昆明美人蕉黑斑病菌——链格孢Alternaria alternata

美人蕉是重要的园林绿化植物和生物资源。为了明确美人蕉黑斑病的病原菌种类,并为病害防治提供理论指导,调查了昆明市美人蕉黑斑病的发生情况,采用组织分离法对病原物进行了分离和纯化,并进行了致病性测定。通过形态学和rDNA ITS序列分析,将昆明美人蕉黑斑病的病原菌鉴定为链格孢Alternaria alternata。     

福建闽侯福橘黑斑病病原菌的鉴定

柑橘黑斑病是柑橘的重要病害之一。本文通过病原菌的形态特征和致病性,并结合其rDNA-ITS区域序列及柯赫法则,对从福建省福州市闽侯县福橘果上分离的黑斑病病原菌进行了鉴定分析。结果表明:PDA平板上的病原菌菌落生长缓慢,呈圆形凸起;分生孢子器近球形、黑色炭质;分生孢子单孢、无色,呈椭圆形,大小为(7～12)μm×(5～8)μm,分生孢子外包裹一层半透明凝胶状物质。结合序列比对分析结果,最终将分离的福橘果实黑斑病的病原菌鉴定为柑橘球座菌Guig-nardia citricarpa Kiely。本研究为柑橘黑斑病的早期诊断和防治奠定了基础。     

十字花科蔬菜细菌性黑斑病研究概述

文中介绍了十字花科蔬菜细菌性黑斑病的研究进展,主要包括病症、病害分布、病原菌特征、冠毒素及检测技术等,并介绍了十字花科蔬菜细菌性黑斑病的防治对策,从而为十字花科蔬菜的生产提供更关心翔实的理论依据。     

黑龙江省水稻穗褐变病病原菌的分离与鉴定

【背景】黑龙江省水稻穗褐变病发生较普遍,可造成减产和稻米的品质下降。【目的】明确黑龙江省水稻穗褐变病的主要致病菌。【方法】从不同水稻产区采集水稻穗褐变的病样,进行病原菌组织分离和纯化,根据柯赫氏法则确定致病的病原菌,用形态学和分子生物学相结合的方式进行病原菌种类鉴定。【结果】分离出4种主要的菌,进行致病性测定表现出与田间自然发病一致的症状;经形态特征与rDNAITS序列分析将4种病原菌鉴定为禾谷镰孢菌(Fusarium graminearum Schwabe)、链格孢[Alternaria alternata (Fr.) Keissler]、稻黑孢霉(Nigrospora oryzae Petch)、黑附球菌(Epicoccum nigrun Link);不同年度间病原菌的优势菌存在差异。【结论】黑龙江省水稻穗褐变病原真菌的鉴定可为开展病害防治工作提供参考。     

一种六妹羊肚菌的新型柄腐病害

近年来,四川等地种植的六妹羊肚菌先后爆发柄腐病害,造成严重经济损失。本研究对该病害发生情况进行了调查,从四川、河南、甘肃、贵州4个省收集的12份六妹羊肚菌柄腐病子实体,分离纯化得到37株真菌和3株细菌。根据柯赫氏法则,对所有分离纯化得到的疑似病原菌进行了回接试验,最终确定GJB-3菌株为柄腐病的病原菌。经ITS、RPB2和EF1α序列分析,结合菌落形态和显微特征鉴定柄腐病的病原菌为Fusarium nematophilum。本研究为后期羊肚菌生产病害防控提供了有效的基础数据。     

