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1.
The aim of this work was to assess the effects of a combined inoculum of a rhizobacterium and an arbuscular mycorrhizal (AM) fungus on plant responses to phytoplasma infection, and on phytoplasma multiplication and viability in Chrysanthemum carinatum plants infected by chrysanthemum yellows phytoplasma (CY). Combined inoculation with Glomus mosseae BEG12 and Pseudomonas putida S1Pf1Rif resulted in some resistance to phytoplasma infection (about 30%), delayed symptom expression in nonresistant plants, improved growth of the aerial part of the infected plants (+68·1%), and altered root morphology (root tip number: +49·9%; branching degree: +82·8%). Combined inoculation with the two beneficial microorganisms did not alter CY multiplication and viability. In inoculated and infected plants, phytoplasma morphology was typical of senescent cells. A more active and efficient root system in double‐inoculated plants probably mediated the effects of the two rhizospheric microorganisms in the infected plants. The practical application of rhizospheric microorganisms for mitigating phytoplasma damage, following evaluation under field conditions, represents an additional tool for the integrated management of phytoplasmosis.  相似文献   

2.
This study investigated the potential of the arbuscular mycorrhizal (AM) fungus Glomus mosseae to protect basil (Ocimum basilicum) against Fusarium oxysporum f.sp. basilici (Fob). It was hypothesised that G. mosseae could confer a bioprotective effect against Fob as a result of increases in leaf rosmarinic (RA) and caffeic acids (CA) or essential oil concentrations. Glomus mosseae conferred a bioprotective effect against Fob by reducing plant mortality to 20% compared to 33% in non‐mycorrhizal (NM) plants. This bioprotective effect was not related to improved phosphorus (P) nutrition, as AM and NM plants treated with Fob had similar shoot P concentrations (6 and 8 mg g?1 dry weight (DW), respectively). Both AM and NM plants treated with Fob had similar leaf and root RA and CA concentrations. Furthermore, phenolic (40–70 mg CA g?1 DW) or essential oil concentrations (0·1–0·6 mg g?1 DW) were not increased in plants treated with the AM fungus and Fob. Therefore, the bioprotective effect conferred by G. mosseae was not a result of increases in the phytochemicals tested in this study. However, under the AM symbiosis, basil plants treated with Fob had lower methyleugenol concentrations in their leaves (0·1 mg g?1 DW) than NM plants treated with the pathogen (0·6 mg g?1 DW).  相似文献   

3.

The use of biofertilizers on agricultural soils could act positively to improve soil fertility and crop productivity. This work was performed to assess the potential beneficial impacts of local produced phospho-compost and/or an exogenous arbuscular mycorrhizal fungus (AMF) (Rhizoglomus irregulare DAOM 197198) on lettuce agro-physiological and soil characteristics under filed conditions. Four treatments were applied: control treatment without any biofertilizer, compost, AMF, and compost?+?AMF treatments. Obtained results showed that shoot nitrogen (N) and phosphorus (P) were significantly improved in lettuce plants treated with compost supplementation and/or AMF inoculation compared to the control with a maximum increment for P in plants treated with compost (106%). As for growth traits, lettuce plants treated with compost?+?AMF recorded the highest values in terms of shoot and root dry weights and yield by 121, 54 and 127%, respectively, compared to the control plants. Considering physiological and biochemical traits, stomatal conductance, and chlorophyll fluorescence as well leaf area index and total soluble sugar and protein concentration were significantly improved in plants treated with compost and/or AMF compared to the control. In addition, soil properties, especially the soil total organic carbon, N, P, and glomalin-related soil protein content were significantly enhanced after two months of field experiment in treated soils with the applied biofertilizers alone or in combination compared to the control. Based on the main obtained results, applied biofertilizers were able to increase lettuce productivity and soil fertility under field conditions, especially the compost?+?AMF treatment, which demonstrated an effectiveness promotion of lettuce productivity and soil fertility.

