APS Homepage

POSTERS: Pathogen-vector/insect interactions

Why vectors like mixed infected plants? The more, the better?
Kaixi Zhao - Pennsylvania State University. Cristina Rosa- The Pennsylvania State University

Plants can be naturally infected with more than one plant virus. Here we report how mixed-infection affects vector’s behavior and plant defenses in a pathosystem with two related orthotospoviruses, Tomato spotted wilt orthotospovirus (TSWV) and Impatiens necrotic spot orthotospovirus (INSV). TSWV and INSV can be vectored by the same thrips species and in plants have an antagonistic interaction. First and second instar thrips play an essential role during virus acquisition, therefore where eggs hatch could impact Orthotospoviruses’ transmission. Our results show that female thrips prefer mixed-infected plants to lay eggs, even if they show symptoms similar to singly infected ones. Surprisingly, mixed-infection did not change the profile of plant volatiles that could be used as chemical cue to attract vector thrips. We chose then to characterize the small RNA profile of plants infected with single or double TSWV/ INSV infection, since they play a key role in determining the efficacy of RNA interference, the main antiviral defense in plants. Our data show an under-representation of viral small RNAs(vsRNAs) mapping to the intergenic region of the S and M segments in both viruses, and an increase in the total amount of 21nt and 22nt vsRNA in mixed-infected plants by different Dicers. Our study enhances the understanding of the response of plants and vectors to dual virus infection and can explain the outcome of antagonistic virus interactions.