Effect of microelement and chemical fungicides on biocontrol effect of Trichoderma T23

Recently there have been many reports about soil diseases controlled by Trichoderma, but few could be applied on agriculture production in large areas. T23 isolated from soil around plant roots in the field by Biopesticide Engineering Center of Shenyang Agricultural University could control effectively Cucurbits Fusarium Wilt. The effects of 9 microelements which include copper, zinc, iron, boron, molybdenum, calcium, manganese, magnesium, potassium and frequently-used chemical fungicides, such as-carbendazim, thiram, thiophanate-methyl, chlorothalonil and hymexazol on the growth and the amounts of spores of Fusarium oxysporum FJ and Trichoderma T23 were studied. The effects of those factors on control effect of T23 to melon diseases were discussed and gave basis for the screening of synergistic agents and fungicides in controlling synergistically the pathogen. The results showed that copper sulfate, zinc sulfate, ferric sulfate and boric acid at concentration of 10-1000 μg/mL had the stronger inhibition to F. oxysporum, while weaker inhibition to Trichoderma. Ammonium molybdate, ferrous sulfate, calcium sulfate and potassium dihydrogen phosphate were the ideal the synergistic agent for accelerating the growth and sporulation of Trichoderma, and germination of melon seeds and growth of melon radicle. Melon Fusarium wilt was controlled by Trichoderma combined with ammonium molybdate and calcium sulfate. The relative control effect reached to 73.95%-71.36%. Several fungicides used generally in soil had a different effect on the growth of F. oxysporum and Trichoderma. Carbendazim appeared a strong inhibition to the growth of two strains, with EC50 of 3.01 mg/L and 0.75. mg/L, respectively. Trichoderma had the strong resistance to thiram which control to Fusarium oxysporum was not ideal in field. Hymexazol which EC50 was 261 mg/L and Trichoderma had the synergistical effect on controlling to F. oxysporum. Trichoderma could reproduce in soil treated with hymexazol at ratio of 2000-4000. Relative control effect of hymexazol combined with Trichoderma to oxysporum reached to 79.26%,. which was higher by 15.19% and 38.75% than the solo controlling effect respectively.

Advances in biocontrol mechanism and application of Trichoderma spp.for plant diseases

Trichoderma spp. is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens, it has universal distribution and economic importance. This article reviewed the researches on biocontrol mechanism for plant diseases and application of Trichoderma spp., especially Trichoderma harzianum in recent years

Trichoderma spp. capable of growing at low temperatures with biocontrol potential

@Szakacs G$Technical University of Budapest, Department of Agricultural Chemical Technology, 1111 Budapest, Gellert ter 4, Hungar@Tavaszi A$Technical University of Budapest, Department of Agricultural Chemical Technology, 1111 Budapest, Gellert ter 4,

Colonization and degradation of senescent flowers of zucchini squash by Trichoderma harzianum YC459, a biocontrol agent of gray mold, Botrytis cinerea

In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato, strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderma harzianum YC459 (TORY, JGreen Inc.), a biocontrol agent with good and consistent efficacy as chemical fungicides for the control of gray mold rot caused by B. cinerea. The mechanism for selective colonization of senescent floral tissues by T. harzianum YC459 was elucidated using fresh and senescent (4 days and 14 days after pollination, respectively) floral tissues of zucchini squash (Cucurbita moschata Duchesne) . The spores of T. harzianum YC459 were produced much more on water agar and liquid culture media supplemented with 5% dry powder of senescent floral tissues than with fresh tissues during 15 days incubation. Mycelial growth was also much better in the media with senescent tissues than with fresh tissues. Enzyme activities of carboxymethyl cellulase, amylase and polygalacturonase in the liquid media, which might be involved in the colonization and degradation of tissues by T. harzianum YC459 were compared. The activities of three enzymes were significantly higher in the media with senescent floral tissues than with fresh floral tissues reaching to the maximum during 9 to 12 days of incubation. Especially, the activities of carboxymethyl cellulase and polygalacturonase of T. harzianum YC459 were much higher than those of other Trichoderma species, T. asperellum, T. viride and T. koningii in the liquid media with senescent floral tissues. Based on the results, the selective colonization and degradation of senescent floral tissues, an important habitat for B. cinerea, may be another mechanism for the biocontrol of gray mold rot of vegetables by T. harzianum YC459.

