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1.
Tubakia dryina, the causal agent of red oak (Quercus rubra) leaf spot, produced the phytotoxins isosclerone, 3-hydroxyisosclerone, 6-hydroxyisosclerone and 6-hydroxymellein in liquid culture. All toxins caused large necrosis when placed on leaves of red oak. Necrosis was also caused on white oak and eight different weed species. All toxins were non-specific phytotoxins. 相似文献
2.
Two naphthazarin phytotoxins (dihydrofusarubin and isomarticin) produced byFusarium solani were used to determine their effects on the cytology of leaves of rough lemon (Citrus jambhiri Lush) seedlings maintained in a dilute solution of the toxins. Dihydrofusarubin alone or in combination with isomarticin (80:20, v/v) caused cell necrosis above the midveins and lateral veins, plasmolysis or collapse of spongy mesophyll cells, collapse of phloem, depletion of starch, swelling of chloroplasts and disruption of cellular organization. At the ultrastructural level, the toxins affected chloroplast membranes by causing swelling, breaks in outer membranes, granal stack disorganization and swelling of intergranal membranes. The interstromal lamellae appeared as vesicles and sometimes as peripheral reticulum, with an increase in plastoglobuli. The tonoplast was broken or vesiculated. The only membranes not affected by the toxins were those of the nucleus and the mitochondria. This study establishes that the initial toxin effects of these fungal phytotoxins are on organellar membranes, primarily those of the chloroplasts, plasmalemma and tonoplast.Florida Agricultural Experiment Station Journal Series No. R-00648. This paper reports the results of research only. Mention of a trademark, warranty, proprietary product, or vendor does not constitute a guarantee by the US Department of Agriculture and does not imply its approval to the exclusion of other products or vendors that may also be suitable. 相似文献
3.
Insect pest management in wild blueberry (Vaccinium angustifolium Aiton) usually involves insecticidal sprays, which may have detrimental effects on non‐target beneficial insects. Dogbane beetle (Chrysochus auratus Fabricius) (Coleoptera: Chrysomelidae) feeds almost exclusively on spreading dogbane (Apocynum androsaemifolium L.), an increasing weed problem in wild blueberry production. Because C. auratus is an important natural enemy of spreading dogbane, we assessed its susceptibility to several insecticides it may be exposed to during insect pest management. In laboratory bioassays, we found adult dogbane beetles were highly susceptible to field rates of phosmet (Imidan) and acetamiprid (Assail) by direct topical contact and ingestion of treated foliage, whereas no mortality was seen with spirotetramat (Movento) and chlorantraniliprole (Altacor). Topical applications of spinetoram (Delegate) did not cause significant mortality of beetles, but high mortality to beetles was found when they ingested spinetoram‐treated foliage. The results suggest that while some insecticides used in blueberry management will be hazardous to C. auratus, options are available that will cause little harm to this natural enemy. 相似文献
4.
Cong Hou Kang Ning Xiuye Wei Yufei Cheng Huatao Yu Haibin Yu Xia Liu Linlin Dong 《Phyton》2023,92(7):2087-2103
Abscisic acid (ABA) is involved in regulating diverse biological processes, but its signal transduction genes and roles in hemp seed germination are not well known. Here, the ABA signaling pathway members, PYL, PP2C and SnRK2 gene families, were identified from the hemp reference genome, including 7 CsPYL (pyrab-actin resistance1-like, ABA receptor), 8 CsPP2CA (group A protein phosphatase 2c), and 7 CsSnRK2 (sucrose nonfermenting1-related protein kinase 2). The content of ABA in hemp seeds in germination stage is lower than that in non-germination stage. Exogenous ABA (1 or 10 μM) treatment had a significant regulatory effect on the selected PYL, PP2C, SnRK2 gene families. CsAHG3 and CsHAI1 were most significantly affected by exogenous ABA treatment. Yeast two-hybrid experiments were performed to reveal that CsPYL5, CsSnRK2.2, and CsSnRK2.3 could interact with CsPP2CA7 and demonstrate that this interaction was ABA-independent. Our results indicated that CsPYL5, CsSnRK2.2, CsSnRK2.3 and CsPP2CA7 might involve in the ABA signaling transduction pathway of hemp seeds during the hemp seed germination stages. This study suggested that novel genetic views can be brought into investigation of ABA signaling pathway in hemp seeds and lay the foundation for further exploration of the mechanism of hemp seed germination. 相似文献
5.