核桃黑斑病拮抗放线菌WMF106的筛选、鉴定及防效

【背景】核桃黑斑病是由2种病原菌引起的细菌性病害,目前缺乏有效的生物防治方法。【目的】从核桃树根际土壤中筛选对核桃黑斑病病原菌具有拮抗效果的放线菌菌株,为该病害生防菌剂的开发提供基础。【方法】采用稀释涂布法分离放线菌,并以病原菌野油菜黄单胞菌(Xanthomonas campestris pv. campestris)和成团泛菌(Pantoea agglomerans)作为指示菌,利用平板对峙法和改良牛津杯法筛选具有高拮抗活性的菌株,通过形态学特征、生理生化特性和16SrRNA基因序列分析确定其分类地位,并测定其无菌发酵液的抗菌谱和室内防效。【结果】筛选到一株对野油菜黄单胞菌和成团泛菌均有较强拮抗作用的放线菌菌株WMF106,该菌株对2种病原菌的抑菌圈直径分别为2.38 cm和1.82 cm,无菌发酵液对2种病原菌的抑菌圈直径分别为1.75 cm和1.55 cm。根据菌株形态学、生理生化特性及16SrRNA基因序列分析,将菌株WMF106鉴定为暗蓝色链霉菌(Streptomyces caeruleatus)。该菌株对尖孢镰刀菌、腐皮镰孢菌、辣椒刺盘孢菌、灰葡萄孢菌、胶孢炭疽菌5种植物病原菌及大肠杆菌、金黄色葡萄球菌、铜绿假单胞菌、白色念珠菌、黑曲霉5种指示菌均有抑制作用,抗菌性能广谱高效,其无菌发酵液原液对离体叶片上由野油菜黄单胞菌和成团泛菌造成的核桃黑斑病防效分别为77.44%和58.33%。【结论】菌株WMF106可作为防治核桃黑斑病的生防材料,具有良好的开发价值和应用前景。     

四川盆地核桃黑斑病病原菌的分离、鉴定与核桃抗病性评价

为鉴定引起四川盆地地区核桃黑斑病的病原菌,采用组织分离法对病原菌进行分离,利用柯赫氏法则验证其致病性,依据菌株形态学和基于16S rDNA基因序列分析对病原菌进行鉴定;同时,利用分离的菌株对18个栽培品种(无性系)进行抗病性评价。结果表明,分离菌株的菌落形态与黄单胞杆菌属(Xanthomonas)相似,其16S rDNA序列与树生黄单胞杆菌(X. arboricola)的(登录号为KP340804.1)同源性高达99%,因此,将引起四川盆地地区核桃黑斑病的病原菌鉴定为树生黄单胞杆菌。18个核桃栽培品种(无性系)的田间侵染发病率和病情指数分别为35.07%～78.57%和17.71%～51.96%,变异系数分别为17.62%和28.78%,并以此为基础评价出5个高抗病品种(无性系)。这为核桃黑斑病致病机理研究和抗病新品种的选育奠定基础。     

河北省苹果园根际土壤中疑似致病镰孢菌种类

为了解引起河北省苹果再植病害的病原菌,在河北省10个地区苹果园中采集土壤样品,在实验室进行病原菌的诱集分离培养,根据形态和分子特征对主要病原菌进行种类鉴定。结果表明,在分离得到的293株真菌中,有116株镰孢菌,为分离频率最高的真菌。在形态学鉴定的基础上,对供试镰孢菌进行了分子鉴定。在基于核糖体基因内转录间隔区（rDNA-ITS）序列与翻译延长因子1α（EF-1α）序列片段构建的系统发育树中,代表菌株分别与GenBank登记的所属菌株聚于同一群。研究结果明确了河北省苹果再植病害的疑似致病镰孢菌,包括：尖孢镰孢Fusarium oxysporum、木贼镰孢F. equiseti、锐顶镰孢F. acuminatum、层出镰孢F. proliferatum和茄腐镰孢F. solani。     

坡向与龄级对新疆野核桃自然保护区野核桃病害的影响

为了解渐危植物新疆野核桃的病害情况,在新疆野核桃自然保护区调查不同坡向、不同龄级野核桃4种病害的患病比例,分析病害种类、病害等级与野核桃胸径及坡向的相关关系。结果表明: 保护区野核桃的主要病害为核桃褐斑病(95.8%)、核桃枯枝病(90.5%)、核桃黑斑病(74.4%)和核桃腐朽病(7.7%)。4个坡向的野核桃均易患核桃褐斑病,阴坡和半阴坡的野核桃易患核桃枯枝病,阳坡和阴坡的野核桃易患核桃黑斑病,半阳坡和半阴坡的野核桃相对易患核桃腐朽病。4个坡向野核桃的4种病害均随病害等级(1～4级)的增加而病株比例减小。4个坡向核桃枯枝病、核桃黑斑病、核桃褐斑病均以中龄树比例最大,其次是老龄树,再次是小树,未见幼苗患病;核桃腐朽病仅发生在老龄树。核桃枯枝病、核桃腐朽病、核桃黑斑病、核桃褐斑病与野核桃的胸径呈显著正相关,核桃黑斑病与坡向呈显著负相关,核桃枯枝病、核桃腐朽病、核桃黑斑病的不同病害等级与胸径和坡向存在相关性。     

