魔芋白绢病病原齐整小核菌(Sclerotium rolfsii)的生物学特性与室内毒力

【目的】探明魔芋白绢病的病原微生物类型及其生物学特性,筛选高效杀菌剂,为魔芋白绢病田间综合防治措施的制订和实施提供理论依据。【方法】采用组织分离和土壤稀释法,对具有典型白绢病症状的魔芋植株和附近土壤进行病原分离和纯化,通过形态学和分子系统学鉴定病原菌;采用菌丝生长速率法探究病原的生物学特性和7种药剂(苯醚甲环唑、吡唑醚菌酯、氟硅唑、戊唑醇、噻呋酰胺、烯唑醇及丙环唑)对其室内毒力。【结果】魔芋白绢病病原为齐整小核菌(Sclerotium rolfsii),其菌丝在OA和PDA培养基生长速度最快,培养3 d,菌落直径达7 cm,菌丝生长速率为2.33 cm/d;25~30℃为最适培养温度,培养3 d,菌落直径达7.2 cm,菌丝生长速率为2.48 cm/d;pH为5~7的偏弱酸环境有利于菌丝生长,生长速率最高达2.33 cm/d;氮源以蛋白胨、碳源以可溶性淀粉利于病原菌丝生长,生长速率分别为2.14 cm/d和2.43 cm/d,显著高于其他处理。戊唑醇、烯唑醇、噻呋酰胺、苯醚甲环唑、吡唑醚菌酯和丙环唑对白绢病均具有很好的抑制作用,其中,戊唑醇的防效最好,EC_(50)为0.101 mg/L;其后依次为烯唑醇、噻呋酰胺、苯醚甲环唑、吡唑醚菌酯和丙环唑,EC_(50)依次为0.165 mg/L、0.185 mg/L、1.026 mg/L、1.842 mg/L和2.112 mg/L。【结论】S.rolfsii为引起土传病害魔芋白绢病的病原,其适宜生长温度为25~30℃,弱酸和营养丰富的环境有利于病原菌丝生长,戊唑醇可有效抑制菌丝生长。

加拿大一枝黄花白绢病(Sclerotium rolfsii)菌株SC64的生物学特性研究

在实验室条件下初步研究了加拿大一枝黄花白绢病菌株SC64的形态特征、致病性和生物学特性。结果表明:引起加拿大一枝黄花白绢病的病原物是罗氏白绢小菌核菌(Sclerotium rolfsii Sacc.);病菌最适生长培养基为Richard固体培养基和PDA,菌丝生长温度为15～40℃,最适30℃;在偏酸性条件下生长较好,生长适宜pH值为4.0～6.0,最适为5.0;在所测试的碳源中,对蔗糖的利用最好,对乳糖和半乳糖利用最差;氮源测试结果显示对蛋白胨和硝酸钾利用最好,对尿素的利用最差。菌核萌发温度为15～40℃,最适为30℃;菌核在含水量≥50%的麸皮基质上萌发较好;适宜萌发的pH值范围为3.0～9.0。菌丝的致死温度为45℃10 min,菌核的抑制萌发温度为50℃10 min。

室内模拟旱直播稻田环境下齐整小核菌Sclerotium rolfsii菌株SC64致病力的影响因子及除草效果的研究

本文通过温室盆栽试验,以鳢肠Eclipta prostrata为例,研究杂草叶龄、不同含菌丝体基质接种量以及温度、土壤湿度、保湿期时间等环境因子对菌株SC64侵染鳢肠的影响。在此基础上,温室条件下模拟旱直播水稻田环境下菌株SC64防治节节菜Rotala indica、异型莎草Cyperus difformis、鸭舌草Monochoria vaginalis和耳叶水苋Ammannia arenaria的试验。结果表明,鳢肠幼苗在5叶期以下,接种含菌丝体固体基质剂量在100g m 2以上,温度范围27～33℃,土壤相对饱水90%左右,并且接菌后湿度保持至少24 h,是菌株SC64达到理想除草效果的必需条件。温室模拟试验结果显示,接种含菌丝体固体基质剂量在120 g m 2时,28 d可引起节节菜和鸭舌草81%和74%的植株死亡率及83.8%和82.5%的鲜重抑制率;对异型莎草和耳叶水苋的防效稍差,仅能引起约50%的植株死亡率及60%～65%的鲜重抑制率。这表明菌株SC64可有效控制阔叶杂草,具有开发作为生物除草剂的潜力。

