Xiaobei Liu, Yumeng Zhang, Frédéric Francis, Yumeng Cheng, Yanxia Liu, Julian Chen, Yong Zhang.Induced Bowman-Birk trypsin inhibitor TaBBTI-1 in wheat during poor-host interactions with aphids confers broad-spectrum resistance to insect herbivores.
International Journal of Biological Macromolecules，2026
https://doi.org/10.1016/j.ijbiomac.2026.150204
Abstract
Aphids are phloem-feeding insects that cause significant yield losses on major crops such as wheat. While non-host resistance is considered the most durable and efficient immune system of plants, its mechanisms against aphids remain poorly understood. Here, aphid bioassays and electrical penetration graphs allowed to classify Sitobion avenae as a host, Myzus persicae as a poor-host, and Acyrthosiphon pisum as a non-host on wheat. Pre-infestation by M. persicae induced stronger wheat resistance during poor-host interactions, significantly reducing subsequent aphid nymph production compared to S. avenae pre-infestation. Comparative transcriptomic analysis of wheat under host versus poor-host interactions uncovered that the upregulated genes induced by M. persicae infestation primarily associated with alpha-linolenic acid metabolism and jasmonic acid (JA) biosynthesis pathways. Phytohormone quantification showed that M. persicae feeding, but not S. avenae, elevated endogenous levels of JA in wheat. Notably, a Bowman-Birk trypsin inhibitor of wheat, designated as TaBBTI-1, was specifically and strongly induced by M. persicae, and exogenous JA application to wheat plants dramatically upregulated TaBBTI-1. Feeding on artificial diets supplemented with recombinant TaBBTI-1 protein and wheat leaves overexpressing TaBBTI-1 significantly impaired the fecundity of S. avenae. Furthermore, ectopic expression of TaBBTI-1 in Nicotiana tabacum dramatically reduced host susceptibility to M. persicae and lepidopteran pest Helicoverpa armigera, demonstrating broad-spectrum resistance against herbivorous insects. This study provides novel insights into the molecular mechanisms underlying non−/poor-host resistance of wheat against aphids and development of novel and durable pest control in crop plants.