Costs of fungal endophyte infection in Lolium perenne genotypes from Eurasia and North Africa under extreme resource limitation
Costs of fungal endophyte infection in Lolium perenne genotypes from Eurasia and North Africa under extreme resource limitation
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DOI：
10.1016/j.envexpbot.2006.10.001
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发表时间：
2007-06-01
影响因子：
5.7
通讯作者：
Cheplick, Gregory P.
中科院分区：
文献类型：
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作者：
Cheplick, Gregory P.
众所周知，无性、叶栖内生真菌对多年生黑麦草生长的影响是不一致的，而且似乎取决于环境条件和寄主遗传。在一些饲用作物品种中，内生菌的正向和负向生长效应都已被记录下来。由于内生菌利用寄主光合作用产物，因此假设在极端资源限制下，内生菌会将生长成本转嫁给受感染的植物。对来自意大利、土耳其、摩洛哥和突尼斯的材料进行了调查，研究了内生真菌Neotyphdium lolii侵染其寄主多年生牧草的潜在代价。将4~5个感染多年生落叶松的(+E)基因型克隆到分株中，内生菌从一半的分株(-E)中被消灭。每个基因型的6个+E和6-E分株在营养不良的基质(蛭石)中培养5个月，培养在温度和光照控制的生长室中。采食量和采食量受采食量的影响。内生真菌侵染显著降低了根冠比和成活、光合作用的地上部比例。大多数品种的相对互作强度指数均为负值，表明寄主-内生真菌的相互作用大多是寄生的。然而，有明显的感染由基因互作；因此，内生菌介导的影响取决于特定的寄主基因型-内生菌组合。这项研究是为数不多的记录了草-内生菌共生中内生菌感染成本的研究之一。这一成本表现为根冠比和光合枝比例的降低，这对在基质养分有效性极差的条件下生长的多年生黑麦草来说是明显的。(C)2006爱思唯尔B.V.保留所有权利。
The effects of asexual, leaf-inhabiting endophytes on the growth of Lolium perenne are notoriously inconsistent and appear to be contingent on environmental conditions and host genetics. Both positive and negative growth effects of endophytes have been documented in some forage crop cultivars. Because they utilize host photosynthates, it is hypothesized that endophytes would impart a growth cost to infected plants under extreme resource limitation. The potential costs of infection by the fungal endophyte Neotyphodium lolii to its host grass, L. perenne, were investigated in accessions from Italy, Turkey, Morocco and Tunisia, the native part of the host's range. Four to five infected (+E) genotypes of L. perenne per accession were cloned into ramets, and the endophyte exterminated from half of the ramets (-E). Six +E and six -E ramets per genotype were grown for 5 months in a nutrient-poor substrate (vermiculite) within temperature- and light-controlled growth chambers. Accession and genotype within accession affected dry mass. Endophyte infection significantly reduced root:shoot ratio and the proportion of the shoot that was alive and photosynthetic. Relative interaction intensity indexes were negative for most genotypes, indicating host-endophyte associations were mostly parasitic. However, there were significant infection by genotype interactions; thus, endophyte-mediated effects depend on particular host genotype-endophyte combinations. This research is one of the few that have documented costs to endophyte infection in a grass-endophyte symbiosis. This cost, manifested as reduced root:shoot ratio and photosynthetic shoot fraction, was evident for infected L. perenne growing under conditions of extremely poor substrate nutrient availability. (c) 2006 Elsevier B.V. All rights reserved.