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。

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。

Inhibition of Chlamydospore Germination and Mycelial Growth of Trichoderma spp. by Chemical Fungicides

For exploring the influences of application and residue of chemical fungi- cides on chlamydospore preparations of Trichoderma spp., the effects of seven chemical fungicides on chlamydospore germination and mycelia growth of two bio- control fungi T. harzianum 610 and T. Iongibrachiatum 758 were studied. Carben- dazim, tebuconazole and difenoconazole showed strong toxicities, thiram and car- bexin showed moderate toxicities, and metalaxyl showed Mycelia growth of the two strains was more sensitive to most tested fungicides than those of chlamydospore germination. Chlamydospore germination of 610 was more sensitive to tested fungicides than those of 758, and mycelia growth of 758 was more sensitive to most tested fungi- cides than those of 610. Among the seven fungicides, 98% carbendazim had the strongest effects （ECru values were 1.64 and 0.05μpg/ml）, and 70% pentachloroni- trobenzene had the weakest effects （EC50 values were 1.64 and 0,05 μg/ml） for chlamydospore germination and mycelia growth of 610. As for 758, 98% carbendaz- im had the strongest inhibitory effects and 95% metalaxyl had the weakest inhibitory for chlamydospore germination of 756 （EC50 values were 0.62 and 1 108.61 μg/ml respectively）, whereas 96.2% tebuconazole showed the strongest inhibitory effects for mycelia growth of 758 （EC= value was 0.32μg/ml）, and 95% metalaxyl was the weakest （EC= value was 1 206.29 μg/ml）. According to the applied concentration of different fungicides in practice, we concluded that chlamydospore preparations of 610 and 758 could not be combined with carbendazim, tebuconazole, thiram and carboxin for controlling plant diseases, and the pesticide residues to the biocontrol effects should be kept in mind. Chlamydospore preparations of 610 and 758 can be and difenoconazole for controlling plant dis- eases, 758 chlamydospore preparations and germinated chlamydospore of 610 can be combined with metalaxyl for controlling plant diseases, and pesticide residue risk was not serious.

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。

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。

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

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.

Use of Trichoderma spp. on soil microbiology improvement for organic agriculture in Costa Rica

The soil is a complex system where processes have direct influence on crop nutrition and plant health. Unfortunately, most of the agricultural soil management practices, compact them producing poor oxygenation, low benefic microorganism populations and metabolic disorders in plants. Those factors induce abnormal plant development and predisposition to the attack of soil borne plant pathogens as: Sclerotium cepivorum, Sclerotium rolfsi, Sclerotinia sclerotiorum, Rhizoctonia solani, Rosellinia spp. But also, some air borne pathogens as Colletotrichum sp., are more aggressive under those conditions. In Costa Rica some practical trails done by farmers, have shown that the addition of Trichoderma spp. to organic fertilizers like vermicompost, Bocashi, and other composts, has a positive effect on the structure and microbial diversity, that improves nutrient movement in plants and pathogen suppression. Vegetative material of leather fern (Rumohra adiantiformis) infected by Rosellinia spp., planted with bocashi amended with. T. asperellum (T. harzianum), showed more tip root growth and new fern rhizomes. Also the plants produced higher number of fiddleheads and high quality fronds. Non-treated material showed a total loss. In some leaf vegetables as lettuce the use of vermicompost followed by Trichoderma viride application, inhibited S. sclerotiorum development on the crop, in this study sclerotia were infected and plant yields were increased. Compost previously inoculated with Trichoderma, inhibited 100% the Botrytis and R. solani infection, in nurseries, and plant nutrition was improved. The observed results are attributed to the antagonistic effect of Trichoderma on soil and airborne pathogens, production of growth regulators, solubilization of some microelements and better mineral absorption with the development of more roots and elimination of diseased roots. As conclusion, the organic substrates inoculated with Trichoderma spp., besides the organic matter source, they improve the structural characteristics of soil, promote the biochemical processes, increases the level of growth regulator substances and inhibit plant disease as well.

Proteomic mapping of secreted proteins of Trichoderma spp.

