A novel pathogen Fusarium cuneirostrum causing common bean(Phaseolus vulgaris)root rot in China

Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.

Studies on the Isolation, Identification and In Vitro Growth Rates of the Three Pathogenic Fungi from Panax notoginseng Cultivated in Wenshan Eparchy

Objective] The aim of this study was to simultaneously isolate and identify the main pathogenic fungi of the root rot, black spot and round spot from the Panax notoginseng plants cultivated in Wenshan Eparchy of Yunnan Province of China. [Method] The pathogenic fungi were isolated and purified by using potato dextrose agar （PDA） medium. The morphological identification was accomplished first according to the colony forms of the fungi when cultivated in vitro, then accord-ing to the symptom characteristics and colony forms of the re-isolated fungi in the reverse inoculation experiments. The molecular identification was performed accord-ing to the amplification and alignment of the internal transcribed space （ITS） se-quences of the fungi. The increases of the diameters and thickness of the colonies of the fungi cultivated in vitro were employed to indicate the growth rates of the fungi. [Results] The consistency of the colony forms and symptom characteristics and the 96%-99% similarities revealed in the ITS sequence alignments al proved that the main pathogenic fungi of the root rot, black spot and round spot of the P. notoginseng plants raised in Wenshan were Cylindrocarpon didymium, Alternaria panax and Mycocentrospora acerina, respectively. When cultivated in vitro in the same temperature, humidity and il umination, the increases of the colony diameters and thickness of C. didymium were the highest, fol owed by those of A. panax, then those of M. acerina. During different cultivation periods, the differences of the colony diameters and thickness of the three fungi al reached extremely significant level. However, at the same cultivation time, the differences of the diameters and thickness among the three fungi only reached significant level. [Conclusion] The main pathogenic fungi which result in the root rot, black spot and round spot of the P. notoginseng in Wenshan are C. didymium, A. panax and M. acerina, respec-tively. When these three diseases break out at the same time, the root rot wil spread fastest, fol owed orderly by the black spot and the round spot.

Isolation and Identification of Root Rot Fungus of Astragalus membranaceus

The perennial root of Astragalus membranaceus is used as a medicine, while root rot is a main factor causing reduction of quality and commodity value of A. membranaceus . The screening and research of the pathogenic species and their characteristics could provide theoretical and practical basis for the control of this disease. A pathogenic strain was isolated and purified from the root part of four-year-old A. membranaceus , and identified by morphological and molecular biological methods as Fusarium oxysporum . This study will provide a theoretical basis for the research of the biological characteristics and control of F. oxysporum .

Impact of long-term chemical fertilizer and organic amendment to Fusarium root rot of soybean

Soil suppressiveness to Fusarium root rot of soybean had been observed in a black soil field after a long-term fertilization with nitrogen(N)and phosphorus(P)fertilizer combined with pig manure as organic amendment(NPM),rather than that with only nitrogen and phosphorus fertilizer(NP)or no fertilizer(NF).To determine the microbial role on this suppressiveness,fungal and bacterial community characteristics in NPM,NP and NF treatments were investigated by q PCR and DGGE.Compared with the similar bacterial community characteristics among 3 treatments,fungal community,especially Fusarium population size and community composition in NPM treatment were different with those of NP and NF groups.Based on the isolation and pathogenicity test,pathogenic F.oxysporum,F.graminearum,F.verticillioide and F.lateritium absolutely dominated Fusarium community in NF and NP groups.Nonpathogenic F.avenaceum,F.equiseti,F.culmorum,F.redolens,F.solani and F.tricinctum dominated Fusarium community in NPM group.Isolation rate of pathogenic Fusarium in NPM reduced from 100%to 38%in NF.These results suggested that the dominance of soil non-pathogenic Fusarium population induced by organic amendment might play an important role on suppressing Fusarium root rot in the tested field.

Research Advances of Root Rot in Medicago sativa L.

As the most famous perennial leguminous forage in the world, Medicago sativa L. ranks the first in both yield and nutritional value, and can be used for many years once planted in field production. However, root rot has become a very important reason for yield decrease and plant de-cline of alfalfa due to long service life. According to the research progress at home and abroad, the main pathogen distribution, harms and control methods of root rot in M. sativa at home and abroad were systematically expounded, in order to provide a theoretical basis for further research of the disease.