Nutrient activation of Trichoderma fungal spores for improved biocontrol activity

The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum P1 (ThP1) to suppress Botrytis cinerea was investigated in laboratory, greenhouse and field trials. Preliminary nutrient activation at 21 ℃ accelerated subsequent germination of the antagonist at temperatures from 9 ℃ to 21 ℃; at ≥ 18 ℃ the germination time of preactivated ThP1 conidia did not differ significantly from that of B. cinerea. When coinoculated with B. cinerea, concentrated inocula of preactivated but ungerminated ThP1 conidia reduced in vitro germination of the pathogen by ≥ 87% at 12 ℃ to 25 ℃; initially-quiescent conidia achieved this level of suppression only at 25 ℃. Application of quiescent ThP1 conidia to detached strawberry flowers in moist chambers reduced infection by B. cinerea by ≥85% at 24 ℃, but only by 35% at 12 ℃. Preactivated conidia reduced infection by ≥60% at 12 ℃. Both quiescent and preactivated conidia significantly reduced latent infection in greenhouse-grown strawberries at a mean temperture of 19 ℃, while only preactivated conidia were effective in the field at a mean temperature of 14 ℃ on the day of treatment application. Trichoderma biocontrol isolates are most effective as highly concentrated inocula. Their antagonism to other fungi may be a result of pregermination respiration. In a nutrient-rich medium, almost all Trichoderma. atroviride P1 (P1) conidia initiated germination processes and increased respiration, even in dense suspensions. When 1×107 P1 conidia per mL were coinoculated with 1×105 B. cinerea conidia per mL, dissolved oxygen fell to <1% within 2 h and the pathogen failed to germinate. More dilute P1 suspensions consumed oxygen slowly enough to allow coinoculated B. cinerea to germinate. On nutrient-poor media, fewer P1 conidia initiated germination. Oxygen consumption by the inoculum and inhibition of B. cinerea were enhanced when P1 conidia were nutrient-activated before inoculation. Pregermination respiration also affected the competitive capacity of the antagonist on solid substrates, where respiratory CO 2 stimulated germination rate and initial colony growth. These parameters were directly correlated with inoculum concentration (R2≥ 0.97, P<0.01). After initiating germination, Trichoderma conidia became more sensitive to desiccation and were killed by drying after only two hours incubation on a nutrient-rich substrate at 23 ℃. Consideration of these effects of germination initiation on the competitive potential of Trichoderma in biological control will bee discussed.

Biocontrol of Rhizoctonia solani with Trichoderma Spp.

From over 800 fungal strains of Tri-choderma Spp. , 6 strains were foundto greatly inhibit the growing of Rhi-zocotonia solani, the pathogen of ricesheath blight in dual culture. Amongthem, strain T3 was the best antago-nist, which reduced the growing ofthe pathogen by 52.54% (Table 1).

3株木霉(Trichoderma spp.)对华山松疱锈病菌锈孢子的破坏作用

从不同来源的茶藨生柱锈锈孢子堆和疱锈病枝干上分离获得3株木霉,室内生测结果表明,3株木霉的菌丝和培养滤液对锈孢子壁有较强的破坏作用;菌株TR2和TR3在锈孢子堆上生长速度快,锈孢子死亡率随孢子壁破坏率的增加而升高,锈孢子壁对孢壁降解酶有强烈诱导作用;TR1对锈孢子壁的破坏作用弱于TR2和TR3,但在PD培养液中有较强的产毒能力,锈孢子壁能抑制TR1菌株产毒。

Trichoderma viride Strains against Vegetable Grey Mold in Greenhouse

[Objective] The paper aimed to study the control effects of live spore preparations of Trichoderma viride strains against vegetable grey mold in greenhouse. [Method] Trichoderma viride strains NW-411 live spore preparations were prepared by solid-state fermentation,106-107 spore/g diluent was made to conduct field control experiment,traits change of cucumber and tomato plants inoculated grey mold were investigated,control effect was calculated. [Result] Cucumber and tomato plants without dilution treatment of T. viride spores could be infected with different changes in trait. T. viride spore preparations had a significant preventive effect on greenhouse cucumber and tomato gray mold,the optimal concentration of spores was in the range of 2.3×10^6-2.3×10^7 spore/g. The incidence of cucumber and tomato plants were reduced to 4.2% and 3.1%,the incidence rate decreased 29.8% and 39.1% compared with plants without treatment,biological control effect was over 87%,and the plant growth can be enhanced obviously. [Conclusion] Live spores preparation of T. viride not only had a significant effect on grey mold,but also significantly enhanced the plants growth in greenhouse,which is a safety and environmental protection biological agent,and worthy to be widely spread in large-scale green vegetable production.

