白及根腐病病原菌的鉴定及抑制效应研究

为明确鉴定白及块茎腐烂病(根腐病)的病原菌,并筛选能够抑制病原菌的中药材提取物。该研究利用常规组织分离法对病原菌进行分离,通过形态学和分子生物学技术对致病菌株进行鉴定,同时观察了7种中药材提取物对病原菌的抑菌效果。结果表明：(1)从感病叶片、叶鞘及块茎中共分离得到14株真菌和4株细菌,病原菌室内和室外回接表明菌株GF-1致病症状与田间一致,致病率均达到100%。(2)经形态学鉴定,菌株GF-1为附球菌属(Epicoccum)病原菌,菌落白色绒絮状,圆形;菌丝匍匐向外、向上生长,气生,无色,有隔膜,有分枝,具有分生孢子和厚垣孢子。(3)菌株GF-1的ITS序列(全长522 bp)与GenBank中已登录的甘蔗的高粱附球菌(E.sorghinum,MN493119.1)序列一致性最高,达99.62%,与已报道的白及叶斑病致病菌高粱附球菌(E.sorghinum, MF948994.1)的一致性为98.88%。(4)培养基中含有0.1～0.2 g·mL^-1的青钱柳等7种中药材提取物,能够完全抑制GF-1菌落的生长;当培养基中含有0.05 g·mL^-1     

龙牙百合两种病害致病菌的分离、鉴定及抑制效应研究

利用常规组织分离法对广西永福地区种植的龙牙百合两种病害的病原菌进行了分离,并对分离菌株进行培养、纯化、回接和重新分离,最后利用形态学和分子生物学技术对致病菌株进行了鉴定;同时观察了三种植物生长调节物质对两种致病菌的抑制效果。结果表明:两种病害(A和B)症状表明是叶枯病和青霉病,分别从感病叶片中分离得到4株和3株病原菌,病原菌室外回接发现只有菌株A-4和B-2分别致病,致病率均达到100%。形态学鉴定,A-4为葡萄孢属病原菌,菌落白色绒絮状,圆型;菌丝匍匐向外、向上生长、气生,无色,有隔膜,有分枝,具有分生孢子和顶生孢子。B-2为青霉属病原菌,菌落圆形或不规则形,外围形成一圈白色绒毛状,中间蓝绿色;菌丝细,匍匐生长,具横隔,分生孢子梗扫帚状,孢子呈球形。两类菌株分别获得全长522 bp和551 bp的序列,把ITS序列与Genbank中已登陆的序列进行相似性分析,并结合田间致病症状,认为龙牙百合叶枯病致病菌可能是椭圆葡萄孢,而青霉病致病菌是扩展青霉。三种植物生长调节物质对两种致病菌的抑制效果表明,0.1~1.0 mmol·L~(-1)的SA不能完全抑制两种病原菌的生长,而0.5~1.0 mmol·L~(-1)BRs和Me-JA均能完全抑制病原菌A-4和B-2的生长。     

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。     

一种黄秋葵病原真菌的分离鉴定

报道一种在湖南地区发现的黄秋葵花蕾病原真菌。利用PDA培养基分离纯化病原菌株并依据柯赫氏法确定为病害的病原物,通过形态学鉴定和ITS序列分析鉴定病原种类。结果表明,从黄秋葵染病花蕾组织中分离纯化了一种病原真菌,通过形态观察以及ITS序列的比对分析,将该菌株鉴定为棘孢曲霉(Aspergillus aculeatus);其田间接种黄秋葵花蕾的致病率为80%。这是首次报道棘孢曲霉是黄秋葵花蕾病害的病原菌。     

一株苹果树腐烂病病原菌的分离与初步鉴定

苹果树腐烂病已成为严重影响甘肃产区苹果产量和品质的重要病害之一,为确定其致病的致病菌,对采自甘肃省镇原县的苹果树腐烂病病枝,以组织分离和离体枝条接种的方法进行病原菌的分离和致病性测定。结果获得了一株苹果树腐烂病致病菌,通过培养特征、显微形态和rDNA-ITS序列分析综合鉴定及菌体回接实验,初步确定致病菌菌株P1为黑腐皮壳菌(Valsa mali)。     

