黑龙江省大豆镰孢根腐病菌鉴定及致病力分析

对黑龙江省不同区域采集的大豆根腐病病原种类进行鉴定,结果表明：分离的296个真菌分离物分属于10个种,分别为尖镰孢（Fusarium oxysporum）、茄镰孢（F.solani）、木贼镰孢（F.equiseti）、轮枝镰孢（F.verticillioides）、半裸镰孢（F.semitectum）、大豆拟茎点种腐病菌（Phomopsis longicolla）、瓜果腐霉（Pythium aphanidematum）、茄丝核菌（Rhizoctonia solani）、禾谷镰孢（F.graminearum）、厚垣镰孢（F.chlamydosporum）,各分离物分离频率分别为68.24%、7.09%、5.41%、4.05%、3.38%、3.38%、3.04%、2.70%、2.03%和0.68%。利用‘合丰25’测定所有镰孢菌分离物的致病力,病情指数在30以上的分离物占镰孢菌总数的23.42％,其中尖镰孢为18.22％。在中等以上（病情指数＞30）致病力镰孢菌分离物中,尖镰孢占77.78%。黑龙江省不同地理区域均有致病力较强的分离物,分布不均匀。大豆花芽分化期分离的致病力较强,尖镰孢出现频率比鼓粒期大。本研究为大豆根腐病的田间防治和抗源筛选的研究奠定了基础。     

大豆枯萎病菌尖孢镰孢遗传多样性及大豆品种抗性

 了解大豆枯萎病菌的群体遗传特征及明确大豆种质对大豆枯萎病的抗性,对抗病育种、抗性品种的合理布局以及制定更有效的病害防治策略具有重要的参考价值。本研究利用随机扩增多态性DNA(random amplified polymorphic DNA,RAPD),对采自我国不同地区的大豆枯萎病菌—尖孢镰孢菌(Fusarium oxysporum)进行遗传多样性分析,筛选到10个多态性随机引物,共扩增出75条RAPD条带,其中55条为多态性条带,占73.3%。利用UPGMA法对DNA扩增图谱进行聚类分析,以相似系数0.68为阈值,55个分离物可分为9个遗传聚类组,表明我国大豆枯萎病菌具有丰富的种内遗传多样性,所划分的群体与分离物来源地不相关。同时,对上述分离物进行致病性分析,发现我国的大豆枯萎病菌具有明显的致病力分化现象。进一步利用3个代表性分离物对来自我国不同大豆产区的180个大豆品种(资源)进行抗大豆枯萎病鉴定,发现皖豆28、中黄13、中黄51、中作X08076和5D034等5个品种对大豆枯萎病具有良好抗性,占供试材料的2.8%,表明不同大豆品种对枯萎病的抗性存在一定的差异。     

抗、感大豆品种对尖镰孢根腐病菌侵染及毒素的反应

为了进一步明确大豆抗感品种对根腐尖镰孢的抗病机制,通过透射电镜和形态观察分析了尖镰孢(M38)侵染及产生的毒素对抗感大豆品种的影响。研究表明大豆幼苗胚根经粗毒素处理后,抗病品种‘东农56’幼苗胚根生长没有显著差别,但显著抑制了感病品种‘黑农53’胚根的伸长和侧根的生长;尖镰孢毒素高浓度和低浓度(V粗毒素∶V无菌水=1∶0和1∶15)对抗感品种的致萎能力无显著差异,高浓度处理平均萎蔫指数为100,低浓度处理为17.9~18.1左右;但中等浓度(V粗毒素∶V无菌水=1∶1,1∶5,1∶10)对于感病品种的致萎作用更大;同时,发现尖镰孢侵染感病大豆品种根内侵染量要明显多于抗病品种,且感病品种组织中菌丝的直径明显大于抗病品种,都出现很明显的质壁分离和细胞壁加厚的现象。     

引致大豆根腐病的层出镰孢菌分离鉴定及其特性

层出镰孢菌Fusarium proliferatum是瘤座孢科镰刀菌属的重要植物病原真菌,可侵染水稻、小麦、玉米、芦笋、大蒜、洋葱等作物,引起枯萎病、腐烂病等。2009—2010年,作者在江苏省、安徽省调查大豆病害时,发现层出镰孢菌可侵染大豆而引起大豆根腐病。层出镰孢菌作为大豆根腐病的新病原菌在国内外鲜有报道,所致病害发生特点尚不明确。对层出镰孢菌进行病原鉴定和相关特性研究是病害防控的基础。为此,本试验从大豆根部分离得到层出镰孢菌,对其形态特征和致病性进行研究,并通过ITS序列测定和PRO1/2特异性引物验证,进一步明确其分类地位。     