木霉(Trichoderma spp.)对植物土传病害生防机制的研究进展

应用木霉防治植物土传病害已经成为目前生物防治研究的热点。随着分子生物学与生物工程等技术的不断发展,对木霉防治病原微生物的生防机制研究已经取得较大的进展。本文主要从竞争作用、重寄生作用、抗生作用、诱导抗性、促生作用、协同拮抗等方面对木霉的生防机制进行综述,并阐述了防病的分子机理,以期使木霉更加合理地应用到土传病害防治领域中。同时,文章也对木霉的实际应用与可能出现的问题进行分析,并对今后的研究工作进行展望。

Screening of antagonistic Trichoderma strains and their application for controlling stalk rot in maize

Maize is one of the major crops in China, but maize stalk rot occurs nationwide and has become one of the major challenges in maize production in China. In order to find an environment-friendly and feasible technology to control this disease, a Trichoderma-based biocontrol agent was selected. Forty-eight strains with various inhibition activities to Fusarium graminearum, and Fusarium verticillioides were tested. A group of Trichoderma strains(DLY31, SG3403, DLY1303 and GDFS1009) were found to provide an inhibition rate to pathogen growth in vitro of over 70%. These strains also prevented pathogen infection over 65% and promoted the maize seedling growth for the main root in vivo by over 50%. Due to its advantage in antifungal activity against pathogens and promotion activity to maize, Trichoderma asperellum GDSF1009 was selected as the most promising strain of the biocontrol agent in the Trichoderma spectrum. Pot experiments showed that the Trichoderma agent at 2–3 g/pot could achieve the best control of seedling stalk rot and promotion of maize seedling growth. In the field experiments, 8–10 g/hole was able to achieve over 65% control to stalk rot, and yield increased by 2–11%. In the case of natural morbidity, the control efficiency ranged from 27.23 to 48.84%, and the rate of yield increase reached 11.70%, with a dosage of Trichoderma granules at 75 kg ha^-1. Based on these results, we concluded that the Trichoderma agent is a promising biocontrol approach to stalk rot in maize.

Mechanisms involved in biocontrol and plant induced resistance by richoderma. asperellum (T. harzianum T-203)

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderma spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants. In our laboratory we are studying the mechanism of induction of systemic responses against angular leaf spot disease of cucumber-Pseudomonas syringae pv. lachrymans (Psl), following application of T. asperellum to the root system. The protection afforded by the biocontrol agent is associated with concomitant accumulation of secondary metabolites of a phenolic nature and mRNA of two defense genes: the phenylpropanoid pathway gene phenylalanine ammonia lyase (PAL) and the octadecanoid pathway gene hydroxyperoxide lyase (HPL). Combining gene expression analysis, measurements of signal molecules levels and use of specific hormone inhibitors we could demonstrate that the JA/ethylene signaling pathway is involved in the systemic response induced by Trichoderma. A molecular analysis of Trichoderma genes and proteins differentially induced by root interaction reveals that molecules related to phytopathogenicity, but also known as elicitors of plant defense responses, are transiently activated in planta, enabling at the same time intracellular colonization and induction of systemic defense responses pathways. It appears that Trichoderma as a beneficial soil fungus has several efficient modes of action.

Construction of engineering Trichoderma strains and their characteristics against tomato gray mold