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。     

虎耳草炭疽病病原菌鉴定

【目的】从虎耳草炭疽病病斑分离病原菌,并对病原菌进行鉴定。【方法】采用柯赫氏法则对从病斑组织块分离的病原菌进行验证,通过形态学结合多基因分子系统学方法对病原菌进行鉴定。【结果】从虎耳草炭疽病病斑分离到2株菌株(菌株号:LPSU 20120244、LPSU 20120251)。2株菌株孢子均无色,无隔,直、圆柱状,菌株LPSU 20120244孢子(11-25)μm×(5-9)μm,菌株LPSU 20120251孢子(15-25)μm×(5-7)μm。多基因分子系统树中,2株菌株分别与喀斯特炭疽菌(Colletotrichum karstii Y.L.Yang,Zuo Y.Liu,K.D.HydeL.Cai)和江西炭疽菌(C.jiangxiense F.LiuL.Cai)模式菌株聚为一支,支持率均为100%。【结论】形态学及多基因分子系统学分析表明菌株LPSU 20120244为喀斯特炭疽菌,菌株LPSU 20120251为江西炭疽菌。     

新疆石河子地区甜樱桃采后腐烂致病真菌的分离鉴定

【背景】甜樱桃果实柔软多汁,采后腐烂率高。石河子是新疆新兴的甜樱桃种植地区之一,但由于采后储运不当造成巨大的经济损失。【目的】鉴定石河子地区的甜樱桃果实腐烂病原菌,以期提高该地区甜樱桃的采后品质、延长货架期。【方法】从石河子136团种植的甜樱桃腐坏组织中分离真菌菌株,根据柯赫氏法则将分离得到的菌株重新接种到健康的甜樱桃果实上确定其致病性;结合形态学和真菌核糖体转录间隔区(r DNA-ITS)序列分析对致病真菌进行鉴定。【结果】从石河子地区甜樱桃腐烂的果肉中分离出5类丝状真菌,其中3类是甜樱桃果实的致病真菌,转录间隔区序列比对确定3类真菌中代表菌株分别为易脆毛霉(Mucorfragilis)、镰刀菌(Fusariumsp.)和干酪青霉(Penicillium camemberti)。【结论】导致新疆石河子地区甜樱桃果实腐烂的致病真菌主要有易脆毛霉(Mucor fragilis)、镰刀菌(Fusarium sp.)和干酪青霉(Penicillium camemberti)。     

具多氯联苯降解特性绦柳内生菌的分离筛选及其移除性能

从室外生长的绦柳和绦柳组培苗中共分离纯化出12株不同的内生菌。通过利用Aroclor 1242为唯一碳源生长试验筛选出生长良好的菌株CGL-1。经菌落形态学、细胞形态学和16S r DNA序列同源性分析,菌株CGL-1为肠杆菌属。通过改变菌株的移除条件(接菌量、p H、盐含量)可知,菌株CGL-1最适移除Aroclor 1242接菌量为10%,p H为7。在此条件下,利用气相色谱(GC-ECD)检测菌株CGL-1对Aroclor 1242的移除效果,发现菌株CGL-1对Aroclor 1242中的每个组分都有明显的移除作用,7 d总移除率为43.2%。     

浙江1株水稻细菌性条斑病菌株的分离鉴定

细菌性条斑病(简称细条病)是水稻的重要病害之一,随着气候的变暖,某些水稻品种有逐年发生加重的趋势,对产量影响较大。2013年浙江省金华市部分水稻种植区域发生细条病,发病严重的田块减产30%以上。采用组织分离法从发病水稻叶片分离获得6株细菌菌株,选择典型菌株JH01回接水稻幼苗,进行柯赫法则验证。接种后发病症状与自然发病症状一致,并重新分离得到此菌株,证明菌株JH01为水稻细条病的致病菌。通过形态学观察、常规生理生化指标测定、16S rDNA 序列测定和同源性分析,鉴定菌株JH01为稻黄单胞菌水稻致病变种（Xanthomonas oryzae pv. oryzicola,Xoc）。     

Biological control of anthracnose (Colletotrichum gloeosporioides) in yam by Streptomyces sp.MJM5763

