河南省玉米锈病病原菌的分子检测

正玉米锈病是玉米生产中的重要病害,于2004年在河南省首次流行,目前已成为该省玉米生产中的主要病害(袁虹霞等,2010)。该病病原菌在世界范围内有2属3种(谌多仁,1963),我国玉米锈病主要包括由玉米柄锈菌Puccinia sorghi Schweinitz引起的普通型锈病和由多堆柄锈菌P.polysora Underwood引起的南方型锈病,二者从发病症状和病原菌     

甘草叶斑病的发生与病原菌鉴定

近年来,在甘肃省兰州市及渭源地区甘草产区发现一种甘草新病害—甘草叶斑病。2006－2008年对其发病情况进行了调查,甘草叶斑病在6月下旬开始发病,9月中旬为发病高峰期,发病率达80%。高燥地发病率低于低洼地,采用轮作可减轻甘草叶斑病的发生。经过对甘草叶斑病病原菌形态、培养性状和致病性等方面的测定表明,病原菌为豆链格孢（Alternaria azukiae）。通过寄主范围测定表明,该病原菌亦可侵染独活、羌活等药用植物。对大黄、苍耳等不具侵染性。     

胡萝卜软腐果胶杆菌巴西亚种(Pectobacterium carotovorum subsp.brasiliense)引起的黄瓜细菌性软腐病在中国发生

2014—2015年,在中国山东、山西、河北、河南、辽宁等省的黄瓜茎叶上发生了毁灭性的细菌性软腐病,造成了黄瓜产业严重的经济损失。黄瓜叶片、茎、叶柄和果实表面出现流胶;茎基部呈深褐色进而出现湿腐。受侵染的黄瓜叶边缘出现黄斑和湿腐症状,并逐渐扩散至叶片中心。从受侵染组织中分离出45个细菌菌株,在形态学特性鉴定、生理学、生物化学和16Sr RNA基因序列分析的基础上,将病原体鉴定为胡萝卜软腐果胶杆菌(Pectobacterium carotovorum)。多位点序列分析(MLSA)证实,分离菌株是胡萝卜软腐果胶杆菌巴西亚种[Pectobacterium carotovorum subsp.brasiliensis(Pcb)],病原菌归入进化枝II。重新分离获得与原始菌株相同的菌株,证实了分离菌株的致病力。寄主范围测试表明,该菌株具有广泛的寄主范围。目前为止,这是对Pcb引起的黄瓜软腐病——这一对黄瓜生产具有重要经济影响的病害在中国乃至全球范围内的首次报道。     

谷子锈菌巢式PCR检测体系的建立

<正>由粟单胞锈菌(Uromyces setariae-italicae)引起的谷子锈病是一种危害严重的真菌性病害,该病可在短期内大面积流行,通常导致减产10%~30%。谷子锈病病原菌U.setariae-italicae,属担子菌亚门(Basidiomycotina)、柄锈菌科(Pucciniaceae)、单胞锈菌属(Uromyces),是一种多孢型转     

裸仁美洲南瓜叶枯病病原菌鉴定及其寄主范围和侵染条件

近年来,在甘肃省武威地区裸仁美洲南瓜发生了一种叶枯病,采用常规组织分离法对罹病组织进行了病原菌分离培养,以及病原菌的形态、分离培养性状观察和致病性测定.结果表明,引起裸仁美洲南瓜叶枯病的致病菌为瓜链格孢Alternaria cucumerina(E11.et Ev.)E11iott.寄主范围测定表明,该病原菌可侵染所有供试葫芦科植物,其中南瓜、西葫芦和甜瓜发病最严重;丝瓜和苦瓜发病较轻;该病原菌还可引起白菜和菜豆发病.温度和保湿时间对病原菌的侵染影响较大,25～30℃温度范围内最易侵染,病害潜育期仅为2～3天;当保湿时间60h时,病叶率达到88%,而保湿时间为6h时,病叶率仅为8%.南瓜不同品种对叶枯病的抗性差异较大,其中二星、天然、光板1号、无壳(李建民)和金无壳为高抗品种;四星、粒赛金、金大地、郑峰光板、日本南瓜为高感品种.     