湖南烟草镰刀菌根腐病病原鉴定及防治药剂筛选

为明确湖南郴州和永州地区烟草根腐病的病原种类,针对主要病原菌筛选有效的防治药剂,分别利用组织分离法和平板稀释法对两地主要烟区采集的烟草根腐病病样和根际土壤进行病原分离,通过形态学观察、翻译延伸因子1A(EF-1α)序列进化分析以及致病性测定确定病原种类,采用生长速率法测定供试杀菌剂对主要病原菌菌丝生长的抑制效果,并通过活体盆栽防效试验验证候选杀菌剂对主要病原菌的防治效果。共分离到真菌128株,其中镰刀菌87株,包括共享镰刀菌Fusarium commune、甜瓜镰刀菌Fusarium incarnatum、藤仓镰刀菌Fusarium fujikuroi、茄镰刀菌Fusarium solani、层出镰刀菌Fusarium proliferatum、Fusarium falciforme、Fusarium humuli共7个种。其中,F.commune占比最高,为39.08%,其次为F.solani和F.incarnatum,占比均为14.94%。致病力测定结果表明,这些菌株都能引起烟草发病,明确其为烟草根腐病的病原物。F.commune对40%咪鲜胺EW、43 g/L戊唑醇SC和15%氰烯菌酯SC高度敏感,EC50分别为0.026、0.079和0.169μg/mL。盆栽试验结果表明,40%咪鲜胺EW的防治效果最为显著,相对防效达到94.43%±2.79%,其次为43 g/L戊唑醇SC和15%氰烯菌酯SC,相对防效为88.63%±1.68%和83.07%±2.55%。本研究表明,湖南郴州和永州地区烟草镰刀菌根腐病病原真菌以共享镰刀为主,供试药剂中,40%咪鲜胺EW对该病原菌的抑菌效果最好。

镰孢菌引发的大豆根腐病及其生物防治研究进展

大豆是我国主要粮食和经济作物之一,但其产量和品质极易受病害影响。大豆根腐病是世界范围内较为常见的大豆病害类型。镰孢菌(Fusarium)是大豆根腐病的主要致病菌之一。本文综述了由镰孢菌引发的大豆根腐病的发生条件、发病症状及病害影响,并分析了镰孢菌引发大豆根腐病的致病性与发病机理。通过尖孢镰孢菌(F.oxysporum)和禾谷镰孢菌(F.graminearum)的致病性研究发现,镰孢菌属菌株可以通过破坏宿主植物免疫应答系统或分泌真菌毒素破坏植物细胞等方式引发大豆根腐病。同时不同病原菌之间还存在协同互作机制,可通过分泌促侵染关键物质协同逃脱宿主植物防御。本文总结了镰孢菌引发的大豆根腐病的生物防治研究进展。生物防治手段集合多个作用靶点于一体,通过转录组学技术能够揭示生物防治的作用机理,而生防微生物固有的活体属性所带来的应用局限性则可通过与农业田间管理、化学防治相结合等方式加以攻破。本文还对关于大豆根腐病乃至各类农业生产病害的生物防治未来研究方向进行了展望。

贝莱斯芽孢杆菌BQ对党参根腐病病原菌抑制效应初探

将贝莱斯芽孢杆菌(Bacillus velezensis)BQ作为最新发现的潜力生防菌。通过平板对峙、孢子萌发、生防机制和离体防治试验检测该菌株对党参根腐病的防治效果。平板对峙试验表明,贝莱斯芽孢杆菌BQ可明显抑制党参根腐病病原菌尖孢镰孢菌DS的生长,菌丝生长抑制率达50.55%,对峙区菌丝发生明显形变;孢子萌发结果表示,贝莱斯芽孢杆菌BQ的代谢产物能有效抑制病原菌DS的孢子萌发;对贝莱斯芽孢杆菌的生防机制进行初探,贝莱斯芽孢杆菌BQ的代谢产物能引起病原菌DS的细胞膜通透性增加,从而导致核酸内容物释放量增加,细胞破裂至死亡。离体防治结果显示,贝莱斯芽孢杆菌BQ对党参根腐病的治疗效果达到46.13%,预防效果达到了63.62%。可见,贝莱斯芽孢杆菌BQ有防治党参根腐病的潜力,可作为生物防治剂进行开发。

