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1.
Phap Q. Trinh Wim M. L. Wesemael Sy T. T. Nguyen Chau N. Nguyen Maurice Moens 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):45-57
The pathogenicity and reproductive fitness of Pratylenchus coffeae and Radopholus arabocoffeae from Vietnam on coffee (Coffea arabica) seedlings cv. Catimor were evaluated in greenhouse experiments. The effect of initial population densities (Pi = 0, 1, 2,
4, 8, 16, 32, 64, 128, and 256 nematodes per cm3 soil) was studied for both species at different days after inoculation (dai). The data were adjusted to the Seinhorst damage
model Y = m + (1-m).zPi-T. Tolerance limit (T) for P. coffeae was zero for the height and the diameter of the coffee plants. For the diameter, the T-value for R. arabocoffeae was 25.6 for 30 and 60 dai and 12.8 for 90 and 120 dai. After 4 months T was zero. The low tolerance limits indicate that
Arabica coffee is highly intolerant to both nematode species. At the end of the experiment (180 dai), all plants were infected
and most were dead when inoculated with R. arabocoffeae at initial densities of 32, 64, 128 and 256 nematodes/cm3 soil. For P. coffeae plant death was already observed at the lowest inoculation densities. Growth of coffee was reduced at all inoculation levels
for both species. Pratylenchus coffeae and R. arabocoffeae caused intense darkening of the roots, leaf chlorosis and a strong reduction of root and shoot growth. It was observed that
P. coffeae mainly destroyed lateral roots rather than tap roots, whereas R. arabocoffeae reduced tap root length rather than the lateral roots. At the lowest inoculum densities, the reproduction factor of P. coffeae was 2.38 and 2.01 for R. arabocoffeae, indicating that arabica coffee is a host for both species. Plant growth as expressed by shoot height and shoot and root
weight measured 60 dai was negatively correlated with nematode (both species) density as expressed by the geometric mean of
nematode numbers at 30 and 60 dai. 相似文献
2.
Experiments were conducted to determine the effectiveness and profitability of the Mi-resistance gene in tomato in suppressing populations of Meloidogyne javanica in a plastic-house with a natural infestation of the nematode. Experiments were also conducted to test for virulence and durability of the resistance. Monika (Mi-gene resistant) and Durinta (susceptible) tomato cultivars were cropped for three consecutive seasons in non-fumigated or in soil fumigated with methyl bromide at 75 g m–2 and at a cost of 2.44 euros m–2. Nematode densities were determined at the beginning and end of each crop. Yield was assessed in eight plants per plot weekly for 6 weeks. The Pf/Pi values were 0.28 and 21.6 after three crops of resistant or susceptible cultivars, respectively. Growth of resistant as opposed to susceptible tomato cultivars in non-fumigated soil increased profits by 30,000 euros ha–1. The resistant Monika in non-fumigated soil yielded similarly (P > 0.05) to the susceptible Durinta in methyl bromide fumigated soil but the resistant tomato provided a benefit of 8800 euros ha–1 over the susceptible one because of the cost of fumigation. Selection for virulence did not occur, although the nematode population subjected to the resistant cultivar for three consecutive seasons produced four times more eggs than the population on the susceptible one. Such a difference was also shown when the resistant cultivar was subjected to high continuous inoculum pressure for 14 weeks. The Mi-resistance gene can be an effective and economic alternative to methyl bromide in plastic-houses infested with root-knot nematodes, but should be used in an integrated management context to preserve its durability and prevent the selection of virulent populations due to variability in isolate reproduction and environmental conditions. 相似文献
3.