Xiao‐Yu Yang Jun‐Xian Zhang Qiu‐Yan Ding Zi‐Cong He Chun‐Yan Zhu Ke‐Qin Zhang Xue‐Mei Niu 《化学与生物多样性》2020,17(5)
Thermomyces lanuginosus and Scytalidium thermophilum are among the most ubiquitous thermophilic fungi in compost and soil. Chemical study on these two prevalent strains collected from Yunnan led to isolation of 23 metabolites, including one new metabolite, therlanubutanolide, and 15 known compounds, isolated from the YGP culture broth of Thermomyces lanuginosus and 7 known compounds isolated from Scytalidium thermophilum, respectively. Therlanubutanolide shared the quite similar features of the same carbon skeleton and saturation as natural hexadecanoic acids. This was the first reported discovery of such a lactone as natural occurring metabolite. All the compounds were reported for the first time from thermophilic fungi. Among them, N‐[(2S,3R,4E,8E)‐1,3‐dihydroxy‐9‐methyloctadeca‐4,8‐dien‐2‐yl]acetamide was for the first time reported to be a naturally occurring metabolite and its NMR data was first provided in this study. A type of PKS‐derived metabolites, three 3,4‐dihydronaphthalen‐1(2H)‐ones, which were widely found in plant pathogenic fungi as phytotoxins and reported to have antimicrobial activity, were obtained from both dominant thermophilic fungi. The frequent occurrence of such PKS phytotoxins in these two thermophilic fungi might suggest particular ecological interest. 相似文献
6.
R. J. Bino J. Franken H. M. A. Witsenboer J. Hille J. J. M. Dons 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(2):204-208
Summary Effects of the phytotoxic compounds (AAL-toxins) isolated from cell-free culture filtrates of Alternaria alternata f.sp. lycopersici on in vitro pollen development were studied. AAL-toxins inhibited both germination and tube growth of pollen from several Lycopersicon genotypes. Pollen from susceptible genotypes, however, was more sensitive for AAL-toxins than pollen from resistant plants, while pollen of species not belonging to the host range of the fungus was not significantly affected by the tested toxin concentrations. AAL-toxins elicit symptoms in detached leaf bioassays indistinguishable from those observed on leaves of fungal infected tomato plants, and toxins play a major role in the pathogenesis. Apparently, pathogenesis-related processes and mechanisms involved in disease resistance are expressed in both vegetative and generative tissues. This overlap in gene expression between the sporophytic and gametophytic level of a plant may be advantageously utilized in plant breeding programmes. Pollen may be used to distinguish susceptible and resistant plants and to select for resistances and tolerances against phytotoxins and other selective agents. 相似文献
7.