Aim: To find a suitable biocontrol agent for yam anthracnose caused by Colletotrichum gloeosporioides. Methods and Results: An actinobacterial strain, MJM5763, showing strong antifungal activity, multiple biocontrol and plant growth‐promoting traits was isolated from a yam cultivation field in Yeoju, South Korea. Based on morphological and physiological characteristics and analysis of the 16S rDNA sequence, strain MJM5763 was identified as a novel strain of Streptomyces and was designated as Streptomyces sp. MJM5763. Treatment with MJM5763 and the crude culture filtrate extract (CCFE) was effective in suppressing anthracnose in detached yam leaves in vitro and reduced incidence and severity of anthracnose in yam plants under greenhouse conditions. The CCFE treatment was the most effective of all the treatments and reduced the anthracnose severity by 85–88% and the incidence by 79–81%, 90 days after inoculation with the pathogen. CCFE treatment was also effective under field conditions and showed a reduction of 86 and 75% of anthracnose severity and incidence, respectively. Conclusion: Streptomyces sp. strain MJM5763 was effective in biocontrolling anthracnose in yam caused by C. gloeosporioides. Significance and Impact of the Study: Streptomyces sp. MJM5763 is a potential alternative to chemical fungicides for reducing yield losses to anthracnose in yam.     

昆虫肠道木霉及其对芒果炭疽病菌拮抗作用

为获得优良生防木霉菌株,本研究以昆虫肠道为样本,从中分离鉴定木霉菌株,并以芒果炭疽病菌盘长孢状刺盘孢为靶标菌,通过对峙培养、挥发性物质和非挥发性物质筛选拮抗效果最优的木霉菌株,测定其孢子悬浮液对芒果炭疽病的室内防效研究.结果 显示,从105份昆虫肠道中共分离获得10株木霉,通过形态学特征和Tef1-Rpb2双基因联合建...     

生防细菌T132的鉴定及其对采后柑橘炭疽病的抑制效果

【目的】柑橘(Citri)是世界上重要的果树。由胶孢炭疽菌[Colletotrichum gloeosporioides(Penz.)]引起的柑橘炭疽病是柑橘生产的主要病害之一。为探索对采后柑橘炭疽病有效的生防措施,分离鉴定柑橘根围土壤中一株细菌T132,并研究其特性及生防效果。【方法】根据菌株T132的形态特征、生理生化特性以及16S rDNA序列对其进行鉴定;通过连续8次在人工培养基上传代培养,测定该菌株的遗传稳定性;采用柑橘果实刺伤挑战接种和拮抗菌液直接浸泡健康果实两种方法研究该菌株对柑橘炭疽病的抑菌防病效果;利用洋葱伯克霍尔德氏菌致病因子的特异性引物检测菌株T132是否为潜在的人类致病菌。【结果】菌株T132鉴定为越南伯克霍尔德氏菌(Burkholderia vietnamiensis)。连续8次在人工培养基上传代培养,菌株T132抑制胶孢炭疽病菌生长的能力没有发生明显改变。菌株T132对胶孢炭疽菌C.gloeosporioides引起的柑橘炭疽病有明显的防治作用,刺伤接种的防效为88.2%,自然发病的防效为54.9%。未检测到该拮抗菌株有人体致病相关的洋葱伯克霍尔德氏菌致病因子(BCESM)毒力基因。【结论】首次报道对柑橘采后炭疽病具有生防效果、对人类相对安全的越南伯克霍尔德氏菌生防菌株。     

Integrated control of Colletotrichum gloeosporioides on mango fruit in Taiwan by the combination of Bacillus subtilis and fruit bagging

Anthracnose disease caused by Colletotrichum gloeosporioides in Jingkwang mango grown in Taiwan was significantly reduced by the integration of fruit bagging with either B. subtilis strain LB5 or fungicides. The combined treatments were most effective in reducing early infection during the 2004 season, leading to 56.4 and 58.3% reduction, respectively, while in 2003 reduction accounted for 51 and 52.3%, respectively. Post-harvest application of B. subtilis strain LB5 cell suspensions on fruits already treated by bagging, bagging+LB5 and baggingfungicides in the field reduced anthracnose incidence significantly at all tested concentrations. These results indicate that biocontrol efficacy of B. subtilis LB5 may be due to the prevention of early fruit infection, thereby reducing significantly anthracnose incidence in ripening fruits to much lower levels than those obtained by using a conventional single post-harvest treatment.     

