Foliar endophytic fungi are present in almost all vascular plants. The composition of endophyte communities varies among plant individuals. Likely, but understudied, sources of this variation are the species composition of the plant community and initial attacks by insect herbivores. We addressed these issues by characterizing fungal endophyte communities on leaves of chestnut (Castanea sativa) grown in pure vs. mixed stands. We used ITS metabarcoding methods to identify endophytic fungi associated with galls caused by the invasive gall wasp, Dryocosmus kuriphilus, and with surrounding chestnut leaf tissues. We found 1378 different OTUs. The richness, diversity and composition of endophyte communities differed between galls and surrounding leaf tissues but were independent of forest stand composition. Fungal endophyte richness was lower in galls than in surrounding leaf tissues. Most differences in the composition of fungal endophyte communities between galls and foliar tissues were due to OTU turnover. These results suggest that insect-induced galls provide a particular habitat condition for endophytic microorganisms, regardless of forest species composition. A better understanding of endophyte biology is important to improve their use as biocontrol agents of galling insects.

叶脉内生真菌几乎存在于所有维管植物中。内生菌群落的组成在植物个体之间变化。这种变化的可能（但尚未研究）是植物群落的物种组成和昆虫食草动物的初始攻击。我们通过在纯林与混交林中生长的板栗（栗）（Castanea sativa）叶片上表征真菌内生菌群落来解决这些问题。我们使用ITS metabarcoding方法来识别与侵入性胆黄蜂Dryocosmus kuriphilus引起的胆汁相关的内生真菌，并带有周围的栗叶组织。我们找到了1378个不同的OTU。胆囊和周围叶片组织之间的内生菌群落的丰富性，多样性和组成各不相同，但与林分组成无关。胆囊中真菌内生菌的丰富度低于周围叶片组织。胆囊和叶组织之间真菌内生菌群落组成的大部分差异是由于OTU转换造成的。这些结果表明，无论森林物种组成如何，昆虫引起的胆汁都为内生微生物提供了特殊的栖息地条件。对内生菌生物学的更好理解对于提高其作为gall虫的生物防治剂的用途很重要。