A series of highly taxonomically diverse Trichoderma strains were investigated using proteomic approaches, to investigate the utility of protein profiles as taxonomic markers and to identify proteins of potential economic importance. Initial studies have focused on a comparison of single strains of T. aureoviride, T. saturnisporum, T. polysporum, T. longbrachiatum and T. spirale, along with two strains of T. harzianum. All seven strains were grown in synthetic medium supplemented with 2%(w/v) glycerol, to maximize the diversity of extracellular protein production. Samples of secreted protein were separated by 2D gel electrophoresis and will be characterized by MALDI-TOF peptide fingerprinting.

Biocontrol Endotherapy with Trichoderma spp. and Bacillus amyloliquefaciens against Phytophthora spp.： A Comparative Study with Phosphite Treatment on Quercus robur and Fagus sylvatica

Phytophthora species are particularly aggressive plant pathogens and are often associated with the decline of many tree species, including oak and beech. Several fungi and bacteria species are known as potential antagonists usable as biological control agents. Phosphonate （H3PO3）, commonly branded as phosphite, has also been used in the past years to protect trees against invasive Phytophthora spp.. This study aimed at comparing the effects of selected antagonist microorganisms and phosphonate, when applied by microinjection or leaf treatment. Antagonistic species were first selected for their high inhibitory activity against problematic Phytophthora species, such as Phytophthora cactorum, P. quercina and P. plurivora attacking Quercus robur and Fagus sylvatica in Polish forests. Three endophytic species Trichoderma atroviride （two strains）, T. harzianum and Bacillus amyloliquefaciens showed a high control activity, and their efficacy was then assessed in comparison with a phosphonate treatment. Two application methods were experimented in this study： injection of a solution of spores or phosphonate into the sap vessels of beech or a foliar treatment on oak. Phosphonate and two strains of Trichoderma significantly reduced the necrotic area on oak leaves inoculated with P. plurivora and one strain of T. atroviride significantly reduced necrotic areas on beech branches. These results are therefore promising of a novel way to control Phytophthora spp. in forest stands and nurseries.

Performance of Red Onion （Bulb Type） in Fully Converted Organic Area as Affected by Frequency of Organic Fertilizer Application Combined with Trichoderma spp,

The study was conducted to determine the viability of producing organic onion under the fully converted area of Ramon Magsaysay Center for Agricultural Resources and Environment Studies （RMC-ARES）, Central Luzon State University, Philippines. Specifically, the study aimed to establish the fi＇equency of organic fertilizer and Trichoderma spp. application, employing split application, and determine the yield performance of red onion （bulb type）. The research was conducted for two consecutive dry seasons （2014 and 2015）. Red Creole variety was used with the following treatments： T1--organic fertilizer alone （8 ton/ha） at planting; T2--organic fertilizer （8 ton/ha） applied twice （at basal and 30 d after transplanting （DAT））; T3---organic fertilizer （8 ton/ha） applied twice （at basal and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied at planting; T4----organie fertilizer at 8 ton/ha rate ＋ Trichoderma spp. at the rate of 526 kg/ha, both applied twice （at planting and 30 DAT）; T5--organic fertilizer at 8 ton/ha rate applied twice （at planting and 30 DAT） ＋ Trichoderma spp. at the rate of 526 kg/ha applied thrice （at planting, 30 DAT and during bulb formation）. Results of the study showed that application of the recommended rate of organic fertilizer twice （at planting and 30 DAT） ＋ three times application of Trichoderma spp. （at planting, 30 DAT and during bulb formation） consistently produced bigger bulb during the first and second trial of the study, compared to other treatments evaluated. Consequently, higher marketable yield was produced with 15.33 ton/ha during the first trial and 14.50 ton/ha on the second trial.

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).

香菇与木霉互作方式及绿霉病防治研究进展

木霉属(Trichoderma spp.)病原菌诱发的绿霉病,是香菇(Lentinula edodes)栽培过程中常见的病害之一。木霉属病原菌不仅可污染培养料,与香菇菌丝竞争营养和生存空间,而且可感染香菇菌丝体,引起香菇菌棒腐烂,造成严重的经济损失。笔者综述引起香菇绿霉病的木霉种类,香菇和木霉的互作方式,绿霉病的防治方法,香菇抗木霉能力,以及木霉感染真菌病毒的相关研究,期望为香菇绿霉病的防治提供参考。