甘蔗褐锈病研究进展

由黑头柄锈菌(Puccinia melanocephala)引起的甘蔗褐锈病在世界甘蔗种植区广泛分布,也是我国蔗区发生最普遍、为害最严重的叶部病害。本文从甘蔗褐锈病的分布与为害、病原菌特征与生物学特性、病菌侵染过程、病害发生规律、寄主抗病性以及防治等方面进行了综述,旨在为病害的有效防控提供依据。     

小麦叶锈菌的特异性分子诊断检测技术

小麦叶锈病由Puccinia triticina引起,是我国小麦生产上的重要病害。本研究旨在建立小麦叶锈菌快速、准确的PCR诊断检测技术体系,用于病害精准测报和综合防控。以真菌β-微管蛋白基因的保守序列为引物,进行小麦锈菌gDNA的PCR比较分析,发现小麦叶锈菌具有长度为268bp的特异性DNA片段;序列分析后设计了2对专化性引物,成功获得检测灵敏度为5.00pg/μL模板DNA浓度水平的小麦叶锈菌种的特异性SCAR标记。对55个来自我国不同麦区的小麦叶锈菌标样以及其它麦类病原真菌的检测表明,该叶锈菌标记的检测可靠性达100%。人工接种条件下,叶锈菌侵染24h后,即可在小麦叶片内检测到该标记。     

小豆锈病病原菌鉴定

 小豆锈病是小豆的重要病害。然而,小豆锈病病原菌在我国还没有被鉴定。本文对从黑龙江省和内蒙古自治区采集的5个小豆锈病菌样品的分类地位进行了研究。形态学观察表明,小豆锈病菌夏孢子芽孔位于赤道线或赤道线上方,冬孢子平均壁厚为2.0 μm。分子标记检测发现,小豆锈病菌不能被疣顶单胞锈菌特异性引物对UA-ITSF/UA-ITSR扩增,小豆锈病菌和豇豆锈病菌不能被豇豆单胞锈特异性引物对UV-ITSF/UV-ITSR区分。对豇豆单胞锈特异性引物对扩增的4个小豆锈病菌样品PCR产物进行测序,比对分析表明目标序列与小豆单胞锈ITS序列的同源性为99%~100%。基于夏孢子的芽孔位置、冬孢子壁的厚度、疣顶单胞锈菌及豇豆单胞锈特异性引物检测结果和ITS序列分析,小豆锈病菌被鉴定为小豆单胞锈。     

粟锈病菌夏孢子生活力及寄主范围的研究

 将指形管装的粟锈菌夏孢子和纸袋装的病叶保存在冰箱中,10个月后夏孢子仍有一定的发芽率,用其接种谷子可引起发病。随着保存时间的推移,夏孢子的发芽率及其接种发病程度也降低。寄主范围试验表明,该菌可侵染狗尾草属中的几种狗尾草,但不侵染金色狗尾草。     

华盛顿葵叶斑病菌鉴定及寄主范围研究

通过对华盛顿葵叶斑病发病叶片和叶柄进行病原菌分离、接种及形态观察,表明华盛顿葵叶斑病是由柯氏帚梗柱孢霉(Cylindrocladium colhounii Peerally)引起的。寄主范围测定结果显示,该菌除侵染华盛顿葵外,尚可侵染棕竹、夏威夷椰子、绿巨人、绿萝、鹤望兰及凤眼蓝等其他20种植物。     

Field Resistance to Willow Leaf Rust Melampsora epitea in Inter- and Intraspecific Hybrids of Salix viminalis and S. dasyclados

Families of interspecific hybrids between Salix dasyclados and S. viminalis, and intraspecific hybrids of the two species, were monitored for rust infection caused by Melampsora epitea during the years 1997–1999. The resistance of interspecific hybrids was compared to intraspecific pure species halfsibs. In addition, uredospores were sampled from the most infected interspecific hybrids to determine whether rust from interspecific hybrids differed from the rust spores that infected the pure species. The results from 1997 and 1999 showed that interspecific hybrids were more resistant than the intraspecific pure species, thus exhibiting a pattern of hybrid resistance. In 1998 the interspecific hybrids showed intermediate resistance compared to intraspecific pure species hybrids, i.e., an additive pattern of resistance. The rust sampled from the interspecific hybrids consisted of the same types of rust that infect the pure species. Comparisons of weather conditions prevailing during the three growing seasons indicated that these conditions might play a role in the infection pattern, in addition to the level of sensitivity to infection shown by the plants.     

