Study of signal transduction factors involved in mycoparasitic response of Trichoderma atroviride

Numerous Trichoderma spp. are mycoparasites and commercially applied as biological control agents against a large number of plant pathogenic fungi. The mycoparasitic interaction is host-specific and several research strategies have been applied to identify the main genes and compounds involved in the antagonist-plant-pathogen three-way interaction. During mycoparasitism, signals from the host fungus are recognised by Trichoderma, stimulating antifungal activities that are accompanied by mo…     

Genetic improvement of Trichoderma ability to induce systemic resistance

The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not comple…     

Soil tillage methods by years interaction for dry matter of plant yield of maize (Zea mays L.) using additive main effects and multiplicative interaction model

The objective of this study was to assess soil tillage methods by years interaction for dry matter of plant yield of maize(Zea mays L.) grown in West Poland by the additive main effects and multiplicative interaction model. The study comprised four soil tillage methods, analysed in 12 years through field trials arranged in a randomized complete block design, with four replicates. Dry matter of plant yield of the tested soil tillage methods varied from 86.7 dt ha~(–1)(for no-plough tillage in 2005) to 246.4 dt ha~(–1)(for complete conventional tillage in 2012), with an average of 146.6 dt ha~(–1). In the variance analysis, 49.07% of the total dry matter of plant yield variation was explained by years, 12.69% by differences between soil tillage methods, and 10.53% by soil tillage methods by years interaction. Dry matter of plant yield is highly influenced by soil tillage methods by years factors.     

A New Method to Determine Central Wavelength and Optimal Bandwidth for Predicting Plant Nitrogen Uptake in Winter Wheat

Plant nitrogen(N) uptake is a good indicator of crop N status.In this study,a new method was designed to determine the central wavelength,optimal bandwidth and vegetation indices for predicting plant N uptake(g N m-2) in winter wheat(Triticum aestivum L.).The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years,eco-sites,varieties,N rates,sowing dates,and densities.The plant N uptake index(PNUI) based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index,and a linear model was developed with R2 of 0.870 and RMSE of 1.546 g N m-2 for calibration,and R2 of 0.834,RMSE of 1.316 g N m-2,slope of 0.934,and intercept of 0.001 for validation.Then,the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion.The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index.These findings are important for prediction and diagnosis of plant N uptake more precise and accurate in crop management.     

Physiological mechanisms involved in resistance to cotton verticillium wilt induced by AM fungi

It was proved that arbuscular mycorrhizal (AM) fungi played an important role in increasing plant resistance to soilborne pathogens, especially when plants were pre-inoculated with AM fungi. Mechanisms involved in this phenomenon are not yet well understood. On the basis of the former experiment results in our lab, effects of AM fungi on cotton Verticillium wilt and the mechanisms of increasing disease resisitance by the tested fungi were studied in pot culture under greenhouse conditions. …     

Identification of Zinc Deficiency-Responsive MicroRNAs in Brassica juncea Roots by Small RNA Sequencing

The importance of zinc （Zn） as a micronutrient essential for plant growth and development is becoming increasingly apparent. Much of the world’s soil is Zn-deficient, and soil-based Zn deficiency is often accompanied by Zn deficiency in human populations. MicroRNAs （miRNAs） play important roles in the regulation of plant gene expression at the level of translation. Many miRNAs involved in the modulation of heavy metal toxicity responses in plants have been identiifed;however, the role of miRNAs in the plant Zn deifciency response is almost completely unknown. Using high-throughput Solexa sequencing, we identiifed several miRNAs that respond to Zn deifciency in Brassica juncea roots. At least 21 conserved candidate miRNA families, and 101 individual members within those families, were identiifed in both the control and the Zn-deifcient B. juncea roots. Among this, 15 miRNAs from 9 miRNA families were differentially expressed in the control and Zn-deifcient plants. Of the 15 differentially expressed miRNAs, 13 were up-regulated in the Zn-deifcient B. juncea roots, and only two, miR399b and miR845a, were down-regulated. Bioinformatics analysis indicated that these miRNAs were involved in modulating phytohormone response, plant growth and development, and abiotic stress responses in B. juncea roots. These data help to lay the foundation for further understanding of miRNA function in the regulation of the plant Zn deifciency response and its impact on plant growth and development.     

Advances on the Molecular Mechanism of the Interaction between Ralstonia solanacearum and Hosts

Ralstonia solanacearum is an important model phytopathogenic bacterium that causes bacterial wilt disease on many plant species and leads to serious economic losses. The interactions between R. solanacearum and host plants have become a model system for the study of plants and pathogens interactions. This paper reviews the advances on the molecular mechanisms between R. solanacearum and hosts interaction including the formation of plant innate immunity, the suppression of plant innate immunity by this pathogen and the activation of effector-triggered immunity. Furthermore, we made a prospect on how to utilize the interaction mechanism between R. solanacearum and hosts to control the disease.     

Polymorphism and association analysis of a drought-resistant gene TaLTP-s in wheat

Lipid transfer protein(LTP) is a kind of small molecular protein, which is named for its ability to transfer lipid between cell membranes. It has been proved that the protein is involved in the responding to abiotic stresses. In this study, Ta LTP-s, a genomic sequence of TaLTP was isolated from A genome of wheat(Triticum aestivum L). Sequencing analysis exhibited that there was no diversity in the coding region of Ta LTP-s, but seven single nucleotide polymorphisms(SNPs) and 1 bp insertion/deletion(In Del) were detected in the promoter regions of different wheat accessions. Nucleotide diversity(π) in the region was 0.00033, and linkage disequilibrium(LD) extended over almost the entire Ta LTP-s region in wheat. The d CAPS markers based on sequence variations in the promoter regions(SNP-207 and SNP-1696) were developed, and three haplotypes were identified based on those markers. Association analysis between the haplotypes and agronomic traits of natural population consisted of 262 accessions showed that three haplotypes of Ta LTP-s were significantly associated with plant height(PH). Among the three haplotypes, Hap III is considered as the superior haplotype for increasing plant height in the drought stress environments. The G variance at the position of 207 bp could be a superior allele that significantly increased number of spikes per plant(NSP). The functional marker of Ta LTP-s provide a tool for marker-assisted selection regarding to plant height and number of spikelet per plant in wheat.     