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4.
The vesicular arbuscular fungusGlomus mosseae (Nicol. & Gerd.) Gerd. & Trappe was retrieved from citrus trees growing in loess soil in the Negev region of Israel. Inoculation of citrus seedlings with the mycorrhizal fungus greatly increased the growth of plants in soil low in phosphorus. Rough lemon responded more than Sour orange. Vesicular arbuscular mycorrhiza caused higher concentrations of P and Cu and lower concentrations of N, K and Ca in leaves of inoculated plants.  相似文献   

5.
The impact of colonization by the arbuscular mycorrhizal fungus (AMF) Glomus mosseae on tomato root necrosis caused by the soil-borne pathogen Phytophthora parasitica was investigated. Studies in situ permitted infection loci to be identified and the effects of the AMF on numbers to be elucidated. Effects were significant and, 7 and 16 days after inoculation with zoospores of the pathogen, roots of plants colonized by the AMF had 39% and 30%, respectively, fewer infection loci than those that were not. Concurrent studies of the rate of spread of necrosis within roots showed no changes caused by the AMF. At harvest, 26 days following inoculation with the pathogen, 61% of roots of noncolonized plants were necrotic compared with only 31% in AMF-colonized plants. It is concluded that effects on numbers of infection loci are one mechanism via which AMF achieve biocontrol of this pathogen in tomato. Measures of the effects of the AMF on root system architecture suggest that no significant changes occur and are thus not the reasons for the reduction in infection loci. The implications of these data for agricultural practice and biocontrol research are discussed.  相似文献   

6.
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7.

Arbuscular mycorrhizal fungi (AMF) establish a mutualistic symbiosis with several plants and play a key role in improving plant growth, tolerance to abiotic and biotic stresses as well as the soil structure. This work aimed at elucidating the AMF temperature stress modulating impact on four pearl millet lines plant growth and soil aggregation. Experimental trials were carried out in both greenhouse and growth chamber to determine the response of the four millet lines to inoculation with two AMF strains (Rhizophagus aggregatus and Funneliformis mosseae) under heat and non-stress conditions. We first investigated the mycorrhizal colonization (MC) and the mycorrhizal growth response (MGR) of millet lines in relation with their soil aggregation potential (root adhering soil/root biomass, MAS/RB) in the greenhouse. Secondly, the four millet lines were grown in two separated growth chambers and subjected to a day/night temperature of 32/28?°C as the control treatment and 37/32?°C as the temperature stress treatment. Plant growth, mycorrhization rate and several physiological, mycorrhizal and soil parameters were measured. Results showed that the mycorrhization rates of millet lines were low and not significantly different. Funneliformis mosseae (31.39%) showed higher root colonization than Rhizophagus aggregatus (22.79%) and control (9.79%). The temperature stress reduced the mycorrhizal colonization rate, shoot and root biomass, and the soil aggregation for all tested lines. L220 and L132 showed more MC rate and MGR than the other lines under control and high-temperature treatment. The MGR was significantly better under temperature stress conditions than in the control. Under the temperature stress conditions, inoculation with R. aggregatus and F. mosseae increased chlorophyll concentration, root dry weight and shoot dry weight as compared to non-inoculated plants. AMF inoculation, particularly with F. mosseae had a positive influence on the tolerance of millet lines to temperature stress. This study demonstrates that AMF play an important role in the response of these four millet lines to temperature stress. AMF is therefore an important component in the adaptation of crops to climatic variations in Sub-Saharan Africa.

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8.
丛枝菌根菌丝桥传递作用对烟草抗病性相关酶活性的影响   总被引：4，自引：2，他引：2  
为明确供体与受体植株间菌丝桥传递抗病信号对受体植株生长以及抗病性相关酶活性的影响,利用丛枝菌根真菌在供体与受体烟苗植株间建立菌根菌丝桥,对供体植株接种青枯菌的方法进行研究。结果表明:在供体烟苗接种丛枝菌根真菌条件下,再接种青枯菌,比只有菌丝连接的受体烟苗叶片内的过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)、苯丙氨酸解氨酶(phenylalanine ammonialyas,PAL)的活性分别提高了21%、29%和14%,地上部干重和植株磷含量也有相同的趋势;而在不接种丛枝菌根真菌条件下,供体烟苗接种青枯菌与否对酶的活性、植株干重及氮、磷含量均无显著影响。表明供体烟苗产生的抗病信号可以通过菌丝桥传递给受体烟苗,增强受体烟苗的抗病性。  相似文献   

9.
Among other benefits, arbuscular mycorrhizal (AM) fungi may increase plant tolerance to root diseases. The research on the underlying mechanisms requires growth conditions that are both controlled and realistic. To study these interactions, a semiaxenic phototrophic system was developed in which the roots grow in a controlled environment and can be inoculated with both pathogenic and symbiotic fungi. Micropropagated fig plantlets were grown in containers having shoots in the outside and roots in a growth medium without sugar, inoculated or not with the AM fungus Rhizophagus irregularis and the pathogenic fungus Armillaria mellea. Dual inoculated plants developed the mycorrhizal association and pathogen infection symptoms. Mycorrhizal inoculation lowered disease index and increased plant growth. Colonization of A. mellea in fig roots was quantified by real-time PCR, showing that R. irregularis did not significantly lower the quantity of Armillaria, suggesting that other mechanisms were involved in increased tolerance to the pathogen. The results show that the system proposed is suitable to study the triple interaction involving plant, AM and root pathogenic fungi.  相似文献   

