Xing Zhenlong, Wu Libo, Biere Arjen, Yu Hongwei, Ding Jianqing
State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China.
Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
Plant Cell Environ. 2025 Jun 19. doi: 10.1111/pce.70024.
Foliar insect herbivory could affect arbuscular mycorrhizal fungi (AMF), yet the underlying mechanisms remain understudied. Here, we examined the response of AMF symbiosis signals to foliar herbivory, using six herbaceous plant species and a generalist herbivorous insect. We found AMF colonisation was suppressed by foliar herbivory. After insect attack, plants allocated more biomass to belowground parts and the attack induced defence responses in aboveground parts. Notably, foliar herbivory increased shoot flavonoid concentrations but decreased root flavonoid concentrations. Moreover, quercetin and strigol concentrations in the root exudates were reduced by foliar herbivory. We further tested effect of the root exudates on the in-vitro germination of spores of two common AMF species. Spore germination was lower in treatments with herbivore-induced root exudates than in treatments with no-herbivore root exudates. Moreover, addition of herbivory-modified root exudates reduced AMF colonisation of healthy plants when compared to addition of root exudates from non-herbivory plants. Our results suggest that foliar herbivory weakened symbiosis signalling in root exudates, which could have contributed to the observed lower AMF colonisation following herbivory. Therefore, herbivore-induced symbiosis signalling needs to be considered when studying plant-mediated interactions between foliar herbivores and root microbes.
叶片昆虫取食可能会影响丛枝菌根真菌（AMF），但其潜在机制仍未得到充分研究。在这里，我们使用六种草本植物物种和一种多食性食草昆虫，研究了AMF共生信号对叶片取食的响应。我们发现叶片取食会抑制AMF的定殖。昆虫攻击后，植物将更多生物量分配到地下部分，并且攻击会诱导地上部分产生防御反应。值得注意的是，叶片取食会增加地上部分黄酮类化合物的浓度，但会降低地下部分黄酮类化合物的浓度。此外，叶片取食会降低根系分泌物中槲皮素和独脚金内酯的浓度。我们进一步测试了根系分泌物对两种常见AMF物种孢子体外萌发的影响。与无食草动物根系分泌物处理相比，食草动物诱导的根系分泌物处理下的孢子萌发率较低。此外，与添加非食草植物的根系分泌物相比，添加经食草作用修饰的根系分泌物会降低健康植物的AMF定殖率。我们的结果表明，叶片取食会削弱根系分泌物中的共生信号，这可能是导致取食后观察到的AMF定殖率较低的原因。因此，在研究叶片食草动物与根系微生物之间的植物介导相互作用时，需要考虑食草动物诱导的共生信号。
