蓝莓拟盘多毛孢枝枯病的病原菌

近期在山东省蓝莓种植区发现1种枝枯病害。为明确该致病菌,通过病原菌组织分离和接种试验获得2个致病菌株。通过形态学观察和rDNA‐ITS序列分析,确定该病原菌为棒状拟盘多毛孢Pestalotiopsis clavispora。这是棒状拟盘多毛孢所致蓝莓枝枯病在国内的首次报道。     

福建省木本植物上的拟茎点霉新种

报道了采自福建省木本植物枝上的6个拟茎点霉 Phomopsis 新种: 阳桃拟茎点霉 Ph. averrhoae、胡颓子生拟茎点霉 Ph. elaeagnicola、光叶子花拟茎点霉 Ph. glabrae、枫香拟茎点霉 Ph. liquidambaris、含笑拟茎点霉 Ph. micheliae 和叶下珠生拟茎点霉Ph. phyllanthicola。对新种与近似种在形态上的差异进行了讨论。新种附有拉丁文描述及显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

香山黄栌枯萎病叶片真菌的分离与鉴定

利用微生物培养方法及多相分类鉴定技术,对分离自香山黄栌枯萎病叶片样品的真菌菌株进行分离与鉴定,共分离到丝状真菌22株,分属细极链格孢(Alternaria tenuissima)、草酸青霉(Penicillium oxalicum)、腊梅拟茎点霉(Phomopsis chimonanthi)和葡萄茎枯病菌(Phoma glomerata)4个菌种,并保藏于中国工业微生物菌种保藏管理中心(CICC)。其中细极链格孢(11株)和腊梅拟茎点霉(7株)为优势菌种。细极链格孢、腊梅拟茎点霉、葡萄茎枯病菌均为已报道的植物病原菌,可能为香山黄栌枯萎病潜在病原菌。     

湖南省木本植物上的拟茎点霉新种

报道了采自湖南省木本植物上的10个拟茎点霉Phomopsis新种,即喜树拟茎点霉Ph. camptothecae、腊梅拟茎点霉Ph.chimonanthi、杜仲生拟茎点霉Ph.eucommiicola、紫薇拟茎点霉Ph.lagerstroemiae、红继木拟茎点霉Ph.loropetali、厚朴拟茎点霉Ph.magnolina、海桐拟茎点霉Ph.pittospori、竹柏拟茎点霉Phomopsis podocarpi、石榴拟茎点霉Ph.punicicola和酸枣拟茎点霉Ph.ziziphicola。对新种与其近似种在形态及ITS序列上的差异进行了讨论。文中附有新种的拉丁文、英文描述及显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

蓝莓毛色二胞枝枯病的病原菌

近期在山东胶南的蓝莓种植区发现一种枝枯新病害,被侵染的枝条变色坏死,甚至引起全株干枯死亡。通过组织分离法和玻璃毛细管法获得纯化菌株HMQAU140073。通过形态学观察、rDNA-ITS和EF1-α序列分析及柯赫氏法则验证,确定该病原菌为假可可毛色二胞Lasiodiplodia pseudotheobromae。这是假可可毛色二胞所致蓝莓枝枯病的首次发现。     

采自广州的六个拟茎点霉新种

报告了采自广州的六个拟茎点霉Phomopsis新种:金合欢生拟茎点霉Phomopsis acacicola、叶子花生拟茎点霉Phomopsis bougainvilleicola、樟生拟茎点霉Phomopsis cinnamomicola、八宝树拟茎点霉Phomopsis duabangae、杜鹃拟茎点霉Phomopsis rhododendri和黄花夹竹桃拟茎点霉Phomopsis thevetiae。新种附有拉丁文、英文描述和显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

