中国链格孢属的分类研究IV.生于夹竹桃科和番木瓜科植物上的新种和新变种

报道生于夹竹桃科(Apocynaceae)植物上的链格孢新种2个、新变种2个,即络石链格孢(Alternaria trachelospermi T. Y. Zhang,X. F. Lin et W．Q．Chen)、细极链格孢络石生变种[A.Tenuissima (Nees ex Fr.) Wiltshire var．Trachelospermicola T. Y. Zhang,X. F. Lin et W. Q.Chen]、细极链格孢长春花变种[A. tenuissima (Nees ex Fr．) Wiltshim var catharanthi T. Y. Zhanget X. F. Lin]和长春花生链格孢(A. catharanthicola T．Y Zhang),及生于番木瓜科(Caricaccae)植物上的番术瓜链格孢(A. caricae T. Y. Zhang,W．Q Chen et X. F. Lin)。新种和新变种均有拉丁文特征描述,并附绘图。新分类单位的模式标本分别存放在西北农业大学真菌标本室(HMUABO)和山东农业大学植物病理标本室(HSAUP)．     

中国链格孢属的分类研究 Ⅳ.生于夹竹桃科和番木瓜科植物上的新种和新变种(英文)

报道生于夹竹桃科（Ａｐｏｃｙｎａｃｅａｅ）植物上的链格孢新种２个、新变种２个,即络石链格孢（Ａｌｔｅｒｎａｒｉａ　ｔｒａｃｈｅｌｏｓｐｅｒｍｉ　Ｔ．Ｙ　Ｚｈａｎｇ,Ｘ,Ｆ,Ｌｉｎ　ｅｔ　Ｗ．Ｑ．Ｃｈｅｎ）、细极链格孢络石生变种［Ａ．ｔｅｎｕｉｓｓｉｍａ（Ｎｅｅｓｅｘ　Ｆｒ．）Ｗｉｌｔｓｈｉｒｅｖａｒ．ｔｒａｃｈｅｌｏｓｐｅｒｍｉｃｏｌａ　Ｔ．Ｙ．Ｚｈａｎｇ,Ｘ．Ｆ．ＬｉｎｅｔＷ．Ｑ．Ｃｈｅｎ］、细极链格孢长春花变种［Ａ．ｔｅｎｕｉｓｓｉｍａ（ＮｅｅｓｅｘＦｒ．）Ｗｉｌｔｓｈｉｒｅｖａｒ．ｃａｔｈａｒａｎｔｈｉＴ,Ｙ．ＺｈａｎｇｅｔＸ．Ｆ．Ｌｉｎ］和长春花生链格孢（Ａ.ｃａｔｈａｒａｎｔｈｉｃｏｌａＴ．Ｙ．Ｚｈａｎｇ）,及生于番木瓜科（Ｃａｒｉｃａｃｅａｅ）植物上的番木瓜链格孢（Ａ．ｃａｒｉｃａｅ　Ｔ．Ｙ．Ｚｈａｎｇ,Ｗ．Ｑ．Ｃｈｅｎ　ｅｔ　Ｘ．Ｆ．Ｌｉｎ）．新种和新变种均有拉丁文特征描述,并附绘图．新分类单位的模式标本分别存放在西北农业大学真菌标本室（ＨＭＵＡＢＯ）和山东农业大学植物病理标本室（ＨＳＡＵＰ）．     

河北省冬枣黑斑病病原菌的分离鉴定及生物防治初探

冬枣黑斑病是冬枣重要病害之一,目前多以化学农药进行防治,给自然环境和人类健康带来了严重的威胁。河北省是冬枣种植大省,进行冬枣黑斑病病原菌的分离鉴定对冬枣黑斑病的有效防治具有重要意义。2014年8月至10月从河北省沧州、衡水、邯郸、邢台等地采集冬枣黑斑病病果,采用PDA培养基进行病原菌分离,从病样中共分离出2株分离频率较高的真菌,经过回接和再分离实验筛选出河北省冬枣黑斑病的致病菌株,经形态学和ITS序列分析初步确定该菌为细交链格孢(Alternaria alternata)。以枯草芽胞杆菌J18进行冬枣采后黑斑病的防治,浓度为1×108cfu/m L的菌液对病害的防效为80.67%。     

