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。

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.

苍耳茎腐病病原菌鉴定及其杀真菌剂室内筛选

【目的】探究引起苍耳茎腐病的一种病原菌,并通过室内抑菌试验挖掘在多菌灵、抑霉唑、腐霉利、噻菌灵、甲基托布津、咯菌腈和咪鲜胺7种杀真菌剂中对病原菌抑制效果最佳的农药品种。【方法】采用菌丝尖端切割法从发病苍耳茎基部分离病原菌,通过科赫氏法则验证苍耳茎腐病病原菌。对病原菌的菌落、菌丝和菌核进行形态特征观察,通过分子生物学PCR技术扩增其ITS和TEF1⁃α序列并克隆测序,进一步分析鉴定病原菌种类,并对苍耳茎腐病病原菌进行室内杀真菌剂的筛选。【结果】分离到的6株病原菌与罗耳阿太菌(Athelia rolfsii)形态特征一致。将其菌丝和菌核分别接种于健康的苍耳茎基部,约1周后实验组出现与田间发病苍耳植株相同的茎腐病病症。NCXS⁃1克隆测序序列与数据库中的多个A.rolfsii菌株的相应序列一致性为100%;所筛选的7种农药杀菌剂中,NCXS⁃1对多菌灵、抑霉唑、腐霉利、噻菌灵和甲基托布津不敏感,而咯菌腈和咪鲜胺对A.rolfsii的菌落生长具有一定的抑制作用,其中以咯菌腈的抑制作用最强,EC_(50)为0.12 mg/L。【结论】明确引起苍耳茎腐病的病原菌为A.rolfsii。7种农药中咯菌腈是抑制苍耳茎腐病病菌生长效果最佳的杀真菌剂。研究结果可为苍耳茎腐病的有效防控提供科学依据。

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。

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。

Athelia rolfsii的β-甘露聚糖酶纯化研究

从发酵培养5 d的产β-甘露聚糖酶的Athelia rolfsii菌株CBS191.62发酵液中经硫酸铵沉淀、琼脂糖凝胶(DEAE Sepharose Fast Flow)层析、羟基磷灰石(Hydroxylapatite)层析和冷冻干燥结晶等步骤,获得了比活提高了15.1倍,分子量为14.7 kD的凝胶电泳均一的β-甘露聚糖酶蛋白样品。

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.

Efficacy Evaluation of 16% Validamycin·thifluzamide SC against Selerotium rolfsii in Dendrobium officinale Kimura et Migo

[Objective] The paper was to understand the control efficacy and the optimal dosage of 16% validamycin？thifluzamide SC on controlling Selerotium rolfsii in Dendrobium officinale Kimura et Migo. [Method] The control efficacy of 16% validamycin·thifluzamide SC against S.rolfsii was determined by spraying agents on the whole plant of D.officinale. The significance of differences was analyzed by Duncan＇s new multiple range test （DMRT）. [Result] The control efficacy of 16% validamycin.thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg was 85.33% at 14 d post spraying, higher than that of control agent 4% validamycin AS sprayed at the dose of 80 mg a.i./kg （78.36%）, and equivalent to that of control agent 240 g/L thifluzamide SC sprayed at the dose of 120 mg a.i./kg （90.60%）. [Conclusion] 16% Validamycin·thifluzamide SC sprayed at the doses of 80-160 mg a.i./kg could effectively control the damage of S.rolfsii in D.officinale, and could be popularized in the production.

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.

响应面优化罗尔夫青霉Penicillium rolfsii HXL产京尼平的发酵条件

罗尔夫青霉(Penicillium?rolfsii)HXL是从玉林土壤中分离筛选出的一株具有转化京尼平苷为京尼平的菌株.该实验旨在通过优化发酵条件提升其京尼平苷转化率.首先,采用单因素方法对接种量、装液量、p H值和发酵温度等因素进行考查,在此基础上进行4因素3水平的响应面实验优化.结果表明:在接种量6%和装液量100 m L/250 m L、p H5.0和发酵温度30℃的条件下,发酵6天,京尼平含量由原来的0.69 mg/m L提高到了9.16 mg/m L,比优化前提高了12.28倍.此条件下理论预测值9.62 mg/m L,验证实验测得为9.16 mg/m L,与预测值接近,说明预测模型可靠性较高,可应用于京尼平发酵条件的优化.

