Phoma black stem severity and phytoestrogen production in annual Medicago spp. is primarily determined by interaction of cultivar and pathogen isolate     

Mahtab Omidvari  Gavin R. Flematti  Ming Pei You  Payman Abbaszadeh-Dahaji  Martin J. Barbetti 《Plant pathology》2022,71(4):860-872

Phoma black stem and leaf spot disease (caused by Phoma medicaginis) not only diminishes forage and seed yield but stimulates production of detrimental phytoestrogens in annual Medicago spp. This study aimed to evaluate relationships between disease development from five isolates of P. medicaginis on 16 cultivars with production of coumestrol and 4′-O-methylcoumestrol. In the presence of P. medicaginis, Sava had the highest coumestrol and 4′-O-methylcoumestrol (640 and 85 mg/kg, respectively) followed by Caliph (253 and 15 mg/kg, respectively). In the absence of P. medicaginis, Jemalong and Paragosa showed highest and lowest coumestrol (137 and 0 mg/kg, respectively). 4′-O-methylcoumestrol was not produced in disease-free plants, but coumestrol was. Disease incidence and severity on leaves and on petiole/stems, and consequent leaf yellowing severity ranged from 5%–98.7%, 0%–100%, 4.4%–98.7%, 1.7%–100%, and 0%–85%. Sava, Paraponto, Harbinger, and Serena were most susceptible, while Tornafield and Caliph were least susceptible. There was significant overall positive correlation of disease incidence/severity factors across cultivars (p < 0.01) with both coumestrol and 4′-O-methylcoumestrol. Jemalong was least responsive and Paragosa and Sava most responsive to coumestrol production following P. medicaginis inoculation. Coumestrol in inoculated Paragosa increased to 373 mg/kg in comparison with 0 mg/kg in controls. These findings are of critical importance towards developing less disease-susceptible annual Medicago spp. producing less detrimental phytoestrogens. Least susceptible cultivars like Tornafield and Caliph can be used to manage yield loss, whilst least responsive cultivars to phytoestrogen production like Caliph also can help to reduce phytoestrogen production.  相似文献   

A glasshouse progeny test for resistance to gangrene (Phoma foveata)     

R. L. Wastie  G. R. Mackay  P. D. S. Caligari  Helen E. Stewart 《Potato Research》1990,33(1):131-133

Summary Tubers were obtained from 80 glasshouse-grown seedlings of each of twelve progenies, inoculated withPhoma foveata Foister, and the mean percentage of infected tubers recorded. There was a good correlation (r=0.798) between this assessment and that made previously on field-grown tubers of eleven of the progenies. A gangrene test on glasshouse-grown tubers is suggested as a more rapid means of identifying progenies with useful levels of resistance.  相似文献   

Mechanism of induced systemic resistance against anthracnose disease in cucumber by plant growth-promoting fungi     

Mohsen Mohamed Elsharkawy  Manchanahally Byrappa Shivanna  Manchanahally Shivanna Meera 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):287-299

Plant growth-promoting fungi (PGPF) such as Phoma sp. (isolates GS8-1, GS8-2 and GS8-3) and non-sporulating fungus (isolate GU21-2) were tested for their ability to induce systemic resistance against Colletotrichum orbiculare in cucumber. These isolates, used as colonized barley kernels to natural soils, induced systemic resistance in the greenhouse as well as in the field. Different elicitors from PGPF such as cell walls retaining or lacking protein and lipids, cell walls lipid fraction, and three fractions of culture filtrate (CF) with different molecular weight ranges were tested for their ability to elicit the defense response of cucumber plants under controlled conditions. Cell wall fraction lacking protein and lipids and the cell wall lipid fraction from root colonizing isolates GS8-1, GS8-2, and GS8-3 protected plants against C. orbiculare. While, only cell wall lipid fraction and CF fractions of different molecular weight ranges of the isolate GU21-2 protected plants against C. orbiculare infection. Methanol-soluble substances from CF fractions with molecular weight greater than 12,000 and less than 8000 consistently protected plants against the pathogen. Germination of C. orbiculare spores decreased significantly at 72 h of incubation on leaves of PGPF-protected plants. Isolate GU21-2 was the most effective in inhibiting spore germination. On the other hand, isolates GS8-1 and GU21-2 induced lignifications in the hypocotyls of seven-day-old cucumber seedlings after challenge inoculation with C. orbiculare. Three-week-old cucumber plants treated with isolate GU21-2 and challenged with C. orbiculare showed increased activities of exo- and endo-forms of glucanase and chitinase, as well as peroxidase and polyphenol oxidase in the second true leaves. Induction treatment with isolate GS8-1 also increased the activities of these enzymes with the exception of exo-glucanase. This study shows that the inoculation of PGPF or its CF resulted in additive effect on the suppression of anthracnose disease in cucumber.  相似文献   