京津冀设施大棚根际土壤中筛选出的防治根腐病的生防镰孢菌

 由致病性尖孢镰孢菌(Fusarium oxysporum)引起的根腐病严重危害果蔬生产,但非致病性镰孢菌可作为潜在的生防菌。为筛选防治根腐病的非致病生防镰孢菌,从京津冀设施大棚采集茄科、葫芦科果蔬78份根际土样中分离2 402株真菌,筛选出对致病性尖孢镰孢菌(F. oxysporum)具有拮抗效果的真菌173株。利用镰孢菌通用引物进行PCR扩增,从中筛选出28株候选镰孢菌;通过镰孢菌发酵液泡根进行安全性测试,筛选出对寄主黄瓜幼苗安全无害的镰孢菌菌株4株(1418、1441、1436和1473)。进一步通过镰孢菌测序通用引物TEF1αF/TEF1αR结合菌落和分生孢子的形态学特征,1418菌株和1441菌株被鉴定为尖孢镰孢菌(F. oxysporum)、1436菌株被鉴定为茄病镰孢菌(F. solani)。盆栽测试发现,除1441菌株外,1418菌株、1436菌株和1473菌株对黄瓜根腐病的防效均在50%以上,其中1418菌株的防效为70%,与杀菌剂咪酰胺的防效相当,具有很好的应用潜力。本研究筛选获得的具有生防潜力的镰孢菌不仅为镰孢菌致病力分化的研究提供了实验材料,也为新型生防产品的研制奠定了基础。     

大豆根腐病致病镰孢菌的多重PCR检测技术

为建立大豆根腐病镰孢菌的多重PCR检测方法,以四川大豆根腐病致病菌包括尖孢镰孢菌、腐皮镰孢菌、禾谷镰刀菌和木贼镰孢菌为对象,设计镰孢菌翻译延伸因子基因EF-1α的种特异引物,建立多重PCR扩增体系,并进行优化与验证。结果表明:25μL体系为最优镰孢菌多重PCR扩增体系,4种镰孢菌等体积混合DNA 4.0μL,各镰孢菌特异正向引物1.0μL,共用反向引物4.0μL,最佳退火温度为54℃,当循环30次时,能清晰地扩增出各镰孢菌EF-1α条带,对4种镰孢菌混合DNA的检测灵敏度可达0.1 ng/μL。室内环境样本验证结果表明,依据EF-1α扩增片段大小,该体系能够特异地检测出大豆黄化苗与致病镰孢菌混合样本中的镰孢菌,但无法从其它真菌的DNA中扩增获得目的片段。表明基于EF-1α基因特异引物建立的镰孢菌多重PCR检测技术可快速、特异地检测大豆根腐病镰孢菌。     

20%烯·戊·恶种衣剂研制及对大豆镰孢根腐病的防效

为研制一种防治大豆镰孢根腐病的高效、低毒种衣剂,采用菌丝生长速率法测定了96%烯效唑(uniconazole)原药、97%戊唑醇(tebuconazole)原药、98%恶霉灵(hymexazol)原药对引起大豆根腐病的禾谷镰孢、尖镰孢和腐皮镰孢的毒力,筛选最佳复配配比。利用湿研磨法制备种衣剂,并进行室内盆栽苗验证。结果表明:烯效唑、戊唑醇和恶霉灵的配比为3∶1∶16时,对供试3种镰孢菌均表现为增效作用。室内盆栽苗验证试验结果表明,播种前,采用20%烯·戊·恶悬浮种衣剂1.0～2.0 g/kg处理大豆种子对大豆发芽和出苗没有显著影响,并可降低株高,且各浓度处理对大豆尖镰孢和腐皮镰孢根腐病的相对防效均达83.3%以上,对尖镰孢根腐的防效高于5%戊唑醇悬浮种衣剂,对腐皮镰孢和禾谷镰孢根腐病与5%戊唑醇悬浮种衣剂防效相当。本研究开发的20%烯·戊·恶悬浮种衣剂为进一步开展大豆根腐病田间化学防治及推广应用奠定了基础。     

