玉米尾孢菌、弯孢菌叶斑病严重流行及防治对策

近几年来,由于气候适宜和感病品种多年的大面积种植,导致我国玉米种植区的玉米尾孢菌、弯孢菌叶斑病的危害越来越重,辽宁、河北、河南等地均有发生,尤以辽宁发生最为严重,一般减产10%～20%,个别地块的感病品种几乎绝产,所以必须引起高度重视,应以推广抗病品种为重点,采取合理的品种布局及药剂防治等进行综合防治。     

基于Dickeya dadantii特有标志基因检测甘薯茎腐病菌

 甘薯细菌性茎腐病是由达旦提狄克氏菌(Dickeya dadantii)引起的一种检疫性病害,近年来在我国多地发生,严重威胁我国甘薯产业的发展。建立特异灵敏的检测D. dadantii的方法对于鉴定检疫病原菌、田间监测病原菌和防控病害有重要意义。本研究对Dickeya属菌株的全基因组序列进行比较基因组学分析,筛选到D. dadantii特有的标志基因,针对标志基因设计引物,其中针对编码登录号为WP_077245517未知蛋白基因的1对引物Dad1-F(5′-CATATCAACCAGACCAGCCGTT-3′)和Dad1-R(5′-CGGCCTGCTTTTAAACAACGTATTA-3′)能只从D. dadantii扩增到167 bp目的片段。由此建立了特异灵敏的常规PCR和实时荧光定量PCR检测D. dadantii的方法,为鉴定检疫甘薯茎腐病病原菌和田间监测病害提供了有效方法。     

寄生柑橘的根腐线虫种类鉴定

从福建省的柑橘根部发现根腐线虫侵染,经形态学鉴定有咖啡根腐线虫(Pratylenchus coffeae)和玉米根腐线虫(P.ze-ae),咖啡根腐线虫为优势种。     

Genetic population structure and trichothecene genotypes of Fusarium graminearum isolated from wheat in southern Brazil

A sample of 140 Fusarium graminearum isolates from Rio Grande do Sul, Brazil, representing three populations at least 150 km from one another, were examined for trichothecene genotype based on PCR amplification of portions of the Tri3 and Tri12 genes and a species‐specific (Fg16F/R) primer pair. Genetic diversity was assessed in a sample of 103 F. graminearum lineage 7 (F. graminearum sensu stricto) isolates using amplified fragment length polymorphism (AFLP) markers. The 15‐ADON genotype was dominant, followed by the NIV genotype (2–18% prevalence), across all three populations. All NIV‐type isolates were in lineage 2 (F. meridionale) and all 15‐ADON‐type isolates were in lineage 7. Isolates with the same haplotype were rare and genotypic diversity was uniformly high (≥98% of the count), suggesting that recombination has played a significant role. The number of migrants (N_m) was estimated between 5 and 6 across all loci and all populations, but the high frequency of private alleles (up to 30%) suggests a historical, rather than contemporary, gene flow. Regarding linkage disequilibrium, 0·8, 1·5 and 2·2% of the locus pairs from the three populations were in disequilibrium, which is lower than values reported in other locations. Thus, Brazilian populations differ from those found in Europe, North America and most of Asia in the presence of a significant frequency (7·8%) of isolates of the NIV genotype in lineage 2.     

香蕉品种对香蕉细菌性软腐病的抗性鉴定

由菊欧文氏杆菌香蕉致病变种[Dickeya paradisiaca(原名Pectobacterium chrysanthemi pv.paradisiaca)]引起的香蕉细菌性软腐病是我国新入侵的毁灭性香蕉病害,应用抗病品种将是防治该病害的有效方法.采用离体叶片法和盆栽法相结合的筛选方法对39个香蕉品种进行抗性鉴定,结果表明,供试品种对香蕉细菌性软腐病菌的抗性存在明显差异,其中表现高抗(HR)的品种为‘皇帝蕉’,抗病(R)品种为‘红河矮’,中抗(MR)品种为‘矮脚遁地蕾’和‘龙州中把’.离体和盆栽鉴定结果与品种田间抗病性一致,可有效、快速、准确地筛选出抗病品种.     