新型苜蓿镰刀菌根腐病病原菌FIESC分离及菌株生物学特性测定

为明确北京市顺义区苜蓿(Medicago sativa L.)镰刀菌根腐病的病原菌种类,本研究采用常规组织分离法对发病苜蓿样品进行病原菌分离纯化;利用形态学特征观察结合多基因序列分析(rDNA-ITS,EF-1α和RPB2)的系统发育树对病原菌进行鉴定,并按照柯赫法则测定菌株致病性;采用菌丝生长速率法,测定强致病镰刀菌的生物学特性及杀菌剂的抑制作用。结果表明,本研究共分离获得26株菌株,7株鉴定为镰刀菌,分别属于Fusarium incarnatum-equiseti species complex(FIESC)中的F.ipomoeae,F.compactum和F.flagelliforme以及锐顶镰刀菌F.acuminatum和腐皮镰刀菌F.solani,其中MsF1(F.ipomoeae)的致病力最强,接种苜蓿幼苗发病的病情指数为64.33。生物学特性测定表明,MsF1在温度30℃、pH值为6~10、低氮条件下最适合生长,可耐受150 g·L^(-1)的NaCl胁迫;异菌脲对其抑制效果不明显,供试浓度下抑制率低于10%,而咯菌腈对其半数效应浓度(Median effect concentration,EC 50)为0.142μg·m·L^(-1)。本研究首次报道FIESC可侵染紫花苜蓿引起镰刀菌根腐病,为苜蓿根腐病的多样性研究和田间有效防治提供科学依据和理论支撑。

10种杀菌剂对德国鸢尾茎腐病菌的室内毒力测定

为筛选适宜的杀菌剂防控德国鸢尾茎腐病,测试亮盾、噁霉灵、瑞至等10种杀菌剂对德国鸢尾茎腐病菌木贼镰刀菌和尖孢镰刀菌的防控效果。结果表明,10种药剂对德国鸢尾茎基腐病病原菌菌丝的生长均有不同程度的抑制作用。其中,抑制效果最好的是解淀粉芽孢杆菌;较好的4种药剂分别为精甲·咯菌腈、噁霉灵、唑醚·甲菌灵、双炔酰菌胺·百菌清,它们对木贼镰刀菌的EC_(50)分别为1.809、61.210、55.570、17.408mg/L,对尖孢镰刀菌的EC_(50)分别为141.9、13.572、39.186、71.251mg/L。

大豆根腐病致病病原菌及其抗性研究进展

文章综述大豆根腐病病原菌鉴定与分布、抗病性鉴定与抗病基因挖掘研究现状,从栽培措施、化学防治、定向育种、生物防治方面总结根腐病防治方法,展望未来研究方向,旨在为提高大豆产量提供科学依据。

浅析黑龙江省大豆根腐病研究现状

大豆根腐病为大豆主要病害之一,具有发病范围广、卵孢子存活时间长、危害重等特点,严重制约黑龙江省大豆产业发展。为提高黑龙江省大豆根腐病防控技术水平,文章综述黑龙江省大豆根腐病致病菌种类及分布、发病症状及特点、抗病品种鉴定及防治措施,以期为黑龙江省大豆根腐病防治及研究提供理论依据,助力黑龙江省大豆产业振兴。

温郁金根茎腐烂病的病原鉴定

在浙江省瑞安市陶山镇温郁金主产区,部分田块温郁金发生大规模倒伏、地下根茎严重腐烂。为明确引起该病害的病原物,利用LB培养基和TTC(2,3,5-氯化三苯基四氮唑)培养基从温郁金腐烂根茎中分离获得细菌菌株JF1,采用灌根法、芽侵染法和根茎侵染法确定该菌株对温郁金的致病性。通过形态学特征观察、生理生化测定、多基因序列(16S rDNA、rpoB、gyrB)系统发育分析,明确引起田间温郁金根茎腐烂的病原菌为桑肠杆菌(Enterobacter mori)。

番茄疫霉根腐病病原菌鉴定及药剂敏感性分析

[目的]番茄是内蒙古自治区重要的优势特色蔬菜,近年来因连年重茬、种植品种单一,土传病害发生率增加,制约着番茄产业的健康发展。2021年8月在内蒙古呼和浩特地区番茄苗期出现了一种茎基部变黑、溢缩,纵切维管束褐变的症状,疑似根腐病,为了明确病原菌的种类并为科学防治提供依据,开展了病原菌鉴定及7种药剂的室内敏感性试验。[方法]通过采集20株发病植株,开展了组织分离及病原菌培养、形态学观察、分子生物学鉴定、生理小种鉴定,柯赫氏法则验证以及防治药剂筛选。[结果]从20份发病植株样本中分离得到10个分离株,菌落白色短绒毛状、光照诱导条件下可产生孢子囊,利用ITS测序并构建系统发育树确定其为辣椒疫霉菌;分离株能够侵染苗期番茄植株,产生疫霉根腐病的典型症状,与田间发病症状一致,验证了柯赫氏法则,说明其为番茄疫霉根腐病的病原菌,并且病原菌中2号生理小种占70%,其余为3号生理小种。此外,室内培养条件下7种常用杀菌剂对辣椒疫霉菌的菌丝生长均有抑制作用,其中烯酰吗啉、甲霜灵和嘧菌酯的抑制效果最好。[结论]侵染内蒙古呼和浩特地区番茄植株的辣椒疫霉菌以2号生理小种为主,2号生理小种的化学防治推荐使用烯酰吗啉、甲霜灵和嘧菌酯,使用药剂防治时注意轮换用药以延缓抗药性的产生。