甘肃枸杞镰孢菌根腐病病原鉴定及优势病原菌生物学特性

为了明确甘肃省枸杞根腐病病原种类、生态分布和优势病原菌的生物学特性,于2013年和2014年采集甘肃省各枸杞主产区根腐病患病植株样品,分离纯化后进行形态和分子鉴定,统计分离到的各主产区的病原种类,并对优势病原菌的适宜生长温度、光照条件、pH和碳氮源进行了研究。结果共分离到260株镰孢菌菌株,其中GSJT7-2和GSJY8-1分离频率分别为66.15%和26.92%,属优势种;将2株镰孢菌进行EF-1α基因序列分析及对比,菌株GSJT7-2(登录号:KM457089)与腐皮镰孢菌(Fusarium solani),GSJY8-1(登录号:KM457093)与尖镰孢菌(F.oxysporium)同源性达99%,在系统发育树中聚在一起,分别将它们的分类地位初步确定为腐皮镰孢菌和尖镰孢菌。甘肃各产区病原菌分离种类和频率有较大差异,靖远县以尖镰孢菌为主,占82.89%;其余采集地均以腐皮镰孢菌为主,均占80%以上。腐皮镰孢菌GSJT7-2和尖镰孢菌GSJY8-1在10~40℃内均能生长,最适温度分别为35℃和25℃,最适pH为8~9和8,均在12 h光暗交替条件下生长最快,供试碳氮源中GSJT7-2和GSJY8-1对蔗糖和Na NO3利用效果最好。     

半裸镰孢致病性及苜蓿品种间的抗病性研究

 为探明半裸镰孢对接种后苜蓿种苗的致病性、筛选抗苜蓿根腐病的品种,本研究把4个来源地的9个半裸镰孢分离物接种于14个品种的紫花苜蓿种子,在接种后第14 d测定苜蓿幼苗的相对根长、相对苗高、相对发芽率和病情指数,评价不同苜蓿品种对半裸镰孢的抗病性及病原菌对苜蓿幼苗致病性的相互关系。结果表明:半裸镰孢菌株和苜蓿品种对相对根长、相对苗高、相对发芽率及病情指数均有显著的影响(P<0.05)。病原菌方面,从苜蓿品种THG-1中分离出来的半裸镰孢的致病性最强,从Aohan中分离出来的半裸镰孢的致病性最弱,从WL-323HQ、Sitel和Siriver中分离出来的半裸镰孢的致病性较强,从Reindeer、Legacy和LM400中分离出来的半裸镰孢的致病性较弱;苜蓿品种方面,Algonguin的抗病性最强,Phabulous的抗病性最弱,Verna、Victoria、Hunter river和Amerimultileaf的抗病性较强,WL-323HQ、Sanditi、Sandy和Amerilea721的抗病性较弱。     

黄淮地区大豆根腐病菌分离鉴定及其致病性研究

大豆根腐病是世界大豆产区的重要病害,国内主要分布在山东、安徽及黑龙江等地,是黄淮地区大豆生产的突出问题之一。近几年作者初步调查了山东、安徽、河南及江苏部分地区大豆根腐病的发生状况,并分离鉴定了病原菌,对主要致病菌进行了致病性测定,结果报道如下。 1 材料与方法     

引起黑龙江省大豆根腐病的镰刀菌种类鉴定及致病分析

<正>大豆是黑龙江省四大主要粮食作物之一,种植面积和产量均居全国首位。 大豆根腐病是一种世界性的土传病害[1],主要侵染大豆茎基部至根部,引起根茎腐烂,一般田块减产 10%～30%,重病田块减产达 60%以上,严重时甚至造成绝产[2]。由镰刀菌引起的大豆根腐病是大豆生产上的重要病害 [3]。2017 —2018年,对黑龙江省富裕县、讷河市、五大连池市、北安市、克东县、拜泉县、海伦市、望奎县、林口、牡丹江、尚志、     

