The Beneficial Effect of Trichoderma spp. in Seed Treatment of Four Maize (Zea mays L.) Genotypes

Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 108 spores mL-1, using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4®. H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg);T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m2 of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.

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 spp.对樟子松枯梢病病原菌的影响

通过Trichoderma属 3个菌株与樟子松枯梢病菌 (Sphaeropsissapinea)对峙培养试验的结果表明 :Tri chodermaviride1,Trichodermaviride 2及Trichodermaharzianum对樟子松枯梢病病原菌都有抑制效果 ,其中Trichodermaviride 2对病原菌的相对抑制效果最好 ,且其相对抑制效果随着时间的增加而增长 ,在 4 0h达到最高 ,为 73.5 5。Trichodermaviride 1和Trichodermaharzianum对病原菌的相对抑制效果在 16h达到最高 ,分别为 4 .86及 2 .5 9。

木霉(Trichoderma spp.)对三种引起大棚蔬菜病害病原菌的影响

通过木霉属(Trichoderma) 3菌株与双鸭山蔬菜大棚中的黄瓜枯萎病菌(FusariumoxysporumSchlecht.f.cucumerinum)、黄瓜果腐病菌(PhytophthoracapsiciLeonian)、菜豆叶枯病菌(Cladosporiumsp .)的对峙培养试验,结果表明:绿色木霉1(TrichodermaviridePers.exGray 1)可作为双鸭山蔬菜大棚中的黄瓜枯萎病、黄瓜果腐病、菜豆叶枯病3种病害的生物防治拮抗菌加以利用,该拮抗菌对菜豆叶枯病菌抑制效果最好;绿色木霉2 (Tricho dermaviride 2 )对黄瓜果腐病菌抑制效果最好;而哈茨木霉(TrichodermaharzianumRifai)对以上3种病原菌都有抑制效果,对菜豆叶枯病菌抑制效果最好。从试验结果还可看出,绿色木霉2对黄瓜枯萎病菌和菜豆叶枯病菌的生长有促进作用。

具有生防能力的木霉菌(Trichoderma spp.)与两株大豆根腐病病原菌(Fusarium oxysporum、Rhizoctonia solani)对碳、磷、铁的竞争研究

通过室内试验研究比较了具有生物防治能力的5株木霉菌株与2株大豆根腐病病原菌(Fusarium oxysporum、Rhizoctonia solani)对C、P、Fe等营养元素的竞争。试验结果表明病原菌F.oxysporum利用葡萄糖的速度显著的高于所测试的木霉菌株(菌株MM9除外),而木霉菌株MM9、S7、SH7、S2利用葡萄糖的速率显著的高于病原菌R.solani。木霉菌株S7、S2利用可溶性磷的速率显著的高于病原菌F.oxysporum。木霉菌株MM35利用可利用铁的速率显著的高于病原菌(F.oxysporum、R.solani)。木霉菌与大豆根腐病病原菌(F.oxysporum、R.solani)对C、P、Fe营养的竞争呈现多样性。

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

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。

New advances in the science and use of Trichoderma spp.

Trichoderma spp. have been known for their strong abilities to produce extracellular enzymes, especially cellulases and glucanases by T. reesei, and also for their abilities to control plant pathogens. Most notably, a number of lines of evidence indicate that the agriculturally relevant strains are synergistic plant symbionts. As plant symbionts they possess the following characteristics: (a) they infect plant roots but cause the plant to restrict their growth to outer layers of the plant cortex (an exception is the recent discoveries of plant endophytic strains of Trichoderma and Gliocladium ), (b) they produce bioactive plant molecules in the zone of interaction that (c) induce localized systemic resistance to plant diseases and (d) systemic plant resistance to diseases that in some respects is similar to that induced by rhizobacteria, (e) they induce changes in plant proteomes, (f) increase plant growth and yield at least in part by enhancing root growth, and (g) they increase plant nutrient uptake. The increase in plant growth and yields is strongly interactive with plant genotype, at least in maize. There also are very significant increases in the knowledge of events that occur in mycoparasitism that in many respects have features in common with their interactions with plants. They are highly resistant to toxicants and have recently been shown to degrade cyanide and take up, and then degrade, metallocyanides. These discoveries allow new uses for the organisms in managed plant systems, including agriculture. For example, the induced systemic resistance system allows control of fungi, bacteria, Oomycetes and even one virus at sites temporally and spatially distant from the site of application. The abilities of the fungi to resist/degrade toxicants and increase plant growth indicate they will highly useful components in plant-microbe or microbe-only strategies for remediation of soil and water pollution. Finally, there are new uses of their enzyme systems for production of chitin degradation products for use as nutraceuticals or pharmaceuticals.