Systemic growth of Leptosphaeria maculans from cotyledons to hypocotyls in oilseed rape: influence of number of infection sites, competitive growth and host polygenic resistance     

R. Travadon  B. Marquer  A. Ribulé  I. Sache  J. P. Masson  H. Brun  R. Delourme  L. Bousset 《Plant pathology》2009,58(3):461-469

The influence of competitive effects between two isolates, of the number of infection sites on cotyledons and of host polygenic resistance on the systemic growth of Leptosphaeria maculans , the cause of phoma stem canker in oilseed rape ( Brassica napus ), were investigated. Controlled-condition experiments were conducted with two oilseed rape doubled haploid lines, one susceptible and the other with a high level of polygenic resistance, inoculated via wounded cotyledons with conidial suspensions obtained from two isolates. Expression of cankers in plants was enhanced by exposing inoculated plants to low temperature (6°C) followed by warm temperature (20°C). The fungus was detected by PCR amplifications of three minisatellite markers in all stems with visible canker symptoms and also in the stems of 14 of the 59 plants without visible cankers on the hypocotyls. Disease severity increased with the number of infection sites on cotyledons: in one of the three replicate experiments, the mean external necrosis length on the hypocotyl ranged from 6·47 to 35·3 mm for one and eight infections sites on cotyledons, respectively. The probability of an isolate reaching the hypocotyl from inoculated cotyledons decreased with increasing competing inoculum load on cotyledons: for instance, for isolate A290v it decreased from 1 when inoculated alone to 0·28 when coinoculated with six drops of competing isolate P27d. Polygenic resistance significantly reduced disease incidence and severity. For instance, in one of the three replicate experiments, disease incidence ranged from more than 74% in susceptible plants to 16% in resistant ones, while mean external necrosis length was up to 35·3 and 6·5 mm on susceptible and on resistant plants, respectively. This study offers new possibilities for assessing levels of polygenic resistance to stem canker in B. napus and studying the aggressiveness of L. maculans isolates.  相似文献   

一株抗马铃薯坏疽病生防细菌B-401产抑菌物质条件优化及稳定性          下载免费PDF全文

畅涛  冯中红  杨成德  薛莉 《中国生物防治学报》2016,32(3):365-371

以马铃薯坏疽病菌为靶标菌株,采用含药平板法对高寒草地禾草内生细菌B-401产抑菌物质条件及抑菌物质的稳定性进行了研究。结果表明,生防菌株B-401产抑菌物质的最佳培养基配方为牛肉膏8g、酵母浸膏5.0g、葡萄糖10g、水1000mL,最适温度为23.4℃,最适pH值为7,最佳装液量为35.2mL/150mL三角瓶,最佳培养方式为光照条件下振荡培养24h,最适发酵时间为96h,优化验证试验结果表明,其对马铃薯坏疽病菌的EC₅₀＝0.111μL/mL,是优化前EC₅₀＝3.196μL/mL的3.47%。菌株B-401所产抑菌物质在25~90℃具有较好稳定性,抑菌活性均大于75%,在100℃及以上高温处理后抑菌物质活性降低;对酸碱性和紫外照射稳定,相对活性分别在77.45%和98%以上;对金属离子Na⁺、Mg²⁺和Mn²⁺稳定,相对活性达99%以上,而对Ag⁺、Cu²⁺、Zn²⁺和Fe³⁺较不稳定。  相似文献   

马铃薯坏疽病Phoma foveata生防菌的筛选及鉴定   总被引：1，自引：0，他引：1  

畅涛  王涵琦  杨成德  薛莉  陈秀蓉  任月芹  王玉琴 《中国生物防治》2014,(2):247-252

采用平板对峙法筛选到了马铃薯坏疽病的生防菌 ZA1,其对马铃薯坏疽病菌的抑制率为71.83%;通过形态特征和生理生化测定,结合16S rDNA和gyrB基因序列同源性分析,鉴定该菌为莫海威芽孢杆菌Bacillus mojavensis。抑菌谱测定表明,菌株ZA1对番茄早疫病菌Aalternaria solani、马铃薯褐腐病菌Stysanus stemonitis、马铃薯干腐病菌Fusarium oxysporum和马铃薯炭疽病菌Colletotrichum coccodes的抑制率分别达64.30%、41.05%、61.42%和74.92%。在贮藏库中进行10倍液喷雾,对马铃薯坏疽病的防效达64.31%。  相似文献   