Fusarium commune associated with wilt and root rot disease in rice

Wilt and root rot disease in plants has been caused mainly by Fusarium species. Previous studies reported that members of the Fusarium oxysporum species complex (FOSC) were usually associated with this disease, but there has been no report of it being caused in rice by specific Fusarium species. However, in this study, Fusarium commune was identified and characterized as a causal agent of wilt and root rot disease of rice. Four Fusarium isolates (BD005R, BD014R, BD019R, and BD020R) were obtained from different parts (root, stem, and seeds) of diseased rice plants. In morphological studies, these isolates produced key characteristics of F. commune, such as long and slender monophialides, polyphialides, and abundant chlamydospores. In molecular studies, the isolates were identified as F. commune based on sequences of the translation elongation factor 1-α (TEF1) gene that had 99.7%–100% sequence identity with the reference strain F. commune NRRL 28058. The phylogenetic tree showed that all four isolates belonged to the F. commune clade. A mating type test determined that three isolates carried MAT1-2. Their teleomorph stage was still unknown. Pathogenicity assays showed that all the isolates produced wilt and root rot symptoms and the isolate BD019R was observed as the most virulent among the isolates. To our knowledge, this is the first report of F. commune causing wilt and root rot disease on rice.     

Molecular identification and pathogenicity of Fusarium and Alternaria species associated with root rot disease of wolfberry in Gansu and Ningxia provinces,China

Wolfberry (Lycium barbarum) ranks in the top 10 best-selling medicinal plants in China and it has been used for centuries as a medicine and a food supplement. It is suggested to have benefits on human health due to the rich content of polysaccharides, carotenoids, flavonoids, and alkaloids contained in its fruits, leaves, and root bark. Recently, severe root rot diseases have been causing plant losses in major growing areas. Here, we report fungi causing root rot disease in Chinese wolfberry plants. The analysis of nucleotide sequences of the internal transcribed spacer (ITS) region revealed a total of 92 isolates isolated from both soil and plant material samples. Fusarium spp. were the most abundant (58%), followed by Penicillium spp. (9%), and Alternaria spp. (5%). Fusarium spp. included F. oxysporum (36%), F. solani (30%), F. chlamydosporum (9%), F. nematophilum (9%), and F. tricinctum (8%). Sequences from the translation elongation factor 1-α gene (TEF-1α) were used to confirm the identity of Fusarium spp. and showed the predominance of F. oxysporum and F. solani. To confirm the pathogenicity of isolates, four isolates belonging to Fusarium spp. and one isolate belonging to Alternaria spp., isolated from wolfberry root tissues with root rot symptoms, were tested in outdoor and laboratory conditions. Results revealed that the five tested isolates were pathogenic with varying degrees of aggressiveness and ability to induce symptoms of root rot in wolfberry seedlings. The five isolates were recovered from inoculated seedlings, completing Koch's postulates. This is the first report on causative agents of root rot in Chinese wolfberry.     

Identification,pathogenicity and community dynamics of fungi and oomycetes associated with pea root rot in northern France

The pea root rot complex is a major concern for green pea production worldwide. This study aimed at characterizing its composition and dynamics throughout a cropping season in northern France. To this end, fungi and oomycetes were isolated from green pea plant roots with symptoms sampled at the flowering stage in 22 fields in 2017, and at the pea emergence, elongation and flowering stages in two fields in 2018. Out of 646 isolates collected, 317 were identified using molecular markers. Fusarium oxysporum, F. solani and F. redolens were highly predominant. Pathogenicity tests separated the isolates into four aggressiveness groups. F. solani isolates were the most aggressive. Phylogenetic analysis of their TEF1 sequences showed that they mainly belonged to the F. pisi lineage, and that F. oxysporum isolates were genetically close to isolates from the UK that did not belong to the forma specialis pisi. In addition, several Clonostachys rhizophaga isolates are reported for the first time to cause pea root rot. The oomycetes were rarely found and were represented by a few Pythium spp. isolates. Lastly, this study shows that the fungal and oomycete communities associated with pea root rot change during the cropping season. The level of dissimilarity of the root-rot-associated communities decreased throughout the cropping season towards a more similar composition at the flowering stage, dominated by F. solani, F. oxysporum and F. redolens. The proportion of nonpathogenic to weakly pathogenic isolates decreased progressively during the growing season in favour of moderately to highly pathogenic isolates.     

