Endophytic fungi enhance crop resistance and natural enemy-mediated pest control through bottom-up, and top-down, synergistic ecological mechanisms

Author of the article:WANG Run-Yao1, 2** SONG Ying-Ying2 LI Li-Li2 YIN Shu-Yan1*** MEN Xing-Yuan2***

Author's Workplace：1. Shandong Agricultural University, Tai’an 271018, China; 2. Shandong Key Laboratory for Green Prevention and Control of Agricultural Pests, Institute of Plant Protection, Shandong Academy of Agricultural Sciences, Jinan 250100, China

Key Words：endophytic fungi; crop resistance; natural enemy-mediated pest control; bottom-up and top-down regulation; ecological pest management

Abstract：Endophytic fungi are widely distributed within plant tissues and play a significant role in the control of agricultural pests by regulating plant growth and development, the plant defense metabolism and via multitrophic interactions. Endophytic fungi not only promote the accumulation of defensive secondary metabolites, such as benzoxazines, alkaloids and flavonoids, but by activating defense signaling pathways, like the jasmonic acid (JA) and salicylic acid (SA) pathways, enhance plants’ resistance to sucking and chewing pests (bottom-up regulation). They can also reshape the release profile of herbivore-induced plant volatiles (HIPVs), thereby enhancing the targeted search and pest control capabilities of parasitic wasps, predatory insects and arachnids (top-down regulation). By doing this they create a synergy between “upward insect resistance and downward pest control.” This paper systematically reviews progress in research on how endophytic fungi enhance the resistance of plants to insects and promotes the biological control of pests by their natural enemies, focusing on ecological mechanisms in hormonal signaling regulation, secondary metabolite reprogramming, volatile-mediated signal transduction and multitrophic interactions. From this basis, it integrates the theory of functional plant ecological engineering to construct a multidimensional ecological regulation framework comprising “endophytic fungi, crops, pests, natural enemies and functional plants.” Finally, prospects for future research on key scientific issues, such as the stability of endophytic fungal colonization, the synergistic effects of multiple strains, field application effectiveness and ecological safety, are discussed, with the aim of providing theoretical support and a practical reference for future innovation in ecological pest control technology and sustainable agricultural development.