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1.
Carla M. R. Varanda Marta S. M. R. Silva Maria do Rosário F. Félix Maria Ivone E. Clara 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(2):165-172
Transmission of three strains of OMMV by an Olpidium sp. was evaluated and compared. The three strains were 1) an OMMV wild type (WT) recovered from olive trees, 2) an OMMV variant
(L11) obtained after 15 serial passages of single local lesions induced in Chenopodium murale plants, and 3) a construct OMMV/OMMVL11 in which the coat protein (CP) gene replaced that of the wild type. A single-sporangial
culture derived from Chinese cabbage (Brassica pekinensis) used as a bait plant grown in soil of an olive orchard, was identified as Olpidium brassicae based on the size and sequence of the generated amplicon in PCR specific tests. Each of the three virus strains was soil
transmitted to cabbage roots in the absence of the fungus at similar rates of 30 to 40%. Separate plant inoculation by O. brassicae zoospores incubated with each viral strain resulted in enhanced transmission of OMMV, reaching 86% of infection whereas that
of the other two strains remained practically unaffected at ca. 34%. Binding assays showed that the amount of virus bound to zoospores, estimated spectrophotometrically, was 7% in the
case of OMMV, and practically nil in the case of the other two viral strains. Substitution of the coat protein (CP) gene of
OMMV by that of the OMMV L11 strain, drastically reduced viral transmissibility in the presence of zoospores to the level
of that observed in their absence. Our data shows that OMMV soil transmission is greatly enhanced by O. brassicae zoospores and that the viral CP plays a significant role in this process, most likely by facilitating virus binding and later
entrance into the host plant roots. 相似文献
2.
Ana Alfaro-Fernández Amparo García-Luis 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):73-85
Muskmelon (Cucumis melo cv. Temprano Rochet) and autumn squash (Cucurbita maxima) seedlings were inoculated either with Acremonium cucurbitacearum or Monosporascus cannonballus, two of the soil-borne fungi implicated in ‘melon collapse’. Inoculation was achieved in two different ways: by growing the
plants in pots containing infested soil to study the histological changes produced in the infected tissues using light microscopy
and by growing seedlings in Petri dishes together with fungal colonies in order to observe the colonisation of the plant tissues
using scanning electron microscopy. Both muskmelon and autumn squash roots infected with A. cucurbitacearum showed a suberised layer in the epidermis and the outermost layers of the parenchymatic cortex, but these symptoms developed
earlier in the muskmelon plants. Muskmelon plants infected by this fungus also presented hypertrophy and hyperplasia, which
led to a progressive separation of the vascular bundles in the lower stems of the affected plants. This response was not observed
in autumn squash during the study. On the other hand, few histological changes were observed in tissues infected with M. cannonballus and only a slight increase in the size of cortical intercellular spaces was noted in the lower stems of muskmelon plants,
and infected autumn squash tissues remained free of these symptoms throughout the study. The scanning electron microscope
observations revealed that both fungi were able to colonise the tissues of the two host plants which were studied. A. cucurbitacearum colonised the epidermis and cortex of both muskmelon and autumn squash. The hyphae grew both inter- and intracellularly,
and the density of the colonisation decreased within the endodermis. The same colonisation of host plants was observed as
a result of M. cannonballus infection. The xylem vessel lumina of both muskmelon and autumn squash showed hyphae and tylose formation as a result of
both fungal infections. However, non-fungal structures were detected in the hypocotyl vascular tissues. The present study
demonstrates that both fungi are capable of infecting the tissues of a species which is resistant (autumn squash) and a species
which is susceptible (muskmelon) to melon collapse. 相似文献
3.
Pymetrozine, a novel compound belonging to the class pyridine-azomethines, is a feeding inhibitor labeled for use against
plant pests in the order Hemiptera. Pymetrozine was evaluated for its ability to interfere with whitefly transmission of the
begomovirusTomato yellow leaf curl virus (TYLCV). Pymetrozine was applied as Fulfill
TM
50 WG at two rates (0.291 and 0.582 g formulationl
−1) to tomato seedlings with four to six true leaves. Viruliferous whiteflies (three to five per plant) were added 1, 4, 7 and
11 d after a single application of pymetrozine, and transmission rates were determined 4 wk after the addition of whiteflies.
Pymetrozine provided protection against transmission of TYLCV by viruliferous whiteflies for up to 1 wk after a single apliation.
