The effects of Beauveria bassiana infection on the gene expression profiles of Diaphorina citri adults

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama, is a citrus pest worldwide. This pest transmits the pathogens of Huanglongbing, Candidatus Liberibacter asiaticus (CLas), and has led to huge economic losses. The use of chemical pesticides is the first choice for field pest control, while resistance, resurgence, and residue (3R) problems have received widespread attention. Biological control is an optional and effective method for D. citri management and needs to be developed. In this study, eleven entomopathogenic fungi strains were collected, and their morphologies were recorded. After blasting with the ITS sequences, eight strains were identified as Beauveria bassiana, and three strains were Metarhizium anisopliae. The pathogenicity of these fungi on D. citri adults at 1.0 × 107 conidia/mL was tested, with the LT50 ranging from 4.764 to 8.551. The virulence of B. bassiana strain XM-D1 was further evaluated, and the LC50 was 4.93 × 105 conidia/mL. A total of 155 and 894 differentially expressed genes (DEGs) were identified in the samples after 24 and 48 h of XM-D1 infection, respectively. Further analyses found that the pathways of apoptosis, cholesterol metabolism, fatty acid biosynthesis, and vitamin digestion and absorption could be involved in the response of D. citri adults to 48 h of infection, and DEGs encoding chaperone proteins, cuticle protein 12.5, P450s, and lysozymes may play important roles in immune defense. Our preliminary findings enrich the entomopathogenic fungi repository and shed light on the defense mechanism of D. citri in response to B. bassiana infection at the molecular level.