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1.
Cercospora leaf spot (CLS), caused by Cercospora beticola, is the most destructive foliar disease and is a problem in sugar beet production areas, such as Central High Plains (states of Colorado, Montana, Nebraska and Wyoming) in the United States. The disease can be controlled by strobilurin fungicides, referred to as quinone outside inhibitors (QoIs), with a single target site on C. beticola. Strobilurin resistance has been reported in beet production areas from the United States, including the Central High Plains. Although strobilurin resistance is quantitatively inherited, it is considered that it has low to medium heritability in the population. Effective diagnostic tools are required for the rapid detection of C. beticola strobilurin resistance. The study obtained a partial nucleotide sequence of the C. beticola cytochrome b gene and determined to a putative protein with ~386 amino acid residues. Eighty C. beticola isolates (2004–2011) from the Central High Plains were analyzed for mutations. We found a single nucleotide polymorphic (SNP) site which led to G143A mutation and was present in 2 C. beticola QoI-resistant isolates. Partial sequences obtained from 82 C. beticola QoI-sensitive isolates showed identical cytochrome b gene. We developed a PCR-RFLP assay that involved an in vitro digestion using Fnu4HI restriction enzyme for the rapid molecular detection of G143A mutation in the C. beticola population. Results indicated the PCR-RFLP assay was reliable, sensitive, and can be used for the rapid detection of C. beticola strobilurin resistance.  相似文献   

2.
Fusarium head blight (FHB) is one of the most important fungal diseases affecting wheat worldwide and it is caused mainly by species within the Fusarium graminearum species complex (FGSC). This study evaluated the presence of FGSC in durum wheat from the main growing area in Argentina and analyzed the trichothecene genotype and chemotype of the strains isolated. Also, the genetic variability of the strains was assayed using ISSR markers. Molecular analysis revealed that among the strains isolated and identified morphologically as F. graminearum, there were 14 strains identified as F. cerealis. Also, it revealed that durum wheat grains were mostly contaminated by F. graminearum, being this the only species reported so far, within the FGSC, affecting durum wheat in Argentina. Analysis of molecular variance (AMOVA) indicated a high genetic variability within rather than between F. graminearum populations. All F. graminearum strains presented 15ADON genotype and were able to produce DON while all F. cerealis strains presented the NIV genotype and most of them were able to produce this toxin. The finding of F. cerealis in durum wheat grains indicates the need for investigating if this fungus is the responsible for the NIV contamination found in wheat in Argentina.  相似文献   

3.
Bread wheat (BW) and durum wheat (DW) are both strongly affected by Septoria tritici blotch caused by the hemibiotrophic fungus Zymoseptoria tritici. However, only the BW-Z. tritici pathosystem has been well studied so far. Here, we compared compatible interactions between Z. tritici and both BW and DW species at the cytological, biochemical and molecular levels. Fungal infection process investigations showed close spore germination and leaf penetration features in both interactions, although differences in the patterns of these events were observed. During the necrotrophic phase, disease severity and sporulation levels were associated in both interactions with increases of the two cell-wall degrading enzyme activities endo-β-1,4-xylanase and endo-β-1,3-glucanase as well as protease. An analysis of plant defense responses during the first five days post inoculation revealed inductions of GLUC, Chi4, POX and PAL and a repression of LOX gene expressions in both wheat species, although differences in kinetics and levels of induction or repression were observed. In addition, peroxidase, catalase, glucanase, phenylalanine ammonia-lyase and lipoxygenase activities were induced in both wheat species, while only weak accumulations of hydrogen peroxide and polyphenols were detected at the fungal penetration sites. Our study revealed overall a similarity in Z. tritici infection process and triggered wheat defense pathways on both pathosystems.  相似文献   

4.
Fusarium Head Blight is a major disease of wheat and an important contributor to the reduced cultivation of wheat in South Africa, where the crop often is grown under irrigation. We collected Fusarium isolates from 860 Fusarium Head Blight-infected wheat heads in seven irrigated wheat-growing areas of South Africa. Six Fusarium species, i.e., F. chlamydosporum, F. crookwellense, F. culmorum, F. equiseti, F. graminearum and F. semitectum were recovered, three of which, i.e., F. chlamydosporum, F. equiseti and F. semitectum, were not previously associated with Fusarium Head Blight in South Africa. Fusarium graminearum occurred at high frequencies at all seven locations. Based on polymerase chain reaction (PCR) assays of diagnostic sequences, more isolates were predicted to produce deoxynivalenol than nivalenol. Fusarium graminearum (sensu lato) appears to be the primary causal agent of Fusarium Head Blight in irrigated wheat in South Africa, which may not be the case for wheat cultivated under rain-fed conditions. Rotations of irrigated wheat with other graminaceous crops and maize could increase fungal inoculum and disease pressure. The establishment of Fusarium Head Blight in the irrigated wheat region of the country means that resistant lines and alternative agronomic practices are needed to limit disease severity, yield losses and mycotoxin contamination.  相似文献   

