拮抗木霉菌的生防机制研究进展

从拮抗木霉菌的抑茵作用机理、诱导抗病性、促进植物生长等方面对木霉菌生防机制的研究进行了综述,并对其应用前景进行了概括。从生防功能的多样性来看,木霉菌是一种理想的生防菌株和难得的生防资源。     

木霉的营养生长及发酵条件

 木霉是一类分布广泛的土壤习居菌,而且对一些病原真菌有很大的生防潜力。大部分木霉对营养的需求并不十分严格,可以分解利用纤维素、半纤维素、几丁质等多种多聚物作为其生长的碳源物质,也可以利用多种简单的和复杂的氮源化合物生长。为了应用木霉防治真菌病害,研究者摸索了各种培养条件,以求在低成本的前提下获得高的培养产物。其中包括应用糖蜜、麦麸、植物秸杆、虫草头孢废液和玉米粉等进行的固体培养、液体培养和固液两相培养,为大规模工业化生产奠定了一定的基础。     

放线菌327~#代谢产物对木酶的抑制作用

为探索利用拮抗菌防治由木霉引起的食用菌病害,以对多种植物病原菌有抑制作用的放线菌327#为供试材料,研究其对木霉的抑制效果和作用方式,以及对白灵菇生长的影响。结果表明:放线菌327#无菌发酵滤液对木霉菌丝生长有较强的抑制作用,培养7d,含327#发酵滤液的琼脂周围木霉无法生长。琼脂扩散试验中,发酵滤液在含木霉孢子的平板上可形成直径(20±1)mm的抑菌圈,圈内木霉孢子萌发受到强烈抑制。浓度为10%的发酵滤液使木霉菌丝停止发育,不能形成孢子。而327#发酵滤液对白灵菇的生长影响较弱,培养7d,含327#滤液的琼脂周围白灵菇可生长。由此可见,拮抗放线菌327#的代谢产物对木霉有较强抑制作用,而对白灵菇的影响不大。     

防治油菜菌核病的木霉和粘帚霉菌株筛选及生防的初报

2002年6月至12月中旬,用4批共200颗菌核作诱饵,分离到粘帚霉(Gliocladiumspp.)、木霉(Trichoderma spp.)、镰刀菌(Fusariumspp.)、青霉(Penicilliumspp.)、毛霉(Mucorspp.)、根霉(Rhizopusspp.)、曲霉(Aspergillus spp.)、腐霉(Pythiumspp.)和少量难鉴定菌株,共计171个菌株,其中粘帚霉80株、木霉55株,分别占46.8%和32.2%,在不同采样期内均为优势种群。所诱捕的木霉经鉴定分为7个种,哈茨木霉和康氏木霉出现较早,而黄绿木霉和拟康氏木霉出现较迟。通过测定所获得木霉菌株对核盘菌的拮抗作用,筛选出Tk1、Th2生防潜能较好的菌株。经离体叶片测定,Tk1和Th2对油菜菌核病的防治效果分别达90.6%和89.1%。     

根结线虫生防木霉菌菌株Snef85生物学特性初步研究

木霉菌菌株Snef85是一株分离于土壤、对根结线虫有较高毒力作用的生防菌,在原液(1×),5×,10×,15×和20×稀释液浓度下,二龄幼虫的校正死亡率分别是98.12%,93.21%,59.56%,41.66%,13.85%。对其生物学特性进行研究,结果表明,该菌以PDA培养基生长最适;以葡萄糖为最佳碳源;以丙氨酸为最佳氮源;菌丝最适生长温度范围在25~30℃;最适pH为5.0~6.0;光照对菌丝生长和孢子着生影响不明显。     

一株生防木霉菌的农药降解特性

从实验室保存的9株生防木霉菌中筛选出一株具有农药降解作用的木霉菌株Q3,该菌能够以100 mg/L高效氯氰菊酯、毒死蜱和吡虫啉为唯一碳源生长,7天的降解率分别达到90.43%、86.71%和78.81%;采用蔬菜大棚田间试验方法并利用气相色谱仪检测了高效氯氰菊酯和毒死蜱在油菜中的残留动态。结果表明,木霉菌Q3能够显著降低油菜中的农药残留,17天后高效氯氰菊酯和毒死蜱的降解率分别达到45.54%和72.58%。     

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

Though there are successful commercial biocontrol products with Trichoderma spp. in many countries including US, Israel and Europe, their usefulness is limited in cold environments such as mid-and northern part of Europe, US and Canada, especially in the late fall, winter and early spring period.Trichoderma isolates capable of growing at low temperatures (5-10℃) and showing good antagonistic properties against plant pathogenic fungi may have therefore both scientific and commercial value.     