Streptomyces sp. RP1A-12 mediated control of peanut stem rot caused by Sclerotium rolfsii

Sclerotium rolfsii Sacc. is a destructive soilborne fungal pathogen with a wide host range that includes peanuts. Biological control offers an interesting alternative to fungicides for sustainable management of soilborne diseases. The current investigation is aimed at evaluating one potential biocontrol agent Streptomyces sp. RP1 A-12 for growth promotion and the management of peanut stem rot disease caused by S. rolfsii under field conditions. Preliminary studies conducted under in vitro and the greenhouse conditions showed promising results against the stem rot pathogen. Further in vitro and pot experiments conducted to assess Streptomyces sp. RP1 A-12 for its growth promoting abilities using whole organisms have shown an increase in seed germination, root and shoot length. Other parameters like nodule number and plant biomass were also significantly increased over control treatments indicating that the test bioagent possesses growth promoting abilities along with disease suppression capabilities. Subsequently field studies were carried out for two consecutive rainy seasons. The bioagent was applied as whole organism and partially purified crude metabolites. Results indicate the bioagent reduced stem rot disease incidence by 64–67% and 22–49% respectively in two field trials conducted with notable increase in yield. Partially purified Streptomyces sp. RP1 A-12 metabolites exhibited an even greater effect in reducing the incidence and severity of stem rot compared to the pathogen inoculated control.

The quantity of OA and activity of cellulase and polygalacturonase are involved in variation of virulence in Sclerotium rolfsii

In order to understand the pathogenic mechanisms of Sclerotium rolfsii on peanut and to analyze the variation of virulence in S.rolfsii strains,the highly virulent strain(ZY2)and weakly virulent strain(GP3-1)were investigated under both in vivo and in vitro conditions.The results indicated that S.rolfsii directly infected peanut by producing infection cushions.ZY2 formed infection cushions earlier than GP3-1,and ZY2 produced a greater number of infection cushions compare to GP3-1.Both strains could utilize cellulose,xylose,or polygalacturonic acid in the Czapek medium.The activities of cellulase(CL)and polygalacturonase(PG)in the inoculated peanut stems increased significantly at 9 h after inoculation.The activities of CL and PG produced by ZY2 in the inoculated stems were significantly higher than that produced by GP3-1.Both strains could produce oxalic acid(OA),and the content of OA produced by ZY2 in the inoculated stems was higher than that produced by GP3-1.In summary,it suggested that S.rolfsii destroyed peanut cells through physical and biochemical factors by secreting a large amount of OA,CL and PG during the formation of infection cushions.The difference in OA content,activity of CL and PG produced by highly and weakly virulent strains played important roles in variation of virulence.

Evaluation of Selected Chemical,Biological Fungicides,and Induced Resistance to Control White Rot(Sclerotium rolfsii Sacc.)on Tomato