Production of the Streptomyces scabies coronafacoyl phytotoxins involves a novel biosynthetic pathway with an F420‐dependent oxidoreductase and a short‐chain dehydrogenase/reductase
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Luke Bown Mead S. Altowairish Joanna K. Fyans Dawn R. D. Bignell 《Molecular microbiology》2016,101(1):122-135
Coronafacoyl phytotoxins are secondary metabolites that are produced by various phytopathogenic bacteria, including several pathovars of the Gram‐negative bacterium Pseudomonas syringae as well as the Gram‐positive potato scab pathogen Streptomyces scabies. The phytotoxins are composed of the polyketide coronafacic acid (CFA) linked via an amide bond to amino acids or amino acid derivatives, and their biosynthesis involves the cfa and cfa‐like gene clusters that are found in P. syringae and S. scabies, respectively. The S. scabies cfa‐like gene cluster was previously reported to contain several genes that are absent from the P. syringae cfa gene cluster, including one (oxr) encoding a putative F420—dependent oxidoreductase, and another (sdr) encoding a predicted short‐chain dehydrogenase/reductase. Using gene deletion analysis, we demonstrated that both oxr and sdr are required for normal production of the S. scabies coronafacoyl phytotoxins, and structural analysis of metabolites that accumulated in the Δsdr mutant cultures revealed that Sdr is directly involved in the biosynthesis of the CFA moiety. Our results suggest that S. scabies and P. syringae use distinct biosynthetic pathways for producing coronafacoyl phytotoxins, which are important mediators of host‐pathogen interactions in various plant pathosystems. 相似文献
8.
Megan C. MacEachern-Balodis Nathan S. Boyd Scott N. White G. Christopher Cutler 《Arthropod-Plant Interactions》2017,11(6):807-814
We carried out experiments that considered the feeding, phenology, and biocontrol potential of dogbane beetle, Chrysochus auratus, on spreading dogbane, Apocynum androsaemifolium, a native perennial weed in lowbush blueberry (Vaccinium angustifolium). In no-choice host-feeding experiments, adult beetles did not feed upon common milkweed (Asclepias syriaca), periwinkle (Vinca minor), wild raisin (Viburnum cassenoides), and lowbush blueberry, all plants related to spreading dogbane or found around lowbush blueberry fields. In a field experiment, significant decreases in spreading dogbane total and foliar weight occurred at a density of 16 beetles per ramet, but not at lower beetle densities. In our Nova Scotia (NS) field sites, beetles were present for 8–12 weeks, beginning in late June or early July (225–335 growing degree days, GDD). Beetle abundance peaked at 4–7 beetles/m2 and occurred at 357–577 GDD, which temporally coincides with the incidence of mature spreading dogbane plants in the field. The results suggest that although inundations of C. auratus could cause significant defoliation of spreading dogbane, natural populations of the beetle probably could not satisfactorily suppress development of this weed as a stand-alone control tactic. Conservation and augmentation of C. auratus populations should nonetheless be encouraged in integrated management programs for spreading dogbane. 相似文献
9.
A. G. Valladares Juárez J. Dreyer P. K. Göpel N. Koschke D. Frank H. Märkl R. Müller 《Applied microbiology and biotechnology》2009,83(3):521-527
Novel thermophilic and alkaliphilic bacteria for the processing of bast fibres were isolated using hemp pectin as substrate.
The strain PB94A, which showed the highest growth rate (μ = 0.5/h) was identified as Geobacillus thermoglucosidasius (DSM 21625). The strain grew optimally at 60°C and pH 8.5. During growth on citrus pectin, the strain produced pectinolytic
lyases, which were excreted into the medium. In contrast to the commercially available pectinase Bioprep 3000 L, the enzymes
from G. thermoglucosidasius PB94A converted pectin isolated from hemp fibres. In addition to hemp pectin, the culture supernatant also degraded citrus,
sugar beet and apple pectin and polygalacturonic acid. When hemp fibres were incubated with the cell-free fermentation broth
of G. thermoglucosidasius PB94A, the fineness of the fibres increased. The strain did not produce any cellulases, which is important in order to avoid
damaging the fibres during incubation. Therefore, these bacteria or their enzymes can be used to produce fine high-quality
hemp fibres. 相似文献
10.
G. Janardana Rao G. Govindaraju Niranjali Sivasithamparam E. R. B. Shanmugasundaram 《Plant and Soil》1982,66(1):121-123
The mycotoxins citrinin, patulin and terreic acid are absorbed by rice seedling roots and translocated to shoots. Ten day analysis of toxin treated plants showed persistence of citrinin, patulin and terreic acid. All three toxins at a concentration of 100 ppm showed phytotoxic activity indicating terreic acid in addition to citrinin and patulin as phytotoxins. 相似文献
11.