Erika Valéria Saliba Albuquerque Poliene Martins Costa Ana Cristina Meneses Mendes Gomes Marcilene Santos Antonio Alves Pereira Michel Nicole Diana Fernandez Maria Fatima Grossi-de-Sa 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(3):365-373
Root-knot nematodes (RKN) are obligate parasite species of the genus Meloidogyne that cause great losses in Arabica coffee (Coffea arabica L.) plantations. Identification of resistant genotypes would facilitate the improvement of coffee varieties aiming at an
environmental friendly and costless nematode control. In this work, the C. arabica genotype ‘UFV 408-28’ was found to be resistant to the most destructive RKN species M. incognita. Pathogenicity assays indicated that the highly aggressive populations of M. incognita races 1, 2 and 3 were not able to successfully reproduce on ‘UFV 408-28’ roots and displayed a low gall index (GI = 2). An
average reduction of 87% reduction of the M. incognita population was observed on ‘UFV 408-28’ when compared to the susceptible cultivar ‘IAC 15’. By contrast, ‘UFV 408-28’ was
susceptible to the related species M. exigua and M. paranaensis (GI = 5 and 4, respectively). Histological observations performed on sections of UFV408-28 roots infected with M. incognita race 1 showed that nematode infection could be blocked right after penetration or during migration and establishment stages,
at 6 days, 7 days and 8 days after infection (DAI). Fluorescence and bright field microscopy observations showed that root
cells surrounding the nematodes exhibited HR-like features such as accumulation of phenolic compounds and a necrotic cell
aspect. In the susceptible ‘IAC 15’ roots, 6 DAI, feeding sites contained giant cells with a dense cytoplasm. Necrotic cells
were never observed throughout the entire infection cycle. The HR-like phenotype observed in the ‘UFV 408-28’—M. incognita interaction suggests that the coffee resistance may be mediated by a R-gene based immunity system and may therefore provide new insights for understanding the molecular basis of RKN resistance
in perennial crops. 相似文献
4.
Anil Kumar Atul Kakrana Anil Sirohi K. Subramaniam R. Srinivasan M. Z. Abdin Pradeep K. Jain 《Journal of General Plant Pathology》2017,83(2):91-97
Root-knot nematodes (RKNs) are one of the most important biotic factors limiting crop productivity in many crop plants. The major RKN control strategies include development of resistant cultivars, application of nematicides and crop rotation, but each has its own limitations. In recent years, RNA interference (RNAi) has become a powerful approach for developing nematode resistance. The two housekeeping genes, splicing factor and integrase, of Meloidogyne incognita were targeted for engineering nematode resistance using a host-delivered RNAi (HD-RNAi) approach. Splicing factor and integrase genes are essential for nematode development as they are involved in RNA metabolism. Stable homozygous transgenic Arabidopsis lines expressing dsRNA for both genes were generated. In RNAi lines of splicing factor gene, the number of galls, females and egg masses was reduced by 71.4, 74.5 and 86.6%, respectively, as compared with the empty vector controls. Similarly, in RNAi lines of the integrase gene, the number of galls, females and egg masses was reduced up to 59.5, 66.8 and 63.4%, respectively, compared with the empty vector controls. Expression analysis revealed a reduction in mRNA abundance of both targeted genes in female nematodes feeding on transgenic plants expressing dsRNA constructs. The silencing of housekeeping genes in the nematodes through HD-RNAi significantly reduced root-knot nematode infectivity and suggests that they will be useful in developing RKN resistance in crop plants. 相似文献
5.
H. Alkher A. El Hadrami K. Y. Rashid L. R. Adam F. Daayf 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(3):505-519
This study examined cross-pathogenicity of the soilborne pathogen Verticillium dahliae between potato and sunflower. Four week-old potato and sunflower seedlings were inoculated with ten isolates from each of
the two host species. Potato cultivars (Kennebec, susceptible, and Ranger Russet, moderately resistant) and sunflower hybrids
(IS8048, susceptible, and 6946, moderately resistant) were assessed for disease severity and percent infection at 2 weeks,
3 weeks, 4 weeks, 5 weeks, and 6 weeks after inoculation (w.a.i), and for vascular discolouration at 6 w.a.i., using visual
scales developed for each host species. The experiments were conducted in 2006 and repeated in 2007. Based on percent infection
and disease severity, most V. dahliae isolates were highly aggressive on both host species. The tested isolates caused higher disease levels in the susceptible
than in the moderately resistant phenotypes. They also caused more vascular discolouration in their original than in the alternative
host. However, the isolates originating from sunflower caused less infection and disease severity on both hosts, compared
to their potato counterparts. Cluster analysis based on all of the criteria used to assess pathogenicity led to three groups
of isolates: (i) most V. dahliae potato isolates, which ranged with the highly aggressive control isolates, (ii) one V. dahliae sunflower isolate, which showed a similar pathogenicity level to the weakly-aggressive V. albo-atrum sub-group II control isolate, with no more symptoms than in the non-inoculated plants, and (iii) most V. dahliae sunflower isolates with mildly- to weakly-aggressive levels. Based on these results, V. dahliae cross-pathogenicity is very effective between potato and sunflower. Therefore, rotations involving these species should be
avoided, especially where sunflower follows potato. 相似文献
6.