10.
Over the last decades, tillage, chemical fertilizers, and pesticides have reduced the beneficial fungal population size in arable soils. Though soil inoculation can be a practical way to restore arbuscular mycorrhizal fungi (AMF) population size, weeds may also be benefited, as well. This study was aimed to evaluate the effect of three AMF species (Funneliformis mosseae, Rhizoglomus fasciculatum, and Rhizoglomus intraradices) on photosynthetic rate, secondary metabolites content, reproductive organs percentage and nutrient uptake in Solanum nigrum L. and Digitaria sanguinalis L. weed species. Our results showed species variation in response to AMF inoculation, so that, while inoculation with R. intraradices fungal species decreased total biomass in S. nigrum plants significantly, it increased total biomass of D. sanguinalis plants by 26–49%. In addition, inoculation with F. mosseae species increased phenol, anthocyanin, and total terpenoid content in S. nigrum plants much more than D. sanguinalis. Increased photosynthetic rate, secondary metabolites content, and flowering percentage in AMF‐inoculated S. nigrum plants show the enhanced competitive ability and allelopathic potential of this weed when associated with AMF, which makes it a good competitor against other plant species in the environment.  相似文献   

11.
Interactions between Plasmopara helianthi, Glomus mosseae and two plant activators DL--amino-n-butyric acid (BABA) and CGA 245704 (acibenzolar-S-methyl (BTH)) in sunflower plants susceptible to downy mildew were studied in four experiments using different methods of treatment and pathogen inoculation. Both chemicals were applied as soil drenches and foliar sprays, whereas P. helianthi infection was obtained by root and cotyledon inoculations of the seedlings. Soil drenches at the rates of 50 and 100mgkg–1 soil of BABA and BTH given 1 and 3 days before P. helianthi inoculation, respectively to mycorrhizal plants, provided moderate protection against the pathogen (about 50–55%). Morphological changes and decrease in mycorrhizal colonization in roots of BTH-treated plants and in BTH-treated mycorrhizal plants were also observed. Delay in the emergence and reduction of the root systems were more evident at the highest concentration but decreased with time. These effects were absent with the BABA treatment.Foliar spray treatment of BABA and BTH, applied at 4000 and 200µgml–1, respectively (1 day post-inoculation) to mycorrhizal plants provided good protection (about 80%) against P. helianthi foliar infections. No effects on mycorrhizal colonization or on root systems were observed. In vitro tests on the effect of the compounds on the mycorrhizal fungus showed that the germination of G. mosseae sporocarps increased with BABA treatment whereas it was greatly inhibited by BTH treatment.  相似文献   

12.
Piriformospora indica (Sebacinaceae) is a cultivable root endophytic fungus. It colonizes the roots of a wide range of host plants. In many settings colonization promotes host growth, increases yield and protects the host from fungal diseases. Evaluation was made of the effect of P. indica on fusarium head blight (FHB) disease of winter (cv. Battalion) and spring (cv. Paragon, Mulika, Zircon, Granary, KWS Willow and KWS Kilburn) wheat and consequent contamination by the mycotoxin deoxynivalenol (DON) under UK weather conditions. Interactions of P. indica with an arbuscular mycorrhizal fungus (Funneliformis mosseae), fungicide application (Aviator Xpro) and low and high fertilizer levels were considered. Piriformospora indica application reduced FHB disease severity and incidence by 70%. It decreased mycotoxin DON concentration of winter and spring wheat samples by 70 and 80%, respectively. Piriformospora indica also increased aboveground biomass, 1000‐grain weight and total grain weight. Piriformospora indica reduced disease severity and increased yield in both high and low fertilizer levels. The effect of P. indica was compatible with F. mosseae and foliar fungicide application. Piriformospora indica did not have any effects on plant tissue nutrients. These results suggest that P. indica might be useful in biological control of Fusarium diseases of wheat.  相似文献   