Phytotoxins are secondary microbial metabolites that play an essential role in the development of disease symptoms induced by fungi on host plants. Although phytotoxins can cause extensive—and in some cases devastating—damage to agricultural crops, they can also represent an important tool to develop natural herbicides when produced by fungi and plants to inhibit the growth and spread of weeds. An alternative strategy to biologically control parasitic plants is based on the use of plant and fungal metabolites, which stimulate seed germination in the absence of the host plant. Nontoxigenic fungi also produce bioactive metabolites with potential fungicide and insecticide activity, and could be applied for crop protection. All these metabolites represent important tools to develop eco‐friendly pesticides. This review deals with the relationships between the biological activity of some phytotoxins, seed germination stimulants, fungicides and insecticides, and their stereochemistry. Chirality 25:59–78, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
12.
The production of energy crops that can be used for biodiesel production is a sustainable approach for the removal of metal pollutants by phytoremediation. This study investigated the cadmium (Cd) accumulation and tolerance of eight potential energy crops. After growth for 28 days in substrates containing 0, 50, 100 or 200 mg Cd·kg− 1, seedlings were evaluated for growth parameters, chlorophyll content, chlorophyll fluorescence parameters and Cd accumulation. All eight crops were moderately tolerant to Cd toxicity, with four [i.e., hemp (Cannabis sativa), flax (Linum usitatissimum), castor (Ricinus communis) and peanut (Arachis hypogaea)] being more tolerant than the others. Three of these crops (hemp, flax and peanut) had higher Cd accumulation capacities. The roots of peanut and hemp had high bioconcentration factors (BCF > 1000), while flax shoots accumulated a higher concentration of Cd (> 100 mg/kg). These results demonstrate that it is possible to grow energy crops on Cd-contaminated soil. Hemp, flax and peanut are excellent candidates for phytoremediation. 相似文献
13.
Extracts from spreading chocolate spot lesions contained a heat-stable,water-soluble, ether- or ethanol-insoluble phytotoxic fraction.Elution from Sephadex G75 indicated that the molecular weightsof the toxic compounds were between 10000 and 30000 daltons.The toxins were adsorbed on DEAE Sephadex and eluted from itwith 0.10.2 M NaCl. Toxic activity was enhanced in solutionswith low osmotic potentials similar to those found in lesions.Controlling the growth of contaminating bacteria in lesionswith antibiotics appeared to reduce the levels of heat-stabletoxins extracted and to reduce the rate of increase in lesionsize. There were high levels of polygalacturonase (PG) activity inlesion extracts; large quantitites of PG, but little or no trans-eliminases,were produced by Botrytis fabae in liquid culture. A pectolyticstrain of Bacillus lentus was associated with trans-eliminasesin lesion extracts, and produced transeliminases, but not PG,in liquid culture. Activities of both heat-stable phytotoxins and of pectic enzymesmay depend on fungal isolate and types and populations of contaminatingbacteria. Botrytis fabae L., Bacillus, Vicia faba L., phytotoxins, pectic enzymes, chocolate spot 相似文献
14.
