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1.
The response of recombinant inbred lines (RILs) from a cross of zucchini × scallop (Cucurbita pepo subsp. pepo ‘Murcia MU-CU-16’ × C. pepo subsp. ovifera ‘Scallop UPV-196’) to Meloidogyne incognita and M. javanica was determined after completion of a nematode reproduction cycle in experiments carried out in a growth chamber. The nematode differentiated the C. pepo genotypes at the subspecies level due to lower egg mass production on subspecies pepo than ovifera, and thus subspecies pepo was a poorer host than ovifera. In addition, Murcia MU-CU-16 discriminated M. incognita from M. javanica in terms of egg masses (EM), eggs per gram of root and reproduction factor (Rf), whereas Scallop UPV-196 did so in eggs per gram of root and Rf. The RILs differed in gall formation and EM production depending on the nematode × line combination. Comparisons between nematode isolates resulted in four significant combinations for pathogenic potential (galls/initial population (Pi) × 100), seven for parasitic success (egg masses/Pi × 100), and nine for host efficiency (egg masses/galls per root system × 100) which included all the lines tested against both isolates. Lines that restricted nematode development by at least 90% were considered as having intermediate resistance to M. incognita based on the definition of the International Seed Federation. They included lines 28-1, 35A, 107A, 110-3 and 153-2. All the RILs were susceptible hosts for M. javanica. The information presented here will be helpful for nematode management and also for plant breeders working on pathogen resistance on C. pepo. 相似文献
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Sylwia Magdalena Okoń Tomasz Ociepa 《European journal of plant pathology / European Foundation for Plant Pathology》2017,149(3):711-718
The aim of the present study was to determine the virulence structure of powdery mildew of oats (Blumeria graminis DC.f. sp. avena) in Poland in the years 2010–2013. For this purpose, powdery mildew isolates were collected from three experimental stations in Poland. To assess the virulence of the isolates, eight oat varieties with different responses to the pathogen were used. The results showed that a significant proportion of powdery mildew isolates found in Poland overcame the resistance genes of varieties Bruno (Pm6), Jumbo (Pm1) and Mostyn (Pm3). In contrast, lines Av1860 (Pm4), Am27 (Pm5) and Cc3678 (Pm2) were completely resistant to all pathogen isolates involved in the experiment. Changes constantly occurring in the powdery mildew population perfectly reflect diversity indexes, which were the smallest in the first year of observation, where in the following years these parameters were significantly higher. It is worth noting that the presence of powdery mildew is seasonal and local, which is reflected in the prevalence of the disease in a defined area of the country. 相似文献
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Marina Dermastia Dorian Dolanc Petra Mlinar Nataša Mehle 《European journal of plant pathology / European Foundation for Plant Pathology》2018,151(3):791-802
The plant parasitic nematode Longidorus poessneckensis found in Austria, the Czech Republic, Germany, Poland and the Slovak Republic was molecularly characterized. Mitochondrial genes encoding cytochrome c oxidase subunit I (COI) and nicotinamide dehydrogenase subunit 4 (nad4), the D2 and D3 expansion segments of 28S rRNA and Internal transcribed spacer 1 (ITS1) rRNA were sequenced for 16 L. poessneckensis populations. Six haplotypes of COI and five haplotypes of nad4 were determined. Nucleotide intraspecific variation was up to 17.1% for the partial sequenced COI gene and up to 17.7% for the partial sequenced nad4 gene, the latter being the highest up to date known intraspecific variation in this genus. The analyses of multiple amino acid sequence alignments of mitochondrial genes revealed low variability (0–2.4%) for COI gene and high divergence (0–7.6%) for nad4 gene. Intraspecific sequence diversity for the D2-D3 of 28S rRNA gene was up to 1.2% and for ITS1 rRNA gene was up to 1.6%. It has been hypothesized, that during the Last Glacial Maximum, L. poessneckensis populations probably persisted in refuge areas in the Carpathian Mountains and subsequently expanding from these areas and colonizing other European regions. 相似文献
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Juan Carlos Ochoa-Sánchez Fannie Isela Parra-Cota Katia Aviña-Padilla John Délano-Frier Juan Pablo Martínez-Soriano 《Phytoparasitica》2009,37(4):381-384
Mexico is considered to be one of the centers of origin of grain amaranth species. Recently, plants with abnormal anatomical
features were observed in experimental fields established in Central Mexico. The most noticeable symptoms, which consisted
of excessive stem and bud proliferation, mosaics and unusual coloration, suggested that they might be phytoplasma-induced
disorders. Thus, different accessions of grain amaranth (Amaranthus hypochondriacus and A. cruentus) plants were subjected to polymerase chain reaction (PCR) analysis specifically designed to detect these pathogens. Two universal