采自西双版纳的三个拟茎点霉新种

报道了采自云南西双版纳的三个拟茎点霉Phomopsis新种:猴面包树拟茎点霉Ph. adansoniae、橡胶生拟茎点霉Ph. heveicola和蒲桃生拟茎点霉Ph. syzygiicola。猴面包树拟茎点霉分生孢子梗较长且宽,甲型分生孢子纺锤形,不同于木棉科植物上已报道的拟茎点霉种。橡胶生拟茎点霉与橡胶拟茎点霉Ph. heveae的主要区别在于前者分生孢子梗较宽,甲型和乙型分生孢子较窄。蒲桃生拟茎点霉与蒲桃拟茎点霉Ph. syzygii的主要区别是前者分生孢子梗合轴分枝,甲型分生孢子具2个油球。新种附有拉丁文、英文描述及显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

采自广州的六个拟茎点霉新种

报告了采自广州的六个拟茎点霉Phomopsis新种：金合欢生拟茎点霉Phomopsis acacicola、叶子花生拟茎点霉Phomopsis bougainvilleicola、樟生拟茎点霉Phomopsis cinnamomicola、八宝树拟茎点霉Phomopsis duabangae、杜鹃拟茎点霉Phomopsis rhododendri和黄花夹竹桃拟茎点霉Phomopsis thevetiae。新种附有拉丁文、英文描述和显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

苏木科植物上的拟茎点霉新种及中国新纪录种

报道了苏木科植物上的两个拟茎点霉 Phomopsis 新种：羊蹄甲生拟茎点霉 Phomopsis bauhinicola 和决明生拟茎点霉 Phomopsis cassiicola ，和两个中国新记录种：羊蹄甲拟茎点霉 Phomopsis bauhiniae 和决明拟茎点霉 Phomopsis cassiae 。新种附有拉丁文、英文描述和显微结构图。模式标本保存于华南农业大学真菌标本室(HMA)。     

广东省草本花卉上的拟茎点霉新种和新记录种

报道了采自草本花卉上的一个拟茎点霉Phomopsis新种(千日红拟茎点霉Ph.gomphrenae)和两个中国新记录种(风仙花拟茎点霉Ph.impatientis与埋生拟茎点霉Ph.immersa)。新种千日红拟茎点霉的甲乙型分生孢子不论长度还是宽度均小于之前报道的两个拟茎点霉,并且缺少第三种分生孢子。新种附有拉丁文描述及显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

Morphological and molecular characterization of Phomopsis vaccinii and additional isolates of Phomopsis from blueberry and cranberry in the eastern United States

Forty isolates of Phomopsis were obtained from twigs and berries of highbush blueberry, Vaccinium corymbosum, and cranberry, Vaccinium macrocarpon, isolated primarily from plants grown in the eastern United States. They were characterized using conidiomatal morphology, conidial dimensions, colony appearance and growth rate, and sequences of ITS rDNA. Based on morphological and molecular similarities, most isolates grouped together with an authentic culture of Phomopsis vaccinii Shear. This taxon is described and illustrated. However, some Phomopsis isolates from Vaccinium differed in colony and conidiomatal morphology from P. vaccinii and, based on ITS sequences, were related to isolates of Phomopsis from diverse hosts. These isolates were excluded from P. vaccinii.     

<Emphasis Type="Italic">Synnemapestaloides rhododendri</Emphasis>, a new genus and new species of synnematous hyphomycete,causing synnemapestaloides twig blight disease of <Emphasis Type="Italic">Rhododendron brachycarpum</Emphasis> in Japan

A hyphomycete with black synnema and appendaged phragmoconidia was collected on Rhododendron brachycarpum showing twig blight symptom in Aomori Prefecture, Japan. The twig blight is macroscopically similar to the disease symptoms caused by Pycnostysanus azaleae. The fungus, however, has determinate synnemata, (1–)3-level verticillately branched conidiophores, and Pestalotia-like conidia. It cannot be accommodated by any existing genus of anamorphic fungi. A new genus Synnemapestaloides is established to accommodate the fungus, which is named S. rhododendri. The pathogenicity of the fungus on Rhododendron leaves and shoots is confirmed by inoculation. Synnemapestaloides twig blight is proposed for the disease of R. brachycarpum caused by the fungus.     