Anna Maria Mercuri Carla Alberta Accorsi Marta Bandini Mazzanti 《Vegetation History and Archaeobotany》2002,11(4):263-276
The cores from the Albano and Nemi lakes, near Rome, were studied within the European Union funded PALICLAS project and provided
high resolution records of the Late-glacial and Holocene. Pollen evidence of increasing human influence on vegetation was
recorded in the Holocene parts of both diagrams, and the Cannabis (hemp) curve was one of the major signs. In this paper we present unambiguous pollen evidence from the Cannabaceae records
for the cultivation of hemp in central Italy by the Romans. The oldest records of Cannabis and Humulus (hop) date from to the Late-glacial. Hop pollen values rise during the mid Holocene, while hemp pollen becomes more abundant
from ca. 3000 cal B.P. onwards. The highest earliest hemp peak (21%) is dated to the 1st century A.D. This ‘Cannabis phase’, with the abrupt rise of hemp pollen soon after the rise of cultivated trees (Castanea, Juglans and Olea) is associated with the increase in cereals and ruderal plants. This unambiguous proof of cultivation by Romans around 2000
B.P. occurs as well as a long lasting pre-Roman presence of hemp in the area, which is natural and possibly also anthropogenic.
Subsequent clear episodes of cultivation in the medieval period were found.
Received February 4, 2002 / Accepted September 13, 2002
Correspondence to: Anna Maria Mercuri, e-mail: mercuri.annamaria@unimo.it 相似文献
15.
M. A. K. Lodhi 《American journal of botany》1978,65(3):340-344
Phytotoxins released by the dominant species in a lowland forest showed highest accumulations in their respective stands. The accumulation of such phytotoxins corresponded with the amount of litter produced and its decaying rate. The release of phytotoxins and their activity depended on whether they were free or bound, and on their solubility. Therefore, the phytotoxins in soils were highly variable in amounts from one species stand to another species stand, during the same and different times of the year. The persistent accumulation of phytotoxins from all dominant tree species continues to influence the soil properties around the trees. Fourteen phytotoxins were isolated from the leaf litter and the soil. Seven persistent toxins were quantified in soils under different tree stands at various times of the year. The cycle of release of bound and free phenolics is discussed. 相似文献
16.
The activity of some phytotoxic metabolites of Pseudomonas syringae pv. syringae Van Hall strains B359 and B301 on in vivo and in vitro systems of H+-transport across the plasma membrane of maize (Zea mays L., hybrid Paolo) was investigated. In particular syringomycin, the first lipodepsinonapeptide isolated from Pss and already studied in plants and yeasts for its effects on several physiological systems, was compared with the recently described lipodepsipeptides with 22 or 25 amino acid residues, so called syringopeptins. The in vivo activity of the phytotoxins was tested on fusicoccin-stimulated H?-extrusion from cuttings of maize roots, which was inhibited by both types of toxins, with syringomycin more efficient than the syringopeptins. In vitro the H+-ATPase activity of predominantly right-side-out plasma membrane vesicles purified by two-phase partitioning was stimulated by 10 μM syringomycin and inhibited by higher levels, in agreement with the results of others with preparations of dicotyledons. Also the inhibition of the phosphohydrolytic activity of inside-out vesicles of mung bean plasma membrane was confirmed for maize. In both types of vesicles the syringopeptirts were better inhibitors than syringomycin. The pH gradient formed on addition of ATP to predominantly (25% latency) inside-out vesicles was immediately and completely collapsed by syringomycin and syringopeptins; H+-pumping was prevented if the toxins were added before ATP. The inhibition was concentration dependent, but at very low concentrations the effect was inverted. The results of the present investigation, carried out with maize preparations, confirm and extend the evidence so far obtained with dicotyledons in favour of the plasma membrane as an important site of interaction of syringomycin with the plant cell. They also indicate that, except for some details, the effects of syringopeptins at the level of the plasma membrane are the same as those of syringomycin. 相似文献
17.
【背景】麻类生物脱胶与化学法脱胶相比具有环保优势。【目的】获得用于汉麻生物脱胶的高效果胶酶菌株。【方法】使用以果胶为唯一碳源的培养基,采用平板稀释法进行菌株筛选,通过生理生化实验和16s rRNA基因序列比对鉴定目标菌株。采用单因素试验优化产酶条件,并验证该条件下汉麻生物脱胶效果。【结果】获得一株具备高活性果胶的酶菌株,归类为果胶杆菌(Pectobacterium aroidearum) WNH。在培养温度27 °C、转速160 r/min、接种量10%、初始pH 7.0的条件下培养16 h后,果胶杆菌WNH的粗酶液果胶酶活力达155.03 U/mL。按上述条件对汉麻韧皮进行二次脱胶处理,处理后脱胶率为27.18%,较对照组提高了6.93%。【结论】果胶杆菌WNH具备汉麻生物脱胶的潜力。 相似文献
18.