Polymnia P. Antoniou Emmanouil A. Markakis Sotirios E. Tjamos Epaminondas J. Paplomatas Eleftherios C. Tjamos 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(4):549-560
An innovative inoculation process, involving the drilling of a trunk hole in 3 year-old olive trees and injecting a dense
conidial suspension of Verticillium dahliae, was developed to study differentiation in foliar symptom expression between olive cultivars tolerant or susceptible to the
pathogen. It was demonstrated that V. dahliae conidia could be translocated and colonize the xylem at the same distance above and below the point of trunk injection in
both cultivars. However, the pathogen could be subsequently isolated at statistically significant percentages in susceptible
cv. Amphissis compared to the tolerant cv. Kalamon, indicating operation of resistance mechanisms in the vascular phase of
the disease. Consequently symptom development in the susceptible cultivar was at least sixfold more intensive compared to
the tolerant cultivar, 6–11 months after trunk inoculation. Perennial olive orchard experiments, aimed at selecting Verticillium-resistant
root-stocks, were conducted by applying the novel method in 2–3 year-old root-stock suckers of Amphissis olive trees and in
the tolerant cvs Lianolia of Corfu and Koroneiki. It was indicated that potentially resistant root-stocks could be obtained
following the trunk drilling technique. Resistance differentiation between cvs Amphissis and Kalamon was further verified
through root inoculation by various V. dahliae microsclerotial concentrations and demonstrated that the trunk drilling inoculation procedure is equally efficient in resistance
evaluation of olives to Verticillium wilt. The trunk inoculation procedure could be useful in selecting and screening root-stocks
for resistance to V. dahliae and other vascular pathogens and could elucidate resistance mechanisms in woody plants against vascular wilt diseases. 相似文献
7.
Margarida Caetano Dias Isabel Luci Conceição Isabel Abrantes Maria José Cunha 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(1):171-179
Plant-parasitic nematodes are serious pests causing important crop losses worldwide. After extensive screening of non-tuber-bearing
Solanaceae, a resistant trap crop, Solanum sisymbriifolium, with a high production level of hatching agents, seemed an ideal control method for potato cyst nematodes (PCN), Globodera spp. Recently, root-knot nematodes (RKN), Meloidogyne spp., were found coexisting with PCN. Therefore, it is important to find alternative methods to control both nematode genera.
The chemical properties of S. sisymbriifolium turns this plant into an excellent candidate for further nematicidal studies and to develop new crop production models. Studies
concerning the effects of this plant on plant-parasitic nematodes are presented. Pathogenicity studies with four S. sisymbriifolium cvs (Domino, Pion, Sis 4004 and Sharp) and five Meloidogyne species showed that all cultivars of S. sisymbriifolium studied were resistant to M. chitwoodi and hypersusceptible to M. arenaria and M. hapla. For M. hispanica only cv Pion was susceptible. M. javanica induced different responses: cvs Pion and Sharp were susceptible; cv Domino resistant and Sis 4004 hypersusceptible. The
studies of the hatching effects of root exudates from these cvs showed that they had an influence on the hatching inhibition
of second stage juveniles of the five Meloidogyne species tested. 相似文献
8.