Tomato(Solanum lycopersicum)is one of the most widely grown and consumed as fresh vegetable in the world.Sclerotium rolfsii Sacc.is one of the most destructive diseases and affects more than 500 plant species.This study was conducted for“Evaluation of Selected Chemical,Biological Fungicides,and Induced Resistant to Control White Rot(Sclerotium rolfsii Sacc.)on Tomato”.The experiment was conducted at the Royal University of Agriculture and divided into two sections.The first section conducted under in vitro condition consists of four treatments T1 control treatment,T2 copper hydroxide,T3 azoxystrobin+difenoconazole,T4 metalaxyl+mancozeb in Nagoya Laboratory,and had been starting from 11st May to 15th May 2020.Section two was conducted in a pot in net-house which started from 1st January 2019 to 19th February 2019 and 1st January to 19th February 2020 and arranged in RCBD(Randomized Completely Block Design)with six replications and nine treatments.T0 negative control,T1 inoculate but not treatment,T2 metalaxyl+mancozeb,T3 azoxystrobin+difenoconazole,T4 copper hydroxide,T5 acibenzolar-S-methyl,T6 chicken dung+Trichoderma harzianum,T7 acibenzolar-S-methyl+chicken dung+Trichoderma harzianum,T8 acibenzolar-S-methyl+metalaxyl+mancozeb.Data were collected on colonizing diameter in vitro.For pot experiment collected on disease incidence,incubation period Based on the result under in vitro condition metalaxyl+mancozeb highly inhibited germination of Sclerotium rolfsii when compared with another treatment.However,the application of copper hydroxide seems less effective compared with control.For in pot experiment,when treated after symptom of southern blight appeared to seem less effective on the severity of southern blight.In contrast,when applied as a protectant and curative when symptoms appeared only systemic fungicide azoxystrobin+difenoconazole significantly reduced the severity of Sclerotium rolfsii and delayed incubation period while compared with other treatments(p<0.05)and was followed by metalaxyl+mancozeb,whereas,copper hydroxide,acibenzolar-S-methyl,chicken dung+Trichoderma harzianum,acibenzolar-S-methyl+chicken dung+Trichoderma harzianum,acibenzolar-S-methyl+metalaxyl+mancozeb were less effective(p>0.05).Based on the three experiments we can assume that fungicide is more effective in reducing the growth of the pathogen and delaying the incubation period of fungal colonization when compared with biological control and induced resistance.

上海城市绿地土壤立枯丝核菌(Rhizoctonia solani)和齐整小核菌(Sclerotium rolfsii)空间分布特征

为了明确严重危害上海园林绿化植物的立枯丝核菌(Rhizoctonia solani)和齐整小核菌(Sclerotium rolfsii)在绿地土壤中的分布特征,本研究采用实时荧光定量PCR方法对土壤中两种病原菌ITS基因丰度进行了定量测定,结合土壤理化性质,分析了两种病原菌在上海绿地土壤中的分布及主要影响因素。结果表明:绿地土壤pH偏碱性,含水率偏高,各理化指标变异系数较高;绿地土壤中立枯丝核菌和齐整小核菌的检出率分别为99.7%和11.6%,检出样品ITS基因的平均丰度分别为9.09×10^(5)和2.42×10^(5)copies·g^(-1);立枯丝核菌ITS基因丰度在公园绿地和道路绿地土壤中存在显著性差异(P<0.05),在中心城区和郊区绿地土壤中的丰度差异不显著(P>0.05),表明其丰度受绿地类型影响显著;齐整小核菌ITS基因丰度在公园绿地和道路绿地以及中心城区和郊区绿地土壤中差异均不显著(P>0.05),其丰度与土壤全铬、全镍呈显著负相关,与土壤全砷呈极显著负相关。研究结果为防控上海绿地土壤中立枯丝核菌和齐整小核菌病害的发生提供了基础数据。

防控花生白绢病的根际放线菌分离鉴定及防效评价

花生白绢病是由齐整小核菌Sclerotium rolfsii Sacc.引起的发生在花生茎基部的真菌病害,严重制约花生的品质与产量。本研究利用稀释涂布法从怀牛膝根际土壤中分离纯化了116株放线菌,并从中筛选鉴定了能够防控花生白绢病的菌株。通过平板对峙试验筛选得到两株抑菌活性较好且稳定的菌株Soil-1-5和Soil-3-28,它们对齐整小核菌的抑制率分别为80.43%和92.34%。根据形态学观察、生理生化试验及16S rRNA基因序列分析鉴定,两株菌分别被鉴定为疮痂链霉菌Streptomyces scabiei和藤黄灰链霉菌Streptomyces luteogriseus。采用菌丝生长速率法测定了拮抗菌株无菌发酵滤液对植物病原菌的抑制作用。结果表明,菌株Soil-1-5和Soil-3-28的无菌发酵滤液稀释5倍后对齐整小核菌的抑制率分别为73.67%和57.11%,且对禾谷镰孢菌等6种植物病原菌均有不同程度的抑制作用。此外,两菌株的无菌发酵滤液对齐整小核菌菌核萌发和菌核形成也有较好拮抗作用。盆栽试验结果表明,菌株Soil-1-5和Soil-3-28对花生白绢病的防治效果分别为51.92%和31.74%,其中菌株Soil-3-28对花生生长有促进作用。综上,菌株Soil-1-5和Soil-3-28对花生白绢病有较好的防治效果,具有潜在应用价值。