Are mycoparasitism and chitinase production species or isolate dependent in Trichoderma ?

The relationship between taxonomic status of Trichoderma spp., chitinase production in solid substrate fermentation (SSF) on four media and mycoparasitism in dual culture (confrontation assay)against four plant pathogenic fungi was studied. Seventy five Trichoderma isolates belonging to 35species have been screened. The plant pathogenic fungi used in confrontation assay were Botrytis cinerea , Fusarium oxysporum f. sp. dianthi , Rhizoctonia solani and Sclerotinia sclerotiorum . The SSF media contained wheat bran, crude chitin (from crab shells, SIGMA) and salt solutions. The best performing isolates in mycoparasitism tests were Trichoderma flavofuscum, T. harzianum, T.inhamatum, T. koningii and T. strigosum. Some isolates exhibiting good mycoparasitism produced chitinase in SSF only at low or medium level. In contrary there were isolates with excellent extracellular chitinase production but their biocontrol potential did not belong to the leading group.Statistical methods have been used to evaluate the data.……     

木霉生防菌对大豆幼苗的促生作用及对根腐病的防治效果

[目的]研究木霉菌对大豆幼苗的促生作用及对根腐病的防治效果。[方法]用6株木霉菌剂处理土壤进行盆栽试验,测定大豆植株的形态指标及根腐病的发生情况。[结果]供试木霉菌株均能促进大豆植株生长,其株高、茎粗、根长、干物质积累均比对照增加。木霉菌株制剂均可减轻根腐病的发生,当浓度为5×108个/g时,防效均在70%以上。不同菌株对大豆植株的促生和对根腐病的防治效果不同。[结论]木霉菌能促进大豆的生长和降低根腐病的发生。     

木霉菌对番茄灰霉病菌的抑制作用

为明确木霉菌对福建省番茄灰霉病菌的抑制效果,研究了8株木霉菌对病原菌的拮抗作用。结果表明,在对峙培养条件下,供试木霉菌能显著抑制灰霉病菌菌丝生长,其抑制率为86.83%~91.39%,不同木霉菌株的发酵液对病原菌菌丝生长具有不同程度的抑制效果,其差异达显著水平。其中,菌株FJ2006-8发酵液的抑制生长率最高,为39.44%。此外,供试的木霉菌均能产生非挥发性和挥发性代谢产物,其中,菌株FJ2006-8的非挥发性代谢产物对病原菌菌丝生长的抑制效果最佳,抑制率为61.09%;而菌株T05-58的挥发性代谢产物对病原菌菌丝生长的抑制率最高,为22.95%。研究结果可为木霉菌生防菌剂的开发以及番茄灰霉病的绿色防控提供理论依据。     

哈茨木霉(Trichoerma harzianum)T23生防菌筛选及防治中药材根腐病的研究

研究表明,引起麦冬、丹参、川芎等中药材根腐病的主要病原种群是尖孢镰刀菌及腐皮镰刀菌．为了有效防治中药材根腐病,保护环境,提高品质和产量,通过不同生态区的土样采集,采取病原菌诱饵法及稀释平扳法分离菌株,经筛选、纯化得到抑菌拮抗效果达80％以上的哈茨木霉生防菌T23;不同剂量试验结果表明,施用哈茨木霉T23生物制剂7．5kg／hm^2效果最佳,田间防治麦冬、丹参、川芎等中药材根腐病效果达70％以上,显著优于50％多菌灵粉剂,比对照增产14．2％～24．5％．大面积防治中药材根腐病的防病增产效果与田间小区试验的一致．     

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 …     

Screening of Trichoderma strains tolerant to benzimidazole

The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were purified, and their physical and chemical properties were detected. Compared their biological activities in vitro and vivo in greenhouse, nine biocontrol strains (including Ty-10-2,LTR-2,Tj-5-1,Tj-5-4,Ty-11-1,Tj-11-3,Ty-11-3,Tj-3-3-2,Tj-3-3-4) were screened. These bioco…     