Genetic Diversity in Relation to Sexual and Asexual Reproduction in Populations of Melampsora larici-epitea

Genetic diversity of Melampsora larici-epitea leaf rust from three cultivated stands of the willow Salix viminalis was studied using AFLP polymorphisms at 60 loci. One population was located in Northern Ireland and two in Sweden. Analysis of molecular variance (AMOVA) showed that most of the genetic variation was distributed on a fine scale within the field in all populations. Both Swedish populations displayed a very high genotypic diversity (normalized Shannon's indices of 0.95 and 1.00) and random association among loci. These results suggested that sexual reproduction had an important influence on the Swedish populations. The occurence of the alternate host (larch) adjacent to one of the Swedish rust populations did not affect the genetic diversity. However, severe rust attacks started earlier in the season in this population. The M. larici-epitea population in Northern Ireland was characterized by a low genotypic diversity (normalized Shannon's index = 0.54) and non-random association among loci was indicated by test of multilocus association and by pairwise tests among loci. These results suggested that asexual reproduction had a major effect on the genetic structure of this population, probably because of the overwintering of asexual spores and/or a population bottleneck associated with the annual sexual phase.     

Relation between leaf rust (<Emphasis Type="Italic">Melampsora epitea</Emphasis>) severity and the specific leaf area in short rotation coppice willows

Willow leaf rust (Melampsora epitea) is an important leaf pathogen in short rotation coppice plantations. Although ecological factors influencing rust severity are rather well known, to date, the connections between leaf morphological traits and rust infections are poorly studied. The aim of this study was to examine the relation between rust severity and specific leaf area (SLA). Willow leaves of three different clones from waste-water-irrigated and non-irrigated plantation areas were used. The results revealed a significant positive correlation between SLA and rust severity. There were clone specific differences whereas more rust pustules were always accompanied with higher SLA. Waste-water-irrigated plants had higher SLA and always more rust damages. These results suggest that leaves with low SLA are less susceptible to leaf rust in various conditions.     

First report of rust disease on ohia and the causal fungus, <Emphasis Type="Italic">Puccinia psidii</Emphasis>, in Japan

In 2007, a rust disease of ohia (Metrosideros polymorpha) was found in Japan. We identified this pathogen as Puccinia psidii based on its morphological characters and the internal transcribed spacer (ITS) sequence of the ribosomal DNA. This pathogen was pathogenic on Eucalyptus amplifolia and E. rudis in addition to previously reported host species. This is the first report in Japan of a rust disease on ohia and the occurrence of its causal fungus, P. psidii.     

多堆柄锈菌侵染玉米的细胞学及超微结构特征

为明确玉米对多堆柄锈菌Puccinia polysora侵染后病理反应的细胞学特征,利用扫描和透射电镜技术分析了玉米自交系与多堆柄锈菌互作中二者的细胞变化过程。多堆柄锈菌对玉米的侵染主要以直接穿透叶片表皮侵入为主,少量可从气孔和细胞间隙侵入。接种后,病菌夏孢子在感病自交系叶片上快速并大量萌发,在叶表生长蔓延并侵入表皮组织细胞,7 d后形成夏孢子堆;在抗病自交系上,病菌萌发、菌丝生长均受到明显抑制,少量入侵的病菌也由于寄主细胞死亡而导致菌丝和夏孢子干瘪死亡。侵染早期在感病寄主细胞间隙出现菌丝并穿透细胞壁,在胞内产生分枝菌丝,此时寄主细胞结构正常;随着菌丝进一步扩展,叶绿体等结构发生紊乱,被侵染细胞逐渐死亡。在抗病自交系上,接菌24 h后寄主即出现过敏性坏死反应,侵入位点与周围细胞快速坏死,抑制菌丝生长蔓延;叶绿体中清晰可见深色颗粒状物质;72 h后细胞壁外侧产生大量致密的深色结晶体,应为与抗病反应相关的酚类物质。表明抗多堆柄锈菌的玉米材料可能存在2种抗病途径,即寄主与病菌互作中由分子识别引起的免疫反应和病菌侵入后的系统防卫反应。     