13.
ABSTRACT The capacity of the arbuscular mycorrhizal fungus Glomus intraradices in reducing the presence of Fusarium solani f. sp. phaseoli in bean plants and the surrounding mycorrhizosphere soil was evaluated in a compartmentalized experimental system. Quantification of the pathogen and the symbiont in plant tissues, the soil regions of the mycorrhizosphere (rhizosphere and mycosphere), and the bulk soil was accomplished using specific polymerase chain reaction (PCR) primers in real-time PCR assays, culture-dependant methods, and microscopic determination techniques. Nonmycorrhizal bean plants infected with the pathogen had distinctive Fusarium root rot symptoms, while infected plants previously colonized by G. intraradices remained healthy. The amount of F. solani f. sp. phaseoli genomic DNA was significantly reduced in mycorrhizal bean plants and in each mycorrhizosphere soil compartment. The presence of G. intraradices in the mycorrhizosphere was not significantly modified, although the mycorrhizal colonization of roots was slightly increased in the presence of the pathogen. The results suggest that the reduced presence of Fusarium as well as root rot symptoms are caused by biotic and/or abiotic modifications of the mycorrhizosphere as a result of colonization with G. intraradices.  相似文献   

14.
Three experimental treatments consisting of inoculation with an arbuscular mycorrhizal fungus, application of a synthetic antimicrobial peptide or application of a resistance inducer, were evaluated in Madagascar periwinkle as control methods for rubus stunt and stolbur diseases caused by ‘Candidatus Phytoplasma rubi’ and ‘Candidatus Phytoplasma solani’, respectively. Two experiments were conducted under controlled environment conditions. In the first experiment, 4 months after graft‐inoculating the phytoplasmas, the root colonization achieved by Rhizophagus irregularis significantly reduced both disease symptoms and the frequency of detection of the pathogens by real‐time PCR. In the second experiment, the antimicrobial peptide BP100 totally prevented disease symptoms, despite the molecular detection of the phytoplasmas in 75% and 50% of the plants inoculated with ‘Ca. Phytoplasma rubi’ and ‘Ca. Phytoplasma solani’, respectively, and was more effective than benzothiadiazole (BTH) at increasing resistance against the pathogenic infections. A potential combination of early mycorrhizal inoculation and BP100 antimicrobial peptide application is envisaged as a future control strategy for phytoplasma diseases.  相似文献   

15.
In the present study, arbuscular mycorrhizal fungi (AMF) (Glomus monosporus, Glomus deserticola, Glomus clarum and a complex of native AMF coming from the Aoufous date palm grove in the south of Morocco) have been shown to protect date palm seedlings against bayoud disease. Treatment with AMF reduced disease severity by 8–77% depending on the AMF isolate used. In addition, all mycorrhizal fungi stimulate significantly shoot height and biomass and increase the number of leaves per plant. The plants associated with Aoufous complex present the best improvement of plant growth and great effectiveness in reducing bayoud disease incidence. Moreover, the AMF induce change in activities of two defence-related enzymes (peroxidases and polyphenoloxidases). The potential involvement of this induced biochemical defence reaction in protecting date palm against bayoud is discussed.  相似文献   

16.
利用温室盆栽试验研究水分胁迫下接种丛枝菌根（Arbuscular mycorrhizal,AM）真菌和根瘤菌（Rhizobium meliloti）对沙打旺(Astragalus adsurgens Pall.) 生长和养分吸收的影响。在土壤相对含水量65%和35%条件下,分别设不接种（对照）、单接根瘤菌、单接摩西球囊霉(Glomus mosseae)和双接根瘤菌与摩西球囊霉等4个处理。结果发现：干旱胁迫显著抑制沙打旺AM真菌侵染率（P<0.05）,而接种根瘤菌在两种水分条件下均显著促进摩西球囊霉对沙打旺根系的侵染（P<0.05）。接种AM真菌不仅显著提高沙打旺对P的吸收（P<0.05）,而且明显促进根瘤的生长。无论是在干旱条件下或是在正常供水条件下,双接根瘤菌与摩西球囊霉处理对沙打旺生长及养分吸收的效应显著高于单接菌处理,植株地上部、地下部生物量以及N、P、K等吸收量均为最大。结果表明：AM真菌与根瘤菌双接种技术在干旱、半干旱区受损生态系统的植被恢复中具有一定的应用潜力。  相似文献   

