24K Protein from Citrus psorosis virus (CPsV) interferes with plant miRNA biogenesis

REYES, C.A.

Conferencia; XXII Conference of the International Organization of Citrus Virologists (IOCV); 2022

IOCV

RNA Silencing is a primary immune defense against viruses in plants. However, plant viruses have developed viral suppressors of RNA silencing (VSRs) to counterattack plant defense and facilitate virus infection. Citrus psorosis virus (CPsV) is a three-partite, non-enveloped, negative-sense, ssRNA virus that encodes 4 proteins; one of them is a small 24kDa protein (24K). In previous works we showed that CPsV down-regulates the accumulation of a set of endogenous miRNAs in Citrus sinensis plants with a concomitant up-regulation in the accumulation of their target transcripts. Besides, we demonstrated that 24KCPsV protein interacts with miRNAs precursors (pre-miRNA) in vivo causing a higher accumulation of unprocessed species. Here, we showed that CPsV-infected citrus plants exhibit a higher accumulation of unprocessed pre-miRNAs compared to healthy plants by RT-qPCR. Besides, we found subcellular co-localization of 24KCPsV with different components of the miRNAs biogenesis machinery (DICER-LIKE 1: DCL1; HYPONASTIC LEAVES 1: HYL1 and SERRATE: SE) in D-bodies, forming typical aggregates. In vivo interaction between 24KCPsV and HYL1 or SE was also verified by BiFC and CoIP. These results confirm the interference of 24KCPsV with miRNAs biogenesis pathway either explained by protein-protein or protein-RNA interaction.