Host Range and Virulence of a Fungal Pathogen for Control of Giant Salvinia (<i>Salvinia molesta</i>)

A teleomorph of the fungus Botryosphaeria rhodina (Berkeley et Curtis) von Arx, (Br) was evaluated as a bioherbicide for control of giant salvinia (Salvinia molesta D.S. Mitchell) under greenhouse conditions and in small-scale field trials. We found that fungal mycelium was highly infective and could be rapidly produced (48+ h) in soy flour-cornmeal liquid media contained in shake flasks or fermenters. A dew period was not required to achieve infection and mortality of inoculated plants. A surfactant (Silwet L-77, a polyalkyleneoxide modified heptamethyl-trisiloxane) incorporated in the fungal formulation was required for Br to infect and kill plants. Infection and mortality occurred rapidly (within 48 h after treatment), and re-growth of treated plants did not occur. In replicated field trials, Br controlled giant salvinia ~95%. Br also infected other plants, such as common salvinia (S. minima Baker), and Azolla filiculoides Lam., as determined in ongoing host range research. However, no symptomatology was observed on several economically important crop species, such as rice (Oryza sativa L.), corn (Zea mays L.), and several woody species such as bald cypress (Taxodium distichum L.) and loblolly pine (Pinus taeda L.) occurring in areas where giant salvina occurs that would be subject to contact with releases of Br. These results suggest that this teleomorph of Botryosphaeria rhodina has potential as a bioherbicide for controlling this onerous aquatic weed.

多主棒孢菌致真菌性角膜溃疡1例并文献复习

目的报道1例多主棒孢菌引起的真菌性角膜溃疡病例并复习相关文献,提高临床对该菌引起感染性疾病的认识。方法回顾性分析1例多主棒孢菌致真菌性角膜溃疡病例资料,并以英文关键词“Corynespora cassiicola”、中文关键词“棒孢菌”和“棒孢霉”为检索词,检索PubMed、中国知网、万方和维普数据库等国内外报道的病例,结合文献综合分析多主棒孢菌临床感染的特点。结果该例患者临床表现和实验室检查符合真菌性角膜溃疡的临床特征,病变角膜组织培养提示多主棒孢菌生长,经右眼角膜移植术及抗真菌治疗后好转。复习文献并结合该例,共12例多主棒孢菌临床感染病例。除1例病例资料不完整外,其余11例中男8例,女3例,年龄8~84岁。患者多存在基础疾病,包括糖尿病2例、慢性阻塞性肺疾病1例、高血压1例、慢性阻塞性肺疾病合并高血压1例;感染危险因素包括胱天蛋白酶募集域蛋白9(CARD9)基因突变3例、植物暴露4例(3例农民、1例眼外伤)、长期使用激素2例、侵袭性诊疗操作1例;11例均引起暗色丝孢霉病,感染部位包括皮下感染7例、眼部感染3例、中枢神经系统感染1例,临床表现主要与受累组织系统相关;临床治疗中两性霉素B、伏立康唑、伊曲康唑、特比萘芬是最常用的抗菌药物,联合外科手术治疗者3例;临床转归中9例患者好转,2例患者无明显改善。结论多主棒孢菌引起的临床感染罕见,以皮下暗色丝孢霉病为主,眼部感染次之。对于存在基础疾病或免疫功能缺陷,并有植物暴露史的患者,临床应提高警惕。临床以抗真菌治疗为主,外科手术可作为快速清除病原体的重要治疗手段。该菌感染总体预后良好。

拮抗菌株SY-15的鉴定及其抑菌活性分析

拮抗菌株SY-15是从杨树根际土壤中分离获得的一株能高效拮抗金黄壳囊孢菌Cytospora.chrysosperma的拮抗细菌。研究基于形态学特征、生理生化特性和16S rDNA序列分析鉴定了菌株SY-15的分类地位,并分别采用带药平板法和二分皿法分析了其抑菌活性,为进一步开发利用拮抗菌株SY-15提供科学依据。结果表明:拮抗菌株SY-15最终鉴定为枯草芽孢杆菌Bacillus subtilis,其无菌培养滤液和挥发性气体均能有效抑制金黄壳囊孢菌、迂回壳囊孢菌C. ambiens和黑腐皮壳菌C. mali的生长,处理60 h后,无菌培养滤液对3种植物病原真菌的抑菌率分别达到88.89%、60.39%和53.02%。处理36 h后,挥发性气体对3种植物病原真菌的抑菌率分别达到100%、76.98%和63.41%。此外,还发现拮抗菌株SY-15能产生蛋白酶和纤维素酶。研究表明拮抗菌株SY-15是一株潜在的高效防治杨树腐烂病及其他植物真菌病害的菌株资源。

致病性尖孢镰刀菌毒力因子的研究进展

致病性尖孢镰刀菌(Fusarium oxysporum)侵染植物引发的植物枯萎病是世界范围内广泛存在的毁灭性土传真菌病害,目前该菌已被列为世界上第五大植物病原真菌。由于病原菌通过土壤传播,其致病机理尚未完全明确,而充分了解尖孢镰刀菌的致病机制是对抗这种疾病的先决条件。为了更好的研究和实施有效控制策略从而限制宿主植物感染,本文归纳了尖孢镰刀菌的致病机理,总结了毒力因子中的细胞壁降解酶、毒素、信号传导途径(MAPK通路)对致病进程的影响,分析了毒力基因及转录因子在感染过程中的调控机理。以期能为防控尖孢镰刀菌引起的枯萎病提供作用靶点和理论依据。

AFLP技术在植物病原真菌种群遗传上的应用

介绍了植物病原真菌种群遗传的概念及其研究的必要性 ,并综述了新一代分子标记技术─AFLP在该领域的应用 ,以期对病害研究推荐更有效的新方法。

Assessing global fungal threats to humans

Fungi are an integral part of the earth's biosphere.They are broadly distributed in all continents and ecosystems and play a diversity of roles.Here,I review our current understanding of fungal threats to humans and describe the major factors that contribute to various threats.Among the 140,000 or so known species out of the estimated six million fungal species on Earth,about 10%directly or indirectly threaten human health and welfare.Major threats include mushroom poisoning,fungal allergies,infections of crop plants,food contamination by mycotoxins,and mycoses in humans.A growing number of factors have been identified to impact various fungal threats,including human demographics,crop distributions,anthropogenic activities,pathogen dispersals,global climate change,and/or the applications of antifungal drugs and agricultural fungicides.However,while models have been developed for analyzing various processes of individual threats and threat managements,current data are primarily descriptive and incomplete,and there are significant obstacles to integration of the diverse factors into accurate quantitative assessments of fungal threats.With increasing technological advances and concerted efforts to track the spatial and temporal data on climate and environmental variables;mycotoxins in the feed and food supply chains;fungal population dynamics in crop fields,human and animal populations,and the environment;human population demographics;and the prevalence and severities of fungal allergies and diseases,our ability to accurately assess fungal threats will improve.Such improvements should help us develop holistic strategies to manage fungal threats in the future.