The transformed Trichoderma strains Ttrm31, Ttrm34 and Ttrm55 were obtained from Trichoderma wild strain T21 mutated by REMI technique for more effective biocontrol of tomato gray mold (Botrytis cinerea) with Trichoderma agent. Those transformants appeared much better in biocontrol activity in vitro or in vivo against tomato gray mold were better than that of wild strain T21. The main results were as follow: The transformed Trichoderma strains were detected in their genetic stability by consecutive culture for several generations, growing them on hygromycin-contained medium, and then further detection by PCR. The results showed that the REMI was very useful to construct the transformed Trichoderma strains even though some non-transformants concurrently appeared with positive reaction, but which could be distinguished and avoided by southern blotting. The biological characteristics of transformed Trichoderma strains varied among themselves or differed in parts as compared with wild one. Much changes were detected in the conidia germination, sporulation, tolerance to high-temperature, growth at a certain range of temperature, cultural characteristics under different pH condition as well as utilization of carbon and nitrogen nutrition. Some transformants performed better in the most of mentioned characteristics compared with wild one, others not. For example, conidia germination of strain Ttrm31 was higher than that of wild strain T21. Conidia productivity of Ttrm34 was higher than that of wild strain T21. As the tolerance to high-temperature, Ttrm31 and Ttrm34 were enhanced remarkably relative to wild strain. Meanwhile, it was interested that the growth of transformed Trichoderma strains improved much once treated under high-temperature (50℃) for 1 h. Differently, Ttrm55 grew faster at low-temperature (15℃) ,Ttrm31,Ttrm34 and Ttrm55 grew fast as the wild one at 20-30℃. The transformed Trichoderma strains differed in cultural morphology including color and sporulation at different pH, and even on PDA. Protein and asparagines were screened as better nitrogen, and glucose and maltose as better carbon source. There were several mechanisms expected among transformed Trichoderma strains against Botrytis cinerea. Ttrm31, Ttrm55 and Ttrm111,for instance, had more ability for the nutrition and space competition over pathogen, while Ttrm34 and Ttrm76 inhibited pathogen in the way of mycoparasitism which subsequently confirmed by the higher activities of chitinase and β-glucanase needed for parasitizing pathogen. Similarly Ttrm34 and Ttrm55 were higher in both enzyme activities than those of T21. Additionally a putative role of induced resistance might be involved in the biocontrol mechanism because a series of defensive enzyme in tomato were increased in activities such as PAL, POD, CAT, PPO, SOD, chitinase and β-glucanase once tomato plants treated with transformants, but the level of the induction depended on the transformed Trichoderma strains used. Comparatively, PAL, POD, CAT, PPO and chitinase activities in tomato induced by Ttrm55 were great different from other transformants except SOD and β-glucanase. SOD activity in tomato stimulated by strain Ttrm55 was higher than that induced by others, while β-glucanase activity was lower. The CAT, PAL, PPO activities induced by Ttrm31 were higher than those by other transformants, but lower in SOD, POD and chitinase than those by others. In general POD, PPO, PAL and chitinase activities were higher in tomato induced by Ttrm34 than other enzymes. β-glucanase activities induced by T21 were higher than those of others, but contrary in other enzymes. Transformed Trichoderma strains had the same ability in the colonization on the tomato leaf surface as the wild strain T21, however no much differences were seen between transformants and wild one in the trait. More importantly 3 transformed Trichoderma strains were proved to be very effective in the control of gray mold in flowers and leaves and 14%-18.5% and 7%-9% were increased over wild strain

Soil application of Trichoderma asperellum GDFS1009 granules promotes growth and resistance to Fusarium graminearum in maize

Of diseases affecting maize(Zea mays), Fusarium graminearum is one of the most common pathogenic fungi that cause stalk rot. In the present study, the Trichoderma asperellum GDFS1009 strain was shown to be an effective biocontrol agent against stalk rot. In a confrontation culture test, Trichoderma strain displayed an approximately 60% inhibition rate on the mycelial growth of F. graminearum. In pot trials, the application of 2 g/pot of T. asperellum GDFS1009 granules had the best control effect on stalk rot at the seedling stage(up to 53.7%), while the average plant height and fresh weight were also significantly improved. Additionally when fertilizer was added at 8 g/pot, the application of 3 g/pot of Trichoderma granules had the best control effect on maize stalk rot(40.95%). In field trials, when inoculating F. graminearum alone, the disease index for inoculating was 62.45, but only 31.43 after treatment with T. asperellum GDFS1009 granules, suggesting a control efficiency of 49.67%. Furthermore, in a naturally F. graminearum-infected field, Trichoderma granules, when applied for 3 consecutive years, showed significant control of stalk rot and increased yields.

Studies on the control of Fusarium oxysporum f.sp. cubense with Trichoderma

One hundred and fifty one isolates of Trichoderma were collected mainly from more than 40 soil samples and other materials in Guangdong Province (including Chigang, Zhanjiang, Wuchuan, Panyu, Zhaoqing, Dongguan, Humen, Qingyuan, Guanzhou) and the soil samples were also from different plant rhizosphere (including rice, different fruits and different vegetables). It was shown that 39 isolates of Trichoderma grew faster than other isolates using growth velocity experiments. The 39 isolates could effectively inhibit Fusarium oxysporum f.sp. cubense (E.F.Sm) Sny.&Hans. by dual cultural experiments. The inhibited activity included the antifungal activities of its metabolite, mycoparasitic activities and the lytic enzymes by dual culture, electronic microcopy and enzyme assay. At present, studies on the taxonomy of the 151 isolates of Trichoderma are carried out in our experiments, some Trichoderma species aggregates will be identified according to the taxonomy system revised by Rifai and Bissett.