No phytotoxicity was observed on tomato transplants. These results indicate that pymetrozine could be an effective tool for
tomato transplant producers to protect susceptible transplants from infection by begomoviruses, such as TYLCV. Pymetrozine
might also work well as part of an integrated approach to begomovirus management in greenhouse tomato fruit production.
http://www.phytoparasitica.org positing Oct. 20, 2003. 相似文献
4.
Yingqin Liu Ayami Kanda Akinori Kiba Yasufumi Hikichi Kouhei Ohnishi 《Journal of General Plant Pathology》2009,75(5):362-368
Sequence analysis of hrp loci and effector genes in the flanking regions showed significantly high similarities between two phylotype I strains of
Ralstonia solanacearum, GMI1000 and Japanese strain OE1-1. Further sequence analysis of the distribution of avrA and popP1, known as determinants of a hypersensitive response (HR) induction on Nicotiana tabacum (tobacco), in 22 Japanese phylotype I strains revealed that all strains had one of the two distinct avrA alleles and that 10 strains had an identical popP1 but the other 12 did not. After infiltration of tobacco leaves, more than half of these 22 strains elicited HR. In combination
with the ability to induce HR, avrA and popP1 are thus not likely to be the sole determinants of HR in Japanese phylotype I strains. 相似文献
5.
From the genome of a Japanese field isolate of the rice blast fungus, Magnaporthe oryzae, we newly identified Inago1 and Inago2 LTR retrotransposons. Both elements were found to be Ty3/gypsy-like elements whose copies were dispersed within the genome of Magnaporthe spp. isolates infecting rice and other monocot plants. Southern hybridization patterns of nine re-isolates derived from conidia
of the strain Ina168 produced after a methyl viologen treatment were not changed, indicating that the insertion pattern of
Inago elements is relatively stable. 相似文献
6.
Xiu-Fang Hu Fei-Xiang Ying Yu-Bo He Yuan-Yuan Gao Hai-Min Chen Ji-Shuang Chen 《European journal of plant pathology / European Foundation for Plant Pathology》2008,120(3):305-310
Pinellia ternata is a traditional Chinese herb which has been used in China for over 1,000 years. A soft-rot disease characterized by water-soaked
lesions and soft-rot symptoms with a stinking odour was commonly observed in cultivated fields of this plant, and Pectobacterium-like bacteria were consistently isolated from the infected tissues. Two typical strains (SXR1 and ZJR1), isolated from Shanxi
and Zhejiang, respectively, were identified. Pathogenicity tests revealed that these strains were virulent to P. ternata and induced the same symptoms as observed in the field. Characterization involving fatty acid profile, metabolic and physiological
properties, 16S rDNA sequence and PCR-RFLP identified both isolates as P. carotovorum subsp. carotovorum (Pcc). The 16S rDNA of both isolates shared 97–99% sequence similarity with that of Pcc strains. The phylogenetic trees showed
that both isolates were clustered in the group of Pcc and P. carotovorum subsp. odorifera and both PCR-RFLP profiles were consistent with the pattern E produced by the minority of Pcc strains. Thus, isolates SXR1
and ZJR1 were characterized as Pcc in spite of some differences. This is the first report that Pcc has been proven as a causal
agent of soft-rot disease on P. ternata. 相似文献
7.
Federica Bini Klaus Geider Carlo Bazzi 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(3):403-411
Tumour tissue samples were collected from vines grown in various regions of Italy and other parts of Europe and extracted
for detection of Agrobacterium vitis. Fifty strains were isolated on agar plates and screened by PCR with consensus primers from the virD2 gene. They were confirmed as A. vitis with a species-specific monoclonal antibody. The isolates were further analyzed by PCR for their opine synthase genes and
ordered into octopine, nopaline and vitopine strains. Primers designed on the octopine synthase gene did not detect octopine
strains of Agrobacterium tumefaciens. For quantitative PCR, virD2 fragments were sequenced: two classes of virD2 genes were found and two primer sets designed, which detected octopine and nopaline strains or only vitopine strains. For
simultaneous identification of all opine-type strains, multiplex real-time PCR with either primer pair and SYBR Green was
performed: the combined sets of primers gave signals with DNA from any A. vitis strain. Specificity of the new primers for real-time PCR was evaluated using several unidentified bacterial isolates from
grapevines and other plant species. An elevated level of non-specific background was observed when the combined primer sets
were used in multiplex PCR assays. The real-time PCR protocol was also used to detect A. vitis cells directly from grapevine tumours; avoiding direct isolation procedures a sensitivity in the range of one to ten cells
per assay was found. Inhibition of the PCR reaction by plant material was overcome by treating tumour extracts with a DNA
purification kit as a step for the isolation of nucleic acids. 相似文献
8.
