ABR: Molecular Systematics of Grass Symbionts of the Fungal Family Clavicipitaceae (Hypocreales)

ABR：麦角真菌科（肉座菌目）草共生体的分子系统学

• 批准号: 9707427
• 负责人: Christopher Schardl
• 金额: $ 12.5万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-15 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9707427&HistoricalAwards=false
• 关键词: ABR; Molecular; Systematics; Grass; Symbionts

9707427 Schardl Building upon an impressive record of recent research, Dr. Schardl of the University of Kentucky continues his taxonomic and ecological studies of symbiotic ascomycetous fungi that infect grass plants. These fungal relatives of the infamous 'ergot' fungus live inside various turf grasses and other species, and transmit their spores either asexually through the grass seed ("vertical" infection of the grass's progeny) or following sexual reproduction, through fly-mediated contagion ("horizontal" infection of other grasses in the habitat). The sexually reproducing fungal species have usually been classified in the genus Epichloe, of the Clavicipitaceae family, while the asexual or conidial anamorphs have usually been named in the genus Neotyphodium. Confusion in the taxonomy has, until now, obscured the interesting symbiotic ecology of the fungus and its grass hosts. With DNA sequencing of several targeted nuclear genes, of samples collected over a wide geographical range, and with laboratory and garden tests of mating success between fungal isolates, Dr. Schardl continues to analyze the phylogenetic relationships of Epichloe and Neotyphodium species and suspected relatives. In turn, these genealogically related groups or clades of fungi are correlated with their host grass plants, to determine whether this symbiotic association has closely tracked the history of speciation of the grasses ("co-speciation") or whether new grass hosts are infected, and if so, whether mostly by sexual or by asexual forms of the fungus. New molecular methods of DNA sequencing allow fine-scale analysis of genealogical or phylogenetic relationships among the separately named sexual and asexual forms of fungi, and are being applied by Dr. Schardl in imaginative ways to an ecologically fascinating system of fungal symbionts of turf grasses and related grass species. Whether the fungi "track" the history of speciation of their grass hosts, whether asexual morphs originate from sexual fungal forms or th e opposite, and whether fungal species hybridize to produce some of the currently documented Neotyphodium anamorphs, are just some of the questions being pursued in this renewed award.

小行星9707427 肯塔基州大学的Schardl博士在最近令人印象深刻的研究记录的基础上，继续对感染禾本科植物的共生子囊菌进行分类学和生态学研究。这些真菌亲戚的臭名昭著的'麦角'真菌生活在各种草坪草和其他物种，并通过无性繁殖（“垂直”感染草的后代）或有性繁殖，通过苍蝇介导的传染（“水平”感染栖息地的其他草）传播其孢子。有性繁殖的真菌物种通常被分类在棒孢菌科的Epichelium属中，而无性或分生孢子无性型通常被命名为Neotyphodium属。到目前为止，分类学上的混乱模糊了真菌和其草宿主之间有趣的共生生态学。通过对几个靶向核基因的DNA测序，在广泛的地理范围内收集的样本，以及真菌分离株之间交配成功的实验室和花园测试，Schardl博士继续分析Epichelium和Neotyphodium物种和疑似亲属的系统发育关系。反过来，这些真菌的谱系相关的群体或分支与它们的宿主草植物相关，以确定这种共生关系是否密切跟踪了草的物种形成（“共同物种形成”）的历史，或者新的草宿主是否被感染，如果是这样，主要是通过真菌的有性或无性形式。 DNA测序的新分子方法允许对单独命名的有性和无性形式的真菌之间的谱系或系统发育关系进行精细的分析，Schardl博士正在以富有想象力的方式将其应用于草坪草和相关草物种的真菌共生体的生态学迷人系统。真菌是否“跟踪”其草宿主的物种形成历史，无性变体是否起源于有性真菌形式或相反，以及真菌物种是否杂交以产生一些目前记录的Neotyphodium anamorphs，只是这个新奖项所追求的一些问题。