黑老虎枝枯病病原鉴定及其生物学特性

<正>黑老虎[Kadsura coccinea (Lem.) A. C. Smith]又名冷饭团、布福娜,果实含丰富的Vc、Ve及多种微量元素,是山区野果珍品[1]。上世纪末,人们从野外引种试栽,目前在黔东南地区实现了规模化栽培。笔者于2017和2018年调查发现,黑老虎枝枯病在黔东南州各种植基地普遍发生,造成严重损失,但关于黑老虎病害的报道甚少[2,3]。本研究对黑老虎枝枯病的病原菌进行了分离培养、柯赫氏法则验证、形态学特征观察及多基因序列     

楠木枝枯病病原菌鉴定

<正>楠木为我国传统名贵树种,其木质紧密、耐腐蚀性强,能够驱虫美化环境,是建筑、家具、雕刻的首选木料;同时具有净化空气、吸烟滞尘、涵养水源、固土防沙等功能,有着巨大的经济及生态价值。楠木主要包括润楠属(Machilus Nees)以及楠属(Phoebe Nees)植株,均属于濒危树种,在我国境内     

楠木枝枯病病原菌鉴定

Phoebe is a traditional precious tree species in China, which has great economic and ecological value. A new disease twig blight was found in the Phoebe planting area of Zhejiang province. Symptoms usually appear on the base or fork of branches with black swollen epidermis and gradually get worse resulting branch wilting or whole plant death when longitudinal epidermis cracking. The diseased samples were collected in 2017-2018 and the fungal isolate was identified as Lasiodiplodia pseudotheobromae based on morphological characteristics of colony and spore and sequence analysis of ITS region and EF1-α gene. The pathogenicity tests on Phoebe showed that L. pseudotheobromae caused the typical symptoms of twig blight. Koch′s postulates were satisfied following reisolation and identification of the isolate from the infected tissues using the methods described above. This is the first report of Phoebe twig blight caused by L. pseudotheobromae in China.     

珍珠李枝枯病病原鉴定及致病性测定

In order to confirm the pathogen of branch blight on pearl plum and its virulence, 14 samples were collected from Guangxi and Guizhou Province, and 21 isolates were obtained and were identified as Botryosphaeriaceae. The results of colony morphology, conidial observation and molecular identification of internal transcribed spacer region (ITS1-5.8S-ITS2) and the translation elongation factor 1-α (EFl-α) showed that the pathogens of branch blight on pearl plum were Botryosphaeria dothidea (66.67%), Neofusicoccum parvum (19.05%), N. algeriense (9.52%), and Lasiodiplodia pseudotheobromae (4.76%). The pathogenicity of different species of Botryosphaeriaceae was tested by mycelial dishes inoculation, and it was found that typical isolates of the four species were pathogenic, among which L. pseudotheobromae was the most virulent one and B. dothidea was the weakest one. This is the first report that L. pseudotheobromae causes branch blight on pearl plum.     

西葫芦根腐和茎基腐病新病原-露湿拟漆斑菌Paramyrothecium roridum

 2013年12月,甘肃省白银市水川镇日光温室中的西葫芦发生了严重的根腐和茎基腐,部分棚室病株率达50%,从病根和病茎上分离得到拟漆斑菌属真菌3株,病株分出率27.3%。采用胚根和茎基部接种法测定了菌株FG-62对西葫芦的致病性:茎基部接种后27 d,植株开始出现凋萎;接种后40 d,两种接种法的西葫芦苗均呈现严重根腐和茎基腐症状,茎基部接种的西葫芦凋萎株率达30%;从病根和病茎上均可再分离出原接种菌。菌株FG-62在PDA平板上25℃培养14 d,产生大量墨绿色至黑色分生孢子座,分生孢子无色至淡榄黑色,单胞,杆状或腰鼓状,两端钝圆,大小为(7.04~9.15)μm ×(1.97~2.46)μm,聚集的分生孢子呈黑色。BLASTn分析结果显示,菌株FG-62(GenBank 登录号 MK252098)的rDNA-ITS序列与露湿拟漆斑菌Paramyrothecium roridum分离物E-469 (GenBank 登录号KY582183.1)和CBS 357.89(源自模式材料,GenBank 登录号NR_145077.1)的序列相似性分别达99.65%和96.83%。依据病原菌形态学和rDNA-ITS序列,将其鉴定为露湿拟漆斑菌P. roridum (Basionym:Myrothecium roridum)。这是露湿拟漆斑菌引起西葫芦根腐和茎基腐的首次报道。     

拮抗水稻白叶枯病菌链霉菌的筛选、鉴定和防效研究

为寻找水稻白叶枯病天然生防药剂,本研究利用共培养和牛津杯法分离筛选植物根际土壤放线菌,共分离纯化获得65株放线菌菌株.在8株能够拮抗水稻白叶枯病菌Xanthomonas oryzae pv.oryzae(Xoo)放线菌菌株中,Sr-63菌株对水稻白叶枯病菌拮抗能力最强,其发酵液抑菌圈直径为46.4 mm±2.3 mm....     

