共查询到20条相似文献,搜索用时 31 毫秒
1.
A leaf beetle, Crioceris sp. (Coleoptera: Chrysomelidae), was introduced into Australia as a biological control agent of bridal creeper (Asparagus asparagoides L. Druce) during October 2002. Rearing of Crioceris sp. is labour intensive therefore all releases of Crioceris sp. have been under 1000 individuals, which may be too low to ensure establishment if high mortality and high competition
with other agents occurs. The aim of this study is to understand how the presence of two well-established biocontrol agents,
a rust fungus (Puccinia myrsiphylli (Thuem) Wint [Basidiomycota: Uredinales]) and a leafhopper (Zygina sp. [Hemiptera: Cicadellidae]), might influence Crioceris sp. establishment. Crioceris sp. neonate larvae were placed on bridal creeper plants with or without the leafhopper and/or rust. The number of larvae
that pupated was reduced by 38 and 65% in the presence of the rust fungus and leafhopper, respectively and by 45% in the presence
of both agents. As the area infected by the rust increased the area damaged by the leafhopper decreased. The rust appeared
to be negatively impacted by the presence of the leafhopper. In a second experiment, female Crioceris sp. adults were given a choice between uninfested bridal creeper plants and those infested with the rust or the leafhopper.
The females preferred to lay their eggs on plants without leafhoppers but did not seem to be deterred by the presence of the
rust. Consequently, the performance and impact of Crioceris sp. on bridal creeper may be reduced if populations overlap with the other biocontrol agents in the field. 相似文献
2.
Interactions between invasive species can have important consequences for the speed and impact of biological invasions. Containers
occupied by the invasive mosquito, Aedes albopictus Skuse, may be sensitive to invasive plants whose leaves fall into this larval habitat. To examine the potential for interactions
between invasive leaf species and larval A. albopictus, we conducted a field survey of leaf material found with A. albopictus in containers in Palm Beach County, Florida and measured density dependent responses of A. albopictus larvae to two invasive and one native leaf species in laboratory experiments. We found increased diversity of leaf species,
particularly invasive species, in areas further from the urbanized coast, and a significant positive association between the
presence of Schinus terebinthifolious (Brazilian pepper) and the abundance of A. albopictus. In laboratory experiments, we determined that larval growth and survivorship were significantly affected by both larval
density and leaf species which, in turn, resulted in higher population performance on the most abundant invasive species (Brazilian
pepper) relative to the most abundant native species, Quercus virginiana (live oak). These results suggest invasive leaf species can alleviate density dependent reductions in population performance
in A. albopictus, and may contribute to its invasion success and potential to spread infectious disease. 相似文献
3.
Yan Bao Lei Yu Long Feng Yu Long Zheng Rui Fang Wang He De Gong Yi Ping Zhang 《Biological invasions》2011,13(12):2703-2714
Both innate and evolutionarily increased ecophysiological advantages can contribute to vigorous growth, and eventually to
invasiveness of alien plants. Little effort has been made to explore the roles of innate factors of alien plants in invasiveness
and the effects of CO2 enrichment on alien plant invasions. To address these problems, we compared invasive Eupatorium adenophorum, its native conspecific, and a native congener (E. japonicum) under ambient and doubled atmospheric CO2 concentrations. Native E. adenophorum from Mexico grew slower than invasive E. adenophorum but faster than native E. japonicum under both CO2 concentrations. The faster growth rate of invasive E. adenophorum was associated with higher photosynthetic capacity and leaf area ratio. For invasive E. adenophorum, the higher photosynthetic capacity was associated with higher nitrogen (N) allocation to photosynthesis, which was related
to lower leaf mass per area; the higher leaf area ratio was due to lower leaf mass per area and higher leaf mass fraction.
Tradeoff between N allocations to photosynthesis versus defenses was found. CO2 enrichment significantly increased relative growth rate and biomass accumulation by increasing actual photosynthetic rate
for all studied materials. However, the relative increase in growth was not significantly different among them. CO2 enrichment did not influence N allocation to photosynthesis, but increased N allocation to cell walls. The reduced leaf N
content decreased N content in photosynthesis, explaining the down-regulation of photosynthetic capacity under prolonged elevated
CO2 concentration. Our results indicate that both innate and evolutionary advantages in growth and related ecophysiological traits
contribute to invasiveness of invasive E. adenophorum, and CO2 enrichment may not aggravate E. adenophroum’s invasion in the future. 相似文献
4.
