拮抗北细辛菌核病木霉菌的分离、鉴定及生防效果

【背景】菌核病是北细辛根部主要病害之一,木霉菌作为目前应用最广泛的生物防治真菌,利用木霉菌防治北细辛菌核病是目前研究的热点。【目的】通过稀释分离法对健康北细辛植株根际土壤进行菌株分离,以期筛选出有效拮抗北细辛菌核病的生防木霉菌。【方法】以北细辛菌核病菌为靶标菌,采用平板对峙培养、挥发性与非挥发性物质抑菌的方法对分离得到的木霉菌进行筛选,采用生长速率法对筛选出的木霉菌的发酵液进行抑菌效果测定,并采用硫代巴比妥酸法测定筛选出的木霉对北细辛菌核病菌的丙二醛(Malondialdehyde,MDA)含量、紫外吸收法测定过氧化氢酶(Catalase,CAT)活性、氮蓝四唑法测定超氧化物歧化酶(Superoxide Dismutase,SOD)活性、愈创木酚法测定过氧化物酶(Peroxidase,POD)活性的影响。【结果】从土壤中分离出木霉菌共14株,通过形态学和ITS-RPB2双基因联合构建系统发育树,鉴定其为哈茨木霉(Trichoderma harzianum)、钩状木霉(Trichoderma hamatum)、拟康氏木霉(Trichoderma koningiopsis)、深绿木霉(Tr...     

防治平贝母菌核病的木霉菌筛选及室内防效

【背景】由病原菌Sclerotium denigrans侵染引起的平贝母菌核病是其主要的鳞茎病害之一,给平贝母种植产业带来了巨大的损失。【目的】筛选出对平贝母菌核病具有拮抗效果的木霉菌株。【方法】以平贝母菌核病作为靶标菌,采用平板对峙试验、平板对扣法、圆盘滤膜法与发酵液抑菌试验筛选对平贝母菌核病具有拮抗效果的木霉菌株。采用顶空固相微萃取的方法检测拮抗效果较好的木霉菌挥发性成分;二硝基水杨酸(dinitrosalicylic acid, DNS)比色法测定木霉菌的β-1,3葡聚糖酶的活性;室内防效试验验证其对平贝母菌核病的防治效果。【结果】平板对峙试验发现木霉菌F1、F2和D6对平贝母菌核病菌的生长具有较强的抑制作用,其抑菌率分别为91.06%、87.00%和86.12%;平板对扣法发现木霉菌E17和A26对菌核病菌的抑制效果最为明显,抑菌率分别为74.96%和75.86%;圆盘滤膜法发现菌核病菌在F2、C6、D3、F4、A26、B30、D4和D6的琼脂培养基上均不生长,抑菌率达100%;发酵液抑菌试验表明木霉菌D3抑制效果最强,可完全抑制菌核病菌的生长,抑菌率为100%;对A26、D4、E8、E17和D3这5株木霉进行GC/MS挥发性产物分析,在E17发现了具有抗真菌活性的6-戊基-2H-吡喃-2-酮等活性物质;DNS比色法发现β-1,3葡聚糖酶活性最高的木霉菌为F1;室内防效试验测定发现D3能明显抑制平贝母鳞茎菌核病的病变,对平贝母菌核病具有潜在的生防活性。【结论】木霉菌D3在防治平贝母菌核病中是极具开发价值的菌种。     

木霉菌生态学及其在生防中的应用

本文就木霉菌生物学和生态学的研究进展作一评述,简要概述了木霉菌在土壤、植物地上部分和植物病害综合防治方面的应用,提出了今后该领域的研究方向。     

生防木霉菌产几丁质酶特性研究

通过采取还原糖法对生防木霉菌真菌2号和真菌4号菌株在不同发酵时间产几丁质酶活性进行测定,并对几丁质酶特性进行初步研究.试验结果表明,同一菌株在不同发酵时间几丁质酶活性大小变化的趋势大致相同,真菌4号在培养145 h几丁质酶活性达到最大,真菌2号在培养170 h几丁质酶活性达到最大.在相同发酵时间,真菌4号菌株的几丁质酶活性比真菌2号菌株的几丁质酶活性要高.     

马铃薯种质资源的晚疫病抗性鉴定

采用离体叶片接种法,对43份马铃薯种质资源进行晚疫病抗性鉴定、比较和评价。以接种5 d后的感病品种‘Désirée’和抗病品种‘加湘1号’叶片症状为对照,鉴定出5份表现为高抗的种质资源,其中包含3个Solanum phurejia和2个S. tuberosum ssp. andigena材料。另外,还鉴定出14份中抗材料(No. 7～20)。结果表明,野生种和安第斯山栽培亚种马铃薯资源的抗性材料较为丰富,可作为晚疫病抗病育种的亲本。     