Nutritional requirements of antagonists to peach twig blight,Monilinia laxa,in relation to biocontrol

Different carbon and nitrogen sources and accessory substances were tested to determine their effect on the growth and sporulation of the peach twig blight pathogen,Monilinia laxa, and of three of its antagonists (Penicillium frequentans, Penicillium purpurogenum andEpicoccum nigrum), since the success in twig blight biological control by treatments with the fungal antagonists depends on the type of nutrients added to the antagonist formulation. Combinations of sucrose-ammonium tartrate, glucose-(NH₄)₃PO₄-folic acid and lactose-KNO₃ were selected from these laboratory experiments because they enhanced the growth and sporulation ofP. frequentans, P. purpurogenum andE. nigrum, respectively, but notM. laxa. In glasshouse experiments, twig blight was reduced following the application of mixtures of antagonists with the corresponding enhancing nutrients.     

健康与凋萎病杨梅树体及根围菌群的差异

凋萎病是制约杨梅产业发展的严重病害。为了有效防控凋萎病,本研究分析了杨梅健康和感染凋萎病树体各部位及根表土和根围土中细菌和真菌群落的丰富度与多样性的差异。结果表明: 与健康树相比,病树根围土、根表土、根、枝干、枝皮和叶片的细菌和真菌丰富度均发生了显著变化,其中,根表土细菌和枝皮内真菌的丰富度和多样性均显著降低,而枝皮内细菌和根表土的真菌丰富度和多样性均显著升高。病树各部位及根表、根围土细菌和真菌的优势菌相对丰度在门、纲和属水平上发生了明显的变化,在病树枝干、根和根表土中的假单胞菌属及根表土、根围土中的镰刀菌属的相对丰度明显降低,病树根表土及根围土中青霉菌属的相对丰度明显增加。与凋萎病菌同属的拟盘多毛孢菌在病树根内显著减少,而在其他位置均大量增殖,其相对丰度与多数相对丰度较高的真菌呈正相关。本研究结果将为开发杨梅凋萎病的生态改良、培育健康树体和生物防治技术提供有效的理论依据。     

Stromatinia cryptomeriae sp. nov., the teleomorph ofGloeosporidina cryptomeriae causing twig blight of Japanese cedar

A new species,Stromatinia cryptomeriae, is described based on a specimen collected in Iwate Prefecture, Japan. It was found on fallen dead branches and twigs of Japanese cedar,Cryptomeria japonica. The morphology of isolates on potato-dextrose agar (PDA), which were obtained from single ascospores ofS. cryptomeriae, was identical withGloeosporidina cryptomeriae, the causal fungus of Japanese cedar twig blight. In an inoculation test using single ascospore isolates, many minute black spots (sclerotioid bodies; sclerotules) and acervuli ofG. cryptomeriae were formed on the necrotic lesions, which developed into typical symptoms of Japanese cedar twig blight. These results show thatStromatinia cryptomeriae is the teleomorph ofG. cryptomeriae. On PDA, the fungus grew over a range of about 1 to 25°C, with the optimum growth at about 15–20°C.     

Extending chestnut blight hypovirus host range within diaporthales by biolistic delivery of viral cDNA

Biolistic bombardment was used to successfully transform three phytopathogenic fungal species with an infectious cDNA clone of the prototypic hypovirus, CHV1-EP713, a genetic element responsible for the virulence attenuation (hypovirulence) of the chestnut blight fungus, Cryphonectria parasitica. The fungal species included two strains each of C. parasitica and Valsa ceratosperma, as well as one strain of Phomopsis G-type (teleomorph Diaporthe Nitschke); all are members of the order Diaporthales but classified into three different genera. A subset of transformants for each of the fungal species contained CHV1-EP713 dsRNA derived from chromosomally integrated viral cDNA. As has been reported for CHV1-EP713 infection of the natural host C parasitica, biolistic introduction of CHV1-EP713 into the new fungal hosts V ceratosperma and Phomopsis G-type resulted in altered colony morphology and, more importantly, reduced virulence. These results suggest a potential for hypoviruses as biological control agents in plant-infecting fungal pathogens other than the chestnut blight fungus and closely related species. In addition, the particle delivery technique offers a convenient means of transmitting hypoviruses to potential host fungi that provides new avenues for fundamental mycovirus research and may have practical applications for conferring hypovirulence directly on infected plants in the field.     