Y. L. Wu G. J. Yi X. X. Peng 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):409-415
In order to accelerate breeding and selection for disease resistance to Fusarium wilt, it is important to develop bioassays
which can differentiate between resistant and susceptible cultivars efficiently. Currently, the most commonly used early bioassay
for screening Musa genotypes against Fusarium oxysporum f. sp. cubense (Foc) is a pot system, followed by a hydroponic system. This paper investigated the utility of in vitro inoculation of rooted banana plantlets grown on modified medium as a reliable and rapid bioassay for resistance to Foc. Using a scale of 0 to 6 for disease severity measurement, the mean final disease severities of cultivars expressing different
levels of disease reaction were significantly different (P ≤ 0.05). Twenty-four days after inoculation with Foc tropical race 4 at 106 conidia ml−1, the plantlets of two susceptible cultivars had higher final disease severities than that of four resistant cultivars. Compared
with ‘Guangfen No.1’, ‘Brazil Xiangjiao’ is highly susceptible to tropical race 4 and its mean final disease severity was
the highest (5.27). The plantlets of moderately resistant cultivar ‘Formosana’ had a mean final disease severity (3.53) lower
than that of ‘Guangfen No.1’ (4.33) but higher than that of resistant cultivars: ‘Nongke No.1’, GCTCV-119, and ‘Dongguan Dajiao’
(1.87, 1.73, and1.53, respectively). Promising resistant clones acquired through non-conventional breeding techniques such
as in vitro selection, genetic transformation, and protoplast fusion could be screened by the in vitro bioassay directly. Since there is no acclimatization stage for plantlets used in the bioassay, it helps to improve banana
breeding efficiency. 相似文献
9.
Khalid Pervaiz Akhtar Muhmmad Yussouf Saleem Muhammad Asghar Mushtaq Ahmad Nighat Sarwar 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(4):435-450
Sixty-nine tomato genotypes representing nine Solanum species were evaluated for resistance to Cucumber mosaic virus (CMV) subgroup IA and its aphid vector Myzus persicae. Resistance was assessed by visual scoring of symptoms in the field under natural conditions, and in the greenhouse by artificial
inoculations through aphid M. persicae and mechanical transmissions in the year 2007 and 2009. Considerable variation in responses was observed among the evaluation
methods used. Field evaluations were found liable to errors as different levels were observed for the same genotypes in the
different years, however mechanical inoculation was found to be the most useful in identifying CMV subgroup IA resistance,
in contrast aphid transmission was most useful in identifying insect transmission resistance. All genotypes observed as highly
resistant to CMV subgroup IA in the field or through vector transmission became systemically infected through mechanical inoculations.
Using mechanical inoculation, six genotypes (TMS-1 of S. lycopersicum, LA1963 and L06049 of S. chilense, LA1353, L06145 and L06223 of S. habrochaites) were found resistant and another six (L06188 and L06238 of S. neorickii, L06219 of S. habrochaites, L05763, L05776 and L06240 of S. pennellii) were found tolerant showing mild symptoms with severity index (SI) ranging 1-2 and with delayed disease development after
a latent period (LP) of 18–30 days. However, these genotypes were found to be resistant to highly resistant in the field and
through inoculation by M. persicae; and they also supported low population levels of M. persicae except TMS-1. Another nine genotypes (LA2184 of S. pimpinellifolium L., LA2727 of S. neorickii, LA0111, L06221, L06127 and L06231 of S. peruvianum L., LA1306, L06057 and L06208 of S. chmielewskii) showing a susceptible response after mechanical inoculation were highly resistant, resistant and tolerant after M. persicae transmission. The resistant genotypes, identified in the present study can be exploited in the breeding programmes aimed
at developing tomato varieties resistant to CMV subgroup IA and broadening the genetic base of CMV-resistant germplasm. The
differences observed between mechanical and aphid transmission suggests that one should consider both evaluation methods for
tomato germplasm screening against CMV subgroup IA. 相似文献
10.
Polona Strajnar Saša Širca Gregor Urek Helena Šircelj Peter Železnik Dominik Vodnik 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):49-57
Root-knot nematodes (RKN) are obligate endoparasites that severely damage the host root system. Nutrient and water uptake
are substantially reduced in infested plants, resulting into altered physiological processes and reduced plant growth. The
effect of nematode infestation on the morphological changes of roots and subsequent physiological plant responses of infested
tomatoes with the RKN Meloidogyne ethiopica was studied in a pot experiment. Plants were infested with two inoculum densities (10 or 50 eggs per cm3 substrate) and its effect was evaluated 74 and 102 days post inoculation (DPI). Morphological changes and root growth was
determined by analysing scanned images of the whole root system. Nematode infestation reduced the portion of fine roots and
increased that of coarse roots due to gall formation. Fine roots of non-infested control plants represented around 51% of
the area of the whole root system at 74 and 102 DPI. In comparison to controls, plants inoculated with low and high nematode
density had 2.1 and 3.2-times lower surface area of fine roots at 102 DPI. Root analyses revealed that plants had a very limited
ability to mitigate the effects of the root-knot nematodes infestation by altering root growth. Root galls had a major influence
on the hydraulic conductivity of the root system, which was significantly reduced. The low leaf water potential of infested
plants coincided with decreased stomatal conductivity, transpiration and photosynthesis. The latter two were reduced by 60–70%
when compared to non-infested control plants. 相似文献
11.