贵州半夏块茎腐烂病病原菌的分离与鉴定

【目的】对贵州省半夏块茎腐烂病病原菌进行分离和鉴定,为开发有效的防治技术体系提供依据。【方法】采用组织分离法进行病原菌分离,根据柯氏法则进行致病性测定,结合形态学、生理生化特性和分子生物学方法进行鉴定。【结果】从贵州3个半夏产地患病样品中分离出12株病原细菌和5株病原真菌。经形态学、生理生化特性和分子生物学方法鉴定,12株病原细菌为胡萝卜软腐果胶杆菌胡萝卜软腐亚种;ZJ、Z3病原真菌为尖孢镰刀菌,D3、D5、H1为茄病镰刀菌。【结论】贵州省半夏块茎腐烂病的病原菌有病原细菌和病原真菌。     

应用AFLP技术分析冬枣优良单株选择的遗传基础

为探讨冬枣优良单株选择的遗传基础,本研究收集了河北、山东冬枣优良单株及对照冬枣共52株,以金丝小枣和尖枣做类外对照进行AFLP分子标记研究。实验选用16对M／E引物组合,共扩增出565条带,基于SM相似系数,利用UPGMA法对多态性谱带进行聚类分析,结果表明：冬枣优良单株群体内存在一定的遗传差异,但这种差异小于冬枣与金丝小枣和尖枣间的遗传距离,因此在聚类图中将冬枣、金丝小枣和尖枣分为3类;冬枣优良单株群体在聚类图中分成若干组,其中河北黄骅原始冬枣林古树和源于原始冬枣林的黄骅采穗圃冬枣优良单株,遗传距离相对较远;山东滨州各县的冬枣优良单株和沾化冬枣古树遗传距离较近,但存在个别变异较大的单株。上述结果证实冬枣是一个存在变异的群体、包含不同类型的品系,不同来源的冬枣优良单株存在一定的遗传变异,说明冬枣优良单株的优良性状不完全是立地条件和栽培技术引起的环境饰变,这一研究结果为冬枣的遗传改良和品种内选优提供了理论依据。     

广东花生主要品种对黑腐病菌的抗性水平鉴定

【背景】寄生帚梗柱孢霉是花生黑腐病的病原菌,被我国列为重要的进境植物检疫性有害生物。该病菌2009年已入侵我国广东,造成花生植株基部腐烂而死亡,严重威胁花生生产安全。筛选与种植抗病品种是防控该病害的重要措施。【方法】收集广东推广种植的15个主要花生品种,通过人工接种方法,鉴定这些品种对花生黑腐病菌的抗性水平。【结果】15个供试花生品种中,湛红2号、湛油62等2个品种表现为抗病;湛油75、湛油82、粤油390、粤油410、仲恺花44、仲恺花99、汕油诱1号等7个品种表现为中抗;花育33号、汕油523、汕油辐1号、粤油18、湛油53等5个品种表现为感病;仲恺花332表现为高感。【结论与意义】目前广东生产上推广种植的花生品种多数对黑腐病菌表现为抗病或中抗水平,部分品种表现为感病或高感。该结果可为我省花生品种的推广与布局提供依据。     

Effect of Time of Inoculation with Xanthomonas campestris pv. mangiferaeindicae on Mango Fruits Susceptibility Epiphytic Survival of X. c. pv. mangiferaeindicae on Mango Fruits in Relation to Disease Development

Susceptibility of mango fruits to bacterial black spot disease was related to the stage of fruit development and to climatic factors (rainfall and temperature). The highest percentages of infected fruits occurred when inoculations were performed during the month just before harvest. Wounds and lenticels are effective entry sites for the bacterium. The ability of lenticels to take up bacterial inoculum was estimated using safranin. The susceptibility of lenticels to entry of the pathogen was directly related to the fruit age. X. c. pv. mangiferaeindicae can survive epiphytically on immature mango fruits. Bacterial populations around 10⁵ c.f.u./fruit are commonly detected. Epiphytic X. c. pv. mangiferaeindicae were not detected on symptomless mature fruits. Those resident populations are an important source of inoculum for fruit infection. The number of bacterial spots occurring on the fruits is directly related to epiphytic populations.     