phytoplasma-specific primer pairs were tested in a nested PCR assay, with primer pair P1/tint (followed by primer pair R16F2/R16R2). Further DNA sequencing analysis of the resulting amplicons indicated that these
phytoplasmas may be related to others already affecting important agricultural crops in Mexico, such as soybean. Data are
presented that disclose the etiology of these syndromes by the use of molecular techniques. To the best of our knowledge,
this finding constitutes the first report of a phytoplasma-related disease in grain amaranth. 相似文献
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《Pesticide biochemistry and physiology》1987,28(3):389-390
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Aleš Lebeda Michaela Sedlářová Marek Petřivalský Jitka Prokopová 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):71-89
Plant pathogenic oomycetes, including biotrophic downy mildews and hemibiotrophs/necrotrophs such as Phytophthora and Pythium, cause enormous economic losses on cultivated crops. Lettuce breeders and growers face the threat of Bremia lactucae, the causal agent of lettuce downy mildew. This pathogen damages leaf tissues and lettuce heads and is also frequent on wild
Asteraceae plants. The interactions of Lactuca spp. with B. lactucae (abbr. lettuce–Bremia) display extreme variability, due to a long co-evolutionary history. For this reason, during the last 30 years, the lettuce–Bremia pathosystem has been used as a model for many studies at the population, individual, organ, tissue, cellular, physiological
and molecular levels, as well as on genetic variability and the genetics of host–parasite interactions. The first part of
this review summarizes recent data on host–parasite specificity, host variability, resistance mechanisms and genetics of lettuce–Bremia interactions. The second part focuses on the development infection structures. Phenotypic expression of infection, behaviour
of B. lactucae on leaf surfaces, the process of penetration, development of primary infection structures, hyphae and haustoria are discussed
in relation to different resistance mechanisms. In the third part, the components of host resistance and the variability of
defence responses are analysed. The role of reactive oxygen species (ROS), antioxidant enzymes, nitric oxide (NO), phenolic
compounds, reorganization of cytoskeleton, electrolyte leakage, membrane damage, cell wall disruption, hypersensitive reaction
and plant energetics are discussed in relation to defence responses. In general, the extreme variability of interactions between
lettuce and Bremia, and their phenotypic expression, results from diversity of the genetic background. Different mechanisms of resistance are
conditioned by an orchestra of defence responses at the tissue, cell, and molecular levels. The various events responsible
for defence involve a complex interaction of the processes and reactions mentioned above. This review also provides an overview
on the timing of pathogen development, host pathological anatomy, cytology and physiology of lettuce–Bremia associations. The significance of these factors on the expression of different resistance mechanisms (non-host and host resistance,
race-specific and race non-specific resistance, field resistance) is discussed. 相似文献
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Bacterial canker is an economically important disease of tomato. Resistance induced by DL-β-Amino butyric acid against bacterial canker caused by Clavibacter michiganensis ssp. michiganensis in tomato plants was investigated. Different doses of DL-β-Amino butyric acid (250–1000 μg ml−1 doses) were tested on 3-week old plants inoculated with a 108 CFU ml−1 bacterial suspension, and disease development was evaluated after inoculation and treatment. Although in vitro growth of the bacteria was not affected by DL-β-Amino butyric acid treatment, foliage sprays of 500 μg ml−1 DL-β-Amino butyric acid significantly suppressed disease development up to 54% by day 14 after inoculation at the four different doses tested. Bacterial populations were reduced by 84% in BABA-treated plants compared to water-treated plants by day 4 after inoculation. Inoculated BABA-treated plants showed significantly higher phenylalanine ammonia-lyase activity, peroxidase activity, and H2O2 concentration than inoculated water-treated plants during day 1 after treatment. These findings suggest that the DL-β-Amino butyric acid treatment resulted in an increase of these enzymes and in H2O2 concentration in planta, and was associated with induction of resistance to bacterial canker. 相似文献
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Vladimír Šašek Miroslava Nováková Petre I. Dobrev Olga Valentová Lenka Burketová 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(1):279-289
Resistance to infection in plants can be induced by treatment with various chemicals. One such compound is β-aminobutyric
acid (BABA). Its positive effect on disease resistance has been noted in several pathosystems. Here we demonstrate that treatment
