砀山梨炭疽病病原鉴定及其抑菌药剂筛选

【目的】明确近年来严重危害砀山梨的炭疽病病原菌种类,研究常用杀菌剂对致病菌菌丝生长、分生孢子萌发的抑制作用。【方法】对6个取自不同梨品种上的病果、病叶样本分别进行发病组织培养、单孢分离纯化,根据病原菌的形态特征和致病性,并结合其rDNA-ITS序列分析,进行病原菌种类鉴定。采用常用杀菌剂分别对病原菌菌丝和分生孢子进行处理,观测其化学抑制效果。【结果】从不同病斑上分离出了6个纯化菌株,其形态特征相同,且与已报道的炭疽病菌(Colletotrichum spp.)形态特征相似;用上述纯培养菌株接种于健康果实和叶片上,又引起与田间原标本相同的病害症状;通过病原菌rDNA-ITS克隆测序、BLASTn比对分析,6个菌株为同一致病菌,且该致病菌与台湾枣(Taiwan jujube)炭疽菌株(Colletotrichum sp.EXMQ-1;登录号FJ233185)、日本超市水果(Japanese fruit)炭疽菌株(Glomerella cingulata;登录号AB219012)和凤梨草莓(Fragaria ananassa)炭疽菌株(C.gloeosporioides;登录号EU200455)的rDNA-ITS序列一致;430g·L-1戊唑醇水悬浮剂等7种杀菌剂对病原菌菌丝生长抑制率达100%;70%代森锰锌可湿性粉剂等8种药剂处理,病原菌分生孢子萌发率为0。【结论】危害砀山梨的炭疽病病原菌为半知菌亚门刺盘孢属的胶胞炭疽菌(Colletotrichum gloeosporioides),其有性阶段为围小丛壳(Glomerella cingulata)。常用药剂对该菌菌丝和分生孢子的抑制作用存在着显著的差异。     

一株红棕象甲寄生真菌的分离鉴定

为明确一株红棕象甲寄生真菌的归属,采用形态学及分子生物学方法,从产孢表型、分生孢子特征和ITS序列测定等方面对其进行了分析鉴定。结果表明:该菌分生孢子梗粗短,顶端具2～5个瓶状小梗,分生孢子呈长椭圆形或圆柱形,大小为4.8～9.3μm×2.2～3.1μm;ITS通用引物扩增该菌得到了预期的558bp条带,其与金龟子绿僵菌小孢变种的支持率高达100%。因此,将该红棕象甲寄生真菌菌株鉴定为金龟子绿僵菌小孢变种Metarhiziumanisopliaevar.anisopliae。     

Characterization and pathogenicity of Rhizoctonia isolates associated with cauliflower in Belgium

Sixty-two isolates of Rhizoctonia spp. were collected from Belgian cauliflower fields during 2005 and 2006. The majority of the isolates (60 out of 62) had multinucleate cells and were identified as Rhizoctonia solani . Characterization of anastomosis groups (AGs) was performed using pectic zymograms, PCR-RFLP and sequencing of the rDNA-ITS region. The most prevalent AG was AG 2-1 (55% of isolates), followed by AG 2-1 subset Nt (11%), AG 1-1C (8%), AG 5 (8%), AG 4 HGII (6%), AG 3 (5%) and AG 1-1B (3%). Pathogenic potential towards different vegetable crops and towards maize was determined. Damage to cauliflower and endive was caused by different AGs, with the isolates aggressive towards cauliflower belonging to AG 2-1, AG 2-1 subset Nt, AG 4 HGII, AG 1-1C, AG 1-1B and AG 2-2, and those aggressive towards endive belonging to AG 1-1B, AG 1-1C, AG 2-1 subset Nt, AG 2-2, AG 4 HGII and AG 5. The most aggressive isolates towards bean belonged to AG 2-1 subset Nt and AG 2-2, for lettuce to AG 1-1B and AG 2-1, on carrot to AG 4 HGII and towards maize to AG 2-2. Within the isolates of AG 2-1, variability was observed in PCR-RFLP pattern and in aggressiveness towards several crops, indicating this subgroup to be heterogeneous. This is the first study concerning the occurrence of R. solani AGs causing wirestem in Belgian cauliflower fields and the first report of aggressive isolates of AG 1-1C, AG 2-1 subset Nt and AG 4 HGII associated with cauliflower.     

茄科蔬菜立枯丝核菌的融合群鉴定

 Sixty-five samples were collected from rhizosphere soil, hot pepper and tomato plants showing damping-off, root rot and stem rot in Taian, Shouguang of Shandong province and Zhouzhi, Taibai of Shaanxi province. Thirty-nine Rhizoctonia solani isolates were obtained from these samples. The results of anastomosis group (AG) identification and sequence analysis of 5.8S rDNA-ITS of the isolates showed that thirty-six isolates (92.3%) belonged to AG-4, while only three (7.7%) belonged to AG-5. The isolates of AG4 could further be divided into two subgroups of AG4-HG-Ⅰ and AG4-HG-Ⅲ. The 5.8S rDNA-ITS sequences of the selected isolates of the two subgroups had the 99%-100% identity with standard isolates of AG4-HG-Ⅰ and AG4-HG-Ⅲ (from GenBank). Among the analyzed isolates, AG4-HG-Ⅰ subgroup was the dominant with the frequency of 79.5%. Subgroup AG-4-HG-Ⅲ with the frequency of 12.8% was the second. This is the first report that subgroup AG4-HG-Ⅲ of R. solani isolated from Solanaceae vegetable crops in China.     