Helen T. Murphy B. D. Hardesty C. S. Fletcher D. J. Metcalfe D. A. Westcott S. J. Brooks 《Biological invasions》2008,10(6):925-936
Miconia calvescens (Melastomataceae) is a serious invader in the tropical Pacific, including the Hawaiian and Tahitian Islands, and currently
poses a major threat to native biodiversity in the Wet Tropics of Australia. The species is fleshy-fruited, small-seeded and
shade tolerant, and thus has the potential to be dispersed widely and recruit in relatively intact rainforest habitats, displacing
native species. Understanding and predicting the rate of spread is critical for the design and implementation of effective
management actions. We used an individual-based model incorporating a dispersal function derived from dispersal curves for
similar berry-fruited native species, and life-history parameters of fecundity and mortality to predict the spatial structure
of a Miconia population after a 30 year time period. We compared the modelled population spatial structure to that of an actual infestation
in the rainforests of north Queensland. Our goal was to assess how well the model predicts actual dispersion and to identify
potential barriers and conduits to seed movement and seedling establishment. The model overpredicts overall population size
and the spatial extent of the actual infestation, predicting individuals to occur at a maximum 1,750 m from the source compared
with the maximum distance of any detected individual in the actual infestation of 1,191 m. We identify several characteristic
features of managed invasive populations that make comparisons between modelled outcomes and actual infestations difficult.
Our results suggest that the model’s ability to predict both spatial structure and spread of the population will be improved
by incorporating a spatially explicit element, with dispersal and recruitment probabilities that reflect the relative suitability
of different parts of the landscape for these processes. 相似文献
5.
To better understand the requirement of light and soil water conditions in the invasion sites of two invasive weeds, Mikania micrantha and Chromolaena odorata, we investigated their structural and physiological traits in response to nine combined treatments of light [full, medium
and low irradiance (LI)] and soil water (full, medium and low field water content) conditions in three glasshouses. Under
the same light conditions, most variables for both species did not vary significantly among different water treatments. Irrespective
of water treatment, both species showed significant decreases in maximum light saturated photosynthetic rate (P
max), photosynthetic nitrogen-use efficiency, and relative growth rate under LI relative to full irradiance; specific leaf area,
however, increased significantly from full to LI though leaf area decreased significantly, indicating that limited light availability
under extreme shade was the critical factor restricting the growth of both species. Our results also indicated that M. micrantha performed best under a high light and full soil water combination, while C. odorata was more efficient in growth under a high light and medium soil water combination. 相似文献
6.
Mario C. N. Saparrat Geraldine E. Fermoselle Sebastián A. Stenglein Mónica B. Aulicino Pedro A. Balatti 《Mycopathologia》2009,168(1):41-47
Pseudocercospora griseola is the causal agent of angular leaf spot of common bean (ALS). It has undergone parallel coevolution with its host and two
major groups have been defined, “Andean” (P. griseola f. griseola) and “Mesoamerican” (P. griseola f. mesoamericana). The aim of this study was to analyze the nature and the level of the dark pigment synthesized by the representatives of
each group. After 21 days of incubation on potato dextrose agar medium, P. griseola f. griseola isolate S3b developed colonies with diameters of 17.5 ± 1.3 mm and concentric rings of pigmentation. Isolate T4 of P. griseola f. mesoamericana presented smaller colonies (9.9 ± 0.3 mm) with a uniform dark-gray color. Both isolates, S3b and T4, produced the same pigment,
a 1,8-dihydroxynaphthalene-melanin, although different in quantity and structural features as suggested by the IR spectrum.
The P. griseola f. griseola isolate S3b had a higher growth rate and melanin content as well as smaller sensitivity to melanin synthesis inhibitors compared
to the isolate T4 of P. griseola f. mesoamericana. These results suggest a possible link between melanin and growth in P. griseola. 相似文献
7.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
8.