Joanna Puławska Monika Kałużna 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(2):379-390
The genetic diversity of 47 strains of Agrobacterium originating from different host plants and geographical locations in Poland, together with 12 strains from other countries
was investigated. It was analyzed using RFLP of DNA fragment amplified with primers UP-1 and UP-2r flanking part of gyrB and parE genes, gyrB sequencing and randomly amplified polymorphic DNA (RAPD) technique. On the basis of obtained results, we found the majority
of agrobacteria isolated in Poland belong to biovar 2. However, among others, three strains distinct from type strains of
all the known Agrobacterium species, were discovered. All three methods showed no correlation between genetic diversity and geographical origin or the
host plant of all studied strains but they revealed high diversity of the tested agrobacteria. The highest diversity was observed
within strains of biovar 1, whereas those of biovar 2 were found to be the more homogenous group. The topology of the constructed
gyrB tree corresponds to topologies of 16S and 23S rDNA trees obtained in this and other studies, but the gyrB tree had deeper branching. In the case of RAPD, it was possible to find a unique DNA fingerprint for almost each strain
tested. The gyrB gene appeared to be a good phylogenetic marker with high discrimination power allowing better differentiation between species
and strains, whereas the RAPD technique can serve as a tool for single strain typing. 相似文献
9.
Mitsuro KAMEYA-IWAKI Kimiaki MURAKAMI Shin-ichi ITO Kaoru HANADA Shuhei TANAKA 《Journal of General Plant Pathology》2000,66(1):64-67
Sequential transmission tests of Peanut stunt virus (PSV) and Cucumber mosaic virus (CMV) systemically infecting common bean, Phaseolus vulgaris, were conducted using Myzus persicae allowed to fast for 2 hr and then to acquisition feed on infected common bean plants or purified virus for 10 min. In the
sequential transmission tests using either one or 10 aphids per assay plant, three isolates of PSV (J,S,Y5) and one of CMV
(V) were transmitted from and to common bean up to a third or fourth inoculation access. Many aphids transmitted these viruses
to two or three plants. Purified viruses of PSV-S and CMV-V were also transmitted up to a third or second inoculation access
at low percentage. On tobacco, Nicotiana tabacum, aphids transmitted PSV-S and CMV-V only in the first inoculation access, although PSV-S was transmitted to only one plant
in the fourth and fifth inoculation access. These viruses may be transmitted in two phases by aphids, depending on the plant
species.
Received 16 April 1999/ Accepted in revised form 1 September 1999 相似文献
10.
Shiori Okuda Mitsuru Okuda Shohei Matsuura Shinichiro Okazaki Hisashi Iwai 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(2):355-362
The vector competence of Frankliniella occidentalis for Chrysanthemum stem necrosis virus (CSNV) was evaluated. Three vector strains with distinct competences for Tomato spotted wilt virus (TSWV) transmission were investigated, including an artificially selected strain (TsH) that has a particularly high competence (>90 %). Newly hatched larvae of F. occidentalis were given an acquisition access period of 5 days on CSNV-infected D. stramonium leaves, and reared to maturity. Their transmission efficiencies were examined using a leaf disk assay using Petunia x hybrida leaves. Following the leaf disk assay, the virus accumulation in the vectors was examined via a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) of their bodies. The results showed that the CSNV acquisition and transmission efficiency of the TsH strain did not differ from those of the others, indicating that the competence of F. occidentalis as a vector for CSNV is not related to that for TSWV. The CSNV transmission and acquisition efficiencies of two F. intonsa strains (Hiroshima and Fukuoka) were also evaluated. In Hiroshima strain, 35 % of adults were viruliferous, but only two transmitters (3 %) were observed. In Fukuoka strain, 6 % were viruliferous, and no transmitters were observed. These results indicate that F. intonsa cannot be a major vector for CSNV. The accumulation of CSNV in the adults of F. occidentalis and F. intonsa evaluated using DAS-ELISA showed a significant difference in ELISA values among transmitter, viruliferous non-transmitter, and non-viruliferous individuals. These results clearly demonstrated that only transmitters that accumulated a threshold quantity of virus can transmit CSNV to plants. 相似文献
11.