Trichoderma spp.and Bacillus spp.as growth promoters in maize(Zea mays L.)

Microbes that are beneficial to plants are used to enhance the crop growth,yield and are alternatives to chemical fertilizers.Trichoderma and Bacillus are the predominant plant growth-promoting fungi and bacteria.The objective of this study was select,characterize,and evaluate isolates of Trichoderma spp.and Bacillus spp.native from the northern region of Sinaloa,Mexico,and assess their effect on growth promotion in maize(Zea mays L.).In greenhouse conditions,four Trichoderma isolates and twenty Bacillus isolates,as well as two controls,were tested in a completely randomized design with three replicates.We selected the two best strains of Trichoderma and Bacillus:TB=Trichoderma asperellum,TF=Trichoderma virens,B14=Bacillus cereus sensu lato and B17=Bacillus cereus,which were evaluated in the field in a completely randomized blocks in factorial arrangement design with three replicates applying different rates of nitrogen fertilizer(0,150 kg N/ha,and 300 kg N/ha).Treatments 5(B17=B.cereus)and 11(TF=T.virens)both fertilized with 150 kg N/ha showed similar yields and they did not reveal significant differences from the treatments fertilized with 300 kg N/ha.This indicated that treatment 5(B17=B.cereus with 150 kg N/ha)and treatment 11(TF=T.virens with 150 kg N/ha)were efficient as growth promoters,by not showing significant differences in root volume and dry weight of foliage.The results indicated a reduction of 50% in the rate of nitrogen to fertilizer required for maize(Zea mays L.)crops.These microorganisms Trichoderma and Bacillus could be an alternative to reduce the use of chemical fertilizers in maize.

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).

基于改进YOLOv3-SPP算法的道路车辆检测

针对在城市道路场景下视觉检测车辆时,车辆密集和远处车辆呈现小尺度,导致出现检测精度低或者漏检的问题,提出了一种基于改进的YOLOv3-SPP算法,对激活函数进行优化,以DIOU-NMS Loss作为边界框损失函数,增强网络的表达能力。为提高所提算法对小目标和遮挡目标的特征提取能力,引入空洞卷积模块,增大目标的感受野。实验结果表明,所提算法在检测车辆目标时m AP提高了1.79%,也有效减少了在检测紧密车辆目标时出现的漏检现象。

金属离子对Trichoderma longibrachiatum UN32石斛碱型生物碱产量的影响

石斛碱是传统植物金钗石斛(Dendrobium nobile)的特征药用活性成分,结构上属于石斛型生物碱(dendrobine-type total alkaloids,DTTAs)。石斛碱的积累受周期和环境的影响,仅从植物中获取难以满足需求。该研究的对象Trichoderma longibrachiatum UN32是实验室前期通过复合诱变获得的产DTTAs的正突变株。为提高UN32的生物碱产量,使产物表达水平趋于稳定,该研究从UN32发酵培养基中无机盐的添加量出发,利用响应面法确定金属离子的最优配比。根据Plackett-Burman法设计筛选出对响应结果影响程度最显著的3个因素分别为Zn^(2+)、Cu^(2+)、Fe^(2+),其最佳添加时间和添加浓度分别是Cu^(2+)0.5 mmol/L(第6天)、Fe^(2+)0.4 mmol/L(第6天)和Zn^(2+)0.7 mmol/L(第3天)。响应面统计的结果显示,当模型响应值生物碱量达最大值时,Cu^(2+)、Zn^(2+)和Fe^(2+)的浓度分别为0.54、0.69、0.39 mmol/L,此时生物碱产量达到(317.36±6.48)μg,比初始培养基提高了72.68%。综上,金属离子及其不同组合对菌株UN32生物碱的积累具有促进作用,该方法具有较好的开发价值和应用前景。