5.
We investigated incidences of Fusarium head blight (FHB) and concentrations of six mycotoxins (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, T-2 toxin, HT-2 toxin and zearalenone) in wheat from 2010 to 2013. Field trials were conducted at the Experimental Station of Cultivar Testing in Chrz?stowo, Poland (53o11’N, 17o35’E). We examined the effects of four agronomic factors, including pre-crop type (corn, sugar beets and wheat), date of sowing (late autumn: November 8–December 9 or spring: March 29–April 19), fungicidal application (untreated or treated with two applications) and cultivar (Monsun, Cytra), on FHB index (FHBi) and mycotoxin levels in order to minimize the risk of wheat grain contamination by mycotoxins via integrated pest management methods. The dominant Fusarium species observed on wheat heads were F. culmorum, F. avenaceum (Gibberella avenacea) and F. graminearum (Gibberella zeae), at 21.1%, 17.2% and 7.1%, respectively. A monthly rainfall sum of 113.9 mm and a relatively low air temperature (monthly average 15.5 °C) resulted in the highest FHBi in untreated wheat (25.1%). Agronomic factors crucial for the FHB incidence were the pre-crop, fungicidal treatments and cultivar selection. In wheat planted after wheat or corn, the FHBi was higher compared with a pre-crop of sugar beet. A double application of fungicides at BBCH 30–32 with prothioconazole and spiroxamine and at a BBCH 65 with fluoxastrobin and prothioconazole effectively reduced the FHBi and mycotoxin concentrations, respectively, in grain. The cultivar ‘Cytra’ had a greater FHBi (10.4%) than ‘Monsun’ (4.6%), and grain infestations by Fusarium species were also greater in ‘Cytra’, at 16.5%, than in ‘Monsun’, at 11.2%. Untreated cv. Cytra grown after corn in spring produced grains with the highest amounts of the mycotoxins, deoxynivalenol, 3-acetyldeoxynivalenol, zearalenone and HT-2 (605, 103, 17.5 and 5.53 μg/kg, respectively). Total mycotoxin levels in wheat were correlated with five determinants: duration of the period between the end of flowering and the beginning of kernel abscission, FHBi, F. culmorum isolation, G. zeae isolation and Fusarium ratio (FR) as a % of total mould isolations. Although, the mean concentration of mycotoxins in grain did not exceed the maximum permissible values for unprocessed wheat our study suggests necessity to monitor and mitigate FHB risk for susceptible cultivars, when wheat spring sowing follows corn or wheat.  相似文献   

6.
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7.
Fungal species comprising the Fusarium graminearum species complex (FGSC) may cause disease in maize and wheat. Host preference within the FGSC has been suggested, in particular F. boothii towards maize ears. Therefore, the disease development and mycotoxin production of five FGSC species in maize and wheat grain was determined. Eighteen isolates representing F. acaciae-mearnsii, F. boothii, F. cortaderiae, F. graminearum and F. meridionale were used. Each isolate was inoculated on maize ears and wheat heads to determine host preferences. Disease severity and disease incidence was measured for maize and wheat, respectively. Fungal colonisation and mycotoxins, deoxynivalenol (DON), nivalenol and zearalenone, was also quantified. Isolates differed significantly (P < 0.05) in their ability to produce symptoms on maize ears, however, no significant differences between FGSC species were determined. Similarly, significant differences (P < 0.05) between isolates but not between FGSC species in disease incidence on wheat were determined. The isolates also differed significantly (P < 0.05) in their ability to colonise maize and wheat grain. No significant differences in fungal colonisation, among the five FGSC species, were determined in field grown maize. However, under greenhouse conditions, F. boothii was the most successful coloniser of maize grain (P < 0.05). In wheat, F. graminearum colonised the grain more successfully and produced significantly more (P < 0.05) DON than the other species. Fusarium boothii isolates were the best colonisers and mycotoxin producers in maize, and F. graminearum isolates in wheat. The selective advantage of F. boothii to cause disease on maize was supported in this study.  相似文献   