Natural recovery from wilt disease symptoms was evaluated in young olive trees root dip inoculated with Verticillium dahliae in a growth chamber over a 12 week period and, later on, when the trees were transplanted in a V. dahliae-free soil in a lathhouse during a period of 127 weeks. Recovery in an individual tree was considered when a plant showed
symptom remission after having reached a maximum value of symptom severity. Recovery accounted for 53% of 464 trees that showed
wilt symptoms during observations in the two environments. The remaining trees died. Recurrent wilt symptoms were not observed
in recovered trees, and recovery was usually accompanied by the production of new green tissues. Recovery was clearly higher
in trees inoculated with a non-defoliating (ND) isolate (86.4%) of the pathogen than in those inoculated with a defoliating
(D) isolate (23.9%). The percentage of recovery and the level of resistance were significantly correlated. Recovery accounted
for 92.1% of the cases in resistant and moderately susceptible cultivars, reaching 100% in plants inoculated with the ND isolate
(Table 2); meanwhile it was three times lower (30.1% of the plants) in susceptible and extremely susceptible diseased trees.
In the lathhouse, periodical tissue isolations for monitoring the progress of infections over a period of 127 weeks in recovered
trees, showed that the pathogen could only be isolated from trees 19 weeks after inoculation. Pathogen isolation was significantly
higher from susceptible and extremely susceptible cultivars (84.6%) than from resistant and moderately susceptible ones (33.3%).
Results showed that if a tree overcomes infection by pathogen from a single inoculation, and it is able to begin a recovery
process, it will not express wilt symptoms again in a pathogen-free environment. The pathogen remained inactive or dead over
time in recovered trees. Thus, new infections from rootlets would be necessary for new symptom expression. Recovery from Verticillium wilt is an important natural mechanism that occurs in a high percentage of infected olive trees, and can complement the resistance
of the cultivar, particularly in conditions of low inoculum densities of low virulence isolates of the pathogen in the soil. 相似文献
12.
A survey revealed that Sugarcane yellow leaf virus (SCYLV) is found on all Hawaiian sugarcane plantations including those where no yellow leaf symptoms were observed. In a
comparison of growth and yield between SCYLV-infected and SCYLV-free plants of the cultivar H87-4094, germination and early
shoot growth of infected plants were retarded. The number of stalks per stool was reduced by 30%, biomass was reduced by 29%,
and sugar yield by 26% when plants were harvested after 11 months. Yields did not decrease when plants were harvested after
2 years. Thus, SCYLV could reduce yield, even when the plants were asymptomatic. In a field test of SCYLV-susceptible (infected)
and -resistant cultivars to compare growth and yield, 10 commercial cultivars (six susceptible and four resistant to SCYLV)
were grown in eight fields with different climates and soils. Primary stalk length, biomass and sugar yield did not differ
between susceptible and resistant cultivars under any field conditions. Thus, harmful effects of SCYLV on yield cannot be
deduced by comparing different cultivars. 相似文献
13.
Denilson F. Oliveira Hudson W. P. Carvalho Alessandro S. Nunes Geraldo H. Silva Vicente P. Campos Helvécio M. S. Júnior Alberto J. Cavalheiro 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(1):57-63
The rhizobacterium Paenibacillus macerans was grown in tryptic soy broth and after separating the cells by centrifugation the activity of fractions of the supernatant
was tested against Meloidogyne exigua juveniles. From HPLC analyses and spectral data, the most active fractions were found to contain alanine, glutamic acid,
glycine, histidine, threonine and valine, which were probably produced by bacterial hydrolysis of proteic nutrients. Amino
acids from commercial sources were then assayed to confirm these results and to evaluate their potential for the control of
nematodes. LC50 of 26 and 283 μg ml−1 were shown for the nematicide aldicarb and L-cysteine respectively when tested on M. exigua juveniles. At a concentration 38.4 times>LC50, the amino acid diminished the nematode population on coffee plants to values statistically equal to those obtained with
aldicarb at a concentration 19.2 times>LC50. 相似文献
14.