Extracellular proteome of Trichoderma harzianum to identify proteins with biotechnological value

Trichoderma harzianum strain T22 parasitizes and controls many phytopatogenic fungi and is applied commercially as biological control agent. The production of hydrolitic enzymes appears to be a key factor in the parasitic process. We tested the endo-esochitinolitic and glucanolitic activities of culture filtrates of T22 grown under carbon and nitrogen starvation or in presence of biomass or cell walls of the phytopathogenic fungi Botrytis cinerea, Rhizoctonia solani and Pythium ultimum. …     

Effect of rare earth application on the growth of Trichoderma spp. and several plant pathogenic fungi

Rare earth elements (REEs) enriched fertilisers are currently used in China for soil and foliar applications to crops, but little is known about the effect of REEs applications on the growth of beneficial and detrimental soilborne microorganisms. The growth of biological control agents Trichoderma atroviride strain P1, Trichoderma harzianum strain A6 and strain T22, plant pathogens Botrytis cinerea, Alternaria alternata, Fusarium solani, Rhizoctonia solani and Sclerotinia scleroti…     

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 p…     

Use of Hypocrea jecorina (anamorph Trichoderma reesei) as a model system for Trichoderma biocontrol of Pythium blight identifies new targets for genetic strain improvement

Biocontrol by Trichoderma has been studied mainly with selected isolates of T. harzianum, T. atroviride and T. asperellum, which are members of sections Pachybasium and Trichoderma. In contrast, species from section Longibrachiatum have only rarely been studied. On the other hand, one taxon from this section-Hypocrea jecorina (anamorph: Trichoderma reesei)-has been widely used for the production of cellulolytic and hemicellulolytic enzymes and recombinant proteins. As far as T…     

木霉菌对五种植物病原真菌的重寄生作用

研究了哈茨木霉（Trichoderma harzianum)T88菌株和深绿木霉（T.atroviride）T95菌株对立枯丝核菌（Rhizoctonia solani）、杨树料皮病菌（Valsa sordida）、杨树水泡溃疡病菌（Botryosphaeria ribis）、苹果树腐烂病菌（V.ceratosperma）、贝伦格葡萄座腔菌梨生专化型（B.berengeriana f.sp.piricola）的重寄生作用。对峙培养的结果可观察到，多数情况下，接种后2d内木霉与病原菌接触，随后覆盖或侵入病菌菌落，抑制其生长。光学显微镜和扫描电镜观察结果表明，木霉对不同的植物病原真菌重寄生作用方法不同。可观察到木霉菌缠绕病原菌的菌丝，或沿着病原菌的菌丝平行或波浪式生长，或产生铯状分枝、吸器或附着胞吸附于病原菌的菌丝上，或穿透病原菌的菌丝，最终使病原菌的菌丝细胞原生质浓缩，菌丝断裂等现象。     

5个木霉菌株的抑菌谱及部分生物学特性

 5个木霉菌株在对峙培养中对水稻稻瘟病菌、水稻纹枯病菌、棉花枯萎病菌、油菜菌核病菌等18种植物病原真菌和7株土壤习居镰刀菌都有明显抑制效果。哈茨木霉菌株Th-B的抑菌效果显著高于绿色木霉菌株LTR-2和其他3个菌株,哈茨木霉菌株Th-A和Th-B的产孢能力高于其他菌株,Th-B对辣椒灰霉病的预防效果达65.20%.     

Proteomics related to the biocontrol of Pythium damping off in maize with Trichoderma harzianum

Trichoderma harzianum strain T22 controls various diseases of maize and other crops, including seedling and root rots caused by Pythium ultimum. Seedlings of inbred line Mo17 were grown from T22-treated or untreated seeds in field soil or in field soil intested with the pathogen. Five days after planting, seedlings of Mo17 (5-days-old) were smaller in the presence of P. ultimum and larger in the presence of T22 relative to the control. The combination of T22 with P. ultimum (T22 P.…     

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。     

木霉菌对灰葡萄孢菌的拮抗作用

对采自宁夏14个市县的170份土样及其它材料进行分离,得到96个木霉菌株,采用形态分类方法鉴定出9种木霉菌以及2种未知名菌种．它们分别为哈茨木霉（Trichoderma harzianum）、绿色木霉（T．viride）、长枝木霉（T．longibrachiatum）、康氏木霉（T．koningii）、拟康氏木霉（T．pseudokoningii）、项孢木霉（T．fertile）、黄绿木霉（T．aureoviride）、深绿木霉（T．atroviride）、钩状木霉（T．hamatum）以及T．sp1和T．sp2。拮抗作用和抑菌活性测定结果表明：11种木霉菌对葡萄、番茄和黄瓜灰霉病的致病菌——灰葡萄孢菌（Botrytis cinema Petssp．）均有不同程度的拮抗作用,其中哈茨木霉、绿色木霉、黄绿木霉、钩状木霉和T．sp1对病原菌的拮抗作用及抑菌活性显著,其生长速度比病原菌平均快1．1～3．0倍：在对峙培养中拮抗系数达Ⅰ级或Ⅱ级．其抑菌率高迭98．78％。