瓜拟多隔孢引起的砂田西瓜叶疫病

 近年来,甘肃省白银市靖远县的一些砂田西瓜中出现了严重的叶疫病,严重田块病株率超过70%。2018年7月,从靖远县高湾乡罹病西瓜叶片上分离得到拟多隔孢属Stagonosporopsis真菌,病叶检出率达100%。采用离体叶片和植株接种法评价单孢分离菌株XG-3对西瓜和甜瓜的致病性,所有接种处理在24 h内均发病显症而对照未发病,其中发病叶片原接种菌的检出率为100%。菌株XG-3在PDA和OA平板培养基上20和25 ℃培养20 d,未见产孢。在自然感病的西瓜叶片上观察到少量分生孢子器,在人工接种发病的西瓜和甜瓜茎、叶上产生大量分生孢子器和分生孢子:分生孢子器球形至亚球形,大小为(82.4~243.3) μm×(82.4~188.4)μm,分生孢子器具1~2个孔口,孔口直径15.7~27.5 μm;分生孢子无色,0~3个隔膜,杆状、柱状、长椭圆形、花生形及不规则形,直或稍弯曲,分隔处不缢缩或缢缩,大小为(5.2~28.3)μm×(2.2~6.0)μm,分生孢子形态和大小依基质和环境条件的不同而有较大差异。BLASTn分析结果显示,菌株XG-3(GenBank登录号:MW282128)的rDNA-ITS序列与瓜拟多隔孢Sta. cucurbitacearum分离物287ITS(GenBank登录号:AY293804.1)的序列相似性达99.80%。在基于rDNA-ITS构建的系统发育树中,菌株XG-3与Sta. cucurbitacearum聚为一组,与西瓜拟多隔孢Sta. citrulli和木瓜拟多隔孢Sta. caricae区分开来。依据病菌形态学和分子生物学特征,将菌株XG-3鉴定为瓜拟多隔孢Sta. cucurbitacearum [Basionym: Sphaeria cucurbitacearum]。     

引起新疆苹果树枝干黑斑病Diplodia seriata的鉴定

正苹果产业是新疆维吾尔自治区(简称新疆)林果业的支柱产业之一,由于新疆冬季寒冷,夏季干旱少雨,病虫发生率低,打药次数少,天山雪水浇灌,无污染。因而苹果果面光滑细腻、色泽光亮、肉质脆、口感风味极佳。色二孢(Diplodia seriata)是广泛传播的一类病原菌,在藤本类植物中引起枯萎病、溃疡病和果实腐烂[1]。2007年在比利时、荷兰和德国的部分地区发现由色二孢(D. seriata)引起     

醚菌酯对假禾谷镰孢的抑制作用及对小麦茎基腐病的防效研究

 为了明确醚菌酯对假禾谷镰孢的抑制作用,本研究采用菌丝生长速率法和孢子萌发抑制法分别测定了醚菌酯对2019年从河南省13个地市分离的50株假禾谷镰孢的毒力。两种方法结果表明,醚菌酯对供试50株菌株的EC₅₀值范围分别在0.127 3~3.070 9 μg·mL^-1和0.001 3~0.070 9 μg·mL^-1,平均EC₅₀值为(1.304 1±0.804 2)μg·mL^-1和(0.017 4±0.017 0)μg·mL^-1。敏感性频率分布图显示,两种方法分别有80％(40株)和70％(35株)的菌株敏感性频率呈正态分布,其平均EC₅₀值分别为(1.135 2±0.531 2)μg·mL^-1和(0.011 4±0.006 3)μg·mL^-1,可作为假禾谷镰孢对醚菌酯的敏感性基线。方差分析结果表明,同一县市的假禾谷镰孢对醚菌酯的敏感性差异较大,EC₅₀值变化范围为0.545 2~2.156 4 μg·mL^-1和0.001 9~0.036 7 μg·mL^-1。聚类分析结果显示,河南省假禾谷镰孢对醚菌酯敏感性差异与菌株的地理来源无明显关联性。温室防效结果显示,小麦种子与醚菌酯悬浮种衣剂进行拌种处理可以起到一定防治效果,0.42 μL AI/2g处理防效最高,防治效果可达50.33％。本研究结果可为河南省假禾谷镰孢对醚菌酯的敏感性监测提供信息,同时为醚菌酯对小麦茎基腐病的防治提供理论依据。     

利用Tri8基因区分中国小麦赤霉病菌的毒素化学型

由镰孢菌(Fusarium spp.)引起的小麦赤霉病在全世界均有发生,我国小麦赤霉病主要由禾谷镰孢菌复合种(Fusarium graminearum species complex,FGSC)所引起,根据产生单族毒素种类分为三种化学型,分别为3-乙酰脱氧雪腐镰孢菌烯醇(3-AcDON)、15-乙酰脱氧雪腐镰孢菌烯醇(15-AcDON)和雪腐镰孢菌烯醇(NIV)化学型。为了更方便地对禾谷镰孢菌复合种进行化学型的区分,本研究利用三对引物分别扩增了三种化学型菌株的Tri8基因并进行了序列测定,根据不同化学型菌株的基因序列差异,进行了特异性引物设计和筛选。利用设计的引物同时扩增三种化学型的Tri8基因并用AvaI内切酶进行酶切,根据酶切片段的大小区分三种化学型。研究表明该方法可准确有效地区分我国小麦赤霉病菌的化学型。