Plantainlily rust fungus is distinct from daylily rust fungus

Plantainlily rust fungus, Puccinia funkiae, was proven to host-alternate between Hosta species (plantainlilies) and a patrinia, Patrinia villosa. Unlike Puccinia hemerocallidis (daylily rust fungus), P. funkiae was not pathogenic on Patrinia scabiosaefolia or on Hemerocallis species (daylilies). The urediniospores were also larger and thicker-walled than those of the daylily rust fungus. The two or three urediniospore germ pores of the plantainlily rust fungus were equatorially distributed, whereas there were several germ pores in P. hemerocallidis spores, and they were scattered over the wall. Thus, P. funkiae is biologically and taxonomically distinct from P. hemerocallidis.     

Genetic Structure of Melampsora Epitea Populations in Swedish Salix Viminalis Plantations

Amplified fragment length polymorphism (AFLP) was used to study the genetic structure of populations of the willow leaf rust, Melampsora epitea, in Swedish willow plantations. In total, 197 isolates collected from Salix viminalis clones in three locations in Sweden were analysed. AFLP profiles based on 83 markers were used to compute genetic distances between pairs of individuals. High levels of gene and genotypic diversity were detected in all populations, with 96% of the AFLP loci being polymorphic and with normalized Shannon's diversity indices ranging from 0.977 to 1.0. Analysis of molecular variance (AMOVA) showed small significant differences among locations, although most of the molecular variability was found within locations (97.5%). Five isolates from one willow clone in one location differed markedly from the common pattern. When these five exceptional isolates were excluded, no significant differences among willow clones were found with AMOVA. Sexual reproduction and spore migration appear to be important factors for the population genetic structure of this pathogen.     

Melampsora larici-populina, the main rust pathogen, causes loss in biomass production of black cottonwood plantations in the south of China

Epidemic outbreaks of rust disease have been observed in most of the black cottonwood (Populus trichocarpa) plantations in the south of China in recent years. However, the exact pathogens that cause rust disease in this area remain largely unknown. In this study we collected rust fungi from black cottonwood plantations at four different places in the south of China. Examination of these fungi by scanning electron microscope (SEM) and light microscopy (LM) revealed that the morphological characteristics of urediniospores for all the collected fungi were very close to that of Melampsora larici-populina. Using species-specific primers, these pathogens were confirmed to be M. larici-populina. In a survey on the resistance to rust disease for 88 genotypes of black cottonwood, nine potential candidate genotypes were detected that may be free from infection of rust pathogen. The results of this study provide essential information for breeding new rust-resistant black cottonwood cultivars.     

Rhamnus lycioides in Tunisia is a new aecial host of oat crown rust

Puccinia coronata was not previously described on Rhamnus spp. in Tunisia. Three sites in the northwest of Tunisia, where Rhamnus is reported to be abundant, were surveyed for the presence of pycnia and aecia of oat crown rust caused by Puccinia coronata f. sp. avenae. Two Rhamnus species (R. lycioides and R. alaternus) were encountered in the sites. Pycnia with viable pycniospores and aecia with viable aeciospores were found on R. lycioides. However, no characteristic structures of crown rust were found on R. alaternus. Aeciospores collected from leaves of R. lycioides were used to inoculate oat plants usually susceptible to oat crown rust. Typical uredinia containing oat crown rust urediniospores appeared on the leaves of these plants. Moreover, the sixteen Pc-gene differential oat lines, used by oat researchers to study the virulence pattern in oat crown rust populations, were artificially inoculated with aeciospores from R. lycioides. These inoculated lines showed resistance/susceptibility similar to the registered resistance level of these lines to crown rust under field conditions in Tunisia. These results indicate that R. lycioides, a common and endemic part of the vegetation in the northwest of Tunisia, is a new aecial host of oat crown rust. The aeciospores produced on this forest plant could constitute the source of the virulence diversity already detected via the Pc-gene line trials.