花生白绢病菌拮抗细菌的分离鉴定及其温室抑菌促生效果

由齐整小核菌Sclerotium rolfsii Sacc.侵染引起的土传真菌性病害——花生白绢病,严重威胁花生的生产。为挖掘对花生白绢病有较好防治效果的拮抗细菌,利用稀释涂布法从感染S.rolfsii的植株根际土壤中分离得到570株细菌,采用平板对峙法筛选出32株S.rolfsii拮抗细菌,结合16S rRNA基因序列、形态学及生理生化特征,确定细菌的分类学地位。通过S.rolfsii与拮抗细菌的发酵液共培养和盆栽试验结果表明:在所筛选的32株拮抗细菌中,4株细菌HNZZ23、HNKF5、HNXX14和HNXX169对S.rolfsii的抑制时间长,抑制效果好,其发酵液对S.rolfsii菌丝生长的抑制率分别为85.30%、85.88%、85.16%和91.00%,对S.rolfsii菌核萌发的最大抑制率分别为100%、85.33%、82.67%和93.33%。菌株HNZZ23和HNXX14的发酵液对盆栽花生白绢病的防治效果分别为30.50%和25.73%,且菌株HNZZ23对花生植株的生长具有显著的促进作用。经分类学鉴定,菌株HNZZ23、HNKF5、HNXX14和HNXX169分别为萎缩芽孢杆菌Bacillus atrophaeuse、短小芽孢杆菌B.pumilus、铜绿假单胞菌Pseudomonas aeruginosa和枯草芽孢杆菌B.subtilis。本研究结果表明,感病花生根际细菌HNZZ23、HNKF5、HNXX14和HNXX169对花生白绢病原菌S.rolfsii具有良好的拮抗作用和生防潜力,可为花生白绢病的生物防治提供优质菌种资源。

贝莱斯芽孢杆菌HYN-9的分离、鉴定及其对花生白绢病的生防作用

本研究旨在分离和鉴定对花生白绢病菌(Sclerotium rolfsii Sacc.)具有高效拮抗作用的细菌菌株。采用稀释涂布平板法从废弃的黄芩药渣中分离到18株细菌,其中菌株HYN-9对S.rolfsii的抑菌活性最强,抑菌带宽度为10.92 mm。基于形态特征、生理生化特征和16S rDNA序列,将菌株HYN-9鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。菌株HYN-9的无菌发酵滤液对S.rolfsii菌丝生长的抑制率为70.01%,并对菌核的形成和萌发也均有较强的抑制作用。此外还发现HYN-9产生的挥发性气体能明显抑制S.rolfsii的生长,抑菌率达88.79%。盆栽试验表明拮抗细菌HYN-9能够明显降低花生白绢病的发病率和感病指数,对花生白绢病的防效为73.23%,显著高于接种多菌灵药剂47.62%的防效(P<0.05)。拮抗细菌HYN-9也能提高花生防御酶活性,接种HYN-9后花生叶片的苯丙氨酸酶(PAL)、多酚氧化酶(PPO)和过氧化物酶(POD)活性显著增加,进而增强花生对病害的系统抗性。以上结果表明贝莱斯芽孢杆菌HYN-9对S.rolfsii具有较强的拮抗作用,是一株具有开发应用潜力的花生白绢病生防菌株。