Black rot, caused by Xanthomonas campestris pv. campestris, (Xcc), is one of the most serious diseases of crucifers world-wide. Forty-nine genotypes were evaluated for resistance under field
conditions in Tanzania after artificial inoculation with Xcc race 1. Open pollinated white cabbage cultivars were generally susceptible, while Portuguese and pointed cabbages exhibited
partial resistance. Some F1 white cabbage cultivars were highly susceptible, whereas others exhibited a high level of partial
resistance. The most promising of the hybrid cultivars were T-689 F1, Gianty F1, No. 9690 F1, N 66 F1, and SWR-02 F1. Breeding
line Badger I-16 exhibited the highest level of resistance of all genotypes. The genotypes accounted for 72.9–75.5% of the
variation of the disease severity when assessed on the leaves, and 71.4% of the variation when assessed as internal black
rot in heads at harvest. High correlations (equal to or above 0.7) were found between disease severities assessed on leaves
three times during the growing season and also with the amount of internal black rot in heads. Leaf loss also was correlated
with disease severity. The high genetic determination of the trait and the high correlations between disease assessments indicate
that selection for resistance to black rot will be efficient when field screenings are carried out. Evaluation of genotypes
for disease severity on leaves during the growing season combined with evaluations of head resistance in the most promising
genotypes may be a simple method to select resistant cultivars. 相似文献
15.
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
16.
Mathias De Backer Hossein Alaei Erik Van Bockstaele Isabel Roldan-Ruiz Theo van der Lee Martine Maes Kurt Heungens 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(3):325-338
Puccinia horiana is the causal agent of chrysanthemum white rust or Japanese rust. This microcyclic autoecious rust has a quarantine status
and can cause major damage in the commercial production of Chrysanthemum x morifolium. Given the international and often trans-continental production of planting material and cut flowers of chrysanthemum and
the decreasing availability of registered fungicides in specific regions, breeding for resistance against P. horiana will gain importance and will need to involve the appropriate resistance genes for the pathotypes that may be present. As
pathotypes have not been well characterized in this system, the main objective was to build an international collection of
isolates and screen these on a large collection of cultivars to identify different pathotypes. Using a robust and high throughput
bioassay, we tested 36 selected cultivars with 22 individual single-pustule isolates of P. horiana. The isolates originated from three different continents over 4 different collection years and included some isolates from
cultivars previously reported as resistant. In most cases the bioassays resulted in a clear scoring of interaction phenotypes
as susceptible or resistant, while in several cases consistent intermediate phenotypes were found, often on specific cultivars.
Twenty-four of the cultivars gave a differential interaction phenotype profile. All isolates produced a unique profile, infecting
a minimum of 4 and a maximum of 19 differential cultivars. Based on the Person analysis of these profiles, this pathosystem
contains at least seven resistance genes (and seven avirulence genes), demonstrating the highly complex race structure in
this pathosystem. 相似文献
17.
Sakhr Ajouz Marc Bardin Philippe C. Nicot Mohamed El Maâtaoui 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(1):31-42
Botrytis cinerea is able to build-up resistance to pyrrolnitrin, an antibiotic produced by diverse biocontrol agents, possibly compromising
the durability of this method of disease control. The development of two near-isogenic lines of B. cinerea differing in their level of resistance to pyrrolnitrin was compared in tomato plants and on PDA medium. In tomato plants,
significant differences in the percentage of infected petioles 1 day after inoculation and in symptom progression on petioles
and stems were observed between the resistant mutant and the sensitive wild-type parent, suggesting a difference in their
level of aggressiveness. Cytohistological investigations revealed that conidia of both near-isogenic lines germinated 6 h
after inoculation and mycelium developed within petiole tissues 12 h after inoculation. However, while the wild-type parent
isolate spread throughout the petiole and rapidly invaded the stem tissues via the leaf-abscission zone 72 h after inoculation, the pyrrolnitrin-resistant mutant failed to extend beyond petiole tissues
to invade the stem. Moreover, 72 h after inoculation, the mycelial development of the pyrrolnitrin-resistant mutant was accompanied
by abnormal glycogen accumulation and chlamydospore-like cell formation. In contrast, wild-type parent mycelium was normally
structured with intensive colonization of stem tissues. Additionally, on PDA medium the mycelium of the pyrrolnitrin-resistant
mutant was less vigorous than the wild-type isolate. These results suggest that the acquisition of pyrrolnitrin-resistance
in B. cinerea is accompanied by changes in mycelial structure and reduction in mycelial growth, leading to a noticeable loss of aggressiveness
on tomato plants. 相似文献
18.