8.
Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are important viruses of wheat (Triticum aestivum L.) in the Great Plains of United States. In addition to agronomic practices to prevent damage from these viruses, temperature sensitive resistance genes Wsm1, Wsm2 and Wsm3, have been identified. However, threshold temperatures for Wsm1 and Wsm3 have not been clearly defined. To better understand these two resistance genes, wheat lines C.I.15092 (Wsm1), KS96HW10–3 (Wsm1), and KS12WGGRC59 (Wsm3) were evaluated for WSMV resistance at 27, 30, 33 and 35 °C and for TriMV resistance at 18, 21, 24, 27, 30, 33 and 35 °C. The results showed that only C.I.15092 remained resistant at 30 °C for both viruses. This line also tolerated TriMV at 33 and 35 °C with less sever symptom and lower infection rates. Wheat lines KS96HW10–3 and KS12WGGRC59 hold resistance to TriMV up to 21 °C. Molecular marker results suggested that the resistance in C.I.15092 is most probably conditioned by the resistance gene Wsm1 and additional gene(s) other than Wsm2 and Wsm3.  相似文献   

9.
With the aim of unravelling the role of airborne Fusarium graminearum inoculum in the epidemic of Fusarium head blight (FHB) caused by this species in wheat spikes, a network of Burkard air samplers was set up in five wheat fields distributed in Belgium from 2011 to 2013. Each year from April to July, the daily amounts of F. graminearum inoculum above the wheat canopy were quantified using a newly developed TaqMan qPCR assay. The pattern of spore trapping observed was drastically different per year and per location with a frequency of detection between 9 and 66% and a mean daily concentration between 0.8 and 10.2 conidia-equivalent/m3. In one location, air was sampled for a whole year. Inoculum was frequently detected from the wheat stem elongation stage until the end of the harvesting period, but high inoculum levels were also observed during the fall. Using a window-pane analysis, different periods of time around wheat flowering (varying in length and starting date) were investigated for their importance in the relation between airborne inoculum and FHB parameters (FHB severity, frequency of F. graminearum infection and DON). For almost all the combinations of variables, strong and significant correlations were found for multiple window lengths and starting times. Inoculum quantities trapped around flowering were highly correlated with F. graminearum infection (up to R?=?0.84) and DON (up to R?=?0.9). Frequencies of detection were also well correlated with both of these parameters. DON concentrations at harvest could even be significantly associated with the F. graminearum inoculum trapped during periods finishing before the beginning of the anthesis (R?=?0.77). Overall, these results highlight the key role of the airborne inoculum in F. graminearum epidemics and underline the importance of monitoring it for the development of disease forecasting tools.  相似文献   

10.
Sunflower (Helianthus annuus L.) is an important oilseed crop in South Africa, and is grown in rotation with maize in some parts of North West, Limpopo, Free State, Mpumalanga and Gauteng provinces. Alternaria leaf blight is currently one of the major potential disease threats of sunflower and is capable of causing yield losses in all production regions. Alternaria helianthi was reported as the main cause of Alternaria leaf blight of sunflower in South Africa; however small-spored Alternaria species have been consistently isolated from leaf blight symptoms during recent surveys. The aim of this study was to use morphological and molecular techniques to identify the causal agent(s) of Alternaria blight isolated from South African sunflower production areas. Alternaria helianthi was not recovered from any of the sunflower lesions or seeds, with only Alternaria alternata retrieved from the symptomatic tissue. Molecular identification based on a combined phylogenetic dataset using the partial internal transcribed spacer regions, RNA polymerase second largest subunit, glyceraldehyde-3-phosphate dehydrogenase, translation elongation factor and Alternaria allergen gene regions was done to support the morphological identification based on the three-dimensional sporulation patterns of Alternaria. Furthermore, this study aimed at evaluating the pathogenicity of the recovered Alternaria isolates and their potential as causal agents of Alternaria leaf blight of sunflower. Pathogenicity tests showed that all the Alternaria alternata isolates tested were capable of causing Alternaria leaf blight of sunflower as seen in the field. This is the first report of A. alternata causing leaf blight of sunflower in South Africa.  相似文献   