枣缩果病拮抗菌的鉴定及其拮抗效应

【目的】发掘有效生防菌株以控制枣缩果病,并探究生防菌株的拮抗特性。【方法】采用梯度稀释法和平板对峙法筛选出2株对枣缩果病菌细极链格孢(Alternaria tenuissima)具有显著拮抗作用的菌株STO-12和STO-45,通过PCR扩增得到其16S rRNA基因序列,进行同源比对分析和分子系统树的构建,并结合形态学观察和生理生化实验对菌株进行鉴定。采用皿内对峙、显微观察及蛋白质抑菌试验等测定了菌株STO-45的拮抗效应。【结果】两拮抗菌株STO-12和STO-45均鉴定为枯草芽孢杆菌,但菌株STO-12能产生橘红色色素,且两菌株在大小、生理生化特征及系统发育关系上具有生理差异。这两株拮抗细菌的发酵液、发酵上清液及发酵滤液均对枣缩果病菌具有显著抑菌活性。STO-45发酵滤液在0.8%的低体积浓度下即达到抑制中浓度,可使病原菌A. tenuissima MY5的菌丝及芽管部分畸形膨大,发酵液中的蛋白类物质可能是其拮抗物质之一。【结论】拮抗菌株STO-12和STO-45对枣缩果病的生物防治均具有潜在的应用价值,其抑菌机制及生物制剂的开发利用值得进一步研究。     

细极链格孢菌peaT2基因在毕赤酵母中的表达及蛋白功能确定

从细极链格孢菌表达文库获得阳性克隆子,序列分析表明,克隆的DNA片段中含有完整的开放阅读框架,将该基因命名为peaT2(GenBank登录号为EF212880)。用PCR法扩增peaT2基因的编码序列并亚克隆到毕赤酵母表达系统的表达载体pPIC9K上,得到重组质粒pPIC9K/peaT2。重组质粒经SacⅠ线性化后用电穿孔法导入到毕赤酵母(Pichia pastoris)GS115中,采用MD、G418-YPD平板和PCR法筛选Mut 表型,获得了分泌表达的重组毕赤酵母。随机挑取一菌株作为表达菌,用甲醇诱导PeaT2蛋白表达。SDS-PAGE及Western blot检测结果均表明PeaT2在毕赤酵母中成功地分泌表达。用peaT2基因的表达蛋白处理小麦种子,生物测定表明,表达蛋白能明显促进小麦的生长,具有蛋白激发子作用。     

枫香叶斑病病原菌

从福建多地采集了55份感染叶斑病的枫香植物病样,包含叶片、叶柄、枝条和树皮。通过分离纯化得到了12个类拟盘多毛孢属真菌菌株,综合形态特征以及3个基因(ITS、β-tubulin和tef1)的分子系统发育分析结果,分别鉴定为Neopestalotiopsis cocoes、N. chrysea、Pestalotiopsis neglecta和P. neolitseae,均为枫香上首次报道,其中N. cocoes在国内首次被发现。通过柯赫氏法则验证,发现N. cocoes能够侵染叶片、叶柄和枝条,N. chrysea能侵染叶片和枝条,P. neglecta能侵染叶柄和枝条,而P. neolitseae不能侵染枫香植物组织。     

一串红叶斑病的病原菌鉴定

一串红Salvia splendens叶斑病被发现在杭州市农科所栽培花卉的遮阳网大棚中,是由棒孢霉属真菌侵染引起的。在田间,病原菌侵染植株的茎和叶片,引起当年移植苗发生茎腐、落叶、植株枯萎和死亡。通过对病原菌形态学观察以及核糖体DNA ITS序列分析,证明侵染一串红的病原菌为决明生棒孢霉菌Corynespora cassiicola。致病性试验结果表明,一串红是决明生棒孢霉菌的寄主。种子带菌检验结果显示,种子带菌率仅为1%。     

中国链格孢属的研究I．

本文报道链格孢属的2个新种：寄生在苦术科(Simaroubaceae)臭椿[Ailanthus altissima(Mill)Swingle]上的臭椿链格孢(Alternaria ailanthi sp nov),寄生在桦术科(Betulaceae)黑桦(Betuladahurica Pall)上的桦术链格孢(A. betulae sp nov.),2个新组合：豆链格孢[A．Azulaae (Hara)comb．Nov],蔷薇生链格孢[A. rosicola(Rao) comb. Nov]和1个新名称红花链格孢(A．Carthami-tinctoriinom nov．)。文中为新种提供了拉丁文简介、描述和图。模式标本保藏在山东农业大学植物病理标本室(HSAUP)．     

中国链格孢属的研究I.(英)

本文报道链格孢属的2个新种：寄生在苦木科（Simaroubaceae）臭椿［Ailanthusaltissima（Mill.）Swingle]上的臭椿链格孢（Alternariaailanthispnov）,寄生在桦木科（Betulaceas）黑桦（BetuladahuricaPall.）上的桦木链格孢（A．betalaesp．nov．）,2个新组合：豆链格孢［A．azukiae(Hara)comb.nov.],蔷薇生链格孢[A.rosicola（Rao）comb.nov.]和1个新名称红花链格孢（A．carthami-tinctoriinom．nov）。文中为新种提供了拉丁文简介、描述和图。模式标本保藏在山东农业大学植物病理标本室（HSAUP）。     