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 laborator…     

土壤中木霉的分离纯化以及对植物病原真菌的拮抗研究

从土壤中分离纯化获得3个木霉集合种:哈茨木霉(Trichoderma harzianum),绿色木霉(Trichoder-ma viride)和绿木霉(Trichoderma virens)。用这3种木霉菌分别与小麦纹枯病菌(Rhizoctonia solania)和番茄灰霉病菌(Botrytis cinerea)作平板对峙培养及显微观察,测定木霉菌对病原菌的抑制作用。结果表明:3种木霉菌对供试的2种病原菌抑菌强度不同,其中绿木霉对小麦纹枯病菌和番茄灰霉病菌都具有较好的拮抗作用;显微观察到木霉菌对病原菌菌丝的缠绕、使病原菌菌丝细胞质变稀薄、菌丝解体等现象。     

Applications of Trichoderma formulations in crop protection

The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic cap…     

木霉与土壤生态环境关系研究综述

木霉是土壤真菌中的重要群落,在植物根际分布非常广泛,是一种很有应用价值的植物生防菌。从土壤生态环境对木霉的影响和木霉对土壤的修复作用,对木霉与土壤生态环境的关系展开论述,并对土壤木霉的应用进行了展望。     

木霉对食用菌侵染能力的分析

研究了49株木霉对食用菌菌丝的侵染能力,结果显示:不同木霉的侵染能力不同,对食用菌侵染能力强的木霉对植物病原真菌的侵染能力并不一定强,表现出木霉对真菌侵染的特异性。木霉侵染食用菌的机理研究结果显示:木霉可通过溶壁、缠绕等方式作用于食用菌菌丝细胞壁,木霉发酵液对食用菌和植物病原菌都有很好的抑制作用,但木霉产几丁质酶的能力与木霉的侵染能力没有直接关系。     

黄绿木霉T1010适宜的发酵条件分析

木霉广泛存在于土壤、根际及其它基质中,木霉对植物土传病具有拮抗作用.优化生防因子黄绿木霉(Trichoderma aureoviride)突变体T1010发酵条件是扩大生产、大面积应用的前提.试验通过测定黄绿木霉T1010的菌丝生长和分生孢子生长,优化了培养条件,确定最适宜种子培养用PD培养基,摇瓶培养,生长时间为3天,此时菌丝生长量为5.75 g/ml;最经济适宜扩大培养基为玉米15 g/L,豆粉5 g/L,摇瓶培养时间为3天,此时菌丝生长量为5.83 g/ml,发酵罐培养时间2.5天为宜;最适宜经济的固体发酵培养基为麦麸:醋渣∶水=2∶1∶3.3,尿素为0.3%,发酵温度为(26±2)℃,发酵产物孢子量为2.46×1010cfu/g.通过该研究确定的发酵工艺参数为高效率、低成本、标准化生产黄绿木霉制剂提供了科学依据.     

Genetic regulation of conidiation in Trichoderma hamatun

Achieving a balance between vegetative growth and spore production is essential for successful biocontrol by fungi. Low sporulation rates in the field can result in poor establishment and survival,whereas failure of conidia to recognise hosts can lead to persistence without efficacy. Commercial biocontrol products involve bulk preparations of conidia, however considerable variability in conidiation rates exists between biocontrol agents, which can restrict choice of strain for production. The majority of studies on Trichoderma conidiation have focused on the species T. viride and T. atroviride.These species form conidia in response to blue and near-UV light and/or nutrient deprivation and conidiation proceeds in a highly co-ordinated fashion, however relatively little is known on the genetic basis of Trichoderrma conidiation. In addition, whilst photoconidiation appears to be a general response detailed studies in other Trichoderma species are absent. In this study, conidiation in the lesser known biocontrol species T. hamatum is being investigated using a combined morphological and molecular approach. In contrast to T. atroviride, conidiation in response to blue-light was weaker and variable and suggested that additional triggers may be required for the T. hamatum photoresponse. A series of comparative photoconidiation assays are currently being undertaken investigating the effect of inoculum type and abiotic factors on timing and intensity of the response.Results will be discussed in relation to the current knowledge on conidial morphogenesis in Trichoderma. In addition to these morphological assays, a selection of genes implicated in sporulation and the blue-light responses are currently being isolated and characterised from T. hamatum. Two genes, phr1 and cmp1 , which were isolated previously from T. atroviride will be used as early and late markers of gene expression during the photoresponse in T. hamatum in order to define time points for harvesting comparable stage-specific RNA from T. hamatum and T. atroviride. Using degenerate PCR putative sporulation gene orthologues have also been identified in T. hamatum.Work is currently underway to isolate genomic clones of these genes from T. hamatum and T.atroviride. Sequence and expression analysis of orthologues, including expression in response to abiotic factors will be presented and discussed in relation to the current knowledge of the molecular basis of conidiation in Trichoderma and other filamentous fungi.……