11.
An extensive survey was carried out to collect Fusarium species colonizing the lower stems (crowns) of bread wheat (Triticum aestivum L.) and durum wheat (T. durum Desf.) from different wheat growing regions of Turkey in summer 2013. Samples were collected from 200 fields representing the major wheat cultivation areas in Turkey, and fungi were isolated from symptomatic crowns. The isolates were identified to species level by sequencing the translation elongation factor 1-alpha (TEF1-α) gene region using primers ef1 and ef2. A total of 339 isolates representing 17 Fusarium species were isolated. The isolates were identified as F. culmorum, F. pseudograminearum, F. graminearum, F. equiseti, F. acuminatum, F. brachygibbosum, F. hostae, F. redolens, F. avenaceum, F. oxysporum, F. torulosum, F. proliferatum, F. flocciferum, F. solani, F. incarnatum, F. tricinctum and F. reticulatum. Fusarium equiseti was the most commonly isolated species, accounting for 36% of the total Fusarium species isolated. Among the damaging species, F. culmorum was the predominant species being isolated from 13.6% of sites surveyed while F. pseudograminearum and F. graminearum were isolated only from 1% and 0.5% of surveyed sites, respectively. Six out of the 17 Fusarium species tested for pathogenicity caused crown rot with different levels of severity. Fusarium culmorum, F. pseudograminearum and F. graminearum caused severe crown rot disease on durum wheat. Fusarium avenaceum and F. hostae were weakly to moderately virulent. Fusarium redolens was weakly virulent. However, F. oxysporum, F. equiseti, F. solani, F. incarnatum, F. reticulatum, F. flocciferum, F. tricinctum, F. brachygibbosum, F. torulosum, F. acuminatum and F. proliferatum were non-pathogenic. The result of this study reveal the existence of a wide range of Fusarium species associated with crown rot of wheat in Turkey.  相似文献   

12.
Fusarium head blight (FHB), mainly caused by Fusarium graminearum species complex (FGSC) and also by other species of this genus, is one of the most destructive cereal diseases with high yield losses and mycotoxin contamination worldwide. The aim of this study was to identify Fusarium species, characterize their virulence factors such as trichothecene genotypes and cell wall degrading enzymes (CWDEs), and also investigate virulence of the isolates obtained from wheat plants with FHB symptoms in Golestan province of Iran. Among 41 isolates tested, 24 were F. graminearum sensu stricto (s.s.), six were F. proliferatum, four were F. culmorum, three isolates belonged to each of F. subglutinans and F. meridionale species and one isolate of F. asiaticum was identified. Among Fusarium isolates, the nivalenol (NIV) genotype could be found more frequently, followed by 3-acetyl deoxynivalenol (3-ADON) and 15-acetyl deoxynivalenol (15-ADON) genotypes. Production of trichothecenes in autoclaved rice cultures was analyzed by gas chromatography (GC) and confirmed by GC–MS. The mean levels of NIV, 3-ADON and 15-ADON produced by Fusarium spp. were 824, 665 and 622 μg kg?1, respectively. All Fusarium isolates were capable of producing CWDEs, mainly cellulase and xylanase. Lipase and pectinase activities appeared later and at less quantities. In overall, the isolates FH1 of F. graminearum and FH8 of F. proliferatum showed the maximum activity of CWDEs, which was correlated with high level of their virulence and aggressiveness on wheat. On the other hand, correlation was observed between the level and type of trichothecene produced by each isolate and its virulence on wheat. Virulence of trichothecene producing isolates was higher than that of non-trichothecene producing isolates. Our results suggested that CWDEs and trichothecenes, as virulence factors, have considerable roles on virulence and aggressiveness of the pathogen. This is the first report on the effect of trichothecenes and CWDEs on virulence and aggressiveness of Fusarium spp. associated with FHB disease in wheat growing regions of Iran.  相似文献   

13.
A method was developed using a Loop-mediated isothermal amplification assay (LAMP) for detecting Didymella bryoniae in cucurbit seeds. The LAMP primers were designed based on the DNA-dependent RNA polymerase II RPB140 gene (RPB2) from D. bryoniae. Calcein was used as an indicator for the endpoint visual detection of DNA amplification. The LAMP assay was conducted in isothermal (65 °C) conditions within 1 h. The detection threshold of the LAMP assay was 10 pg of genomic DNA and D. bryoniae was detected in 100 % of artificially infested seedlots with 0.05 % infestation or greater. With the LAMP assay, 16 of 60 watermelon and muskmelon seedlots collected from Xinjang province were determined to be positive for D. bryoniae. In contrast, a real-time PCR assay determined that 11 of the 60 seedlots from Xinjiang province were positive for the pathogen. These results showed that the LAMP technique was simple, rapid and well suited for detecting D. bryoniae DNA, especially in seed health testing.  相似文献   