Genetic Diversity of Jute Mallow (Corchorus spp.) Accessions Based on ISSR Markers

Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.

Strawberry (Fragaria spp.): Cultivation, Production, Consumption, and Marketing in Cameroon

Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

基于SPPs的二维多凹槽结构MIM波导透射特性的研究

不规则结构对波导的传播特性有着很大的影响,但对于MIM(Metal-Insulator-Metal,金属-介质-金属型)波导双边矩形槽并添加多凹槽结构对传播特性的影响方面的研究尚少。在研究内嵌凹槽位置对MIM波导透射特性影响的基础上,提出了在双矩形波导模型基础的内部添加多凹槽结构来影响波导的透射特性,并对波长与透射的关系及不同凹槽位置、不同凹槽数目的电场模图进行了对比分析。在凹槽位置改变时,Fano共振峰位置发生了移动,在小波长区域共振峰的数目也有所改变。随着上凹槽位置的增大,最大透射峰位置发生了蓝移,透射强度也有一定的增强;增加凹槽对数,得到波长与透射特性的关系曲线发生了改变,随着凹槽对数的增加,Fano共振峰的位置发生了一定的红移,且在小波长600~1 000 nm区域,Fano共振峰数目及透射峰值均发生了变化。这些研究结果可为预测金属缝隙波导制备过程中小尺度、多凹槽局部缺陷结构对其传播特性的影响提供理论依据。

智能手机BDS-3/GPS数据质量及SPP性能分析

使用可观测到BDS-3 B1I/B1C/B2a频率和GPS L1/L5频率的智能手机Xiaomi 11(青春版)作为研究对象,分别进行静态实验和不同场地的动态实验,分析手机输出的三频BDS和双频GPS原始观测数据质量及单频SPP性能。实验结果表明,智能手机的GNSS天线成本低致使其信号质量不佳,其中GPS L1频率和BDS B1C频率抗干扰性较强:BDS B1C频率定位结果在静态和动态实验中均较为稳定;GPS L1频率定位结果在动态实验中优于GPS L5频率,在静态实验中略差于GPS L5频率。

鸭SPP1基因的生物信息学分析、原核表达及其在鸭胚胎期骨骼肌中表达规律研究

分泌型焦磷酸蛋白1(SPP1)是一种具有多种功能的分泌型酸性糖蛋白,在肌肉发育过程中具有重要的调控作用,但SPP1基因在鸭骨骼肌中的结构和功能尚不明确。本研究选择胚胎期第17天(E17 d)、第21天(E21 d)、第24(E24 d)和第27天(E27 d)北京鸭和汉中麻鸭胸肌及腿肌组织作为实验材料,克隆了SPP1基因的CDS区序列并对该序列进行分析,进一步诱导基因表达,采用SDS-PAGE检测表达蛋白。同时采用qPCR方法分析SPP1基因在胚胎期北京鸭与汉中麻鸭胸肌和腿肌组织中的相对表达。结果表明:SPP1基因开放阅读框大小为915 bp,编码304个氨基酸,是有SP型信号肽的亲水性不稳定蛋白,无跨膜结构,有磷酸化和糖基化位点。qPCR结果表明,北京鸭骨骼肌SPP1的表达量在E27 d达到最高;而汉中麻鸭胸肌SPP1在E17 d的表达量最高,在E21 d的腿肌中表达量最高。在胚胎期北京鸭与汉中麻鸭骨骼肌的比较中,汉中麻鸭胸肌SPP1基因在E17 d时的表达量显著高于北京鸭,而在E27 d则低于北京鸭。北京鸭腿肌SPP1在E17 d和E27 d的表达量均高于汉中麻鸭,而在E21 d和E24 d则均低于汉中麻鸭。本研究揭示了鸭SPP1基因的结构及该基因在北京鸭和汉中麻鸭骨骼肌中的表达规律,为鸭生长发育的调控机制研究提供一定的参考。

