Abstract
Plants possess a sophisticated hormone-signaling system, which includes salicylic acid (SA) and jasmonic acid (JA), to defend themselves from herbivores. In addition, this immune system is modulated by nonpathogenic microbes that live asymptomatically within intercellular spaces of host grasses. We investigated the resistance triggered by defense hormones, and that provided by endophyte Epichloë gansuensis against aphid Rhopalosiphum padi, and how the endophyte regulates this tripartite interaction. We detected that endophyte-induced plant tolerance to the aphid feeding and exogenous SA increased plant shoot biomass, root biomass, plant length, and chlorophyll content. Endophyte colonization induces the WRKY54 factor that overrides negative effects on plant growth and possibly suppresses SA accumulation. In addition, the endophyte promotes a level of JA that is antagonistic to the SA pathway. By disabling the SA mechanism for herbivore-mediated plant growth inhibition, the endophyte induces plant tolerance to herbivory.
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Acknowledgements
This research was supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDA26020202), the National Basic Research Program of China (2014CB138702); the Second Tibetan Plateau Scientific Expedition and Research (STEP) (2019QZKK0302); Program for Changjiang Scholars and Innovative Research Team in University, China (IRT17R50); Fundamental Research Funds for the Central Universities (LZUJBKY-2020-kb10) and 111 Project (B12002). Support was also provided by USDA-NIFA Multistate Project W4147 and the New Jersey Agricultural Experiment Station.
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YLH and TXC outlined the experimental setup. YLH wrote the initial draft of the manuscript. HJZ and YLH analyzed the data. JFW and CJL revised the manuscript to the present form. The manuscript was read by all authors and approved for submission.
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He, Y., Chen, T., Zhang, H. et al. Fungal Endophytes Help Grasses to Tolerate Sap-Sucking Herbivores Through a Hormone-Signaling System. J Plant Growth Regul 41, 2122–2137 (2022). https://doi.org/10.1007/s00344-021-10430-2
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DOI: https://doi.org/10.1007/s00344-021-10430-2