鄂西北烟草根腐病病原菌的分离及鉴定

镰刀菌属引起的根腐病是烟草的重要病害,根腐病危害严重可导致烟草产品质量和产量出现重大损失。为明确鄂西北烟草根腐病病原,从湖北十堰烟区采集典型症状标本分离病原菌,对其进行了形态学和分子生物学鉴定,结合基因系统发育学分析和致病性验证,确定鄂西北烟草根腐病的病原为尖孢镰刀菌、腐皮镰刀菌、木贼镰刀菌和接骨木镰刀菌。

内蒙古自治区紫花苜蓿根腐病病原菌鉴定

为明确内蒙古自治区紫花苜蓿根腐病的主要病原菌种类,从内蒙古自治区5市12个样点采集紫花苜蓿根腐病病样,采用常规组织分离法对病原菌进行分离与纯化,利用形态学结合ITS和EF-1α基因序列鉴定分离物种类,按照柯赫氏法则测定其致病性。结果显示,5市12个样点共分离出425株真菌,按照菌株的菌落和分生孢子形态,结合基因序列鉴定为5属17种,分别为锐顶镰刀菌(Fusarium acuminatum)、茄病镰刀菌(F. solani)、木贼镰刀菌(F.equiseti)、变红镰刀菌(F. incarnatum)、尖孢镰刀菌(F. oxysporum)、燕麦镰刀菌(F. avenaceum)、轮枝镰刀菌(F.verticillioides)、层出镰刀菌(F. proliferatum)、F. falciforme、F. neocosmosporiellum、三线镰刀菌(F. tricinctum)、F.virguliforme、芬芳镰刀菌(F.redolens)、立枯丝核菌(Rhizoctoniasolani)、织球壳枯萎菌(Plectosphaerella cucumerina)、茎点霉(Phoma medicaginis)和根异茎点霉(Paraphoma radicina),其中轮枝镰刀菌、F. falciforme、F.neocosmosporiellum和F. virguliforme引发苜蓿根腐病在世界范围内首次报道。致病性测定表明,17种真菌均能够引起紫花苜蓿根腐病。紫花苜蓿根腐病可由单一病原菌或2~4种病原菌复合侵染引起,且不同地区的致病种群结构不同,但优势致病种均为锐顶镰刀菌。

基于根表真菌群落与病原菌鉴定探究‘宁杞5号’枸杞根腐病的发生机制

【目的】比较两种植区易感病品种‘宁杞5号’枸杞健康株和患病株的根表真菌群落组成和分离到的腐根真菌,明确‘宁杞5号’根腐病的病原菌,探究两种植区‘宁杞5号’根腐病的发生原因。【方法】采用高通量测序技术研究枸杞根表真菌群落的组成特征,采用组织分离法从两种植区枸杞腐根中分离腐根真菌,基于形态学和ITS、EF-1α基因序列对腐根真菌进行分类学鉴定,依据科赫法则进行致病性研究。【结果】两种植区‘宁杞5号’枸杞健康株和患病株之间的根表真菌群落组成均表现出明显差异,主要体现在患病后镰刀菌属(Fusarium)相对丰度升高,被孢霉属(Mortierella)相对丰度降低,伴随着Fusicolla和Pseudogymnoascus等未知类群丰度增加,而两种植区健康株根表真菌群落结构趋于一致。自QXBZ腐根分离到36株真菌,分别鉴定为尖孢镰刀菌(Fusarium oxysporum)、腐皮镰刀菌(F.solani)、红贝俄式孔菌(Earliella scabrosa)、立枯丝核菌(Rhizoctonia solani)和Penicillium pimiteouiense,自QTBZ腐根分离29株真菌,分别鉴定为尖孢镰刀菌、腐皮镰刀菌、红贝俄式孔菌、粉红黏帚菌(Clonostachys rosea)、P.pimiteouiense、新知镰刀菌(F.andiyazi)、桃色顶孢霉(Acremonium persicinum),其中腐皮镰刀菌的分离频率在两种植区均为最高,尖孢镰刀菌次之。回接实验确定腐皮镰刀菌、尖孢镰刀菌、新知镰刀菌和立枯丝核菌是‘宁杞5号’枸杞根腐病的病原菌,其中新知镰刀菌为新发现的枸杞根腐病病原菌。【结论】‘宁杞5号’根腐病发生主要与根表真菌群落结构改变以及病原菌种类密切相关,与种植区关系不大,F.solani、F.oxysporum、F.andiyazi和R.solani是‘宁杞5号’根腐病的病原菌。