三七锈斑病的病原菌

锈腐病是三七根腐病中发病率最高的一种,其病原是柱孢属真菌Cylindrocarpon sp.。作者认为柱孢属真菌侵染三七根部后引起的症状不一,可引起黑腐、锈裂和锈斑3类不同的症状,本文报道的是引起三七块根锈斑症状的病原菌,对采自云南省文山州砚山县的发病植株进行了症状观察,并进行病原菌的分离培养和显微形态特征观察、致病性测定及r DNA-ITS序列分析,确定该类型的病害是由毁灭柱孢粗孢变种Cylindrocarpon destructans var.crassum侵染引起。     

Two cases of cutaneous phaeohyphomycosis by Alternaria alternata and Alternaria tenuissima

Two cases of cutaneous phaeohyphomycosis, one with a nodular appearance and the other with an erythematous infiltrating patch, are reported in immunocompromised patients. Diagnosis was based on histological examination, which revealed hyphae and round-shaped fungal cells in a granulomatous dermal infiltrate, and on identification of the moulds when biopsy fragments were cultured on Sabouraud-dextrose agar without cycloheximide. The pathogens were Alternaria tenuissima in the first case and A. alternata in the second. The fungi were examined by scanning electron microscopy. The patients were checked for bone and lung involvement and were then treated with surgical excision and itraconazole, and itraconazole only, respectively, with clinical and mycological resolution. This revised version was published online in August 2006 with corrections to the Cover Date.     

Morphology,phylogeny and pathogenicity of Alternaria species,involved in leaf spot disease of sunflower in northern Iran

Leaf spot disease of sunflower is one of the most important foliar diseases on this crop worldwide. Several fungal groups are known to cause leaf spot disease on sunflower. Species of the genus Alternaria are the most common and serious leaf spot causing fungi on this crop. Leaf spot disease is the most destructive foliar diseases on sunflower in northern Iran; however, the identity of the causal agent remains unknown. The present study was aimed to characterise the identity of the causal agent of the disease by means of morphological and molecular data as well as to evaluate the pathogenicity of the responsible species. For this purpose, a total number of 97 fungal isolates were recovered from sunflower leaves with leaf spot disease symptoms from the sunflower fields in northwestern zone of Iran. All of the isolates were identified as Alternaria alternata based on cultural and morphological characteristics. A subset of isolates was subjected to phylogenetic analysis using sequence data from ITS-rDNA region, gpd and rpb2 genes. Sequence data from ITS-rDNA and gpd did not discriminate A. alternata from the other small-spored Alternaria species. A phylogeny inferred using sequence data from rpb2 gene clustered our isolates in several sub-clades within a single monophyletic clade. Sequence data for the type strain of the other small-spored Alternaria species has to be included in phylogenetic analysis, in order to make sure, whether the observed variations in rpb2 gene sequences are an indication for the population variation in sunflower isolates of A. alternata or define species boundaries among the small-spored Alternaria species. The results of pathogenicity assay on sunflower plants (cultivar Euroflor) under greenhouse condition revealed that A. alternata is pathogenic on sunflower.     

Establishment of seed-borne nature of Alternaria alternata causing leaf spot and fruit rot of chilli

Study on seed-borne nature of Alternaria alternata in chilli seeds indicated that in Standard blotter method, the incidence of A. alternata was 5.7–15.3% (average, 9.5%) and 16.5–28.4% (average, 21.7%) with unsterilsied seeds collected from general fields and diseased fields, respectively. The incidence for surface sterilised seeds from general and diseased fields was 2.6–7.2% (average, 4.9%) and 7.8–13.0% (average, 9.6%), respectively. In agar plate method with potato dextrose agar medium, the incidence of A. alternata was 4.0–10.5% (average, 7.4%) and 11.0–24.0% (average, 18%) with surface sterilised.     