茉莉白绢病发生特点与绿色防控措施

茉莉花茶是我国特有且产量最高的花茶,在国内外市场广受欢迎。但茉莉易受白绢病侵害,各种植区均有发生,白绢病菌主要通过土壤传播,传统化学药剂防治会产生抗性菌株并存在生态环境安全隐患。文章阐述茉莉白绢病的发生特点,总结农业、物理、生物、化学防治技术,形成绿色防控措施,为防控该病及促进茉莉花健康生长提供科学依据和实践指导。

松油醇与d-柠檬烯对花生白绢病菌的生物活性及协同增效作用

为明确植物源松油醇和d-柠檬烯对花生白绢病菌的生物活性和应用潜力,采用菌丝生长速率法测定了松油醇与d-柠檬烯对花生白绢病菌的抑菌活性,室内筛选了对花生白绢病菌抑制效果好的最佳混配比(质量比),并采用共毒系数法和盆栽法评价了二者的协同增效作用。结果表明,松油醇与d-柠檬烯对花生白绢病菌的抑制活性均较强,抑制中浓度(EC_(50))分别为49.23μg/mL和60.87μg/mL。且在500μg/mL和1000μg/mL浓度下,松油醇处理15 d和30 d可完全抑制花生白绢病菌菌丝生长,菌核形成以及菌核再萌发。而相同条件下d-柠檬烯对菌丝生长、菌核形成和菌核萌发无影响。在特定浓度下,松油醇与d-柠檬烯按不同质量比复配均能提高对花生白绢病菌的抑制作用,其中松油醇和d-柠檬烯以1∶4和1∶2复配时增效作用最为显著,共毒系数(CTC)分别为147.87和216.57。盆栽试验结果显示,松油醇和d-柠檬烯以1∶4和1∶2复配的防效均高于单剂。综上,松油醇和D-柠檬烯复配可作为新型植物源杀菌剂进行开发利用。

Identification of Pathogen of Gastrodia elata White Silk Disease

[ Objective] The aim was to identify the pathogen of Gastrodia elata white silk disease and explore prevention and treatment of the disease.[ Method] Infected G. elata, collected from low-mountain regions in Yichang city of Hubei Province, were isolated and purified. Then, Koch＇s Postulate was adopted to inoculate the pathogen. Finally, the identification was carried out according to its biological characteristics. [ Result] The pathogen of white silk disease belongs to weak hyperparasite. Because of its poor direct invasion ability, the pathogen usually invades into host through wound infection. According to its hyphae morphology and pathogenicity, the pathogen of G. elata White Silk Disease has been identified as Sc/erotium ro/fsii Sacc., which belongs to deuteromycotina, hyphomycetes, agonomycetales, fungi of sclerotium genus. [ Conclusion ] The study will provide references for the control of G. elata White Silk Disease caused by S. rolfsii.

我国花生白绢病菌致病力差异

为了解我国花生白绢病病原菌株的致病力差异,本文对分离自不同地域的39个代表菌株进行了田间、室内(离体主茎、侧枝和叶片)接种试验,结果表明所有菌株均对花生具有致病性,但致病力存在显著差异。田间接种花生植株与室内接种离体主茎、侧枝和叶片的病情指数呈显著正相关,同一菌丝融合群的菌株对花生的致病力存在差异。所揭示致病力差异,为花生白绢病的防控、品种合理布局提供了理论基础和技术支持。

花生白绢病研究进展

花生白绢病是世界花生上发生的一种重要土传真菌性病害,近十年来在我国山东、河南、广东、辽宁、江西等主要花生产区发生为害逐年加重,已成为制约花生产量和质量的重要因素。本文对花生白绢病的发生为害、病原菌的生物学特性与变异、病害流行和防治等方面进行综述,并对今后花生白绢病研究提出一些建议,以期为我国花生白绢病研究提供参考。