当归根腐病主要病原菌生物学特性及室内毒力测定

为探究当归(Angelica sinensis)根腐病的病原菌种类、生物学特性并筛选其防治药剂。采用常规组织法分离培养病原菌,利用柯赫氏法则验证其致病性,通过形态学和分子生物学相结合的方法进行病原菌的鉴定、生物学特性分析;采用菌丝生长速率法对病原菌进行室内毒力测定。结果表明,当归根腐病菌菌落毛毡状,在三种培养基上大型分生孢子呈镰刀形,大小为(27.5~47.5)μm×(3.8~7.5)μm(n=50),隔膜数1~5;小型分生孢子在PDA和SNA培养基上呈椭圆形、肾型、纺锤形,在CLA培养基上肾型,(3.8~15.0)μm×(2.5~7.5)μm(n=50),隔膜数0~3;厚垣孢子在CLA培养基上呈串生,PDA培养基上呈不规则形,SNA培养基上厚垣孢子着生方式多样,串生、圆形、不规则形,大小为(2.5~3.8)μm×(2.5~5.0)μm(n=50)。EF-1α、RPB1和RPB2联合序列系统发育树表明,该菌为锐顶镰刀菌(Fusarium acuminatum),其最适生长温度为25℃,最适生长初始pH为9,光照对其生长无显著影响。室内毒力测定显示10%苯醚甲环唑(WG)对其抑制效果最好,EC50值为83.71 mg/L。本研究可为当归根腐病病原鉴定及田间药剂防治提供参考。

药用植物根腐病研究进展

根腐病可导致药用植物出现根部腐烂,叶片变黄脱落等现象,严重影响药用植物质量和产量,是制约中药产业发展的重要因素之一。根据近年来药用植物根腐病的研究成果,从根腐病的发病特征、病原菌种类、形态及生物学特性、发病机制、防治等多方面进行综述,以期为进一步解决药用植物根腐病问题提供参考。

赣南设施丝瓜根结线虫种类鉴定及杀线剂对其防效测定

[目的]针对赣南地区设施蔬菜根结线虫病危害严重问题,鉴定赣南地区设施丝瓜根结线虫病病原物种类,明确化学杀线剂对病原物的毒力活性并进行田间防效试验,为丝瓜根结线虫病的防控提供理论支撑。[方法]采用五点取样法采集南康区具有丝瓜根结线虫病典型特征病害样品进行分离、纯化及致病性测定,观察分离物的形态特征,通过rDNA-ITS序列和28S rDNA D2D3序列进行测序分析。以该根结线虫二龄幼虫(J2s)为材料,进行室内毒杀活性测定和田间防效试验。[结果]丝瓜根结线虫分离纯化后进行室内回接,丝瓜产生明显根结,且与自然发病典型特征一致,再分离后得到与接种病原线虫形态特征一致的线虫。该病原线虫的形态特征与南方根结线虫Meloidogyne incognita基本一致,rDNA-ITS序列及28S rDNA D2D3序列与Genebank中M.incognita相似性达99%以上,构建系统发育树发现该病原线虫与M.incognita聚在一支。室内毒力测定结果表明:5%阿维菌素EC对M.incognita毒杀活性最高,24 h时EC_(50)为1.1065 mg·L^(-1),41.7%氟吡菌酰胺SC、11%阿维·噻唑膦GR和20%噻唑膦EW依次减弱,24 h和72 h时EC_(50)分别为1.8919 mg·L^(-1)和0.3552 mg·L^(-1)、5.4762 mg·L^(-1)和3.7078 mg·L^(-1)、39.8616 mg·L^(-1)和32.1498 mg·L^(-1)。田间防效试验结果表明:5%阿维菌素EC和41.7%氟吡菌酰胺SC处理对土壤中根结线虫相对防效分别为70.49%和77.99%,作物根结防治效果分别为58.41%和68.71%,均高于其它处理。[结论]赣南地区设施丝瓜根结线虫病病原物为M.incognita,5%阿维菌素EC和41.7%氟吡菌酰胺SC对M.incognita室内毒力和田间防治效果均较好。