14.
Commercial areas containing Eucalyptus plantations have expanded in recent years due to increased demands for pulp, paper and bioenergy. One of the threats that can reduce Eucalyptus production is the eucalyptus rust disease caused by Austropuccinia psidii, a biotrophic fungus that affects a broad range of Myrtaceae. An accurate diagnosis tool for the early detection of rust disease could be useful in breeding programs for selection of resistant plants against rust, in phytosanitary purposes or in rust epidemics studies. The aim of the present work was to develop a SYBR Green-based quantitative real-time PCR (qPCR) assay for the early detection and quantification of A. psidii in Eucalyptus grandis leaves. Three sets of primers based on the A. psidii ribosomal DNA intergenic space region (IGS), beta-tubulin and elongation factor genes were designed and evaluated. The assays using the IGS primer set resulted in the highest detection efficiency, detecting a lower limit of 0.5 pg of A. psidii DNA. Under artificial inoculation in plants, A. psidii was detected immediately after pathogen inoculation until 240 h post-inoculation using qPCR. In field validation of the method, A. psidii was detected using qPCR in naturally infected leaves with or without rust symptoms. This easy and fast method can be used for an efficient detection of A. psidii in E. grandis leaves. The implications of this tool for rust studies are discussed below.  相似文献   

15.
This study was conducted to investigate the Alternaria species associated with leaf spot of date palm and wheat in Oman. Out of 98 date palm leaf samples and 146 wheat leaf samples, Alternaria was isolated from 27 and 23% of the samples developing leaf spot symptoms, respectively. Identification of Alternaria isolates using sequences of the internal transcribed spacer region of the ribosomal RNA (ITS rRNA), glyceraldehyde-3-phosphate dehydrogenase (GPDH), translation elongation factor (TEF) and RNA polymerase II subunit (RPB2) genes, showed that the isolates belong to seven Alternaria species or species complexes. A. burnsii - A. tomato and A. arborescens species complexes (58 and 4%, respectively) and A. alternata (38%) were the species recovered from the symptomatic date palm leaves. A. alternata (67%), A. burnsii - A. tomato species complex (15%), A. jacinthicola (3%), A. ventricosa (3%), A. slovaca (6%) and Alternaria caespitosa (6%) were isolated from wheat. Pathogenicity test showed that tested isolates of A. alternata (DPM19, WDK12), A. burnsii - A. tomato species complex (DPM31), A. jacinthicola (WBR4) and A. slovaca (WDK9, WDK7) were pathogenic on date palm, while A. alternata (DPM19, WDK12), A. burnsii - A. tomato species complex (DPM31, WDK11) and A. slovaca (WDK9, WDK7) were pathogenic on wheat. This is the first report of date palm and wheat as new hosts for A. burnsii - A. tomato species complex and the first reports of A. burnsii - A. tomato species complex, A. caespitosa A. slovaca, and A. ventricosa in Oman. The study shows that several species of Alternaria are associated with leaf spot in date palm and wheat in Oman, with some isolates having the ability to cause infection in both hosts.  相似文献   

16.
Sixty two rhizospheric and endophytic bacterial strains were evaluated for their biocontrol effect on two aggressive Fusarium culmorum isolates (Fc2 and Fc3). We observed that 35 % and 23 % of the tested strains inhibited the in vitro growth of Fc2 and Fc3 respectively. The observed antagonism was due to inhibition by contact (13–19 % of the strains) or at distance (10–16 % of the strains) for both fungal isolates. Some of the antagonistic bacteria showed the ability to produce diffuse and/or volatile compounds that inhibit the growth, the sporulation and macroconidia germination of F. culmorum. None of the tested antagonistic bacteria showed chitinase activity on synthetic medium. The sequencing of the 16S rDNA genes of some antagonistic bacteria showed that they belong to the genera Bacillus, Pseudomonas and Microbacterium. The double inoculation of durum wheat seeds by the antagonistic bacterial strains (B13, B18, BSE1, BSE3 and B16E) and the two F. culmorum isolates showed that germination and seedling vigor were generally improved in vitro. The percentage of infected seeds was also reduced. In greenhouse trials, the biocontrol effectiveness of F. culmorum was dependant from the virulence of the fungal strain and the specificity of the antagonistic interaction between bacterial and fungal strains. The bacterial strains B18 and B16E reduced F. culmorum infection on durum wheat plants probably due to their antagonistic and plant growth promoting activities and they may be used in a mixture as seed biopriming inoculum for plant growth bio-promoting and Fusarium wheat diseases biocontrol.  相似文献   