Trifone D’Addabbo Pinarosa Avato Aldo Tava 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):39-49
The nematicidal effect of soil amendments with dry top and root material from Medicago sativa and/or Medicago arborea was evaluated on the root-knot nematode Meloidogyne incognita and on the cyst nematode Globodera rostochiensis in potting mixes. All amendments suppressed root and soil population densities of both nematode species compared to non-treated
and chemical controls. The suppressiveness of M. sativa differed between top and root material and among the amendment rates. In field conditions soil amendments with 20 or 40 t
ha−1 of a pelleted M. sativa meal increased tomato crop yield and reduced soil population densities and root galling by M. incognita. It is suggested that saponins were at least partly responsible for the nematicidal activity. 相似文献
19.
Abstract Brassicaceae plants have the potential as part of an integrated approach to replace fumigant nematicides, providing the biofumigation response following their incorporation is not offset by reproduction of plant-parasitic nematodes on their roots. Forty-three Brassicaceae cultivars were screened in a pot trial for their ability to reduce reproduction of three root-knot nematode isolates from north Queensland, Australia: M. arenaria (NQ1), M. javanica (NQ2) and M. arenaria race 2 (NQ5/7). No cultivar was found to consistently reduce nematode reproduction relative to forage sorghum, the current industry standard, although a commercial fodder radish (Raphanus sativus) and a white mustard (Sinapis alba) line were consistently as resistant to the formation of galls as forage sorghum. A second pot trial screened five commercially available Brassicaceae cultivars, selected for their biofumigation potential, for resistance to two nematode species, M. javanica (NQ2) and M. arenaria (NQ5/7). The fodder radish cv. Weedcheck, was found to be as resistant as forage sorghum to nematode reproduction. A multivariate cluster analysis using the resistance measurements, gall index, nematode number per g of root and multiplication for two nematode species (NQ2 and NQ5/7) confirmed the similarity in resistance between the radish cultivar and forage sorghum. A field trial confirmed the resistance of the fodder radish cv. Weedcheck, with a similar reduction in the number of Meloidogyne spp. juveniles recovered from the roots 8 weeks after planting. The use of fodder radish cultivars as biofumigation crops to manage root-knot nematodes in tropical vegetable production systems deserves further investigation. 相似文献
20.
Vânia M. Freitas Joelma G. P. Silva Cesar B. Gomes José M. C. Castro Valdir R. Correa Regina M. D. G. Carneiro 《European journal of plant pathology / European Foundation for Plant Pathology》2017,148(2):307-319
Meloidogyne enterolobii (syn. M. mayaguensis) has been reported to cause severe damage in commercial guava orchards and other plants in Central and South American countries. Considering the risk of introduction and dissemination of this pest in the European region, M. enterolobii was placed on the EPPO A2 list in 2010. The use of non-host fruit species is a recommended strategy to manage root-knot nematodes in infested guava orchards. This study screened 89 plant genotypes from 25 fruit plants of economic importance, plus two susceptible controls (guava and tomato) for its host status to M. enterolobii. Three to eight months after inoculation, nematode reproduction factor (RF) was used to characterize host suitability of fruit crops to this nematode. Ten banana genotypes, six Barbados cherries, one fig, two grape rootstocks and six melons were rated as good hosts for this nematode. Sixteen fruit plants behaved either as non-hosts or poor hosts to M. enterolobii, including assaí, atemoya, avocado, cashew nut, citrus, coconut, grape, jabuticaba, mango, mulberry, papaya, passion fruit, sapodilla, soursop, starfruit and strawberry. For the future, field experiments in areas infested by this nematode are essential to confirm the greenhouse results. These non-host fruit species can replace in the future eradicated guava trees in fields severely infested by this nematode and become an economic option for growers where M. enterolobii is considered a serious problem. 相似文献