工业大麻花提取物对3种植物病原真菌的抑菌活性

为了探究工业大麻雌花和雄花提取物对植物病原真菌的抑制作用,采用乙醇浸提法,对工业大麻云麻7号、云麻8号、云麻10号3个品种的雌花和雄花分别进行提取,采用菌丝生长速率法测定工业大麻花提取物对辣椒白绢病菌、辣椒炭疽病菌、稻瘟病菌3种植物病原真菌的抑菌活性。结果表明:浓度为1、2、4、8、16 mg/mL的工业大麻花提取物对辣椒白绢病菌、辣椒炭疽病菌和稻瘟病菌均有抑制效果。从对辣椒白绢病抑菌浓度来看,云麻7号雄花提取物的最低EC_(50)值为4.6601 mg/mL,而云麻8号雄花提取物的最高,EC_(50)值达到32.3770 mg/mL;对辣椒炭疽病,云麻7号雌花提取物的浓度最低,EC_(50)值为3.1149 mg/mL,而云麻7号雄花的最高,EC_(50)值达到6.5135 mg/mL;对稻瘟病菌,云麻7号雌花提取物浓度最低,EC_(50)值为4.6310 mg/mL,而云麻8号雄花提取物浓度最高,EC_(50)值达到8.2520 mg/mL。因此,3个品种的工业大麻花提取物对辣椒白绢病菌、辣椒炭疽病菌、稻瘟病菌3种植物病原真菌均具有抑菌活性。

多种杀菌剂对辣椒白绢病防效的综合评价

为了评价防控辣椒白绢病的化学杀菌剂杀菌效果,对7种杀菌剂原药、14种杀菌剂制剂及复配组合的室内生物活性、盆栽和田间防效进行了综合评价。室内生物活性测定结果表明:97%咪鲜胺粉剂、98%咯菌腈粉剂、96%吡唑醚菌酯粉剂原药单剂对辣椒白绢病菌的抑菌效果比较明显,EC50值为0.0006~24.4884 mg·L^(-1);97%恶霉灵粉剂+96%吡唑醚菌酯粉剂原药复配具有明显的增效作用;42%肟菌·戊唑醇悬浮剂、25%吡唑醚菌酯悬浮剂、15%三唑酮可湿性粉剂等8种制剂的EC50值较小,能明显抑制菌丝生长;25%吡唑醚菌酯悬浮剂+42%肟菌·戊唑醇悬浮剂等6种复配剂对辣椒白绢病菌的抑制作用较好,均表现为明显的增效作用。通过盆栽试验筛选得到防效较好的42%肟菌·戊唑醇悬浮剂、15%三唑酮可湿性粉剂、25%吡唑醚菌酯悬浮剂3种制剂及25%吡唑醚菌酯悬浮剂+42%肟菌·戊唑醇悬浮剂、43%戊唑醇悬浮剂+40%五氯硝基苯可湿性粉剂2种复配组合防效最好,防治效果为97.58%~100.00%。经田间试验验证,15%三唑酮可湿性粉剂和25%吡唑醚菌酯悬浮剂+42%肟菌·戊唑醇悬浮剂复配具有明显的防治效果,防效分别为85.81%和82.02%。试验获得防治辣椒白绢病的最优杀菌剂类型为甲氧基丙烯酸酯类和三唑类杀菌剂,其中15%三唑酮可湿性粉剂、25%吡唑醚菌酯悬浮剂+42%肟菌·戊唑醇悬浮剂复配可用于大面积的辣椒白绢病综合防控。

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。

附子白绢病拮抗细菌的分离鉴定及发酵条件优化

【目的】从黄粉甲中分离获得对附子白绢病病原菌具有较好抑制作用的拮抗细菌,为附子白绢病的生物防治提供菌种资源。【方法】以罹病黄粉甲为材料,通过稀释涂布法和平板对峙法分离并筛选对附子白绢病菌具有拮抗作用的细菌,通过形态结构、生理生化特征及16S rDNA序列分析等对拮抗细菌进行种类鉴定;以拮抗细菌发酵液在600 nm波长下的OD值为指标,采用单因素试验的方法对拮抗细菌的培养基组分以及发酵条件进行优化;通过室内盆栽试验明确拮抗细菌对附子白绢病的防治效果。【结果】采用稀释涂布法从罹病黄粉甲中分离获得4株细菌,经平板对峙法筛选获得对附子白绢病菌具有较好拮抗效果的菌株TS1,该菌对齐整小核菌菌丝生长的抑制率可达68.03%。根据菌株TS1的菌落形态结构、生理生化特征及16S rDNA序列分析结果,确定菌株TS1为枯草芽孢杆菌(Bacillus subtilis)。菌株TS1的优化培养基配方:蛋白胨10.0 g/L、酵母浸粉5.0 g/L、麦芽糖15.0 g/L;最佳发酵条件:装液量30 mL、初始接种量0.50%、转速210 r/min、培养温度42℃、初始pH 9、培养时间48 h。室内盆栽保护和治疗试验结果表明,菌株TS1对附子白绢病的平均防治效果分别为49.39%和62.97%。【结论】优化的发酵方案可用于快速、大批量培养菌株TS1菌悬液。菌株TS1对附子白绢病有较好的防治效果,具有开发成附子白绢病生防菌的潜力。