Johanna J. van der Merwe Teresa A. Coutinho Lise Korsten Jacqueline E. van der Waals 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(2):175-185
In South Africa during the 2006/2007 potato growing season, outbreaks of blackleg occurred, causing severe economic losses
in commercial potato production fields. Symptoms were initially observed on only one stem per plant, on which the top leaves
rolled upwards, wilted and became necrotic. As symptoms progressed to the lower leaves with subsequent leaf desiccation, a
light to dark brown discolouration of the vascular system at the stem base developed, followed by external darkening. Under
prevailing wet and humid conditions stems became slimy and pale. In the stems, the pith became necrotic and hollow. These
symptoms were similar to those described in Brazil, where the causal agent was identified as a new subspecies, Pectobacterium carotovorum subsp. brasiliensis (Pbcb). Isolations from plants showing typical blackleg symptoms were made on CVP medium. Sequences and phylogenetic analysis of
the partial 16S–23S rDNA intergenic spacer region indicated that the isolates were Pbcb. Comparison of PCR-RFLP patterns of the 16S–23S rDNA of isolates to reference cultures confirmed the identity of the South
African blackleg strains as Pbcb, identical to strain 8 isolated in Brazil. This is the first report of Pbcb in South Africa and it appears to be the most important causal agent of blackleg in South Africa. The disease poses a major
potential threat to the South African potato industry especially in terms of seed exports, tuber quality and yield. 相似文献
12.
Shohei Matsuura Yosuke Matsushita Reiko Kozuka Sachiko Shimizu Shinya Tsuda 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(1):111-115
Quantitative PCR revealed that Tomato chlorotic dwarf viroid (TCDVd) was present in substantial amounts in viroid-infected tomato flowers. Healthy tomato plants were arranged in two
different glasshouses, and plants were mechanically inoculated with TCDVd. Bumblebees (Bombus ignitus) were then introduced into the glasshouses to reveal whether the viroid was transmitted from infected source plants to neighbouring
healthy plants. TCDVd infection was found in neighbouring tomato plants more than 1 month after the introduction of the bees,
some of which expressed symptoms, in both glasshouses. Thus, bumblebees transmitted TCDVd from tomato to tomato by pollination
activities. 相似文献
13.
14.
Domenico Rongai Claudio Cerato Luca Lazzeri 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(4):613-619
This study examines the effects of a vegetable fungicide on sugar beet powdery mildew (Erysiphe betae) and cucumber powdery mildew (Erysiphe cichoracearum). The formulations consisting of a dispersion of Brassicaceae meal in vegetable or mineral oils on infected leaves of sugar beet, reared in the greenhouse, and of musk melons cultivated
under plastic tunnels, were tested in comparison to each oil taken separately. Both formulations containing Brassicaceae meals, caused 94% of conidia to be distorted while for the untreated group only 2% were distorted. Furthermore, the leaf
area infected by E. betae was 56% for untreated plants and 2.7 and 9.9% respectively, for plants treated with meal containing mineral and vegetable
oil. Vegetable oil considered separately or with Brassicaceae meals showed no phytotoxicity, while the formulations based on mineral oil showed a significantly lower fresh and dry weight
on tomato plants. The low level or absence of phytotoxicity of plants treated with vegetable oil formulations suggests that
to improve the efficacy of powdery mildew control, they could be used mixed with sulphur. The efficiency of the vegetable
formulations in the powdery mildew control observed during these trials encourages further investigation on other parasitic
fungi and foliar pathogens. 相似文献
15.
A total of 88 strains of Erwinia carotovora subsp. carotovora (Ecc) isolated from various host plants in several geographic regions were screened for production of antibacterial substances using the same strains as indicators. Of the 88 strains, 72 produced antibacterial substances. One of these 72 strains, a Brazilian strain Ecc 32, produced an antibacterial substance active against all tested Ecc strains on TSA medium. The antibacterial spectrum of the compound from Ecc 32 strain was limited to closely related strains of soft-rot Erwinia species. Such a narrow spectrum of activity is typical of bacteriocins. The compound produced by Ecc 32 strain, however, was resistant to some enzymes and detergents. Moreover, the compound was heat-stable and active over a wide pH range. The physical characteristics of the compound were not in agreement with those of bacteriocin or carotovoricin. 相似文献
16.