First Report of Dragon Fruit (Hylocereus undatus) Anthracnose Caused by Colletotrichum truncatum in China

Anthracnose disease was detected from dragon fruit (Hylocereus undatus) at a market of Yuanjiang County, Yunnan Province, China. The results of pathogenicity test, morphology studies and sequence analyses based on ITS and β‐tubulin loci indicated that the disease was caused by Colletotrichum truncatum. The pathogen produced elliptic, yellow spots with chlorotic halos on the surface of the fruit, and the lesion become depressed gradually. Grey to black acervuli appeared on the lesion surface in concentric circles later. This is the first report of dragon fruit anthracnose caused by this pathogen in China.     

鸭疫里默氏杆菌流行菌株的分离鉴定及生物学特性

【背景】鸭疫里默氏杆菌(Riemerella anatipestifer,RA)是引起雏鸭、鹅、火鸡等多种家禽、野禽发生传染性浆膜炎的病原,在全世界范围内广泛存在,危害养禽业发展,造成严重的经济损失。【目的】了解国内RA的流行现状,探究该菌的生物学特性,更好地指导防控鸭疫里默氏杆菌病。【方法】对2020-2021年从山东省、河北省、广东省、山西省等地分离的RA疑似菌株进行PCR、生化和血清型鉴定,并根据药物敏感性结果分析耐药现象,根据半数致死量(median lethal dose,LD₅₀)测定结果分析致病力差异。【结果】共鉴定78株RA分离株,其中,血清1型4株、2型21株、10型11株、6型3株、7型17株,1株有交叉凝集现象,21株血清型未定型;药敏结果显示78株分离株对多粘菌素B、磷霉素、克林霉素等的耐药性最强,对头孢拉定、多西环素、呋喃唑酮、氟苯尼考等抗生素最为敏感,并且78株分离株均存在多重耐药性,其中77株耐药5重及以上;动物试验结果显示,RA的分离株致病力普遍较强,而且不同地区分离株、同地区不同分离株之间均存在差异,数株RA分离株的LD₅₀在10⁴-10⁷ CFU不等。【结论】RA在国内流行表现了强致病力及严重耐药情况,本研究结果为更好地预防控制、临床用药及后续致病机制研究提供了参考依据。     

积雪草漆斑病病原鉴定及室内药剂筛选

近年来,在广西各地积雪草种植基地,出现一种为害极重的病害,该病害病原菌主要为害积雪草叶片、叶柄,可致使叶片大面积枯死,该病害发生普遍、侵染期长,严重影响积雪草药材的品质和产量。该研究采用常规组织分离法从积雪草病叶上分离病原菌并根据柯赫氏法则验证其致病性;通过菌落特征、菌株形态及ITS序列分析鉴定病原菌;在室内利用生长速率法测定10种杀菌剂对该菌的抑制活性。结果表明：为害积雪草叶片的病原菌为泛生漆斑菌( Myrothecium inundatum);该菌侵染性强,接种至健康积雪草叶片后24 h即可发病,并迅速扩展引起叶片萎蔫;杀菌剂60％唑醚?代森联水分散粒剂、45％恶霉灵?甲霜可湿性粉剂、1.8％辛菌胺醋酸盐水剂、80％代森锰锌可湿性粉剂室内对积雪草漆斑病病原菌的抑菌率均在98％以上,抑菌效果极强,建议在生产中轮换应用防治积雪草漆斑病。15％咪鲜胺微乳剂、70％甲基硫菌灵可湿性粉剂和10％苯醚菌酯悬浮剂对该病原菌的抑菌率也均在92％以上,抑菌效果良好,在生产中可酌情考虑使用。     

Isolation and Molecular Identification of Colletotrichum gloeosporioides Causing Brown Spot Disease of Camellia oleifera in Hainan of China

Colletotrichum gloeosporioides is an important pathogen that causes widespread brown spot disease on the leaves of the tea‐oil tree (Camellia oleifera) in China. This study was designed to isolate, identify and characterize this fungal pathogen, based on morphology, molecular characteristics and pathogenicity. One pathogenic fungus, named CCG4, was isolated from wild‐type Camellia oleifera of Hainan Province. Colonies were regular circular in shape with 50–60 mm diameter after 5 days of incubation at 28°C on potato dextrose agar (PDA) medium, and woolly with a small amount of jacinth pigment; the colony colour changed from white to black during later stages of infection. The mycelium produced was branched and septate. Conidia were cylindrical‐truncate, oblong‐obtuse to doliform, colourless with 1–2 hyaline oil globules and 4.5–5.3 μm × 7.7–17.5 μm. The sporodochia were cushion‐shaped. The pathogen was identified as Colletotrichum gloeosporioides on the basis of morphological characteristics and internal transcribed spacer sequence, which showed 100% query cover and 99% similarity to the sequence Colletotrichum gloeosporioides JN887341.1 , from a pathogenic fungus known to cause brown spot disease of Camellia oleifera.     