Daisuke Kurose Harry C. Evans Djamila H. Djeddour Paul F. Cannon Naruto Furuya Kenichi Tsuchiya 《Mycoscience》2009,50(3):179-189
Native to Japan, Fallopia japonica, most frequently referred to as Japanese knotweed, is a highly problematic invasive weed, particularly in the UK and North
America. During surveys for natural enemies of this plant in Japan, two species of Mycosphaerella were collected. One of these was identified as M. polygoni-cuspidati, and is redescribed and neotypified. Causing a damaging leaf spot disease of F. japonica throughout its natural range in Japan, it is absent from the host’s exotic range. The restriction of M. polygoni-cuspidati to F. japonica in its center of origin, together with its severe impact on host fitness, indicates that this is a coevolved natural enemy
with high potential as a classical biological control agent for the long-term management of this ecologically and economically
important weed. In the field, the fungus has a reduced life cycle, with only spermogonia and pseudothecia (ascomata) being
formed. Ascospores are the primary source of infection, and studies show that the mycelium from in vitro cultures is also
infective and hyphae penetrate mainly via the stomata. A further, undescribed species of Mycosphaerella co-occurs with M. polygoni-cuspidati, here proposed as the new species M. shimabarensis. Both species have been studied using cultural, morphological and molecular phylogenetic methods. 相似文献
9.
X. Liu J. Jia S. Atkinson M. Cámara K. Gao H. Li J. Cao 《World journal of microbiology & biotechnology》2010,26(8):1465-1471
Biological control is being considered as an alternative or a supplemental way of reducing the use of chemicals in agriculture.
An endophytic strain G3 with potential as a biocontrol agent was isolated from the stems of Triticum aestivum L. It was classified by 16S rDNA sequencing as a member of Serratia. Strain G3 displayed a broad spectrum of antifungal activity in vitro against a number of phytopathogens such as Botrytis cinerea, Cryphonectria parasitica, Rhizoctonia cerealis and Valsa sordida. Molecular mechanisms involved in biocontrol by Serratia sp. G3 was investigated for its potential application to plant health management. The results showed that G3 produces an
array of antimicrobial exoproducts, including chitinase, protease, antibiotic pyrrolnitrin, and siderophores for iron competition.
Moreover, it also produced the plant growth hormone indole-3-acetic acid, suggesting that multiple mechanisms and their synergistic
effects may be involved in biocontrol of plant diseases. Additionally, strain G3 can produce at least ten N-acyl homoserine lactones (AHLs) signal molecules for cell to cell communication, including unsubstituted, 3-oxo, and 3-hydroxy
at the C3 position through liquid chromatography-tandem mass spectrometry (LC-MS/MS), which is different from the previously
reported Serraia species. For the first time, N-3-oxo-heptanoyl-homoserine lactone, one of the main molecules was reported in the genus Serratia. The role of AHL-dependent quorum sensing system in the interactions between the endophytic strain G3 and host plants and
its potential application in improving biocontrol efficacy will be further explored. 相似文献
10.
Tainya C. Clarke Kateel G. Shetty Krishnaswamy Jayachandran Michael R. Norland 《BioControl》2007,52(3):399-411
One of the greatest threats to the native ecosystems in any part of the world is the invasion and permanent colonization of
ecosystems by non-native species. Florida is no exception to this biological invasion, and is currently colonized by an extensive
variety of exotic plant species. Originally imported from Asia over 30 years ago, Old World Climbing Fern Lygodium microphyllum (Cavanilles) R. Brown) has become one of the most invasive and destructive weeds in southern Florida. To date different effective
control measures of its growth and spread have not been successful; fire and herbicide applications that are currently employed
are neither cost effective nor environmentally friendly. In light of the highly delicate ecosystem that is being affected
by L. microphyllum, we tested the soil fungus Myrothecium verrucaria (Albertini and Schwein) Ditmar: Fr. for its pathogenicity on the invasive fern. In greenhouse studies the effect of two conidial
concentrations of M. verrucaria on L. microphyllum was investigated. Plants were spray inoculated with M. verrucaria which resulted in successful disease development with leaf necrosis symptoms. The higher conidial concentration (1 × 108 ml−1) produced a disease index of approximately 3 on a scale of 0 to 4, day 24 postinitial inoculation, demonstrating the efficacy
of this fungus as a severe retardant of Lygodium growth. Preliminary screening of selected native plant species for susceptibility to M. verrucaria showed low disease indices after repeated spray inoculations; the highest index attained was 0.4 by Slash pine (Pinus elliottii). 相似文献
11.