Heterologous expression of the glucose oxidase gene in Trichoderma atroviride leads enhanced ability to attack phytopathogenic fungi and induction of plant systemic disease resistance

A transgenic strain of Trichoderma atroviride that expresses the Aspergillus niger glucose oxidase gene goxA under a homologous pathogen-inducible promoter (nag1) has been constructed, with the aim of increasing the ability of this biocontrol agent (BCA) to attack phytopathogenic fungi and enhance plant systemic disease resistance. The sporulation and growth rate of the transgenic progenies were similar to the wild-type strain P1. goxA expression occurred immediately after contact with the plant pathogen, and the glucose oxidase formed was secreted extracellularly. The transformed strain SJ3 4, containing 12-14 copies of the transgene, produced significantly less N-acetyl-glucosaminidase and endochitinase then wild type. However, the ability of its culture filtrate to inhibit the germination of Botrytis cinerea spores was increased by about 3-fold. In comparison to P1, the transgenic strain more quickly overgrew and lysed in vitro the pathogens Rhizoctonia solani and Pythium ultimum. In assays in vivo SJ3 4 showed a highly improved biocontrol ability in soil heavily infested with those pathogens, where the wild type was unable to protect the plant and allow seeds to germinate. The Trichoderma-gox was able to induce a much higher level of systemic resistance against the foliar pathogen B. cinerea, as compared to the parent strain. This work demonstrate that i) heterologous genes driven by pathogen-inducible promoters can improve the biocontrol and Induced Systemic Resistance properties of fungal BCAs such as Trichoderma spp., and ii) these microbes can be used as vectors to provide the plant with useful molecules able, for instance, to increase pathogen

Identification of novel Trichoderma hamatum genes expressed during mycoparasitism

Trichoderma species are currently used as biocontrol agents for crop diseases caused by a number of fungal plant pathogens. However, their biocontrol performance in the field can be unreliable and it is likely that more consistent performance could be achieved through knowledge and manipulation of the genes involved. For example, induction of the genes could be optimised for variable environmental and physiological conditions, superior strains could be selected more effectively and novel strains could be created. One method by which Trichoderma species accomplish biocontrol is mycoparasitism. Several genes involved in the mycoparasitic interaction have previously been characterised, however these consist predominantly of those that encode enzymes that degrade fungal cell walls. In the current study subtractive hybridisation was used to target genes expressed when Trichoderma hamatum and the plant pathogen Sclerotinia sclerotiorum were cultured together, subtracting genes expressed when each are grown individually. This experimental design has the potential to yield T. hamatum genes involved in mycoparasitism of S. sclerotiorum, and S. sclerotiorum genes up-regulated in host defence. The cDNA fragments yielded by the subtraction were characterised with respect to expression, sequence and species of origin. A number of novel T. hamatum genes which were up-regulated during mycoparasitism were identified.

Commercial development of Trichoderma species for control of soil-borne vegetable diseases and their integration into standard crop management practices

A 10 year research programme at Lincoln University, investigating the use of Trichoderma species for biological control of soil-borne diseases of vegetable crops, has resulted in the development of two commercial products. Trichodry TM. 6S and Trichoflow TM. 6S based upon Trichoderma hamatum isolate 6SR4, are used to control Sclerotinia lettuce drop disease. The Trichodry 6S product is formulated as a dry flake, which is incorporated into nursery seedling mix and the Trichoflow 6S is a wettable powder which is used as a top-up drench before planting. The treatment stimulates seedling establishment and vigour and protects the developing seedling from Sclerotinia minor infection after transplanting in the field.The second commercial product is Trichopel TM. Ali 52, based upon Trichoderma atroviride isolate C52, which is used to control Sclerotium cepivorum, the causal agent of Allium white rot disease. The product is formulated as a granule and applied into the furrow at planting time. The fungus proliferates in the rhizosphere region and protects the growing seedling from pathogen attack by a combination of nutrient competition, antibiosis and mycoparasitism. The use of Trichopel Ali 52 under low to medium disease pressure in Pukekohe, the main vegetable growing region of New Zealand, gave a three fold cost benefit through yield increases in the 2003-2004 season. Current field development work involves the use of a wettable powder formulation of T. atroviride distributed via a T-tape irrigation system to target mid-season applications of the product to the onion roots. Both products perform well under low to moderate disease pressure but, when there is high disease pressure, an integrated programme is required to give satisfactory control. Current research is focused on gaining a greater understanding of the biotic and abiotic factors, which influence biocontrol activity under field conditions as a means to enhance integrated control approaches. For example, T. atroviride C52, when applied to the planting furrow, is compatible with procymidone, benomyl and captan but not thiram when applied as onion seed treatments. It is also compatible with the majority of other fungicides applied to the onion crop to protect against foliar diseases such as Botrytis and downy mildew. The product can be integrated with the use of the germination stimulant diallyl disulphide (DADS) as long as the Trichoderma product is applied at least two weeks after DADS application. The product is not compatible with the use of nitrogen fertilisers due to the sensitivity of the Trichoderma mycelium to high N, thus, care must be taken to separate fertilizer application from that of the biocontrol product. Expansion of the range of crop diseases targeted by the biocontrol products is currently under investigation with promising results obtained against a number of Botrytis diseases.