Post‐infectional dynamics of leaf spot disease in Withania somnifera

Withania somnifera is a high value medicinal plant, native to Indian sub‐continent, and is extensively used in traditional systems of medicine. It is highly prone to leaf spot disease caused by Alternaria alternata, that may affect the quality of crude herbal drugs. In the present study, the accumulation of ROS (reactive oxygen species) was detected histochemically within the infected host tissue, using H₂DCFDA (2′,7′‐difluorodihydrofluorescein diacetate) and DAB (3,3′‐diaminobenzidine) staining methods. This ROS accumulation was linked with the process of disease initiation. The microscopy studies were conducted to explore the site of pathogen invasion into the host tissue. Some changes related to tissue degeneration during the infection process have also been reported. The observed changes in the form of reducing sugar and phenolic content showed an enhancement during infestation. Carbon, nitrogen and sulphur exhibited a decreasing trend with the progression of disease. Both the net rate of photosynthesis (A) and stomatal conductance (g_S) showed a similar trend except that g_S increased at the early stage of infection when the protruding fungal hyphae obstructed the stomatal closure. Further, the disintegration of chloroplasts was also observed in the infected leaves. Overall, the present study highlights a few potential targets for enhancing the disease resistance against the leaf spot pathogen of W. somnifera.     

稗草叶枯病病原尖角突脐孢菌的鉴定

Three fungal isolates, KF-1, HN-14 and K-12, from barnyardgrass leaf blight, which were collected from Hunan and Beijing, were studied morphologically and molecularly. The results showed that there were differences between the three isolates and the two Exserohilum monoceras strains G-9 and X-27 which were accurately identified and deposited in culture collections of China Agricultural University in colonial morphology, sporulation and spore morphology especially septa of spore. G-9, KF-1, X-27 and HN-14 grow quickly and produce abundant spores on PDA plate, but K-12 grows slowly and produced less spores. To further identify the relationship of 5 isolates, 5.8S-ITS sequence were compared. Results indicated that the similarity of ITS sequence of five isolates were over 98% and the phylogenetic tree based on ITS1 and ITS2 sequence also revealed that G-9, KF-1, K-12, X-27, and HN-14 were all clustered into one group and distinct from the other outgroup and suboutgroup. Based on the above data, these three isolates were proved to be E. monoceras.     

稗草叶枯病病原尖角突脐孢菌的鉴定

采用形态学及分子生物学的方法对采集自湖南和北京的3株尖角突脐孢菌分离物进行了鉴定。结果表明,3株分离物(KF-1、HN-14和K-12)和保存于中国农业大学已定名的尖角突脐孢菌菌株G-9和X-27之间在菌落形态、产孢量及孢子大小和分隔方面存在较大差异。其中,K-12在PDA培养基上生长缓慢、产孢量小;菌株G-9、KF-1、X-27和HN-14生长迅速,产孢丰富。对菌株进行分子鉴定结果表明,菌株间ITS区序列相似度达98%以上,聚类分析也表明,种内各菌株之间的遗传距离明显小于种间的遗传距离;基于ITS1及ITS2序列,能将尖角突脐孢菌和突脐蠕孢属中其它种分开。由此可确定分离自湖南水稻田及中国农业大学科学园温室中自然发病的稗草病样上的3株病原真菌均为尖角突脐孢菌。     

Phylogenetic and enzymatic variability of Alternaria species isolated from various substrates in Qena governorate of Upper Egypt

Recently, 24 sections were characterised in the genus of Alternaria. In this work, 27 isolates of Alternaria belonging to section Alternaria were isolated from different sources in Qena governorate, Egypt. The collected strains were identified using multi-locus products of internal transcribed spacer (ITS) region, small subunit (SSU), large subunit (LSU) and Alt a1 gene. Based on four loci, the phylogenetic analysis revealed that 26 isolates (96.3% of total isolates) identified as A. alternata and the last one isolate (3.7%) as A. arborescens. The different strains of Alternaria exhibited enzymatic variability ranged from 0.1 ± 0.07–2.3 ± 0.13U/ml for cellulase and 0.6 ± 0.20–3.7 ± 0.47 U/ml (pectinase). Within A. alternata isolates, biochemical properties (Cellulase and pectinase) did not correlate either to phylogenetic analysis or strain origin.     

Isolation and characterization of polymorphic microsatellite markers for Alternaria alternata

Alternaria alternata is of major significance as a food and feed contaminant and is able to produce a range of mycotoxins that may elicit adverse effects in both animals and humans. We describe the isolation and characterization of five microsatellite markers for studying A. alternata. Marker polymorphism was screened in 64 isolates of A. alternata. The number of alleles per locus ranged from eight to 24, and allelic diversity ranged from 0.425 to 0.882. These markers will be useful in the study of relationships and population genetics amongst isolates of A. alternata.     

昆明美人蕉黑斑病菌——链格孢Alternaria alternata

美人蕉是重要的园林绿化植物和生物资源。为了明确美人蕉黑斑病的病原菌种类,并为病害防治提供理论指导,调查了昆明市美人蕉黑斑病的发生情况,采用组织分离法对病原物进行了分离和纯化,并进行了致病性测定。通过形态学和rDNA ITS序列分析,将昆明美人蕉黑斑病的病原菌鉴定为链格孢Alternaria alternata。