Photosynthetic rate (P
N), SPAD value, specific leaf area (SLA), flag leaf area (FLA), and nitrogen content (LN) of genus Oryza were investigated and their correlation was analyzed to assess some of the main photosynthetic traits among different species
in the genus Oryza. The results revealed wide variation in these traits. The species O. rufipogon and O. australiensis exhibited maximum photosynthetic rate. Comparison of different types of genomes (diploid: 2n=2x=24; tetraploid: 2n=4x=48)
and growth habit (shade- or sun-grown) showed the species of diploid (with genome symbol EE; 2n=2x=24) genomes, with perennial
and sun-grown species, had high apparent photosynthesis compared to others. The species with BB/BBCC, shade-grown and the
tetraploids showed high SPAD value, and the flag leaf in sun-grown species and diploids were thicker (low SLA) compared with
others. However, no significant difference could be noticed among the different types of genomes. Higher leaf area was noticed
among the species of CC/CCDD genome, perennial shade-grown species and tetraploids than in others. The variety IR 36 exhibited
highest leaf nitrogen concentration. Correlation analysis showed a strong relationship between P
N and leaf nitrogen concentration while no marked relationships were observed among other characteristics. It implies that
the species with thick and small leaves with high nitrogen concentration and high photosynthesis evolved better than others.
O. rufipogon, with the same genome as O. sativa, could be one of the wild rice resources for elite crop improvement. 相似文献
12.
S. Kumar Sunil Kumar S. P. Negi J. K. Kanwar 《In vitro cellular & developmental biology. Plant》2008,44(6):474-479
Callus cultures derived from leaf segments of chrysanthemum cultivar ‘Snow Ball’ which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium
containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About
30% of the plants regenerated from the resistant calluses and 70–80% of the plants raised from cuttings had acquired considerable
resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates. 相似文献
13.
Kottackal Poulose Martin A. K. Pradeep Joseph Madassery 《Acta Physiologiae Plantarum》2011,33(4):1141-1148
Trichopus zeylanicus subsp. travancoricus (known as Arogyapacha), an endangered ethnomedicinal plant of the Western Ghats of South India, serves as the major source
of the commercial drug Jeevani. The present study established a long-term high frequency in vitro propagation protocol for Arogyapacha. Callus obtained from
the branch–petiole explants cultured on Murashige and Skoog (MS) medium with 4.5 μM 2,4-dichlorophenoxyacetic acid upon subculture
to medium with different concentrations of 6-benzyladenine (BA) either alone or in combination with an auxin favoured shoot
morphogenesis. Medium with 13.3 μM BA alone facilitated high frequency shoot bud (mean of 93.2) formation. Medium with lower
concentrations of BA (4.4, 6.6 and 8.8 μM) alone or in combination with lower concentration of α-naphthaleneacetic acid (NAA)
or indole-3-butyric acid (IBA) favoured better shoot growth than 13.3 μM BA containing medium, but with reduced number of
shoot buds. Subsequent cultures on medium with lower concentrations of BA and also on MS basal media facilitated shoot formation
as well as growth of shoots. The shoot regeneration potential showed no decline up to 5 years. Culture of the in vitro-derived
whole branch–leaf explants on MS basal medium developed shoots directly from the node. On medium with 19.6 μM IBA, the whole
branch–leaf explants induced nodular callus from the node, which developed shoots later. Subsequent cultures on medium with
BA exhibited high frequency shoot formation. The transfer of shoots after 10–15 days culture on half-strength MS medium containing
2.7 μM NAA to half-strength basal medium induced a mean of 11.3 roots. Field survival of plantlets relied on the soil mix:
a 1:4 ratio of sand and red-soil exhibited the highest plantlets survival (86.6%). RAPD profile of the source plant and plants
regenerated from calli after 4 years showed no polymorphism. The established plantlets with morpho-floral features similar
to that of the source plants flowered normally and set fruits. 相似文献
14.