Comparison of possible phytotoxic metabolites in culture filtrates of the Diaporthe/Phomopsis complex of soybeans

Filter-sterile culture filtrates of isolates of Diaporthe phaseolorum var. caulivora, Diaporthe phaseolorum var. sojae (anamorph Phomopsis sojae), and Phomopsis longicolla, causal agents of stem canker, pod and stem blight, and seed decay, respectively, on soybeans (Glycine max), grown on Czapek-Dox broth inhibited germination of soybean seeds (significant at P=0.05). Wilting and necrosis of excised soybean seedlings was significantly greater than the controls when treated with culture filtrates of P. longicolla and P. sojae. Soybean seedling radicle growth inhibited significantly when culture filtrates of P. longicolla were added.     

Characterization of three-dimensional spatial aggregation and association patterns of brown rot symptoms within intensively mapped sour cherry trees

Background and Aims

Characterization of spatial patterns of plant disease can provide insights into important epidemiological processes such as sources of inoculum, mechanisms of dissemination, and reproductive strategies of the pathogen population. Whilst two-dimensional patterns of disease (among plants within fields) have been studied extensively, there is limited information on three-dimensional patterns within individual plant canopies. Reported here are the detailed mapping of different symptom types of brown rot (caused by Monilinia laxa) in individual sour cherry tree (Prunus cerasus) canopies, and the application of spatial statistics to the resulting data points to determine patterns of symptom aggregation and association.

Methods

A magnetic digitizer was utilized to create detailed three-dimensional maps of three symptom types (blossom blight, shoot blight and twig canker) in eight sour cherry tree canopies during the green fruit stage of development. The resulting point patterns were analysed for aggregation (within a given symptom type) and pairwise association (between symptom types) using a three-dimensional extension of nearest-neighbour analysis.

Key Results

Symptoms of M. laxa infection were generally aggregated within the canopy volume, but there was no consistent pattern for one symptom type to be more or less aggregated than the other. Analysis of spatial association among symptom types indicated that previous year''s twig cankers may play an important role in influencing the spatial pattern of current year''s symptoms. This observation provides quantitative support for the epidemiological role of twig cankers as sources of primary inoculum within the tree.

Conclusions

Presented here is a new approach to quantify spatial patterns of plant disease in complex fruit tree canopies using point pattern analysis. This work provides a framework for quantitative analysis of three-dimensional spatial patterns within the finite tree canopy, applicable to many fields of research.     

Fungal endophytes from Acer ginnala Maxim: isolation, identification and their yield of gallic acid

Aims:  The aim of the study was to isolate the endophytic fungi from Acer ginnala and screen isolates rich in gallic acid.
Methods and Results:  After epiphytic sterilization, 145 fungal endophytes were isolated from the stem, annual twig and seed of Acer ginnala . The endophytes were grouped into ten different taxa, Phomopsis sp., Neurospora sp., Phoma sp., Epicoccum sp., Penicillium sp., Alternaria sp., Fusarium sp., Trichoderma sp., Cladosporium sp. and a species of Pleosporales Incertae Sedis , by their morphological traits and ITS-rDNA sequence analysis. The content and yield of gallic acid of 141 isolates were determined by HPLC. On average, the species of Pleosporales Incertae Sedis had the highest content and yield of gallic acid (13·28 mg g⁻¹ DW; 119·62 mg l⁻¹), while Alternaria sp. had the lowest.
Conclusions:  Of 141 fungal endophytes from A. ginnala , Phomopsis sp. isolate SX10 showed both the highest content and the highest yield of gallic acid (29·25 mg g⁻¹ DW; 200·47 mg l⁻¹).
Significance and Impact of the Study:  Endophytic fungi isolated from A. ginnala may be used as potential producers of gallic acid and other compounds with biological activities, or functioned as elicitors to produce natural compounds.