哈茨木霉β-葡聚糖酶诱导、纯化及对黄瓜幼苗的促生防病作用

在实验室条件下分别以β-葡聚糖、麦麸和黄瓜枯萎病菌(Fusarium oxysporum)细胞壁作为唯一碳源诱导哈茨木霉菌(Trichoderma harzianum)Th-30发酵产生β-葡聚糖酶,采用硫酸铵盐析和琼脂糖凝胶色谱柱层析法对β-葡聚糖酶进行分离纯化,以津研4号黄瓜为试验材料,探究β-葡聚糖酶对黄瓜幼苗抗性生理指标、形态指标的影响及黄瓜常见土传病害的防控作用。结果表明:不同诱导条件下木霉Th-30发酵产β-葡聚糖酶活性差异显著,经β-葡聚糖诱导发酵的粗酶液酶活性最高,发酵72 h时达75.63 U·mL^(-1);纯化的β-葡聚糖酶比活力为783.56 U·mg^(-1),是粗酶液的45.32倍;5倍液和10倍液β-葡聚糖酶可显著提高黄瓜幼苗的根系活力、游离脯氨酸含量、苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)活性以及根冠比和壮苗指数;β-葡聚糖酶10倍液处理对黄瓜立枯病、黄瓜枯萎病、黄瓜疫病、黄瓜猝倒病、黄瓜菌核病的防效为50.36%~80.63%。

绿木霉NY45对木材腐朽菌的抑制作用及机理研究

为探索木材生物防腐,以绿木霉(Trichoderma virens,NY45株系)为对象,研究其对木材白腐菌彩绒栓菌(Trametes versicolor,Tv)及褐腐菌密粘褶菌(Gloeophyllum trabeum,Gt)的抑制效果并探索抑制机理。结果表明:NY45对两种腐朽菌均有明显的抑制作用,经NY45孢子液处理的毛白杨木材,其耐腐等级从IV级(不耐腐)提升到I级(强耐腐);NY45生长速度远快于木材腐朽菌,可以迅速抢占空间和竞争营养,并能寄生、覆盖、消解木材腐朽菌菌丝,其易挥发性物质对Tv和Gt抑制率分别为18.55%和45.69%,难挥发性代谢产物对两种木材腐朽菌的抑制率均超过90%。NY45有潜力作为木材腐朽生物防治菌进一步开发利用。

当归根际土壤中木霉菌的分离鉴定及拮抗作用

收集甘肃省道地中药材当归根际土壤,采用平板稀释法分离土壤中木霉菌株,利用平板对峙法测定其拮抗作用,结合形态学特征及ITS序列比对鉴定木霉菌株分类地位,以期筛选具有生防作用的菌株并明确其拮抗作用。结果表明,从甘肃省当归根际土壤中分离得到21株木霉菌株,筛选出1株对靶标菌拮抗效果最好的木霉菌株TD-5,鉴定为长枝木霉(Trichoderma longibrachiatum)。TD-5对茄病镰刀菌(Fusarium solani)拮抗作用最好,抑制率为83.31%;对首都叶点霉菌(Phyllosticta capitalensis)的拮抗作用最差,抑制率为24.55%;对三线镰刀菌(Fusarium tricinctum)和胶孢炭疽菌(Colletotrichum gloeosporioides)的拮抗作用介于二者之间。菌株TD-5的挥发性代谢产物对茄病镰刀菌的抑菌效果最好(抑制率79.44%),对胶孢炭疽菌的抑菌效果较差(抑制率64.99%);其难挥发性代谢产物对三线镰刀菌的抑菌效果最好(抑制率70.72%),对茄病镰刀菌的抑菌效果最差(抑制率31.12%)。