粮食上木霉菌的分离鉴定及其生防效果

【背景】粮食在生长和收储期极易受到病原真菌或产毒真菌的污染,造成严重的损失。众多实践证明木霉属(Trichoderma)可以有效防治植物病原真菌。【目的】鉴定和筛选能有效抑制粮食常见危害真菌的木霉生防菌株,开发生防菌剂,保障粮食生产安全。【方法】从粮食上分离筛选出35株木霉,通过多基因系统发育分析和形态学观察方法进行菌种鉴定,利用平板对峙试验筛选出对粮食常见危害真菌有抑制作用的菌株。【结果】35株木霉分属于8个种,分别为非洲哈茨木霉(Trichodermaafroharzianum)、类棘孢木霉(Trichodermaasperelloides)、 Trichoderma amoenum、近深绿木霉(Trichoderma paratroviride)、Trichoderma obovatum、长枝木霉(Trichoderma longibrachiatum)、东方木霉(Trichodermaorientale)和深绿木霉(Trichodermaatroviride)。对峙试验结果表明,这8种木霉对于粮食上分离到的10种危害真菌均具有较好的抑制效果。非洲哈茨木霉(T.afroharzi...     

生防木霉菌原生质体的制备及再生研究

ACCC 30150是由本实验室筛选的一株对黄瓜枯萎病、青椒疫病等多种土传病害具有较好防治效果的生防木霉菌.为了建立该生防木霉菌的CaCl2/PEG转化体系,对其原生质体制备及再生条件进行了摸索.结果表明,以0.6 M NaCl作为渗透压稳定剂,用PDA平板上培养36 h的微小菌丝接种液体菌丝培养基,菌龄16 h,用20 mg/ml的纤维素酶和蜗牛酶以1:1的比例混合,按照菌丝重量(g):酶液体积(ml)=1:20的比例,36℃酶解2 h原生质体产量最高.同时,酶解2 h,以CMR1为再生培养基原生质体的再生率最高.     

生防木霉菌β-1,3-葡聚糖酶活性研究

通过采取还原糖法对生防木霉菌真菌2号和真菌4号菌株在不同发酵时间产β-1,3-葡聚糖酶活性进行测定,对其产β-1,3-葡聚糖酶特性进行初步研究。结果表明,同一菌株在不同发酵时间β-1,3-葡聚糖酶活性大小变化的趋势大致相同,并均在培养72 h时β-1,3-葡聚糖酶活性达到最大,在相同发酵时间,真菌2号菌株比真菌4号菌株的β-1,3-葡聚糖酶活性要高。     

利用马铃薯晚疫病菌粗毒素离体筛选马铃薯抗晚疫病无性系

以3个马铃薯品种叶片外植体的愈伤组织为材料、马铃薯晚疫病病菌培养粗毒素为筛选压力进行马铃薯抗晚疫病细胞变异无性系筛选。结果表明,不同品种的叶片、愈伤组织对毒素有不同的忍耐力。“费乌瑞它”最大忍耐的粗毒素浓度为40％,“东农303”、“早大白”则为50％。马铃薯晚疫病病原菌粗毒素对愈伤组织的诱导、生长、不定芽的分化及再生苗生根有显著的抑制作用,而且浓度越大,抑制作用越强。筛选结果抗性鉴定表明,经过粗毒素筛选的细胞无性系及其再生植株对高浓度粗毒素的抗性能力显著高于对照。     

木霉菌与种子生物处理

本文从木霉菌的生防特性出发,论述了木霉菌在种子生物处理方面的应用潜力和研究进展,并对今后工业化生产的若干途径进行了比较。     

Biological spectrum of Trichoderma harzianum Rifai isolates to control fungal diseases of tomato (Solanum lycopersicon L.)

Three Trichoderma harzianum isolates viz., Th-Sks, Th-Ke and Th-Ar collected from respective states of India viz., Rajasthan, Kerala and Andhra Pradesh were evaluated for the management of six fungal diseases namely damping off, Fusarium wilt, Rhizoctonia wilt, early leaf spot, late blight and Septoria leaf spot in tomato. During in vitro analysis, T. harzianum isolates inhibited the pathogens’ growth. Isolate Th-Sks was the most virulent antagonist against all the test pathogens and exhibited maximum of 79.47% growth inhibition of Phytophthora infestans. Isolate Th-Sks proved most effective at suppression efficacy in the range of 95–100% and 91–100% against all diseases under glasshouse and in the field conditions, respectively. Tomato seeds treatment with isolate Th-Sks also promoted plant height (78.23 cm) and fruits yield (290 g/plant) during field trial and data were found to be not-significantly different from other isolates. Thus, it is concluded that isolate Th-Sks can be utilised as a biocontrol agent for management of fungal diseases in tomato.     