粘帚霉(Gliocladium spp.)不同菌株对几种病原菌的抑菌作用测定

报道了粘帚霉35个菌株对尖孢镰刀菌(Fusariumoxysporf.sp.Vasinfectum)、立枯丝核菌(Rhiizoctoniaso lani)、核盘菌(Sclerotiniasclerotiorum)、灰葡萄孢菌(Botrytiscinerea)、辣椒疫霉菌(Phytopthoracapsici)及细交链孢菌(AlternariatenuisNees)的拮抗作用和重寄生作用。结果表明:HL-1-1、SH-1-1、SYP-1-1、SYP-4-2、GW-2-1、STG-4-1等6个菌株对供试的6种重要的植物病原真菌均表现出较强的抗菌作用,可作为具有生防潜力的优良菌株进一步研究和利用。粘帚霉菌株菌丝与立枯丝核菌菌丝并行生长,并从菌丝上长出许多分支,缠绕在立枯丝核菌菌丝上形成许多缠绕圈,或菌丝穿过立枯丝核菌菌丝生长。

长枝木霉Trichoderma longibrachiatum T6水分散粒剂的研制

以土壤中分离得到的一株拮抗菌——长枝木霉Trichoderma longibrachiatum T6为研究对象,通过优化培养基配方及助剂类型的筛选,成功研制了长枝木霉T.longibrachiatum T6水分散粒剂,并测定了其贮存稳定性。结果表明：制备长枝木霉T6水分散粒剂的最佳配方（质量分数）为：羧甲基纤维素（紫外保护剂）0.5%,碳酸钙（稳定剂）4%,聚乙烯基吡咯烷酮（PVP,黏结剂）5%,可溶性淀粉（崩解剂）5%,凹凸棒土（载体）5%及十二烷基硫酸钠（润湿剂）5%。由此配方制备的水分散粒剂中孢子含量为5.6×10^8 cfu/g,悬浮率53%,p H值6.0,水分含量3.5%,湿润时间52 s,且在冷藏温度为（4±2）℃条件下的稳定性显著高于在室温（25℃）下的。各项检测结果均符合国家标准。

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%)。

盐胁迫下耐盐性木霉菌的筛选与鉴定

对分离于甘肃省民勤县的6株木霉菌进行耐盐性筛选和鉴定。结果表明,随着NaCl浓度(0 to 150 mmol/L)增加显著降低6株木霉菌(TG1 to TG6)的菌落直径。与其他5株木霉菌相比,不同浓度NaCl胁迫下菌株TG1具有较强耐盐性。当NaCl浓度为50 mmol/L时,培养2 d后菌株TG1产孢量和菌落直径与对照相比无显著差异,但是其孢子萌发率增加10.59%。菌株TG1在PDA培养基上菌落正面呈暗绿色,菌落背面呈暗黄色,分生孢子球形至椭圆形。分生孢子梗直角分枝,结合其形态特征将菌株TG1鉴定为T.longibrachiatum。构建菌株TG1的TEF和ITS系统发育树,结果表明菌株TG1的TEF和ITS序列分别与T.longibrachiatum IMI 297702(EU401578.1)和T.longibrachiatum(MT889709.1)序列相似性为99.22%和100.00%。因此,结合形态特征和分子生物学分析将菌株TG1鉴定为T.longibrachiatum TG1。与对照相比,菌株TG1在50、100和150 mmol/L NaCl胁迫下产生IAA浓度分别为1.25、1.35和1.56μg/mL,而对照为0.92μg/mL。同时,在50、100和150 mmol/L NaCl胁迫下,TG1菌株ACC脱氨酶活性分别为0.1、0.16和0.17μmolα-ketobutyrate mg/h,而对照为0.09μmolα-ketobutyrate mg/h。

