduncle region, which enhances the usefulness of the method for
evaluating efficacy of management practices. 相似文献
1000.
Rasa Jomantiene Yan Zhao Ing-Ming Lee Robert Edward Davis 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):97-107
Phytoplasmas infecting sour cherry and lilac in Lithuania were found to represent two lineages related to clover phyllody
phytoplasma (CPh), a subgroup 16SrI-(R/S)C (formerly 16SrI-C) strain exhibiting rRNA interoperon sequence heterogeneity. 16S
rDNAs amplified from the cherry bunchy leaf (ChBL) and lilac little leaf (LcLL) phytoplasmas were identical or nearly identical
to those of operon rrnA and operon rrnB, respectively, of CPh. There was no evidence of 16S rRNA interoperon sequence heterogeneity in either LcLL or ChBL phytoplasma.
Based on collective RFLP patterns of 16S rDNA, ChBL was classified in subgroup 16SrI-R, and LcLL was classified in new subgroup
16SrI-S. The ribosomal protein (rp) gene sequences from LcLL phytoplasma were identical to those of CPh, and strain LcLL was
classified in rp subgroup rpI-C. By contrast, rp gene sequences from ChBL phytoplasma differed from those of subgroup rpI-C;
based on RFLP patterns of rp gene sequences, ChBL was classified in new rp subgroup rpI-O. Single nucleotide polymorphisms
(SNPs), designated here by a new SNP convention, marked members of rp subgroup rpI-C, and distinguished LcLL and CPh from
ChBL and other non-rpI-C phytoplasmas in group 16SrI. The results raise questions concerning phytoplasma biodiversity assessment
based on rRNA genes alone and encourage the supplemental use of a single copy gene in phytoplasma identification and classification,
while drawing attention to a possible role of horizontal gene transfer in the evolutionary history of these lineages. 相似文献