17.
Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat in Canada. This study presents the results from resistance evaluation of Yr genes and western Canadian wheat cultivars from different milling classes, to natural infection in southern Alberta and British Columbia which are considered hot spots of stripe rust occurrence in Canada, due to proximity to Pacific Northwest of the United States where stripe rust epidemics are frequent. Genes Yr1, Yr5, Yr15, and YrSP were effective in all environments; Yr17 and Yr28, which were earlier reported ineffective to existing stripe rust races at the seedling stage in Canada, were effective at adult plant stages in most of the environments because of warmer climates in southerly locations, a favourable condition for expression of the genes. Yr17 is common in winter wheat cultivars and only reported spring wheat cultivar carrying it is CDC Stanley, which can serve as donor parent in breeding programs. Gene Yr24/26 was not very effective in western prairies although reported as effective in eastern prairies. Residual resistance from combination of defeated genes (Yr3, Yr7, Yr9, Yr27) in some supplementary differentials was observed. Most cultivars carry slow-rusting, pleiotropic adult-plant resistance gene Yr18 and some Yr29, which were effective in some locations. These genes failed to provide complete protection under high disease pressure. Seedling and adult plant resistance genes Yr5, Yr15, Yr17 and Yr18, Yr36, respectively could be good targets for resistance breeding. Stacking adult plant resistance genes with seedling resistance genes can provide durable resistance to stripe rust.  相似文献   

18.
Wheat leaf rust caused by Puccinia triticina (Pt) is one of the most severe fungal diseases threatening the global wheat production. The use of leaf rust resistance (Lr) genes in wheat breeding programs is the major solution to solve this issue. Wheat isogenic line carrying the Lr39/41 gene has shown a moderate to high resistance to most of the Pt pathotypes detected in China. In the present study, a typical hypersensitive response (HR) was observed using microscopy in leaves of the Lr39/41 isogenic line inoculated with the avirulent Pt pathotype THTT from 48 h-post inoculation. Two Lr39/41 resistance-associated suppression subtractive hybridization (SSH) libraries with a total of 6000 clones were established. Microarray hybridizations were performed on all obtained SSH clones using RNAs extracted from leaves of the Pt-inoculated and non-inoculated Lr39/41 isogenic lines, and leaves of the Pt-inoculated and non-inoculated Thatcher susceptible lines. Differentially expressed clones were analyzed by significance analysis of microarrays (SAM), followed by further sequencing. A total of 36 Lr39/41-resistance-related differentially expressed genes (DEGs) were identified, many of which had been previously reported to be involved in the plant defense response. The expression levels of eight selected DEGs during different stages of the Lr39/41-mediated resistance were further quantified by a qRT-PCR assay. Several pathogenesis-related (PR) and HR-related genes seem to be crucial for the Lr39/41-mediated resistance. In general, a brief profile of DEGs associated with the Lr39/41-mediated wheat resistance to Pt was drafted.  相似文献   

19.
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20.
A series of studies were carried out on Colletotrichum lentis which had been been identified in 2015 based largely on the distinctive shape of conidia and ITS sequences, and which has been causing severe anthracnose disease symptoms on common vetch plants (Vicia sativa) in Gansu Province in the northwest region of China. A key focus of the present studies was to determine how vetch crops become infected. The addition of residues from harvested common vetch crops to land being prepared as a seedbed was shown to result in the highest levels of disease severity indicating that this management practice was the most likely way for crops to become severely infected. Seed transmission was unlikely to be the cause of severe outbreaks as less than 5% of seeds harvested from severely infected plants carried C. lentis. To verify that the species causing the severe outbreaks of anthracnose disease of vetch crops was C. lentis, sequence analysis of the ITS, TUB2, ACT, HIS3 and GAPDH genes was conducted. C. lentis isolates from common vetch and lentil (Lens culinaris) formed a distinctive group among Colletotrichum species, including those species that infect other forage and field crops. The unique shape of conidia of C. lentis, straight with only one end curved, was confirmed as being reliable for rapid identification of disease outbreaks caused by this damaging fungal pathogen.  相似文献   

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