17.
Biological control of soil-borne pathogens by arbuscular mycorrhizal (AM) fungi has been repeatedly demonstrated. However, their role in the control of above-ground hemibiotrophic pathogens is less conclusive. Here, we investigated in vitro the impact of an AM fungus on Phytophthora infestans in potato plants. The leaf infection index was decreased in mycorrhizal potato plants. Real-Time Quantitative PCR revealed the induction of two pathogenesis related genes (PR1 and PR2) in the leaves of mycorrhizal plants shortly after infection with P. infestans. These results suggested a systemic resistance in mycorrhizal plants, related to the priming of the two PR genes in potato.  相似文献   

18.
 近年来, 小麦孢囊线虫(cereal cyst nematodes, CCN:主要病原为燕麦孢囊线虫Heterodera avenae)对小麦(Triticum aestivum)的危害日益严重, 亟待探索新的生防途径。丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)作为环境功能生物, 对寄主植物具有生物药肥双重作用, 不仅能促进植物吸收利用养分, 而且能拮抗土传病原物、提高植物抗病性。本研究以AMF与CCN相互作用为切入点, 试图明确AMF与CCN相互作用关系, 并科学评价不同AMF抑制CCN、降低病害的效应。试验于温室盆栽条件下进行, 设接种AMF Gigaspora margarita(Gi.m)、Glomus mosseae(G.m)、Glomus intraradices(G.i)、Glomus versiforme(G.v)、Gi.m +G.m+G.i+G.v、CCN、CCN+Gi.m、CCN+G.m、CCN+G.i、CCN+G.v、CCN+Gi.m+G.m+ G.i+G.v和不接种对照(CK)共12个处理。结果表明, 接种AMF各处理均能降低小麦孢囊线虫侵染率、土壤中孢囊数和根内J2数量, 其中Gi.m处理抑制效果最大;CCN不同程度减少AMF侵入点数和产孢数量。Gi.m 和CCN+Gi.m处理的根内丛枝着生数量最多, 而后者根内的超氧化物歧化酶、苯丙氨酸解氨酶和过氧化氢酶活性显著高于其他处理、丙二醛含量则显著低于其他CCN+AM真菌处理。Gi.m和G.i处理的小麦株高、地上部干重高于其他处理;Gi.m 和CCN+Gi.m的处理的单穗重和单株产量均高于其他处理。表明AMF能不同程度拮抗CCN、促进小麦生长和提高产量, 其中, Gi.m是高效菌种。结论认为, AMF与CCN之间存在一定相互抑制作用, AMF能通过诱导植株防御反应拮抗CCN。  相似文献   

19.
Verticillium dahliae alters water status and consequently, growth and production of pepper plants. On the other hand, arbuscular mycorrhizal fungi (AMF) can reduce damage caused by specific soil-borne plant pathogens and improve drought resistance of pepper. Therefore, one objective of this research was to assess if AMF can modify the development of Verticillium-wilt in pepper plants. A second objective was to study the influence of plant phenology at the moment when V. dahliae was inoculated on the possible biocontrol of the disease by AMF. Results suggested that AMF reduce the deleterious effect of V. dahliae on pepper growth and yield. However, bioprotection against Verticillium-wilt was conditioned by plant phenology at the moment of pathogen attack. The highest efficacy of AMF occurred when V. dahliae was inoculated during the vegetative stage of plants. AMF allowed leaf relative water content to be maintained for longer and delayed both the appearance of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants. These benefits on plant physiology increased pepper yield.  相似文献   

20.
The effects of the arbuscular mycorrhizal (AM)-fungi Glomus intraradices and Glomus claroideum on pea root-rot development caused by the pathogen Aphanomyces euteiches were investigated in a greenhouse pot-experiment, over the course of three harvests, using oospores as pathogen inoculum. Signature whole cell fatty acids 16:15c and 14:19 were used to quantify AM-fungi and A. euteiches, respectively in both roots and soil. Disease incidence was reduced in AM plants, though this effect was more pronounced in plants with G. intraradices than plants with G. claroideum, and corresponded with a greater mycorrhiza development, both intra- and extra radical in plants with G. intraradices than with G. claroideum. At the final harvest, percentage of root length with oospores was similar in roots of mycorrhizal and non-mycorrhizal plants. Despite the fact that pea root-rot development was only slightly lower in mycorrhizal plants compared to that of non-mycorrhizal plants, in terms of shoot growth and disease severity, mycorrhizal plants suffered less. This suggests a possible mycorrhiza-induced tolerance against pea root-rot. Furthermore, the degree of tolerance induction differed between the two AM-fungi included in the present study.  相似文献   

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