Feldman Tracy S, O'Brien Heath E, Arnold A Elizabeth
Biology Department, Duke University, Box 90338, Durham, NC 27708-0338, USA.
Microb Ecol. 2008 Nov;56(4):742-50. doi: 10.1007/s00248-008-9393-8. Epub 2008 May 20.
Claviceps paspali, a common fungal pathogen of Paspalum grasses, attracts moth vectors by producing sugary exudates in the grass florets it infects. These exudates also support mycoparasitic Fusarium species that may negatively influence C. paspali fitness. We examined the potential for moths on which C. paspali depends to also transmit mycoparasitic Fusarium and fungal endophytes, which inhabit asymptomatic plant tissue and may influence host susceptibility to pathogens. We quantified infections by C. paspali, Fusarium spp., and endophytic fungi associated with Paspalum spp. at focal sites in the southeastern USA and used data from the nuclear internal transcribed spacer (ITS rDNA) to compare communities of plant-associated and moth-borne fungi. ITS sequences of moth-borne fungi were identical to reference sequences of mycoparasitic Fusarium heterosporum and to three distinct endophytic fungi isolated from Paspalum species. Our results demonstrate an unexpected overlap of fungal communities between disparate locations and among plant species and plant tissues, and suggest an unexpected role of moths, which vector a plant pathogen, to transmit other guilds of fungi. In turn, the potential for insects to transmit plant pathogens as well as mycoparasites and endophytic fungi suggests complex interactions underlying a commonly observed grass-pathogen system.
雀稗麦角菌是雀稗属禾本科植物的一种常见真菌病原体,它通过在其所感染的禾本科小花中产生含糖分泌物来吸引蛾类传粉者。这些分泌物也为可能对雀稗麦角菌适应性产生负面影响的真菌寄生镰刀菌属物种提供了支持。我们研究了雀稗麦角菌所依赖的蛾类是否也会传播真菌寄生镰刀菌和真菌内生菌的可能性,这些内生菌栖息在无症状的植物组织中,可能会影响宿主对病原体的易感性。我们对美国东南部重点区域的雀稗属植物中与雀稗麦角菌、镰刀菌属以及内生真菌相关的感染情况进行了量化,并利用核糖体DNA内转录间隔区(ITS rDNA)的数据来比较与植物相关的真菌群落和蛾类携带的真菌群落。蛾类携带真菌的ITS序列与真菌寄生异孢镰刀菌的参考序列以及从雀稗属植物中分离出的三种不同内生真菌的参考序列相同。我们的研究结果表明,不同地点之间以及不同植物物种和植物组织之间的真菌群落存在意外的重叠,并表明作为植物病原体传播媒介的蛾类在传播其他真菌类群方面具有意外的作用。反过来,昆虫传播植物病原体以及真菌寄生物和内生真菌的可能性表明,在一个常见的禾本科植物 - 病原体系统背后存在着复杂的相互作用。