An effector from cotton bollworm oral secretion impairs host plant defense signaling.
Chun-Yu ChenYao-Qian LiuWei-Meng SongDian-Yang ChenFang-Yan ChenXue-Ying ChenZhi-Wen ChenSheng-Xiang GeChen-Zhu WangShuai ZhanXiao-Ya ChenYing-Bo MaoPublished in: Proceedings of the National Academy of Sciences of the United States of America (2019)
Insects have evolved effectors to conquer plant defense. Most known insect effectors are isolated from sucking insects, and examples from chewing insects are limited. Moreover, the targets of insect effectors in host plants remain unknown. Here, we address a chewing insect effector and its working mechanism. Cotton bollworm (Helicoverpa armigera) is a lepidopteran insect widely existing in nature and severely affecting crop productivity. We isolated an effector named HARP1 from H. armigera oral secretion (OS). HARP1 was released from larvae to plant leaves during feeding and entered into the plant cells through wounding sites. Expression of HARP1 in Arabidopsis mitigated the global expression of wounding and jasmonate (JA) responsive genes and rendered the plants more susceptible to insect feeding. HARP1 directly interacted with JASMONATE-ZIM-domain (JAZ) repressors to prevent the COI1-mediated JAZ degradation, thus blocking JA signaling transduction. HARP1-like proteins have conserved function as effectors in noctuidae, and these types of effectors might contribute to insect adaptation to host plants during coevolution.