Nanobodies (or VHHs) are single-domain antigen-binding fragments derived from Camelid heavy chain-only antibodies. Their small size, monomeric behaviour, high stability and solubility, and ability to bind epitopes
not accessible to conventional antibodies make them especially suitable for many therapeutic and biotechnological applications.
Here we describe high-level expression, in Nicotiana benthamiana, of three versions of an anti-hen egg white lysozyme (HEWL) nanobody which include the original VHH from an immunized library
(cAbLys3), a codon-optimized derivative, and a codon-optimized hybrid nanobody comprising the CDRs of cAbLys3 grafted onto
an alternative ‘universal’ nanobody framework. His6- and StrepII-tagged derivatives of each nanobody were targeted for accumulation
in the cytoplasm, chloroplast and apoplast using different pre-sequences. When targeted to the apoplast, intact functional
nanobodies accumulated at an exceptionally high level (up to 30% total leaf protein), demonstrating the great potential of
plants as a nanobody production system. 相似文献
15.
Members of the genus Rhytidoponera and, to a lesser extent, certain Melophorus spp. are keystone mutualists for the dispersal of seeds in the southwest of Western Australia, with important ramifications
for the ecology and speciation of plants in this biodiversity hotspot. For this reason, it is important to understand the
autecology of the relevant ant species and the way in which they interact with plant seeds. This paper addresses key aspects
of the ecology of three such ant species, Rhytidoponera violacea (Forel), R. inornata Crawley and Melophorus turneri perthensis Wheeler. Data are presented on their geographic distribution, seasonality of foraging, diurnal activity, response to fire,
nest site preference, nest structure, colony size, feeding habits, foraging response to seed availability, and seedling emergence
from nests. The role of all three species as seed dispersers is confirmed, and all three species have ecologies that are well-suited
for dispersal and survival of native plant seeds. Preservation of this interaction is important for the conservation of plants,
and it is fortuitous that all three species are able to survive disturbance and return to rehabilitated areas. However, the
smaller R. inornata, and to a lesser extent, the larger R. violacea, are vulnerable to invasive ant [Pheidole megacephala (Fabricius)] incursions. M. turneri perthensis is able to coexist with the invasive ant unless this is at high densities, probably as a result of its ability to forage
during high temperatures when the invasive species is inactive. 相似文献
16.
Pseudomonas fluorescens strains are known to produce a wide range of secondary metabolites including phenazines, siderophores, pyoluteorin, and 2,4
diacetylphloroglucinol (DAPG). DAPG is of particular interest because of its antifungal properties and because its production
is associated with inhibition of phytopathogenic fungi in natural disease-suppressive soils. This trait has been exploited
to develop strains of P. fluorescens that have potential application as biocontrol agents. Although the biochemistry, genetics and regulation of DAPG production
have been well-studied, relatively little is known about how DAPG inhibits fungal growth and how fungi respond to DAPG. Employing
a yeast model and a combination of phenotypic assays, molecular genetics and molecular physiological probes, we established
that inhibition of fungal growth is caused by impairment of mitochondrial function. The effect of DAPG on yeast is largely
fungistatic but DAPG also induces the formation of petite cells. Expression of the multidrug export proteins Pdr5p and Snq2p
is increased by DAPG-treatment but this appears to be a secondary effect of mitochondrial damage as no role in enhancing DAPG-tolerance
was identified for either Pdr5p or Snq2p. 相似文献
17.
The predation capacity and prey preference of larvae of Chrysoperla
carnea (Stephens) (Neuroptera: Chrysopidae) on eggs or larvae of Pieris brassicae (Linnaeus) (Lepidoptera: Pieridae) in the absence and presence of cabbage aphids as an alternative prey were evaluated in
laboratory experiments at 25°C. Both instars preyed upon butterfly eggs and larvae as well as on cabbage aphids with the third
instar being the most voracious. The lacewings had a strong preference for caterpillars to butterfly eggs. In the presence
of the aphids the predation on P. brassicae eggs or larvae was either completely abandoned or reduced by about 70%, respectively, by second instar lacewings and either
reduced by about 80% or maintained, respectively, by third instar lacewings. Both instars thus had a clear preference for
aphids compared to eggs of P. brassicae. However, second instar lacewings preferred aphids to caterpillars whereas the opposite was the case for third instar lacewings.
