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Site‐ and species‐specific differences in endophyte occurrence in two herbaceous plants
Author(s) -
GANGE ALAN C.,
DEY SOMA,
CURRIE AMANDA F.,
SUTTON BRIAN C.
Publication year - 2007
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1111/j.1365-2745.2007.01245.x
Subject(s) - biology , herbaceous plant , endophyte , cirsium arvense , botany , herbivore , plant use of endophytic fungi in defense , epichloë , host (biology) , poaceae , symbiosis , thistle , ecology , bacteria , genetics
Summary1 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.