Evaluation of the biological control by the yeast <Emphasis Type="Italic">Torulaspora globosa</Emphasis> against <Emphasis Type="Italic">Colletotrichum sublineolum</Emphasis> in sorghum

The yeasts are microorganisms with great potential for biotechnological applications in diverse areas. The biological control of phytopathogens by yeasts has showed satisfactory results under laboratory conditions, and it has already produced commercial formulations. With this as focus, this work aims to perform in vitro and in vivo evaluations of the action of a Torulaspora globosa yeast strain (1S112), isolated from sugarcane rhizosphere, against the phytopathogenic mold Colletotrichum sublineolum, the causative agent of anthracnose in sorghum. In vitro experiments included the antagonism test in Petri dishes with morphological hyphal evaluation; yeast killer activity; siderophore, volatile compound and hydrolytic enzyme production. In vivo experiments were conducted in greenhouse conditions with a sorghum variety susceptible to C. sublineolum by evaluating the anthracnose disease for 6 weeks. The results indicated that the yeast strain significantly controlled the fungal growth, either in vitro or in vivo. The strain of T. globosa exhibited killer activity against two sensitive strains, which is a novel capacity for this species. The yeast did not produce siderophores, volatile compounds or hydrolytic enzymes, although it has reduced the mycelial growth, resulting in hyphal deformities but not cell death. The yeast controlled the anthracnose disease in sorghum, either inoculated before or after the fungal spores, suggesting that the competition for space and nutrients to dominate the mold and killer toxin production, altering the hyphal morphology, are mechanisms utilized by the yeast in the biocontrol.     

番木瓜果实内生细菌MGP3 菌株的鉴定及拮抗作用

【目的】从番木瓜果皮内筛选具有较强拮抗活性的内生细菌防治番木瓜采后炭疽病和疫霉病,以减少果实采后病害带来的损失。【方法】采用稀释分离和平板抑菌圈法进行内生细菌的分离筛选,结合形态特征、生理生化特性及16S rDNA部分序列同源性分析对菌株进行鉴定,菌株经利福平诱抗处理后田间接种到果树树干上,测定内生菌的定殖动态,采用采前和采后生防试验测定菌株对番木瓜炭疽病和疫霉病的生防效果。【结果】从番木瓜果皮中分离筛选到一株具有拮抗活性的内生细菌MGP3,对10种病原菌有较强的拮抗作用,鉴定该细菌为铜绿假单胞菌(Pseudomonas aeruginosa,登录号JF708186),MGP3可进入番木瓜叶片、叶柄和果皮中定殖。MGP3对采后番木瓜炭疽病和疫霉病的防治效果分别达到50%和71%;除苗期外,采前4个不同时期经MGP3菌液处理可以显著降低采收后果实炭疽菌的潜伏侵染率和炭疽病的病情指数。【结论】番木瓜内生拮抗细菌MGP3具有潜在的生防应用价值。     

Marine yeasts and bacteria as biological control agents against anthracnose on mango

The potential of four yeasts (Debaryomyces hansenii, Rhodotorula minuta, Cryptococcus laurentii and Cryptococcus diffluens) and three bacteria (Bacillus amyloliquefaciens, Bacillus subtilis and Stenotrophomonas rhizophila) with antagonistic capacity against anthracnose caused by Colletotrichum gloeosporioides in mango cv. Ataulfo fruit was investigated. Germination of C. gloeosporioides spores was significantly inhibited by all marine yeasts and bacteria strains of an in vitro test. When yeasts and bacteria were tested on mango fruit, the marine yeast D. hansenii 1R11CB strain and marine bacteria S. rhizophilaKM02 strain were the best antagonists to anthracnose (C. gloeosporioides), which significantly decreased disease incidence by 56% and 89%, respectively, and reduced lesion diameter by 91% and 92%, respectively. All the isolated strains of the phytopathogen, yeasts and bacteria were molecularly identified. Our results from in vitro and in vivo experiments suggest that marine yeasts and bacteria strains can be used as some effective biological control agents for anthracnose in mango.     

Malvidin 3-rutinoside as the pigment responsible for bract color in Curcuma alismatifolia

Malvidin 3-rutinoside was the only anthocyanin identified from pink bracts of Curcuma alismatifolia cultivars. The concentration of malvidin 3-rutinoside in three cultivars increased as the intensity of the pink color in the bracts increased.