Mechanisms of ecological adaptation in economically important fruit tree psyllids: Progress and prospects
Author of the article:NIAN Xiao-Ge1** LI Jian-Ying1** ZHANG Zhi-Xian2 RUAN Xue-Yi2 SONG Xiao-Bing1 HUANG Feng1 CHEN
Author's Workplace：1. Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; 2. College of Plant Protection, China Agricultural University, Beijing 100193, China
Key Words：Diaphorina citri; CLas; Cacopsylla chinensis; Erwinia amylovora; ecological adaptation; coevolution
Abstract：Fruit tree psyllids are globally important pests that include the Asian citrus psyllid Diaphorina citri, the Chinese pear psyllid Cacopsylla chinensis and the wolfberry psyllid Paratrioza sinica. In addition to direct feeding damage, they transmit devastating diseases such as citrus huanglongbing and pear fire blight. Furthermore, their ecological adaptability increases the frequency of population outbreaks and the likelihood of global expansion. This paper systematically reviews recent advances in research on the ecological adaptation mechanisms of economically important fruit tree psyllids from both biotic and abiotic perspectives. In terms of biotic adaptation, the huanglongbing pathogen (Candidatus Liberibacter asiaticus) hijacks the neuroendocrine signaling of D. citri to enhance female fecundity and create a microenvironment favorable for its own proliferation, while simultaneously manipulating immunity and feeding behavior, driving pathogen-vector coevolution on multiple levels. Similarly, the fire blight pathogen (Erwinia amylovora) hijacks juvenile hormone signaling in C. chinensis to increase female fecundity, suggesting that this mechanism is conserved in psyllid–pathogen interactions. Regarding abiotic adaptation, the temperature receptor genes CcTRPM and CcTRPV act as molecular switches that sense ambient temperature fluctuations and activate downstream signaling cascades to precisely regulate summer-winter polymorphism in C. chinensis. This indicates a molecular genetic mechanism of temperature-mediated phenotypic plasticity. In other psyllids, the wolfberry gall mite Aceria pallida attaches to overwintering P. sinica adults and enhances psyllid fecundity to improve its own overwintering survival, an example of the diversity of ecological adaptation strategies in this group. Ecological adaptation strategies vary considerably among other psyllids. The high-temperature sensitivity of C. citrisuga restricts its distribution to high-altitude areas of southwestern China, resulting in a distinct ecological niche partition from low-altitude citrus-producing regions where D. citri predominates. Future research should prioritize the systematic separation of the multipartite interaction network among pathogens, temperature, and psyllids. A key objective is to elucidate how environmental signals drive phenotypic plasticity in psyllids via epigenomic reprogramming, which in turn modulates pathogen transmission dynamics and triggers pest population outbreaks. With respect to control strategy, temperature receptors and key genes involved in neuroendocrine signaling pathways represent promising molecular targets for the development of next-generation green control technologies that both disrupt ecological adaptation, and interfere with pathogen–vector crosstalk.