Factors affecting bacterial black spot of mangoes caused by Xanthomonas campestris pv. mangiferaeindicae

Bacterial black spot of mango caused by Xanthomonas campestris by. mangiferaeindicae was found to be essentially a wound pathogen of leaves under glasshouse conditions, with maximum infection occurring at a temperature regime of 22/26 ^oC (night/day). There were significant differences in leaf susceptibility among cultivars, cv. Sensation being less, and cv. Haden more susceptible than cvs Zill and Kent, which agrees with field observations of fruit infection. The organism is a phylloplane resident year round in the field and inoculum levels in the tree canopy affect ultimate fruit infection. The major weather factor affecting fruit infection was rainfall which showed a significant correlation (r = 0–77) with levels of infection after allowing for an approximate 2 wk latent period. Other significant correlations were with a wind/rain index (r = 0–73) and a storm index (r = 0–66). The correlation of disease with the duration of free water was non-significant (r = 0–22).     

An integrated approach with Trichoderma harzianum DGA01 and hot water treatment on control of crown rot disease and retention of overall quality in banana

A biological control of crown rot disease of banana fruit was analysed using an integrated approach combining hot water treatment and Trichoderma harzianum strain DGA01. Treated fruits were stored at 22–25 °C and 90–95% relative humidity for 2 weeks. The bioefficacy of fungal antagonist in vitro towards crown rot-causing pathogens, namely Lasiodiplodia theobromae, Thielaviopsis paradoxa, Colletotrichum musae and Fusarium verticillioides, was enhanced by 11.41% following hot water treatment (50 °C, 20 min). DGA01 germinated on the fruit 48 h after inoculation and parasitised the pathogen. Postharvest application showed that hot water treatment and conidial suspension of DGA01 (10⁶ ml^?1) applied singly performed significantly better than the untreated control in reducing the incidence of crown rot, but were not as effective as the fungicide. The combination of hot water treatment and DGA01 gave 93% control of fruit decay which was comparable with fungicide treatment of 95%. The quality of fruit was markedly improved in hot water treatment + DGA01 as compared to those dipped in fungicide solution. The inconsistencies of single treatments, by DGA01 or hot water dips, in controlling crown rot such as variation in severity of disease among treatments and within a treatment, were lessened by dipping the fruit in DGA01 conidial suspension following hot water treatment.     

Salicylic Acid Enhances Biocontrol Efficacy of the Antagonist Cryptococcus laurentii in Apple Fruit

Biological control and induced resistance are two of the promising approaches to the control of postharvest diseases. This study was conducted to evaluate the efficacy of salicylic acid (SA) alone or in combination with an antagonistic yeast, Cryptococcus laurentii, in controlling the blue mold disease caused by Penicillium expansum on apple fruit wounds. SA alone significantly inhibited the spore germination of P. expansum in vitro when its concentration was increased to 1000 μg ml⁻¹, but it was not effective in controlling the disease in vivo. Simultaneous application of SA and C. laurentii to the wounds on the apple fruit surface showed that SA could improve the efficacy of C. laurentii against P. expansum in a concentration-dependent manner, being most effective at 10 μg ml⁻¹ but less effective at a higher or lower concentrations. Besides reducing the blue mold incidence in the local wound sites, the combination of C. laurentii with SA at 10 μg ml⁻¹ also had a synergistic effect on the induction of fruit resistance to the disease, which might be associated with a rapid increase in peroxidase, phenylalanineamonialyase and lipoxygenase activities. In addition, SA at 100 μg ml⁻¹ or above showed an adverse effect on the growth of C. laurentii in vitro and in vivo, whereas it had no effect when its concentration was decreased to 10 μg ml⁻¹ or lower. This suggested that SA could enhance the biological activity of C. laurentii in apple fruit by inducing resistance to pathogens based on the antagonistic activity of C. laurentii.