铁皮石斛茎基部2种主要病害病原菌的分离与鉴定

铁皮石斛茎基部病害是铁皮石斛的重要病害,严重影响铁皮石斛的产量和质量。为了明确引起浙江铁皮石斛茎基部主要病害的病原菌,采集具典型症状的发病植株进行病原菌的分离、纯化、病原菌形态学特征观察、rDNAITS序列分析、致病性试验结合田间症状,明确浙江铁皮石斛茎基部主要病害是由齐整小核菌Sclerotiumrolfsii引起的白绢病和由尖孢镰刀菌Fusarium oxysporum引起的枯萎病。两种病害都侵染茎基部和茎,并最终导致整株死亡,区别是白绢病发病初期病部通常呈水渍状、褪绿、略肿大、有时伴有黄色液体渗出,后腐烂枯死;枯萎病初期茎秆褪绿、萎蔫,后缢缩干枯而死。湿度大时,前者病部遍布白色绢状菌丝体;后者病部出现白色及粉红色霉状物。

解淀粉芽孢杆菌41B-1对花生白绢病的生防效果

本文旨在研究解淀粉芽孢杆菌41B-1对花生白绢病的生物防治效果。采用对峙培养法,测定41B-1对白绢病菌的抑制效果;在温室盆栽条件下,用41B-1发酵菌液对花生进行灌根,然后挑战接种白绢病菌,检测对白绢病的防效。结果表明,41B-1能抑制白绢病菌的菌丝生长速率,破坏菌丝结构,减少菌核数量;41B-1能在培养基质和植株根系内部长期生存,并诱导植株产生防御反应,灌根处理植株对白绢病表现出明显的抗性,防效高达93.9%。因此,41B-1菌株可以作为防治花生白绢病的生防菌剂。

四种杀菌剂对花生白绢病菌的毒力及田间控制作用

采用菌丝生长速率法，测定了戊唑醇、咪鲜胺、咯菌腈和醚菌酯对花生白绢病菌的室内毒力；并通过田间小区试验，比较了四种杀菌剂播种期拌种处理及结荚期灌药处理对该病害的田间控制作用。四种杀菌剂对病原菌菌丝生长均表现出明显的抑制作用，其EC。值分别为0．05、0．03、0．22和0．61mg／L。田间试验表明，四种药剂结荚期灌药处理防效均高于播种期拌种处理。其中，戊唑醇处理的防效相对较高，拌种处理防效为62．91％-74．93％，灌药处理防效达到68．60％～82．87％。各药剂处理具有一定的增产效果，且结荚期灌药处理增产率高于拌种处理，戊唑醇处理增产率最高，达到10．74％～11．55％。

广东省花生白绢病菌的分布和生物学性状研究初报

采用一般调查和定点调查相结合的方法,对广东省花生白绢病的发生危害与分布情况进行了调查,并对花生白绢病菌的形态、生物学性状及其对杀菌剂的敏感性进行了测定。结果表明,广东省各花生产区均有花生白绢病的发生分布,发病率在10%左右,严重的超过50%,对花生生产造成严重损失;花生白绢病菌的菌丝宽度为6.1-8.2μm,菌丝生长速率介于0.8-1.1 mm/h之间,每培养皿(直径9 cm)产生菌核的数量为55-378个,菌核大小范围为0.89-3.54 mm×0.80-2.40 mm,平均大小范围为1.13-2.12 mm×1.06-1.80 mm;每菌核干重为0.4-2.7 mg。杀菌剂离体毒力测定结果表明,己唑醇和戊唑醇对花生白绢病菌具有较好的抑制作用。

白术白绢病病原生物学特性及其防治药剂筛选

白术白绢病菌的菌丝生长和菌核产生最适培养基为PDA，菌丝在pH值3～9范围内均能生长，pH为4．0～6．0时生长最快，pH值为5时菌核产生量最大，菌核在pH值为4．0～9．0均能萌发，pH值为5～7时菌核萌发最适；白术白绢病菌菌丝生长、菌核产生和萌发的最适温度均为30cC；明确了其对不同碳源、氮源的利用情况。菌丝致死温度为55℃，10min，菌核的致死温度为60℃，10min，试验表明甲基立枯灵等9种药剂对白术白绢病菌丝生长有较好的抑制作用，20％甲基立枯灵、50％甲托在田间对白术白绢病有较好的防治效果。