Sequence analysis of rDNA intergenic spacer region (IGS) as a tool for phylogenetic studies in Trichoderma spp.

Different from ribosomal genes, which contain highly conserved sequences that are detected in all organisms, the intergenic spacer of rDNA (IGS) appears to be the most rapidly-evolving spacer region. For this reason we tested this region for phylogenetic studies. This report focuses on the study of IGS sequences of isolates belonging to Trichoderma section (T. viride, T. koningii, T. hamatum, T. erinaceus, T. asperellum) and Pachybasium section (T. harzianum, T. crassum, T. fasciculatum, T. oblongisporum, T. virens). Using the primer pair 28STD and CNS1, the Fast Start Taq DNA Polymerase (Roche), and a three temperature PCR protocol, products ranging from ca 1900 to 2400 bp were obtained from all tested isolates. The PCR product of 16 Trichoderma spp. isolates was cloned into a pGEM-TEeasy Vector (Promega) and sequenced. Based on a BLAST search we can conclude that the PCR product represents the whole IGS region. Multiple alignments of IGS sequences revealed two portions with different homology level. Portion A (ca 1660 bp) is the portion that contains 3’ end of 28S gene and is the more variable, while portion B (ca 830 bp), that contains the 3’ end of IGS region and the 5’ end of 18S gene, is the less variable. Comparing all sequences in region A 705 identical pairs occur out of 1704 total nucleotides (41.4%), while in region B identical pairs were 723 out of 832 total nucleotides (86.9%) . Sequence comparison of the two regions at intraspecific level (where it was possible) showed higher variability in region A (0.17%-6.8%) than in region B (0.0%-1.0%) . At interspecific level, performing all possible comparisons, the variability of region A (19.5%-52.7%) and B (0.8%- 16.9%). were significantly higher. Comparing sequences of species belonging to Trichoderma section variability of the two regions appears reduced if compared with that obtained from comparisons of species belonging to Pachybasium section. On the basis of sequence alignment, phylogenetic trees were obtained either with entire IGS, with region A, and with region B. Results of this analysis revealed that all isolates belonging to Trichoderma section grouped separately from isolates belonging to Pachybasium section. IGS region allowed us to group species according to their taxonomic position. The topology of the tree did not change substantially, varying in genetic distance only. Performing a GenBank search sequences representing the final portion of the IGS region of other fungal species were found, and we carried out a multiple alignment using also our sequences of Trichoderma spp. and Diaporthe helianthi. The phylogeny inferred from sequence alignment matched the generally accepted morphology-based classification and was identical to other molecular schemes at high taxonomic level. Data analysis was useful in establishing a broad-scale phylogeny of Ascomycota and was also useful in sorting them into statistically-supported clades. The tree showed that Trichoderma occurred in a well-supported terminal subclade of a larger clade that also contained other genera belonging to Hypocreales order. Sequence analysis of the Trichoderma spp. IGS region allowed us to design a specific PCR primer that was successfully used to amplify region A. The new reverse primer LCR2, that recognize all Trichoderma isolates, was identified in region B and confirmed for its specificity on the DNA of fungi belonging to other Ascomycota genera. Results obtained showed that IGS region seems to be an interesting and versatile tool for phylogenetic analysis, for resolving some taxonomic problems and for constructing specific primer useful for different purposes.