with BABA protects Brassica napus plants from infection by the fungal pathogen Leptosphaeria maculans. Surprisingly, BABA also displayes in vitro antifungal activity against L. maculans with EC50 similar to the fungicide tebuconazole. Both spore germination and hyphal growth were affected. The toxic effect can be reverted
by addition of trypton to the culture medium. We hypothesised that BABA might inhibit inorganic nitrogen assimilation. Suppression
of disease progression in plants and antifungal activity in vitro was weaker for α-aminobutyric acid and negligible for γ-aminobutyric
acid. In contrast to a resistance inducer benzothiadiazole, the effect of BABA on disease development was nearly independent
of the timing of treatment, indicating possible antifungal activity in planta. On the other hand, quantification of multiple hormones and an expression analysis have shown that treatment with BABA induces
a synthesis of salicylic acid (SA) and expression of SA marker gene PR-1, but no evidence was observed for priming of SA responses to L. maculans. While we have not conclusively demonstrated how BABA suppresses the disease progression, our results do indicate that antifungal
activity is another mechanism by which BABA can protect plants from infection. 相似文献
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A detection method specific for Xanthomonas oryzae pv. oryzae, the pathogen responsible for bacterial blight of rice, was based on the polymerase chain reaction (PCR) and designed by amplifying
the 16S–23S rDNA spacer region from this bacterium. The nucleotide sequence of the spacer region between the 16S and 23S rDNA,
consisting of approximately 580-bp, from X. oryzae pv. oryzae, X. campestris pv. alfalfae, X. campestris pv. campestris, X. campestris pv. cannabis, X. campestris pv. citri, X. campestris pv. cucurbitae, X. campestris pv. pisi, X. campestris pv. pruni and X. campestris pv. vitians, was determined. The determined sequences had more than 95% identity. Therefore, a pair of primers, XOR-F (5′-GCATGACGTCATCGTCCTGT-3′)
and XOR-R2 (5′-CTCGGAGCTATATGCCGTGC-3′) was designed and found to specifically amplify a 470-bp fragment from all strains
of X. oryzae pv. oryzae isolated from diverse regions in Japan. No PCR product was amplified from X. campestris pathovars alfalfae, campestris, cannabis, carotae, cucurbitae, dieffenbachiae, glycines, pisi, pruni, vitians or zantedeschiae, except for pathovars citri, incanae and zinniae. The method could also detect the pathogen in infected rice leaves within 3 hr, at a detection limit of 4×101 cfu/ml.
Received 17 December 1999/ Accepted in revised form 10 April 2000 相似文献
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Lluís Palou Paloma Sánchez-Torres Clara Montesinos-Herrero Verònica Taberner 《European journal of plant pathology / European Foundation for Plant Pathology》2016,145(4):847-856
‘Algerie’ is currently the most important loquat cultivar in Spain. The incidence and etiology of postharvest diseases affecting this cultivar were determined under local conditions. Latent and wound pathogens were evaluated for two consecutive seasons on commercially grown loquats from two orchards. Healthy loquats were either surface-disinfected or artificially wounded in the rind and placed in humid chambers at 20 °C for up to 5 weeks. Additionally, decay was assessed on commercially-handled loquats stored at 5 °C for up to 20 weeks. The most frequent disease was caused by Alternaria alternata, followed by Penicillium expansum. These two pathogens were present on fruit assessed for all types of infection. Moreover, decay caused by Botrytis cinerea was abundantly observed on both wounded and cold-stored fruit, while Colletotrichum gloeosporioides was frequently found on surface-disinfected fruit. Other pathogens that were observed causing latent infection to a lesser extent included Pestalotiopsis clavispora and Diplodia seriata. Common isolates were identified by macroscopic and microscopic morphology and/or DNA amplification and sequencing. Pathogenicity of selected isolates was demonstrated by fulfilling Koch’s postulates and disease development was assessed on artificially inoculated loquats stored at either 20 or 5 °C. 相似文献
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G. A. Matthews 《国际虫害防治杂志》2013,59(4):387-394
Abstract Efficiency of pesticide application can be improved if more consideration is given to where and when the active ingredient is most needed, and the optimum droplet size selected for a given target. Even when minimal volumes of spray are applied concentrate sprays are not justified as a greater proportion of the spray is collected on the target. Sprays with a narrow range of droplet size can be produced from ligaments thrown from centrifugal energy nozzles; droplet size being inversely proportional to the rotational speed. 相似文献
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A new species of Anagyrus Howard (Hymenoptera: Encyrtidae), A. pseudofuscus Zu sp. nov., is described from China as a parasitoid of the mealybug, Phenacoccus solani Ferris (Hemiptera: Pseudococcidae). 相似文献