贝莱斯芽孢杆菌ZHX-7的分离鉴定及抑菌促生效果

为获得高效拮抗花生病害的生防微生物,以花生冠腐病菌为指示菌,采用稀释涂布平板法和平板对峙法,从山东莱西采集的花生连作田的病、健株根际土壤样品中筛选到1株高效生防菌株,编号为ZHX-7。结合形态学特征和16S rDNA、gyrB序列分析,确定ZHX-7为贝莱斯芽孢杆菌(Bacillus velezensis)。ZHX-7的菌悬液、无菌发酵液和挥发性气体对花生白绢病菌、基腐病菌、网斑病菌和轮斑病菌菌丝生长的抑制均达到极显著的水平,平板对峙试验表明ZHX-7的菌悬液对花生白绢病菌、基腐病菌、网斑病菌和轮斑病菌的抑菌率分别为64.40%、70.37%、77.43%和65.32%。在以ZHX-7无菌发酵液稀释10倍的PDA培养基上,花生白绢病菌、基腐病菌、网斑病菌和轮斑病菌菌丝的生长抑制率分别为67.81%、52.16%、23.52%和69.93%。双皿对扣试验表明ZHX-7的挥发性气体对花生白绢病菌、基腐病菌、网斑病菌和轮斑病菌的抑菌率分别为86.82%、35.40%、81.70%和44.19%。ZHX-7可产生蛋白酶、纤维素酶和淀粉酶等次级代谢产物;此外,在温室盆栽条件下,ZHX-7有菌发酵液明显促进了花生的生长,同对照相比,鲜质量、干质量分别增加31.24%和26.47%,并且ZHX-7有菌发酵液明显提高了花生对白绢病的抗性,防效达到51.76%。综上所述,本研究筛选获得的一株贝莱斯芽孢杆菌ZHX-7,能够抑制多种花生病原真菌,同时促进花生生长,是一株具有宽广拮抗谱的多功能菌株,具有较好的生防应用潜力。

白绢病研究的文献计量学分析

齐整小核菌(Sclerotium rolfsii)可侵染数百种植物,并导致严重的白绢病(southern blight)病害.为全面了解白绢病研究现状,本文利用CiteSpace软件,对2002—2023年Web of Science核心数据库中该领域的英文文献进行计量学分析.结果显示,白绢病研究涉及多个学科,年度发文量呈上升趋势.发文量较多的国家是印度,美国和中国.印度农业研究理事会是发文量和中心性值最多的机构.A Javaid和H B Singh是发文量最多的作者.白绢病研究热点涉及生物防治、菌核分化机制和S.rolfsii的代谢产物等多个方面.

芝麻白绢病病原菌的分离鉴定及其生物学特性

为了明确芝麻白绢病的病原菌,采用常规组织分离法分离病原菌,依据柯赫法则、形态特征及核糖体基因内转录间隔区(rDNA-ITS)序列进行鉴定,同时检测其部分生物学特性。结果表明:引起芝麻白绢病的病原菌为罗氏阿太菌Athelia rolfsii(无性世代:齐整小核菌Sclerotium rolfsii);该菌适宜生长温度为22～34℃,最适生长温度为31℃;在pH4.0～9.0范围内均可生长,以pH 6.5～7.0生长最好,表明微酸性至中性环境最有利于菌体生长;该菌虽能利用供试的13种碳源和8种氮源进行营养生长,但在以可溶性淀粉、蔗糖、葡萄糖、麦芽糖、L-阿拉伯糖和菊糖分别作为唯一碳源并配以硝酸盐为氮源的生长条件下不产生菌核,而在以葡萄糖为碳源并配以铵盐为氮源的生长条件下可产生菌核。与合成培养基相比,A.rolfsii在天然培养基上生长更好,可形成更多、更大的菌核。