Nurul Shamsinah Mohd Suhaimi Rozeita Laboh Noni Ajam Kwai Lin Thong 《European journal of plant pathology / European Foundation for Plant Pathology》2017,148(1):13-26
A blood disease pathogenic strain, Ralstonia syzygii subspecies celebesensis was used to study the possible association of biofilm-forming bacteria with the development and severity of blood disease in banana plants. Therefore, the objective of this study was to determine the effects of mono-culture and co-culture inoculation of isolated biofilm-forming bacteria with the blood disease pathogen in banana pseudostems in glasshouse conditions. Putative biofilm-forming bacteria were isolated from an infected banana plant and were further identified using 16SrRNA sequencing. Four isolates, identified as Enterobacter hormaechei, Enterobacter cloacae, Kosakonia radicincitans and Klebsiella pneumoniae, were inoculated as a mono- and co-culture with R. syzygii subsp. celebesensis into 2 months old banana plants. The observation after the 8 weeks of post inoculation showed that plants which were co-inoculated with the pathogen and K. radicincitans, a biofilm-forming bacterium, were the most susceptible towards the infection. In contrast, plants under two treatments (which were co-inoculated with the pathogen and E. cloacae and the pathogen with E. hormaechei) were less susceptible towards the infection. This study revealed the antagonistic effects of two biofilm-forming strains which reduced the severity of infection caused by the pathogenic agent. Scanning electron micrographs of the cross section of plant rhizomes indicated the dissimilarity of adhesion and host colonization conditions of the pathogen in each infected plant from different treatments. 相似文献
17.
The ability of selected strains of fluorescent Pseudomonas spp. to cause induced systemic resistance (ISR) in Eucalyptus urophylla against bacterial wilt caused by Ralstonia solanacearum was investigated. Four of the five strains used can produce salicylic acid (SA) in vitro and, therefore, chemical SA, that is known to induce resistance in many plant species, was used as a reference treatment.
Whereas a soil drench with SA did induce systemic resistance in E. urophylla, infiltration of SA into leaves did not. None of the fluorescent Pseudomonas spp. strains caused ISR against bacterial wilt when applied to the soil, but two strains, P. putida WCS358r and P. fluorescens WCS374r triggered ISR when infiltrated into two lower leaves 3–7 days before challenge inoculation. A mutant of strain WCS358r
defective in the biosynthesis of the fluorescent siderophore pseudobactin, did not cause ISR, while the purified siderophore
of WCS358r did, suggesting that pseudobactin358 is the ISR determinant of WCS358. A siderophore-minus mutant of WCS374r induced
the same level of disease resistance as its parental strain, but the purified siderophore induced resistance as well, indicating
that both the siderophore and another, unknown, inducing determinant(s) of WCS374r can trigger ISR in Eucalyptus. A possible role of WCS374r-produced SA remains uncertain. Transformation of a siderophore-minus mutant of WCS358 with the
SA biosynthetic gene cluster from WCS374 did not enable this transformant to cause ISR in E. urophylla. 相似文献
18.
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
19.
Fusarium species are soil-borne fungal pathogens that produce a variety of disease symptoms when attacking crop plants. The mode of root colonization of Eucalyptus viminalis seedlings by a pathogenic F. oxyporum strain (Foeu1) at the ultrastructural level and changes in cell wall pectin during host pathogen interactions are described. Root systems of E. viminalis plants were inoculated with F. oxysporum in an in vitro model system. Hyphae of F. oxysporum adhered to the outer epidermal cell walls through fibrillar material, and after penetration they spread into the internal tissues. They developed intercellularly and intracellularly in the root cortex and invaded vascular tissues. Papillae were induced, and the host plasma membrane ruptured in colonized cells, causing rapid host tissue and cell damage. Changes in distribution and occurrence of nonesterified and methyl-esterified pectins were evaluated after root colonization by F. oxysporum using two monoclonal antibodies, JIM 5 and JIM 7, respectively. Nonesterified pectin in control roots was mainly localized in the epidermal cell walls and middle lamellae in parenchymal cortex, whereas methyl-esterified pectin accumulated more in primary cell walls of the cortex and phloem. Decreases in immunodetected nonesterified and methyl-esterified pectins were associated with extensive plant tissue degradation after root colonization by the pathogenic fungus. 相似文献
20.
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