Study on the Liquid Fermentation Condition of Trichoderma hamatum Th12 Strain

[Objective] The research aimed to study the optimum liquid fermentation condition of Trichoderma hamatum Th12 strain,which provided the theory basis for studying and developing the biological control agent of Trichoderma spp.[Method] By using the diluted soil plate method and the plate confrontation method,Trichoderma hamatum Th12 strain was identified.Moreover,the influences of carbon source,nitrogen source,fermentation time,fermentation temperature,initial pH,inoculation amount,bottling capacity and shaker speed on the mycelium yield of Trichoderma hamatum Th12 were studied.[Result] The optimum liquid fermentation conditions of Trichoderma hamatum Th12 strain were：glucose as the carbon source,peptone as the nitrogen source,fermentation temperature was 25 ℃,initial pH was 6,inoculation amount was 0.8 ml,bottling capacity was 50 ml,shaker speed was 180 r/min.Trichoderma hamatum Th12 strain was cultivated 3 d under the condition,and the mycelium yield was the highest.[Conclusion] Under the optimum liquid cultivation condition,Trichoderma hamatum Th12 strain could provide the mycelium amount which was used for preventing and controlling Fusarium oxysporum and Rhizoctonia solani of lawn to the utmost extent.

Biological Control of Soilborne Pathogens （Fusarium oxysporum F, Sp. Cucumerinum） of Cucumber （Cucumis sativus） by Trichoderma sp,

In this study, the efficacy of the native isolates of Trichoderma species to promote the growth and yield parameters of cucumber and to manage Fusarium wilt disease under greenhouse conditions were investigated. Ninety native Trichoderma antagonists were isolated from Grassland and forest soil in different geographical regions of Inner Mongolia, China. Applications of T. cf. harzianum T1, T2, T3, T4, T5, T6, T7, TS, T10, T11 and T. atroviride （T9） exhibited the least disease incidence （by 0%） also the same strains shows 100% of relative control effect. Cucumber seedling treated with T. cf. harzianum （T2 and T1） isolates showed a significant stimulatory effect on plant height （by 13 and 14 cm respectively） and the highest shoot and root fresh weight were recorded by T. asperelloides （T27） and T. gamsii （T17） by 1.62 gm and 0.97 gm respectively, in comparison to untreated control and treated control （10 cm and 4 cm, 1.27 gm and 0.22 gm and 0.82 gm and 0.10 gm）. Therefore, the antagonist （T1, T2, T3, T4, T5, T6, T7, T8, T8, T10, and T1 1） is chosen to be the most promising bio-control agent for Fusarium oxysporum f. sp. Cucumerinum and further study have to be exploited for sustainable disease management program.

Induced Systemic Resistance in Two Genotypes of <i>Brassica napus</i>(AACC) and <i>Raphanus oleracea</i>(RRCC) by <i>Trichoderma</i>Isolates against <i>Sclerotinia sclerotiorum</i>

Two different species, Trichoderma viride TV10 and Trichoderma harzianum TH12 from 30 Trichoderma isolates were selected out based on their high growth inhibition of the phytopathogen Sclerotinia sclerotiorum (Lib) de Bary, which reached 84.44% and 100%, respectively. Their untreated culture filtrates (CF) and culture filtrates treated with heat (CFH) also were tested for growth inhibition of the pathogen in potato dextrose agar (PDA). Morphological and molecular characterisation by internal transcribed spacer (ITS) PCR provided consistent identification of these isolates. The degree of infection and disease index (DI) of S. sclerotiorum were examined in Brassica napus (AACC) and Raphanus alboglabra (RR) and Brassica alboglabra (CC). The results revealed that Raphanus alboglabra showed higher disease resistance than that of B. napus. Biotic elecitors T. harzianum TH12 and T. viride TV10 and their CF and CFH demonstrated the ability to cause induced systemic resistance (ISR) in B. napus and Raphanus alboglabra against sclerotinia stem rot (SSR) disease. Furthermore, a high ability to reduce the degree of infection and DI in B. napus with the biotic elicitors T. harzianum TH12 and T. viride TV10 was observed, with numbers reaching 7.22% to 6.67% and 17.78% to 11.67%, respectively. When CF were used, reached 20.00% to 16.67% and 33.33% to 23.33%, respectively;with CFH, values reached 35.00% to 21.67% and 37.78% to 28.33%, respectively. While in Raphanus alboglabra the degree of infection and DI reached 0.00% and 0.00% with all biotic elicitors treatments. These results show that biotic elicitor treatments significantly (P B. napus and Raphanus alboglabra ranked as most effective. This study showed for the first time the ability of genotype Raphanus alboglabra (RRCC) to demonstrate resistance against S. sclerotiorum with or without treatment by biotic elicitors and the ability of genotype B. napus (AACC) to demonstrate resistance to the pathogen after treatment with biotic elicitors.