ATP-binding cassette transporters ABCF2 and ABCG9 regulate rice black-streaked dwarf virus infection in its insect vector, Laodelphax striatellus (Fallen)

The majority of plant viral disease is transmitted and spread by insect vectors in the field. The small brown planthopper, Laodelphax striatellus (Fallen), is the only efficient vector for rice black-streaked dwarf virus (RBSDV), a devastating plant virus that infects multiple grain crops, including rice, maize, and wheat. Adenosine triphosphate (ATP)-binding cassette (ABC) transporters participate in various biological processes. However, little is known about whether ABC transporters affect virus infection in insects. In this study, RBSDV accumulation was significantly reduced in L. striatellus after treatment with verapamil, an effective inhibitor of ABC transporters. Thirty-four ABC transporter genes were identified in L. striatellus and expression analysis showed that LsABCF2 and LsABCG9 were significantly upregulated and downregulated, respectively, after RBSDV infection. LsABCF2 and LsABCG9 were expressed during all developmental stages, and LsABCG9 was highly expressed in the midgut of L. striatellus. Knockdown of LsABCF2 promoted RBSDV accumulation, while knockdown of LsABCG9 suppressed RBSDV accumulation in L. striatellus. Our data showed that L. striatellus might upregulate the expression of LsABCF2 and downregulate LsABCG9 expression to suppress RBSDV infection. These results will contribute to understanding the effects of ABC transporters on virus transmission and provide theoretical basis for virus management in the field.