Genotypic Analysis of Russian Isolates of Phytophthora infestans from the Moscow Region, Siberia and Far East

Phytophthora infestans samples were collected during 1997 and 1998 at multiple sites in Russia from Sakhalin Island in the Far East across Siberia (nine sites, 160 isolates) to the Moscow region (four sites, 325 isolates). In addition, 12 isolates that were obtained previously were included. All isolates were analysed for mating type, and sensitivity to metalaxyl. Isolates from within any of the nine sites outside of the Moscow region were monomorphic for mating type and nearly monomorphic for metalaxyl resistance. In contrast, both A1 and A2 isolates were detected in the Moscow region, and these isolates were also polymorphic for metalaxyl resistance. In two sites in Siberia only A2 mating type strains were detected, in the other six sites in Siberia and in Sakahlin Island, only A1 mating types were detected. A subset of isolates ( n =191) was also analysed for pathotype (virulence to 10 R-genes, each in a distinct differential genotype). All isolates were highly complex (mean number of virulences approximately 8.4 of a maximum number of 10). All isolates ( n =43) from Sakahlin Island were virulent to all 10 of the R-genes tested. A further subset of isolates ( n =70, including 12 isolates collected before 1997) was analysed for genotype at the Glucose- 6-phosphate isomerase and Peptidase loci, mtDNA haplotypes, and RFLP pattern using the RG57 probe. The US-1 clonal lineage (previously dominant) was not detected in the 1997–98 sample. The populations of P. infestans near Moscow in 1997 and 1998 was highly diverse with 15 unique genotypes (including both mating types) among a sample of 18 isolates. In contrast, the populations of P. infestans in Siberia had limited diversity, with only three multilocus genotypes detected and most populations were dominated by the SIB-1 clonal lineage. This lineage accounted for 31 of the 39 strains collected in Siberia that were assayed for multilocus genotype.     

基于高通量测序的福建北部马铃薯晚疫病株根际土壤细菌群落分析

[背景]马铃薯晚疫病是一种由致病疫霉[Phytophthora infestans(Mont.)de Bary]引起的毁灭性病害,当环境条件适宜时,残留在土壤中的病原菌会侵染马铃薯植株导致病害的发生.[目的]明确健康马铃薯植株与发病植株的根际土壤细菌结构与多样性.[方法]采集马铃薯晚疫病发病地的健康植株根际土壤(M2J...     

Effect of Pathogen Isolate, Potato Cultivar, and Antagonist Strain on Potato Scab Severity and Biological Control

Antibiotic-producing Streptomyces spp. have shown potential in biocontrol of potato scab caused by Streptomyces scabies. However, results have been inconsistent among field trials. Pathogen isolate, antagonist strain and potato cultivar were investigated as potential sources of variation in the efficacy of potato scab biocontrol. Biocontrol success varied significantly among pathogen isolates and was not correlated with in vitro sensitivity to antibiotic inhibition. Antagonists also varied in their effectiveness as biocontrol agents, and the relative effectiveness of different antagonists varied among growing seasons. Finally, biocontrol varied among potato cultivars in the field. The diverse origins of significant variation in potato scab biocontrol suggest that consistent control in the field is likely to be difficult to achieve.     

Oospore Germination and Formation by the Late Blight Pathogen Phytophthora infestans in vitro and under Field Conditions

The ability of the late blight pathogen Phytophthora infestans to form oospores in leaves of seven potato cultivars was examined at different incubation temperatures under controlled environmental conditions and under field conditions. At 10°C, the oospore formation in three intermediate-resistant cultivars all differed significantly from each other (P < 0.05), with the lowest amount formed in cv. Asterix. This latter cultivar did not form oospores at any other temperature. Under field conditions oospores were formed abundantly in a naturally infected field. A significant date by cultivar interaction showed that P. infestans increased the oospore formation in foliage by time in cvs Columbo, Hertha and Matilda, whereas no significant differences between dates were found for other cultivars. The genetic structure of P. infestans in the naturally infected field plot, where oospores formed abundantly, was studied by using amplified fragment length polymorphism and a high genetic diversity was revealed. Oospore germination from two Scandinavian (A1 and A2) P. infestans isolates was stimulated in visible light and in 1 : 2 and 1 : 10 soil extract. The effect of light and nutrients on oosporogenesis is discussed.     

马铃薯晚疫病菌卵孢子萌发的初步研究

描述了马铃薯晚疫病菌卵孢子萌发的方式并研究了菌株组合、卵孢子形成时间、在琼脂培养基上培养时间及光照对卵孢子萌发的影响,结果表明不同菌株组合卵孢子萌发率为0—7.2%,对峙培养20天后形成的卵孢子的萌发率最高达8.7%,在琼脂培养基上培养25-30d 萌发率最高达11.4%,卵孢子形成时黑暗及在琼脂培养基上萌发时光照萌发率最高达11.8%。     

Potential for Biocontrol of Lasiodiplodia theobromae (Pat.) Griff. & Maubl. in Banana Fruits by Trichoderma Species

Fifteen Trichoderma isolates were tested for their antagonistic ability against Lasiodiplodia theobromae. Trichoderma harzianum exhibited the greatest inhibition in dual culture. Microscopic investigation demonstrated direct parasitism and coiling of T. harzianum and T. viride around hyphae of L. theobromae, causing swollen, deformed, shortened, or rounded cells of the pathogen. Granulation of cytoplasm and disintegration of the hyphal walls of L. theobromae also were noted in dual culture. Trichoderma viride reduced rotting by 29.07 to 65.06% in artificially inoculated banana fruits. Treatment of banana fruits with T. viride 4 h prior to inoculation with L. theobromae provided better protection than simultaneous application or treatment 4 h after inoculation.