载银无机抗菌制剂对大豆根腐病的防治效果

 测定了广泛用于工业和日用品的载银无机抗菌制剂Zeomic和AM₁对大豆根腐病重要病原菌Fusarium oxysporum、Fusarium solani和Rhizoctonia solani孢子萌发和菌落扩展的抑制作用。结果表明,Zeomic在浓度为500 mg/L时可以完全抑制F. oxysporum和F. solani的孢子萌发,但对F. oxysporum、F. solani和R. solani菌落扩展的抑制作用较弱,分别为7.4%、0.0%和3.7%。AM₁对病菌孢子萌发的抑制作用随浓度的升高而增强,在浓度为250 mg/L时对F. solani孢子萌发的抑制率为18.8%,到1 000 mg/L时可完全抑制。但AM₁在浓度为1 000 mg/L时对F. oxysporum的孢子萌发抑制率只有29.7%,表明不同菌类对AM₁的敏感性不同。同一浓度下的AM₁对F. oxysporum菌落扩展的抑制率大于对F. solani和R. solani菌落扩展的抑制作用,在500 mg/L时对病菌的抑制率分别为51.4%、14.6%和11.0%。温室内对大豆生长的调查结果表明,用种子重量0.05%和0.10%的AM₁拌种对出苗和生长有促进作用,Zeomic用量在0.05%时不影响出苗、株高和根系干物质积累,但当用量增加至0.10%时,则表现对出苗和干物质累积的抑制作用。田间试验结果表明,500m g/L的AM₁拌种对大豆根腐病防效为32.6%,与化学农药35%多克福包衣处理无显著差异,但比后者增产10.1%。由此说明,载银无机抗菌制剂具有用于农作物病害防治的潜力。     

引起河北省保定市白术根腐病的病原镰刀菌种类鉴定

白术(Atractylodes macrocephala Koidz.)是菊科苍术属多年生草本植物,具重要的药用价值和经济效益,而其根腐病在各产区发生普遍.河北省保定地区为白术秧苗的生产基地,一年生白术种植地块根腐病的病株率在5％～20％,二年生地块的病株率达到30％ ～ 50％,造成严重减产.引起白术根腐病的病原菌较...     

大豆疫病的种子处理技术研究

本试验用不同浓度的瑞毒锰锌、杀毒矾和克露进行大豆种子处理试验，结果表明，５００ｐｐｍ瑞毒锰锌对大豆疫病具有很好的治疗作用，而用杀毒矾以种子重量０．４—０．５％的剂量闷种，能显著地抑制大豆疫霉菌的侵入     

北京地区西洋参根腐病病原鉴定及其致病性

根腐病是北京地区栽培西洋参的主要病害之一,为了明确引起该类病害的病原菌,对北京怀柔区罹病西洋参参根进行了病原菌的分离及鉴定。结合形态学以及rDNA ITS区、转录延伸因子TEF 1α区的分子序列特征,对分离菌株的鉴定结果显示,分离频率较高的11个菌株分属于茄镰孢（Fusarium solani）、尖镰孢（F.oxysporum）、三线镰孢（F. tricinctum）、多育镰孢（F. proliferatum）、毁灭柱孢（Cylindrocarpon destructans）。通过柯赫氏法则验证,F. solani和F. oxysporum是引起北京地区栽培西洋参根腐病的主要病原菌;致病性测定结果发现F. solani不同菌株的致病性及致病力表现出明显差异。     

一种新的豇豆根腐病病原菌鉴定及室内药剂筛选

本文对四川成都发生的豇豆根腐病病原菌进行鉴定,为豇豆根腐病的药剂防治提供依据。采集了成都市豇豆种植区豇豆根腐病病株,经常规组织分离并纯化获得116株分离菌株,对分离菌株进行致病性测定、形态学鉴定及rDNA-ITS序列分析。结果表明,分离到的镰孢菌中有10株为Fusarium commune,分离频率为8.62%。对该10株菌进行致病性测定,均为致病菌株;其中MW4-11菌株致病性最强。该致病菌株的最适生长温度为25~30℃,菌丝致死温度为70℃。选用7种杀菌剂通过平皿培养法对MW4-11菌株进行室内毒力测定。结果表明,75%肟菌·戊唑醇水分散粒剂对该致病菌株的毒性最强,EC50为0.030μg/mL。