The potential of hemp (Cannabis sativa L.) for sustainable fibre production: a crop physiological appraisal 总被引:1,自引:0,他引:1
Hemp (Cannabis sativa L.) fibre can be used as a raw material for paper and textile production. A comprehensive research programme in the Netherlands has concluded that fibre hemp is a potentially profitable crop, having the right profile to fit into sustainable farming systems. This paper presents an appraisal of the crop physiological characteristics and the agronomic potential of hemp. Parameter values of basic crop physiological characteristics such as light interception potential, radiation use efficiency and dry matter partitioning coefficients are given. The effect of crop management decisions such as cultivar choice, sowing date, plant density, and harvest date on the value of these parameters is discussed. A simple crop growth model was used to assess the yield potential of hemp for the climate of the Netherlands. Calculations made for a non-stressed late-flowering hemp crop sown on 15 April and harvested on 15 September give a stem dry matter yield of 17.1 t ha-1. The effects of advancing or delaying sowing or harvest date on stem yield were calculated. Crop physiological characteristics of hemp are compared to those of kenaf (Hibiscus cannabinus L.). Radiation use efficiency and dry matter partitioning coefficients of the two crops are similar. Base temperatures for development and growth are lower in hemp than in kenaf. In a temperate climate with cool springs, canopy establishment will be more rapid in hemp than in kenaf. Hemp seems an excellent candidate to fill the niche for an annual fibre crop in a temperate climate. 相似文献
19.
James Chitamba Pepukai Manjeru Cleopas C. Chinheya 《Archives Of Phytopathology And Plant Protection》2013,46(6):761-773
Radopholus similis is the most destructive plant parasitic nematode in banana production systems. A glasshouse experiment was carried out to evaluate the effect of legume intercrops on R. similis population and damage level in banana. A trial was laid out in a randomised complete block design with five treatments and five replications. The treatments were banana/cowpea (Vigna unguiculata) intercrop, banana/sunn hemp (Crotalaria juncea) intercrop, sole banana, sole banana with nematicide (Fenamiphos) and sole cowpea. Sunn hemp intercrop was suppressing R. similis population densities and reduced banana root damage the most compared to tested treatments. The legume intercropped banana plants had a significantly higher fresh root mass as the sole-cropped banana with nematicide while the sole-cropped banana without nematicide had significantly lowest fresh root mass. Sunn hemp and cowpea legumes are recommended for adoption by smallholder banana farmers as alternatives to nematicide use. 相似文献
20.
Phialophora parasitica, Causal Agent of Cherry Dieback 总被引:1,自引:0,他引:1
I. C. Rumbos 《Journal of Phytopathology》1986,117(3):283-287
Structure-activity relationships of the phytotoxins stemphyloxin I and II from Stemphylium botryosum f. sp. lycopersici were investigated by quantitative comparison of their biological activity with chemically related phytotoxins from Phoma betae, betaenones A, B and C. Phytotoxicity was estimated by inhibition of incorporation of14C-leucine into proteins of exponentially growing tomato cells. The values of 50 % inhibition for stemphyloxin I and II and for betaenones A, B and C were 0.075, 16, 55, 350 and 1 μM respectively. The β-ketoaldehyde moiety appeared to be essential in, conferring biological activity and its toxicity was influenced by its spatial orientation. The presence of an hydroxyl group in stemphyloxin I and II enhanced activity in comparison with the respective compounds betaenones C and A which lack this group. 相似文献