Characterization of Dickeya strains isolated from potato grown under hot‐climate conditions

Dickeya strains isolated in Israel in 2006–2010 were characterized by dnaX sequence analysis, pulsed‐field gel electrophoresis (PFGE), biochemical assays and pectolytic activity, and found to be homogeneous: most of them could be classified as ‘Dickeya solani’. Of the 34 strains isolated from imported seed tubers or potato plants grown from imported seed, 32 were typed as ‘D. solani’ and only two were characterized as Dickeya dianthicola. Biovar typing indicated that all ‘D. solani’ strains were biovar 3. ‘Dickeya solani’ strains were most closely related to Dickeya dadantii subsp. dieffenbachiae according to PFGE and dnaX analyses and both species exhibited high pectolytic activity. Expression levels of two putative virulence genes, pelL (encoding a pectic enzyme) and dspE (encoding a type III effector) were significantly induced in ‘D. solani’ strains isolated from potato plants or tubers grown in hot climates such as the Negev region in Israel, compared to those isolated from seed tubers imported from the Netherlands, France or Germany. Results of this study support the hypothesis that ‘D. solani’ strains isolated in Israel are also clonal; however, they appear to be more virulent than strains isolated in Europe.     

玉米灰斑病研究方法：Ⅰ玉米灰斑病菌孢子的培养

为了明确玉米灰斑病菌的产孢条件,将玉米灰斑病菌接种到马铃薯蔗糖（PSA）、燕麦番茄碳酸钙（OTCA）、玉米叶粉碳酸钙（MLPCA）、燕麦粉（OA）、粗面粉(CWPA)等5种培养基上,于25 ℃下培养,测定该菌生长速度、产孢时间和产孢量。结果表明,菌丝在上述培养基上生长速度均较慢,每天平均生长0.33 mm左右,其中以在OA和PSA上生长速度相对较快。基于上述结果,构建了玉米灰斑病菌孢子培养的二级分段培养法,即将菌丝块接种于加有10～15粒直径为5 mm玻璃珠的马铃薯蔗糖（PS）液体培养基三角瓶里,在25 ℃,180 r/min条件下振荡培养15 d,形成菌丝悬液,再取菌丝悬浮液涂布在MLPCA 培养基上,避光培养13 d左右,可获得大量供接种的分生孢子。长期光照促进菌丝生长,不利于孢子的形成,而长期黑暗不利于菌丝生长,但有利于孢子的形成。     

吉林和黑龙江两省玉米北方炭疽病菌群体生物学特性分析

由玉蜀黍球梗孢Kabatiella zeae引起的玉米北方炭疽病在我国东北地区普遍发生,在一些地区已成为玉米生产上的主要病害,严重影响玉米高产稳产,威胁我国粮食安全。为明确玉米北方炭疽病菌群体生物学特性,本研究于2020年7月-10月在吉林和黑龙江两省共17个地点采集了玉米北方炭疽病样品180份,并分离纯化到624个玉米北方炭疽病菌单孢菌株,通过形态学观测,科赫氏法则验证及分子生物学鉴定,确定所分离的病原菌均为Kabatiella zeae。依据菌落产黑色素能力与菌落生长情况将病原菌划分为4种不同菌落形态类型。本研究选择4株代表性菌株SH10-1(类型Ⅰ)、HB10-1(类型Ⅱ)、HN10-1(类型Ⅲ)和NA10-1(类型Ⅳ),对病原菌在两省分布比例、产孢能力、菌落生长速率,产孢方式和致病性等的比较结果显示,类型Ⅰ、类型Ⅱ和类型Ⅲ在两省份病原菌群体总数中占98.8%;类型Ⅳ在两省份中只分离到7株,其生长速率较快。对类型Ⅰ、类型Ⅱ和类型Ⅲ病原菌分析得出结论：产黑色素能力强的病原菌致病性较强且产孢能力较弱。研究结果可为玉米北方炭疽病的防治提供一定参考。     

基于Dickeya dadantii特有标志基因检测甘薯茎腐病菌

 甘薯细菌性茎腐病是由达旦提狄克氏菌(Dickeya dadantii)引起的一种检疫性病害,近年来在我国多地发生,严重威胁我国甘薯产业的发展。建立特异灵敏的检测D. dadantii的方法对于鉴定检疫病原菌、田间监测病原菌和防控病害有重要意义。本研究对Dickeya属菌株的全基因组序列进行比较基因组学分析,筛选到D. dadantii特有的标志基因,针对标志基因设计引物,其中针对编码登录号为WP_077245517未知蛋白基因的1对引物Dad1-F(5′-CATATCAACCAGACCAGCCGTT-3′)和Dad1-R(5′-CGGCCTGCTTTTAAACAACGTATTA-3′)能只从D. dadantii扩增到167 bp目的片段。由此建立了特异灵敏的常规PCR和实时荧光定量PCR检测D. dadantii的方法,为鉴定检疫甘薯茎腐病病原菌和田间监测病害提供了有效方法。