Site- and species-specific differences in endophyte occurrence in two herbaceous plants
Site- and species-specific differences in endophyte occurrence in two herbaceous plants
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DOI：
10.1111/j.1365-2745.2007.01245.x
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发表时间：
2007-07-01
影响因子：
5.5
通讯作者：
Sutton, Brian C.
中科院分区：
文献类型：
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作者：
Gange, Alan C.;Dey, Soma;Sutton, Brian C.
1. 内生真菌存在于所有植物的活组织中，但与草和树相比，对草本物种的生态学知之甚少。这些真菌在培养过程中产生一系列代谢物，有证据表明它们可以增强植物对食草昆虫的抵抗力。由于草本植物内生菌被认为是一种非特化的、普遍存在的分类群，我们假设它们在两个密切相关的植物物种中的存在不会因当地植物群落而变化。此外，我们期望发现内生菌的发生与草食性昆虫的发生呈负相关。我们通过从五个种群中分离出内生菌来验证这些假设，这些种群分别生长在相距约13公里的普通白菊（Leucanthemum vulgare）和鸢尾草（Cirsium arvense）。同时还测定了采叶蝇对各植物的危害。单株含真菌种类较多，单叶分离菌数量也较多。几种真菌在两种植物中表现出差异，但这些差异在不同地点并不一致。内生菌组合的相似性随着林间距离的增加而降低，但在乡土草中没有。我们得出结论，内生菌要么更容易定殖，要么在宿主体内具有更大的活性（或两者兼而有之）。叶螨攻击与普通L.的内生菌总种数呈正相关，而与arvense .的内生菌总种数不相关，而毛藻种数的发生与昆虫攻击呈负相关。不同内生菌种类间的显著相关关系仅为5%，而不同内生菌种类间的显著相关关系为43%。本研究对了解植物抗虫性的影响因素具有重要意义。这是关于内生真菌影响草本植物昆虫寄主选择的首次报道。植物中丰富的非特化内生菌意味着它们是植物-食草动物关系中一个被忽视但重要的方面。
1. Endophyte fungi exist within the living tissues of all plants, but compared with grasses and trees, remarkably little is known about their ecology in herbaceous species. These fungi produce an array of metabolites in culture and there is some evidence that they can increase the resistance of plants to herbivorous insects.2. As herbaceous plant endophytes are thought to be unspecialized, ubiquitous taxa, we hypothesized that their occurrence within two closely related plant species would not vary between local plant communities. Furthermore, we expected to find negative relations between endophyte occurrence and that of a herbivorous insect.3. We tested these hypotheses by isolating endophytes from Leucanthemum vulgare and Cirsium arvense (Asteraceae) plants growing together in five populations, each about 13 km apart. Damage by the leaf mining fly, Chromatomyia syngenesiae, was also measured on each plant.4. C. arvense harboured more species of fungi per plant and the number of isolates recovered per leaf was also higher. Several fungi showed differences in occurrence within the two plants, but these differences were not consistent between sites. The similarity in the endophyte assemblage decreased with increasing intersite distance in C. arvense, but not in L. vulgare. We conclude that endophytes either colonize C. arvense more readily or have greater activity within this host (or both).5. Leaf miner attack was positively related to total endophyte species number in L. vulgare, but not so in C. arvense, while occurrence of Chaetomium species was negatively associated with insect attack in both plants. In L. vulgare, only 5% of relations between occurrence of different endophyte species were significant, but in C. arvense this figure was 43% and all were negative.6. This study has important implications for understanding the factors that influence plant resistance to insects. It is the first report of endophytic fungi affecting host plant choice by insects in herbaceous plants. The abundance of unspecialized endophytes in forbs means that they are a neglected, but important, aspect of plant-herbivore relations.