Genetic Variation of Host Populations of Liriomyza sativae Blanchard

In this study, partial sequences of the mitochondrial cytochrome oxidase subunit I （mtDNA-COI） gene and the ribosomal internal transcribed spacer 1 （rDNA-ITS 1） gene, isolated from five artificial populations of Liriomyza sativae （Diptera： Agromyzidae）, were sequenced and compared, to analyze their genetic variation. Analysis of the mtDNA-CO1 gene showed that a low genetic variation was detected among the five populations and only five variable sites were found in the nucleotide sequences. Most of the observed variations that occurred within the populations were because of nucleotide transitions, whereas, the interpopulation variation was because of the differences in haplotype frequencies occurring among the host populations. Analysis of the rDNA-ITS1 gene revealed a small diversity in the five host populations. The trend of genetic differentiation in the host populations was consistent with the preference of L. sativae to the plant hosts.     

辽宁地区辣椒疫病菌鉴定及同源性分析

对采集到的辣椒疫病病原菌通过形态学观察和rDNA-ITS序列分析进行鉴定及同源性研究。利用真菌通用引物ITS4、ITS5对病菌基因组进行PCR扩增,将测序结果与已知序列进行比对,并利用Clustalx1.83及MEGA4.0软件进行聚类分析。试验结果表明:病菌菌落为白色,菌丝呈鹅毛绒状,无隔膜,孢子囊卵圆形或梨形,乳突单生;测得病菌ITS序列为805～877bp,rDNA-ITS序列同源性高,致病菌病原均为辣椒疫霉菌(Phytophthora capsici Leonian)。     

九叶青花椒根结线虫病的病原鉴定

为确定四川省蓬溪县九叶青花椒种植区发病植株花椒根结线虫的种类, 进而为九叶青花椒根结线虫病防治提供依据, 本文根据根结线虫雌虫与2龄幼虫的形态特征及雌成虫的会阴花纹、雌虫酯酶同工酶图谱, 并结合特异性扩增及rDNA-ITS扩增, 根据ITS序列构建系统发育树, 对该地区九叶青花椒根结线虫病的病原进行了种类鉴定。结果表明该病原为南方根结线虫Meloidogyne incognita (Kofold & White) Chitwood。这是我国首次在九叶青花椒上发现南方根结线虫。     

灵芝栽培病原真菌的鉴定及异硫氰酸烯丙酯对其抑制效果的研究

为了探究灵芝段木栽培过程中杂菌侵染的主要病原真菌组成及其防控措施,首先对发病灵芝段木及灵芝子实体的病原菌进行分离纯化,采用形态学和rDNA-ITS序列分析进行鉴定,然后研究分离菌株的生物学特性以及异硫氰酸烯丙酯对分离病原菌的抑制效果。结果表明,分离获得的4株病原真菌菌株,其中OTA为黄曲霉(Aspergillus flavus),OTB和OTD为青霉菌(Penicillium infrabuccalum),OTC为木霉菌(Trichoderma sp.)。4株病原菌在PDA培养基生长良好,适宜温度为25~30℃;菌株OTA和OTB的最适碳源分别为木糖和葡萄糖,菌株OTC和OTD的最适碳源为果糖和蔗糖;菌株OTA和OTB的最适氮源分别为牛肉膏和尿素,菌株OTC和OTD的最适氮源为NaNO₃和蛋白胨;菌株OTB、OTC和OTD在酸性条件生长较好,而pH值对菌株OTA的生长影响较小。异硫氰酸烯丙酯对菌株OTA、OTB、OTC和OTD菌丝的生长具有良好的抑制作用,当异硫氰酸烯丙酯浓度为20 μL·L^-1时,其对4株菌株的抑制率均超过97%,可作为安全的防霉剂用于灵芝栽培过程中霉菌污染的防治。本研究结果为灵芝栽培或采后真菌病害的防控提供了理论基础。     

蚕豆赤斑病病原菌分离鉴定及生物学特性研究

采用组织分离法进行病原物的分离、柯赫氏法则进行致病性测定,并利用真菌通用引物ITS1/ITS4和蚕豆葡萄孢特异性引物G3PDHfor/G3PDHrev进行基因组DNA扩增与序列分析,对甘肃省渭源县蚕豆赤斑病的致病菌种类进行研究。结果表明：该病原菌为蚕豆葡萄孢（Botrytis fabae）,系统发育树分析表明该病原菌与GenBank已报道的蚕豆葡萄孢属聚为一类。生物学特性测定表明,该病原菌菌丝生长最适培养基为PDA培养基,最适碳源和氮源分别为乳糖和酵母膏,最适温度为20 ℃,最适pH为8,对光照不敏感。     

马铃薯腐烂茎线虫RPA-LFD可视化快速检测方法的建立

 马铃薯腐烂茎线虫是为害我国甘薯和马铃薯的一种重要植物病原线虫,也是我国重要的检疫性有害生物。为实现对该线虫的准确、快速且可视化的检测,本研究以马铃薯腐烂茎线虫rDNA-ITS序列为靶标构建了重组酶聚合酶结合侧流层析试纸条(RPA-LFD)的可视化快速检测体系。该体系可在39 ℃条件下15 min内特异性地完成对马铃薯腐烂茎线虫的检测,对A型(甘薯种群)和B型(马铃薯种群)单头线虫(J4)的检出底限均为3 125^-1头线虫,可以直接对土壤和甘薯茎中的马铃薯腐烂茎线虫进行检测,灵敏度可达1头(J4)/10 g土壤和1头(J4)/2 g甘薯茎组织。该体系操作简便、成本低廉、结果可视,可为马铃薯腐烂茎线虫的早期预警和口岸检疫提供技术支撑。