The results indicate that 3rd instar C. carnea has a potential as biocontrol agent against P. brassicae. 相似文献
18.
Despite species in the Rubus fruticosus complex (wild blackberry) being among the most invasive plants globally in regions with large annual fluctuations in water
availability, little is known about their water relations. We compared water relations of a prominent member of the complex,
R. armeniacus (Himalayan blackberry), with species native to the Pacific Northwest of North America (PNW), R. spectabilis (salmonberry) and R. parviflorus (thimbleberry). In eight stands of each species located near Portland, Oregon, USA, we measured mid-day hydraulic resistance
(R
plant), and daily time series of stomatal conductance (g
s), leaf water potential (Ψlf), and environmental conditions at four time periods spanning the 2007 growing season. Although all species maintained Ψlf above −0.5 MPa in spring, R. armeniacus maintained less negative Ψlf (≥−1.0 MPa) than the natives in summer, a factor attributable to advantages in both its root and shoot systems. R
plant of R. armeniacus was ≤0.1 MPa mmol−1 m2 s for the duration of the study, and approximately 25–50% of R
plant for the native species in summer. R. armeniacus had higher g
s compared to the native species throughout the spring and summer, with approximately twice their rates in summer. Our R
plant and g
s results show that R. armeniacus has access to more water during PNW summers than congeneric natives, allowing it to maintain high water-use, and potentially
helping it achieve higher growth and reproductive rates. Water relations may therefore be a critical component of the competitive
and invasive success of R. armeniacus and other R. fruticosus species worldwide. 相似文献
19.
Cereal grain is a major component of food and feed in large parts of the world. The microbial flora on cereal grains may interfere
with hygiene and storage stability, palatability and bioavailability of minerals and proteins may depend on the composition
of the microbial population. Therefore, it is of primary interest to control the microbial species present on cereal grain.
Inoculation of the biocontrol yeast Pichia anomala to cereal feed grain improved feed hygiene by reduction of moulds and Enterobacteriaceae, and enhanced the nutritional value by increasing the protein content and reducing the concentration of the antinutritional
compound phytate. P. anomala strains showed a high phytase activity, for some strains also considerable extracellular phytase activity was observed. A certain maximum in biomass concentration was never exceeded indicating cell density induced growth inhibition of P. anomala. 相似文献
20.
Lisianthus [Eustoma grandiflorum (Raf.) Shinn] is a popular cut flower crop throughout the world, and the demand for this plant for cut flowers and potted
plants has been increasing worldwide. Recent advances in genetic engineering have enabled the transformation and regeneration
of plants to become a powerful tool for improvement of lisianthus. We have established a highly efficient plant regeneration
system and Agrobacterium-mediated genetic transformation of E. grandiflorum. The greatest shoot regeneration frequency and number of shoot buds per explant are observed on media supplemented with 6-Benzylaminopurine
(BAP) and α-Naphthalene acetic acid (NAA). We report an efficient plant regeneration system using leaf explants via organogenesis
with high efficiency of transgenic plants (15%) in culture of 11 weeks’ duration. Further ectopic expression of two MADS box
genes, LMADS1-M from lily (Lilium longiflorum) and OMADS1 from orchid (Oncidium Gower Ramsey), was performed in E. grandiflorum. Conversion of second whorl petals into sepal-like structures and alteration of third whorl stamen formation were observed
in the transgenic E. grandiflorum plants ectopically expressing 35S::LMADS1-M. 35S::OMADS1 transgenic E. grandiflorum plants flowered significantly earlier than non-transgenic plants. This is the first report on the ectopic expression of two
MADS box genes in E. grandiflorum using a simple and highly efficient gene transfer protocol. Our results reveal the potential for floral modification in E. grandiflorum through genetic transformation. 相似文献