白藓茎点霉叶斑病菌的生物学特性及药剂敏感性     

李海洋  魏春艳  刘丽玲  李海滨  白庆荣 《吉林农业大学学报》2017,39(3)

对我国新见白藓茎点霉叶斑病的症状进行了描述,结合病原形态特征、培养特性及rDNA-ITS序列分析结果,确定该病害由Phoma dictamnicola引起。病菌的生物学特性研究结果表明:病菌菌丝在10~30℃可生长,25℃为最适生长温度;在pH 4~11可生长,pH为7时最适合菌丝生长;在马铃薯葡萄糖琼脂培养基上菌丝生长最快,在水琼脂培养基上菌丝生长最慢;在以葡萄糖为主要碳源和蛋白胨为主要氮源的培养基上生长最好。病菌对50%咪鲜胺乳油、10%苯醚甲环唑水分散粒剂、40%氟硅唑乳油、50%醚菌酯水分散粒剂敏感性较高,其EC500.1μg/m L;其次为250 g/L吡唑醚菌酯乳油和25%丙环唑乳油,0.1μg/m LEC501.0μg/m L。  相似文献   

11株草茎点霉培养特征、致病力及RAPD分析   总被引：3，自引：0，他引：3  

谷祖敏  纪明山  魏松红  祁之秋  王英姿 《吉林农业大学学报》2010,32(2):140-144

从辽宁的沈阳、抚顺、鞍山等地采集的鸭跖草叶斑病病叶上共分离得到11个菌株。这些菌株在培养形态、生长速率、产孢能力、致病能力和产毒能力方面差异显著。其中SY1菌株的生长速率最快,SY4菌株的产孢能力最强。SYAU-06菌株的致病力最强,接种在鸭跖草叶片上发病率达到97.33%,病情指数为87.23,显著高于其他菌株。在液体培养基中SYAU-06菌株的产毒量最多,毒素的致病性也最强,在鸭跖草叶片上可形成面积为13.63 mm2的病斑。11个菌株基因组DNA经RAPD分析表明,不同菌株间扩增图谱差别明显,表现出各菌株间明显的遗传多态性。经聚类分析显示草茎点霉不同菌株的RAPD类群与致病力有一定的相关性。  相似文献   

陕西省苜蓿茎点霉叶斑病病原菌的鉴定   总被引：1，自引：0，他引：1  

李洪建  李芳红  史健  呼天明  程积民  钱永华  焦锋 《草地学报》2015,23(6):1310-1316

近期发现了陕西省紫花苜蓿(Medicago sativa)一种苜蓿茎点霉叶斑病,为了准确鉴定该病害,开展了一系列病原鉴定试验。病叶片典型症状为叶尖上的深褐色斑点融合扩大呈“轮纹状”病斑;病原物的分生孢子无色透明,圆柱形,无隔单胞,大小为7×1.25 μm;以病原菌rDNA-ITS(核糖体DNA 内转录间隔区)序列的系统发育树的分析表明,病原菌与Phoma medicaginis var. Medicaginis(DQ109960)亲缘关系最近,NJ法中的相似性达到99%,UPGMA法中的相似性为98%;离体叶片接种验证病原菌具有致病性,结果表明:苜蓿茎点霉叶斑病的病原菌为苜蓿茎点霉(Phoma medicaginis var. Medicaginis)。  相似文献   

草茎点霉毒素Ⅲ衍生物的合成与除草活性     

刘欣  李兴海  高云云  王智  纪明山 《农业科学与技术》2016,(1):100-105

[目的]提高草茎点霉毒素Ⅲ(2-甲基-3,5-二硝基苯甲酸甲酯)的除草活性,对其结构进行衍生优化.[方法]以邻甲基苯甲酸为起始原料,经硝化、酰化等反应合成了16个新的苯甲酸酯类化合物,其结构均通过IR和1HNMR确证,并对合成的化合物进行除草活性筛选.[结果]在100μg/ml时,J-L-59对稗草Echinochloa crusgalli根的抑制率为93.7％;活体盆栽试验结果表明,在有效成分1000 g/hm2时,J-L-59对苘麻Abutilon theophrasti和反枝苋Amaranthus retroflexus的鲜重防效均达100％.毒力测定结果表示,J-L-59对反枝苋Amaranthus retroflexus的ED50值为有效成分94.06 g/hm2.[结论]J-L-59有较高的除草活性.  相似文献